# Perpetuum Mobile

Guest Post by Willis Eschenbach

Since at least the days of Da Vinci, people have been fascinated by perpetual motion machines. One such “perpetuum mobile” designed around the time of the civil war is shown below. It wasn’t until the development of the science of thermodynamics that it could be proven that all such mechanisms are impossible. For such machines to work, they’d have to create energy, and energy cannot be either created or destroyed, only transformed.

I bring this up for a curious reason. I was reading the Jelbring hypothesis this afternoon, which claims that greenhouse gases (GHGs) are not the cause of the warming of the earth above the theoretical temperature it would have without an atmosphere. Jelbring’s hypothesis is one of several “gravito-thermal” theories which say the heating of the planet comes from gravity rather than (or in some theories in addition to) the greenhouse effect. His thought experiment is a planet with an atmosphere. The planet is isolated from the universe by an impervious thermally insulating shell that completely surrounds it, and which prevents any energy exchange with the universe outside. Inside the shell, Jelbring says that gravity makes the upper atmosphere colder and the lower atmosphere warmer. Back around 2004, I had a long discussion on the “climateskeptics” mailing list with Hans Jelbring. I said then that his theory was nothing but a perpetual motion machine, but at the time I didn’t understand why his theory was wrong. Now I do.

Dr. Robert Brown has an fascinating post on WUWT called “Earth’s baseline black-body model – a damn hard problem“. On that thread, I had said that I thought that if there was air in a tall container in a gravity field, the temperature of the air would be highest at the bottom, and lowest at the top. I said that I thought it would follow the “dry adiabatic lapse rate”, the rate at which the temperature of dry air drops with altitude in the earth’s atmosphere.

Dr. Brown said no. He said that at equilibrium, a tall container of air in a gravity field would be the same temperature everywhere—in other words, isothermal.

I couldn’t understand why. I asked Dr. Brown the following question:

Thanks, Robert, With great trepidation, I must disagree with you.

Consider a gas in a kilometre-tall sealed container. You say it will have no lapse rate, so suppose (per your assumption) that it starts out at an even temperature top to bottom.

Now, consider a collision between two of the gas molecules that knocks one molecule straight upwards, and the other straight downwards. The molecule going downwards will accelerate due to gravity, while the one going upwards will slow due to gravity. So the upper one will have less kinetic energy, and the lower one will have more kinetic energy.

After a million such collisions, are you really claiming that the average kinetic energy of the molecules at the top and the bottom of the tall container are going to be the same?

I say no. I say after a million collisions the molecules will sort themselves so that the TOTAL energy at the top and bottom of the container will be the same. In other words, it is the action of gravity on the molecules themselves that creates the lapse rate.

Dr. Brown gave an answer that I couldn’t wrap my head around, and he recommended that I study the excellent paper of Caballero for further insight. Caballero discusses the question in Section 2.17. Thanks to Dr. Browns answer plus Caballero, I finally got the answer to my question. I wrote to Dr. Brown on his thread as follows:

Dr. Brown, thank you so much. After following your suggestion and after much beating of my head against Caballero, I finally got it.

At equilibrium, as you stated, the temperature is indeed uniform. I was totally wrong to state it followed the dry adiabatic lapse rate.

Now, consider a collision between two of the gas molecules that knocks one molecule straight upwards, and the other straight downwards. The molecule going downwards will accelerate due to gravity, while the one going upwards will slow due to gravity. So the upper one will have less kinetic energy, and the lower one will have more kinetic energy.

After a million such collisions, are you really claiming that the average kinetic energy of the molecules at the top and the bottom of the tall container are going to be the same?

What I failed to consider is that there are fewer molecules at altitude because the pressure is lower. When the temperature is uniform from top to bottom, the individual molecules at the top have more total energy (KE + PE) than those at the bottom. I said that led to an uneven distribution in the total energy.

But by exactly the same measure, there are fewer molecules at the top than at the bottom. As a result, the isothermal situation does in fact have the energy evenly distributed. More total energy per molecules times fewer molecules at the top exactly equals less energy per molecule times more molecules at the bottom. Very neat.

Finally, before I posted my reply, Dr. Brown had answered a second time and I hadn’t seen it. His answer follows a very different (and interesting) logical argument to arrive at the same answer. He said in part:

Imagine a plane surface in the gas. In a thin slice of the gas right above the surface, the molecules have some temperature. Right below it, they have some other temperature. Let’s imagine the gas to be monoatomic (no loss of generality) and ideal (ditto). In each layer, the gravitational potential energy is constant. Bear in mind that only changes in potential energy are associated with changes in kinetic energy (work energy theorem), and that temperature only describes the average internal kinetic energy in the gas.

Here’s the tricky part. In equilibrium, the density of the upper and lower layers, while not equal, cannot vary. Right? Which means that however many molecules move from the lower slice to the upper slice, exactly the same number of molecules must move from the upper slice to the lower slice. They have to have exactly the same velocity distribution moving in either direction. If the molecules below had a higher temperature, they’d have a different MB [Maxwell-Boltzmann] distribution, with more molecules moving faster. Some of those faster moving molecules would have the right trajectory to rise to the interface (slowing, sure) and carry energy from the lower slice to the upper. The upper slice (lower temperature) has fewer molecules moving faster — the entire MB distribution is shifted to the left a bit. There are therefore fewer molecules that move the other way at the speeds that the molecules from the lower slice deliver (allowing for gravity). This increases the number of fast moving molecules in the upper slice and decreases it in the lower slice until the MB distributions are the same in the two slices and one accomplishes detailed balance across the interface. On average, just as many molecules move up, with exactly the same velocity/kinetic energy profile, as move down, with zero energy transport, zero mass transport, and zero alteration of the MB profiles above and below, only when the two slices have the same temperature. Otherwise heat will flow from the hotter (right-shifted MB distribution) to the colder (left-shifted MB distribution) slice until the temperatures are equal.

It’s an interesting argument. Here’s my elevator speech version.

• Suppose we have an isolated container of air which is warmer at the bottom and cooler at the top. Any random movement of air from above to below a horizontal slice through the container must be matched by an equal amount going the other way.

• On average, that exchange equalizes temperature, moving slightly warmer air up and slightly cooler air down.

• Eventually this gradual exchange must lead to an isothermal condition.

I encourage people to read the rest of his comment.

Now, I see where I went wrong. Following the logic of my question to Dr. Brown, I incorrectly thought the final equilibrium arrangement would be where the average energy per molecule was evenly spread out from top to bottom, with the molecules having the same average total energy everywhere. This leads to warmer temperature at the bottom and colder temperature at elevation. Instead, at thermal equilibrium, the average energy per volume is the same from top to bottom, with every cubic metre having the same total energy. To do that, the gas needs to be isothermal, with the same temperature in every part.

Yesterday, I read the Jelbring hypothesis again. As I was reading it, I wondered by what logic Jelbring had come to the conclusion that the atmosphere would not be isothermal. I noticed the following sentence in Section 2.2 C (emphasis mine):

The energy content in the model atmosphere is fixed and constant since no energy can enter or leave the closed space. Nature will redistribute the contained atmospheric energy (using both convective and radiative processes) until each molecule, in an average sense, will have the same total energy. In this situation the atmosphere has reached energetic equilibrium.

He goes on to describe the atmosphere in that situation as taking up the dry adiabatic lapse rate temperature profile, warm on the bottom, cold on top. I had to laugh. Jelbring made the exact same dang mistake I made. He thinks total energy evenly distributed per molecule is the final state of energetic equilibrium, whereas the equilibrium state is when the energy is evenly distributed per volume and not per molecule. This is the isothermal state. In Jelbrings thought experiment, contrary to what he claims, the entire atmosphere of the planet would end up at the same temperature.

In any case, there’s another way to show that the Jelbring hypothesis violates conservation of energy. Again it is a proof by contradiction, and it is the same argument that I presented to Jelbring years ago. At that time, I couldn’t say why his “gravito-thermal” hypothesis didn’t work … but I knew that it couldn’t work. Now, I can see why, for the reasons adduced above. In addition, in his thread Dr. Brown independently used the same argument in his discussion of the Jelbring hypothesis. The proof by contradiction goes like this:

Suppose Jelbring is right, and the temperature in the atmosphere inside the shell is warmer at the bottom and cooler at the top. Then the people living in the stygian darkness inside that impervious shell could use that temperature difference to drive a heat engine. Power from the heat engine could light up the dark, and provide electricity  for cities and farms. The good news for perpetual motion fans is that as fast as the operation of the heat engine would warm the upper atmosphere and cool the lower atmosphere, gravity would re-arrange the molecules once again so the prior temperature profile would be restored, warm on the bottom and cold on the top, and the machine would produce light for the good citizens of Stygia   … forever.

As this is a clear violation of conservation of energy, the proof by contradiction that the Jelbring hypothesis violates the conservation of energy is complete.

Let me close by giving my elevator speech about the Jelbring hypothesis. Hans vigorously argues that no such speech is possible, saying

There certainly are no “Elevator version” of my paper which is based on first principal physics. It means that what I have written is either true or false. There is nothing inbetween.

Another “gravito-thermal” theorist, Ned Nikolov, says the same thing:

About the ‘elevator speech’ – that was given in our first paper! However, you apparently did not get it. So, it will take far more explanation to convey the basic idea, which we will try to do in Part 2 of our reply.

I don’t have an elevator speech for the Nikolov & Zeller theory (here, rebuttal here) yet, because I can’t understand it. My elevator speech for the Jelbring hypothesis, however, goes like this:

• If left undisturbed in a gravity field, a tall container of air will stratify vertically, with the coolest air at the top and the warmest air at the bottom.

• This also is happening with the Earth’s atmosphere.

• Since the top of the atmosphere cannot be below a certain temperature, and the lower atmosphere must be a certain amount warmer than the upper, this warms the lower atmosphere and thus the planetary surface to a much higher temperature than it would be in the absence of the atmosphere.

• This is the cause of what we erroneously refer to as the “greenhouse effect”

Now, was that so hard? It may not be the best, I’m happy to have someone improve on it, but it covers all the main points. The claim that “gravito-thermal” theories are too complex for a simple “elevator speech” explanation doesn’t hold water.

But you can see why such an elevator speech is like garlic to a vampire, it is anathema to the “gravito-thermal” theorists—it makes spotting their mistakes far too easy.

w.

## 911 thoughts on “Perpetuum Mobile”

1. ShrNfr says:

However, we do have a real heat source in the earth’s core with the fission of heavy nuclei. Not perhaps a lot, but some. I never have gotten any really good estimates of how large the effect is, and I am not enough of a geologist to derive it. Anyone around have an idea??

2. gerard says:

I have a partner who has been taken in by the Thrive Movement and especially the Free energy -torus machine I have tried to explain about nergy to no avail. The Thrive promoters are linking their philosphy to climate change and saving the planet by promoting their device as a saviour.

3. I think Hans uses a definition which is ‘per unit area’
There is more room at the top of the atmosphere for more thinly spread molecules. More area per isobar as altitude increases. Needs thinking about.
I’ll sleep on it.

4. Josh C says:

ShrNfr:
Per Wikipedia “Heat flows constantly from its sources within the Earth to the surface. Total heat loss from the earth is 44.2 TW (4.42 × 1013 watts).[12] Mean heat flow is 65 mW/m2 over continental crust and 101 mW/m2 over oceanic crust.[12] This is approximately 1/10 watt/square meter on average, (about 1/10,000 of solar irradiation,)”

5. “More total energy per molecules times fewer molecules at the top exactly equals less energy per molecule times more molecules at the bottom. Very neat.”
Except that more of the total energy of the molecules at the top is locked up in gravitational potential as opposed to being available as kinetic energy capable of generating heat in collisions.

6. Bryan says:

The isothermal/adiabatic distribution for an isolated ideal gas in a gravitational field has long been debated.
For the isothermal distribution we have Maxwell, Boltzmann and Clausius.
For the adiabatic distribution we have Loschmidt, Laplace and Lagrange.
The smart money must be with the isothermal advocates but I would not regard this as a debate of which was settled and of historical interest only.
Clausius clincher argument of the perpetual motion machine being possible for the adiabatic distribution turns out to be very hard to prove with real components given 9.8K/km scale.
Perhaps Willis will suggest a real experiment with real materials to test the alternative conjectures.
Say with a thermoelectric device to make use of the temperature difference.
A computer simulation program would not be any kind of proof
I think he will find with real materials that this is beyond him
Perhaps this is why there has never been an experiment to settle the matter!
If the adiabatic conjecture turned out to be correct I’m sure there would be an explanation that did not conflict with the second law.
Here for instance is a member of the physics department of the University of California making a very up to date case for the adiabatic distribution.
http://arxiv.org/PS_cache/arxiv/pdf/0812/0812.4990v3.pdf

7. Mark T says:

Some Qs:
1. can the same result be found using gas laws, i.e., as P drops, so drops n thus leaving T unchanged? Seems reasonable.
2. do P and n necessarily change 1:1? I do not know this answer.
3. in light of 1., what if the total volume of the cylinder is not fixed?
4. in light of 2., what if they do not change 1:1?
Both 3. and 4. seem like complications beyond my reach.
Mark

8. Final thought for the night. Here’s the reply I gave Robert Brown on my site Earlier today:
Robert Brown says:
Second, my comment about egregious violation of the laws of thermodynamics were specific to Jelbring, who (IIRC, I’m not looking at his article again as I type this) explicitly asserted a column of fluid with no energy inputs, and then claimed that in equilibrium it would exhibit a thermal gradient. No, it wouldn’t.

Hi Robert,
I think the laws of thermodynamics talk about energy, rather than temperature or heat, but there are several formulations of them, so maybe we’d better discover who is using which definitions. We’d better do this, because in the application of classical mechanics to energy distribution in the model atmosphere, as defined by Hans Jelbring, there will indeed be a thermal gradient, as confirmed by Graeff’s empirical experimental data (Which should be replicated by an accredited laboratory).
“if A and B are placed in thermal contact, they will be in mutual thermal equilibrium, specifically no net heat will flow from A to B or B to A.” That’s the zeroth law.
Assuming your A and B have at least some dimension, then a thermal gradient across them would mean that the top surface of A will be at the same temperature as the bottom surface of B where they contact. Therefore no heat will flow. Even so, the average temperature of the whole of body A will be higher than that of B. QED.
http://www.emc.maricopa.edu/faculty/farabee/biobk/biobookener1.html
Laws of Thermodynamics
Energy exists in many forms, such as heat, light, chemical energy, and electrical energy. Energy is the ability to bring about change or to do work. Thermodynamics is the study of energy.
First Law of Thermodynamics: Energy can be changed from one form to another, but it cannot be created or destroyed. The total amount of energy and matter in the Universe remains constant, merely changing from one form to another. The First Law of Thermodynamics (Conservation) states that energy is always conserved, it cannot be created or destroyed. In essence, energy can be converted from one form into another. Click here for another page (developed by Dr. John Pratte, Clayton State Univ., GA) covering thermodynamics.
The Second Law of Thermodynamics states that “in all energy exchanges, if no energy enters or leaves the system, the potential energy of the state will always be less than that of the initial state.” This is also commonly referred to as entropy. A watchspring-driven watch will run until the potential energy in the spring is converted, and not again until energy is reapplied to the spring to rewind it.
———————-
I’m not seeing the words ‘heat’ or ‘temperature’ in these definitions, so please could you clarify. Thanks.
I’m not looking at his article again as I type this
Maybe you should. This is one of Jelbring’s chief complaints. People answer what they think he said, instead of answering what he actually said.

9. Peter Spear says:

I think there is still a bit of a fudge factor in that elevator speech.
“Since the top of the atmosphere cannot be below a certain temperature…”
Why? It can’t be below absolute zero but that isn’t relevant here.

10. Willis Eschenbach wrote:

Back around 2004, I had a long discussion on the “climateskeptics” mailing list with Hans Jelbring. I said then that his theory was nothing but a perpetual motion machine, but at the time I didn’t understand why his theory was wrong. Now I do.

Yes, it was a long discussion and my, how time flies when you’re having fun. It’s even more fun when you finally “get it”, whatever the “it” is that’s been bugging you.
And thanks again for your help around that time and continuing pedagogy. Yer blood’s worth bottlin’ Willis.

11. I think I need to hear an elevator speech for why “same total energy per unit volume is a physical necessity. That is not obvious at all.
Here is another elevator speech for why in the constant insolation example you get an Isothermal atmosphere.
You have a fixed amount of energy per unit (Eg) area received by the ground. This is a experiment in spherical symmetry. Things like temperature, pressure, potential energy only vary by r (radius). So at the ground, at equilibrium, you have some temperature Tg = T(r=ground) that we will constrain by the SB law of a black-body ground. The catch is that in order to radiate the ground with Eg, you must have a uniform shell at r=(very large) also radiating Eg uniformly over its entire area. When you dissipate the energy per area by 1/r^2, you also increase the area of the shell radiating the ground by r^2. But if the shell is radiating at Eg, as a black body, then the temperature of the shell is Tg, the same temperature as the ground. So T(r) = Tg at r=ground and Tg at r=(very large). But (very large) is arbitrary, so it can be any value between ground and infinity. Therefore, T(r) = Tg at all r. Isothermal regardless of pressure and gravitational potential energy.
So I can get to Isothermal with the completely artificial initial conditions of uniform insolation. If and only If. Does that tell us anything useful about the real world? I’m skeptical. We need day and night.

12. Willis Eschenbach says:

ShrNfr says:
January 19, 2012 at 4:03 pm

However, we do have a real heat source in the earth’s core with the fission of heavy nuclei. Not perhaps a lot, but some. I never have gotten any really good estimates of how large the effect is, and I am not enough of a geologist to derive it. Anyone around have an idea??

ShrNfr, thanks for a good question. I ran the numbers in the past. I don’t have them in front of me, but it is very small, less than a tenth of a watt per square metre from memory.
There are a variety of geothermal regions, and hot vents under the sea, and hot springs and pools on land. But you have to consider—for every hot springs you know of, there are thousands of square miles of land with no hot springs, where if you go to sleep in the morning, you wake up very cold.
So yes, you are right, there is a heat source down under. But it is very small, even if we have greatly underestimated it. That’s why sleeping on the bare ground is dang chilly.
All the best,
w.

13. > If left undisturbed in a gravity field, a tall container of air will stratify vertically,
> with the coolest air at the top and the warmest air at the bottom.
My thermodynamics is a bit rusty, but I am fairly sure that warm air always rises to the top.

14. Ian H says:

It is called the “adiabatic” lapse rate for a reason. It arises from adiabatic processes. What you are describing is the exact opposite of adiabatic. Your atmosphere is static and you allow it to reach a static thermal equilibrium over a very long period of time. Under those conditions you will indeed see equal temperatures everywhere. Hey – it isn’t at all surprising that you can get rid of the adiabatic lapse rate if your model eliminates all possibility of adiabatic processes.
But add in some adiabatic action – a nice little bit of vigorous vertical mixing – and the temperature gradient reappears. The elevator speech goes thus: “When air moves in a vertical airflow from the top to the bottom it is compressed and thus heats. When air moves in a vertical airflow from the bottom to the top it is decompressed and thus cools. In an atmosphere with a lot of vertical mixing you therefore will see a temperature gradient.”
Our atmosphere has such a temperature gradient.

15. richard verney says:

I am skeptical of both the gravitaional model and the GHG model.
With respect to the former, i think that there are a number of factors overlooked, the extent to which they may be material is moot.
First, gravity is not a constant force acting on the atmosphere in the sense that the atmosphere is not subject to only the force resulting from the mass of the Earth. The atmosphere is constantly being flexed by the Sun and the Moon (and even to a small extent by the Gas Giants). The diurnal bulge/atmospheric bulge is the consequence of this and is well known and this means that work is constantly being inputted into the atmosphere and as one knows a by product of work is heat. One can see the effect (an extreme example admittedly) of gravitaional pull on Io which is the most geologically active body in the solar system and this is due to the gravitational pull imposed by Jupiter and the other Galean moons. Thus there is a top down force (gravity from the Sun, Moon etc) in addition to the bottom up force of the gravity from the Earth all working on the atmosphere.
Second, and this is a factor of the first point, the atmosphere is constantly being displaced at the bottom with the ebb and flow of the tides. Again, although this is obviously weak, this too results in work being exerted on the atmosphere, the by product of which is heat,
The result of these two factors is that the atmosphere is being squeezed much like the walls of a car tyre and any motorsport fan will know that this flexing generates heat in the tyre. It is very effective at heating up the air in a tyre or at any rate maintaining the heat generated by inflating the tyre to the desired pressure.
Third, the Earth itself is a heat source and imports heat into the atmosphere. The Earth is geologically active such that the ground is well above absolute zero. Indeed, even if the sun was to stop shinning, unlike the moon, the temperature of the ground would take a long time to cool to levels seen on the dark side of the Moon. Further, we know little of the deep ocean and there is every likelihood that the amount of thermal energy being inputted into the oceans is considerably under-assessed.
Fourth, the sun warms the atmosphere irrespective of GHGs simply because of aerosol particulate matter in the atmosphere which then warms surrounding gases by conduction/thermalisation
;
May be all of this does not add up to all that much. However, the atompsphere was obviously born warm (being the left over from what was in effect a condensing fireball and the out pourings of volcanoes etc) and one only needs it to add up to the amount of energy that the system is net losing to space to maintain an equalibrium balance.
I think that there may be more to the gravitational theory than you presently give it credit. .

16. I must modify my isothermal elevator speech with a slight complication. I said that to have Eg insolation at the ground, the black body shell at r=(very large) must also be at Eg. That would only be true if the index of refraction of the ideal gas is 1.000 at all pressures (r). I don’t think it is reasonable to assume index of refraction for a compressing ideal gas does not increase with pressure. Assuming that Index of refraction (Ir(r=ground) is higher near the ground than at high altitude Ir(r=large), then there is a focusing of energy. Therefore, the energy radiated per unit area by the shell must be Es < Eg. therefore T(r=very large) < Tg. But we still have an arbibrary "very large", so I'm talking myself into a slight decrease in T(r), as r increased from "ground" to "very large". Likewise, Es(r) also must = Eg at r=ground, but decrease as r increases as the Index of refraction decreases as r increases.

17. Willis Eschenbach says:

tallbloke says:
January 19, 2012 at 4:34 pm

… The Second Law of Thermodynamics states that “in all energy exchanges, if no energy enters or leaves the system, the potential energy of the state will always be less than that of the initial state.”

Hans Jelbring, on the other hand, proposes a model earth with an impenetrable shell around it that does not allow energy to enter or leave the system, op. cit.:

A simplified model of Earth will be considered. The model planet does not rotate. It neither receives solar radiation nor emits infrared radiation into space.

In other words, no energy can get into or out of Jelbring’s system.
It seems to me that you just proved that Jelbring’s hypothesis can’t work, Tallbloke. If the potential energy of the state inside the shell can only move to where it is less than the initial state, as your quote clearly states … then how can the gravity possibly separate a low-energy, isothermal atmosphere into a higher energy state of cold at the top and warm at the bottom?
My best regards to you,
w.

18. Jeremy says:

Many people added comments, presumably physicists and engineers, indicating they had a huge problem with the Nikolov & Zeller theory. I think the issue is dead. There is no such thing as gravity creating higher temperatures.
Deep in the earth, radioactive decay (fission) of higher elements converts mass into energy. In extreme cases, larger bodies like our Sun, the gravitational pressures and heat can result in fusion, which creates even more energy by converting even more mass. The reality is that the center of our planet is well insulated from the near -273 C of space and it therefore remains hot as it is unable to dissipate the heat generated from radioactive decay quick enough to cool down. It has little to do with gravity and everything to do with fission heat and insulating properties of hundreds of miles of rock. What ultimately happens is what we call “steady state” (not the same as equilibrium).
It is the same for the atmosphere – it has energy sources from above (Sun) and from below (Earth black body & some reflected Sun) and ultimately our atmosphere has also reached a quasi-steady state which only fluctuates in response to the changes in energy gained and energy lost. Water being a huge stabilizer of our atmospheric temperature by virtue that it can store energy as it converts from water to a vapor and vice-versa. Anyone can see that after the sun’s radiative energy, water is the single biggest factor in the highly stable behavior of our atmosphere and finally orbital parameters and albedo play a small role to.
This atmospheric gravity thing is complete and utter codswallop.

19. JeffT says:

Here’s a shorter elevator speech:
If there is a temperature gradient between two parts of a system, net heat flows from the warmer part to the cooler part. If there is net heat flow within the system, it is not in equilibrium.

20. Give us time Willis.
I’ve now read and understood N&Z, and their first reply at TT to commenters from WUWT and TT. I now think their work is a paradigm-shifting cracker, but I also realize that paradigm-shifters, while ultimately incredibly simple, need to do a lot of background detail work to answer all significant details AND eliminate all possible scientific stupidities of one’s own AND cope with the psychological challenge of answering classy experts without letting one’s scientific immaturity, feyness or hippiedom lose one the necessary credibility, AND provide an FAQ-type approach to those who’ve found something to doubt and given up on the spot. Like I was sure your elevator speech last time was flawed but my answer, though still IMHO denting your thesis, didn’t really deal with it properly. And I just haven’t yet read Jellbring at all. I might find I agree with you, re Jellbring, for all I know.
Give us time, and we will repay our debts, I mean explain the new paradigm in acceptable ways and with sufficient evidence from data in the public domain. There really is a lot of stunning high quality evidence now available.

21. richard verney says:

The problem is that GHGs and back radiation does not explain the vertical temperature of the atmosphere. The inescapable conclusion of this is that the GHG model is not capable of explaining our atmosphere and that there is more at ‘play’ than the GHG model would suggest.
The vertiacal temperature profile of Earth’s atmosphere is not fully explained by the gravitational model but there does appear to be, for the main part some, causal connection. Ditto, other celestral bodies that we know of.
Presently, we do not know enough, or understand enough to fully evaluate either model. When you neither know or understand enough thought experiments invariably lead to flawed conclusions. Testing and the accumulation of observational data is required to take the matter forward/

22. David says:

Here’s my elevator speech version.
• Suppose we have an isolated container of air which is warmer at the bottom and cooler at the top. Any random movement of air from above to below a horizontal slice through the container must be matched by an equal amount going the other way.
• On average, that exchange equalizes temperature, moving slightly warmer air up and slightly cooler air down.
• Eventually this gradual exchange must lead to an isothermal condition.

The air moving up and down exchanges potential energy (PE) for kinetic energy (KE). The air moving down loses PE but gains KE, and vice versa for the air moving up. A higher KE means a higher temperature, a lower KE means a lower temperature. So the air moving down increases in temperature (KE), while the air moving up decreases in temperature (KE). This will maintain the adiabatic lapse rate, warmer air at the bottom of the column and cooler air at the top.
Your second point is wrong, there is no equalisation of temperature. Therefore, your conclusion in the third point of your elevator speech is also wrong.

23. ShrNfr says:

@Josh C Thanks.

24. Siliggy says:

To test any theory i like to look at the extremes and see if they work. So with this theory in mind, what temperature would the planet be left at if the sun were to switch off?
Should i now blame air pressure for my sunburn?

25. More briefly, one might refute the gravitational theory of atmospheric warming by reference to the empirical fact that at the top of the Earth’s atmosphere, outgoing radiant flux is closely similar to incoming radiant flux, whereas, if gravity contributed significantly to warming at the surface, Earth would be luminous, i.e., have a positive net outgoing radiant flux.
The only time gravity causes a net increase in the thermal energy content of the atmosphere is during the process of atmosphere formation, e.g., when an airless planet passes through a gas cloud. Then, gravitational compression of the gas will cause heating, the greatest effect being at the surface. However, the heat added to the atmosphere during gravitational compression will warm the surface, the added energy being then radiated to space until equilibrium is reached.

26. Josh C says:

If we wanted gravity derived concepts for heat, we should look at the temperature profiles of planets like Jupiter to see if there is a corresponding gravity induced effect. A quick look at the temperature profile here:
http://en.wikipedia.org/wiki/File:Structure_of_Jovian_atmosphere.png
If the elevator goes down far enough, there is a similar curve found in most planets with a solid cloud cover.

27. Joe Born says:

Thanks to papers brought to our attention by Paul Dennis at tallbloke’s blog, namely:
Coombes, Ch. A. and Laue, H., 1985, Am. J. Phys, v53, 272-273
Velasco, S., Roman, F.L. and White, J.A., 1995, Eur. J. Phys. v17, 43-44
I have become convinced that the isothermal hypothesis, although correct as an approximation, is theoretically true only in the limit. The former paper purports to demonstrate the strictly isothermal result, but, if my reading (with which it is not clear that Paul Dennis agrees) of the latter, Velasco et al. paper is correct, its Equation 8, a result of statistical mechanics, dictates that average kinetic energy decreases with height even at equilibrium.
A layman’s-eye view of what’s going on in a paper by Román et al., on which Velasco et al. rely, is found at tallbloke’s here: http://tallbloke.wordpress.com/2012/01/04/the-loschmidt-gravito-thermal-effect-old-controversy-new-relevance/#comment-13608

28. richard verney says on January 19, 2012 at 5:21 pm
The problem is that GHGs and back radiation …

Understand that ‘back radiation‘ is as if innumerable miniature dipole antennas tuned to specific wavelengths (as per the CO2 and H2O resonant frequencies) were present in the atmosphere and they ‘catch’ (the forward or out-to-space-bound EM energy) and re-radiate (in ALL directions including back-to-earth so-called ‘back radiation) that same EM energy AT the specific frequencies/wavelengths where they are resonant (and this includes spectral ‘line broadening’ due to molecular collisions at higher pressures e.g. at low altitudes) …
It is as simple as that.
(You do understand, too, that temperature is a measure of molecular vibration, and that gas molecules have different characteristics when ‘vibrating’ than do solids?)
.

29. Bill Illis says:

What about the gas giant planets? Jupiter at 99% hydrogen and helium has had about 4.6 billion years to become isothermic. Yet the lowest gas/liquified gas/metallic hydrogen temperatures are 35,700K and the top of the atmosphere is only 165K.

30. Well, he does have a point. IMHO gravity has never been fully explained.

31. Willis Eschenbach says:

Lucy Skywalker says:
January 19, 2012 at 5:10 pm

Give us time Willis.
I’ve now read and understood N&Z, and their first reply at TT to commenters from WUWT and TT. I now think their work is a paradigm-shifting cracker, but I also realize that paradigm-shifters, while ultimately incredibly simple, need to do a lot of background detail work to answer all significant details AND eliminate all possible scientific stupidities of one’s own AND cope with the psychological challenge of answering classy experts without letting one’s scientific immaturity, feyness or hippiedom lose one the necessary credibility, AND provide an FAQ-type approach to those who’ve found something to doubt and given up on the spot. Like I was sure your elevator speech last time was flawed but my answer, though still IMHO denting your thesis, didn’t really deal with it properly. And I just haven’t yet read Jellbring at all. I might find I agree with you, re Jellbring, for all I know.
Give us time, and we will repay our debts, I mean explain the new paradigm in acceptable ways and with sufficient evidence from data in the public domain. There really is a lot of stunning high quality evidence now available.

Lucy, thank you for your comment, but time is what you don’t have. The clock is running, the elevator speech for N&Z is way overdue. No one has done it to date, they either say nothing or like you and Ned Nikolov himself they give us Wimpy’s line from Popeye, “I’ll gladly pay you Tuesday for a hamburger today”.
Look, you describe N&Z as “ultimately incredibly simple” … so how about you share that simplicity with us? I mean if it’s all that simple … why the wait?
You say you have “read and understood” N&Z. There is an easy test to determine if that statement is true—explain the incredibly simple N&Z theory that you say you understand.
So no, I fear you don’t have time, Lucy. You say you understand the N&Z theory now, this moment. You say now, this moment, you know how “incredibly simple” it is … so no need to wait ’til next week, how about you give us the elevator speech now, this moment, so you can see if you do understand it? Don’t put it off until you collect the “stunning high-quality evidence”, that only does any good after we understand the theory. Hit us with the elevator speech, we’re tough, we can take it.
The elevator speech is only partly so we can see if you understand it, Lucy. Mostly, it’s so you can see if you understand it …
My very best to you,
w.

32. markus says:

“As this is a clear violation of conservation of energy, the proof by contradiction that the Jelbring hypothesis violates the conservation of energy is complete”.
Can somebody please conceive this fact; Energy cabn be also employed, not just conserved.
Add kinetic energy to matter and the E does not equal mc/2.

33. Dr. Brown says that your “column of gas” will have the same temperature at the top as at the bottom, due to equal numbers of molecules with identical kinetic energy moving each way between adjacent thin “slices”. So those adjacent “slices” have equal overall kinetic energy and MB distribution, and therefore equal temperature. In that case they must also have equal numbers of molecules, and so the two slices must have equal pressure. If two adjacent thin slices have the same pressure, then the whole column has the same pressure. Extend the column or cylinder to TOA and you have a mechanism to lose the top layer to space fairly rapidly, and by logical extension, the whole atmosphere.. Some disconnect with reality here?

34. Willis Eschenbach says:

Bill Illis says:
January 19, 2012 at 5:50 pm

What about the gas giant planets? Jupiter at 99% hydrogen and helium has had about 4.6 billion years to become isothermic. Yet the lowest gas/liquified gas/metallic hydrogen temperatures are 35,700K and the top of the atmosphere is only 165K.

Bill, the isothermal condition only obtains when there is no energy entering or leaving the system, as is the case with Jelbrings thought experiment about his theory. Obviously, this is not the case for any of the planets. As a result, we would not expect Jupiter to be isothermal.
w.

35. We know that gravity exists but not one acedemic has managed to explain with any confidence why our boots are attracted to the Earth’s core.

36. markus says:

“”The explain the incredibly simple N&Z theory that you say you understand””.
The kinetic energy of mass is the mechanism that enhances its employment of energy.
But it is explained Willis, so fully by N&K, it turned my lights on, and what a brilliant sight it is to see.

37. Walter says:

All sounds like my first year university Physics lectures.
Perhaps a few more Physicists need to read and understand and comment.
Where’s Richard Feynman when we really need him?

38. GeoLurking says:

@Josh C and ShrNfr
Ref Earth’s Heat
Don’t forget that we still quite a bit left from the accretion of the planet.

39. Willis Eschenbach wrote:
“at thermal equilibrium, the average energy per volume is the same from top to bottom, with every cubic metre having the same total energy. To do that, the gas needs to be isothermal, with the same temperature in every part.”
No it is not, equipartition states that temperature is proportional to the internal energy per molecule. Energy is an extensive property, temperature intensive.

40. markus says:

“Zac says:
January 19, 2012 at 6:01 pm
We know that gravity exists but not one acedemic has managed to explain with any confidence why our boots are attracted to the Earth’s core”.
They can now. Wrong way up we are.
Its not that your boots are attracted to the earths core, it’s that your boots are attracted less to the earths core, because you have more kinetic (employed) energy. As is matter with more kinetic energy above you, like gas.
Quite simple really.

41. Willis Eschenbach says:

I had made the following argument above:

tallbloke says:
January 19, 2012 at 4:34 pm

… The Second Law of Thermodynamics states that “in all energy exchanges, if no energy enters or leaves the system, the potential energy of the state will always be less than that of the initial state.”

Hans Jelbring, on the other hand, proposes a model earth with an impenetrable shell around it that does not allow energy to enter or leave the system, op. cit.:

A simplified model of Earth will be considered. The model planet does not rotate. It neither receives solar radiation nor emits infrared radiation into space.

In other words, no energy can get into or out of Jelbring’s system.
It seems to me that you just proved that Jelbring’s hypothesis can’t work, Tallbloke. If the potential energy of the state inside the shell can only move to where it is less than the initial state, as your quote clearly states … then how can the gravity possibly separate a low-energy, isothermal atmosphere into a higher energy state of cold at the top and warm at the bottom?
My best regards to you,
w.

I realized after posting this that some people might say “well, maybe the isothermal case is the high energy state”. There’s an easy way to settle that.
If an energetically isolated system is in its lowest energy state, it cannot perform work.
If the isolated atmosphere in Jelbring’s thought experiment is warm at the bottom and cold at the top, I can stick a thermocouple into it and use the temperature differential to generate electricity to perform work.
Therefore, the isothermal state (same temperature everywhere) is the lower of the two energy states, since I cannot use it to do work.
As Tallbloke points out, the second law says an isolated system can only move towards a lower energy state. That means Jelbring’s thought experiment must inexorably move towards the isothermal condition as its equilibrium state.
Since Jelbring claims an adiabatic state will obtain at equilibrium, his hypothesis is falsified.
w.

42. Bill Illis says:

100 kg of gas 100 kms from Earth will have 98,000,000 less joules of energy than 100 kg of gas at the surface.
Gravitation potential energy actually turns into real thermal energy for a mass that is falling through a gravity field or objects with mass that are closer/farther from the centre of the gravity field.
GPE = Mass * Gravity * Height
Without this (albeit very unnatural effect to us but nevertheless real effect in the real universe) there would be no stars or galaxies anywhere and there would no elements beyond hydrogen, helium and tiny amount of Lithium and there would no us. The universe is made up of many different types of energy beyond photonic EM radiation. There is the strong force, the weak force, gravity and dark energy in addition to the electro-magnetic force.
If we are going to just accept every “settled scientific fact” about radiation theory, then we might as well all be running climate models. If they don’t work, then there is a reason. One is, they do not consider everything that is actually happening (in the quantum world, in the real universe).

43. ferd berple says:

Willis Eschenbach says:
January 19, 2012 at 5:54 pm
Lucy, thank you for your comment, but time is what you don’t have.
That is the same argument used by the cap and trade shills to try and force people to agree without due taking time for due diligence. Buy now before it is too late.
Temperatures have leveled. Sea levels have stabilized. CO2 has not. These events contradict GHG theory predictions, which in science is a strong indication the GHG theory is wrong.
It is as though Einstein predicted that gravity would bend light, and when light was measured it was found not to bend. So, then Einstein proposed a new aerosol particle to explain why gravity did not bend light as predicted, but would bend light in the future.
There is plenty of time to review the science and find out why the GHG predictions failed.

44. Willis Eschenbach says:
January 19, 2012 at 4:58 pm
“…then how can the gravity possibly separate a low-energy, isothermal atmosphere into a higher energy state of cold at the top and warm at the bottom?
How do you know that the “cold at the top and warm at the bottom” state has a higher energy?

45. Isothermal is just that isothermal, no change in temperature with altitude. The energy contained per unit volume would be greater at altitude than at the surface if fewer molecules occupied that volume. So here is an interesting thought experiment.
To be isothermal, the atmosphere would require perfect insulation. The number of collisions of molecules per unit volume at the surface would be the same as the number of collisions per unit volume at the top of the atmosphere. There would be no lapse rate. The density of the atmosphere would be greater, but there would still be a top of the atmosphere. How high would that be?
Now, if gravity increased, the height of the TOA would decrease. If the atmosphere was perfectly insulated, the temperature of the volume would increase due to compression. There is still no lapse rate, the atmosphere is still isothermal. The number of collisions per unit volume increase.
Now let’s let energy flow from the surface out of the TOA. Unless the atmosphere is perfectly conductive or perfectly transparent to radiant flow, energy will be lost to the atmosphere. With the additional energy, the atmosphere expands, creating a lapse rate, temperature decreases with altitude. Since energy must be conserved, the total energy of the atmosphere must remain the same if the average energy of the atmosphere is to be maintained, unless we add energy. Now the “potential temperature” of the parcel of air at altitude would equal the true temperature of the parcel of air at the surface.
Now that we have a lapse rate and the total energy of the atmosphere fixed since we have not added energy. If the surface layer of the atmosphere warms by 33C then the TOA decreases by 33C. There is a 66C difference in temperature between the surface and the TOA, which is the tropopause. Add sunlight and we have the stratosphere and a new TOA.
Manabe knows that and his estimate for CO2 forcing is half of Hansen’s. Trenberth doesn’t know that, or at least won’t admit that, so his cartoons are meaningless.
CO2 has an impact, just not as much as estimated by people that confuse the tropopause with the surface.

46. richard
“The problem is that GHGs and back radiation does not explain the vertical temperature of the atmosphere. ”
The vertical temperature differential is a requirement for the GHG effect. You’ve not understood why GHGs cause the surface to cool less rapidily than it would otherwise.
Simply. If the upper altitudes were not colder, then GHGs wouldnt have the effect they do.
More GHGs means the earth radiates from a higher elevation.
If that higher elevation is cooler, then the surface must “warm” or cool less rapidily.
Lapse rate is a requirement for the GHG effect to take place.

47. Robt319 says:

Hi,
I have some questions and some observations but as I am not as smart as some please excuse my mistakes.
Due to the spherical nature of our planet, any column of air will not be parallel sided but will be trumpet shaped and the volume will not be linear. Does this effect your equilibrium of energy?
Your statement that a column of air will stratify in a gravity field is observed on earth and I believe that this temperature gradient is in part due to the effect of gravity. Does not the ideal gas law have some application here? However, as we know, the atmosphere is very complicated and probably cannot be described so simply.
The heat engine Dr Brown describes in his proof by contradiction sounds to me like the description of a thunder storm and I personally have observed many of those. If we could harness the power of thunder storms and hurricanes we could indeed power our cities but of course our atmosphere also has other sources of energy, namely the sun. Does Dr Brown disprove the theory or add weight to it?
I am not trying to suggest that anything is right or wrong but the idea that the lower atmosphere is warmed by gravitational pressure from the air above it makes sense to me.

48. ShrNfr says:
January 19, 2012 at 4:03 pm
There are actually at least 3 intrinsic heat sources for the earth:
1) fission of radionuclides
2) primordial heat from earth’s formation, and the impact that created the moon, or other impacts
3) flexion friction from gravity interactions, especially from the moon
Chemical oxidation heat is mostly externally provided and driven (photosynthetic oxidation of carbon, oxygen being provided by conversion of nitrogen by cosmic and solar radiation, etc.)

49. Hoser says:

Gas molecules don’t travel in straight lines very far. They collide. Energy in these molecules is spread in a distribution described by temperature, across various degrees of freedom (1/2 kT).
Thermal conduction in the Earth seems to be very slow. There are temperature gradients below ground. Caves near the surface seem to have a temperature roughly equal to the average yearly temperature. Temperatures under ground increase with greater depth. Could the heat of radioactive decay make much difference at the surface? Perhaps it’s the old chicken and egg dilemma.
It seems a significant contribution to the Earth having an elevated temperature compared to a black body is the delay in reradiating absorbed light from the sun. The surface warms and some of that energy works its way deep into the ground, or into water below the surface. There is heat capacity, heat conduction, and fluid mixing in the oceans all moving absorbed energy to and from the surface where it might be radiated back to space. The Earth is a heat sink with poor thermal conduction characteristics. If the Earth absorbs light more efficiently than it radiates, then the surface temperature must rise before equilibrium is reached. That higher temperature is thermal energy that can be transported deeper into the Earth. It will take time to penetrate, and it will take time to rise back up to the surface after the sun sets.
If some of the daily energy is retained and not radiated at night, then the Earth’s temperature rises. A glacier has similar properties. Eventually all of the snow that falls on a mountain melts, but if some of the snow never melts during the summer, a glacier will form. The length depends on various parameters like snowfall, but eventually all of the snow melts. The glacier length stabilizes when the rate of snowfall balances the rate of melting. If some of the heat absorbed during the day is not reradiated, then the surface the next day will start out warmer. The average surface temperature will rise until the total amount of energy radiated over 24 hours equals the total amount absorbed during the day.
The atmosphere can pick up thermal energy by conduction and move it to cooler places. The atmosphere also has its own heat capacity. However, there is no way in hell that our atmosphere retained excess heat due to some hypothetical compression event over 4 billion years ago.

50. Joe Born says:

If you reduce the number of molecules to a fairly small number, you can see that Willis’s argument, beguiling as it is, is wrong. Consider a single-molecule system, for example. Does anyone doubt that the molecule’s translational kinetic energy is greater when it is lower in the gravitational field than when it is higher? Does that reverse relationship disappear when a second molecule is added?
As the number of molecules gets large, the system approaches isothermic. But a (very small) lapse rate persists.

51. jae says:

DAMMIT, WILLIS:
PLEASE ADDRESS THE EMPIRICAL EVIDENCE, WHICH WILL ULTIMATELY RESOLVE THIS ARGUMENT! WHY DO YOU REFUSE TO DO THIS?
[Moderator’s suggestion: If you didn’t YELL at him maybe more would be accomplished? Maybe? -REP]

52. I think that you had it right to begin with – the molecules move faster down low. That means temperature is higher down low. The fact that energy density is constant is a red herring.

53. Dougmanxx says:

I am a semanticist at heart. I read with interest these posts and wonder about two little words: “at equilibrium”. I suspect these theories are thinking about something that doesn’t actually exist in the “Real World”, like so many thought experiments I see from so many very learned and intelligent people.This begs me to ask several questions:
1) Is the atmosphere of the Earth “at equilibrium”?
2)If the atmosphere of the Earth is not “at equilibrium”, does this discussion have any meaning, other than as a diverting thought experiment?
3)If the atmosphere of the Earth is not “at equilibrium”, how will it behave?
Like much climatic, I suspect we are undone by our “Human” view of things.

54. u.k.(us) says:

IMHO,
When, Dr. Robert Brown speaks, people should shut up and listen.

55. David says:

A gentle reminder of the core issue raised by Willis: It seems to me that many posts are injecting unwanted complexities. While it is true that the Earth includes a large body of water, rotates in a 24 hour period, has a core that produces a (small) amount of energy, and so on and so forth, the question to be resolved is the behaviour of a column of “air” – actually any gas – in a gravity field, particularly its change in temperature (if any) with altitude.
To resolve this requires the question to be formulated as simply as possible. So to understand how gravity affects temperature distribution we ignore – for the time being – anything extraneous. No sun, no rotation of the Earth, no surface or sub-surface effects. Simply a column of gas in a gravity field. Nothing more.
I appreciate the effort many have put into their posts, and many are very interesting. But first let us understand how this works in the simplest manner possible.

56. Ed_B says:

David says:
January 19, 2012 at 5:21 pm
“The air moving up and down exchanges potential energy (PE) for kinetic energy (KE). The air moving down loses PE but gains KE, and vice versa for the air moving up. A higher KE means a higher temperature, a lower KE means a lower temperature. So the air moving down increases in temperature (KE), while the air moving up decreases in temperature (KE). This will maintain the adiabatic lapse rate, warmer air at the bottom of the column and cooler air at the top.”
I agree with this. Respectfully, Willis is wrong.

57. Rob Dawg says:

Gravity fields are not acceleration fields. In uniform acceleration fields the temperatures are indeed uniform. For a column of material In a gravity field to be of uniform temperature the column would need to be walled radially from the gravity point source.

58. markus says:

Dear Mr Willis Eschenbach;
As you have [SNIP: Markus, sorry, but this sort of stuff contributes nothing to the discussion. You can make this sort of comment AFTER a cogent debunking. Please. -REP]

59. Werner Brozek says:

If we had a single pane of glass and the temperature outside was 10 degrees and it was 20 degrees inside, then the temperature within the pane would vary linearly from 10 to 20 degrees across the width of the pane. Right? Now let us pretend we had a 10 kilometre long solid copper tube in the form of a vertical pole that was totally insulated except that the bottom 10 metres was in asphalt at 30 degrees C and the top 10 metres and was exposed to air at -50 degrees C. Then you would automatically have a temperature gradient of 8 degrees C per kilometre. How is this fundamentally different from what really happens with air? If the sun heats the surface and outer space is cold, you automatically get a temperature gradient without resorting to work done by increasing pressures.

60. I take your kilometer’s tall cylinder of atmosphere in thermal equilibrium and flip it over, like flipping an hour glass. It involved no input of work as its height did not change, so the column’s energy remains constant. But now the gas at temp T that was at the top has been wildly compressed, making it much, much hotter, while the gas at temp T that was at the bottom has been expanded, making it much, much colder. If you let it get anywhere close to thermal equilibrium I’m going to flip it over again, and since I’m not putting in any work, I can do this all day, continuously forcing your air column back to the dry adiabatic lapse rate as I sip a margarita.
I love doing jobs that don’t involve an input of work and constantly overturn an idealized thermal equilibrium, because it’s just that easy.

61. KevinK says:

Willis, thanks, that is a beautiful picture of a perpetual motion machine.
When I was a lad with a crude workshop I did play for a while with the PM notion. My version was powering an air turbine with the exhaust from a compressed gas source. Of course the the turbine was going to compress even MORE gas and the turbine would produce lots of free energy.
Then I went to engineering school…..
One thing I learned in school was that if something works there will be tens or hundreds of people using it. For example the IC engine, the airplane, the integrated circuit, and (not for much longer sadly, see the recent news about Kodak) photographic emulsions on flexible roll film.
So I ask myself, if the Greenhouse Gas Effect is REAL (still in question it seems after these many decades) WHY is it that NOBODY has figured out how to apply it to any practical problem and solve, or at least ameliorate said problem ?????
Think about it for a second, there are lots of very obscure physical effects that have practical applications. For example, the Bernoulli effect is what makes a plane fly (although there is still some debate; does the effect “suck” the plane upwards, or does it “push” the plane upwards, this one seems like tomato .vs. thamato to me). The Peltier effect has been used for decades to cool electronic devices and has lately been applied to drink coolers.
It sure seems that once a physical effect is observed and characterized some sharp engineers find a way to apply it to solve a problem.
So why is it that after decades no sharp engineer has figured out how to apply the Greenhouse Effect to solve any problem, like maybe using the effect to create “net energy gains” in the insulation surrounding a building, that would sure reduce energy usage ???
I see a few possibilities;
1) Engineers are dumber than climate scientists, seems unlikely, some are probably dumber, but I bet at least a few are smarter.
2) There are a dearth of practical problems to be solved, seems unlikely, there always seems to be lots of problems to be solved, like how do we feed everybody and keep them warm. Or how do we allow folks to have fun on a floating cruise ship without letting an incompetent skipper rip a hole in the side by driving it over rocks and “catching” one in the hull, OK we have some more work to do there….
3) Maybe the Greenhouse Effect does not exist, or it exists, but does not provide any “net energy gains” or produce a “higher equilibrium temperature” as claimed ?
Personally, I’m betting on choice #3 and giving odds of several Million to One.
I have not yet evaluated any of the “gravity caused” theories others have suggested and you are discussing, and they may in fact have some merit. But I am convinced that the ”Greenhouse Effect” hypothesis is a modern version of the Perpetual Motion Machine. BTW you are not supposed to be granted a patent on PM machines, and I see nobody trying to patent the “Greenhouse Effect” or applications of if, surely somebody would have tried to lock up all the potential business opportunities if the “effect” really existed as promised ???
Cheers, Kevin.

62. Jean Parisot says:

Somewhat off topic, has anyone built up an error budget for the AGW hypothesis? Not just how skill(less) the models are, but from a mearsurement perspective.
Our understanding of the historic record has error bars that dwarf the analysis. Our recent data has significant error. The spatial error is enormous.
What is all of this hysteria actually saying? We think a 2° rise is too fast, but the historic record can’t be resolved to that fine a point; and that 2° rise is based on models that don’t replicate the record fed with data widely dispersed, inconsistent measurements of fluctuating weather.

63. Jeremy says:

Gravity has NO AFFECT ON TEMPERATURE.
How many times must it be said.
You people are reading science fiction.
You have to do WORK to create a change in temperature – this is basic thermodynamics!!!!
If an object falls in a gravitational field then potential energy will be converted to kinetic energy which will create heat. However a stable column of air in equilibrium does not create any energy or heat.
This is so so so basic that I am afraid I may have to give up this website altogether in disgust.

64. crosspatch says:

Imagine you have a tube of air 1km long. Now instead of being a tube, you basically turn it onto a cone. Lets say the bottom of the tube represents 1/10,000 of the surface of the Earth, and the top represents 1/10,000 of the “surface” of an imaginary sphere at 1km altitude. This is why I said I would model the atmosphere as a series of concentric spheres representing conditions at the altitude of each sphere. Now, temperature and heat. At molecule at the ground might be 100F and a molecule at 40km might be 100F but there are far fewer of them at 40km. So if you stick your thermometer out the window of the bazillionth floor at 40km altitude, far fewer molecules will strike your thermometer and transfer heat to it. So your thermometer will cool until it reaches an equilibrium where the heat it is radiating is equal to the heat it is receiving. So the temperature of the molecules can be the same (100F) but there is less heat per given amount of space because there are fewer molecules.

65. Luther Wu says:

Equilibrium of the atmosphere doesn’t exist. As can be seen in this thread, just trying to understand the climate in even the simplest terms is a daunting task.
Topologists long ago proved that the wind will always blow somewhere…
right after they mistook their donuts for their coffee cups.

66. @ David says:
January 19, 2012 at 7:20 pm

From what I’m understanding, I agree.
However, I can’t help but wondering what would happen, keeping the extraneous items out as you said – “no sun, no rotation of the Earth, no surface or sub-surface effects. Simply a column of gas in a gravity field. Nothing more” out, except in a situation where the gravity isn’t constant. Wouldn’t, in that case, we have a continuously moving gas due to the changing gravity? Would we then see heat, energy, or work being “created” by the fluctuating gravity?
Just wondering.

67. AusieDan says:

Willis,
You keep asking for an elevator speach supporting the N&Z analysis.
Here is my attempt.
(1) any worthwhile theory should describe reality or it is worthless and should be discarded.
(2) When you make due allowance for differences in their distances from the sun, the temperature of Mercury, relative to Venus, is too low to be explained by the greenhouse theory.
(3) However this is very closely explained by their different atmospheric pressures at the surface.
(4) That is also true for other bodies in the solar system.
(5) That in turn suggests that the various laws on physics mentioned in this thread, while themselves highly likely to be true, do not interact in the manner that has been outlined by people critical of the two unpublished N&Z (20110, 2012) papers.
I really do not think that this arguement will be settled using theoretical “thought” experiments. These remind me in so many ways of the best work of the IPCC.

68. AusieDan says:

We need a theory to explain why the surface temperature of the various solar bodies can be derived as a function of distance from the sun (solar radiance) plus near surface atmospheric pressure.
N&Z have provided their theory.
The task of critics is now to come up with better, more economical (Occham’s Razor) theories.
As Lucy Skywalker has said – this is a game changer.
the game HAS changed.
We must now all respond to the new paradigm.

69. richard verney says:

Jeremy says:
January 19, 2012 at 7:52 pm
///////////////////
Jeremy
Just three quick questions.
1. How much work is involved in the creation of the diurnal/atmospheric bulge?
2. How much work is involved in the moving of the tides?
3. Are not the same processes that are involved in moving the tides also at work on the atmosphere but not so readily apparent to an Earth boud observer since he cannot see the ebb and flow of the atmosphere as it is sublected to the gravitaional forces of the celestrial bodies?
The gravitational forces being exerted on the atmosphere are not constant. The atmosphere is never in equalibrium.
Perhaps you will answer my questions before departing this web site.

70. Stephen Wilde says:

In the absence of an external energy source the column would indeed become isothermal.
Temperature at both top and bottom would be the same despite the higher energy content per unit volume at the bottom.
Mass is simply a form of energy so a denser mass per unit volume contains more energy but it does not follow that it has a higher temperature than a less dense unit of volumre.
Temperature is simply a measure of kinetic or vibrational energy and molecules can have the same averaged kinetic energy in both a dense and a less dense unit of volume.
Gravity just primes the system by placing greater density of molecules at the bottom of the column. It does not provide any heat or kinetic energy in itself.
If an external energy source is then switched on then the kinetic response to that energy input is density dependent and so the temperature gradient with density then appears.
More molecules per unit volume will convert a larger proportion of the incoming radiative energy into kinetic form and it is kinetic energy that is refected in a higher temperature.
Furthermore higher density involves more collisional activity due to closer packing of the molecules so that kinetic energy stays in kinetic form for longer whilst it is bounced to and fro between molecules before eventually being released in the form of outgoing longwave.
The more incoming radiation that is converted to kinetic energy per unit volume AND the longer it stays in kinetic form the higher the temperature will become.
The adiabatic temperature gradient is therefore a consequence of gravity induced pressure PLUS uneven energy distribution (more molecules per unit volume) PLUS incoming radiation.
ALL the components must be in place at the same time to produce the temperature gradient.
THEN the entire structure of the planetary atmosphere is effectively forced to adjust itself to provide the most efficient mix of energy transfer mechanisms both radiative and non radiative so as to maintain that adiabatic temperature gradient.
Radiative processes only perform a mopping up function. In so far as non radiative processes fail to return the system to that adiabatic lapse rate then radiative processes step in to make up the difference.
The S – B equations do not deal with the non radiative processes.
The final oucome in terms of atmospheric structure can become highly complex and that is where composition becomes relevant and why no planet with an atmosphere matches the S – B equations.

71. Quark says:

Imagine a glass tube 100 miles tall reaching from the surface of the earth to outer space. Insert the base of the tube in concrete and then fill it with Coca-Cola or some other carbonated beverage. Now add peanuts at the top and watch what happens. At first the peanuts sink but as the fall, they gather bubbles which slows their descent until …..
LOL.
Sorry. But Jeremy is right. This discussion is almost totally nuts.

72. richard verney says:

KevinK says:
January 19, 2012 at 7:42 pm
////////////////////
Kevin
I have made this point to Willis on a number of occassions and it has always been met with deadly silence.
Why are we seeking to exploit solar energy by way of PV cells when this has obvious drawbacks such as sunlight is not received at night or when cloudy. Trenberth suggests that on average solar power is just 184 w per sq m. Why are we not exploiting backradiation or at any rate researching its use when it is claimed to be in the order of 333 w per sq m come rain or shine 24/7? If this was truly a souce of energy capable of doing sensible work, we would be exploiting it since it would cure over night the world’s energy needs. Something is amiss here and it is probably that physists employed by energy companies or at the cutting edge of research do not consider it a source of sensible work.

73. KevinK says:

Richard, yes I also get silence from Willis regarding any of my comments. I think that this is his loss…
I still think that if the “greenhouse effect” had any merit a whole bunch of engineers would have JUMPED on it a long time ago. BTW I am an engineer and I always JUMP on any “effect” that helps me solve a problem.
Cheers, Kevin.

74. Willis Eschenbach says:

ferd berple says:
January 19, 2012 at 6:34 pm

… Temperatures have leveled. Sea levels have stabilized. CO2 has not. These events contradict GHG theory predictions, which in science is a strong indication the GHG theory is wrong.

Thanks, ferd. I come to a very different conclusion from the same facts. I say that the greenhouse effect has done the heavy lifting of bringing us to our warm current temperature. At the current equilibrium condition, however, the various governing systems have come fully into effect, keeping the earth from warming any further. These mechanisms include the daily cycle of thunderstorms in the tropics, the annual swing of clouds which warm the planet when it is cold, and cool it when it is warm, and the multi-year swing of the Nino/Nina cycles.
This does not mean that GHGs have no effects. It means that at the equilibrium condition, the minor changes in GHGs are totally swamped by the effects of the clouds and other governing mechanisms.
All the best,
w.

75. Willis,
I was in the same boat as you, thinking that the equilibrium temperature profile of an insulated column of air would be warmer at the bottom than the top. Like you, I changed my mind.
I discusses the topic with a few bright physicists. We bandied back and forth several ideas. There are a few convincing (but wrong) arguments that a lapse rate is the expected result. Eventually we concluded that the equilibrium profile must indeed to isothermal, because the arguments for that were more convincing (and right).
The simplest and most convincing argument ended up being your same perpetual motion approach. You could run an insulated copper bar from bottom to top. This bar does not have the lapse rate effect. (Or use another gas that would have a different lapse rate because it has a different heat capacity). The copper should have the same temperature at top and bottom. If the gas had a different temperature, would could use this temperature difference to continually run the sort of heat engine you suggested.
And that is how theoretical science is supposed to work. You come up with a couple different ideas about the some new situation. You apply fundamental, laboratory-tested principles and discuss it with others. When several different people who understand the science agree, then you have your conclusion.
PS A “back of the envelope” calculation suggests the “time constant” for this process would be weeks. Reaching something close to uniform temperature could takes months. But in the real world, there would be other processes to remix the air long before that.
PPS. This whole gedanken experiment was, of course, predicated on perfect insulation and a constant temperature at the bottom. The same “back of the envelope” calculation suggests that heat flows involved in conduction are less and 1 mW/m^2. Even a tiny amount of GHG at the top of the atmosphere would radiate a 1,000 times more energy, meaning that conduction would never actually achieve a uniform profile.

76. Willis Eschenbach says:

jae says:
January 19, 2012 at 7:05 pm

DAMMIT, WILLIS:
PLEASE ADDRESS THE EMPIRICAL EVIDENCE, WHICH WILL ULTIMATELY RESOLVE THIS ARGUMENT! WHY DO YOU REFUSE TO DO THIS?
[Moderator’s suggestion: If you didn’t YELL at him maybe more would be accomplished? Maybe? -REP]

jae, I fear I don’t have a clue which “empirical evidence” you are speaking of. If it has to do with the N&Z hypothesis, I don’t understand the hypothesis so “evidence” means nothing. Let me know which evidence and which theory you’re talking about.
More light and less heat would help here.
w.

77. Willis Eschenbach says:

David says:
January 19, 2012 at 7:07 pm

Willis, do you have a rebuttal or reply to my post http://wattsupwiththat.com/2012/01/19/perpetuum-mobile/#comment-870067?

David, your rebuttal is to the argument made by Dr. Brown, and I don’t want to explain his argument more than I’ve done. For an answer, you should post it on his thread, the link is at the top.
Many thanks,
w.

78. Willis Eschenbach says:

Dougmanxx says:
January 19, 2012 at 7:10 pm

I am a semanticist at heart. I read with interest these posts and wonder about two little words: “at equilibrium”. I suspect these theories are thinking about something that doesn’t actually exist in the “Real World”, like so many thought experiments I see from so many very learned and intelligent people.

To the contrary. Thermal equilibrium simply means that the objects have stopped exchanging energy because they are at the same temperature. This happens all the time.
w.

79. gbaikie says:

“• If left undisturbed in a gravity field, a tall container of air will stratify vertically, with the coolest air at the top and the warmest air at the bottom.
• This also is happening with the Earth’s atmosphere.
• Since the top of the atmosphere cannot be below a certain temperature, and the lower atmosphere must be a certain amount warmer than the upper, this warms the lower atmosphere and thus the planetary surface to a much higher temperature than it would be in the absence of the atmosphere.”
Strange as seems I would say it’s it’s true. We are assuming the gas that we talking about can’t freeze or liquify.
Nitrogen in near vacuum pressure can be close to absolute zero. And Helium:
“All known liquids, except liquid helium, freeze when the temperature is lowered enough. Liquid helium remains liquid at atmospheric pressure even at absolute zero, and can be solidified only under pressure.”
Liquid helium: Boiling point at 1 atm: 4.2 K 3.2 K
http://en.wikipedia.org/wiki/Liquid_helium
So certainly true if you are talking about a helium atmosphere.
Of course to have gravity you need mass- something which is giving 1/10th of gee will have internal heat.
Question is would work with artificial gravity.
I think there some thought experiment which says under certain you can’t tell the differences between acceleration and gravity, perhaps this would be a way to tell the difference, and maybe not.
• This is the cause of what we erroneously refer to as the “greenhouse effect””
Hmm, don’t think this explains everything in regards to the “greenhouse effect”.
If include the sun’s energy, the heat capacity of atmosphere, water vapor, clouds, ocean temperature, and land temperature, then yeah, most of the greenhouse effect.
And I don’t think it explain stratosphere and higher.

80. Willis Eschenbach says:

George Turner says:
January 19, 2012 at 7:34 pm

I take your kilometer’s tall cylinder of atmosphere in thermal equilibrium and flip it over, like flipping an hour glass. It involved no input of work as its height did not change, so the column’s energy remains constant.

You have not allowed for the fact that the atmosphere in the cylinder is mostly at the bottom. As a result, you have to move much more air up than down when you flip it. So it does involve a large input of work, despite the fact that its height did not change.
w.

81. mondo says:

A question about the diameter of the column of air extending upwards 1km. If the column were small diameter (say 5m across at ground level – expanding as it rises) would we not get different conditions/events than if it were, say, 1 km diameter? At some point, won’t we see convective effects happening? With hot air rising as it would in a hot air balloon? As Willis has so convincingly explained with his thunderstorm arguments (or did I miss something somewhere?).
And, further demonstrating my lack of knowledge, if warmer air rises due to convective effects, how come we notice that air temperatures are (generally) warmer at lower altitudes? Is that to do with the relatively greater air density at surface than at altitude.
Clearly I must do more reading to keep up.

82. the universe is a perpetual motion system, expanding and contracting simultaneously in patterned ways, ad infinitum.
the universe is matter and space. temperature is associated with matter. it seems that a critical amount of matter determins black hole versus supernova outcomes for astronomical bodies.
what is the trigger for a big bang ? an accumulation of matter.
given that time is a measure, we could describe the life cycle of big bang as how many years ?
my point is that entropy is the normal condition.
more specific phenomena are contextual. our entropy is affected by local conditions, but in the end physical constructions return to matter and space.
my miniscule understanding of the topic under question favours the idea of gravity increasing temperature. where are the hottest places in our environments ? the centres of our astronomical bodies ?
ergo gravity wins up to the point of bigbang initiation, which may well be another gravitational effect.
of course I’m brain-sailing, surmising, and thinking aloud.

83. I have a follow-up thought experiment to my previous comment.
If flipping the air column upside down doesn’t require an input of work and returns the column to the dry adiabatic lapse rate, then the dry adiabatic lapse rate must be the column’s thermal equilibrium because a system cannot be shifted from thermal equilibrium without an input of work.
If the adiabatic lapse rate is the thermal equilibrium then it should be impossible to devise a heat engine driven by a column of air whose temperature varies with the adiabatic lapse rate. If the isothermal condition is the thermal equilibrium then the same should apply, because a system in thermal equilibrium can’t drive a heat engine.
If I take a tall column of isothermal air in a gravitational field and exchange a pair of parcels from top to bottom, the descending parsel warms up and the ascending parcel cools down, with no change in energy and no net work. Yet in their new positions both these parcels have a large delta T relative to the surrounding air, and that delta T can drive a heat engine such as a Stirling cycle.
If I try moving parcels within a column whose temperature follows the adiabatic lapse rate, each parcel always stays at the same temperature as the surrounding air, so I cannot drive a heat engine. From that I conclude that an isothermal column of air in a gravitational field is not in thermal equilibrium, and a column of air at the adiabatic lapse rate is.
So if the column of air is isothermal, I can drive lots of little heat engines until it reaches the adiabatic lapse rate, after which I can extract no more energy from the system.
On caveat is that if the system is at the adiabatic lapse rate then the bottom air is warmer, and thus less dense, raising the center of mass of the entire column in slightly increasing its potential energy, so perhaps flipping the column does involve an input of work. Perhaps a more detailed analysis would take this into account and provide a slightly shifted equilibrium point.

84. Willis Eschenbach says:

Jeremy says:
January 19, 2012 at 7:52 pm

Gravity has NO AFFECT ON TEMPERATURE.
How many times must it be said.
You people are reading science fiction.
You have to do WORK to create a change in temperature – this is basic thermodynamics!!!!
If an object falls in a gravitational field then potential energy will be converted to kinetic energy which will create heat. However a stable column of air in equilibrium does not create any energy or heat.
This is so so so basic that I am afraid I may have to give up this website altogether in disgust.

Thanks, Jeremy. You are a hundred percent correct, gravity can’t do ongoing work to change the temperature. And yes, there’s a heap of folks that are not clear about that, I wasn’t until recently.
One of the things that happens here is that we try to provide information and informed discussion about basic science, for me (as you can see from my story above) as well as for others. Every blog has lots of folks who are in need of this. Most don’t even deal with it.
Now, since the proponents of these “gravito-thermal” theories have been gaining some prominence and some traction on the blogosphere, I’m trying to provide a counterweight of science. When you go out to battle the forces of scientific fantasy, there will be (as you have observed) lots of folks that don’t get the basics.
If you are fighting basic ignorance of science, you will be deluged with ignorant people. Not much I can do but just keep putting the facts out there.
Certainly there are a host of much more sophisticated threads, and those tend to attract a more scientifically literate commenter. But when you are discussing “gravito-thermal” theories …
So you could stick to the posts that don’t even mention gravity. Or you could stick around and try to explain it. If so, prepare for frustration. In any case, I can only agree with your statements, thanks for your post.
w.

85. Willis Eschenbach says:

AusieDan says:
January 19, 2012 at 8:06 pm

Willis,
You keep asking for an elevator speach supporting the N&Z analysis.
Here is my attempt.

(1) any worthwhile theory should describe reality or it is worthless and should be discarded.
(2) When you make due allowance for differences in their distances from the sun, the temperature of Mercury, relative to Venus, is too low to be explained by the greenhouse theory.
(3) However this is very closely explained by their different atmospheric pressures at the surface.
(4) That is also true for other bodies in the solar system.
(5) That in turn suggests that the various laws on physics mentioned in this thread, while themselves highly likely to be true, do not interact in the manner that has been outlined by people critical of the two unpublished N&Z (20110, 2012) pape

rs.

Thanks, Dan. The problem with your elevator speech is that nowhere does it say how the N&Z effect actually works, which is the point of the elevator speech.
w.

86. Willis Eschenbach says:

Quark says:
January 19, 2012 at 8:35 pm

Imagine a glass tube 100 miles tall reaching from the surface of the earth to outer space. Insert the base of the tube in concrete and then fill it with Coca-Cola or some other carbonated beverage. Now add peanuts at the top and watch what happens. At first the peanuts sink but as the fall, they gather bubbles which slows their descent until …..
LOL.
Sorry. But Jeremy is right. This discussion is almost totally nuts.

If you don’t like it, Quark, then lead, follow, or get out of the way … but just complaining does nothing.
Many questions have been settled or elucidated by thought experiments. Einstein was very fond of them. Your idea that they mean nothing ignores a long history of their use in science.
w.

87. gbaikie says:

“Temperature at both top and bottom would be the same despite the higher energy content per unit volume at the bottom.”
The “higher energy content” seems to mean it’s hotter.
It seems the gas molecules would all have same average velocity- with exception that faster molecules would tend to be higher and slow molecules would be lower. This tendency- depends upon the amount of gravity- 10 gees would more of tendency than 1 gee. But this means more fast molecules could found and average speed isn’t different, the gravity sort them more. If follow a molecule it tends to stay lower, and spend less time higher.
Or the gas molecules are always varying velocities, the velocity is random, but is averaged by the zillion of molecules. If heads is faster, molecules with 10 heads in a row are tend to be higher, those with 10 tails in row tend to be lower.
In gravity field the average molecule speed will lower in the higher density.
Put 1 cubic meter of 1 atm gas, into another 1 cubic meter of 1 atm gas- doubles pressure to 2 atm, and is hotter, when cools to “room temperature” the 2 atm gas will have more density and less velocity.
“Energy content” to me suggests density and/or higher velocity of gas molecules- *either one or both” are higher temperature.

88. Willis says:

You have not allowed for the fact that the atmosphere in the cylinder is mostly at the bottom. As a result, you have to move much more air up than down when you flip it. So it does involve a large input of work, despite the fact that its height did not change.

But I get all that work back when it passes the tipping point and the air rushes back to the bottom, just like flipping over a half-full bottle. The kinetic and potential energy in the final state is the same as in the initial state (except, in the case of a gas, for that thermally induced change in the center of mass I mentioned above), so there is no net input of work. You could drive the bottle flip with a spring and make a cute perpetual motion machine whose only flaw would be internal friction.

89. TimC says:

David says “To resolve this requires the question to be formulated as simply as possible. So to understand how gravity affects temperature distribution we [should] ignore – for the time being – anything extraneous. No sun, no rotation of the Earth, no surface or sub-surface effects. Simply a column of gas in a gravity field. Nothing more.”
But this then considers only the local effect of gravity on the planet itself – not the effect of the gravitational fields of other bodies. The second law (and gravity) applies universally – you must take into account that no known planet simply wanders about the universe as an orphan; all known planets (and moons) are under the control of some greater external gravitational force (unless perhaps caught in a supernova explosion – but that would be a special case!). This implies rotation (Keplerian orbits, axial rotation by conservation of momentum or gravitational/ tidal coupling), therefore nights and days, atmospheric mixing, heating, and radiation by the atmosphere itself.
Part of the problem with Jelbring is the assumptions applying to the model planet. Interestingly the same applied to Willis’s orphan planet with the non-GHG atmosphere (in his original Some Gravity “trap” thread) – perhaps in the hypothetical world we will find some form of paradox applying until it is accepted that all known planets rotate.

90. bones says:

The actual atmosphere temperature distribution cannot be modeled in terms of random molecular motions alone. The atmosphere is heated at the base by the absorption of UV and visible light. It warms to the point of hydrodynamic instability in the day and there is bulk flow energy transport from the warm base to higher elevations. Even without water vapor, CO2, methane or other greenhouse gases, ozone would absorb some of the outgoing IR. Without attributing either validity or falsity to any of the theories of atmosphere heat transport in discussion here, this is a complicated problem that is not going to be settled by simple arguments. Do the diurnal fluid mechanics problem along with atmospheric circulation and pole-equator insolation differences and then try to explain it in simple terms if you can.

91. dp says:

Willis – at some point I got lost and it was at the molecular replacement part. A highly energized molecule takes up more space than a lesser energized molecule. For there to be a one-to-one replacement of a displaced (convected) molecule, the molecule replacing it has to consume the same volume. Meaning it has to be at the same energy level. What compels molecules at the same energy level to swap chairs? Describe what happens to a lesser energized molecule when it drops into the hole left by a more energized molecule. And I know you know.
Then we will need to talk about gradients where all gradient elements are very close to every other gradient element. This gets to a very earthly feature known as long runout earth slides such as that which buried Pompeii. But first things first. Please give me the elevator speech description of why molecules of identical energy levels would swap chairs. I will snip your posts if you go off topic.

92. johnpb says:

Willis, It is hard to argue with your thought experiment due to your requirement of equalibrium which excludes convection. Once convection is allowed then adiabatic temperature differences will result.

93. James of the West says:

Temperature vs Energy of a gas.
What is the temperature of a gas? It is proportional to the *average* kinetic energy of the gas molelules whose temperature you are trying to measure but then we must always define which molecules are and are not included for the temperature measurement. We can do this by defining a region in space – a volume with x,y and z dimensions. The gas molecules in our region of interest don’t all have to have the same kinetic energy – as long as the average kinetic energy of the molecules in a given region of gas is the same it has the same temperature.
The total Energy (kinetic plus potential energy) can be very different in a cubic meter of gas at sea level to the same volume of a gas at the same temperature at altitude. The density (and mass) of gas in a given unit of volume also changes with altitude. It is simplistic to think of one molecule of gas as it turns potential energy into kinetic as it falls, when you consider a given volume of gas as it falls the number of gas molecules per unit volume increases this means that the potential energy of 1 unit of volume of a gas does not decrease simply as a function of altitude but also of density (mass per unit voume).
At altitude the number of gas molecules per unit volume is less than at the planets surface so that means the total kinetic energy (sum of the kinetic energy for each gas molecule) is declining with altitude even if the gases have the same temperature (average kinetic energy of the molecules). Again the Potential energy of the unit of volume of gas at altitude is higher per molecule but there are less molecules per unit volume so the sum total of the potential energy for a unit of volume of the atmosphere is also a function not only of gravity but also of the number of molecules in a unit of volume.
My hat goes off to those who delve into this further! Good luck to all of the smart people thinking about these matters.

94. Willis Eschenbach says:

richard verney says:
January 19, 2012 at 8:37 pm

… Why are we seeking to exploit solar energy by way of PV cells when this has obvious drawbacks such as sunlight is not received at night or when cloudy. Trenberth suggests that on average solar power is just 184 w per sq m. Why are we not exploiting backradiation or at any rate researching its use when it is claimed to be in the order of 333 w per sq m come rain or shine 24/7? If this was truly a souce of energy capable of doing sensible work, we would be exploiting it since it would cure over night the world’s energy needs. Something is amiss here and it is probably that physists employed by energy companies or at the cutting edge of research do not consider it a source of sensible work.

Richard, I’m sorry you think I’ve avoided the question. I receive dozens and dozens of questions daily and I cannot answer them all.
Several things. First, it’s not clear but it sounds like you think that downwelling longwave radiation (DLR) does not exist. I assure you that scientists routinely measure it daily around the world.
Second, photons of ultraviolet light have plenty of energy to stimulate band-gap jumps, creating the photoelectric effect. Blue light somewhat less. Green light and yellow light, only slightly. Red light, almost none. Thermal infrared, AKA “longwave”? Sorry. See here for a discussion. We can’t use it photoelectrically with our current technology, it doesn’t have enough energy to knock things loose. That means we’d have to use it as heat.
Here’s the problem with that. Bear in mind that do work with that heat, you need more than the heat. You also need to have a colder region to which you can reject the waste heat from the heat engine. In other words, you need a hot end and a cold end for a heat engine. It runs off of the temperature differential, not the temperature.
Finally, consider that wherever that IR is radiating from on high, it is coming from someplace colder than the surface. The global average upwelling radiation is on the order of 390 W/m2, or about 14°C. Downwelling global average radiation, on the other hand, is only on the order of about 320 W/m2, a few degrees above freezing.
So you can build your heat engine to use the downwelling radiation, but because everything around you is warmer than that radiation … where are you going to reject the heat? So you can’t use it to drive a heat engine.
Curiously, in certain circumstances you can pull your trick off, but only in in the backwards direction. By that I mean in areas where there are very few GHGs, you can utilize the lack of downwelling radiation. This was done in the old days in the southwestern US. The desert air is bone dry so GHG radiation is low. The folks there would put out shallow flat trays of water on the roof. This allowed the trays of water to reject their heat to the infinite coldness of space with little back radiation.
And as a result, the trays of water will freeze even though the ground temperature and the local air temperature never go below freezing at any point during the night.
At dawn, the people would take the trays of ice indoors before the sun came up, and put them in their ice storage, typically a hole in the ground filled with sawdust or other insulating material.
So in theory: You make ice during the night, then during the day you use the both solar and IR to heat the hot end of your heat engine and you use the ice to cool the cool end. But I digress.
That’s why we can’t pull work out of the downwelling longwave. Not enough energy for photoelectric, no cool place for rejecting heat.
All the best,
w.
PS—it strikes me that a satellite based heat engine (think thermocouple) could extract work from the upwelling planetary longwave, because it could reject the heat to outer space …

95. jorgekafkazar says:

Willis-san: Here’s your logic, above, with the symbolic logic thereof:
“If an energetically isolated system is in its lowest energy state, it cannot perform work”
If EIS = LES THEN -W
“If the isolated atmosphere in Jelbring’s thought experiment is warm at the bottom and cold at the top, I can stick a thermocouple into it and use the temperature differential to generate electricity to perform work.”
If EIS = HBCT THEN W
“Therefore, the isothermal state…is the lower of the two energy states, since I cannot use it to do work.”
-W THEREFORE EIS = LES
Do you see what you’ve done, Willis?
If Roger is a goose, I can’t ride him like a bicycle.
If Roger is a Schwinn, I can ride him like a bicycle.
I can’t ride Roger like a bicycle, therefore he is a goose.

96. We seem to be in the same boat Willis.
* We both thought that the lapse rate might be the equilibrium condition in this thought experiment.
* We both discussed it with other smart, informed people and decided the equilibrium condition is isothermal.
* We both realized a perpetual motion machine was the simplest argument against the permanent lapse rate situation.
That is how science should be done. I hate to admit I was wrong about physics, but there is no other conclusion possible here about the answer to this question. In our defense, there are arguments that sound very convincing that the temperature should drop as it go up. You REALLY have to know thermodynamics to avoid getting sucked in by those alluring arguments.
PS. The thought experiment is a very specific situation, not likely to be seen in the real world. Thermal conduction through the atmosphere is less than 1 mW/m^2 if the lapse rate is the maximum stable amount of 10 K/km. This number is SO much smaller that other energies involved (convection, incoming solar, GHG radiation, evaporation) that such an isothermal condition would never be realized in real life.

97. For those of you that believe empiricism trumps thought experiment, consider the following, attributed to Galileo, though it was also recorded ~1,000 years before Galileo by John Philoponus and also Oresme (IIRC) more than a century before.
Galileo asked us to consider what would happen if two iron balls were tied together as one by an iron rod. The smaller and lighter ball, according to Aristotelian physics, would slow down the ascent of the larger, heavier ball. Yet the combined weight, being greater than either ball alone, meant that they would fall faster when tied together, as well as slower. Since a contradiction was (and remains) not allowed, the answer to the problem was that objects necessarily fall at the same rate, regardless of their weight. Galileo had successfully demonstrated that Aristotle had been wrong about falling weights.
While Galileo is widely (and incorrectly) believed to have performed the experiment of dropping two cannonballs of differing weight from the tower at Pisa, this cannot be the case. In his record of the experiment, Galileo refers to the height from which a wooden and iron cannonball were dropped: 300 feet. This would make his assistant the tallest man in the world — ever!
In the event, Galileo recorded that the wooden cannonball initially fell faster than the iron cannonball, and that the iron cannonball overtook the wooden cannonball, beating it to the ground by a measurable margin.
Think about what we are doing when we attempt to reconcile the empirical result withe the deductive result.

98. Willis Eschenbach says:

dp says:
January 19, 2012 at 9:58 pm

Willis – at some point I got lost and it was at the molecular replacement part. A highly energized molecule takes up more space than a lesser energized molecule. For there to be a one-to-one replacement of a displaced (convected) molecule, the molecule replacing it has to consume the same volume. Meaning it has to be at the same energy level. What compels molecules at the same energy level to swap chairs? Describe what happens to a lesser energized molecule when it drops into the hole left by a more energized molecule. And I know you know.

dp, you should ask the author, Dr. Robert Brown, that question, as the description is his. I have only quoted part of it here. There is a link to his thread in the head post.
w.

99. Thomas L says:

Willis:
The problem is that the atmosphere Jelbring described cannot exist, and thus no meaningful statements can be made about it.
Suppose we have an atmosphere with a near surface temperature of 288K, and translucent in infrared frequencies. Then it must radiate to space at about the black body rate. Thus it will cool to the temperature of space, about 3K. In order to keep the atmosphere at a temperature above 3K, energy must be added. Indeed, to keep the atmosphere at 3K, energy must be added, via the cosmic background radiation. Once energy is added, whether at the top or the bottom of the atmosphere, the conditions for an isothermal atmosphere no longer apply.
It’s like dividing by zero. Once we let that slip in, whether by Jelbring or Eschenbach or Mann & Jones, we can get to any conclusion we want by following one chain of logic while ignoring another.

100. okay Willis, I take your point re gravity not affecting temperature. however I would argue that gravity is associated with temperature – I assume that temperature is highest in the core of astronomical bodies, as written.
yes temperature dissipates by convection and radiation.
but what is kinetic energy other than mainly a gravitational effect, a pull or a push ?
whilst this topic is ‘restricted’ to movements of air and temperature in a tube, and the subject of a planetary body minus an atmosphere, the real life said body of air operates in relation to a wider context – wind, height, temperature of surrounding air.
equilibrium is a temporary phenomenae. perhaps slowest rate of change is a near definition.
I have to go out. I’ll return to this later.

101. gbaikie says:

“It’s an interesting argument. Here’s my elevator speech version.
• Suppose we have an isolated container of air which is warmer at the bottom and cooler at the top. Any random movement of air from above to below a horizontal slice through the container must be matched by an equal amount going the other way.
• On average, that exchange equalizes temperature, moving slightly warmer air up and slightly cooler air down.
• Eventually this gradual exchange must lead to an isothermal condition.
I encourage people to read the rest of his comment.
Now, I see where I went wrong. Following the logic of my question to Dr. Brown, I incorrectly thought the final equilibrium arrangement would be where the average energy per molecule was evenly spread out from top to bottom, with the molecules having the same average total energy everywhere. This leads to warmer temperature at the bottom and colder temperature at elevation. Instead, at thermal equilibrium, the average energy per volume is the same from top to bottom, with every cubic metre having the same total energy. To do that, the gas needs to be isothermal, with the same temperature in every part.”
[-Sounds wrong.-]
“Yesterday, I read the Jelbring hypothesis again. As I was reading it, I wondered by what logic Jelbring had come to the conclusion that the atmosphere would not be isothermal. I noticed the following sentence in Section 2.2 C (emphasis mine):
The energy content in the model atmosphere is fixed and constant since no energy can enter or leave the closed space. Nature will redistribute the contained atmospheric energy (using both convective and radiative processes) until each molecule, in an average sense, will have the same total energy. In this situation the atmosphere has reached energetic equilibrium.”
So, it’s the “average molecule” which has same energy [velocity] and in less density the amount energy per cubic meter is less [and is therefore is colder- doesn’t warm as much something like thermometer].
But no molecule stays at same velocity. Or make it simple, maybe, molecules don’t go [normally] in any vector for more nanosecond.
In convection one can have a group “averaged molecules” going in one direction or vector or have something one calls velocity- but none of these actual molecules is actually going in one direction- it’s more like sound wave. it’s possible for a gas molecule travel say a meter or more in one direction, but chances are low of this happening. With zillion and zillion them, one probably goes mile fairly commonly:)
Example of the theory as I understand it.
Have two flat areas of real estate. Have them at different elevation. On at sea level and one at 10 km in elevation. And they are on same planet. They will have different density of air 1 meter above their surfaces.
On the land at 10 km in elevation should receive more sunlight. But let’s say the both receive same amount of sunlight. These areas of real estate are hundreds of square km and flat.
The one at higher elevation will not warm the air to as high a temperature as the land at sea level. The higher elevation land will increase the gas molecules speed to same velocity as the sea level land, but there is low density, so it’s cooler.
And even with more sunlight in higher elevation it would make the gas molecules travel faster, but it still would be cooler air temperature.
If this is true, than lower elevation has a “greenhouse effect”.
And the land at higher elevation should have it’s dirt at higher temperature [if has more sunlight]- and less greenhouse effect in this sense.

102. Willis Eschenbach says:

jorgekafkazar says:
January 19, 2012 at 10:14 pm

Willis-san: Here’s your logic, above, with the symbolic logic thereof:
“If an energetically isolated system is in its lowest energy state, it cannot perform work”
If EIS = LES THEN -W
“If the isolated atmosphere in Jelbring’s thought experiment is warm at the bottom and cold at the top, I can stick a thermocouple into it and use the temperature differential to generate electricity to perform work.”
If EIS = HBCT THEN W
“Therefore, the isothermal state…is the lower of the two energy states, since I cannot use it to do work.”
-W THEREFORE EIS = LES
Do you see what you’ve done, Willis?

Not a clue, my friend. Your pseudo-algebra is meaningless. Try putting units on it to see what I mean. Unless you think that is symbolic logic, but it’s not any kind that I recognize.

If Roger is a goose, I can’t ride him like a bicycle.
If Roger is a Schwinn, I can ride him like a bicycle.
I can’t ride Roger like a bicycle, therefore he is a goose.

jorge, i seriously have no clue what you are on about. It seems you think I’ve made a logical mistake. Let me recap the logic.
I stick a thermocouple in an isothermal atmosphere. I cannot extract any work.
I stick a thermocouple in an atmosphere that is cold at the top and warm at the bottom. I can extract work.
Which one is the lower energy state?
w.

103. Poriwoggu says:

Gravitational heating comes from contraction of a gas. Potential energy is converted to kinetic energy.
The sun when it originally formed would have had enough kinetic energy to shine for about 18,000,000 years. However – after about 18,000,000 years it would be cold and dead without nuclear fusion.
The atmosphere of earth may have contracted at some point but that energy dissipated several billion years ago.
The gravito-thermallers are kind of right – it may have happened, once. But that train has left the station and doesn’t impact current atmospheric conditions. The potential energy was converted and radiated away a long time ago.

104. Mike Wryley says:

Willis,
I am beginning to think that there may be another effect at work to raise the temp due to gravity, but not for the reasons suggested. Because of the small angle subtended by the earth vis a vis the sun, the energy comes in a collimated beam. Essentially, most of the photons, whatever their energy, have a pretty good shot at the surface of the earth. However, once the surface or the gas
near (first couple miles let’s say) the surface reradiate this energy, it goes off it all directions. Due to density differences in the atmosphere caused by gravity, I would expect some of this energy to be reflected back at lower angles of incidence to the horizon due to refractive effects in the atmosphere, similar to the mirror like effect seen on a hot highway at low look angles. The compressed gas of the atmosphere creates a diode effect for inbound radiant energy. No clouds required.

105. Willis Eschenbach says:

Thomas L says:
January 19, 2012 at 10:22 pm

Willis:
The problem is that the atmosphere Jelbring described cannot exist, and thus no meaningful statements can be made about it.

First, this is a thought experiment. Einstein famously explained relativity using the thought experiment of an elevator in space. Of course, something like that cannot exist … but it can still be very useful in understanding the real world.
Second. suppose we find a planet with an atmosphere with no nearby sun. We put a foam shell around it, so it is almost entirely energetically isolated from the universe.
That is the atmosphere Jelbring describes … so why can’t that atmosphere exist?
w.

106. Thomas L says:

George Turner says:
January 19, 2012 at 7:34 pm
Nice try. Before you rotate the cylinder, the air at the top of the cylinder has lower pressure than the air at the bottom of the cylinder, and therefore the density at the top is less than the density at the bottom. So when you turn the cylinder over, you are doing work, as moving the bottom up takes more energy in a gravity field than you get from moving the top down. And the air in what was the top (now the bottom) gets compressed and heated, while the air in what was the bottom (now the top) expands and cools. But you knew this.

107. Theo Goodwin says:

Bryan says:
January 19, 2012 at 4:30 pm
Perhaps Willis will suggest a real experiment with real materials to test the alternative conjectures.
Say with a thermoelectric device to make use of the temperature difference.
A computer simulation program would not be any kind of proof
I think he will find with real materials that this is beyond him
Perhaps this is why there has never been an experiment to settle the matter!
Yes, the distance from textbook to rigorously formulated physical hypotheses is huge. In fact, it is so large that it contains all the science, except for checking the predictions. To the Warmists it is a vast desert that they dare not enter.

108. JeffT says: Jan 19, 5:00 pm If there is a temperature gradient between two parts of a system, net heat flows from the warmer part to the cooler part.
/headslap! Thank you, Jeff, it is that simple. Total energy, chemical Potential energy, mechanical potential energy do nothing to prevent temperature equilibrium.
Take a pressure cylinder. Fill it with iron springs and Freon. Put in the piston. Place it is a bath or air, water, or any other fluid. Press the piston to its max. The contents of the cylinder heats, the iron springs compress, the Freon compresses then liquefies releasing more heat. Wait a bit. The Cylinder system contains a lot of potential energy, but it and its bath will come to the same temperature in time.
Release the piston and the temperature of the cylinder will drop and then be warmed by the bath back to a lower temperature. This example does not employ gravitational potential energy, but I’m convinced. Total energy is irrelevant.
So on a uniformly heated, dead planet at equilibrium, the atmosphere will have a zero lapse rate, isothermal atmosphere. But bring on a day and night cycle, then differential heating will force a lapse rate to become established by adiabatic processes regardless of the atmospheric composition. All we need to know is the specific heat of the atmosphere and the surface gravity: Cp/g. http://wiki.answers.com/Q/What_is_the_dry_adiabatic_lapse_rate_on_Venus.

109. anna v says:

Could one do the experiment using water as the fluid?
A long insulated tube (thermos like?) with temperature sensors along and a small tube inside for air to get out. Pour water at fixed temperature. Measure along tube. It would not have to be very long with good temperature sensors, a tower would do.

110. Downdraft says:

1. The elevator soliloquy:
The mass of the atmosphere, solar insolation, and the temperature of the upper atmosphere determine the temperature at the surface of a planet of sufficiently thick atmosphere. The exact makeup of the gasses of the atmosphere is not important, as it can be assumed that essentially all outgoing long wave radiation is absorbed and re-radiated in the lower atmosphere, finally being radiated to space from the upper atmosphere. Surface temperature is simply a function of the temperature of the effective black body temperature of the upper atmosphere required to radiate heat equal to the net insolation of the total planet, the mass of the atmosphere, and the gravity of the planet.
Climate change and excursions from average can be attributed mainly to changes in the mass of the atmosphere, albedo, and insolation, and are largely independent of minor changes in LW absorption in the atmosphere.
2. I must disagree with Dr. Brown. In a tall column of gas acted on by gravity, and at equilibrium, in a perfectly insulated container, the top of the column will be colder than the bottom of the column. All gas will be at an equal energy state (by mass, not volume), and since gas at the top has more potential energy, it must be at a lower thermal energy state in order to have the same entropy value. In other words, the adiabatic lapse rate still applies. This is essentially the situation that occurs in the atmosphere, on a very large scale.

111. Stephen Rasey says: 4:54 pm: Assuming that Index of refraction (Ir(r=ground) is higher near the ground than at high altitude Ir(r=large), then there is a focusing of energy.
Nope! Effects cancel out. Index of refraction might make it possible for someone on the surface of a planet to see more than 180 degrees of the outer shell. But each point on the outer shell is illuminating an equally larger area of the planet, thus diluting its contribution at any one point. Therefore, there is no net focusing, no net increase in energy, and an isothermal atmosphere even with index of refraction that increases with pressure.

112. Thomas L says:

Willis Eschenbach says:
January 19, 2012 at 10:32 pm
You have a planet not near a star and heat the atmosphere to 288K. You construct an insulating sphere to hold the heat in. If the atmosphere is isothermal, the TOA is at 288K. This will heat the insulation to 288K. The insulation will then radiate to space at 288K. Of course the radiation rate could be very slow, but we are talking about equilibrium here. If we make the foam slightly radioactive, then we get near equilibrium, but only until enough half-lives have passed.
If there is a material that is 100% reflective at microwave through visible frequencies, that would keep the atmosphere either isothermal or iso-energetic. Iso-energetic implies a lapse rate related to the gravity gradient. My memory of thermodynamics is not enough to tell me which way the energy gets partitioned, but I think it’s iso-energetic.
Or we could surround the planet with insulation in the form of turtles. Then it’s turtles, all the way up.

113. jorgekafkazar says:

Thus spake Willis (re thermonuclear heating): “I ran the numbers in the past. I don’t have them in front of me, but it is very small, less than a tenth of a watt per square metre from memory. There are a variety of geothermal regions, and hot vents under the sea, and hot springs and pools on land. But you have to consider—for every hot springs you know of, there are thousands of square miles of land with no hot springs, where if you go to sleep in the morning, you wake up very cold. So yes, you are right, there is a heat source down under. But it is very small, even if we have greatly underestimated it.
Right, Willis. I did the calculation a couple of years ago, and the conducted core heat is minuscule. If we look at mass transfer of hot material (hot springs, volcanoes, etc.), the numbers may be more significant. It is estimated that there are on the order of three million undersea volcanic vents. Most of these are small, but we don’t really have a handle on their total heat load, nor do we know exactly where it goes or how fast. (These seeps also emit CO2, but that’s another story,)

114. Bart says:

“Dr. Brown said no. He said that at equilibrium, a tall container of air in a gravity field would be the same temperature everywhere—in other words, isothermal.”

There is no equilibrium of a column of air in the gravitational field of a spherical planet unless there is a heat sink drawing energy away from the atmosphere. The heat equation does not allow a spherically distributed atmosphere to attain thermal equilibrium.
Without radiating gasses to draw the heat energy away, the atmosphere of a planet is like an ideal electrical capacitor hooked up to a constant voltage source, or an ideal inductor hooked up to a constant voltage source. It has nowhere to dissipate the energy, so the energy just keeps accumulating.
Eventually, the capacitor pops, or the inductor melts. In the real world, stray conductance or resistance, respectively, if they are large enough, prevent destruction. In the same way, a planet with insufficient radiation boils away its atmosphere, or achieves an equilibrium when sufficient radiation takes place from unaccounted emitting particles.
I have fleshed this all out in the previous thread starting about here.
So-called greenhouse gasses do not heat the surface – they prevent it from overheating. They are like a resistance put in parallel with that capacitor, or in series with the inductor.
In steady state, there is no difference between my description and the standard greenhouse hypothesis. On Earth, IR emitting gasses arrest the runaway heat accumulation that would otherwise exist. Backradiation equilibrates with the net overage in steady state Stefan-Boltzmann emissions from the planet’s surface.
So, there is no discriminator in the steady state, which is why people have been led astray for so long. They have been using Stefan-Boltzmann in ways it was not intended to be used – Stefan-Boltzmann only holds in conditions of equilibrium or, at least, quasi-equilibrium. The atmosphere of a planet without significant emissions is never in equilibrium, or even quasi-equilibrium.
The solution of the heat equation in spherical coordinates tips the balance in determining the real process going on. Without atmospheric emissions, there is always a temperature gradient leading into the atmosphere, and the atmosphere therefore continually accumulates energy. There is no adiabatic lapse rate possible without a heat sink in the atmosphere above. But, there is a lapse rate.
Look at the earlier thread. I’ve got it nailed. There is no doubt about it.

115. Bart says:

Erratum:
Without radiating gasses to draw the heat energy away, the atmosphere of a planet is like an ideal electrical capacitor hooked up to a constant current source…

116. “On average, that exchange equalizes temperature, moving slightly warmer air up and slightly cooler air down.”
Willis, I’m not sure whether that summarizes what Dr Brown said, but it’s wrong, and for a fundamental reason.
When the lapse rate is below the dry adiabat (toward isothermal) it is referred to as convectively stable. Above the adiabat, it is unstable. At the adiabat, it is neutrally stable.
At the adiabat, rising air cools by expansion, at exactly the rate at which the nearby air is becoming cooler (by lapse rate). And falling air warms. There is no buoyancy issue created. Moving air retains the same density as the environment. And no heat is transferred.
But in the stable regime, falling air warms faster than the change in ambient. It becomes less dense, so there is a force opposing its rise. That is why the air is stable. This motion both takes kinetic energy from the air and moves heat downwards (contra your statement). It is a heat pump which works to maintain the lapse rate.
Rising air does the same. It cools faster, and so rises against a buoyancy force. It takes KE from the air and moves “coolness upwards”, ie heat down. It pumps heat just as falling air does.
That is why air in motion tends to the adiabat lapse rate. A heat pump requires energy. Where from?
The atmosphere is famously a heat engine, driven by temperature differences, most notably from equator to pole, but also innumerable local differences, eg land/sea. This provides the kinetic energy that maintains the lapse rate, and it is hard to imagine any planetary atmosphere where the energy would not be available.
The effectiveness of the heat pump tapers as the adiabat lapse rate is approached. Beyond, in the unstable region, everything is reversed. The pump becomes an engine, with heat moving upward creating KE. This of course quickly diminishes the temperature gradient.
It’s true that with no motion at all, conduction will render the air isothermal.

117. “a force opposing its rise”
I meant, opposing its fall.

118. Bart says:

A few posts from the other thread to help the discussion:
Solution of the Heat Equation in Spherical Coordinates
Bart says:
January 18, 2012 at 12:11 pm
In an atmosphere with no convection (the thought experiment world), the PDE governing the temperature is
dT/dt = alpha*del^2(T)
where alpha is the conductivity parameter and “d” is actually a partial differential operator and del^2 is the Laplacian. To solve this equation, we set T = T1(t)*T2(r), where T1 is wholly a function of t, and T2 is wholly a function of r. This leads to
(dT1/dt)/T1 = alpha*del^2(T2)/T2
where the “d’s” are now total differential operators. Since the left side is wholly a function of time, and the right wholly a function of r, they must both equal a constant, call it lambda.
Then, the solution of dT1/dt = lambda*T1 is elementary, T1 = T1(0)*exp(lambda*t). The solution of
del^2(T2) = (lambda/alpha)*T2
is a modified and adjusted zeroth order Bessel function of the second kind, which is qualitatively similar to a constant divided by radius.
Thus… the full solution is
T = T(0,0)*exp(lambda*t)*F(r)
There is always a gradient downhill in the radial direction. Thus, there is always heat flow into the higher altitudes. This heat flow will continue until it stops, either by high energy radiation if the atmosphere allows, or boiling away of the atmosphere.
Solution is a little more complicated than that, but same general morphology
Bart says:
January 18, 2012 at 1:56 pm
The alpha parameter is actually called “thermal diffusivity”, and it is inversely proportional to density. So, as the altitude increases, alpha will grow larger. So, even the Bessel function solution is not precise, and will only hold approximately in the lower atmosphere and before significant thermal expansion has taken place. A precise global solution would have to take all of these factors into account.
But, there is no chance of steady state because the steady state solution is T = B/r for a constant B, and since there is a gradient, there cannot be a steady state, and that creates a contradiction. So, the conclusion remains: there is always a thermal gradient pushing heat continuously into the atmosphere, and it will not stop until either there is some kind of radiative release, or the atmosphere flees.
Why the solution cannot be a constant, part I
Bart says:
January 19, 2012 at 1:52 pm
…Starting from some temperature at the base, in any finite time, the temperature is going to be less out farther than it is nearer, and it is going to go to zero at infinity. So, there must be a gradient over any finite time.
What is the form of that gradient? Well, through separation of variables, the temperature function is the product of a time varying part, and a spatial varying part. The spatial varying part is a function of spatial coordinates only, so it does not change with time. Therefore, since for any finite time, the spatial solution is of the form A + f(r), where A is a constant and f(r) is a monotonically decreasing function of r, and A must be zero at that time, then it must always be zero, and f(r) must go to zero as r approaches infinity.
QED.
Why the solution cannot be a constant, part II
Bart says:
January 19, 2012 at 8:14 pm
…So, if the “mode shape” of this thing is a constant independent of radius, that means the entire spherical shell has to heat uniformly. It starts at zero everywhere. It is at 1K everywhere at the same time. It is at 100K everywhere at the same time. This is physically impossible based solely on the fact that the rate of heat conductance is finite.

119. F. Ross says:

Willis,
If I understand what you are asking in this post, here is my elevator speech. If I have misunderstod, my apologies.
Imagine a 10km perfectlyl insulated column of gas.
Outside the tube connect one end of a suitably sensitive, perfectly insulated thermocouple to the top and bottom of the tube.
1. If a continual current flow is detected from the thermocouple, then the temperatures at the top and bottom of the column are different and one has a perpetual motion machine. *
* Series-parallel enough of these structures and our energy problems are solved – until gravity runs out, anyway.
2. If, after a suitable period of time no current flow is detected then the top and bottom of the column are at the same temperature.
I’m betting on #2.

120. Kasuha says:

I disagree with idea that the temperature on each layer is the same or that the energy per volume is the same, both are IMO wrong.
Let’s imagine an ideal gas container in gravitational field. In our gas particles don’t interact at all. As long as the gas is in equilibrium, each of its particles has the same total energy at every moment (but the important point is that total energy is sum of kinetic and potential energy). These particles travel on parabollic trajectory, bouncing off the bottom. This gives us overview of the energy distribution over the container volume – at the very top, the speed of particles is zero and the temperature is zero as well. At the very bottom the particle temperature is proportional to square of the height of the trajectory. The equilibrium condition is held too because on each horizontal layer boundary you get exactly the same number of particles traveling up and down at exactly the same speed.
This model I believe gives us very good idea about temperature, pressure and energy distribution over the container even for normal gases with interacting particles.
Another important thing is, your thermal perpetuum mobile cannot work in this temperature gradient as the medium you use in it follows the same rules the gas does. To raise your medium to the height where you intend to let it cool down you use more energy than you gain by letting it cool down there.
_______________
Now, I may be completely wrong somewhere in the above (transition from ideal non-interacting gas to normal interacting one feels to be the weakest point) so my main points are:
– potential energy is completely omitted in the article arguments
– the argument with thermal perpetuum mobile is invalid because the medium must follow the same rules the atmosphere does. If gravity created temperature gradient, it cannot be used by thermal engine.

121. Legatus says:

One needs to ask, why is our air at different temperatures on earth at different altitudes? For one thing, we do not have an impervious membrane around us, and we have this thing called the sun shining at us. Result, the ground and especially water is heated or energized, and conducts heat to the lower air by direct contact, evaporation, etc. Result, the air at the bottom is warmer than air higher up. However, if you go very high, you reach ozone, which can and does absorb UV radiation, making it hot (and heating the non ozone around it) and causing it to expand way out into space. This will have some effect heating from the top down, although since this air is very thin the total amount of energy it can add to air lower down isn’t much. There is also some heating caused by the various GHG’s (especially water vapor) being heated by radiation and heating the air around them. Conclusion, there are reasons why our air is at different temperatures at different altitudes and it has nothing to do with any gravito thermal effect.
Second, if earth were as described, with an energy impervious barrier around it (and it had no fissionables), it would be at absolute zero. Even if gravito thermal worked, any air that contacted the earth would contact a very cold surface. The much more dense earth would quickly absorb all the heat from the air, which would freeze out rapidly, goodby gravito thermal effect.
However, let us assume, for arguments sake, that the surface of the earth and the air start out at the same temperatures as our surface and air. If gravito thermal works, and the people make huge heat engines, they will have to produce a lot of energy to make up for the fact that the cold ground will absorb and keep on absorbing the energy. They could, I suppose, surround the entire earth with an insulating material to slow this heat loss. If they did, they could be comfortable assuming the heat engines can create enough heat and light for them and to make up for the slight loss to ground. An impervious insulator below them would result in the energy and heat from their engine building up rapidly in the space between the insulator above and below them, which would continue until it melted the engines and stopped their operation. A not quite perfect insulator below them could keep them comfortable until the ground below the insulator had warmed up all the way through, at which point the people would find it slowly getting warmer, continuing until once again it gets warm enough that the heat engines melt and no more heat is, apparently, being produced from nothing.
Third, let us assume that the earth, as ours does, has fissionables in it’s core, and that is why the surface is warm. However, since there is a barrier to energy above them, this heat will slowly build up, since it cannot escape, until all the fissionables are used up. If it has a lot of them, as our earth seems to, it will get very hot before that happens, and once all the fissionables are gone, it will stay at that hot uniform temperature forever. However, lets us say, for arguments sake, that the last fissionables are used up just as it reaches a nice comfortable temperature (one where air does not freeze out). Now let us say that the people there, somehow, in the dark, invent heat engines to take advantage of this gravito thermal effect to make light and power. This will slowly add heat to the earth (the solid planet will absorb most of it) and very slowly heat things up. Eventually, it will get too hot, all the people will die, the engines will stop, and it will stay at this new, somehow elevated temperature forever. If you could somehow create indestructible heat engines that never melted and didn’t need tending, the heat would slowly build up forever, eventually the inside of the membrane would be hotter than any sun (which, I suppose, since it melted the earth, would stop the gravito thermal effect). As we can see, even under ideal starting conditions, if we assume that this membrane surrounds the earth, and we assume ideal starting temperatures for gravito thermal to work, it always results in energy being created from nothing, and the space inside the membrane getting hotter and hotter.
I think all this shows that under any circumstance we start with, even absolutely ideal (and impossible) starting conditions, gravito thermal results in an impossible outcome, with energy inside the membrane building up from nowhere. It should also be noted that the whole thought experiment is ridiculous anyway, such and energy impervious barrier cannot exist in our universe with it’s laws anyway. Thus we see that the only way gravito thermal can work is in a universe that is entirely imaginary, and has different natural laws that ours does. In other words, the authors of this idea are living in a world all their own, literally. They would realize that if they thought through all the implications of all this, as I have above.

122. Willis Eschenbach says:

Bart says:
January 19, 2012 at 11:06 pm

“Dr. Brown said no. He said that at equilibrium, a tall container of air in a gravity field would be the same temperature everywhere—in other words, isothermal.”

There is no equilibrium of a column of air in the gravitational field of a spherical planet unless there is a heat sink drawing energy away from the atmosphere. The heat equation does not allow a spherically distributed atmosphere to attain thermal equilibrium.

So in the Jelbring thought experiment you are saying the atmosphere never, ever achieves thermal equilibrium? If not … why can’t we pull work out of it with a thermocouple?
Regards,
w.

123. Willis Eschenbach says:

Nick, first you say:
Nick Stokes says:
January 19, 2012 at 11:15 pm

“On average, that exchange equalizes temperature, moving slightly warmer air up and slightly cooler air down.”

Willis, I’m not sure whether that summarizes what Dr Brown said, but it’s wrong, and for a fundamental reason.

Then you say:

It’s true that with no motion at all, conduction will render the air isothermal.

Since Dr. Brown is talking about air in a tall container, we’re talking about still air. The same thing is true in the Jelbring thought experiment, air with no motion in both cases.
As a result, I don’t see why you say Dr. Brown is wrong.
w.

124. Willis Eschenbach says:

F. Ross says:
January 19, 2012 at 11:31 pm

Willis,
If I understand what you are asking in this post, here is my elevator speech. If I have misunderstod, my apologies.
Imagine a 10km perfectlyl insulated column of gas.
Outside the tube connect one end of a suitably sensitive, perfectly insulated thermocouple to the top and bottom of the tube.
1. If a continual current flow is detected from the thermocouple, then the temperatures at the top and bottom of the column are different and one has a perpetual motion machine. *
* Series-parallel enough of these structures and our energy problems are solved – until gravity runs out, anyway.
2. If, after a suitable period of time no current flow is detected then the top and bottom of the column are at the same temperature.
I’m betting on #2.

I’m betting the same way. I note that Bart wants to drag in a thousand and one complex equations. I say no matter what Bart claims about the equations, we can’t get an ongoing current from the tall columns. Period. Which means that they are isothermal.
w.

125. wayne Job says:

Let us forget gases for a moment and consider golf ball size particles made from lead, as our atmosphere, closely packed near the surface and twenty miles above loosely packed.
The potential energy of the balls at twenty miles up is huge. Consider these as cold molecules falling under gravity and impacting other molecules. Other molecules heated by conduction from the Earth by the sun are rising to meet them, and meet them they do head on. Thus slowing the transfer of Sol’s heat, graciously given to the world back into space. This is the major part of the misnamed green house effect. The rest of the green house nonsense can be explained by compression of the atmosphere close to the surface, where the molecules are elbowing for room.
The modulation to all this is water in it’s various phases, that gives us a livable planet, chaotic as it is.

126. joshua Corning says:

For such machines to work, they’d have to create energy, and energy cannot be either created or destroyed, only transformed.
So the earth can’t orbit around the sun because that would break the laws of thermodynamics?
I hate to break it to you Willis but you have gone off the deep end.
The reason that gasses in an atmosphere are of higher temperature then if they were floating around in a vacuum are the same reasons why the earth can continue to orbit the sun without constantly being pushed.
i will restate my thought experiment again.
Imagine gas floating around in a cloud in the vacuum of space. it is spread out and the interactions between the atoms in the cloud are sparse…now imagine that cloud being pulled down a gravity well of a planet. the gas gains no energy yet it is now under pressure….now the atoms are all close together and colliding and doing what atoms do when they are forced to be in close proximity to one another. Again the atoms energy has not changed. yet their temperature is higher.
see how that works?
And it can be proven. Take the temperature of any old room….now compress air from that room into a container…now measure the temperature of the compressed air in that container…..guess what the air inside the container is hotter then the air in the room.
now i know what you are going to say “you used energy to compress that air” you are correct i did…but when atoms are compressed by gravity as in an atmosphere then no energy is used to compress it.
anyway i just thought of how this can balance thermodynamics….think of school teacher holding a ball in the air then he drops it. the teacher then says the ball while he held it had potential energy and when he released it it had kinetic energy. Think of the gas floating around in space as potential energy and when they are pulled down a gravity well of a planet as kinetic energy….you see they had that potential energy from when the universe was created and now that they are compressed by the planet’s gravity they have kinetic energy.
I really cannot explain it simpler then this…..if you cannot grasp it i have to suspect it is from willful ignorance.

127. joshua Corning says:

“If left undisturbed in a gravity field, a tall container of air will stratify vertically, with the coolest air at the top and the warmest air at the bottom.”
Note that the atoms at the top have the highest energy and the lower ones the lowest.
The reason the temperatures are reversed is simply because at the top of the column you have less atoms hitting the side of your thermometer then you do at the bottom.
I think part of the problem is that although you understand that hot air moves to cold air i think you either are forgetting or don’t understand why atoms do that.

128. Willis replied to Ferds comment;
‘Temperatures have leveled. Sea levels have stabilized. CO2 has not. These events contradict GHG theory predictions, which in science is a strong indication the GHG theory is wrong.’
By remarking;
‘Thanks, ferd. I come to a very different conclusion from the same facts. I say that the greenhouse effect has done the heavy lifting of bringing us to our warm current temperature….’
Temperatures have been slightly higher than today and sea levels also higher on several ocassions during the last 5000 years. Self evidently that wasn’t due to raised co2 levels (according to the stated records)
What did the ‘heavy lifting on those occasions? Natural variability? if so couldn’t that be the cause again today?
tonyb

129. Willis Eschenbach says: January 19, 2012 at 11:52 pm
“I don’t see why you say Dr. Brown is wrong.”

In the quote that I cited, it explicitly says that motion of the air equalizes temperature. And it doesn’t, for the reasons that I gave.
But I was more concerned to say what it does do. It provides the heat pump which counters conduction and radiative transfer down the gradient.
And still air is impossible. You need a heat source to prevent liquefaction (from radiative loss), and that in practice will create temperature differences and motion, which in turn pushes toward the adiabatic lapse rate.

130. alex says:

What the guys makea big tohuwabohu out of a very simple problem?
What is all this poetic story about?
Willi, it’s trivial as a nutshell.
1. There is a big difference between a tall air “container” and an atmosphere: the atmosphere is MIXING (troposphere = mixing sphere), your “tall container” is not.
2. If there is mxing, the only equilibium is very simple: ds/dz=0, where s is the entropy density. You have the thermal source at the bottom – the Earth surface heated by the Sun, and the thermal sink at the top – radiation to the space by the GHGs or clouds. In between you automatically get ds/dz=0. This is the adiabate that gives you the temperature lapse.
3. In your non-mixing “tall container”, there is no energy sink at the top. Thus, the temperature is constant. T=const. Very simple.
4. The temperature at the Earth’s surface is NOT defined by the GHG concentration, if the GHGs screen the Earth’s IR radiation completely. In this case, you must calculate the energy balance AT THE RADIATING SURFACE that is special for every wavelength: it is the altitude, where the atmosphere becomes transparent for the radiation. In this way you obtain the temperature up there.
5. Now you start your adiabate from this radiation surface at the top of the troposphere (the energy sink) and go down to the planet surface. Here you use the adiabate with its temperature lapse rate. The higher the atmospheric pressure at the bottom, the higher the temperature. Has nothing to do with “perpetuum mobile”.
6. For the reason discused above, Venus is hot as a hell due to the high atmospheric pressure (NOT GHG “concentration”), Mars with its low atmospheric pressure (although 20x more CO2 than the Earth!) is freesing and we have the comfortable climate.
Alex.
5.

131. Thomas L said:

Nice try. Before you rotate the cylinder, the air at the top of the cylinder has lower pressure than the air at the bottom of the cylinder, and therefore the density at the top is less than the density at the bottom. So when you turn the cylinder over, you are doing work, as moving the bottom up takes more energy in a gravity field than you get from moving the top down.

But that’s also true if the air was already at the adiabatic lapse rate. In that case, when I flip the cylinder, the end state will be exactly the same as the initial state, so no net work was performed. I lift the air, I lower the air. I do work lifting, then have work done to me as I set it down. I do work tilting the cylinder 90 degrees, then have work done to me as I resist the further rotation as the dense air pours to the other end to try and complete the flip. It’s the same as pendular motion.
Back to Willis’s original thought experiment (and perhaps its key point) I’m not sure you can pull work out of the adiabatic atmosphere with a thermocouple, as I’m not sure anyone has dug that deeply into heat transfer in a solid in a gravitational field. For example, the thermocouple has to conduct the energy (as heat) along its length. If we pick the best standard material for heat conduction, silver, and work at the Earth’s adiabatic lapse rate of about 2 degrees C per thousand feet, we can only conduct about 2.4 Watts per square meter of silver conductor, even horizontally. Such low levels of heat transfer over such vertical distances might require the inclusion of effects that are irrelevant in most applications. putting us below the round-off error in the equations that work acceptably well in other applications. I’m pretty sure nobody has tried to use 2 degrees C to move only 2.4 watts upward through a silver or copper slab a thousand feet tall and a square meter in cross section, which is the same as using 160,000 tons of silver, the weight of almost four Iowa class battleships, to cool a 200 Watt CPU by just 2 degrees.
We could sidestep the question by positing that solid masses are allowed to reach thermal equilibrium at the top and bottom of the atmosphere, then are insulated and moved into contact with the thermocouple. I don’t know if this would raise questions about KE and PE of the solid bodies, though, or whether moving them that distance without losses would itself be a perpetual motion machine.

132. Willis Eschenbach says:

joshua Corning says:
January 20, 2012 at 12:08 am

For such machines to work, they’d have to create energy, and energy cannot be either created or destroyed, only transformed.
So the earth can’t orbit around the sun because that would break the laws of thermodynamics?
I hate to break it to you Willis but you have gone off the deep end.

The Jelbring thought experiment concerns a closed system, with no energy going either in or out. I don’t recall saying the earth could not orbit the sun, you’ll have to cite that. In any case, that’s an open system.
Thanks,
w.

133. Colonial says:

Joe Born (January 19, 2012 at 5:42 pm) wrote:
[If the] … Velasco et al. paper is correct, its Equation 8, a result of statistical mechanics, dictates that average kinetic energy decreases with height even at equilibrium.
I’m not an atmospheric scientist, just an electrical engineer who had a single thermodynamics class 40+ years ago, but the comment above matches my reservations. Let’s postulate a sealed container filled with a perfect gas (defined as an ideal gas which additionally is completely transparent to radiation), similar to that proposed by Willis. The container begins at ground level, where the pressure is 1,000 millibars, and extends to the altitude at which the pressure would be 500 millibars if the gas were isothermal. Let’s grab a small amount of gas at ground level and raise it (without disturbing any other molecules) to the top. When we do that, we add potential energy of position to the gas molecules that rode the elevator to the top.
Where did that energy come from? Unless there’s another source of energy that can be tapped (a violation of the assumed equilibrium conditions in our sealed container), the energy has to come from the kinetic energy of the molecules that were raised from bottom to top. If it comes from anywhere else, we’ve added extra energy to the molecules that were raised that can then be used to perform work, creating yet another perpetual motion machine!
If we take the sealed container postulated above and evacuate it until there’s only a single gas molecule left, it’s clearly true that the total energy of that lonely gas molecule is the sum of its potential energy of position and its kinetic energy. When the molecule is at ground level, it will have the highest possible kinetic energy (implying a higher temperature), and zero potential energy of position. If it travels straight upward until it reaches the top of the sealed container, it will have the highest possible potential energy of position for that system, and correspondingly lower kinetic energy (implying a lower temperature).
When the sealed container has the normal complement of perfect gas within it, the mean free path of any given gas molecule will be very short (Wikipedia says 68 nanometers for air at 1013 millibars). However, between collisions, the vertical component of each molecule’s velocity will be affected by gravity, just as in the case where only a single molecule is present. If the vertical component is upward, it will trade kinetic energy for energy of position, cooling slightly in the process. If the vertical component is downward, it will trade energy of position for kinetic energy, warming slightly in the process.
So, the heresy, spoken aloud: A perfect gas within a sealed container will exhibit a temperature gradient in a gravitational field. This is not, however, a substrate for a perpetual motion machine. The total energy (kinetic plus potential energy of position) of each molecule is the same. Any attempt to extract energy from the difference in temperature between the top and bottom will founder on the reality that entropy has already been maximized for the gas within the sealed container. There’s nothing left to get.
You’ll note that at the beginning, I specified that the sealed container had a pressure of 1,000 millibars at the bottom and 500 millibars at the top. It’s been too many years since I took physics to allow me to easily perform the calculations, but someone who performs such calculations regularly should be able to calculate the energy required to raise a molecule from the bottom to the top, subtract it from the assumed kinetic energy of a molecule at 1000 millibars, and determine the remaining kinetic energy for that molecule. This would allow calculation of the actual pressure at the top (nominally 500 millibars), and the temperature gradient that would exist in the sealed container because of gravity.

134. Neil says:

I have never seen so much ignorance in one blog
Does no one understand the dry adiabat for the atmosphere on Earth (DALR=9 degrees per Km)?
This is entirely controlled by gravity and by the mass of the atmosphere– nothing else.
(hence it varies for other planets)
It applys to the larger atmosphere in exactly the same way it it does in an insulated cylinder of dry air
Does no one here understand the TePhigram which plots equal lines of equal entropy against air pressure (altitude)?
Why not take 5 minutes and get out of this ignorance
Neil

135. Willis Eschenbach says:

joshua Corning says:
January 20, 2012 at 12:08 am

… i will restate my thought experiment again.
Imagine gas floating around in a cloud in the vacuum of space. it is spread out and the interactions between the atoms in the cloud are sparse…now imagine that cloud being pulled down a gravity well of a planet. the gas gains no energy yet it is now under pressure….now the atoms are all close together and colliding and doing what atoms do when they are forced to be in close proximity to one another. Again the atoms energy has not changed. yet their temperature is higher.
see how that works?

Thanks, joshua. I do see how it works. And you are right, that will heat it … once. But you cannot get continuous work out of that.
You can’t get work out of gravity. I understand the lure of perpetual motion, of a wheel endlessly turned by gravity, but it can’t happen. Gravity is a force. Either you are moving against it or with it. But it is a zero-sum game (actually it’s a loss). If I start at my house and walk down the hill and walk back up, the energy gained on the walk downhill I lose on the way back up. Plus friction loss, to add insult to injury. The three laws of thermodynamics say you can’t win, you can’t break even, you can only lose.
Sure, as in your example, things pick up kinetic energy when they fall in a gravitational field, which in a gas is temperature. But if you want it to happen twice, you have to move them against the force of gravity back up high so they can fall again. No way to come out ahead doing that.
Regards,
w.

136. Bryan says:

Tim Folkerts says
“The simplest and most convincing argument ended up being your same perpetual motion approach. You could run an insulated copper bar from bottom to top. This bar does not have the lapse rate effect. (Or use another gas that would have a different lapse rate because it has a different heat capacity). The copper should have the same temperature at top and bottom. If the gas had a different temperature, would could use this temperature difference to continually run the sort of heat engine you suggested.”
Tim go one stage further and source any real heat engine connected by real copper connections of one kilometer in length for a 9.8K temperature difference.
Factor in the resistance of the copper.
Who’s to say that one kilometer of copper will not have its own gravitational/thermal effect with its own value?
Indeed perhaps all this is in accordance with the second law
Maybe you can now see why an experiment to settle the isothermal/adiabatic distribution has never been attempted.
Its interesting that Claudius (who supported the isothermal conjecture) dropped the second law proof later on in life

137. jorgekafkazar says:

Willis: Sorry to have confused you. WordPress doesn’t allow the use of symbolic logic symbols here. I thought you’d immediately see the problem. In essence, you state:
1. “If [the isolated system is in its lowest energy state]{B} THEN [it cannot perform work]{not W}”
2. “If [the isolated system…is warm at the bottom and cold at the top]{D} THEN [it can perform work]{W}”
3. “[The isolated system cannot perform work]”{not W}
4. “therefore [the isothermal state…is the lower of the two energy states,]{J}”
Simplified even more, your argument boils down to:
1, if B THEN not W
2. if D THEN W
3. not W,
4. therefore J
But what you’ve proved, so far, is simply “not D.” (I can think of another state which can’t perform work.) For the argument to be valid, you must establish
1a. if not D THEN B, as well as
1b. if B THEN J, and so forth, 2., 3., 4., as you state.
Sorry for the confusion. I looked for the symbols for quite a while before giving up.

138. joshua Corning says:

“The Jelbring thought experiment concerns a closed system, with no energy going either in or out. I don’t recall saying the earth could not orbit the sun, you’ll have to cite that. In any case, that’s an open system.”
Atoms of high energy will be able to climb higher against gravity in the column then atoms of low energy. Energy is not going in and out but atoms still run into one another within the system right? and at any given time some atoms will whack into each other harder, simply by virtue of angle and velocity, then other atoms right?
If low energy atoms can only be at the bottom and high energy atoms can be anywhere in the column simple addition should tell you there will be more atoms at the bottom then on the top.
If there are more atoms on the bottom then the likelihood of those atoms (even though on average they are of a lower energy then the top) hitting your thermometer at the bottom then there is of them hitting the thermometer at the top. ie the temperature will be higher on the bottom then on the top.
You are confusing temperature with heat.

139. Robert L says:

Hi Willis,
I think the thermocouple analogy is broken. In order to extract energy from a thermocouple, it is true there has to be a temperature difference, but there has to be heat to operate the thermocouple pair. The top thermo has no ‘sink’ and as a result would simply get warm by conduction, from the lower thermocouple.
It your hypothetical isolated planet the atmosphere would become Isothermic. My reading of N&Z is that an input of energy is required to maintain the gradient. The mechanism is unclear, however ignoring KE, PE and convection is as foolish as expecting gravity to do all the work (pun intended)
Cheers
Robert

140. Bryan says:

Willis says
“To the contrary. Thermal equilibrium simply means that the objects have stopped exchanging energy because they are at the same temperature. This happens all the time.”
No at equilibrium they exchange equal quantities of energy

141. joshua Corning says:

“But you cannot get continuous work out of that. ”
yes you can. An object in motion will to stay in motion. Atoms don’t stop…they don’t have wind resistance, they don’t get tired, they just keep going and going and going, and as you stated no energy comes in and no energy goes out. So those atoms cannot transfer energy out…ever. they will bounce around in your column until the end of the universe and they will segregate out into a pressure gradient simply by virtue of the fact that at any given time some atoms will have low energy and some will have high energy…the low energy atoms stay close to the bottom while higher energy ones will be everywhere….thus you get high pressure at the bottom and low pressure near the top….a thermometer will measure this gravity induced pressure gradient as hot below and cold on top simply because more atoms will hit the thermometer on the bottom then will hit it on top.

142. Willis,
Firstly, thank you for the courtesy of your response. It is encouraging that we are able to set aside non-scientific issues that hang between us and conduct scientific debate rationally and reasonably.
Some preamble, and then some science.
You said to Lucy that
“time is what you don’t have. The clock is running, the elevator speech for N&Z is way overdue.”
Nobody is king of the clocks. Lucy and I are not sales people with obligations to meet targets within timeframes or elevators. Paradigms don’t change overnight. Resistance to the theory of plate tectonics continued for as long as the old guard were in tenure at their institutions. Time must be spent in evaluating new theories properly, not concertina’d into a gish gallop of instant rebuttal and ‘counterproof’.
A more relevant example than plate tectonics is the Loschmidt vs Maxwell and Boltzmann debate regarding thermal gradients matching the theoretical dry adiabatic lapse rate in equilibrium atmospheres subject to a gravitational field. It’s been going on for over a hundred years without resolution and we don’t need to force a conclusion within the next few days just because it has been thrust to the centre of the stage at the moment.
OK thanks for reading that, lets address some science.
Willis Eschenbach says:
January 19, 2012 at 6:26 pm
If an energetically isolated system is in its lowest energy state, it cannot perform work.

Agreed
If the isolated atmosphere in Jelbring’s thought experiment is warm at the bottom and cold at the top, I can stick a thermocouple into it and use the temperature differential to generate electricity to perform work.
Excellent, a proposed experiment. Let us know the result. I think you’ll find that even as a thought experiment it doesn’t work out though. Peter Berenyi emailed me that argument and I sent him my disproof. He hasn’t got back to me in the two days since. I’ll post it in a separate comment if you are interested in defining your setup.
As Tallbloke points out, the second law says an isolated system can only move towards a lower energy state. That means Jelbring’s thought experiment must inexorably move towards the isothermal condition as its equilibrium state.
No, as we’ve been saying all along, as have other people on this thread, at the lowest energy state, molecules at the top of the atmosphere have the same total energy as those at the bottom, but less of the total is available as kinetic energy which manifests as heat via collisions because more of the total energy is locked up as gravitational potential energy.
Since Jelbring claims an adiabatic state will obtain at equilibrium, his hypothesis is falsified.
If my statement above is correct, or if the equivalent macroscopic arguments provided on this thread and by Jelbrings 2003 paper are correct, then this statement is false.
Willis Eschenbach says:
January 19, 2012 at 9:21 pm
Jeremy says:
Gravity has NO AFFECT ON TEMPERATURE.
How many times must it be said.
You people are reading science fiction.
You have to do WORK to create a change in temperature – this is basic thermodynamics!!!!
If an object falls in a gravitational field then potential energy will be converted to kinetic energy which will create heat. However a stable column of air in equilibrium does not create any energy or heat.
Thanks, Jeremy. You are a hundred percent correct, gravity can’t do ongoing work to change the temperature

Jeremy and you are 100% wrong. Work is done by energy. Gravity is not a type of energy, it is a force. It cannot and does not need to “do ongoing work”. Nor is a change in temperature under discussion. Gravity, via the pressure profile it induces in an atmosphere, and considering the compressibility of the medium, causes the denser per unit area of the atmosphere near the surface to be warmer than it is at higher altitudes. g/Cp
If you are fighting basic ignorance of science, you will be deluged with ignorant people. Not much I can do but just keep putting the facts out there.
Certainly there are a host of much more sophisticated threads, and those tend to attract a more scientifically literate commenter. But when you are discussing “gravito-thermal” theories …

This is an ad hominem attack which has no place in scientific discourse.

143. markus says:

“joshua Corning says:
January 20, 2012 at 12:08 am
but when atoms are compressed by gravity as in an atmosphere then no energy is used to compress it”.
Probably be better to say, “then no energy is used to compress it, other than the potential energy of its mass.”
IR is (forced) employed into potential energy viz conduction of paired electrons around a molecules covalent bond, heating its chemicals, and adding kinetic energy to its energy budget
.
The adding of kinetic energy to mass causes heat, because of the collisions and transfer of the Atmospherically Thermally Enhanced kinetic energy that has been temporarily employed by the energy of mass.This heat is enhanced at higher pressures.
The energy budget of atmospheric trace chemicals should equal the square of its mass plus its employed kinetic energy.
And all the UW IR, DW IR, IR from enhanced mass, are just mixing gases in a pot up to re-radiation when kinetic energy of mass returns the employed energy to space
I have confidence in the N&K equation describing this phenomenon.
..

144. Michelangelo says:

Fascinating stuff in all these comments ..As a reader I especially liked the ones posted by ed_b , Ian H and I found the intriguing question why there are no PV-cells exploiting the energy supposedly radiated from the GHG:s during night by Richard Vernay very reveiling.

145. Bryan says:

Nick Stokes say
“When the lapse rate is below the dry adiabat (toward isothermal) it is referred to as convectively stable. Above the adiabat, it is unstable. At the adiabat, it is neutrally stable. ”
At the adiabat the parcel of air has no unbalanced force.
It can move up or down at constant speed or stay stationary.
This condition is called the neutral atmosphere and it can be surprisingly stable at night.
In dry conditions the gradient will be – 9.8K/km.
So its not correct to say that in OUR troposphere, the air will become isothermal if still.

146. Hoser says:

That’s an awful lot of talking people. So? What did you come up with?
Let’s try this again.
1) Sun heats surface. Some heat goes into land and sea, below the surface.
2) If an atmosphere is present, hotter areas are cooled and the heat is transported elsewhere and not radiated away as quickly.
3) After the sun goes down, the latent heat begins to radiate away. However a lot of energy remains below the surface and takes time to reach the surface.
4) If not all of the energy absorbed during the day is radiated away, then the surface will start off warmer the next day.
5) The average surface temperature continues to rise until the surface is able to radiate in 24 hours the same energy it absorbs during the day.
At least on land, the key difference between the Earth and the Moon is the atmosphere. On Earth the hot surface is cooled by air and therefore is unable to radiate as efficiently (because it was cooled). Cooler (shaded) areas are warmed by the heat transferred to the air by conduction from the warmer locations. On the Moon, shadowed areas radiate to 3K and are very cold. The Sun can heat surface rocks and these will get hotter until they are able to radiate efficiently the same amount of energy they absorb. No heat is transfered from one location to other places on the Moon. It should be no surprise the Moon’s surface cools rapidly after sunset. Although water is interesting, it seems not the driving factor given the data from planets and moons we saw a few weeks ago.

147. A recent BBC TV programme on the Earth’s core featured a claim by some scientist that the strength of the planet’s magnetic field has been falling significantly for the past 170 years. If true, might this tie in with the Svensmark hypothesis that changes in cosmic rays hitting the atmosphere affect cloud cover? Might one of WUWT’s resident brainboxes look into this and see if it has legs?

148. Same answer as I gave early in the “Matter of Gravity” post on January 14, 2012 at 2:45 am

149. John Marshall says:

Your argument about a heat engine using heat difference not working has been countered by the Norwegians who had a power station off coast in the Atlantic using the heat difference between water layers. It produced 60Mw, until the first severe winter storm when it sunk without trace.
The gravitic heat is better called adiabatic heat by compression which does exist and is the principle used by many machines used daily by everybody. It would happen in a planetary atmosphere because that is open to space and has free movement to all sides. there would be vertical movement due to convection and atmospheric pumping between day and night sides due to temperature difference/heat loss rates. Also your column, despite being at the same temperature, would not have the same heat content at the top compared to the bottom because gravity would introduce a density differential, A Km high enclosed column of air does NOT represent an atmospheric column by any stretch of the imagination.
I also ask my Jupiter question again. Why does this gas giant radiate more heat than it receives from the sun. your argument above makes this impossible.

150. Birdieshooter says:

My reply to all the questions raised above on both sides is WWES…….What Would Einstein Say? I would genuinely like to know. I wonder if he would have enjoyed these blogs. Anyone channel him lately?

151. gbaikie says:

“George Turner says:
January 19, 2012 at 9:20 pm
I have a follow-up thought experiment to my previous comment.
If flipping the air column upside down doesn’t require an input of work and returns the column to the dry adiabatic lapse rate, then the dry adiabatic lapse rate must be the column’s thermal equilibrium because a system cannot be shifted from thermal equilibrium without an input of work.”
I am sure what would happen. It seems you going heat the top when reaches bottom- and that heat isn’t going to get back to the new top.
Let’s move to orbit, where you could spin it [forever], and you have gravity gradient- the length column will make lower part travel slower than upper part. You will have gravity- gravity gradient in “free fall”.
Of course spinning will also add artificial gravity.
As I said you will heat the lower end- and therefore cool the gas.
So how a way to cool gas.
Now, let’s insulate it somehow.
Hmm. Use water instead of gas.
So without spinning water will cover entire inside [water tension] and will end up at lower end, mostly. Start slow rotation, and water will run to to middle then new bottom.
It seems that will affect the orbit somehow:).
But question is whether cools.
It doesn’t seem to. Back to air.
A new question is how fast would air move.
It’s going to fall, so it’s going to move fairly fast.
So back to surface again [or be some orbit and have respectable amount gravity gradient-big column]
The vacuum end when rotates to ground will “suck” the heavier air
and heavier air will fall- and this is going to be violent- as in supersonic.
So, there will be good mixing of the air- because the hot air going go straight up,
or break your machine.
You going to cause the air to become more directed.
It seems is you made air more balance in it’s direction- every molecule stopped another other molecule you get colder temperature.
But seems that if you start with cold air you could get hot air- and the more vacuum the better:).
One problem is normal atmospheric air isn’t balanced in terms of weight- the bottom is a lot heavier than the top.
So work is being done by rotating it.
So question is how small can make this thing and have do something. 1 km long seems challenging. But if used colder air and have vacuum at top, it seems something smaller is possible.
If it was 5 km in length falling velocity is somewhere around 500 mph, which somewhat interesting- but smaller are going make a little bit of wind. So entire atmosphere excitement, and 5 km maybe somewhat interesting, but probably something even bigger in space environment and using gravity gradient- might actually do something useful..

152. David L says:

Your first thought experiment sounded like Mawells Demon in which a gas can be partitioned into a hot side and a cold side by a force (a demon) that only allows high kinetic energy molecules to move in one direction and excluded the slow ones. In this case gravity is the demon.

153. Bill Hunter says:

I still don’t like your “perpetuum mobile” argument and a claim it violates the law of conservation.
I am not a physicist, but instead a logician. As I understand it physics claims energy cannot be destroyed. Thus it cannot be used up just converted and lost.
Jelbrings model according to my reading encapsulates energy and does not allow any to exit the atmosphere. So while you talk about light forever, if that energy is manifested as light and its always light where does it go when it cannot go anywhere?
Logically it seems to me the only issue is whether the atmosphere would be isothermal or not.
If isothermal then Jelbring is wrong and gravity does not cause the lapse rate and if the lapse rate exists at internal equilibrium he is most likely right.
I tend to think, but could be wrong, that for molecules under less pressure with the same temperature need to contain more energy.
So the question is what equilibrium is, is it energy or is it temperature. Personally I like the basal concept that its energy and not temperature but I have not wrapped my mind, or perhaps warped it, with Caballero.

154. A physicist says:

There are some terrific quotes by Richard Feynman in his Nobel Lecture The Development of the Space-Time View of Quantum Electrodynamics, that bear on these issues of thermodynamics:

We are struck by the very large number of different physical viewpoints and widely different mathematical formulations that are all equivalent to one another. The method used here, of reasoning in physical terms, therefore, appears to be extremely inefficient.
It always seems odd to me that the fundamental laws of physics, when discovered, can appear in so many different forms that are not apparently identical at first, but, with a little mathematical fiddling you can show the relationship. … There is always another way to say the same thing that doesn’t look at all like the way you said it before.

What we teach our engineering students is that you don’t really understand a phenomenon until (1) you can analyze it in more than one framework (formalism), and (2) within each framework, you can present it as an picture, an equation, and a numerical computation, and (3) you are able to unite all these frameworks within an encompassing narrative, that dovetails with other folks’ time-tested narratives.
With regard to thermodynamics and transport theory (which is broadly what this WUWT topic is about), an historically recent and very broadly applicable framework regards thermodynamics and transport theory as (essentially) the study of the geometry of flow on manifolds, specifically the study of Hamiltonian dynamical flows on manifolds that are equipped with a symplectic structure.
One great virtue of the symplectic approach to thermodynamics and transport is that it naturally encompasses both classical and quantum dynamics. A pretty significant downside, though, is that it takes a full year to learn the basic ideas and notations of differential geometry, in terms of which the whole framework is given.
What the resulting geometric dynamical frameworks predicts, though, is simple. If we computationally model the atmosphere (by a brute-force numerical calculation of molecular dynamics) as a cloud of particles in a gravitational potential, such that the particles bounce off each other elastically (with each collision conserving both energy and the number of particles), and the distance between collisions is small compared to the height of the atmosphere, and we do not “stir” the atmosphere with radiation heating at the bottom (or allow any other external influence to do work on the particles), then we will find (from the brute-force numerical codes) that the kinetic temperature of the particles is constant from top-to-bottom (note: the Wikipedia page the kinetic theory of gases has a picture of this kind of simulation, which are described in-depth in the well-respected textbook by Frenkel and Smit, titled Understanding Molecular Simulation: from Algorithms to Applications).
The dynamical geometer will argue as follows:

“We don’t even have to write that brute-force numerical code! Because we know in advance what the answer will be, by the following reasoning: if we consider the atmosphere as a stack of thin layers, and we allow each layer to exchange both energy and mass with the layers above and below it, and we remember to offset each layer’s chemical potential (the thermodynamic potential associated to mass exchange with adjacent layers) by that layer’s gravitational potential, then we appreciate that any atmosphere so modeled necessarily will evolve to an isothermal equilibrium, without regard for the details of the particle interactions.”

Summary: The folks here on WUWT who conceive that the gravitational potential gradient of the earth’s atmosphere has to induce some kind of thermodynamic gradient are 100% correct—but that thermodynamic gradient is a gradient of pressure (or equivalently, of chemical potential), not of temperature.
If these ideas sound kind of complicated and subtle … well, they are! Mistakes are very easy to make, and that is why it is prudent to evolve multiple independent explanations (pictures, analysis, numerics) as a cross-check on any given calculation.

155. Bill Hunter says:

A final thought when you have an equilibrium you need energy to change it. Thus our Stygian friends cannot tap into the equilibrium and generate light, they need energy to throw it out of equilibrium or if that energy is manifested as light to change the lighting arrangement concentrate it, focus it, or do any work with it.

156. re perpetual motion machines, we can say that there is ‘perpetual’ motion in our universe, such as orbits, bigband expansions and the like. how many motions are we undergoing at the moment ? 5 ?
If it’s energy for work you are seeking, then the best perpetual producer of energy on our planet might be it’s magnetic field. the findings of Nikola Tesla are to be considered. wiki has a reasonable summary. I am led to believe that I can access the electrical differential between 2 points separated by height, enough for a domestic supply.
my view is that there is much to be said for domestic solutions to energy requirements, passive solutions in the main.
getting back to the flow of energy, matter, temperature and gas atmospheres, bottled and otherwise.
heat is associated with increased molecular activity, ditto for pressure and molecular activity. we have bonding processes, chemical aggregations, there’s an evolution of structure. certainly our systems are extremely dynamic (large energy packages) with a myriad of structures – guess a number.
entropy – the eventual breakdown of structure and atoms. our little atom no longer has the energy to maintain it’s structure. pop ! it stops, electrons touch protons and neutrons, probably losing their shape. the molecular structure loses it’s space, and the volume of the matter reduces by a massive amount. in our astronomy class we would marvel at how a battleship could fit into a matchbox if you removed the space between the atoms. so we can ‘witness’ the reduction of volume at the earth’s core, I don’t know the pressure or gravitational measurements at that place, nor electrical discharge. obviously the process depletes the fuel source and imploding occurs. so we are supported from below as well as from above.
I do believe in using a multivariable approach to solving problems, rather than isolating certain variables.
I think we can generally expect more of the same; cosmic rays, sun bursts, volcanic eruptions, convection currents, and the odd meteorite.
cheers !

157. Bomber_the_Cat says:

anna v says:
January 19, 2012 at 10:36 pm
“Could one do the experiment using water as the fluid?”
Yes, you could, but there is no need. We already have some; they are called oceans and lakes. The water at the bottom of the ocean is under great pressure. Dos this make it warmer? No, we all know that warm water rises. The hotter water is at the top. You can verify that in your bathtub. So pressure does not cause warming. QED.
So what is the difference between water and the atmosphere? We all know that warm air rises too, just like warm water rises. But in the atmosphere the cold temperatures are at the top ( up to the tropopause). So what is different? I could indicate this in one word! – but it is best left as an exercise to the reader. Some individual thought will promote a more general understanding.

158. What Bart said.

159. Joe Born says:

As others have observed above, Willis’s argument has a then-a-miracle-occurs step: he postulates a heat engine that is free of the gravity to which the gas column is subjected. He skipped the the step where Harry Potter removes the gravity from the heat engine’s location.
The mean single-molecule kinetic energy in a system of the type Willis describes is (3E/(5N-2))(1-mgz/E), where N is the number of molecules, E is total system energy, m is molecular mass, g is the acceleration of gravity, and z is altitude. If you put numbers to it, you see that the lapse rate is exceedingly small but non-zero.

160. DirkH says:

Imagine Willis’ container to be finite, and filled with air with a pressure of 1 bar, and being in his isothermal condition, with constant pressure and temperature throughout, as required by the Ideal Gas law. Now consider a second container on topo of it, with infinitesimal height, with vacuum inside. Now we remove the lid that separates these two containers. Brownian motion will make gas molecules dissipate into the vauum but the gravitational field pulls them back; and a pressure gradient develops, and with it, according to the Ideal Gas law, a temperature gradient.
And that is the stable configuration, not the isothermal one. What we end up with is the dry lapse rate, assuming that we have no radiative energy redistribution.
The notion that in equilibrium, there must be the same density of kinetic and potential energy in every partial volume must be false, because it would require infinite temperatures at the top end of the gas column.

161. Joe Born says:

I failed to mention that the formula I gave above applies to monatomic gases.The factor on the right is different for gases with higher degrees of freedom, but the overall expression remains dependent on altitude.

162. Another never ending debate is seems. How about escape velocity?
The atmosphere of a planet cannot be completely isothermal since the velocity i.e. energy of the uppermost molecules at some point would exceed escape velocity. Venus and Earth both have roughly the same mass so they would have the same escape velocity. If Venus is a perfect greenhouse effect, since its black body temperature is 184K (65Wm-2) or -89C, the Earth would have the same constraints, -89C, Anyone noticed the minimum temperature of the Antarctic lately?
Gravity places limits on atmospheric energy, if gravity fluctuates it would change those limits. Earth’s gravity doesn’t fluctuate enough to have a significant impact on temperature at the surface. If someone would like to show that Earth’s escape velocity changes enough to have an impact on surface temperature, I would love to see it.
Since mass is energy, Gravity and the Geomagnetic field both help retain atmospheric mass, perhaps a mass balance would be an interesting exercise?

163. Johan i Kanada says:

This argument should be possible to resolve in 5 min by any reputable physics professor.
So why not invite one (or several) to comment/clarify?

164. In 2010 I had a discussion about Hans Jelbrings theory with John Wallace, atmospheric scientist at the university of Washington. He wrote me:
“To understand how radiative transfer influences surface temperature, one needs to go beyond the concept of the adiabatic lapse rate and consider an atmosphere in “radiative-convective equilibrium, as discussed on p. 421-422 of the 2nd edition of our textbook. In such an idealized 2-layer atmosphere, the lower layer, which is comparable in depth to the troposphere, has a lapse rate equal to the adiabatic lapse rate . Two points emerge from this simple analysis:
(1) Were there is no greenhouse effect, the lapse rate in a planetary atmosphere would be isothermal (i.e., temperature would not change with height. In this case, the dry adiabatic lapse rate would be unchanged from its present value, but it would be completely irrelevant to the interpretation of the observed lapse rate.
(2) Greenhouse gas concentrations have no effect on the adiabatic lapse rate in the lower “convective” layer, but they determine the depth of that layer: increasing greenhouse gases increases the surface temperature of the planet not by changing the lapse rate, but by deepening the convective layer. “.
I think that’s it.

165. John Marshall says:

There is a difference between temperature and heat. whilst temperature is a measurement of heat we need to know the specific heat of a substance to know how much heat is present. So this imaginary Km high column could have identical temperatures top and bottom but heat content will be different due to the density difference.
I think I have said this before. Sorry for a boring repeat.

166. Alexander Harvey says:

Hi Willis,
I am pleased that you have retruned to this.
First, something I said on the previous thread was both hasty and in error. In terms of Potential Energy the change from isothermal and the DALR modes does not lower the centre of mass of the atmosphere as I speculated, it is not energetically prefered as I suggested, in fact it makes no difference as far as I can tell. Now on to more interesting things.
As I see it, you now expose their model as being inviolation of both the 1st and 2nd Laws. That is the way I have seen things.
Having derived the isothermal as being the prefered profile, a way is open to you to do something rather useful, in my opinion. That is to determine the GHE without appeal to the notion of “heat trapping”, which I consider to be bogus and generally unhelpful.
The naming of the GHE, is I suggest, due to our inhabitting the surface. To illustrate this and my issue with “heat trapping”, I will pose the following question in an idealised atmosphere (see below for part of the idealisation).
In terms of just the atmospheric part, does the addition of GHGs move an atmospheric system as a whole towards a warmer or cooler state, or make no difference?
My preference, or prejudice, would be to say that it tends to cool an atmosphere as a whole but also redistribute energy towards the DALR profile. The notion of a GHE being solely a POV issue. For a denizen of the upper atmosphere it might be termed the IBE (Ice Box Effect). I like to put it this way for I find that everybody hates the notion. It seems clear to me that the effect of adding GHGs when viewed from an atmospheric system perspective is to produce a strong cooling tendency that is acted against by a strong response in the form of sensible and latent fluxes.
There is a level of idealisation going on here, Notably an absence of SW absorption and the production of warming in the stratosphere of our Earth. For those who can put that to one side, I think that there is an opportunity for insight into an origin for of the surface GHE in terms of an overall cooling tendency. The complication due the real stratospheric warming and the way that may contribute to the production of the tropopause and in the determination of its height puts the question of whether the real atmosphere as a whole would actually warm, cool, or stay the same into some doubt. That is by the bye in terms of the idealisation I have assumed.
I view the GHE and the IBE as two inseparable sides to the same coin. Compared to the non-GHG isothermal case where the whole system assumes the SB equillibrium temperature, the addition of GHGs causes the surface to be warmer (GHE) but crucially the upper troposhere (on the real Earth) to be cooler (IBE). If people must have “heat trapping” I say they must also have “heat releasing” but I would rather they simply dropped that metaphor altogether. GHGs couple the atmoshpere to the radiative field and whether a cooling or a warming takes place locally, is determined by the spectra of the GHGs, their local density, the local temperature and the local strength of the radiative field at each frequency.
I don’t expect anyone to agree with this, amongst skeptics it may be viewed as a AGW trojan horse, amongst the staunch AGW dogmatists it seems to be viewed as deeply unhelpful perhaps largely due to the loss of the “heat trapping” metaphor, or simply wrong. Hopefully it is a POV that people can have fun with and might just break down some barriers to thinking about GHGEs (Greenhouse gas effects).
It is not all about warming.
Alex

167. Willis,
please get back to me via email, not here – I just don’t have the time.
Put simply, ignoring the electrical input into the earth system will lead you down many, intellectually attractive, paths.
Have a look at plasma physics and its applicability to your topics – you might be more than surprised,
Louis

168. LazyTeenager says:

David says
The air moving up and down exchanges potential energy (PE) for kinetic energy (KE). The air moving down loses PE but gains KE, and vice versa for the air moving up.
——-
I have not entirely digested the article but an important consideration may be that Willis is referring to an atmosphere that is in equilibrium, without external energy sources. This means that there is NO motion of the air.
David you are referring to air in motion. Which means there must be an external energy source to keep the air in motion.
So David and Willis are describing different situations.

169. markus says:

An inverted cone 1klm in DIA, 5klm high, 10m DIA at top, on stilts above water, so atmosphere can enter down low.
Intoduce Co2 @ 5,000ppm with a Co2 drip feed relative to the life of atmospheric Co2. Headed by a turbine.
Just like GH theory, the Co2 enriched atmosphere inside must warm more than the atmosphere coming in below, and because of thermodynamics the heat at the top will turn that turbine.

170. MarkW says:

I’m looking at the problem from a different direction. That of stability. Think of a column of air running from the ground to space. The temperature of this column of air at the very top is fixed. It is the temperature of space itself. As you descend through this column of air, the rate at which the air warms is determined by the lapse rate. Anytime a particular patch of air gets above the temperature determined by the lapse rate for that depth, it immediately becomes more boyant than the surrounding air and starts rising. It cools, but it still remains above the temperature of the air in it’s new surroundings. It rises until it reaches the top of the column, where it radiates it’s excess heat out into space.
This is not a perpetual motion machine, because it isn’t gravity that is causing the heating. It’s the sun. Take away the sun and quickly the whole column of air freezes. Increasing or decreasing the amount of energy coming from the sun will increase or decrease the total energy in the column of air, but the result of this is and expansion or contraction of the air, causing the column to grow or shrink. When the column expands, the average density of the air changes, which decreases the lapse rate. However the temperature at the top of the column and the bottom of the column remain the same. Decrease the energy from the sun, and the density of the air increases, and the height of the column decreases, but the temperature at the top and bottom still remain the same.
This relationship stays true until air cools to the point that it becomes a liquid.

171. Bill Illis says:

The basic assumption of the radiation theory is that as mass gains energy when it enters a gravity field, all that energy will eventually be radiated away to space as EM radiation. This could take some time but for a gas it wouldn’t be that long.
All the thermal energy gained from gravitational potential energy is then eventually radiated away to space as EM radiation (give or take some cosmic background radiation re-entering the system).
Therefore: Gravitational Potential Energy = EM Energy
Therefore: the gravitational energy will eventually be radiated away to space – for gasses this should be relatively fast.
Well, that now gives us the theory of everything.
Except gravitational energy is not observed to decrease/radiate away over time unless the mass declines so the basic assumption is not complete. Thermal energy radiates away, but gravity does not.
That then implies:
– when an object which has gained energy in a gravity field loses EM energy through EM radiation, it must gain that back from the gravity field; or,
– gravitational energy is only interchangeble with EM/thermal energy at a limited level. It must be so small that we cannot detect a decline in gravity. Higgs bosons do not directly turn into EM photons, or only rarely; or,
– whatever gravitational energy that is not converted into EM energy remains in the system and is what we perceive as gravity.
There are all kinds of issues with this picture that are not understood at all.

172. Birdieshooter says:
January 20, 2012 at 2:30 am
My reply to all the questions raised above on both sides is WWES…….What Would Einstein Say? I would genuinely like to know. I wonder if he would have enjoyed these blogs. Anyone channel him lately?

He would say:
“If Jeremy and Willis are right, there goes relativity!”

173. steveta_uk says:

Willis (or Dr Brown) the case for the isothermal cylinder seems to be fairly well established.
But on Earth, any given area on the surface has a conical section of atmosphere above it, and by my sums, I’d expect that if you have 15C at the surface, you’d expect to see about 13C at 15km simply due to the larger volume.
Not sure this has any implications for the overall argument or not.

174. Rob said, “(1) Were there is no greenhouse effect, the lapse rate in a planetary atmosphere would be isothermal (i.e., temperature would not change with height. In this case, the dry adiabatic lapse rate would be unchanged from its present value, but it would be completely irrelevant to the interpretation of the observed lapse rate.”
That is not entirely true. The lapse rate would attempt to approach isothermal. Even without “greenhouse effects” there is conductive heat transfer. The viscosity of the lower atmosphere would increase to improve conductive heat transfer reducing convection. Gravity would limit the amount of energy that could be contained in the atmosphere. The energy of the upper most molecules in steady state would be less than gravity imposes for the escape velocity of the planet. This is another, “all things being equal” example.
“(2) Greenhouse gas concentrations have no effect on the adiabatic lapse rate in the lower “convective” layer, but they determine the depth of that layer: increasing greenhouse gases increases the surface temperature of the planet not by changing the lapse rate, but by deepening the convective layer. “.
Another all things being equal example. “Greenhouse Gases” have differing thermal conductive properties, molecular weights and heat capacities. The “mix” in a mixed gases environment has more than just radiant effects.
Conductivity is generally assumed negligible in radiant atmospheric physics. The possibility that it is not negligible, reflects poorly on the estimates of the “radiant” portion of the ATMOSPHERIC EFFECT.

175. Frank says:

Willis,
I think Dr. Brown’s thought experiment makes a mistake by linking the temperature to the vertical component of the molecule speed, only, when he says: “On average, just as many molecules move up, with exactly the same velocity/kinetic energy profile, as move down, with zero energy transport, zero mass transport, and zero alteration of the MB profiles above and below, only when the two slices have the same temperature”.
If there is a difference in horizontal speed (i.e. wind) between the layers, the temperatures can be different while the layers do adhere to all of the conditions mentioned in the quote.
On another note, Willis, when you tell Jeremy: “You are a hundred percent correct, gravity can’t do ongoing work to change the temperature”, I hope you’re not forgetting that the Earth does negative work on the molecules going up, which in equilibrium cancels out the positive work being done on the molecules going down, the net energy effect being zero.

176. Joe Born says:

Bart: “Without radiating gasses to draw the heat energy away, the atmosphere of a planet is like an ideal electrical capacitor hooked up to a constant voltage source”
I know you changed this to “constant-current source,” but, actually, you had it right the first time If voltage is temperature and the earth’s surface is the voltage source. An atmosphere of the type you describe would acquire energy from its source only when its temperature is less than the surface’s. Of course, the earth’s “voltage” isn’t constant, and its outgoing radiation provides a (highly nonlinear) parallel conductance, but that doesn’t detract from the point: the capacitor won’t pop.

177. Richard M says:

AusieDan says:
January 19, 2012 at 8:14 pm
We need a theory to explain why the surface temperature of the various solar bodies can be derived as a function of distance from the sun (solar radiance) plus near surface atmospheric pressure.

I’ve given it several times now. It’s called the standard GHE at its maximum. That maximum effect is determined by atmospheric pressure. Nothing else is needed. This conjecture explains all the data.
Now, why is there a maximum? I’m not sure, but it could be where the “cooling effect” of GHGs exactly matches the “warming effect”. The latter one is the only one climate scientists look at. The former one is what you get when a GHG extracts energy from the atmosphere and radiates that energy to space.

178. Luke says:

All right, here is my attempt at the elevator speech for what I understand the Jelbrings paper to be, based on the discussions here. I’m sure someone will find something wrong with it. It’s a little bit longer than Willis’ elevator speech, but I believe that his misses some crucial pieces.
* If left undisturbed in a gravity field, a tall container of air will stratify vertically, with the coolest temperature at the top and the warmest temperature at the bottom.
* In an undisturbed environment that column of air will eventually reach energetic equilibrium, meaning that any given cube of air will contain exactly the same amount of energy, whether at the top or the bottom.
* Because an air molecule at the top of the column (gravitational body) is further away from the earth (gravitational body) than a molecule at the bottom of the column, by the universal law of gravitation less force is being exerted on the molecule at the top of the column.
* Therefore the pressure at the top of the column will be higher than the pressure at the bottom of the column.
* It also then follows, according to the ideal gas law, that P1 * V1 / T1 = P2 * V2 / T2 where 1 is the top of the column and 2 is the bottom of the column.
* Therefore, when examining two identical volumes of air, one at the top of the column and one at the bottom of the column, the one with the greater pressure (bottom of the column) must also have a greater temperature for energetic equilibrium to have been reached.
* This property of an undisturbed column of air in a gravity field, is the cause of what we erroneously refer to as the “greenhouse effect”.
Willis, such a column would never be isothermic throughout the whole column of air. Instead, it would be isothermic at any given layer of the column. In other words any given horizontal slice parallel to the earth would be isothermic, but they would not be isothermic from one layer to the next. The faulty assumption necessary to yield an isothermic column is that the strength of gravity field acting upon any given molecule in the column is uniform throughout the column. It clearly is not, both theoretically and empirically.

179. Luke says:

Bomber Cat:
Real oceans and lakes are not a good facsimile for this thought experiment. The reason, their primary thermal input comes from the top of the ocean (i.e. the warming rays of the sun) because the depth of water does not allow the sun’s radiation to reach the bottom of the ocean floor to be absorbed and redistributed back upwards.
If you look at how a solar pond works (when the sun can penetrate to the black bottom) you see the warmer water at the bottom and the colder water at the top. The problem in your example is the lack of transparency of the ocean and an energy source at the top.

180. Why is the N Z paper called a gravity model? I always interpreted their model as a delay model. Sun heats the surface through a largely transparent medium. The surface heats this transparent medium though particle contact. Eventually this distributes through the transparent medium.
The delay in the heated surface to lose it’s temp because of the transparent medium allows the surface to heat more than it would without the transparent medium.
I read what was posted in this article that ignores any of the above as completely missing the point.

181. JJThoms says:

Consider a 10km long box 1m x 1m cross section of perfect insulating material (aerogel?). Coat the outside with 100% reflective material (to stop the aeogel radiating it will not conduct)
Fill it with argon.
Lay it horizontally 5km above ground level. It will of course be perfectly balanced
Leave it for a few days.
The temperature must stabilise so that all the gas is at the same temperature – there are no external influences on the gas and it cannot radiate and cannot conduct out of the box
Rotate it 90 degrees. (it will do some of the work itself as the argon compresses in the lower end and decompresses in the higher unbalancing the system.
When vertical the argon will be heavily compressed in the lower end and therefore much hotter and very decompressed and therefore cooler in the high end. In fact it will have the profie dictated by the lapse rate.
Leave this for a few months. Those warm and cool atoms of argon will be wizzing about in the box but they will be loosing no energy. All that wizzing eventually equalizes the temperature throughout the gas – the low pressure gas will have the same temperature as the high pressure gas.
There is no energy in or out to disturb this. Maxwells deamon is not in the box to sort the hot from the cold! the gas is isothermal.
It will stay in this state forever.
Now rotate the box through 180 degrees and magically the low pressure end becomes the high pressure end and therefore the lapse rate is re-established.
HOWEVER
You have just turned a box that is heavy at the lower end. raising it 10km up in the air, working against gravity. There has been much work done.
Leave the box for a few more months and the gas will again become isothermal.
BUT
The temperature will now be hotter than before because you put all that work in rotating the box.
You can continue this rotation untill the argon is white hot of course!
BUT
it only gets hotter because you put in work
Leave the box vertical for as long as you like and no work will be done. Gravity is static it does no work. If gravity maintained the adiabatic lapse rate temperatures the it would be magically operatinhg as a maxwell deamon.
By the way look up “vortex tube” for a way of separating hot and cold air! A maxwell deamon powered by compressed air.

182. Luke says:

As a follow-on to the solar pond comment I just left, I do not consider it a reasonable facsimile of the experiment either. I was only pointing out that there are bodies of water that violate the example of oceans and lakes. In order for it to be a reasonable facsimile, there would have to be no light source, i.e no sun.

183. Tim Folkerts says:

Tallbloke says: “No, as we’ve been saying all along, as have other people on this thread, at the lowest energy state, molecules at the top of the atmosphere have the same total energy as those at the bottom, but less of the total is available as kinetic energy …”
As has been stated many times in many way, science is not decided by consensus, and science is certainly not by consensus of non-experts. Of the people on this list who seem to have formal training in physics, the agreement seems quite strong that isothermal is the the equilibrium condition for the given thought experiment.
Among OTHER trained physicists I have consulted, that is ALSO the agreement for isothermal rather than a lapse rate.
For instance, they say:
“all of the following are true:
— Boltzmann distribution of kinetic energy
— Boltzmann distribution of potential energy
— Boltzmann distribution of total energy.”
This is in contrast to Tallbloke’s claim that ONLY total energy follows the Boltzmann distribution.
EACH of these separately will have the same distribution and the same temperature. I could also go into the rather involved discussion of the partial derivatives involved, like

               ∂S
β  = --------
∂E | N


but I don’t think it would help much in this discussion.
[COMMENT: I fixed the formatting, Tim, using the “pre” tags (for “preformatted”). WordPress ignores leading blank spaces. —w.]

184. Luke says:

Oops… I reversed on point in my elevator speech…
* Therefore the pressure at the bottom of the column will be higher than the pressure at the top of the column.
The whole thing should read:
* If left undisturbed in a gravity field, a tall container of air will stratify vertically, with the coolest temperature at the top and the warmest temperature at the bottom.
* In an undisturbed environment that column of air will eventually reach energetic equilibrium, meaning that any given cube of air will contain exactly the same amount of energy, whether at the top or the bottom.
* Because an air molecule at the top of the column (gravitational body) is further away from the earth (gravitational body) than a molecule at the bottom of the column, by the universal law of gravitation less force is being exerted on the molecule at the top of the column.
* Therefore the pressure at the bottom of the column will be higher than the pressure at the top of the column.
* It also then follows, according to the ideal gas law, that P1 * V1 / T1 = P2 * V2 / T2 where 1 is the top of the column and 2 is the bottom of the column.
* Therefore, when examining two identical volumes of air, one at the top of the column and one at the bottom of the column, the one with the greater pressure (bottom of the column) must also have a greater temperature for energetic equilibrium to have been reached.
* This property of an undisturbed column of air in a gravity field, is the cause of what we erroneously refer to as the “greenhouse effect”.

185. Warren in Minnesota says:

There must be some Peter Principle corollary or perhaps Parkinson’s Law of Triviality corollary with this discussion.

186. Joules Verne says:

Luke says:
January 20, 2012 at 5:41 am
“* This property of an undisturbed column of air in a gravity field, is the cause of what we erroneously refer to as the “greenhouse effect”.”
This conclusion is not supported. The temperature at the bottom of the column would be the same with or without gravity! Gravity merely trades off temperature for gravitational potential energy with increasing column height. That’s all it does. It can’t add or substract energy from the column, it can’t change the distribution of energy in the column, but it CAN change the distribution of sensible/insensible energy and that distinction is important because potential energy won’t save any brass monkeys from disfigurement.

187. A physicist says:

Here is a Car-Talk Puzzler-type question that (hopefully) will illuminate why Luke and other posters are mistaken.
A WUWT Puzzler
Alice has a cannon that shoots vertically, with a random initial vertical velocity, whose root-mean-square initial value is 100 meters/second, whose mean value is zero, and which is normally distributed (a Bell-shape curve).
Puzzler Remarks:
(1) on half of the firings, Alice’s shell shoots down into the dirt
(2) the other half of the firings, Alice’s shell shoots up-in-the-air
(3) a typical maximal height is (100^2)/(2*10) = 500 meters
(4) some shells fly higher, others lower
Puzzler Question: Of all the shells that pass the “X” meter height, what is their mean square velocity, as measured at “X” meters altitude?
Asserted Puzzler Answer: No matter what the value of height “X”, the shells that pass through height “X” have a root-mean-square velocity of 100 meters/second.
So amazingly, our “Puzzler Shells” do not “cool off” as they fly to higher altitudes. Rather, there are simply fewer-and-fewer of them.
As with “Puzzler Shells”, so with gas molecules: their temperature is independent of elevation, but their density decreases.
And that is my “elevator explanation” of Willis’ problem.

188. JJThoms says:

John Mason says: January 20, 2012 at 5:56 am
… The faulty assumption necessary to yield an isothermic column is that the strength of gravity field acting upon any given molecule in the column is uniform throughout the column. It clearly is not, both theoretically and empirically.
============
The force of gravity changes little over a 10km distance above the earth:
http://en.wikipedia.org/wiki/File:Erdgvarp.png
Surface g=9.81
10km g=9.78
less than 0.5% change

189. Tim Folkerts says:

Luke says: January 20, 2012 at 5:41 am
All right, here is my attempt at the elevator speech…
* If left undisturbed in a gravity field, a tall container of air will stratify vertically, with the coolest temperature at the top and the warmest temperature at the bottom.

You are starting from a wrong hypothesis. My first thought was also that this might be the equilibrium condition, but a bit of actual study of the issue made it clear this is wrong
“* This property of an undisturbed column of air in a gravity field, is the cause of what we erroneously refer to as the “greenhouse effect”.
If you start with a wrong postulate, then is is easy to come to all sorts of incorrect conclusions. For example, this property of an undisturbed column is ALSO what allows you to run a perpetual motion machine from this air column.

190. Joel Shore says:

John Marshall says:

I also ask my Jupiter question again. Why does this gas giant radiate more heat than it receives from the sun. your argument above makes this impossible.

Because Jupiter is a gas giant undergoing slow gravitational collapse. I.e., the thermal energy is generated by the conversion of gravitational potential energy. See for example the discussion here http://nineplanets.org/jupiter.html :

Jupiter radiates more energy into space than it receives from the Sun. The interior of Jupiter is hot: the core is probably about 20,000 K. The heat is generated by the Kelvin-Helmholtz mechanism, the slow gravitational compression of the planet. (Jupiter does NOT produce energy by nuclear fusion as in the Sun; it is much too small and hence its interior is too cool to ignite nuclear reactions.)

This is not happening for the Earth.

191. Paolo M. says:

“Gravity has NO AFFECT ON TEMPERATURE.”
As far as planet Earth is concerned, the correct statement would be:
Gravity has NO EFFECT ON POTENTIAL TEMPERATURE!
In a gravity field, with a costant source of energy (the Sun), in presence of two sinks (the Poles), the vertical profile of temperature would be that of the adiabatic lapse rate.
The presence of water, other GHGs and ozone makes the thinks more complicated, but vertical mixing can’t be ignored.
Of course gravity doesn’t make the difference between two planet, one with GHGs and the other without. It just rearranges the vertical distribution of absolute temperature (thanks to density), but not that of POTENTIAL temperature that would be costant. Actualy, potential temperature in our troposphere is higher aloft due to the release of latent heat after (mainly) wet convection has occurred

192. OzWizard says:

Willis,
N & Z have indeed produced a game-changer here and no thought experiment is needed to understand their ‘Unified Theory of Climate’. Simply stated, their hypothesis consists of their two key equations, (7) and (8).
The existence of a dimensionless ATE ‘factor’ does not imply that “gravity causes heating of the lower atmosphere”, in defiance of the 2nd Law of Thermodynamics. I believe the relevant science is nicely encapsulated in their (non-linear) equation (8),
Ts = 25.3966 (So + 0.0001325)^0.25 NTE(Ps).
That equation enables them to calculate the surface temperature (Ts) of ‘any planet with an atmosphere’, knowing only the TOA TSI (So), the surface pressure (Ps) on the planet and the dimensionless Atmospheric Temperature Enhancement factor (NTE).
The NTE factor for any planet is derived from observations already made (see N & Z, Table 1) and a thorough reassessment of the physics of what they term ‘grey body’ temperature (Tgb) of a real, airless planetary object (our own moon) – a conceptual physical model which is used in equation (7) to derive their NTE values.
The experiments have been done, the data have been analyzed; their ‘grey body’ temperature model and their simple regression are now out there to be pondered for veracity and significance.
The fact that nobody can explain “how it works” (to your satisfaction) is not a valid reason to try to demolish their hypothesis by thought experiments (which include unproven assumptions).
Try to understand it Willis, please. All your thought experiments are irrelevant unless you can demonstrate where their math, or their data, or their ‘grey body’ model, or their regression is wrong. To do that you need to understand what they have done and, by your own admission, you do not yet understand what they have done.

193. Tim Folkerts says:
January 20, 2012 at 6:06 am
Of the people on this list who seem to have formal training in physics, the agreement seems quite strong that isothermal is the the equilibrium condition for the given thought experiment.

Whereas the engineers and meteorologists tend the other way. And this is interesting, because it shows who has more common sense. 🙂
Tim, it’s no good appealing to Boltzmann when he is one of the protagonists in the unresolved dispute.
Loschmidt, Lagrange, Laplace, Jelbring and me vs Willis, you, Jeremy, Boltzmann and Maxwell
Outside, now!
lol.
I’m reading up on what happened between Maxwell’s formative thinking about classical molecular mechanics (engineers and meteorologists) and his part in the development of statistical mechanics (physicists and mathematicians) to see if I can find the key to this fascinating puzzle.

194. quondam says:

Last year this was discussed in a Climate Etc. thread. Perhaps a conceptually simpler Perpetuum Mobile machine can be constructed from two identical vertical columns of gases of different heat capacity, e.g. helium and argon thermally connected at their bases and totally insulated otherwise. If the lapse rate is an equilibrium property, there will be a constant temperature difference at the tops of these two columns. Making identical thermocouple connections between these points at the same gravitational potential, one has an electric potential difference and can then use this to dissipate energy. Energy is being extracted from both columns, cooling both while a constant temperature difference persists at the thermocouples.
If one is mathematically inclined, it is not a difficult exercise to start with a fixed volume of an isothermal, ideal gas and show that any perturbation of its density and thermal profiles leads to reduced configurational entropy, total energy held constant.
When one sees the expression “radiative-convective equilibrium” employed, it’s a giveaway that the writer is unconditionally misinformed. There can be radiative-convective steady-states, but any steady-state requires a constant dissipation of either mass or energy for maintenance. That the troposphere might be described as a steady-state implies such an energy of dissipation and, perhaps not too surprisingly, convective stirring takes a steady input ca. 240W/m^2 to be dissipated, but that’s reverting to pre-postnormal science.

195. DirkH says:

DirkH says:
January 20, 2012 at 3:54 am
“And that is the stable configuration, not the isothermal one.”
Looks like I misunderstood the definition of “isothermal” – and my explanation is in no contradiction to Willis’ isothermal configuration. So it seems Willis and I agree that we will observe the lapse rate as defined by the Ideal Gas Law. Sorry for any confusion.

196. DR says:

After 24 years of being inundated with “greenhouse effect” theory lectures, first from James Hansen in 1988 which those of us old enough to remember was quite a display of fear mongering (very convincingly so I might add), multiple documentaries on television and never ending use of the term since then in the media and science publications, the whole damn thing has evolved into an unfalsifiable hypothesis . Anyone can use the internet to find these “high school physics” descriptions of how the GHE works.
All I would like an answer to is why the very basic tenet of the GHE, that being the tropical troposphere should be warming at a faster rate than the surface, is unsupported by observational evidence. This was culminated by the debunking of Santer 08, perhaps the most dubious peer reviewed material released for public and scientific consumption since MBH 98. To keep the pseudoscience alive, scientists promoting the failed experiment tell us the observations must be wrong, not the “theory”.
I was fully convinced in 1988 of the “greenhouse effect” and it’s deleterious effects it would have on the earth, yet here it is 24 years later and it isn’t working as advertised. If anything, it is upside down.
There is something wrong with the GHE hypothesis as it has been promoted lo these many years.. I’m not qualified to enunciate what it is in technical jargon, but I don’t need to be an atmospheric scientist or physicist to know something is wrong. Does anyone else feel like they’ve been sold a lemon? Even here on WUWT,with the arguing going back and forth, the “theory” is no better explained or proven than it was 25 years ago.
“If it disagrees with experiment, it’s wrong”.

197. Tamara says:

Regarding N and Z, my understanding of it is this (could be totally wrong, IANAPhysicist):
When a star is accreting, gravitational contraction converts gravitational potential energy into thermal energy. It is this thermal energy which acts as an opposing force to gravity, preventing the star from collapsing completely. As the star gains mass, its gravitational attraction increases as does its thermal energy. At some point thermal energy becomes large enough that fusion occurs and the star becomes stable. What does this have to do with N and Z? As I understand it, they claim that they can estimate atmospheric temperature from the density of the atmosphere. A volume of air that is more dense has more mass than the same volume of air that is less dense. Therefore, shouldn’t the dense volume of air have more gravitational potential energy that can be converted to thermal energy? And, can we assume that any volume of air that is being contracted by gravity will have some thermal energy above the black/gray body energy?

198. Jeremy says:

richard verney
The affects of the tides and other orbital parameters will indeed affect the atmosphere. Work is indeed done in the thermodynamic sense of external force acting on a closed system. In fact the Moon and Earth system will experience a loss in Kinetic energy from the “gravitational drag” of tides. These are third or fourth or even higher order effects. Like variations of the trace gas CO2, the affect of these things on “atmospheric temperatures” are extremely small and inconsequential compared to radiative forcing from our Sun.

199. DirkH says:

JJThoms says:
January 20, 2012 at 6:03 am
“Leave this for a few months. Those warm and cool atoms of argon will be wizzing about in the box but they will be loosing no energy. All that wizzing eventually equalizes the temperature throughout the gas – the low pressure gas will have the same temperature as the high pressure gas.”
But according to the Ideal Gas Law, this is not possible. The temperature distribution must follow the pressure distribution so that PV = NkT
where P is the absolute pressure of the gas measured in atmospheres; V is the volume (in this equation the volume is expressed in liters); N is the number of particles in the gas; k is Boltzmann’s constant relating temperature and energy; and T is the absolute temperature.
http://en.wikipedia.org/wiki/Ideal_gas_law
They very fact that there is a vertical pressure gradient results in a temperature gradient.

200. Stanb999 says:

So in this mythical elevator….
First it has no sides. It has no top. The bottom can vary widely…. Density can be 50% different.
With temperature changes the hight as well as the width of the elevator can grow or shrink.
What is so hard to figure out? As the atmosphere has heat added it grows. This growing increases it’s surface area. This increased surface area. Increases the thermal exposure to the cold of space. It cools.
The atmosphere as well as earths temperature is self regulating.

201. mkelly says:

Jeremy says:
January 19, 2012 at 7:52 pm
Gravity has NO AFFECT ON TEMPERATURE.
How many times must it be said.
You have to do WORK to create a change in temperature – this is basic thermodynamics!!!!
Jeremy please use the standard equation to state your case. simply (Joel I said simply) Q= U+W.
If W=FD and F = mg then W can be done by heated air rising IF volume changes. We have been told there is a diurnal bulge. As W is a path function and W1-2 (air going up) does not have to equal W2-1 (air coming down) then W could be being done via gravity.
KE and PE in U do not change IF the center of gravity does not change.

202. anna v says:

Bomber_the_Cat :
January 20, 2012 at 3:40 am
In my books an ocean is not a closed system, the way this column of gas is proposed. It is not a good example.

203. Kelvin Vaughan says:

Cosmologists believe in perpetual motion. They believe light travels through the universe ad infinitum without using any energy!

204. Steve Fitzpatrick says:

Good luck in this quest to make those who do not understand begin to understand….don Quixote….. er ….. Willis.

205. Spector says:

For me this is a very simple issue:
1. The Earth is only receiving enough power (or energy flow) from the sun to emit an average of about 240 W/m² from the surface of the Earth. That is derived first, from the solar constant divided by four, the ratio of flat spherical surface area of the Earth to the area of the disk of solar radiation absorbed by the Earth and second, by applying an assumed 30 percent optical reflection factor. Reflected solar energy is treated as never having arrived.
2. According to the Trenberth diagram and the Stefan-Boltzmann equation, the Earth is actually warm enough to be radiating something on the order of 396 W/m² average power from the surface.
3. A transparent, non-greenhouse gas containing atmosphere cannot, by definition, prevent or stop the surface from radiating all this power to outer space. Thus, the surface would be continually losing a net average of 156 W/m² as long as it remained that warm. Fixing this would require a close relative of the perpetual motion machine–the perpetual power creation machine.
4. An average surface power radiation of 396 W/m² can only continue with an atmosphere that can absorb a net 156 W/m² from the outgoing radiated power and return it to the surface.
All technical details of exactly how that happens are irrelevant to this power balance requirement.

206. Steve Fitzpatrick says:

Kevin Vaughan,
No they don’t, light is red shifted if it moves opposite a gravitational field, and blue shifted if moving with the field. The frequency shift shows a change in energy due to the gravitational field. Gravity influences everything, even electromagnetic waves.

207. AJ Abrams says:

Willis, or anyone else.
First, the gravity theory is a non-starter. Willis is correct and people seem to keep missing some very fundamental properties here. Heat is not temperature. Heat is temperature at volume. Keep molecular temperature the same, but increase density and you have more heat. Willis is exactly correct in saying that the upper less dense molecules can have the same temp as the lower more dense molecules and it all be at equilibrium.The PE and KE will vary over height (as related to the gravity point source) so total energy (TE) of any specific given volume of gas can and will come to complete equilibrium over time as the temperature of each given molecule reaches the same temperature. It’s a volume issue. His proof is also correct. If this didn’t happen, you would and could have a perpetual motion issue to deal with. Case close, can we move on to something new please? This doesn’t prove GHG theory correct, it just says the alternative theory is incorrect and people are looking like buffoons. (Engineer by schooling)
I do have a question though. As has been said over and over, our atmosphere volume has to increase if it warms (Total heat). Why are we trying to measure average temperatures, which is meaningless and damn near impossible, instead of not just measuring the height of the atmosphere instead? You would think that an average height of the atmosphere would be much easier to do as a function of time and any trends would then be easy to spot.
AJ

208. AJB says:

Tim Folkerts says @ January 20, 2012 at 6:06 am
Tim, please refer to this page and specifically to the sentence that reads “Ignoring tiny corrections for gravity, the gas will be distributed uniformly in the container, so the only unknown is the velocity distribution function”.

209. Richard M says:

OzWizard says:
January 20, 2012 at 6:43 am
Try to understand it Willis, please. All your thought experiments are irrelevant unless you can demonstrate where their math, or their data, or their ‘grey body’ model, or their regression is wrong. To do that you need to understand what they have done and, by your own admission, you do not yet understand what they have done.

Their math, etc can be completely correct AND Willis can also be correct. All it takes is understanding that the GHE has a maximum value determined by exactly the parameters K&Z use. So, you have a GHE, just as Willis’ thought experiment requires, to warm the surface. You also have many planets that all have reached their own maximum GHE based on atmospheric mass, gravity and irradiance.

210. PeterGeorge says:

“For such machines to work, they’d have to create energy”
I certainly don’t believe in perpetual motion machines, but the above statement is dead wrong. For such machines to work they would have to reduce entropy, not create energy.

211. son of mulder says:

One of my imaginary friend lives on a spherical planet that is not rotating, has an atmosphere consisting of one type of gas and a spherically uniform gravitational field.
There was a time when the planet was uniformly lit from a light source in the surface fed by geothermal energy and some of that geothermal energy uniformly warmed the atmosphere from the surface.
Unfortunately the geothermal fuel ran out and now the planet has no light or heat since.
Before this event my imaginary friend built a tall tower of regularly spaced temperature guages.
They were fortunate that the heat source was not strong enough to cause atmospheric molecules to achieve escape velocity. They found a magic point where the atmosphere reached a maximum height at which the molecules had zero kinetic energy and the temperature read 0 deg K. But the temperature below was none zero because of the geothermal heat source and heat was lost to space through radiation from the atmosphere to maintain equilibrium.
Since the heat source died it has been found that the height at which the molecules of atmosphere have zero velocity is decreasing and the molecules of atmosphere below are cooling.
They have a theory of global cooling that predicts that unless a heat source is found, one day in the future the whole atmosphere will have a uniform temperature of 0 deg K but until then the surface will be warmer than the top of the atmosphere because it is always 0 deg K at the top.

212. anna v says:
January 20, 2012 at 7:24 am
Bomber_the_Cat :
January 20, 2012 at 3:40 am
In my books an ocean is not a closed system, the way this column of gas is proposed. It is not a good example.

Not only that but water is incompressible.

213. Coach Springer says:

From the “lay” sidelines:
I know of a perpetual motion machine: a priori scientific debate. Generates its own energy. Of course that’s debatable.

214. Tim Folkerts says:

AJB says: January 20, 2012 at 7:51 am
“Ignoring tiny corrections for gravity, the gas will be distributed uniformly in the container, so the only unknown is the velocity distribution function”.
I agree completely. If you can ignore gravity, then gases are distributed uniformly in a container. This is a very good approximation for car engines or steam turbines, and so engineers can reasonably ignore the effect of gravity that makes the pressure at the top of a steam vessel 0.0001 atm less than the pressure at the bottom.
However, the thought experiment here specifically removes ALL OTHER EFFECTS BESIDES GRAVITY. Now we are ONLY dealing with those “tiny corrections”. And for a column 10 km high (sort of like the atmosphere), then those gravitational effects become quite important. Density and pressure are known to drop with altitude due to those effect. The question remaining is “does temperature also drop with elevation in a perfectly insulated container?” I say “no”.

215. Tim,
Have a think about why you say no. Then let the rest of us know. And please don’t just throw names around. Describe the physical phenomenon that leads you to the conclusion.
Thanks

216. wayne says:

“Otherwise heat will flow from the hotter (right-shifted MB distribution) to the colder (left-shifted MB distribution) slice until the temperatures are equal.”
Robert, your mistake seems right there in the last statement. The molecule members of the upper hotter right-shifted MB distribution cannot equalize (they are actually already in equilibrium) with the lower cooler left-shifted MB for the acceleration that changes the molecules vertical velocity. I think I am right on that, would you reconsider?
You keep want to say the molecules at various levels must be at the same mean velocity but by your own same example, they can’t in the gravity well case. Maybe the MB derivation doesn’t have a gravitation terms when applied vertically. I’ll stop and check it now.

217. Now, I see where I went wrong. Following the logic of my question to Dr. Brown, I incorrectly thought the final equilibrium arrangement would be where the average energy per molecule was evenly spread out from top to bottom, with the molecules having the same average total energy everywhere. This leads to warmer temperature at the bottom and colder temperature at elevation. Instead, at thermal equilibrium, the average energy per volume is the same from top to bottom, with every cubic metre having the same total energy. To do that, the gas needs to be isothermal, with the same temperature in every part.
Hi Willis,
Permit me to make a small change to this (most of the rest of what I’ve read so far of your post is fine). The final equilibrium arrangement is one where the average kinetic energy per molecule is the same everywhere in the gas column. There are a lot more molecules in the denser gas at the bottom, so there is a lot more internal kinetic energy per unit volume down there, even though the kinetic energy per molecule does not change.
One has to be very careful about how one combines internal kinetic energy and work-based energy. The usual approach is to turn them into the enthalpy of the gas, especially when the gas is in thermal equilibrium with a non-uniform density profile. The usual formula for enthalpy of an ideal gas, E = U + PV, assumes a closed volume, thermal equilibrium, and more or less uniform pressure. Thus one can look at how the enthalpy changes as one e.g. compresses the gas or adds heat. This again becomes complicated when one takes into account variation in density and is the sort of thing that goes into estimating the DALR.
The simplest way to view this is in terms of the heat capacity. The heat capacity of the gas in any volume large enough to hold “many” molecules and be at thermal equilibrium is proportional to the number of molecules in the volume. The gradient in the density that gravity generates in the compressible fluid is accompanied by a gradient in the heat capacity, so that in equilibrium (at the same temperature) the gas at the bottom does have more energy per unit volume than the gas at the top.
The air temperature in the thermosphere can be well over 1000C — in principle hot enough to melt metals. But the atmosphere out there is very thin and the heat capacity is miniscule. The stratosphere — a layer named because of the lack of vertical transport and turbulence — gets warmer from the bottom to the top. That doesn’t necessarily mean that the energy per unit volume increases though, as the density still decreases. It just means that air molecules at the top of the stratosphere are moving, on average, faster than the molecules of air at the top of the troposphere, exactly the opposite of what one would expect from a naive “greater density equals greater temperature” model.
We now return to the regularly scheduled discussion (I haven’t finished reading your post:-).
rgb

218. Hans Jelbring says:

Tim Folkerts says:
January 20, 2012 at 6:06 am
Tallbloke says: “No, as we’ve been saying all along, as have other people on this thread, at the lowest energy state, molecules at the top of the atmosphere have the same total energy as those at the bottom, but less of the total is available as kinetic energy …”
–As has been stated many times in many way, science is not decided by consensus, and science is certainly not by consensus of non-experts. Of the people on this list who seem to have formal training in physics, the agreement seems quite strong that isothermal is the the equilibrium condition for the given thought experiment.
Among OTHER trained physicists I have consulted, that is ALSO the agreement for isothermal rather than a lapse rate.
For instance, they say:
“all of the following are true:
— Boltzmann distribution of kinetic energy
— Boltzmann distribution of potential energy
— Boltzmann distribution of total energy.”
This is in contrast to Tallbloke’s claim that ONLY total energy follows the Boltzmann distribution. —
Hello Tim,
I am just intrigued by your logic. You state about the Tallbloke´s statement: “science is not decided by consensus, and science is certainly not by consensus.” This is absolutely true regarding scientists that are not corrupt or ingorant.
Then you state:
“Among OTHER trained physicists I have consulted, that is ALSO the agreement for isothermal rather than a lapse rate.”
Then you use the consensus argument to “disprove” what Tallbloke claimed.
Do you recognize your fallacy? I am making the comment since you pretend to be scientific.
I can ssure you that I didn´t bother about consensus when I wrote my E&E article. If I had done it would never had been written.
Best Hans Jelbring

219. Steve Richards says:

Why not place a 10metre double insulated tube on a long arm centrifuge, fill tube with dry gas at surface pressure, allow temperatures to settle, the temp should be the same at both ends of the tube.
Rotate centrifuge to give 20g.
We should have multiplied the gravity effect by 20, the short length of tube 10m not 1km, would reduce the effect by 1/1000 so the temperature difference measured should be in the order of 180 millidegrees C assuming 9degrees/Km.
Any temperature difference other than zero would be worth investigating…..

220. Tim Folkerts says:

Tallbloke says:
“Loschmidt, Lagrange, Laplace, Jelbring and me vs Willis, you, Jeremy, Boltzmann and Maxwell
Outside, now!”
Thanks for the laugh. ☺
Let me make one purely semantic argument. The adiabatic lapse rate is ~ 10 K/km. “Adiabatic” means “no energy flow”. So if you can make the approximation that there is little energy flow compared to other energies involved, then the adiabatic lapse rate would be a good estimate of the situation ion the atmosphere. Conduction of heat from one part of the column to another is by definition non-adiabatic. Therefore if conduction is the primary means of energy transport, the situation would not be expected to follow the adiabatic lapse rate.
And that lead me to one slight variation of the though experiment. Consider our perfectly insulated column. I will modify this SLIGHTLY by putting a heat reservoir at the bottom that holds at exactly 300 K (this would be similar Willis’s uniformly lit planet where the SB temperature is 300K at the surface). Now I force the air in the column to be well beyond the adiabatic lapse rate (perhaps I add temporary barriers every 100 m and cool each section by 2 K from the one below ie twice the adiabatic lapse rate). If the barriers are removed, two things will happen.
1) the column of air will be unstable to convection, and the air will start mixing like crazy.
2) there will be heat conduction P/A = k * (Delta_t).
Process 1 will continue until the lapse drops to ~ 10 K/km, at which point it will stop. Process 2 does not need to stop when Process 1 stops. In fact, Process 2 will continue as long as there is any temperature gradient.
NOTE 1: Process 1 will be MUCH quicker than Process 2. I guesstimate Process 1 would be mostly completed within a few hours. But even after convection stops, Process 2 would drive the whole column toward a uniform temperature of 300 K. I guesstimate this would take several months due to the low thermal conductivity of air and the great distances involved.
NOTE 2: If there the air is not perfectly isolated from the rest of the universe causing even a TINY heat sink at the top of the column (even a few mW/m^2), then the rate of conduction will not be enough to erase the lapse rate. GHGs (and even tiny bits of dust) in the upper stratosphere are enough to radiate thousands of mW/m^2 (ie several W/m^2), which means any real atmosphere will have a lapse rate. This tiny leak from the top is enough to maintain the lapse rate, and hence explain why the thickness of the atmosphere plays a major role in surface temperature.

221. Hans Jelbring says:

A physicist says:
January 20, 2012 at 6:18 am
“Here is a Car-Talk Puzzler-type question that (hopefully) will illuminate why Luke and other posters are mistaken.”
“Alice has a cannon that shoots vertically, with a random initial vertical velocity, whose root-mean-square initial value is 100 meters/second, whose mean value is zero, and which is normally distributed (a Bell-shape curve).”
Is there any relevance about your shooting of she is all the time shooting fron the same altititude?
Will she shoot with the same initial root-mean square 100M/s from any altitude?
I am not a physicist so excuse me if misunderstanding you.

222. A physicist says:

Yet another elevator argument for isothermal (same temperature) atmospheric equilibrium is as follows: we imagine a very tall (10 km tall) thermopile column (a device that converts temperature differences to electricity), and we insulate the body thermopile column so that only its top and bottom exchange heat with the atmosphere.
Now supposing that the upper air is colder than the lower air, our thermopile generates electric power continuously and forever, with no external source of power. Which is impossible. And so we conclude that, at equilibrium, the entire atmosphere must be at one temperature.
Of course, in the real world, such a thermopile column would generate electricity. And this electricity would constitute (ultimately) a form of solar power, deriving from sunlight acting to warm the earth, thus creating rising thermals that stir the atmosphere, creating a temperature gradient that the thermopile can exploit.
This is one more line of reasoning showing that the isothermal folks have got the thermodynamics right.

223. Hans Jelbring says:

Tim Folkerts says:
January 20, 2012 at 6:20 am
“You are starting from a wrong hypothesis. My first thought was also that this might be the equilibrium condition, but a bit of actual study of the issue made it clear this is wrong”
If you read my E&E, 2003 carefully you will realize that it is based on two major assumptions and these are:
1) The first law of thermodynamics and
2) Second law of thermodynamics.
The application of these laws in the thought experiments leads to a constant energy content in any two equal submasses of the inclosed insulated atmospherea after relaxation time has passed (approximately 2 weeks).
This was not declared explicitly in the text since it was a topic I wanted to debate but few scientists wanted such a debate. It took 8 eyars for the debate to flourish. Do notice that these laws apply to energy and not temperature.

224. Man_Tran says:

In all the posts I have scanned, with the possible exception of Joe Born, no one seems to be looking at the extreme case of the very top of the air column. Pick an arbitrary altitude where one N2 diatom is occupying one cubic meter of near vacuum (1 km^3?). What is its PE, KE, freq, temperature? Does it just pop off to space? I think that coming from that direction the argument quickly gets to ‘turtles all the way down.’

225. Jim G says:

” For such machines to work, they’d have to create energy, and energy cannot be either created or destroyed, only transformed.”
This is another conventional wisdom based upon the incomplete information available at this time. Where did all the matter and energy that exists today come from? I guess if you buy one of the oscillating universe theories, it has always existed. Or in the multiple universe theories it may have been “transferred” through collision with another universe or leaked into our universe. But it could have been created as well. The how or from where or Whom of the potential “big bang” is as yet not explained by science.

226. pochas says:

Tim Folkerts says:
January 20, 2012 at 8:43 am
“Process 2 [thermal conduction] will continue as long as there is any temperature gradient.”
Well said, Tim

227. “More total energy per molecules times fewer molecules at the top exactly equals less energy per molecule times more molecules at the bottom. Very neat.”

Except that more of the total energy of the molecules at the top is locked up in gravitational potential as opposed to being available as kinetic energy capable of generating heat in collisions.

Except that you meant to say not. Not locked up. How can I put this gently, firmly, and understandably.
How about temperature has nothing to do with gravitational potential energy.
Look, if you want to comment on thermodynamics and temperature, learn what temperature is and what it isn’t.
As far as an ideal gas — the kind considered throughout this discussion, including by Jelbring and N&Z — is concerned, temperature is a direct measure of the average kinetic energy of a molecule of the gas. Note well, I did not say average potential energy and I certainly did not say average total energy or a jar of matter would get hotter or colder every time we lift it or lower it. Here, let me chill my beer by picking it up off of the table and lifting it to my mouth. No.
Please, please, please. Buy an introductory physics textbook that has a halfway decent thermodynamics section. Pretty please with sugar on top. I beg you. Read it.
Look, you have a choice. Either you can pretend that the Laws of Thermodynamics don’t exist and reinvent them at will, making up a brand new definition of the word “temperature” and pretending that your definition will still work to describe things like equilibrium, the flow of heat and entropy, ideal gases, and so on, or you can learn the ones that we already have. Personally, I think your contributions to the discussion would be better if you did the latter, but suit yourself.
Note well, however, that you will not, and should not, be taken seriously if you assert that temperature of a monatomic ideal gas is related to anything but:
U = 3/2 NkT = 1/2 Nm v^2_avg.
or, “the total internal energy of the gas is equal to the number of degrees of freedom times kT per molecule”, for three — note well, three degrees of freedom. Gravitational potential energy is not a degree of freedom, and if it were it still wouldn’t affect equipartition of energy so kinetic energy is a different one.
rgb

228. Hans Jelbring says:

Paolo M. says:
January 20, 2012 at 6:40 am
I am not sure you understand what “potential temperature” actually means. It is a misnomer, at least within the science of meteorology. The meaning is actually constant total energy per mass unit. This state will be be found almost every sunny day above land from the surface up to 1000-4000 m or more. It is best devoloped about 1 hour before sunset. The observational evidence for its existence is just overwhelming.
Another way to put is that at such occations the measured dry adiabatic temperature lapse rate will be very close to -g/Cp or -9.8 K/km (no clouds allowed).

229. Robany says:

I’ve been trying to wrap my head around the thermodynamic arguments for the last few days. The isothermal column of air argument seems to have some problems:
1) The atmosphere has a measurable temperature gradient. An argument that suggests it should be isothermal seems to immediately be falsified by contradiction.
2) Although it’s an equilibrium system overall it is not in thermal equilibrium. We are discussing a system that has a constant energy input (insolation through a transparent atmosphere) at the bottom where the planet’s surface forces a boundary condition on the temperature of the air at sea level. If the planet/atmosphere system is not to heat up then the energy output at the top of atmosphere must match the input. Therefore there must be a flow of energy from the planet’s surface to the TOA and this can only occur if the atmosphere has a temperature gradient and thus is not in thermal equilibrium.
Or have I missed something basic?

230. Tim Folkerts says:

Hans asks me “Do you recognize your fallacy? ”
I recognize your point. But I think it is not quite the fallacy you think it is. I am saying that even a single person who knows what they are doing has applied the principles of known science. He/she has a “proof” (actually several proofs) that the temperature profile must be uniform for the conditions given (and assuming that “textbook thermodynamics” is correct) . That proof has been checked by others to make sure there is no error. This is more akin to “spell-checking” than “consensus”. We now have a new addition to “textbook physics”. (Actually, this is very OLD textbook physics.)
To counter this proof, you need to show a specific error. Maybe there was a sign error. Maybe they took a partial derivative incorrectly. Maybe you can show that a perpetual motion machine IS possible and the 2nd law of thermodynamics IS NOT correct. But if we simply throw back and forth intuition or soundbites, this will not cut it (from either side).
PS This is precisely why “consensus” in climate science is NOT so useful. In the case of the column of air, the situation is very well-defined, so it is easy to apply basic physics and come to a clear solution. For climate science, the situation is very poorly defined. There are sources and sinks of energy all over the place; there are feedbacks; there are continuing subtle changes in orbits, the initial conditions are not well known, etc. All of these mean that you have to include MANY factors in the calculations. This means a computer to determine the predicted affect.
And now there are MANY places for problems. Basically, each person studying climate can only say “I took into account as many of the affects as I could, and here is what I found”. There are (nearly) endless “what if” questions. There are (nearly) endless lines of code to check. This means that there will be considerable uncertainly in the results.
So it is “settled science” that “CO2 radiates IR well and will warm the surface”, because short, easily verified theories (and repeatable experiments) lead inexorably to that conclusion.
It is “settled science” that the air column will be isothermal, because short, easily verified theories (and repeatable experiments) lead inexorably to that conclusion.
It is not “settled science” that “doubling the CO2 levels will cause a 3.7 K increase in temperature” because there are so many other factors and feedbacks that nailing this number down precisely is a damn difficult problem.
PPS Of course, no science is ever 100% “settled”. Relativity showed that newtonian mechanics was not quite right. But overturning “settled science” requires extraordinary evidence. So far I have seen no “extraordinary evidence” that a perpetual motion machine is actually possible and that there could be a continued temperature gradient in a perfectly insulated air column.

231. Hans Jelbring says:

DR says:
January 20, 2012 at 6:58 am
” Does anyone else feel like they’ve been sold a lemon? Even here on WUWT,with the arguing going back and forth, the “theory” is no better explained or proven than it was 25 years ago. ”
No, I don´t feel like that since I have been fighting IPCC and its unscientifc statements since it was created. However, Willis is good at keeping the confusion alive which favours the IPCC organization.

232. Bryan says:

A physicist says:
“Yet another elevator argument for isothermal (same temperature) atmospheric equilibrium is as follows: we imagine a very tall (10 km tall) thermopile column (a device that converts temperature differences to electricity), and we insulate the body thermopile column so that only its top and bottom exchange heat with the atmosphere.”
Have you factored in the resistance of the 10km copper(lets say) leads to your thermopiles?
Once you use real thermopiles and realistic conductors you will realise why this experiment will not work.

233. Final overall comment and off to work.
First, there are actually two kinds of perpetual motion machines that people propose. They are called perpetual motion machines of the first and second kind.
Perpetual motion machines of the first kind violate the first law of thermodynamics. The perform work with no (net) input of energy at all, and thereby increase the mass-energy content of the Universe as they function. They thus violate a very, very basic physical principle as well as a law of thermodynamics.
Perpetual motion machines of second kind violate the second law of thermodynamics. No energy is created or destroyed, it is just moved around so it can be reused again and again.
Both are magic, and actual mythological magic can be classified identically — magic of the first kind is responsible for creating Universes out of nothing, turning lead into gold, and so on. Mass-energy violating magic. Magic of the second kind is more subtle — rising from the dead, healing the sick, walking on water. No energy is created or destroyed, these things are all technically possible, they are just enormously improbable.
Jelbring’s hypothesis enables one to create a perpetual motion machine of the second kind to light stygia. The work done by their Carnot cycle engine and turned into light eventually turns back into heat, so the total energy of Stygia remains unchanged. It is just re-sorted by gravity acting as a Maxwell’s Demon into separated hot and cold reservoirs so that it can be used once again to drive the generator to make more light. The same energy is made available over and over again.
It is this that should make your “horseshit” detectors give a ring. You would have to have been born yesterday to think that Nature gives you any sort of free lunch like that. That hasn’t stopped optimists from seeking PMMs of type 1 or 2, or physicists from proposing theories that violate the laws of thermodynamics, imagining that they are more like “suggestions” than actual laws. But they aren’t suggestions. They are common sense.
* Fact 1: One can run a heat engine between any two reservoirs of energy maintained at different temperatures. Proof: Every heat engine in the world, all of thermodynamic theory, massive engineering…
* Fact 2: Heat engines cannot run indefinitely. In a closed system, they cannot just take random energy in a complex environment and continuously turn it into work. Proof: It’s the second law of thermodynamics Kelvin statement, supported by enormous amounts of evidence and common sense. So much so that if anyone doubts it, I have a bridge that I’d like to sell them in Brooklyn, it should be worth a lot.
* Assertion Gravity sorts air in an adiabatically isolated environment out into hot air at the bottom and cold air at the top. This arrangement is thermodynamically stable and will spontaneously occur and be sustained.
* Argument If the assertion were true, then due to Fact 1, a heat engine placed in the container and run between the top and the bottom would run forever. As fast as it made the air at the top warmer, the heat would somehow “fall” back to the bottom, re-creating the thermal gradient that we know can drive all sorts of heat engines. This violates Fact 2.
* Conclusion The assertion is therefore false. It contradicts two everyday, well-known facts. Anybody who believes Jelbring’s conclusions is invited to make themselves infinitely wealthy, as they have just solved the energy crisis. Just don’t ask me to invest.

234. PeterGeorge says:

“Then the people living in the stygian darkness inside that impervious shell could use that temperature difference to drive a heat engine.”
Wrong. If this argument were correct we wouldn’t need to care about temperature differences. The perpetual motion machine could be driven be the pressure difference alone.
The people would create a massless container to send up and grab some of the low pressure air and bring it down to where the air is is at higher pressure. Then, they could use the pressure difference to drive an engine and do work. Right?
No, of course not. As they bring the massless container of lower pressure (and lower density) air from above it would become a lighter than air balloon. So, it would take work to force it down to the level of the high pressure air. That would negate work done by the pressure difference. No perpetual motion machine.
Couching the argument in terms of temperature doesn’t change the result.
IMhO, there is no way to answer this question about gravity and lapse rates without discussing entropy. Entropy is king. Every other result in thermodynamics – including Boltzman distributions and all the rest, derive from the principle of Equal Apriori Probabilities and the consequence that a system will, in time, inevitably migrate to the macrostate with maximum entropy.
If the isothermal macrostate has higher entropy, that’s where it will go. If a macrostate with a lapse rate has higher entropy, that is where the system will go.

235. Hans Jelbring says:

Spector says:
January 20, 2012 at 7:34 am
“For me this is a very simple issue:
4. An average surface power radiation of 396 W/m² can only continue with an atmosphere that can absorb a net 156 W/m² from the outgoing radiated power and return it to the surface.”
Any surface radiation power exceeding 100 W/m^2 is bull regardless if it is from equatorial, midlatitude or polar regions during days or night. Just show how this fantasy power radiation changes between day and night in polar regions as an exsample.

236. DeWitt Payne says:

Bart,
Your argument begs the question. Your postulate that the atmosphere must decrease in temperature with altitude assumes your conclusion. But it doesn’t have to decrease in temperature. The pressure and the density must decrease with altitude. But a transparent atmosphere is perfectly thermally insulated at the top. It can’t lose energy to space. If the surface is at constant temperature, then eventually, so will be the entire volume.
In the other thread you asked how to define the top of the atmosphere. Here’s a definition: The top of the atmosphere is the altitude which includes 99.9998% of the total mass of the atmosphere. That’s ~100km.
As pointed out above, your first crack at the capacitor example was correct. It’s a constant voltage source. Even a constant current source reverts to a constant voltage source at some voltage.

237. Joel Shore says:

OzWizard says:

N & Z have indeed produced a game-changer here and no thought experiment is needed to understand their ‘Unified Theory of Climate’. Simply stated, their hypothesis consists of their two key equations, (7) and (8).

All they have done is fit some data using a form with many free parameters: There are 4 free parameters in Equation (7) and that is not even including any freedom they may have exercised in choosing the fitting form, choosing how to define T_gb, or even which estimates of the average surface pressure and temperature of various bodies to use.
Hence, it is not surprising that they have fit the data. I got almost as good a fit to the data restricting myself to their particular fitting form when I change 3 of the data points (basically by changing the average temperature of the 3 planets that have a substantial radiative greenhouse effect so that their average temperature is taken to be the conventionally-determined blackbody temperature instead of the observed temperature).
And, that’s another point: Only 3 of the 8 celestial bodies they fit to have a significant radiative greenhouse effect and only for one of them, Venus, is it large enough to be the majority of their calculated surface temperature enhancement. Hence, they are not even fitting data for the greenhouse effect…They are mainly fitting to the effect that a planet can have a number of different average temperatures that are compatible with radiative balance…with airless planets having low average temperatures because of a wide temperature distribution and planets with more atmosphere having higher average temperatures.
One of the strange things about N&Z is how few people have investigated it well enough to even have the most primitive understanding of what they have done!

238. Frank says:

George Turner and WIllis: I’m interested in the idea of turning the tall cylinder of gas, but let’s start with a horizontal cylinder of gas, which should have the same temperature and pressure throughout its length. Let’s say the cylinder is 1 m2 in diameter, contains 10^4 kg of ideal gas (the same weight of gas as above ever m2 of the earth’s surface), and is 20 km/10 mb tall (99% of the atmosphere). Let’s imagine that there are barriers every meter that are closed during rotation and later opened, so we don’t have to worry about what happens during rotation. Alternatively. we can imagine piston barriers that will allow changes to be made reversibly or irreversibly before opening the barriers. What happens when we rotate the cylinder to vertical and open the barriers reversibly or irreversibly?
Based on what we know about our atmosphere, we can be confident that most of the gas will “fall” to the bottom of the cylinder, increasing the kinetic energy/temperature of the gas at the bottom of the cylinder and therefore it’s pressure (ideal gas law). It certainly seems to me that the cylinder MUST be cold on top and hot at the bottom after rotating. If we didn’t just violate the 2LoT by transferring heat by spontaneously creating a temperature gradient where one didn’t exist before (and I assume we didn’t), then we need to be careful about how we describe entropy in this system.
Alternatively, we could say that the gas at the high end expands under reduced pressure and the gas at the lower end is compressed under higher pressure. However, first we need to explain why the pressure on the gas has changed in these regions. We say the weight of the gas above contributed to the pressure on the gas below, but the gas in this cylinder HAD a pressure before it was rotated. Why is pressure in the vertical position defined by the weight of the gas above while pressure in the horizontal position was not? The answer is that pressure is not really created by the weight of the gas above, it arises (according to the kinetic theory of gases) from momentum transferred by collisions (to the walls of a container or whatever is measuring the pressure). We usually assume that motion in all three directions is ISOTROPIC, but in a gravitational field the speed of the molecules moving upward is slightly less that the speed of the molecules moving downward. The “weight of the gas above” appears to transferred downward by non-isotropic motion of the gas molecules in a gravitational field. (See Section 2.3 of your Caballero reference.)
In Brown’s explanation of molecules crossing a plane, he says that the molecules moving up and down :
“have to have exactly the same velocity distribution moving in either direction”
This statement appears to be incorrect. If there weren’t a velocity difference, the pressure at the top and bottom of the atmosphere would be identical. The molecules moving upward have very slightly less energy that the average for their altitude (given the local temperature) and those moving downward have slightly more energy. As they move past each other, they will create a temperature gradient.

239. DeWitt Payne says:

Can we lose the argument that the collision rate, i.e. pressure, has an effect on measured temperature. It doesn’t. A thermometer in contact with a gas at temperature T at low pressure will simply take longer to equilibrate than a thermometer in contact with a gas at the same temperature but higher pressure.
For a gravitationally bound atmosphere at constant temperature, the total energy content per cubic meter decreases exponentially with altitude. The density drops much faster with altitude than the gravitational potential energy increases. See graph here.

240. DeWitt Payne says:

Hans Jellbring,

Any surface radiation power exceeding 100 W/m^2 is bull regardless if it is from equatorial, midlatitude or polar regions during days or night. Just show how this fantasy power radiation changes between day and night in polar regions as an exsample.

Here’s a plot of upwelling IR radiation measured over 24 hours at Desert Rock, NV by a SURFRAD station there. It looks to be more than 100W/m² to me. Note that the time axis is UTC. Desert Rock is -8 hours from UTC so local noon would be 2000 on the time axis.
There are seven SURFRAD stations in the US. You can access the data here.

241. Willis Eschenbach says:

Brent Hargreaves says:
January 20, 2012 at 1:51 am

A recent BBC TV programme on the Earth’s core featured a claim by some scientist that the strength of the planet’s magnetic field has been falling significantly for the past 170 years. If true, might this tie in with the Svensmark hypothesis that changes in cosmic rays hitting the atmosphere affect cloud cover? Might one of WUWT’s resident brainboxes look into this and see if it has legs?

I have considered that. The difficulty is the same as with CO2. In a noisy system like the climate, it’s hard to establish any effect of something which changes extremely slowly.
Regards,
w.

242. Willis Eschenbach says:

Geoff Sherrington says:
January 20, 2012 at 2:05 am

Same answer as I gave early in the “Matter of Gravity” post on January 14, 2012 at 2:45 am

Thanks, Geoff. If you want a comment, please provide a link.
w.

243. Willis Eschenbach says:

John Marshall says:
January 20, 2012 at 2:13 am

Your argument about a heat engine using heat difference not working has been countered by the Norwegians who had a power station off coast in the Atlantic using the heat difference between water layers. It produced 60Mw, until the first severe winter storm when it sunk without trace.

John, here’s the problem. I can’t make sense of this. Who is “you”? Where is their argument about a “heat engine not working”?
Folks, quote or link to what you are talking about. I’m sure it’s crystal clear in John’s head what he is discussing. Out here, not so much. Quote it or link it or forget it.
w.

244. Willis Eschenbach says:

Joe Born says:
January 20, 2012 at 3:46 am

As others have observed above, Willis’s argument has a then-a-miracle-occurs step: he postulates a heat engine that is free of the gravity to which the gas column is subjected. He skipped the the step where Harry Potter removes the gravity from the heat engine’s location.

Not sure what that means, but let’s take a thermocouple … is it subject to gravity? Is it free of gravity? Where did I assume that there was a heat engine free of gravity? What are you talking about? Quote it or link it or it will be ignored.

The mean single-molecule kinetic energy in a system of the type Willis describes is (3E/(5N-2))(1-mgz/E), where N is the number of molecules, E is total system energy, m is molecular mass, g is the acceleration of gravity, and z is altitude. If you put numbers to it, you see that the lapse rate is exceedingly small but non-zero.

If that were true, then we could pull an exceedingly small but non-zero amount of work from it … which would make it a perpetual motion machine.
w.

245. Willis Eschenbach says:

Johan i Kanada says:
January 20, 2012 at 4:09 am

This argument should be possible to resolve in 5 min by any reputable physics professor.
So why not invite one (or several) to comment/clarify?

You’d think so, but we have a couple of reputable physics professors posting in the thread and they are roundly ignored by the perpetual motion crowd. It’s a problem with “gravito-thermal” theorists. To believe that gravity can affect temperature, you have to have a weak grasp of physics, an unshakable belief in your correctness, and a willingness to ignore a bunch of folks who actually understand physics. That’s a bad combo.
w.

246. Willis Eschenbach says:

Alexander Harvey says:
January 20, 2012 at 4:36 am

Hi Willis,
I am pleased that you have retruned to this.
First, something I said on the previous thread was both hasty and in error. …

Alex, I’m sorry but I don’t have time to wander through all of that. My suggestion is to boil it down, then boil it down again, and re-post it.
w.

247. Bryan says:

Willis says
” To believe that gravity can affect temperature, you have to have a weak grasp of physics, an unshakable belief in your correctness, and a willingness to ignore a bunch of folks who actually understand physics. That’s a bad combo.”
Yet only last week Willis believed in an adiabatic distribution for a thermally isolated column of gas in a gravitational field.
This week he has ‘seen the light’.
Don’t be so hard on yourself Willis.

248. Willis,
You contend that no one can explain the Jelbring gravito-thermal hypothesis clearly, which means that no one understand the Jelbring gravito-thermal hypothesis, which is prime facie evidence that it is incorrect. Moreover, you indicate in this post that if the Jelbring gravito-thermal hypothesis were correct, it would contradict the second law of thermodynamics, another good reason for assuming it to be false.
But then you chide Qark for ridiculing the discussion, of something no one can explain.
I can only conclude that you are merely trying to keep the pot boiling for no reason but the fun of it. In which case, I think Qark’s contribution was as worthwhile as most others.
But if that is not the case, I should be glad of your response to this seemingly simple plece of logic, which seems to settle the matter:
At equilibrium, planet-wide outgoing radiation at the top of the atmosphere matches planet-wide incoming radiation at the top of the atmosphere. But if the atmosphere is transparent (i.e., without significant GHGs), outgoing radiation at the top of the atmosphere must be the same as outgoing radiation at the surface of the planet, which means that the mean surface temperature must be the same with or without an atmosphere.
If that is correct, it means that gravity does not account for the greenhouse effect.
If it is incorrect, for the reason Jelbring contends, i.e., that gravity causes an atmospheric temperature gradient that accounts for the greenhouse effect, then planet-wide radiation at the top of the atmosphere must exceed planet-wide incoming radiation, meaning that the planet is luminous. However, we know that the planet is not luminous.
QED

249. SandyInDerby says:

I’m probably joining this discussion too late to add anything useful. To my simple mind there are two things to consider which I have difficulty applying to the atmosphere
First, the diurnal bulge/atmospheric bulge is a bit like a pump which compresses, and as a result heats, the atmosphere and then expands and cools the atmosphere? I assume the heating, however small is greatest at the earth’s surface.
Secondly (as a result of all the references to one molecule at time) I remember when we did a short course on Information Theory http://en.wikipedia.org/wiki/Information_theory we had to work out the theoretical maximum temperature we could heat a teapot to with a fixed amount of boiling water, in order to make a decent cup of tea. http://englishtea.org.uk/how_to_make_tea.html. The maximum temperature is achieved when water is added and removed from the teapot 1 molecule of H2O at a time. As we are dealing thermodynamics, presumably Information Theory is relevant but rarely if ever mentioned

250. Anything is possible says:

Despite being described as a “gravito-thermal theorist”, Nikolov & Zeller seem to have gone to extraordinary lengths to actually mention the word “gravity”. It appears in the text of their Unified Theory of Climate precisely twice.
Gravity, by itself, does not produce heat – surface temperatures on the Moon for example would be identical regardless of whether it’s gravity is one-sixth or six times that experienced on Earth. So to that extent at least Willis, you are entirely correct.
Now consider this thought-exercise :
Introduce an atmosphere equivalent in mass to that of the Earth to the Moon. The vertical structures of those atmospheres would surely be profoundly different according to whether the Moon’s gravitational attraction was one-sixth or six times that of the Earth.
Now consider two “Moons” with identical incoming radiation, identical atmospheric mass and composition, but atmospheres with profoundly different structures due to their differing gravitational attraction.
Identical surface temperatures or not?
Hope that helps……..

251. I skipped most of the comments in this thread, my apologies if this has been said already.
Willis,
You are not going to get the elevator pitch explanation of N&Z that you demand because N&Z relies not on a single paradigm shift, but on several. No elevator pitch can encompass all of them while still articulating a cohesive whole. If you want to understand N&Z, your going to have to allow it to be broken up into pieces, the paradigm shift of each piece understood, and then put the whole thing back together.
I suggest you start with the constant and continuous misaplication of SB Law as it applies to this discussion as I think that is the single major hurdle to get passed. Every thread I see this topic being discussed, I see the same claims. 240 w/m2 = 253K and 288K = 390 w/m2. These numbers are totaly and completely wrong.
SB Law is valid for a very specific case, and that case only. It is valid for a body at equilibrium exposed to uniform radiance and which is at uniform temperature. The earth is NOT exposed to uniform radiance, it is exposed to radiance which ranges from 0 w/m2 to over 1,000 w/m2 and which fluctuates wildly in both space and time. The temperature of the earth as measured is similarly not uniform, it varies in space (latitude, longitude, altitude, time of day, season of year, and orbital variance).
Until we drop the notion that we can arrive at meaningful numbers for earth temperature based upon averages of insolation and temperature compared via SB Law, there is no value whatsoever in discussing the balance of the N&Z hypothesis.
I note in closing Willis that your approach to questioning N&Z has been much more “attack mode” than anything else, and I think that is becoming a stumbling block in terms of having a productive discussion.
dmh

252. Hans Jelbring says:

Robert Brown says:
January 20, 2012 at 9:34 am
Final overall comment and off to work.
“Jelbring’s hypothesis enables one to create a perpetual motion machine of the second kind to light stygia. The work done by their Carnot cycle engine and turned into light eventually turns back into heat, so the total energy of Stygia remains unchanged. It is just re-sorted by gravity acting as a Maxwell’s Demon into separated hot and cold reservoirs so that it can be used once again to drive the generator to make more light. The same energy is made available over and over again.”
Well, if you have read my paper I am not talking about an PM. Willis does so it his problem. I just want to know what is wrong with my paper. For your information an energy generating machin has been constructed to use the energy difference in the oceans. It will of course diminish the temperature difference as time is passing. I don´t see theoretical problem to do the same between the surface temperature and the temperatur at the top of Mount Everest. It is a practical problem of course.
In the case of my model atmosphere there is a temperature difference that can be used for energy extraction. That can only be done by moving energy outside the closed insulated atmosphere. In such a case energy will be removed from the inclosed atmospherea and its average temperature would sink. However such a machine is not allowed since the atmosphere was inclosed and no energy at all was allowed to enter or leave the system. You and Willis seem unable to recognise the assumtions that has been made in the text.
The theory tells that no energy can be extracted within a system that is at maximum entropy and that is also my opinion as long as we stay within the closed system. Willis is favouring a PM and I am not, he has been doing so for 8 years. To avoid more irrelevant comments I want to make clear that ALL content within the closed system consists of ideal gases as is told in the assumptions.

253. An Elevator Speech to prove isothermal result using two tubes of different gases.
The situation we analyze is a uniformly insolated ground in a spherically symetric system with some gravitational gradient. The ground is at a constant temperature T(r=ground). We erect TWO vertical tubes, insulated from the environment and each other, except at two points r=ground, and r=B. We put a different gas (ideal or non-ideal) in each tube. The only difference we require is that they have different specific heat values (Cpx and Cpy). The system must be at equilibrium by definition.
Let us assume that at equilibrium the atmosphere is NOT isothermic, but is a function of r. If so, there must be a real lapse rate in each tube. The Lapse rate (dT/dr) is a function of the Specific Heat of the gas(Cp(i)) and the gravitational accel (g). Both tubes experience the same g, but they have different Cp gasses. Therefore, there must be Difference Equilibrium Lapse rates in the two tubes. At point A, they can have the same temperature, but at point B they must have different temperatures. If they have different temperatures at B, then you can have heat flow at B, which means the system is NOT in Equilibrium. If not isothermal, then not in equillibrium if Cp’s are different.
Only if the gases are isothermal at all z, can the system stay in Equilibrium.

254. mkelly says:

capt. dallas says:
January 20, 2012 at 9:51 am
mkelly said, “Gravity has NO AFFECT ON TEMPERATURE.”
It was actually Jeremy that said “Gravity has no affect (effect) on temperature.” I was asking him to put it in the form of the first law Q=U+W.

255. Tallbloke said:

‘If you are fighting basic ignorance of science, you will be deluged with ignorant people. Not much I can do but just keep putting the facts out there.
Certainly there are a host of much more sophisticated threads, and those tend to attract a more scientifically literate commenter. But when you are discussing “gravito-thermal” theories …’
This is an ad hominem attack which has no place in scientific discourse.

I don’t think so Tallbloke. I have spent the latter half of my 60+ years on Earth discovering that what I “knew” is often enough false. That is, my ignorance has increased. Whenever someone says to me “you are ignorant” I take it as a compliment 🙂
That said, a very great deal of what I know has been well-tested and therefore I currently take to be true. In order to learn, we must continually test what we believe to be true.
Additionally, in order for any significant amount of comments on this thread to be not-ignorant we would have to discard the Law of Contradiction.

256. Embellishment to Rasey 11:09 Two tube example.
Modification 1: Both tubes are optically transparent, but thermally insulated. Fill them with different NON-greenhouse gases, different Specific Heats (Cp). Result must be isothermic.
Modification 2: Now fill one of the tubes with a strong Greenhouse gas. It is optically transparent so it should be absorbing and emitting lots of IR. By the same argument as 11:09, if that tube is not isothermal, then there will be different temperatures at B and non-equilibrium heat flow. So this GHG tube must also be isothermal. But how can it be so if the pressure of the GHG varies with r, and therefore its alleged Greenhouse capacity varies by r. How can it remain isothermal?
(shhh… unless GHG doesn’t matter?)

257. gbaikie says:

“His thought experiment is a planet with an atmosphere. The planet is isolated from the universe by an impervious thermally insulating shell that completely surrounds it, and which prevents any energy exchange with the universe outside. Inside the shell, Jelbring says that gravity makes the upper atmosphere colder and the lower atmosphere warmer. ”
This is true.
But two things.
One it is gravity which causes more density near surface and less density higher- that would be a difference of temperature.
Two: the atmosphere isn’t creating heat. But gravational body can create heat- it will have radioactive elements which create heat and with “an impervious thermally insulating shell”
there isn’t temperature limit, heat keeps building.
I suppose if got rid of all radioactive elements [or only used elements with extremely long half-lives] one would lower the amount of heat generated. I think a pure sample with no radioactive elements wouldn’t be easy to make or find- not sure if or what this could done- or if it would remain so.
Now if you have atmosphere so large it enter the realm of being a planetary type mass, then the atmosphere itself could generate heat. But Earth type atmospheres or Venus type atmospheres are insignificant in regard to planetary masses. Whereas neptune’s mass is mostly “ocean” and “air”- Neptune and other gas giants do have enough atmosphere to have planetary scale atmospheres.
So with this “impervious thermally insulating shell” one could get endless energy from a planet with an atmosphere.

258. Tom Morgan says:

Willis,
With some trepidation I offer this change of your thought experiment…
Assume a long, perfectly insulated tube. One end is anchored on a planet’s surface the other end extends to vacuum ( where it is also perfectly insulated). Assume the tube contains an ideal gas. Assume also that the planet’s surface gravity equal s earth’s (1 g ) and the planet’s radius is also equal to earth’s. No energy is added to the tube, and no energy escapes the confines of the tube. assume the density of the gas is equal to the the density of earth’s air at sea level. Last assumption: Assume the ideal gas is already at vertical (and horizontal) thermal equilibrium.
So the initial conditions are the tube is at the same temp for all altitudes and the density profile is similar to earth’s atmosphere.
Rhetorical question: What happens to the temp as a function of time, and altitude?
Here’s my answer: The temp says constant throughout the length of the tube forever.
here’s how I look at the situation…Consider a plane P at, say, 1Km above the surface (and parallel to the surface) that divides the tube into 2 sections, A and B. The plane does not hinder (or aid) the gas molecules.
In order for the temp to change so that there is higher temp in section A, the average kinetic energy of the molecules in A must somehow increase (that’s the definition of increased temp). However this would be equivalent to Maxwell’s Demon setting up shop at plane P, only allowing fast molecules into A, while only allowing slow molecules into B. Since that cannot happen, the temp in A can not change (also true for B).
I look at this Thought Experiment as your T.E. running backwards in time.
Thanx for all your postings. You are an inspiration.
Tom M.

259. quondam said @ January 20, 2012 at 6:57 am

When one sees the expression “radiative-convective equilibrium” employed, it’s a giveaway that the writer is unconditionally misinformed. There can be radiative-convective steady-states, but any steady-state requires a constant dissipation of either mass or energy for maintenance. That the troposphere might be described as a steady-state implies such an energy of dissipation and, perhaps not too surprisingly, convective stirring takes a steady input ca. 240W/m^2 to be dissipated, but that’s reverting to pre-postnormal science.

Thanks for that insight, Quondam.

260. Bomber_the_Cat says:

Johan i Kanada says:
January 20, 2012 at 4:09 am T
“This argument should be possible to resolve in 5 min by any reputable physics professor.”
Unfortunately, whatever this physics professor said, he would be immediately overwhelmed by lots of commentators here saying that it wasn’t true.
You have now entered the twilight zone, where idiotic comments far outweigh the occasional science that you may come across. The denizens of this zone do not believe in the greenhouse effect, because they don’t want to. They do not understand science (but that doesn’t matter) and so latch on to any passing pseudo- science – as promulgated by various anti-science blogs. As Willis Eschenbach said ” you are fighting basic ignorance of science, you will be deluged with ignorant people”. And in this twilight zone, ignorance swamps knowledge,
Having said that, the problem here is that not easy to solve. There is no empirical test which can resolve it. I think that different physicists could easily arrive at different conclusions based on mind experiments.
From an earlier post:
“The water at the bottom of the ocean is under great pressure. Does this make it warmer? No, we all know that warm water rises. The hotter water is at the top. You can verify that in your bathtub. So pressure does not cause warming. QED.”
Luke says this is because the oceans are heated from the top. But this wouldn’t explain why the water in a domestic hot water tank is hotter at the top. So, good guess Luke, at the obvious wrong answer, but null points.
Tallbloke says that “Not only that but water is incompressible”. The right answer! – have a cigar.
!

261. Robert Brown says:
January 20, 2012 at 9:11 am
Robert, I don’t provide long answers to condescending replies so I’ll just repeat my earlier request:
tallbloke says:
January 19, 2012 at 4:34 pm
Hi Robert,
I think the laws of thermodynamics talk about energy, rather than temperature or heat, but there are several formulations of them, so maybe we’d better discover who is using which definitions. We’d better do this, because in the application of classical mechanics to energy distribution in the model atmosphere, as defined by Hans Jelbring, there will indeed be a thermal gradient, as confirmed by Graeff’s empirical experimental data (Which should be replicated by an accredited laboratory).
And while your checking those out, would you be so kind as to consider my refutation of your ‘slices’ argument:
“if A and B are placed in thermal contact, they will be in mutual thermal equilibrium, specifically no net heat will flow from A to B or B to A.” That’s the zeroth law.
Assuming your A and B have at least some dimension, then a thermal gradient across them would mean that the top surface of A will be at the same temperature as the bottom surface of B where they contact. Therefore no heat will flow. Even so, the average temperature of the whole of body A will be higher than that of B. QED.
Thank you.

262. Crispin in Waterloo says:

I read the contribution by George Turner:
“I take your kilometer’s tall cylinder of atmosphere in thermal equilibrium and flip it over, like flipping an hour glass. It involved no input of work as its height did not change, so the column’s energy remains constant. But now the gas at temp T that was at the top has been wildly compressed, making it much, much hotter, while the gas at temp T that was at the bottom has been expanded, making it much, much colder.”
And Willis’ reply that there is more than half the (mass) of the atmosphere near the bottom. I was thinking as I read George that I would have flipped it at the centre point of mass in which case the objection does not apply. Flip a cylinder of atmosphere that is well above the surface about its centre of mass and allow it to float vertically (as it wll tend to do). The mass remains the same, the centre of mass will remain the same distance above the surface at all times even if the (‘mechanical’) flipping point rises or falls, the flipping requires no energy. The same compression and decompression mentioned by George applies and there will not longer be an isothermal state. Having now perturbed the initial isothermic condition, it will not re-establish itself even if perfectly insulated.
Why? As the atmosphere is not a solid, gas molecules will move up and down randomly. As a parcel of molecules rises the temperature will drop due to expansion. Yes, the potential energy with respect to the surface rises, but the temperature drops and this is about temperature which is a measure of only one type of energy. The thesis states that there will be a difference in temperature, top and bottom, it does not make claims about a difference in total energy with respect to the surface of a gravitational object. Work accomplished heating a falling molecule has to be accounted for by cooling taking place elsewhere in the system. It cannot come from the bottom of the system.
One can make an argument that the total energy in any molecule is constant at all heights but I doubt that applies to any molecule in a spherical atmosphere. If it applies to a particular sphere (because of a perfect balance between sperical expansion and elevation) it cannot also apply to a ‘flat planet’ with a cylinderical sample of atmosphere because the volumeetric expansion rate is different (trumpet v.s. clyinder). Because it cannot be correct for both, I suspect it is generally correct for neither save in special cases.
From an initial isothemal state all molecules falling will warm and all molecules rising will cool. The heat will accumulate at the bottom. There is no work done. Gravity does not do any work. The heat will shift towards the bottom because gases move without input of energy and cool or heat adibatically.
The idea of using the temperature difference between the hot and cold zones to generate power is a good one. It will work, but will cool the whole atmosphere in the process. It was written above as if all the heat from below would be vented near the top of the atmosphere, therefore that would allow the heat to migrate down again and this be recycled, but this description is incomplete. Energy extracted in the form of energy would be subtracted from the heat processed, providing net cooling by exactly the amount of the energy extracted (including friction). So it would work for a while, converting the atmosphere’s heat into electrical or mechanical energy. It is exactly the same as using the temperature differential between the surface and the ocean deeps to generate electricity. It works (quite well) but it cools the ocean in the process and it is not perpetual.
In the Elevator:
1. Gas molecules move about with no external input of energy. Therefore they may rise or fall in the atmosphere over time.
2. It is well established that gases cool when decompressed and heat when they are compressed. In a free atmosphere above a spherical, insulated planet, molecules are free to compress and decompress as they move vertically. There is no work performed during this process because they are drifting in free space. The total heat content of the system remains constant.
3. If an atmosphere was initially isothermal, the higher elevation gases would have to have been artficially heated to be at the same temperature while also being in a decompressed state. The lower gases would have to have been artificially cooled to be as the same temperature and simultaneously in a compressed state.
4. As the gases move randomly about the vertical column, the hot molecules dropping from above will carry heat downwards, increasing in temperature above the initial average. Lower gases rising will cool by adiabatic expansion below the initial average. There is no net heating or cooling in the atmosphere.
5. After a time, when equlibrium is established (no net change in temperature of any horizontal slice of the atmosphere) it will be warmer at the bottom and colder at the top. The direct cause for this temperature difference is gravity and the effect is observed because of the size of the system (large) and the lack of any external, gravitational perturbations.
6. If gravity is increased, or if the total volume of atmosphere is increased, the equilibrium temperature at the bottom will increase. An average temperature can be calculated, as can an elevation at which this temperature will be observed.

263. Ged says:

Very interesting discussion Willis, and nicely done.
The only thing that gets me is the idea that the gas would be isothermal (temperature being kinetic energy) violates the conservation of energy. As a gas molecule moves away from the gravity source, it MUST lose kinetic energy to potential energy. As it falls back down, it’ll convert that potential energy back to kinetic energy. Ergo, energy is conserved. But -temperature- is the observation of kinetic energy, not potential energy.
In that regard, a higher elevation must be cooler in -temperature-, even if the heat content (total energy) is the same. I think that’s the problem. We conflate temperature with heat, when they are not the same thing.
You can have two objects at different temperature, but if they are equal in heat, so that energy cannot transfer one way or the other, this temperature difference must be maintained. And we can do this by turning kinetic energy (temperature) into potential energy. No heat is lost.
I’m not defending the gravity thermal theories, but I am expressing how I cannot understand this thought experiment in terms of energy conservation. And I wonder if the ideas about heat and temperature have gotten crossed. Or maybe I am fundamentally misunderstanding?
But still, raising up means losing kinetic energy to potential energy, and temperature is kinetic energy not potential energy. Heat transfer can only happen through kinetic energy, not potential energy… So to conserve energy, temperature must decline while raising above a gravity source… Likewise, if you stand in a gas close to the gravity source you’ll get hit by more collisions than if you sit above where more energy is locked in potential energy. And, if you used your body’s temperature (kinetic energy) to push you upwards against gravity, you’d cool your body down as more energy was put into potential, right? You’d still have the same amount of energy in you, but you’ve transformed it. That’s the only logical conclusion I can come to. Isothermal (temperature wise) while moving in a gravity well doesn’t make sense to me at all, and nor do we ever see that in nature in atmospheres.. to my knowledge.
Again, maybe I am missing something.

264. Marc77 says:

I have to disagree here. It is possible to make energy between the ground and the top of the atmosphere because the ground is warmer than space from the point of view of the atmosphere. The atmosphere does not see the Sun because it does not absorb in the UVs. So space is very cold for it. If there was a blob of nitrogen in orbit around the Earth, it would be cold. So it would be possible to make energy between this blob of gas and the ground. Don’t forget, the ground is warmer than space in the IR.
Think about a one molecule atmosphere. It receives or gives energy to the ground every time it hits it. The vertical kinetic energy of the molecule near of the ground can be different every time. But each time, it slows down as it goes up and then it speeds up when it comes back down. If you make an average over multiple hits to the ground, you will find these 2 facts:
1- It is more often near of the ground(higher pressure at the ground level).
2- It has more kinetic energy near of the ground(Higher temperature at the ground level).
If you increase the number of molecules, each of them will still lose kinetic energy as it goes up.
Now, let’s make a little thought experiment. Let’s imagine an invisible layer around the Earth at a certain altitude. The number of molecules passing from under to over the layer has to be the same as the number of molecules going the other way at equilibrium. The amount of kinetic energy also has to be the same at equilibrium. Now let’s put a second layer very near of the first to look at the derivative. What’s been said in the first part of this paragraph still holds true. But sometimes, a molecule will pass through the lower layer and come to vertical halt between the layers and it will go back down through the lower layer without passing the higher layer. This is where the differential of pressure appears. Every time a molecule passes through both layers, it either loses kinetic energy on its way up or gain kinetic energy on its way down. If 2 molecules hit each other, you have to look at the pair of molecules. The center of mass can turn around between the two layers, pass the two layers in an upward or downward motion. And the pair of molecules will act like a single molecules if you calculate the differential of pressure or the differential of kinetic energy between those two layers.

265. jorgekafkazar says:

John Marshall says: “I also ask my Jupiter question again. Why does this gas giant radiate more heat than it receives from the sun. your argument above makes this impossible.
My astrophysics instructor said he believed there were decaying fissionables at the core.

266. Hans Jelbring says:

Stephen Rasey says:
January 20, 2012 at 11:09 am
“An Elevator Speech to prove isothermal result using two tubes of different gases.
Let us assume that at equilibrium the atmosphere is NOT isothermic, but is a function of r. If so, there must be a real lapse rate in each tube. The Lapse rate (dT/dr) is a function of the Specific Heat of the gas(Cp(i)) and the gravitational accel (g). . If they have different temperatures at B, then you can have heat flow at B, which means the system is NOT in Equilibrium. If not isothermal, then not in equillibrium if Cp’s are different.
Only if the gases are isothermal at all z, can the system stay in Equilibrium.”
I certainly don´t believe that an elevator speach is the way to perform scientific work.
You are free to express your opinion whatever it is but in this case it is not based in scientific reasoning and definitly not based on first principle physics.
The adiabatic temperature lapse rates that will develope (if long time enought will pass) in your examples are given by dT/dZ = -g/Cp1 and the other will be given by dT/dz= -g/Cp2. A remarkable fact is that both these laps rates are independant of the absolute amount of energy that was inclosed in each tube. In both cases the energy in two arbitrarily chosen equal mass units will carry the same amount of energy. Remember that the 1:st a and 2:nd law of thermodynamics apply to energy, not to temperature. When gravity is not included the second law can be formulated in terms of temperature even if it is not recommended (but very common in anglo litterature).

267. Joel Shore says:

davidmhoffer says:

I suggest you start with the constant and continuous misaplication of SB Law as it applies to this discussion as I think that is the single major hurdle to get passed. Every thread I see this topic being discussed, I see the same claims. 240 w/m2 = 253K and 288K = 390 w/m2. These numbers are totaly and completely wrong.

No…They are not “totally and completely wrong”. The 288 K = 390 W/m^2 is in fact quite accurate for the Earth’s present temperature distribution to a good approximation (introducing about 2K of error with a generous estimate).
The 240 W/m^2 = 255 K is a bit dicier since it is for a hypothetical world that is a little hard to specify and could have a somewhat broader temperature distribution. However, what can be said rigorously is that a blackbody radiating an average of 240 W/m^2 could have an average temperature no higher than 255 K. It could have an average temperature lower than that (which is what N&Z show with their T_sb calculation that assumes an extremely broad temperature distribution since the local instantaneous temperature is determined by radiative balance with the local instantaneous solar insolation). [To the extent that the Earth is not exactly a blackbody in the mid- and far-infrared, the average temperature could be higher, but for the terrestrial surface, we are talking about 3 K at about the outside limit. And, the fact that the “non-uniform effect” and the “not exactly a blackbody effect” go in opposite directions means the two effects tend to offset each other to some degree.]
By the way, for those who want a more precise quantification, I have derived a formula for the difference between the fourth root of the average of T^4 and the direct average of T. The formula is that this difference is given by
difference = (3/2)*(sigma^2)/T_ave
where sigma is the standard deviation of the distribution of T and T_ave is the average value for the distribution (in absolute temperature units, like Kelvin). [Although this formula is an expansion good for small sigma/T_ave, I have verified that it gives answers within 2% of the actual difference for two distributions (Gaussian and flat “box” distributions) for sigma/T_ave < 0.10 (which is larger than any reasonable estimate I can make of the relevant value for Earth).]
Dave, we all know that you have become completely obsessed with this particular issue…but you have failed to refute both my and Willis's rough quantifications of its magnitude and hence you are continuing to "make a mountain out of a molehill" on this subject.

268. ShrNfr says onJanuary 19, 2012 at 4:03 pm :
“However, we do have a real heat source in the earth’s core with the fission of heavy nuclei. Not perhaps a lot, but some. I never have gotten any really good estimates of how large the effect is, and I am not enough of a geologist to derive it. Anyone around have an idea??”
===
If it can help – my advice to you – is to go back in history and look up where it all originates and how “Global Warmists” or “CAGW” alarmists get it wrong, even right from the start, with written history.
The 18th and 19th Centuries saw many famous Philosophers/researchers. (They did not all live long enough to be called Scientists – as that title is fairly new)
Let me quote, if I may, Timothy Casey B.Sc. (Hons): Consulting Geologist who has put the papers of some of them online: “According to Weart (2003, Flannery (2005) and Archer (2009) the “Greenhouse Effect” originates with Fourier, ——.” – And further on: “Arrhenius claimed:
Fourier maintained that the atmosphere acts like the glass of a hothouse, because it lets through the light rays of the sun but retains the dark rays from the ground.”
Nothing could be more wrong – or further from the truth – Put “Fourier (1824) as translated by Burgess (1837)” into your “Computer search engine” or http://geologist-1011.net and see what comes up. You will learn a lot – including, maybe, why davidmhoffer says what he says on January 20, 2012 at 10:49 am.
Reading Fourier’s paper from 1824 really is worth the effort and Timothy Casey B.Sc is a pretty good teacher too.
O H D

269. Ged says:

Oh, I think I should also point out that I was ignoring radiative transfer for heat, since that isn’t part of the thought experiment. But that necessarily energy is lost to space as radiation which cools everything over time, and without energy input, there will be no energy to propel gas molecules up against gravity. So then, after a certain amount of time, the entire atmosphere will settle down upon the surface with no more “bouncing” molecules jumping around.
But since the sun warms our surface, it acts to “bounce” molecules upwards, where they bounce against each other, etc, and act as a kinetic battery for storing energy. But again, as a ball, or molecule, bounces upwards, it loses energy and slows down (temperature decrease if temperature is the only thing driving this as it is in the atmosphere of our thought experiment), then plummets and warms back up, bounces again, and so forth. It’s just like watching balls bounce around a vibrator machine.
So… it seems to be you will have a thermal gradient, no matter what! It’s just will this gradient make apparent temperatures in the atmosphere at the surface higher than the S-B surface temperature?
Again, not defending these gravity-thermal theorems, but I do fully believe that gravity creates and maintains a thermal gradient for altitude above the surface (this also ignores the increasing volume of the sphere as we raise above the surface which decreases temperature and/or pressure).
I dunno, those are my thoughts, Willis. I actually think Dr. Brown was wrong then.
And could you generate energy from the atmosphere using a thermocoupler? Of course! But it would be ENORMOUS to have to reach high enough from the surface up to altitudes where the temperature drops (30,000 feet is pretty dang cold 😉 ).

270. Bryan says:

Stephen Rasey good post.
For your first proposed experiment if you use argon and hydrogen you should get about 2K difference in 100m tubes which should be reasonably practical and measurable.
I like even better your second proposed experiment.
….” But how can it be so if the pressure of the GHG varies with r, and therefore its alleged Greenhouse capacity varies by r. How can it remain isothermal?
(shhh… unless GHG doesn’t matter?)”…..
Just goes to show that for isothermal/adiabatic distribution nothing can save the greenhouse effect.

271. TRM says:

I’ve always loved the ingenuity of those who tried and in some cases succeeded”
http://en.wikipedia.org/wiki/Beverly_Clock
A six-degree Celsius temperature variation over the course of each day creates enough pressure to raise a one-pound weight by one inch (energy extracted = .11 joules), which drives the clock mechanism.
Just ignore the next line in the description that says “It is not therefore an example of perpetual motion.”. Okay it is “naturally assisted” perpetual motion but still a darned impressive piece of work providing real output.
There were earlier clocks as well that used this principle.

272. Joe Born says:

Willis Eschenbach: “Where did I assume that there was a heat engine free of gravity?”
I believe you did so without realizing it. But perhaps a better way to express my meaning would have been to say that you have begged the question by assuming a heat engine could be designed that could perform work operating between the differences in altitude and temperature that Velasco et al.’s lapse rate specifies.
My contention, which I at least for the moment believe Velasco and his colleagues have established through a statistical-mechanics-based proof, is that the maximum-entropy configuration of the system you describe exhibits a small but non-zero temperature lapse rate. If that is true, then isn’t it true that a heat engine operating between the same differences in altitude and temperature would have to reduce entropy to operate? If not, then perhaps you could reveal the heat-engine design you have in mind. Otherwise, you’ve just allowed invocation of the term “heat engine” to short-circuit further analysis.
I have to confess that two weeks ago I was arguing over at tallbloke’s place for the same position you’re taking now: http://tallbloke.wordpress.com/2012/01/01/hans-jelbring-the-greenhouse-effect-as-a-function-of-atmospheric-mass/#comment-12926. Currently I think I was wrong then and that you’re wrong now. Maybe by tomorrow you and Dr. Brown will have convinced me otherwise.

273. DeWitt Payne says:

Bart,
Your solution of the heat equation in spherical coordinates ( ∂T/∂t = αΔT ) is wrong. As you point out above, α is not a constant with r. α is the thermal diffusivity = thermal conductivity, k (which is a constant), divided by the product of the density, ρ, and the heat capacity at constant pressure, Cp = k/(ρCp). But density decreases exponentially with altitude so the diffusivity increases exponentially with altitude. That means the heat equation must be derived again with this condition and solved. According to the Wikipedia page on the heat equation

In the anisotropic case where the coefficient matrix A is not scalar (i.e., if it depends on x), then an explicit formula for the solution of the heat equation can seldom be written down.

Then you say:

So, the conclusion remains: there is always a thermal gradient pushing heat continuously into the atmosphere, and it will not stop until either there is some kind of radiative release, or the atmosphere flees.

You can’t have it both ways. You have a logical contradiction. You say the temperature must always decrease with altitude but then you say the temperature increases at altitude basically without limit. You also can’t wave your hands and say the surface temperature also increases without limit because it’s warmed by the atmosphere. It can’t be by your condition that the temperature gradient is always negative (positive lapse rate). So what you’re actually saying is that the surface temperature increases without limit. But that can only happen if the emissivity of the surface is zero, or at least very small. But of course, it isn’t. In Willis’ example, it’s defined as equal to 1. You can also assert all you want about the SB equation not applying, but you have given no evidence or citation that it doesn’t. Even if the emissivity does vary with wavelength and angle, one can still integrate the Planck equation, B(λ,T) and get the total emission. The SB equation will still be a very good approximation for most real materials.
Oh, and molecules at high altitude are not in orbit even if they are moving at the same radial velocity as the surface below them. The correct reference frame for determining the RMS velocity is a rotating spherical coordinate system with the rotation rate equal to the rotation rate of the planet. A molecule that was actually in orbit would indeed have very high kinetic energy relative to the molecules around it. If that were not the case, then satellites in low orbit would not be subject to atmospheric drag.

274. Willis Eschenbach says:

Bryan says:
January 20, 2012 at 10:24 am

Willis says

” To believe that gravity can affect temperature, you have to have a weak grasp of physics, an unshakable belief in your correctness, and a willingness to ignore a bunch of folks who actually understand physics. That’s a bad combo.”

Yet only last week Willis believed in an adiabatic distribution for a thermally isolated column of gas in a gravitational field.
This week he has ‘seen the light’.
Don’t be so hard on yourself Willis.

Since I obviously don’t have an unshakeable belief in my correctness (I publicly admitted I was wrong), and since I obviously listened to the ideas of Robert Brown, who actually understands physics, I fear your reading skills appear to be in desperate need of improvement …
w.
PS—This week, I learned something. I expanded my understanding of physics. You can disparage that all you want, by calling it “seeing the light”, but to me, learning is invaluable gold, and your childish sneers can’t tarnish it. You ought to try it yourself, Bryan, you might like it.

275. Willis Eschenbach says:

CanSpeccy says:
January 20, 2012 at 10:27 am

Willis,
You contend that no one can explain the Jelbring gravito-thermal hypothesis clearly, which means that no one understand the Jelbring gravito-thermal hypothesis, which is prime facie evidence that it is incorrect.

Quote my words, you are off in fantasy. I gave a “elevator speech” laying out the Jelbring hypothesis, which demonstrates that I understand it even if you don’t.
In addition I have never argued that it must be incorrect if no one understands it.
QUOTE MY WORDS that you disagree with, CanSpeccy, I haven’t a clue what your are talking about.
w.

276. jorgekafkazar says:
January 20, 2012 at 12:02 pm
John Marshall says: “I also ask my Jupiter question again. Why does this gas giant radiate more heat than it receives from the sun. your argument above makes this impossible.
My astrophysics instructor said he believed there were decaying fissionables at the core.

Was he waving his arms in a wiggle matching sort of way when he said it? 😉

277. Willis Eschenbach says:

davidmhoffer says:
January 20, 2012 at 10:49 am

I skipped most of the comments in this thread, my apologies if this has been said already.
Willis,
You are not going to get the elevator pitch explanation of N&Z that you demand because N&Z relies not on a single paradigm shift, but on several. No elevator pitch can encompass all of them while still articulating a cohesive whole. If you want to understand N&Z, your going to have to allow it to be broken up into pieces, the paradigm shift of each piece understood, and then put the whole thing back together.

You can believe that if it helps you to sleep. Me, I’m still waiting for someone to give a clear explanation of N&Z. Your claim, that it cannot be explained simply because its all too complex, just tells me that you don’t understand it.
But heck, let’s play it your way. You say you can do it if we break it up into pieces. OK, give me the elevator speech for the first piece of the lot, we’ll start with that.
w.

278. mkelly says:

Willis says: “Thanks, Jeremy. You are a hundred percent correct, gravity can’t do ongoing work to change the temperature.”
Gravity does not do work it causes work to be done.
Q= U + W (first law)
W=FD
F=ma
a=g (g is gravity)
W=mgD
W=PdV
This is stated simply on purpose.
It is the gas that is doing the work against the force of gravity else why would a heated column of air stop rising. What the magnitude or if it is? Or is it offset somewhere else is a different story.

279. Phil. says:

Bart says:
January 19, 2012 at 11:06 pm
Look at the earlier thread. I’ve got it nailed. There is no doubt about it.

Such hubris, actually you’ve got it wrong, but refuse to acknowledge it.
Your explanation contains a basic thermodynamic error as shown below (again).
F) the transferred heat accumulates in the atmosphere until:
1) highly energetic emissions are stimulated, which balances the energy fluxes all around in the same way GHGs would in the standard “greenhouse” theory
OR
2) the heat accumulates until the atmosphere achieves escape velocity and vanishes.

This is where you introduce the fundamental error in your analysis.
What it should say is that ‘the heat accumulates in the atmosphere until the layer of gas nearest the surface reaches the surface temperature at which point heat transfer ceases due to ΔT=0.’ There can be no more heat transfer to the atmosphere unless it cools down and ΔT again exceeds 0. This is the fundamental flaw in all the ‘hotter and hotter’ arguments (it’s independent of the profile with altitude).

280. Willis Eschenbach says:

Hans Jelbring says:
January 20, 2012 at 12:15 pm

… I certainly don´t believe that an elevator speach is the way to perform scientific work.
You are free to express your opinion whatever it is but in this case it is not based in scientific reasoning and definitly not based on first principle physics.

Hans, like you I “don´t believe that an elevator speech is the way to perform scientific work.” So we are in agreement on that.
What it is useful for, as I have said before, is three things:
1. It helps me to clarify my own thoughts. When I only have a few sentences I am forced to be clear.
2. It helps me to explain ideas to other people.
3. It helps me to determine if someone else understands something, under the principle that if you can’t explain it clearly, you don’t understand it clearly.
You have claimed in the past that no “elevator speech” for your theory could be any shorter than your original paper. And indeed your paper is concise … but a much simpler explanation could be given.
I have given my simple explanation, my elevator speech for your hypothesis, in my head post. If you think any of the statements is wrong, please let me know a) which one is wrong, and b) what’s wrong with it. If you think a logical step is missing, please provide it. Blanket statements and denunciations will not serve in this case, please avoid them.
My best regards, Hans,
w.

281. rwemyss says:

@Hans Willis is NOT indicating the heat engine will REMOVE energy from the system! He is indicating that the temperature difference used to run the heat engine can do work on the fluid in the system, and infinitely do so per the theory. Hence the theory fails.

282. DeWitt Payne says:

Bart,
I’ve calculated the thermal diffusivity, α, of air as a function of altitude at a temperature of 255 K.
km α(m²/s)
0 1.65E-05
10 6.30E-05
20 2.39E-04
50 1.28E-02
100 8.91
For reference, the thermal diffusivity of pure silver is 1.66E-04m²/s. You can see why the IPCC allows the stratosphere to equilibrate before calculating forcing. The equilibration time is going to be short.
If I’m really bored sometime, I’ll try to calculate numerically the temperature profiles for a gravitationally bound vertical column of atmosphere 100 km high with an initial temperature of 2.7 K for a monatomic, non-condensable ideal gas with a heat flux into the surface of 240 W/m² and a surface emissivity of 1.

283. Werner Brozek says:
January 19, 2012 at 7:30 pm

If the sun heats the surface and outer space is cold

That’s the problem – outer space has no temperature. Temperature has meaning for substances (stuff), not for a vacuum. The only way to transfer heat to space is via radiation, and the only way for the atmosphere to loose heat to space is to have greenhouse gases that radiate energy.

284. Willis Eschenbach says:

Hans Jelbring says:
January 20, 2012 at 11:03 am

Robert Brown says:
January 20, 2012 at 9:34 am
Final overall comment and off to work.

“Jelbring’s hypothesis enables one to create a perpetual motion machine of the second kind to light stygia. The work done by their Carnot cycle engine and turned into light eventually turns back into heat, so the total energy of Stygia remains unchanged. It is just re-sorted by gravity acting as a Maxwell’s Demon into separated hot and cold reservoirs so that it can be used once again to drive the generator to make more light. The same energy is made available over and over again.”

Well, if you have read my paper I am not talking about an PM. Willis does so it his problem.

And therein lies the problem, that you’re talking about perpetual motion and you don’t know it. Hans, you are indeed proposing perpetual motion. You are saying that gravity separates the warm and cold molecules.
If that were true, we could use the temperature difference to perform work forever in your thought experiment world which is sealed off so no energy comes in or out. How is that possible?
Either you need to:
a) show that there is no problem with a sealed system performing continuous work with no energy inputs or exchange with the outside world, or
b) show that for unknown reasons, we could not use the temperature difference to perform work.
I see no reason that we could not extract work from your claimed temperature difference, we’ve been doing that for hundreds of years. So if gravity creates a temperature difference, the default assumption has to be that we can extract work from that temperature difference.
But if so, you could get unceasing work out of gravity forever … and while that would be a nice trick, no one has ever done it, there is no physical theory saying it is possible, and the laws of thermodynamics say it won’t work.
That’s why we call it a “perpetual motion machine”. If you think not, then you will have to do either a) or b) above. I see no way to do either.
In fact, your thought experiment is an excellent one to show that gravity can’t possibly affect the temperature of an atmosphere such as you postulate. If it could, you could use the gravity-created temperature difference to light Stygia forever, and you’d be a hero for solving the energy crisis, we could just run the world off of gravity …
Thanks,
w.

285. Joel Shore says:

Willis Eschenbach says (in response to davidmhoffer):

But heck, let’s play it your way. You say you can do it if we break it up into pieces. OK, give me the elevator speech for the first piece of the lot, we’ll start with that.

Oh…This sounds like fun! I volunteer to give the elevator speech for Section 2.1)B:
“In Section 2.1)B, N&Z demonstrate that when you add convection to a simple radiative model of the greenhouse effect in such a way that it drives the atmosphere to an isothermal temperature distribution with height, then you no longer have a greenhouse effect. Unfortunately, however, in the real atmosphere, convection only drives the atmospheric distribution as far as the (appropriate) adiabatic lapse rate and the greenhouse effect does not disappear. That the temperature at the ‘effective radiating level’ must be colder than the temperature at the surface in order to have a greenhouse effect was already well-known.”

286. O H Dahlsveen says:
January 20, 2012 at 12:16 pm
Let me quote, if I may, Timothy Casey B.Sc. (Hons): Consulting Geologist who has put the papers of some of them online: “According to Weart (2003, Flannery (2005) and Archer (2009) the “Greenhouse Effect” originates with Fourier, ——.” – And further on: “Arrhenius claimed:
Fourier maintained that the atmosphere acts like the glass of a hothouse, because it lets through the light rays of the sun but retains the dark rays from the ground.”
Nothing could be more wrong – or further from the truth – Put “Fourier (1824) as translated by Burgess (1837)” into your “Computer search engine” or http://geologist-1011.net and see what comes up.

Class. I’ve reposted the Fourier translation, thanks muchly.
“It is equally probable, that in respect to most of the planets, the temperature of the poles is little above that of the surrounding space, with respect to the temperature which each of these bodies owes to the sun, it is not known; because it may depend on the pressure of an atmosphere and the condition of the surface.”

287. Trick says:

Geez, folks here move around more than ideal gas molecules > 0K. Including me.
Willis says 1/20 10:49am: “Me, I’m still waiting for someone to give a clear explanation of N&Z.”
Robert Brown says 1/20 9:34am:
*” Fact 1: One can run a heat engine between any two reservoirs of energy maintained at different temperatures. Proof: Every heat engine in the world, all of thermodynamic theory, massive engineering…
Fact 2: Heat engines cannot run indefinitely. In a closed system they cannot just take random energy in a complex environment and continuously turn it into work….
* Assertion Gravity sorts air in an adiabatically isolated environment out into hot air at the bottom and cold air at the top. This arrangement is thermodynamically stable and will spontaneously occur and be sustained.
* Argument If the assertion were true, then due to Fact 1, a heat engine placed in the container and run between the top and the bottom would run forever. As fast as it made the air at the top warmer, the heat would somehow “fall” back to the bottom, re-creating the thermal gradient that we know can drive all sorts of heat engines. This violates Fact 2.”
Trick says “No, this heat engine won’t run forever”. My view: the N&Z assertion IS true since it can be shown to comply with natural laws. Can Willis’ find a fail? Here’s my view:
As Robert Brown writes, the air container in question is an isolated closed system so by Robert’s Fact 2, that heat engine cannot run indefinitely & thus it will run to control volume (cv) equilibrium and stop. The heat can’t “fall” once in equilibrium. There is no way to perpetually “maintain” the non-equilibrium unless the heat reservoirs are infinite & they are not. Eventually, in the same control volume, every real hot & cold irreversible heat engine equilibrates the two non-infinite hot & cold “fuel” reservoirs and stops making work – up until the reservoirs are “maintained” i.e. replenished across the cv. Like my refrig. with the electricity off. Gotta’ plug it in.
In the N&Z thought experiment case at hand viz. a tall adiabatic (occurring without gain or loss of heat across cv) control volume of GHG-free air i.e. gas in the presence of gravity will reach equilibrium and the heat engine will stop. No way can it be made to run except by being an outlaw. This occurs in the non-outlaw earth & near earth planets.
There are at least three important laws applicable to understand the tall air column cv of height h in the presence of gravity, there may be more, but each of these must ideally operate at same time & are sufficient to arrive at equilibrium in the cv of interest & some conclusions:
1st law: conduction always operates from high T to low T objects made of normal matter & they touch, to equilibrium.
2nd law: energy is always conserved & usually written PE + KE = constant (here P*V = KE, ngh = PE).
3rd: ideal gas law: PV = nRT (where in the cv of interest we hold V, n, and of course R constant)
So here’s what the 3 natural laws together mean will happen at equilibrium in the cv: the inexplicable gravity field will drive the tall column of gas to stratify itself with higher pressure at the bottom (2nd law: P*V + 0 = const. at h=0) due to the “weight” of the gas above (ngh). This is sustainable in adiabatic cv.
At column top, there must be lower pressure written by 2nd law also: P*V + ngh = same const. P*V is thus lower and with V constant, it is pressure P that has to be lower. No way around it, fight the laws all you want (I know y’all will try).
That means if you put a thermometer at h>0, it will show temp. T at h>0 . Put the same thermometer at bottom (h=0) read: T + delta T. The delta T from increased KE which has to be larger since V is constant to get (P*V + 0) = same const. = (P (at h>0) * V + ngh). Try that with P0 and Ph subscripts for practice. You can do it Willis.
The temperature (KE) of the atmosphere reduces as h (really ngh PE) increases above 0 for earth & nearby planets. N&Z stands. AND with all three laws operating from top to bottom, we’ve achieved closed system equilibrium so no heat engine can operate Robert: Fact 2 n’est ce pas? Even with T at top and T+delta T at bottom, there is equilibrium with all 3 laws. Go figure.
PS: Somewhere in there is an elevator speech to understand N&Z, I have one already posted but will leave it up to the reader to check their N&Z understanding.
Note: the density anywhere in the air column control volume is given by ideal gas law rearranged or density = n/V = P/RT so at any h in the cv, density can be computed from measuring P and T at that h, same time.
Got that? Move on….ha. Never happen, let entropy calmly increase. I dislike THAT entropy law: more reading.

288. Alan Millar says:

Lets be clear a closed system with an atmospheric temperature gradiant present could exist indefinitely without breaching thermodynamic laws.
However, that is only possible if absolutely no work is being done at all. If work is being done, and I cannot imagine a system, with a temperature gradiant, that could prevent work being done, then entropy must increase.
If work is being done then in the long run you are creating energy somewhere or you are preventing the entropy of the system from increasing. That is impossible and surely obvious to any reasonably intelligent person.
However, in an open system we have the question, can gravity affect the temperature of Earth on a continual basis. Well we know gravity can certainy affect temperatures in a system at least once.
Take a difuse cloud of particles and wait for gravity to compress them and you will certainly see a localised increase in temperature of the system. Not only that the gravitional effect is the ultimate cause of something like the Sun continuing to increase its temperature for many billions of years. So you would need to define the statement ‘once’. If ‘once’ is taken as the period between the life and death of the Universe then that would be continuously for ever.
We know that Jupiter is radiating more energy than it receives and this is ultimately due to the gravitational effect. This process has been going on and will continue to go on, for billions of years.
Is this just ‘once’ or continuous? It depends on your definition of once.
In addition is any of this gravity induced temperature difference helped along by the addition of energy from the Sun moving particles to a higher potential energy within the system making more energy available to the gravitational effect, which we know for sure increases the temperature of the planet. It must do, the exchange of energy must be producing work in the atmosphere.
So the question is, given that the Earth also receives energy continuously from the Sun, does this mean that there is a continuous temperature increase in the Earth’s system caused by the effect of gravity.
Why wouldn’t it? It is just expanding the period of ‘once’, which we all agree gravity can iat least increase the temperature of a system by.
Alan Millar

289. jjthoms says:

Hans Jelbring says: January 20, 2012 at 11:03 am
In the case of my model atmosphere there is a temperature difference that can be used for energy extraction. That can only be done by moving energy outside the closed insulated atmosphere. In such a case energy will be removed from the inclosed atmospherea and its average temperature would sink. However such a machine is not allowed since the atmosphere was inclosed and no energy at all was allowed to enter or leave the system.
======================
The average temperature may fall but the thermoelectric effect relies on temperature difference NOT absolute temperature.
Therefore, providing your hypothesis that the adiabatic lapse rate is fixed (10K/km), then your theory predicts that the temperature difference between top of column and bottom of column will be maintained. Therefore it is possible to extract the same power from the column for ever (or at least until the lower electrode reaches absolute zero!

290. Willis Eschenbach says:

Louis Hissink says:
January 20, 2012 at 4:46 am

Willis,
please get back to me via email, not here – I just don’t have the time.
Put simply, ignoring the electrical input into the earth system will lead you down many, intellectually attractive, paths.
Have a look at plasma physics and its applicability to your topics – you might be more than surprised,
Louis

Thanks, Louis. Very little is known about the effect of electricity on the climate, despite its obvious involvement (lightning, charge separation in clouds, auroras, the ionosphere, sprites and jets, cloud nucleation, the list goes on).
For this topic, however, we’re away from electricity. I do have a keen interest in the question, and I think it is an important one we’re just starting to investigate but this thread is about the Jelbring hypothesis, a very different question.
Thanks,
w.

291. Willis Eschenbach says:

MarkW says:
January 20, 2012 at 5:11 am

I’m looking at the problem from a different direction. That of stability. Think of a column of air running from the ground to space. The temperature of this column of air at the very top is fixed. It is the temperature of space itself.

Let me stop you there and say that a) space has no temperature and therefore b) the top of the atmosphere cannot be “the temperature of space itself”. Since your exposition clearly depends on those errors, you’ll have to start again.
Sorry,
w.

292. Willis Eschenbach says:

steveta_uk says:
January 20, 2012 at 5:13 am

Willis (or Dr Brown) the case for the isothermal cylinder seems to be fairly well established.
But on Earth, any given area on the surface has a conical section of atmosphere above it, and by my sums, I’d expect that if you have 15C at the surface, you’d expect to see about 13C at 15km simply due to the larger volume.
Not sure this has any implications for the overall argument or not.

Since gravity has no effect on temperature, why would the shape of the container have any effect at all? The shape of the container, whether a cone or a cylinder or a pentagram, doesn’t have some magic ability to mystically give gravity the power affect temperature. Well, maybe the pentagram …
I’d say you have a problem in your assumptions, steve.
w.

293. DeWitt Payne says:

Willis,

It helps me to determine if someone else understands something, under the principle that if you can’t explain it clearly, you don’t understand it clearly.

This explains why no one can give a clear explanation of quantum mechanics. According to Feynmann, nobody understands quantum mechanics.

294. Willis Eschenbach says:

capt. dallas says:
January 20, 2012 at 5:20 am

… Conductivity is generally assumed negligible in radiant atmospheric physics. The possibility that it is not negligible, reflects poorly on the estimates of the “radiant” portion of the ATMOSPHERIC EFFECT.

I’ve not usually seen that assumption made. In general, conduction of both sensible and latent heat is not “assumed negligible” unless it is in fact negligible for the particular phenomenon under study.
w.

295. Joel Shore;
Dave, we all know that you have become completely obsessed with this particular issue…but you have failed to refute both my and Willis’s rough quantifications of its magnitude and hence you are continuing to “make a mountain out of a molehill” on this subject.>>>
Get off of it Joel. I keep pointing out that the upper bound is not the important one to understand, it is the lower bound, and you keep coming back with noise about the upper bound. I’ve even provided sample calculations showing what a realistic estimate of the EFFECTIVE black body temperature of earth should be based on an “average” of 240 w/m2 which you have studiously avoided.
If you calculate a realistic surface temperature for earth based on actual variance of insolation, you arrive at a value of about 140K. That is the EFFECTIVE black body temperature of earth. 253K can only happen if insolation is 100% uniform and with half the earth being 0 w/m2 at all times, that notion is totaly ludicrous.
140K is far more realistic. If I accept for the moment that the earth average is anywhere near 288K, that leaves one looking for an explanation of a temperature increase of nearly 150K, not the 33K we keep on seeing quoted.
As I have asked you previously, stop modeling the error in the 288K number and start modeling the effective black body temperature of earth based on insolation varying from 0 to 1000 w/m2 on a daily day/night basis and on a tropics to poles basis. Show me what a realistic EFFECTIVE black body calc for 240 w/m2 “average” should be. Why are you afraid of coming to grips with this number? How can we possibly have a discussion of the physics required to raise surface temperatures by some amount due to the GHE when we start the discussion with a GHE number that it totaly, completely, and ridiculously, WRONG?

296. Willis Eschenbach;
But heck, let’s play it your way. You say you can do it if we break it up into pieces. OK, give me the elevator speech for the first piece of the lot, we’ll start with that.>>>
Already did. Several times.

297. Willis Eschenbach says:

John Mason says:
January 20, 2012 at 5:56 am

Why is the N Z paper called a gravity model? I always interpreted their model as a delay model. Sun heats the surface through a largely transparent medium. The surface heats this transparent medium though particle contact. Eventually this distributes through the transparent medium.

Despite repeated calls, no one has yet given the “elevator speech” about how N&Z actually works. Someone above said it’s all far too complex to be explained simply … riiight.
My point is that I don’t know how the N&Z model works, and if you do, please give us the elevator speech so we can all understand how it’s supposed to go.
w.
PS—I also don’t know what you are calling a “delay model”.

298. RE: Jelbring at 12:15 pm
You criticize my use of elevator speech (or verbal proof, take your pick) without addressing its conclusion. You say that there should be two different lapse rates, then go on to say something about equal masses. I never specified equal masses, in fact with two different gasses, with different Cp and probably different densities, there is no reason to expect equal masses or densities at intervals r from A to B.
You agree with me that there will be different lapse rates, so therefore, there can be only one point C along the tubes where they have the same temperature. At all other points (not C), the temperatures will be different between the tubes. Different temperatures means heat flow at the window at point B. Heat flow is not equilibrium, therefore there is a contradiction. Modus tollens.
The tubes must remain isothermal, same temperature at all r.
It problem is the uniform insolation, dead planet, without day-night, assumption. There isn’t a planet in the universe above 3 deg K that fits that assumption. Because planets are not uniformly heated, have a night and day, some deg of radioactive internal heating, they have non-zero real lapse rates, so we feel that it must also be so in the dead planet case. That is was the bugaboo that haunted me. Until I realized that uniform insolation requires a uniform radiator at distance at the same temperature.
My take away from these long threads this week is that the uniform insolation case requires an isothermal atmosphere (zero real lapse rate ) regardless of composition. Isothermal atmosphere is worthless to study in climate science. Therefore uniform insolation cases are worthless to study. [Watch the fur fly now!]

299. Willis Eschenbach says:

JJThoms says:
January 20, 2012 at 6:03 am

… Gravity is static it does no work. If gravity maintained the adiabatic lapse rate temperatures the it would be magically operatinhg as a maxwell deamon.

Quite true, many thanks.

By the way look up “vortex tube” for a way of separating hot and cold air!

I first read about the Hilsch Vortex Tube in the “Amateur Scientist” column back in the sixties when “Scientific American” used to actually be about science. I machined one up a decade or so ago out of a block of aluminum, they are amazing. I could get about 100°F difference between the hot and cold ends.
w.

300. DeWitt Payne says:

Alan Millar says:
January 20, 2012 at 1:39 pm
Lets be clear a closed system with an atmospheric temperature gradient present could exist indefinitely without breaching thermodynamic laws.

Wrong. The mechanism of heat conduction cares nothing about gravity. It only cares about a temperature difference (gradient). Is the temperature at the opposite ends of an insulated (say enclosed in a high vacuum chamber) bar of copper different if it’s vertical rather than horizontal? The gravitational potential energy of the copper atoms at the top of the bar is higher than for the atoms at the bottom of the bar.

However, that is only possible if absolutely no work is being done at all. If work is being done, and I cannot imagine a system, with a temperature gradiant, that could prevent work being done, then entropy must increase.

Exactly the opposite. It is only possible if work is being done, i.e. something is moving the air up and down in the column to establish the adiabatic profile. At the adiabatic profile, the work done would be very small, but even with neutral buoyancy at all altitudes, you can’t move something without doing some work. Since work is being done, the average temperature in the volume will also increase over time Conduction does no work. It simply increases the entropy of the system.

301. Willis Eschenbach says:

OzWizard says:
January 20, 2012 at 6:43 am

Willis,
N & Z have indeed produced a game-changer here and no thought experiment is needed to understand their ‘Unified Theory of Climate’.

Great! You understand it! So give us the clear, concise version of their theory called an “elevator speech”, that not only says what it does, but how it does it.
I’ve asked a lot of people but you’re among the first to claim to understand it, and the other claimants haven’t come through with their elevator speeches, so you could be the first off the blocks.
w.
PS—please don’t mention atmospheric radiation in the elevator speech, as N&Z say the following:

We show via a novel analysis of planetary climates in the solar system that the physical nature of the so-called GH effect is a Pressure-induced Thermal Enhancement (PTE), which is independent of the atmospheric chemical composition.

In other words, their theory doesn’t require GHGs to work … and so neither can your explanation.
All the best,
w.

302. Willis Eschenbach says:

DirkH says:
January 20, 2012 at 6:57 am

DirkH says:
January 20, 2012 at 3:54 am
“And that is the stable configuration, not the isothermal one.”
Looks like I misunderstood the definition of “isothermal” – and my explanation is in no contradiction to Willis’ isothermal configuration. So it seems Willis and I agree that we will observe the lapse rate as defined by the Ideal Gas Law. Sorry for any confusion.

Say what? QUOTE MY WORDS. I have no recollection of anything even remotely resembling that. I say the column will be isothermal, meaning all at the same temperature top to bottom. If not, you could pull work out of it, and that would be perpetual motion.
w.

303. DeWitt Payne says:

JJThoms and Willis,
You can often see Hilsch Vortex tubes in use in Formula 1 pits between sessions. They use them to keep the drivers cool while they’re waiting in the cockpit to go back out on the course. The air hose connected to the middle of a metal tube with a small diameter tube on one end and a large diameter tube on the other end is a dead giveaway.

304. Joel Shore says:

davidmhoffer says:

If you calculate a realistic surface temperature for earth based on actual variance of insolation, you arrive at a value of about 140K. That is the EFFECTIVE black body temperature of earth. 253K can only happen if insolation is 100% uniform and with half the earth being 0 w/m2 at all times, that notion is totaly ludicrous.

As I have asked you previously, stop modeling the error in the 288K number and start modeling the effective black body temperature of earth based on insolation varying from 0 to 1000 w/m2 on a daily day/night basis and on a tropics to poles basis.

Dave, repeat after me, 100 times if you have to: “The local value of the insolation does not determine the local temperature of the Earth. It does not even come close…It does not even come sorta, a little bit close! It is freakin’ ridiculous!” I don’t know about where you live, but where I live I’ve never seen the temperature drop down even close to the 3deg background temperature at space at night. In fact, the coldest temperature recorded on Earth isn’t even close to that!
There is absolutely no justification for using the variation in local insolation to determine an effective blackbody temperature of the Earth…None, whatsoever. Nada! It is an extremely silly thing to do. What could possibly be your justification for thinking this number is at all useful? Even on the airless moon, where the diurnal cycle is much longer and the heat capacity is much lower and convective transport of heat is practically non-existent, this is not all that good approximation for what the local temperature is going to be…at least once you get just a few cm down below the surface.

305. Ged says:

I think the problem with this experiment, the more I read it, is that it’s being forgotten for a gas to be a gas it has to be receiving a source of energy. Otherwise, it would cease being a gas and settle on the bottom of its containing (i.e. Pluto’s atmosphere); as it would lose all its energy to its surroundings (which ultimately lose their energy to space, which ultimately spreads out across the universe as the CMB, which will ultimately lead to the heat death of the universe according to Entropy and how we currently understand physics). The atmosphere’s temperature difference could do work, as that difference is captured energy from the Sun, and thus can be recaptured if one figured out a way to do so.
Basically, we cannot create a rational situation where energy input, and thus energy gradients, are separated out from the system. We can’t just say “here we have an isothermal gas doing nothing”. Shoot it off into space and it’ll soon turn solid! The container its in itself would act as a heat exchanger, as there is no perfect insulator.
In short, are we saying anything logical or reasonable about reality with these thought experiments I see people running?

306. Jordan says:

Robert Clemenzi says: “The only way to transfer heat to space is via radiation, and the only way for the atmosphere to loose heat to space is to have greenhouse gases that radiate energy.”
Robert – not so. All gases radiate. Search for “emissions spectrum”. wikki will give you a good introduction.

307. Alan Millar says:

“DeWitt Payne says:
January 20, 2012 at 2:14 pm
Alan Millar says:
January 20, 2012 at 1:39 pm
Lets be clear a closed system with an atmospheric temperature gradient present could exist indefinitely without breaching thermodynamic laws.
Wrong. The mechanism of heat conduction cares nothing about gravity. It only cares about a temperature difference (gradient). Is the temperature at the opposite ends of an insulated (say enclosed in a high vacuum chamber) bar of copper different if it’s vertical rather than horizontal? The gravitational potential energy of the copper atoms at the top of the bar is higher than for the atoms at the bottom of the bar.
However, that is only possible if absolutely no work is being done at all. If work is being done, and I cannot imagine a system, with a temperature gradiant, that could prevent work being done, then entropy must increase.
Exactly the opposite. It is only possible if work is being done, i.e. something is moving the air up and down in the column to establish the adiabatic profile. At the adiabatic profile, the work done would be very small, but even with neutral buoyancy at all altitudes, you can’t move something without doing some work. Since work is being done, the average temperature in the volume will also increase over time Conduction does no work. It simply increases the entropy of the system.”
Are you bereft of understanding?
Did I not say that I could not imagine any system with a temperature gradiant that could stop work taking place?
You have just said the same thing using different words!
Sheesh!
Alan

308. Joel Shore says:

davidmhoffer says:

140K is far more realistic. If I accept for the moment that the earth average is anywhere near 288K, that leaves one looking for an explanation of a temperature increase of nearly 150K, not the 33K we keep on seeing quoted.

We know the explanation of the other ~100K: The explanation is simply this – Different temperature distributions will have different average temperatures. Any temperature distribution that emits 240 W/m^2 into space is compatible with the energy balance of the Earth. Hence, you can have all sorts of temperature distributions that will have average temperatures less than 255 K. Which one is chosen for the Earth or for any other celestial body depends on things like the variation (in space and time) of solar insolation on the body, the heat capacity of the solid and liquids at the surface, the heat capacity of the atmosphere, the heat transport in the atmosphere and in the solids and (especially) liquids at the surface.
You think there is some great mystery to explain…but there is not.

309. Ged says:

“If not, you could pull work out of it, and that would be perpetual motion.”
But Willis, all gases can do work. To be a gas means it has to have stored energy in kinetic motion, making the molecules move too much to stick together as a liquid and then a solid.
You can get energy back out of any gas when it condenses, and from any liquid when it solidifies. The heat of condensation and heat of fusion. It would not be perpetual motion, because any energy we take out of a non isothermic gas will simply drive the entire column towards condensation, and eventually the “atmosphere” will simply settle as a solid. And, if we drag out every ounce of kinetic motion, we can get all the energy from it till it hits 0 K.
I think this is where the logic is going awry. There is always a kinetic energy difference between each molecule in a gas (a distribution as you point out), and that difference turns to potential energy as one moves against a gravity field. But if you try to use this difference to do work, you lower the average temperature of the entire column, even if there is a temperature gradient in the column (the top colder than the bottom). The top will cool fastest, and the gas will begin to settle, forming condensate on the sides of the container. The bottom would stay warmer and condense last, allowing some molecules to continue zipping around (the highest energy part of the distribution); but the pressure of the gas would steadily decrease.
Isothermal has nothing to do with anything from what I see the more I think of it. Work is done by the entire column or not; any gradient itself does and cannot do work, as affecting the gradient changes the entire average distribution and removes energy from the entire column of gas.
Again, perpetual motion comes in nowhere; because gas is a high energy phase of matter, and matter can change states.

310. DeWitt Payne says:

Alan Millar,

Did I not say that I could not imagine any system with a temperature gradiant(sic) that could stop work taking place?

That’s not at all what your words said. You said:

Lets be clear a closed system with an atmospheric temperature gradiant(sic) present could exist indefinitely without breaching thermodynamic laws.

And that bolded part of your statement is still wrong. Unless you meant “could not exist indefinitely” instead of could. I’m commenting on what you actually posted, not what you may have meant.

311. Surely centripetal force has also to be taken into account?

312. Stephen Wilde says:

Joel Shore said:
“Which one is chosen for the Earth or for any other celestial body depends on things like the variation (in space and time) of solar insolation on the body, the heat capacity of the solid and liquids at the surface, the heat capacity of the atmosphere, the heat transport in the atmosphere and in the solids and (especially) liquids at the surface.”
Hey Joel, I think you are nearly there but not quite.
This is how it works:
The oceans control air temperatures as per my Hot Water Bottle Effect.
I’ve also said that the oceans should be considered as part of the atmosphere and I have explained in detail why the ocean heat content and the rate of energy flow from ocean to air is also pressure dependent just as is the ATE of Nikolov and Zeller.Therefore both being pressure dependent the oceans cannot alter the ATE. In fact they are an important part of setting it on our particular planet.
The ATE effect is dominant in the atmosphere and governs the temperature gradient from surface to space. We could adopt the term Ocean Temperature Effect (OTE) for the region below the ocean surface but I prefer the term ATE to cover both, with the oceans just being considered as a part of the atmosphere. Obviously there is a discontinuity at the water/air interface but the evaporative process deals with that to leave ATE in the air undisturbed.
ATE is far more powerful than the misleadingly named and probably non existent GHE from GHGs because the former involves the entire atmospheric mass whilst the latter involves only GHGs which are a not a sizeable proportion of total mass.
What I think happens is that ATE is in complete control and all the other features of the system from the bottom of the oceans to the top of the atmosphere organise themselves around ATE to maximise system entropy (the tendency of any system to become less organised over time). In the case of an irradiated planet the concept of it becoming less organised over time involves the removal of energy to space as fast as possible given the constraints of basic physics.
The system always responds negatively to any factor that tries to alter the surface temperature fixed by the ATE because any deviation from the ATE represents a reduction in efficiency as regards the rate of energy loss to space. As far as we can tell it always succeeds leaving ATE unaltered.
The way that the system organises itself depends on the composition of the component elements but due to the dominance of the ATE the only effect from composition differences is to change the rate of energy throughput within each section of the system so that the surface temperature does not change.
However a faster throughput of energy within a particular section of the atmosphere will result in higher temperatures wherever more warm air passes more often across sensors situated within that section but that is a result of energy redistribution and not a sign that the equilibrium temperature of the system has changed.
The ability to redistribute energy in that way (differentially in different sections of the system) is in fact what makes the system flexible enough to maintain the ATE.
Thus pressure and energy input give us the ATE but everything else including GHGs only affects the rate of energy throughput and not the ATE itself.
If GHGs increase then the energy throughput increases to leave the ATE stable and if GHGs decrease then the energy throughput decreases to leave the ATE stable.
N & Z are carefully collating data to verify that proposition. If they do indeed get accurate enough planetary surface temperaures to prove the dominance of the ATE from planet to planet then all that other factors can achieve is to work around the ATE just as I suggest.
So far they have firmed things up by getting a more accurate lunar surface temperature and corrected an apparent error in the application of the S -B equations.
The resulting figures are in supprt of the proposition that ATE governs the surface temperaure regardless of all other potentially confounding factors.

313. Jordan says:

DeWitt Payne says: “The mechanism of heat conduction cares nothing about gravity. It only cares about a temperature difference (gradient)”
I know what you mean – but are you missing something?
Imagine a heat engine with a low altitude heat source (extract heat here) and high altitude sink (dump heat at the assumed cold upper atmosphere). The plan is to exploit a temperature difference. The link between the source and sink is solid (e.g. electrical conduction through copper).
To simplify things, consider operation in terms of a single molecule of the atmosphere. The heat sink adds kinetic energy to the molecule at altlitude. The molecule (in the fullness of time) falls towards the heat source, and gains kinetic energy. At the source, it has the capacity to pass an additional chunk of kinetic energy to the machine.
As you’ll know, this doesn’t work. We appear to have passed energy from the sink to the source to create a boost for the engine.
What went wrong?

314. Myrrh says:

And therein lies the problem, that you’re talking about perpetual motion and you don’t know it. Hans, you are indeed proposing perpetual motion. You are saying that gravity separates the warm and cold molecules.
Don’t expect maths terms used correctly, but, isn’t weight a ‘function’ of gravity? Molecules only have weight because of gravity, which is why the ideal gas law doesn’t have gravity, the ideal gas doesn’t have weight or volume, so, a hotter real molecule has weight and will become less dense and therefore lighter as it heats up and so will spontaneously rise unless work is done on it to stop this, and as it rises into the colder regions it cools, becoming heavier it sinks where it will again gain some heat and so the cycle continues, doesn’t it?
Isn’t the Earth as is a fairly good approximation to this if one takes out the spin? All the spin does is put in a some interesting routes for volumes of air, which with or without the spin naturally rise as heated and gravitate to the colder poles (heat flows spontaneously from hotter to colder). Did you like the use of gravitate… 🙂 I only noticed after I’d typed it. Anyway, this is what I read when looking up how our winds work.
Our weather is very energetic because we have the Sun’s imput, but that only exaggerates what gets it all moving, which is the difference in temps between land and seas and so cold air moving in to under hot air rising such as coastal regions, morning and evening differences, and cold air compressing the molecules beneath as it descends again after being for a while hot air rising, both these create winds. Without the ocean one of the wind systems would be out, but, I suppose, as long as there is a temp difference among the rocks or whatever is on the surface, there should be winds created from the temp differences of the volumes of air above them.
If all the surface was of the same material, the same kind of rock, I suppose it would just, somehow, rise and fall simply from the effects of gravity, that is, weight of the molecules, as they changed densities on becoming hotter and colder.
Perhaps one could design an optimum mix of gases to exaggerate these differences in weight of gravity..?
Anyway, gravity separates molecules by weight, hot or cold doesn’t make any difference to gravity, that just makes a difference to the molecule – expanding, becoming less dense with heat, contracting, becoming more dense with cold. the molecules have a different weight relative to each other at the same temperature anyway.

315. PeterGeorge says:

I think I have an answer that I actually believe.
1) Temperature, BY DEFINITION, is the inverse of the rate of change of entropy with respect to energy (with a proportionality constant). That means, when a unit of energy is transferred from a relatively warm object to a colder one, the entropy of the warmer object decreases, but by a relatively small amount, because high temp means low rate of change of entropy, and the entropy of the colder object increases by a larger amount (low temp means high rate of entropy change). So, the total entropy increases.
2. The total entropy of an isolated system must stay the same or increase (2nd law of thermodynamics).
3. If we make the Earth an isolated system by putting a perfect, reflective bubble around it, then it must obey the 2nd law: its total entropy can remain the same or increase; it can never decrease.
4. We neglect the interior of the Earth, and the oceans, because the effect we’re discussing should apply on a planet with a cold interior and no water.
5. If we initialize the atmosphere of this world with regions of unequal temperature, then occasionally, through simple conduction or via radiation, net energy will get transferred from a warmer region to a colder region and when it does, the total entropy of the system will increase IRREVERSIABLY – the system as a whole will never be able to return to the lower entropy state.
6. Therefore, there is an inevitable process by which temperatures will equalize, pushing entropy up, or there is a state with regions of unequal temperature but no possible means for net energy transfer between them – a highly improbable scenario and certainly not the general case.
7. Willis is right. Gravity won’t produce any temperature gradient. It does, of course, produce gradients in pressure and total energy content (as a function of temperature), but not temperature.

316. pochas says:

I think this thread has jumped the shark.

317. Willis Eschenbach says:

A physicist says:
January 20, 2012 at 8:53 am

Yet another elevator argument for isothermal (same temperature) atmospheric equilibrium is as follows: we imagine a very tall (10 km tall) thermopile column (a device that converts temperature differences to electricity), and we insulate the body thermopile column so that only its top and bottom exchange heat with the atmosphere.
Now supposing that the upper air is colder than the lower air, our thermopile generates electric power continuously and forever, with no external source of power. Which is impossible. And so we conclude that, at equilibrium, the entire atmosphere must be at one temperature.
Of course, in the real world, such a thermopile column would generate electricity. And this electricity would constitute (ultimately) a form of solar power, deriving from sunlight acting to warm the earth, thus creating rising thermals that stir the atmosphere, creating a temperature gradient that the thermopile can exploit.
This is one more line of reasoning showing that the isothermal folks have got the thermodynamics right.

This to me is the fundamental argument.
This is why any and all arguments about the means of how gravity supposedly separates by temperature, or the strong arguments from various people about why it clearly must separate by temperature, are meaningless. Not because the means are wrong or falsifiable, but because the outcome is impossible. Robert Brown has capably and clearly given (and continues to give) the “why it is isothermal” speech. He has done the best job to date of explaining the means and the whys.
But set all of that aside:
IF GRAVITY ACTUALLY SEPARATES TEMPERATURE, WE HAVE FREE ENERGY FOREVER!
If sealed thermally isolated containers of air were to gravitationally separate, with warm air at the bottom and cool air at the top, then we could build tall insulated cylinders and pull power out of them forever.
Does anyone really, in their heart of hearts, regardless of the logic of any and all arguments, believe that we can constantly and unceasingly pull energy out of a thermally insulated column of air?
Because make no mistake about it. That is what Hans Jelbring is claiming.
w.

318. Marc77 says:

Gravity generates the adiabatic lapse rate by converting kinetic energy to potential energy. If the atmosphere was full with greenhouse gases, it would equilibrate with radiative transfer. The only reason the atmosphere would have an adiabatic lapse rate with greenhouse gases is if the ground was warmer than space. Because with radiative transfer, different bodies will equilibrate to an identical temperature.
Now, I think it is a question of optical thickness to IR. Space does not emit a lot of IR, so there is a differential of temperature at the radiative level between space and the ground. Now, here’s a small piece of thinking that is probably wrong, but I don’t know why. The mass of the atmosphere is equivalent to 5m of ground. The interior of the Earth is very warm and, I guess, optical thickness is probably the reason why the ground is not has warm. The highest variation of temperature you can find in the ground is about 30K/km. This is equivalent to 0.15K for 5 m. So, if the atmosphere is able to generate 33K for the whole atmosphere, it would mean that a molecule of a greenhouse gas is around 220 times more optically thick than a molecule of the ground.
From that I have 2 questions:
1- Are greenhouse gases 220 times more optically thick than the ground?
2- Why?

319. Stephen Wilde says:

Gravity does not separate by temperature. It separates by mass.
Jelbring, Nikolov and Zeller (and me) accept that in the absence of an energy source the column will become isothermal.
It is only when energy is added that the temperature gradient forms as a result of more densely packed molecules converting a greater proportion of the incoming radiation to kinetic energy.

320. Phil. says:

davidmhoffer says:
January 20, 2012 at 1:55 pm
If you calculate a realistic surface temperature for earth based on actual variance of insolation, you arrive at a value of about 140K.

That is a totally unrealistic surface temperature as it assumes the dark-side of the planet is at absolute zero, which is a totally unrealistic case and far from what is observed, it isn’t even realistic for the moon which has a 14-day ‘night’ and no atmosphere!

321. Willis Eschenbach says:

Robany says:
January 20, 2012 at 9:20 am

I’ve been trying to wrap my head around the thermodynamic arguments for the last few days. The isothermal column of air argument seems to have some problems:
1) The atmosphere has a measurable temperature gradient. An argument that suggests it should be isothermal seems to immediately be falsified by contradiction.

Robany, you are right about the real atmosphere. We are talking about the atmosphere in Stygia, the planet described in Hans Jelbring’s thought experiment. Our real atmosphere is not at equilibrium so (as you note) it has a temperature gradient. Take away all external sources of energy, as in Jelbring’s thought experiment, and at equilibrium it will be isothermal.
w.

322. Trick says:

Willis says at 1/20 2:19pm:
“I say the column will be isothermal, meaning all at the same temperature top to bottom.”
This violates the 2nd law, KE + PE = constant at each h in the presence of an inexplicable gravity field in the gaseous cv of interest, namely an adiabatic (no gain or loss of heat from CV) GHG-free air column.
Willis’ statement, I believe, derives from the top post which says in part:
“On average, just as many molecules move up, with exactly the same velocity/kinetic energy profile, as move down…”
This too is a violation of 2nd law conservation of energy PE + KE = constant since in my view: each molecule moving up in the presence of an inexplicable gravity field cannot have exactly the same velocity/kinetic energy as those moving down in presence of gravity field PE (= ngh) since KE changes with h for energy constant to stay the same, therefore KE must change. Only outlaws need run from this sheriff.
The kinetic energy will vary with h thus P*V will vary and since V is constant in the cv, P must vary. Thus ideal gas thru PV=nRT must vary the temperature so the cv of interest is a non-isothermal air column. No work can come out of it b/c air column’s one macro object is in equilibrium given all 3 laws so we do not have free energy forever (Willis says at 1/20 3:18pm).

323. Bart says:

Bart says:
January 19, 2012 at 11:28 pm
Unfortunately, I find that my argument regarding non-constancy of the solution is lacking. The modified and adjusted zeroth order Bessel function of the second kind is an eigenfunction, but so is the modified and adjusted zeroth order Bessel function of the first kind, and these can be independently weighted with a time dependent amplitude function. I believe, offhand, that these may be added in such a way as to produce a constant. Therefore, a result which thus converges to a constant is possible. I think it is not physically realizable, but I haven’t <i<proven it yet.
So, I must come up with another argument justifying the approach to 0K at infinity. When I resolve this, one way or the other, you all will be the first to know.
It seems self-evident, though. Using the Earth as an example, with the standard greenhouse hypothesis, it otherwise never would get warm enough to produce water vapor to initiate the greenhouse warming. This is an unstable situation, because the Earth always has the capability to nosedive back to -18C, and become a bleak and barren ice planet. In Nature, whatever can eventually does. That which is not forbidden is compulsory.
Anyway, it’s back to the books for proof. Will keep you all posted.
Willis Eschenbach says:
January 19, 2012 at 11:48 pm
<So in the Jelbring thought experiment you are saying the atmosphere never, ever achieves thermal equilibrium? If not … why can’t we pull work out of it with a thermocouple?"
You can. Remember, there is an outside energy source which is constantly adding energy to the system. Is the Earth at equilibrium? How do windmills work?
Joe Born says:
January 20, 2012 at 5:30 am
“An atmosphere of the type you describe would acquire energy from its source only when its temperature is less than the surface’s.”
This is not a constraint. The surface can get hotter at the same time. Stefan-Boltzmann does not limit it as A) the system is not in steady state and B) even in steady state, SB only puts an upper bound on outgoing radiative energy, but not an upper bound on temperature.
Besides, constant flux from the external heating radiator is more like current than voltage. See section 2.3 here.
DeWitt Payne says:
January 20, 2012 at 12:38 pm
“You can also assert all you want about the SB equation not applying, but you have given no evidence or citation that it doesn’t.”
But, you have no evidence or citation that it does. SB is always couched in terms of steady state, or at least a quasi-steady state.
SB radiation is an outlet for energy flow, so that incoming and outflowing are equal in the steady state. When you have energy conducting outward in large volume, then the individual particles of the surface do not have to be radiating to maintain balance.
“Even if the emissivity does vary with wavelength and angle, one can still integrate the Planck equation, B(λ,T) and get the total emission.”
The Planck distribution describes the energy distribution of particles making up the surface when in thermodynamic equilibrium and unable to transition to a lower energy state through any means other than radiation.
“A molecule that was actually in orbit would indeed have very high kinetic energy relative to the molecules around it.”
We don’t consider that in calculating temperature, though. As I pointed out, satellites moving in LEO at 7500 meters per second do not radiate as though they were at 30,000K. A full treatment would need to be couched in terms of relativistic four-momentum, which is always conserved, and for which the time-like element is the energy. I don’t think we really want to get into that, here.
DeWitt Payne says:
January 20, 2012 at 9:39 am
“As pointed out above, your first crack at the capacitor example was correct.”
As I pointed out in the reply to Joe, no it isn’t.
“Even a constant current source reverts to a constant voltage source at some voltage.”
Not an ideal current source. This is like the assumption of an ideal non-radiating atmosphere. In fact, at some point, every real current source breaks down, and every real atmosphere radiates.
“Bart,Your argument begs the question.”
You are right. It does. See the top response to myself in this post. I did not recognize it because I had dismissed the other eigenfunction and thought no more of it.
Phil. says:
January 20, 2012 at 1:02 pm
“What it should say is that ‘the heat accumulates in the atmosphere until the layer of gas nearest the surface reaches the surface temperature at which point heat transfer ceases due to ΔT=0.”
The surface temperature is increasing, too. There is no limit on the temperature of the surface, only on radiated energy. If you are not at equlibirum, then you are not generally radiating at the SB limit. That which is not forbidden is compulsory.

324. Downdraft says:

I am still puzzling over the idea that a column of air will reach an isothermal state or not. I took Dr. Brown’s explanation as a starting point and made changes to it that reflect my view. I hope he doesn’t mind. Who would think that such a simple thought experiment would be so complex.
Imagine a plane surface in the gas. In a thin slice of the gas right above the surface, the molecules have some temperature. Right below it, they have some other temperature. Let’s imagine the gas to be monoatomic (no loss of generality) and ideal (ditto). In each layer, the gravitational potential energy is constant but the upper layer has a higher potential energy. Bear in mind that only changes in potential energy are associated with changes in kinetic energy (work energy theorem), and that temperature only describes the average internal kinetic energy in the gas.
In equilibrium, the density of the upper and lower layers, while not equal, cannot vary. Which means that however many molecules move from the lower slice to the upper slice, exactly the same number of molecules must move from the upper slice to the lower slice. They have to have exactly the same velocity distribution moving in either direction. However, the molecules moving downward are accelerating, therefore increasing in kinetic energy while the ones moving upward are losing kinetic energy for potential energy. The molecules below had a higher temperature, and have a different MB [Maxwell-Boltzmann] distribution, with more molecules moving faster. Some of those faster moving molecules would have the right trajectory to rise to the interface (slowing and cooling, sure) and carry energy from the lower slice to the upper. The upper slice (lower temperature) has fewer molecules moving faster —However, at the interface, the MB distribution is equal owing to the average energy of the upward and downward flows being equal There are therefore equal molecules that move the other way at the same speeds that the molecules from the lower slice deliver (allowing for gravity). Thus, average kinetic energy is unchanged in both layers. On average, just as many molecules move up, with exactly the same velocity/kinetic energy profile, as move down, with zero energy transport, zero mass transport, and zero alteration of the MB profiles above and below, only when the upper slice is cooler than the lower, due to the conversion of potential energy to kinetic energy as they fall. Therefore, a vertical column of air at equilibrium will be cooler at the top than the bottom.

325. Willis said, “I’ve not usually seen that assumption made. In general, conduction of both sensible and latent heat is not “assumed negligible” unless it is in fact negligible for the particular phenomenon under study.”
Convection and Latent are considered. I have not see conduction properly considered. CO2 impacts the conductivity of mixed gases as well as the radiant impact. That impact is considered negligible when it appears not to be. Trenberth’s latest cartoon reduced the conductive impact, (thermnals he uses for combined conductive/convective) even while increasing the surface temperature. If you have a link that addresses conductive change, I would like to see it.

326. Jordan says:

“IF GRAVITY ACTUALLY SEPARATES TEMPERATURE, WE HAVE FREE ENERGY FOREVER!”
This assumes a heat engine can transfer energy from its source as efficiently as transfer of energy into its source. I do not believe this assumption has been justified where conditions at the source are not the same as conditions at the sink. .
An ideal sink assumes the same temperature as its surroundings because there is perfect heat transfer from the sink. Same for an ideal source. If the source is not ideal, the “effective” source temperature will be at lower temperature compared to its surroundings. Vice versa for a heat sink.
Consider the effect of gravity on the density of gases and the impact this can have on the ability to conduct thermal energy by conduction.
Until it is demonstrated that the physical conditions for transfer of thermal energy around the source and sink are favourable (i.e. the do not fully negate the temperature difference we are trying to exploit), the arguments in this post cannot be supported using notional heat engines.

327. Willis,
You said
” I offered up a proof that no possible mechanism involving a transparent, GHG-free atmosphere could raise the temperature of a planet above its theoretical Stefan-Boltzmann temperature.”
Sounded like a refutation to me, since there is nothing in the theory that requires greenhouse gases.
And you said:
“if you can’t explain it in an elevator speech, it [sic] you don’t understand it”
which sounds like an assertion that no one understands it, or did someone win the prize for a coherent elevator speech demonstrating clear understanding? If so I missed it. But in any case understanding a hypothesis that is wrong seems almost a contradiction in terms.
I have here some background on the journal in which the Jelbring paper appears. It provides some insight into the way in which peer reviewed journals validate or fail to validate what they publish.

328. Jordan says:

“This assumes a heat engine can transfer energy from its source as efficiently as transfer of energy into its source”
Oops – “transfer into its sink”

329. PeterGeorge said, “7. Willis is right. Gravity won’t produce any temperature gradient. It does, of course, produce gradients in pressure and total energy content (as a function of temperature), but not temperature.”
Completely isolated as in your reply, true. Gravity appears to impose a low limit on the atmospheric sink temperature to the energy required for obtaining escape velocity. Gravity interactions with the moon and sun do add some tidal energy to the system. I think the escape velocity limit is what is causing the confusion. I haven’t seen it explained very well anywhere. There are a number of things about the tropopause I have not seen explained very well.

330. KevinK says:

Willis wrote;
“If you are fighting basic ignorance of science, you will be deluged with ignorant people. Not much I can do but just keep putting the facts out there.”
With all due respect, I am most certainly NOT ignorant of science. With multiple Master’s Degrees in Optics and Electronics and three decades of reconciling computer predictions with actual observations I am quite familiar with all of the relevant disciplines necessary to understand the “Greenhouse Effect”.
Ironically enough, the FLAW in the GHE HYPOTHESIS is actually more of an accounting error than a science error. When the energy returns to the surface from the “GHG” you cannot ADD it to the energy arriving from the Sun to produce an alleged “energy budget”. The energy returning from the “GHG” has already travelled once through the system leaving cooling (at the previous location it departed from) in its wake. So we have sequential warming/cooling/warming/cooling…. events occurring from ONE bundle of energy that came from the Sun. So one bundle of energy from the Sun simply warms the surface multiple sequential times, since these warming events are followed by equivalent cooling events and are separated by finite time delays YOU CANNOT ADD THEM TOGETHER and get a correct result. Doing so is the equivalent of creating energy, which you must admit violates the First Law.
One of the clues to this accounting error is the use of the terms; “Net Energy Gain” and “Extra Energy” as used in the climate science community.
In the engineering community we use the existence of “extra energy” as a RED FLAG to tell us our analysis is wrong.
Engineers that routinely calculate “Net Energy Gains” either get fired or promoted into management.
Regarding why the Earth is at the average temperature it is, I have yet to hear any one explanation that makes common sense. But knowledge always expands and we will likely know why sometime. Although from a practical sense it seems to make very little difference.
But it most definitely is not the result of the GHE.
The GHE appears to cause some energy to travel through the system (bouncing as it where) between the gases and the surface all the while dissipating energy to Space via radiation. The end result is a slight delay to the energy as it travels from the Sun to the Earth through the Atmosphere to the Universe.
The “missing heat” is currently travelling as a spherical IR wavefront that is “X+d” light years away from the surface. In this equation X represents the elapsed time since the sunlight arrived (i.e. 100 years for sunlight from 1912) and d represents the slight delay from the GHE and is likely about 5 milliseconds. “d” is actually a statistical distribution which will of course have a different specific value for each photon travelling through the system. Some will bounce many times and take longer to exit, while others may not bounce at all and exit directly to space.
Just because people disagree with you does not necessarily mean they are ignorant of science, another possibility is that you are mistaken in some way. I know the GHE theory has been written down in papers and textbooks, but so was the theory that stress and spicy food
caused stomach ulcers.
Cheers, Kevin.

331. Bart says:

I cross posted this at an aerospace blog I frequent:
There are two ways of looking at the problem:
1) You can claim that the atmosphere will continually conduct heat away only until everything is at equilibrium, so that the surface is at the temperature set by the Stefan Boltzmann formula such that incoming and outgoing radiation balance. At this point, the atmosphere is at constant temperature throughout, so there are no more heat flows to disrupt the radiative equilibrium.
The problem with this point of view is that it is a circular argument. It iassumes a priori that equilibrium will be established, therefore the Stefan Boltzmann relationship will hold.
2) Another, equally plausible, scenario is that the system is unstable, such that equilibrium is never attained, even asymptotically. Then, the Stefan Boltzmann relationship does not hold, and there is no limit to surface temperature.
The temperature profile of the atmosphere due to the surface/atmosphere conductance has to satisfy the heat equation. Solutions of the heat equation exist for both of these alternatives, as I have had to acknowledge in my lastest posting here. But, the runaway scenario #2 is more satisfying from a stability viewpoint. If scenario #1 is the case then, since water freezes at the non-atmospheric equilibirum temperature of the Earth, a question arises as to how the effect ever got started, and there remains a possibility of slipping back to that lower energy equilibrium state.
And, if you want to know the perils of dismissing the possibility of transition to a lower energy state from a quasi-stable higher energy state… Well, the denizens of this site know where to look.
I am sifting through the problem to try to find some requirement which will decide the question one way or the other. When I find it, I will let you know. Other inputs which would contribute to that search are welcome, but baseless assertions, based on the standard way most people think things should be, are not. As of right now, mostly what I have gotten are baseless assertions that SB must hold regardless of anything else going on, and that argument has no foundation.

332. Jeremy says:

“If W=FD and F = mg then W can be done by heated air rising IF volume changes. ”
Agreed. There is no denying that hot air heated by blackbody radiation near the earth’s surface gains energy, the gas expands as it heats up and rises. As it rises it cools loses energy and the molecules have higher potential energy because they are higher up the gravity field. In essence, work done by the Sun (radiative energy) has heated the Earth and in turn heated the air. The Work is added by the SUN not gravity. Another transformation happens when the Suns radiative energy causes warmth and water to evaporate however this energy gets stored in another form of potential energy or properly described as “latent heat” – later on when water condenses this latent heat is released.
The point is that it is not “gravity” which is actually doing any of the Work or creating any energy or any heat. It is just a passive bystander. For sure as molecules move up and down in a gravitational field they gain and lose kinetic energy in exchange for potential energy but there is no Work or net energy being added by gravity itself to the system as a whole. Gravity plays a strong influencing role on atmospheric properties and how the atmosphere behaves but it does not create or add net heat to the system. External sources of Heat and Energy come from things like meteor impacts, cosmic rays, solar wind, radioactive decay, the Sun and chemical reactions.
When you drive your car or turn up the heat in your home or have a meal or pretty much anything (like breathing) then you are using up stored energy from our Sun. The Sun’s energy has been stored by plants and the main storage mechanism is to create Carbon from CO2 (that is how plants grow – by stealing Carbon from the air). Animals consume Carbon by oxidizing it with Oxygen and releasing CO2. When you burn fossil fuels then you are burning carbon energy that was stored by plants using energy from the Sun. When you use electricity then it comes from the Sun also. Even Wind Power and Hydro is all from the Sun while tidal power would be mostly Moon and Sun. Hydro power simply comes from the Sun’s energy heating water that rises and then eventually cools and condenses and precipitates at altitude on some mountain. Even in the case of Hydro power it is not gravity that provides the source of energy.
When Sisyphus pushes his boulder up the hill it would be the energy from the lunch he ate that creates the potential energy of the boulder that is released when it falls back down – gravity has not done anything.
For most of us the Sun is the source for everything including the heat engine that drives our atmosphere. There are some life forms that seem to work from heat of radioactive decay or heat left over from when the Earth formed (Sulphur based?) but the majority of life forms seem to be Carbon based.

333. Bart says:

Downdraft says:
January 20, 2012 at 3:37 pm
“I am still puzzling over the idea that a column of air will reach an isothermal state or not.”
It will, but if and only if equilibrium is established. So, it becomes a circular argument.

334. Phil;
That is a totally unrealistic surface temperature as it assumes the dark-side of the planet is at absolute zero, which is a totally unrealistic case and far from what is observed, it isn’t even realistic for the moon which has a 14-day ‘night’ and no atmosphere!>>>
EXACTLY!
The question then becomes:
WHY?
We cannot answer “why?” unless we know what the theoretical starting point is. Beginning with a theoretical starting point of 253K which can only be achieved by a uniform insolation is wrong, wrong, wrong.
How is it that everyone wants to use SB Law to calculate a theoretical equilibrium surface temperature, and when I show that the theoretical surface temperature calculated by averaging P produces a false number, everyone jumps up and says:
“well your theoretical number cannot be correct because when we look at practicaly measured instances like the moon, we don’t get anything like your theoretical number”.
AND THAT IS THE POINT!!!
The moon doesn’t reach that theoretical number because even though it doesn’t have an atmosphere, it still has:
a) heat capacity
b) conduction
so those factors tend to make the temperature more uniform even given a 14 day night. It is the exact same discussion as before. What are the factors that redistribute energy on the moon, and by how much for each, and how does that affect the measured “average” temperature across the entire surface versus the theoretical average arrived at by black body provided that conduction is zero and heat capacity is zero?
The point I’m trying to get at here is that the moon does not in fact meet the theoretical effective black body temperature profile, and hence, we can assume that the difference between the observed temperature distribution and the theoretical distribution is due to factors such as heat capacity and conduction.
The same is true of the earth except that with earth we have to throw in all the atmospheric and oceanic processes that move energy around on top of heat capacity and conduction.
The value of 255K is meaningless as a theoretical value, it applies in no way shape or form to the actual earth. We cannot possibly sort out how much of the observed temperature profile is due to heat capacity, conductance, atmospheric and oceanic processes if we start with a mythical number in the first place. If we’re going to start out with the “theoretical” black body temperature of the earth and then subtract that from the observed temperature of the earth to figure out how much of the difference is due to GHE and other factors, of what value is doing the theoretical math against a theoretical black body temperature that is wrong in the first place? Of what value is pointing out that the moon doesn’t adhere to the theoretical black body temperature in the first place when what we’re trying to measure is WHY it doesn’t match, not if it matches. Unless conduction and heat capacity on the moon are zero, why would anyone possibly expect the measured temperature profile to match the theoretical profile which is calculated in the absence of those factors?

335. DeWitt Payne said @ January 20, 2012 at 1:53 pm

Willis,

It helps me to determine if someone else understands something, under the principle that if you can’t explain it clearly, you don’t understand it clearly.

This explains why no one can give a clear explanation of quantum mechanics. According to Feynmann (sic), nobody understands quantum mechanics.

“Understand: To comprehend; to apprehend the meaning or import of; to grasp the idea of.” [from the OED]
Oddly enough, my understanding of QM came from Feynman’s lectures. Are you saying that he didn’t know what he was talking about? Or are you really Gavin Schmidt putting a different meaning on “understand”?

336. robr says:

Willis Eschenbach
For some reason the idea that the atmospheric pressure of a planet plays a dominant role in the temperature make sense to me, after all, the second law of thermodynamics is expressed in terms of entropy, pressure, volume, energy and temperature. While I have only a BSME, I thought I would look at this from an engineering standpoint. In M.E. heat transfer is by conduction, convection or radiation. My text on the subject does have some combined conduction-convection problems but radiation problems are generally restricted to heat transfer between bodies in a vacuum, except for some inside a furnace problems.
So I will looks at this as a free convection problem and while this could be solved directly from the differential equations for, momentum, continuum and, energy or the corresponding integral equation for free convection, we engineers generally use working correlations derived from experimental investigations carried out for a vast number of situations. These investigations resulted in a number of dimensionless properties derived from ratios of state properties. The ones I will use here are:
Re = Reynolds Number = U*l/v
Gr = Grashof Number = (g*l(^3)*beta*Delta-T)/v(^2)
Pr = Prandlt Number = (mu* C(sub p))/ k
Nu = Nusselt Number = (h*l)/k
Statement of the problem: What is the effect of atmospheric pressure on the free convection from a surface? I will calculate the energy needed to be input into a plate 1m X 1m so as to maintain its upper surface (lower surface insulated) temperature of 40C. I will calculate it for the plate being in 0C air at 1 Atm and 25 Atm. We need to gather some data:
L = characteristic length = Area/Perimeter = (1m X 1m)/4m = 0.25m.
v = kinematic viscosity
k = thermal conductivity
beta = coefficient of thermal expansion
Pr = coef. of dynamic viscosity * specific heat / density
From Wolfram Alpha at average air temp of 20C:
For Air at 1 Atm:
v= 15.09 X 10(^-6) m(^2)/s
k= 2.56 X 10(^-2) w/m-C
beta = 3.41 X 10(^-3)/C
Pr = 0.713
For Air at 25m:
V=6.24 X 10(^-7), k=2.68 X 10(^-2), beta=3.41 X 10(^-3) and Pr =0.726
h(what we are looking for) = heat transfer coef = Nu*k/L
Nu = 0.54*Ra(^0.25) for 2.6 X 10(^4) < Ra < 10(^7)
Nu = 0.15*Ra(^.33) for 10(^7)< Ra < 3 X 10(^10)
So at 1 Atm:
Gr = ( 0.25(^3)*9.8*3.4 X10(^-3)*40)/(15.09 X 10(^-6))(^2) = 91.724 X 10(^6)
Ra = Gr*Pr = 65.399 X 10(6)
Nu = 0.54*(65.399 X 10(6))(^2) = 48.56
h = 48.56*2.56 X 10(^-2)/0.25 = 4.98 w/m(^2)-C
Similarly for 25 Atm
h = 54.5 w/m(^2)-C
One would need to input over ten times more heat to maintain the surface temperature at 25 Atm than at 1 Atm. This says to me that I would expect to see a significant difference in the atmospheric temperature profile (with height) for identical planets except atmospheric pressure.

337. KevinK,
Thankyou for that lucid and well presented argument which I endorse right down to the fate of engineers that get it wrong!

338. Hans Jelbring says:

DeWitt Payne says:
January 20, 2012 at 9:59 am
“Hans Jellbring,
Any surface radiation power exceeding 100 W/m^2 is bull regardless if it is from equatorial, midlatitude or polar regions during days or night. Just show how this fantasy power radiation changes between day and night in polar regions as an exsample.
Here’s a plot of upwelling IR radiation measured over 24 hours at Desert Rock, NV by a SURFRAD station there. It looks to be more than 100W/m² to me. Note that the time axis is UTC. Desert Rock is -8 hours from UTC so local noon would be 2000 on the time axis.
There are seven SURFRAD stations in the US. You can access the data here.”
Thank you very much for telling me that there exist data. I don´t know if you ever heard about the Wangara and Koorin expedition i Australia. All types of mesurements were made every 3 hours for 30 days including solar irradiation and IR radiation. “The Koorin expedition, Atmospheric boundary layer data over tropical savannah land. Measurments were taken from 0 to 3000 m.
There were never any IR backradidiation or forward radiation to earth exdceeding 100 W/m^2 during this period. The book is 360 pages mostly containing data. this was during a time before “back radiation was invented”.
If back radiation existed i would be able to go out in the middle of the night and let the radiation hit my face and I would get a nice brown tan in the middle part of winter in northern Sweden when the sun is not shining at all. Even high school kid can figure out that it is impossible. Prefessor Gerlisch has written about this fraud in the G&T falsification of the Greenhouse Effect.
You might know that you quickly get a sun tan in a snowy area since the solar irradiation is coming both directly and is reflected from the snow. Photons works directly from the point they are emitted. If the infamous 390 W/m^2 plus the 330 W/m^2 “downwelling” was real we would get an equivalent to sunshine everwhere regardless if is dark or sunshine. The whole thing is just Alice in the Wonderland Fairtale.

339. KevinK says:

DR wrote;
“There is something wrong with the GHE hypothesis as it has been promoted lo these many years.. I’m not qualified to enunciate what it is in technical jargon, but I don’t need to be an atmospheric scientist or physicist to know something is wrong. Does anyone else feel like they’ve been sold a lemon? Even here on WUWT, with the arguing going back and forth, the “theory” is no better explained or proven than it was 25 years ago.”
I initially started from a position of disbelieving the stated accuracy of the computer models. We use computer models in engineering all the time and have a saying; “If your hardware does not perform as predicted by your model you need to improve your model”. The level of hubris required to predict the Earth’s temperature in 100 years is STAGGERING.
After looking into the GHE hypothesis a little bit, I am now convinced it is fatally flawed. See my previous post (assuming it went through) for details.
So I guess I didn’t actually BUY the lemon, but I did pick it up, squeeze it, look it over and then I took a pass.
Nice YouTube, I actually went to school when we still used chalkboards, is there a chalkboard museum around someplace to preserve them ?
Cheers, Kevin.

340. Q. Daniels says:

Suppose Jelbring is right, and the temperature in the atmosphere inside the shell is warmer at the bottom and cooler at the top. Then the people living in the stygian darkness inside that impervious shell could use that temperature difference to drive a heat engine. Power from the heat engine could light up the dark, and provide electricity for cities and farms. The good news for perpetual motion fans is that as fast as the operation of the heat engine would warm the upper atmosphere and cool the lower atmosphere, gravity would re-arrange the molecules once again so the prior temperature profile would be restored, warm on the bottom and cold on the top, and the machine would produce light for the good citizens of Stygia … forever.
As this is a clear violation of conservation of energy, the proof by contradiction that the Jelbring hypothesis violates the conservation of energy is complete.

The final sentence is incorrect.
What is being described is Perpetual Motion of the Second Kind, in which energy is precisely conserved.
Willis wrote:
a) show that there is no problem with a sealed system performing continuous work with no energy inputs or exchange with the outside world, (my bold)
You stipulate conservation of energy, and then suggest that energy is not being conserved. All that is being done is internal rearrangement of the sealed system.
As for your challenge, it will be done, in an unmistakeable manner.
For now, I offer a single word:
Rain.

341. robr says:

In the calculations above I typed Ra(Raleigh Number) for Re by mistake..

342. DeWitt Payne says:

Trick,

This violates the 2nd law, KE + PE = constant at each h in the presence of an inexplicable gravity field in the gaseous cv of interest, namely an adiabatic (no gain or loss of heat from CV) GHG-free air column.

That doesn’t look like the Second Law to me. Where’s the entropy term?
Adiabatic expansion ignores conduction, which is a reasonable thing to do in a normal atmosphere. But the atmosphere of a spherical planet with an isothermal surface isn’t normal. There would be no circulation once an adiabatic lapse rate was achieved. At that point, conduction dominates even if it isn’t fast. Conduction is proportional to the temperature gradient. Movement of energy from hot to cold raises the temperature of the cold and decreases the temperature gradient. Eventually, Bart notwithstanding, the temperature gradient approaches zero and the atmosphere becomes effectively isothermal. The entropy of an isothermal atmosphere is higher than for an atmosphere with an adiabatic lapse rate. So the Second Law requires that when work isn’t being done on the atmosphere by circulation between areas on the surface at different temperature (ruled out by the definition of the problem), it becomes isothermal.

343. Hans Jelbring says:

Bryan says:
January 20, 2012 at 10:24 am
Willis says
” To believe that gravity can affect temperature, you have to have a weak grasp of physics, an unshakable belief in your correctness, and a willingness to ignore a bunch of folks who actually understand physics. That’s a bad combo.”
“Yet only last week Willis believed in an adiabatic distribution for a thermally isolated column of gas in a gravitational field.
This week he has ‘seen the light’.
Don’t be so hard on yourself Willis.”
I would for sure want him to get as much insults from the audience here that he has provided to me during this last week and certainly I don´t pitty this clown that tries to be scientific. He can tell where I am wrong in my paper which is common rutin in science or skip the thing. The article is peer reviewed and it stands as it is. And the clown wants an “elevator speach” from me since he “does not understand” what I have written. What comedy.

344. Bill Hunter says:

Willis says:
“IF GRAVITY ACTUALLY SEPARATES TEMPERATURE, WE HAVE FREE ENERGY FOREVER!
If sealed thermally isolated containers of air were to gravitationally separate, with warm air at the bottom and cool air at the top, then we could build tall insulated cylinders and pull power out of them forever.”
Why would the inside of this thermally insulated column of air find a different equilibrium from the equilibrium that existed before you built the containers? Which changes its equilibrium? The air inside the containers or the air outside the containers and why.

345. Phil. says:

Bart says:
January 20, 2012 at 3:35 pm
Bart says:
January 19, 2012 at 11:28 pm
Phil. says:
January 20, 2012 at 1:02 pm
“What it should say is that ‘the heat accumulates in the atmosphere until the layer of gas nearest the surface reaches the surface temperature at which point heat transfer ceases due to ΔT=0.”
The surface temperature is increasing, too. There is no limit on the temperature of the surface, only on radiated energy. If you are not at equlibirum, then you are not generally radiating at the SB limit. That which is not forbidden is compulsory.

You’re dreaming, kindly explain how the temperature of the surface is increasing?
The original post referred to a uniformly heated planet with a transparent atmosphere, the only way that conduction can reduce the radiation loss from the surface is by cooling the surface. If the surface is heating up and still continually losing heat by conduction that’s some bizarre physics you’re proposing!

346. Willis Eschenbach says:
January 20, 2012 at 3:18 pm
Does anyone really, in their heart of hearts, regardless of the logic of any and all arguments, believe that we can constantly and unceasingly pull energy out of a thermally insulated column of air?
Because make no mistake about it. That is what Hans Jelbring is claiming

Gravity != energy
Einstein! Help!

347. Houston, we have a problem. A quick trawl around the net reveals at least five conflicting second laws of thermodynamics.
Science != Settled

348. Hans Jelbring says:

rwemyss says:
January 20, 2012 at 1:29 pm
“@Hans Willis is NOT indicating the heat engine will REMOVE energy from the system! He is indicating that the temperature difference used to run the heat engine can do work on the fluid in the system, and infinitely do so per the theory. Hence the theory fails.”
My paper deals with the properties of ideal gases inclosed in two sperical shells. I don´t know how Willis is going to construct a perpetuum mobile with the aid of ideal gases only since he has never told me. Ask him that.
I have already pointed out that a “perpetuum mobile” is possible to construct in our real atmosphere since the cold air at the top of Mount Everest for sure is colder than air at the surface.

349. Bill Hunter says:

Elevator speech.
An atmosphere currently in motion driven by solar surface radiance and TOA atmosphere radiance. Lots of convection. Seeking equilibrium
Night comes convection greatly slows but does not stop because TOA atmosphere radiance continues.
You also get an inversion layer at the surface due to the surface being a better radiator and cooling the atmosphere some by conduction without the aid of convection but with the aid of residuals of convection, the wind.
Enter Jelbring and and he waves his magic wand and stops the TOA atmosphere radiance to space. He also stops surface interactions with the bottom of the atmosphere or any input or output to the atmosphere.
He is allowed to do this by virtue of basic math where you are allowed to do this conceptually by subtracting equal amounts from both sides of an equation and the laws of thermodynamics specifies incoming must equal outgoing.
Now with nothing to drive it convection rapidly stops probably within hours. The atmosphere is left with a temperature gradient.
So if this is wrong evidence should be given of a force to continue convection without cooling going up or warming going down, or alternatively if it is acknowledged that no force exists to continue convection; where does the energy go or come from to cool the lower atmosphere and warm the upper atmosphere to an isothermal equilibrium.
I am curious about this force. What is it and where does it come from?

350. Hans Jelbring says:

Robert Clemenzi says:
January 20, 2012 at 1:36 pm
” The only way to transfer heat to space is via radiation, and the only way for the atmosphere to loose heat to space is to have greenhouse gases that radiate energy”.
Wrong. Don´t you think that salt particles, droplets (clouds), and dust particles emits IR from the atmosphere. You might also have heard about lightning.

351. sky says:

Certainly gravity does not produce thermal energy per se. But it behooves those who contend that a gravity-bound atmosphere devoid of GHGs would be completely isothermal to explain what then happens to temperature at TOA. Sound physics is not just a simple matter of mathematically pursuing a priori concepts to logical extremes. I’m throwing this on the pile for discussion by others, because I’ll not have any free time next week.

352. Bill Hunter says:

small correction to above elevator speech. The sun stops shining and an inversion layer comes to the cusp of forming when Jelbring waves his magic wand. I want to avoid having a layer actually form and then have to wait for the inversion layer to conduct through the atmosphere which would be a lot more than a few hours.

353. Hans Jelbring says:

Stephen Rasey says:
January 20, 2012 at 2:01 pm
RE: Jelbring at 12:15 pm
“You criticize my use of elevator speech (or verbal proof, take your pick) without addressing its conclusion. You say that there should be two different lapse rates, then go on to say something about equal masses. I never specified equal masses, in fact with two different gasses, with different Cp and probably ….”
The ponit is that an adiabatic lapse rate is equivalent to the statement “that any two arbitrarily choosen equal massues” wihtion the closed sysem will contain equal energy regardless at which altitude they are situated.
I am sorry if I have been unclear in my wording.

354. DeWitt Payne says:

Bart,

But, you have no evidence or citation that it does. SB is always couched in terms of steady state, or at least a quasi-steady state.

You mean besides every textbook in the world about atmospheric radiation? Let’s look at two examples:
Atmospheric Radiation: Theoretical Basis, Goody, R.M. & Yung, Y.L. p31.

Einstein demonstrated that Planck’s source function results if (2.45) [Boltzmann’s law for the distribution of molecules between two states] is obeyed for the levels under consideration. We may, therefore, regard Planck’s and Boltzmann’s laws as interchangeable; conditions leading to one lead to the other and vice versa. We shall go further and demonstrate that a one-to-one relationship exists between the source function and the state populations and, therefore, that our task is simply to calculate the state populations. Now it is known that collisions alone will bring about a Boltzmann distribution and, consequently, a Planck source function.

A First Course in Atmospheric Radiation, Second Edition, Petty, G.W. , p126

For all common applications in atmospheric radiation, Kirchhoff’s Law can be taken as an absolute. It is, therefore, only for the sake of completeness that I point out that Kirchhoff’s only applies to systems in local thermodynamic equilibrium (LTE). This condition applies, for example, when the molecules in a substance exchange energy with each other (e.g., through collisions) much more rapidly than they do with the radiation field or other sources of energy. LTE, and thus Kirchhoff’s Law, breaks down at extremely high altitudes in the atmosphere, where collisions between molecules are rare.

What you have asserted and both references reject is that LTE does not exist for any real object. If LTE did not exist, the the Planck source function would not apply. But you have only asserted this with absolutely no evidence or support. If you were correct, then buying an IR thermometer would be pointless. But you’re wrong and IR thermometers, which use SB, work.

355. Myrrh says:

Stephen Wilde says:
January 20, 2012 at 3:25 pm
Gravity does not separate by temperature. It separates by mass.
This is what I meant, but here said more succinctly..
Jelbring, Nikolov and Zeller (and me) accept that in the absence of an energy source the column will become isothermal.
It is only when energy is added that the temperature gradient forms as a result of more densely packed molecules converting a greater proportion of the incoming radiation to kinetic energy.

But, gravity here is the energy source if pressure is an energy creating heat, if pressure is energy and gravity creates it, then as long as there is gravity, which has different pressures at different heights, then there is a temp differential and if there is a temp differential we get movement, right?.
As colder molecules at the top cool down they will sink, not because they are colder, but because they are now more dense and heavier than the molecules beneath which are hotter, and which being hotter are rising anyway. The pull of gravity now on the denser colder causes them to heat up, there are winds which show this principle, they are also increasing pressure on the warmer beneath which will warm them further/ displace them.
It seems to me that it is only a matter of getting the balance right, the colder top has to be cold enough and at the optimum height re the amount of gravity available not to warm up to a degree that will upset the cooling and sinking as molecules give up their heat to become colder and denser.
Gravity, it seems to me, is as near dammit perpetual motion as long as the optimum conditions can be maintained because it is then a constant force as source of energy, is energy since energy does work – just ‘cos it sits around looking as if its not doing anything…
And I’ve just had a thought, much like those sealed terrariums – the water recycles.
I’ve just had a look to see what I could find on pressure and compression and found this:
“You’ll find an equation used to relate temperature and pressure, which is the 3’rd equation under the heading. Temperature is in absolute (ie: Rankin or Kelvin) and pressure is also absolute, not gage pressure. The exponent n should be 1 for a case where there is so much heat transfer that the air stays at constant temperature, and 1.4 for a case where there is no heat transfer at all. The real case of compressing air in a cylinder by applying a piston and doing work on the air will be somewhere in between because there will be some heat transfer, but not isothermal conditions. ” http://www.physicsforums.com/showthread.php?t=212327
Isn’t that what the force of gravity is doing just by being itself?

356. Hans Jelbring says:

PeterGeorge says:
January 20, 2012 at 3:06 pm
You seem to be religous pretending to be reasoning by a chain of unvalid logic. Please, read the G&T falsification paper or Willian Gilbert on the Tallbloke blog.

357. Bishop says:

Would Jelbring’s theory predict a measurable difference in temperature for a feasible version of the following setup? Take a tube of gas, place a thermometer at the bottom and at the top, place it in a centrifuge with the bottom facing outwards, and spin it up.

358. Myrrh says:

p.s. meant to say Ta, Mods!

359. Fred Allen says:

Willis:
Your initial statement: ‘Consider a gas in a kilometre-tall sealed container.” Assuming a tall, sealed container that is not free to expand, it makes no difference whether it is laid on its side or vertical. The pressure will be the same throughout the container: top to bottom, regardless of gravity. Assuming no outside input and at equilibrium, then according to the equation: P1V1/T1 = P2V2/T2, then the temperature would be the same throughout as well. It cannot possibly be anything else. The pressure at the bottom of the container will be no different to the pressure at the top. In this situation, pressure differential between the inside and outside of the container will increase with vertical height, but the pressure inside the sealed container will not change. So a tall, sealed container might sound reasonable, but cannot be representative of the atmospheric situation. For imaginative purposes, the container needs to be free to expand over its entire length.
Assume the container weighs nothing, contains a portion of atmosphere and is free to expand and contract thoughout its entire length. In this case, the result will look something like a huge weather balloon prior to launch with the dense gas towards the end closest to the gravity source and the expanded end furthest from the gravity. If position 1 is at the lowest end of the bag and position 2 is at the highest end of the bag, then I would assume that without outside input, the reduction of pressure from P1 to P2 would be negated by an equal increase in volume from V1 to V2. There would be no change in temperature…isothermal. In the situation of the sun heating the earth’s surface…well that is a subject for another discussion.

360. Hans Jelbring says:

Myrrh says:
January 20, 2012 at 3:03 pm
And therein lies the problem, that you’re talking about perpetual motion and you don’t know it. Hans, you are indeed proposing perpetual motion. You are saying that gravity separates the warm and cold molecules.
Your lasr sentence is correct. The reason is that maximum entropy or the second law of thermodynamics has to be applied when a gravity field is at work and we are studying a insulated inclosed atmosphere as defined in my E&E paper. Yes, the consequences are tremendous.

361. Hans Jelbring said @ January 20, 2012 at 4:43 pm

If back radiation existed i would be able to go out in the middle of the night and let the radiation hit my face and I would get a nice brown tan in the middle part of winter in northern Sweden when the sun is not shining at all. Even high school kid can figure out that it is impossible. Prefessor Gerlisch has written about this fraud in the G&T falsification of the Greenhouse Effect.
You might know that you quickly get a sun tan in a snowy area since the solar irradiation is coming both directly and is reflected from the snow. Photons works directly from the point they are emitted. If the infamous 390 W/m^2 plus the 330 W/m^2 “downwelling” was real we would get an equivalent to sunshine everwhere regardless if is dark or sunshine. The whole thing is just Alice in the Wonderland Fairtale.

I get my suntan from UV radiation. Where is this fairytale land that enables one to get a suntan from IR radiation? Or are you just saying whatever pops into your head because you know the ignoramuses will believe whatever you say? Sorry if this is rude, but the difference between UV & IR is really basic stuff!
[Mods, you overworked & underpaid paragons of all that is virtuous, this is my third attempt at posting. If the two previous are stuck in the spam filter, please delete them]

362. Hans Jelbring says:

Stephen Wilde says:
January 20, 2012 at 3:25 pm
Gravity does not separate by temperature. It separates by mass.
“Jelbring, Nikolov and Zeller (and me) accept that in the absence of an energy source the column will become isothermal.”
I certainly disagree. The temperature lapse rate will be DALR which is equivalent to equal amount of energy in arbrarily equal masses if the system is insulated.

363. DeWitt Payne says:

Bart,

We don’t consider that in calculating temperature, though. As I pointed out, satellites moving in LEO at 7500 meters per second do not radiate as though they were at 30,000K. A full treatment would need to be couched in terms of relativistic four-momentum, which is always conserved, and for which the time-like element is the energy. I don’t think we really want to get into that, here.

A lone molecule that isn’t colliding with other molecules isn’t in LTE and would most likely be in the ground state so of course it wouldn’t emit. A satellite, if charged, would only emit cyclotron radiation based on its velocity and radial acceleration. That wouldn’t be much because the acceleration is low. The molecules in the atmosphere it collides with. though, is a different matter entirely. Satellites re-entering the atmosphere create temperatures high enough to ionize the air and create a plasma.

364. Hans Jelbring says:

Trick says:
January 20, 2012 at 3:33 pm
Willis says at 1/20 2:19pm:
“I say the column will be isothermal, meaning all at the same temperature top to bottom.”
“This violates the 2nd law, KE + PE = constant at each h in the presence of an inexplicable gravity field in the gaseous cv of interest, namely an adiabatic (no gain or loss of heat from CV) GHG-free air column.”
Many thanks for your insight.
.

365. Trick says:

DeWitt says at 1/20 4:51pm –
“That doesn’t look like the Second Law to me.”
My view is you’re right DeWitt, I’m mixing my metaphors – taking a mechanical conservation of energy knife into a thermo gun fight. My view is employing conservation of energy works here in thermo, I think of 2nd law as conservation of energy. Violating energy conservation whatsoever to create energy collapses a thermo or mechanical issue – especially useful to collapse proposals for perpetual motion machines of the 2nd kind.
DeWitt continues –
“So the Second Law requires that when work isn’t being done on the atmosphere by circulation between areas on the surface at different temperature (ruled out by the definition of the problem), it becomes isothermal.”
This might be true! – & you’re right, ruled out here since it expands the cv of interest to include a surface at different temperature. For the adiabatic GHG-gas column in the presence of gravity, there is no cooler surface exchanging heat with it. That’s where this gun fight might need to go once the simple adiabatic GHG-free gas column in the presence of inexplicable gravity gets general agreement about whether or not it is isothermal (if ever, the age of the universe may come into play). If it does, some agreement will no doubt be grudging, esp. me if isothermal! Then progress discussion to add a surface conducting & radiating heat into the CV with a radiating sink to space.
Turn off the inexplicable gravity in the cv of interest, no pressure stratification occurs and get isothermal PV=nRT everywhere in the gas. KE + 0 = constant everywhere. Turn on inexplicable gravity field and the pesky PE (n*g*h) term inexplicably appears & need to show KE + PE = constant everywhere in the cv or machine of interest.

366. Bart says:

Phil. says:
January 20, 2012 at 5:02 pm
“…the only way that conduction can reduce the radiation loss from the surface is by cooling the surface.”
No, that is not the only way. Stefan-Boltzmann is an equilibrium relationship. You do not know the radiation loss from the surface in non-equilibrium conditions.
You know, it is really annoying when someone proclaims they know everything about a phenomenon which is actively under investigation.

367. Hans Jelbring says:

Bill Hunter says:
January 20, 2012 at 5:20 pm
“I am curious about this force. What is it and where does it come from?”
Let´s say that you inclose and isoöate the atmosphere at an arbirary time when there is wind, lightning, rain tornados etc.
Agree with me that there is a certain total energy inclosed that is constant (1:st law)
Wait a month to see what happens. The second law of thremodynamics will make sure that the entropy get maximised. At that moment the adiabatic temperature has to be -g/Cp.
It is simple!

368. A physicist says:

Fred Allen says: Willis: Your initial statement: ‘Consider a gas in a kilometre-tall sealed container.” Assuming a tall, sealed container that is not free to expand, it makes no difference whether it is laid on its side or vertical. The pressure will be the same throughout the container: top to bottom, regardless of gravity.

With respect, Fred, your starting statement is just plain mistaken.
Ask yourself, what Newtonian force exerts lift upon a helium-filled balloon? Neglecting the weight of the helium (which is far lighter than the air it displaces), the net force on the balloon simply the (lesser) downward force exerted by the lower atmospheric pressure at the top surface of the balloon, relative to the (greater) upward force exerted by the larger atmospheric pressure at the bottom surface of the balloon. After all, what other force is acting upon the balloon?
More generally, what is dismaying about the WUWT posts on this topic is not the errors, but rather the wholly misplaced confidence of many WUWT posters in their erroneous reasoning; a misplaced confidence that dismayingly tends to persist even when serious mistakes in physical reasoning are pointed out.
WUWT has begun to attract criticism in this regard, see for example the scathing editorial Climate Warming Skeptics Ditch the Second Law of Thermodynamics.
It’s time for WUWT folks to accept the possibility — so great as to amount to an plain fact — that “gravito-thermal” theories have just plain got their thermodynamics wrong.

369. DeWitt Payne says:

Bart,

2) Another, equally plausible, scenario is that the system is unstable, such that equilibrium is never attained, even asymptotically. Then, the Stefan Boltzmann relationship does not hold, and there is no limit to surface temperature.

Sorry, it isn’t equally plausible. The surface temperature would be limited by the brightness temperature of the incoming radiation or you violate the Second Law. You don’t get to have high absorptivity and low emissivity at the same wavelength. The only way that a surface couldn’t be in LTE is if the temperature is increasing (or decreasing) extremely rapidly. Not to mention that the original problem in A Matter of Some Gravity stated that the surface of the ‘planet’ was a blackbody.
If it’s plausible, then you should be able to provide examples of solid or liquid materials that don’t obey a Planck source function at 255K and above rather than just postulate their existence.

370. Bart says:

DeWitt Payne says:
January 20, 2012 at 5:34 pm
“…is obeyed for the levels under consideration.”
“For all common applications in atmospheric radiation…”
“But you’re wrong and IR thermometers, which use SB, work [on the Earth in normal conditions].”
So, all of these things hold in a quasi-equlibrium environment. Who’da thunk it?

371. Hans,
I almost fell into the same “the adiabatic lapse rate is the equilibrium condition since it implies the same total energy at any altitude”. Read the discussion below — you should find that the isothermal profile is indeed the correct answer. And you will see that physicists who know thermodynamics well struggle with this question, so it is no wonder that you and I could be misled. (I would love to say I was just playing the devil’s advocate, but I ignored some fundamental thermodynamics and let a too-simple argument cloud my judgement.) Since this is a fundamental assumption of your argument, it invalidates all the rest of your conclusions — sorry about that.
https://carnot.physics.buffalo.edu/archives/2012/1_2012/msg00064.html
This is really not saying anything that has not been said here, but it is more technical/mathematical that the discussions here.

372. Bart says:

DeWitt Payne says:
January 20, 2012 at 5:51 pm
Let’s ditch this line of argument, shall we? Do you deny that there is an upper limit beyond which an atmosphere will boil off, and that your 2nd law objection is therefore inapplicable? If no, then the subject is moot. If yes, then we have reached an impasse.

373. Willy says:

Willis says: “Any random movement of air from above to below a horizontal slice through the container must be matched by an equal amount going the other way.”
It is worth mentioning that since there are more molecules below the slice than above, individual molecules below the slice must be less likely to move up than individual molecules above the slice are likely to move down. Some attempted counter arguments (such as David’s) fail for not taking this aspect into account.

374. DeWitt Payne says:

thepompousgit says:
January 20, 2012 at 4:26 pm

Oddly enough, my understanding of QM came from Feynman’s lectures. Are you saying that he didn’t know what he was talking about? Or are you really Gavin Schmidt putting a different meaning on “understand”?

I was in the class of 1965 at Caltech, so I heard the Feynman lectures first hand. I believe Feynman’s comment applies to understanding the mechanism of quantum mechanics. There is no understanding. It just is.

375. Ultimately, when participating in discussions like this, you have three basic choices.
1) Enjoy it as a rousing debate, where everyone can throw out whatever ideas they want. Listen to the various points — maybe argue for your pet position.
2) Accept the conclusions of those who are the experts. In this case, pretty much everyone with an advanced degree in physics agrees that the isothermal answer is the right answer.
3) Educate yourself so you are yourself an expert. This means actually reading books and/or taking classes and/or sitting down with serious students of the topic. Sometimes the comments here are sufficient to provide that education, but don’t count on random internet posters to provide a free, clear, correct, comprehensive education.

376. Smokey says:

” There is no understanding. It just is.”
So it’s, like, magic?

377. Myrrh says:

Er, not I, Willis said that:
Hans Jelbring says:
January 20, 2012 at 5:45 pm
Myrrh says:
January 20, 2012 at 3:03 pm
And therein lies the problem, that you’re talking about perpetual motion and you don’t know it. Hans, you are indeed proposing perpetual motion. You are saying that gravity separates the warm and cold molecules.
Your lasr sentence is correct. The reason is that maximum entropy or the second law of thermodynamics has to be applied when a gravity field is at work and we are studying a insulated inclosed atmosphere as defined in my E&E paper. Yes, the consequences are tremendous.
======
Sorry, didn’t make it clear – I was quoting Willis and responding to him.
Would you take a read of what I actually wrote in response and tell me what you think? Please don’t use maths.. 😉
http://wattsupwiththat.com/2012/01/19/perpetuum-mobile/#comment-871089
My next post on here: http://wattsupwiththat.com/2012/01/19/perpetuum-mobile/#comment-871204
says: “Gravity, it seems to me, is as near dammit perpetual motion as long as the optimum conditions can be maintained because it is then a constant force as source of energy, is energy since energy does work – just ‘cos it sits around looking as if its not doing anything… “

378. Bart says:

KevinK says:
January 20, 2012 at 4:04 pm
“With all due respect, I am most certainly NOT ignorant of science. With multiple Master’s Degrees in Optics and Electronics and three decades of reconciling computer predictions with actual observations I am quite familiar with all of the relevant disciplines necessary to understand the “Greenhouse Effect”.”
This is really NOT a problem of being smart or dumb. This is an arena in which many misconceptions are deeply embedded and actual data is sparse, leaving smart and able people open to reaching multiple conclusions and interpretations which are not capable of being confirmed or denied.
But, I am afraid you have jumped the gun on this:
“When the energy returns to the surface from the “GHG” you cannot ADD it to the energy arriving from the Sun to produce an alleged “energy budget”.”
Energy is constantly coming in. If some of it is made to hang around longer than instantaneously, before the new batch arrives, then you will accumulate a net offset.
It’s not about increasing energy flow, which is always nearly constant. It’s about impeding that flow so that you keep more close to you.

379. DeWitt Payne says:

Hans Jelbring says:
January 20, 2012 at 4:43 pm

If back radiation existed i would be able to go out in the middle of the night and let the radiation hit my face and I would get a nice brown tan in the middle part of winter in northern Sweden when the sun is not shining at all.

Good luck getting a tan with long wavelength IR. One usually gets a tan from direct normal sunlight which reaches 1000 W/m² total flux with a significant fraction of that in the UV at reasonable elevations above the horizon. But you can point an IR thermometer at the sky at night and get a temperature reading, assuming it isn’t so cold as to be below the lower end of the IR thermometer range. Mine goes down to -60 C, so it has to be really cold and dry to not register. If the sky is clear, the IR thermometer reading will always be lower than the ambient near surface air temperature. With cloud covered sky, it will be about the same.
Or, you could build a box like Roy Spencer and see that while the internal temperature goes below ambient, it would go a lot lower if it were looking at a sky with an effective temperature of 2.7 K. The other advantage of building such a box is that you could also repeat the Wood experiment and prove to yourself that he was wrong. But you would need to paint the inside black rather than white. The other problem is that Roy uses foamed polystyrene. It will likely melt at the temperatures that can be achieved exposed to direct normal sunlight even with a polyethylene film cover. I recommend cardboard coated outside with aluminum foil and baked out in a 120C oven before applying the window and sealing. Otherwise you get condensation on the window. You also need to insulate the walls of the box with six inches (at least) of fiberglass insulation.

380. Trick says:

Smokey says at 1/20 6:32pm:
“So it’s, like, magic?”
LOL, for quantum mechanics, Einstein set the terminology – he didn’t go so far as to say “magic” but was ok with “spooky” action at a distance.

381. Bart says:

DeWitt Payne says:
January 20, 2012 at 6:13 pm
“The surface temperature would be limited by the brightness temperature of the incoming radiation or you violate the Second Law.”
My capacitor analogy is good here. Incoming radiation is the current. Temperature is the voltage. The capacitor accumulates charge continuously, and the voltage climbs continuously.
Does it violate the 2nd law? Yes, if it is an ideal capacitor. Which is precisely why an ideal capacitor cannot exist
Similarly, a non-radiating atmosphere cannot exist. So, if you’re looking for a violation of the 2nd law, it is embedded in the fundamental premise of the problem. But, that does not mean we cannot draw useful conclusions from the thought experiment.

382. DeWitt Payne says:

sky says:
January 20, 2012 at 5:26 pm

Certainly gravity does not produce thermal energy per se. But it behooves those who contend that a gravity-bound atmosphere devoid of GHGs would be completely isothermal to explain what then happens to temperature at TOA.

Umm, it’s the same as the surface temperature. That’s what isothermal means. Of course it depends on what you mean by the TOA. I take it to mean the maximum altitude where the kinetic energy distribution of the molecules is still accurately described by the Boltzmann distribution. That’s going to be on the order of 100 km and includes 99.9999% or so of the total mass of the atmosphere. There’s still some mass left that is gravitationally bound, but when the mean free path is measured in km, the collision frequency is low and LTE doesn’t apply.

383. jae says:

Willis:
“jae, I fear I don’t have a clue which “empirical evidence” you are speaking of. If it has to do with the N&Z hypothesis, I don’t understand the hypothesis so “evidence” means nothing. Let me know which evidence and which theory you’re talking about.
More light and less heat would help here.”
Well, I will assume you are being honest, because you always have been, AFAIK. But…maybe because you get a “headache” when you read Huffman’s stuff (your words, I think), you did not really read his stuff and pay attention to the DATA (aka, EMPIRICAL EVIDENCE!). Same with the other papers. It seems that the atmospheres of other planetoids that have atmospheres have temperatures that are not correlated in any way to the amounts or types of GHGs present in those atmospheres. You continue to ignore all that part of the question, and do not confront it/explain your position. Is it confirmation bias? Old age? Ego? What, Willis?

384. jae says:

AND, Willis, we have the little issue of rapidly increasing GHGs (OCO), but steady or maybe decreasing temperatures for the last few years! Although many other factors are involved, this fact does not help the concept the GHG/heating nonsense and must be annoying, no?

385. Bart says:

DeWitt Payne says:
January 20, 2012 at 6:13 pm
“The only way that a surface couldn’t be in LTE is if the temperature is increasing (or decreasing) extremely rapidly.”
Exponential rise is generally considered “extremely rapid”. What would the exponent be? What would you expect the heat capacity of a non-radiating material to be?

386. ferd berple says:

Bill Hunter says:
January 20, 2012 at 5:01 pm
Willis says:
“IF GRAVITY ACTUALLY SEPARATES TEMPERATURE, WE HAVE FREE ENERGY FOREVER!
If sealed thermally isolated containers of air were to gravitationally separate, with warm air at the bottom and cool air at the top, then we could build tall insulated cylinders and pull power out of them forever.”
Apparently you’ve never heard of OTEC.
http://en.wikipedia.org/wiki/Ocean_thermal_energy_conversion

387. ferd berple says:

Willis says:
“IF GRAVITY ACTUALLY SEPARATES TEMPERATURE, WE HAVE FREE ENERGY FOREVER!
Why do you think the oceans are colder on the bottom and hotter on the top? Gravity separates the oceans by temperature.
However, water is incompressible, which explains why the oceans are colder at the bottom. Water can only change density as a result of temperature. Air on the other hand changes density in response to both temperature and altitude.

388. KevinK says:

For Davidmhoffer, if you liked my shorter analysis this longer analysis may be of interest to you;
The CRITICAL flaw in the “Greenhouse Gas” hypothesis….
Lots of attention has been given to the alleged “Greenhouse Effect” over the last few decades. It seems an elegant hypothesis that can explain almost every weather effect that occurs (i.e. droughts, floods, blizzards, warm spells, cold spells, more arctic ice, less arctic ice, shrinking glaciers, etc.)
However this hypothesis has a CRITICAL flaw.
Please allow me to me explain…
In any proper analysis of energy flow through a complex system it is necessary to stop occasionally to perform a “sanity check”, this indispensable tool is applied by engineering professionals to ascertain if our predictions/calculations still make sense in regard to the system we are analyzing/designing.
So let’s do a simple sanity check on the “Greenhouse Effect” (moving forward this will be abbreviated as the “GHE” for simplicity).
To quickly summarize the GHE;
1) Visible light (aka EMR radiation) is absorbed by the surface of the Earth
2) The warmed surface of the Earth emits Long Wave Infrared (LWIR) light
3) This LWIR is absorbed by gases in the atmosphere
4) These “warmed” gases emit energy back towards the surface of the Earth
5) And THEREFORE the “GHGs” cause the surface of the Earth to acquire a higher “equilibrium” temperature
I hope I have captured the essential essence of the GHE with this short summary. Of course, I fully expect some folks to disagree and inform me that I have misunderstood the GHE. So be it, we will deal with that at a future time.
To describe the flaw in the GHE we first need to conceptualize a convenient bundle of energy that we can follow through the Sun/Earth/Atmosphere/Universe system. This bundle of energy needs to be large enough so we can (largely) ignore effects that happen at the atomic level. Also the bundle needs to be small enough so we can track it in a “real time” fashion and determine what happens to the energy.
For the purposes of this discussion I propose we use 1 milliJoule of energy. This is 1 one-thousandth of a Joule. This should be just the right size for my purpose of demonstrating the flaw in the GHE hypothesis.
So let’s get to it, here is the sequence of events involved in the GHE;
1) A bundle (1 mJ) of energy in the form of mostly visible light arrives at a specific location on the Earth’s surface, courtesy of our friendly neighbor the Sun.
2) Some portion of the bundle is immediately reflected and departs at the speed of light in an opposing direction. I won’t bother to get into an interminable discussion of what the Albedo is since this proof does not require this knowledge. In fact it could be any number above zero and less than or equal to 1 without making any difference.
3) The remaining portion of the bundle is absorbed by the surface and converted to heat, this is the FIRST warming event (Warming Event #1) caused by our little bundle of energy. And if we know what material (sea water, soil, etc.) absorbs the bundle we can make a pretty good estimate of the temperature increase, but that calculation is not necessary.
4) Now, several things will happen to this bundle of thermal energy;
a) It can be conducted to locations below (or adjacent to) the surface which are colder.
b) It can be conducted to a stationary gas molecule in contact with the surface.
c) It can be convected away by a moving gas molecule that happens to contact the surface while travelling past.
d) It can be radiated as Infrared Radiation away from the surface.
It is important to note that in most cases all four of these events will happen in parallel (i.e. at the same time), so the actual Portion Radiated can vary from 0% to 100%.
5) No matter what happens in step 4, the surface cools (Cooling Event #1) by an amount which corresponds to the loss of of energy at that location. The amount radiated is somewhere between 0% and 100% (Albedo * Portion Radiated) leaving our radiated bundle at somewhere between 0 and 1 mJ. Again, if we wanted to calculate the temperature drop associated with the cooling we could use the thermal capacity of the material to make an estimate. It is important to note at this time that this absorption/remission process IS NOT instantaneous; it requires a finite amount of time (Time Delay #1) that is greater than zero.
6) The radiated energy (something between 0 and 1 mJ) now travels away from the surface at something close to the speed of light. Note that there are a few “flavors” of the speed of light depending on the material our little bundle is travelling through. The fastest flavor is when the light is travelling through a vacuum. When moving through the lower atmosphere the speed is slightly slower.
7) Our little bundle, speeding happily along and accelerating as the atmosphere gets less dense MAY be absorbed by a GHG. Whoops, that’s inopportune; it was hoping to get to Alpha Centuri before next Tuesday to watch the REAL Miss Universe show (ok a lame joke). The important thing to note is that a finite amount of time (Time Delay #2) has elapsed before the absorption occurs.
8) Once our bundle of energy is absorbed by the GHG it ceases to exist as IR light and is converted to heat (Warming Event #2). This is our little bundle’s second warming event within a few milliseconds, boy am I proud. Note that with any flavor of the speed of light our bundle can make it to the top of the atmosphere (TOA) in a few milliseconds at most.
9) Now, of course the same possibilities shown in step #4 may happen at the GHG molecule. Again all four of the possibilities can occur. To speed up this discussion we will assume that 100% of the energy is emitted as IR radiation. So the best case (or worst case if you still believe in the GHE) is that all of our 1 mJ has arrived at the GHG molecule and is going to be radiated away. A couple of important points need to be made here, first something less than 50% of our bundle can hope to head back towards the surface (as fixed by the geometry of a sphere). And secondly there is some finite time delay involved in the absorption/remission event (Time Delay #3).
10) Once the bundle of energy has been radiated by the GHG molecule the molecule will cool (Cooling Event #2) by an amount commensurate with the energy reradiated. And we could, if we wished, estimate the temperature drop, but it is immaterial.
11) Once again our little bundle is happily speeding along at the speed of light, but slowing down this time as the atmosphere gets denser. Oh well, zipping along at any flavor of the speed of light still beats a Lamborghini. And of course our little bundle is now no more than half of the man (or woman) that it used to be.
12) Damn, we flew our bundle right down into the ground (after Time Delay #4); I hate it when that happens. But the good news is we now have GHE induced warming (Warming Event #3). We could again have the Albedo argument (in the IR portion of the spectrum this time), but it does not matter. The IR radiation has ceased to exist and is now heat. So this takes us full circle and we are back at step #3, EXCEPT, AND THIS IS A REALLY BIG EXCEPT STATEMENT, two subsequent warming and two subsequent cooling events with four time delays interspersed have also taken place in the meantime. TO SUM THE FIRST WARMING EVENT WITH THE THIRD WARMING EVENT (both of which happen at the Earth’s surface) CLEARLY VIOLATES THE FIRST LAW OF THERMODYNAMICS. THE GHE DOES NOT AND CANNOT CAUSE ANY “HIGHER EQUILIBRIUM” TEMPERATURE TO EXIST AT THE SURFACE OF THE EARTH (or anyplace else for that matter).
13) You are free to expand this time series to describe the third, fourth, fifth, etc, etc. sequential warming/cooling events if you wish, but I am extremely proud of my little bundle at this point and do not see the need. It should be noted that as one bundle of energy is absorbed/reemitted multiple times the amount reaching the surface declines as follows, 50%, 25%, 12.5%, 6.25%, 3.125%, 1.5625%, 0.78125%, 0.390625%, 0.1953125%, 0.09765625%. So after as few as ten bounces (taking at maximum perhaps 40 milliseconds if the energy makes it all the way to the TOA) the energy is already less than 1/10 of 1 percent of the initial amount.
I know lots of folks will disparage this discussion. So I will suggest a few FAQs in advance;
1) Q: But, but, but… all the other proud energy bundle parents are sending theirs out to do the same thing, so surely the volume of little bundles will make the GHE occur.
A: NO, all of the little bundles are travelling in parallel and do not sum. If we cannot demonstrate how one bundle of energy can make the GHE real, then we cannot claim that the GHE exists when discussing a “higher equilibrium” temperature
2) Q: But, but, but… the time delays you suggest are so long that energy is left over at the end of each day, and this is really what the GHE is about.
A: NO, at the speed of light each bundle could make 10 round trips to TOA and back to the surface in less than about 40 milliseconds. For reference, each day contains about 86 million milliseconds. So no energy is left over at the end of each day. Besides if energy was left over the Earth would slowly heat up 1 little notch at the end of each day and would have melted a long time ago (ignoring for a moment the fact that as the surface warms the emission spectrum shifts to lower (i.e. more transparent) wavelengths).
3) Q: But, but, but… you assumed the wrong value for the Albedo, Lapse Rate, Amount of
GHGs present, etc. etc. etc.
A: NO, this discussion is about the fact that sequential warming and cooling events occur with finite time delays (more than zero, but otherwise undefined) between each event and the events have finite (greater than zero and less than or equal to one) probabilities of occurrence and therefore CANNOT be summed to yield a “higher equilibrium” temperature.
4) Q: But, but, but… you have not presented any explanation about how the surface of the Earth reaches its average temperature without the GHE.
A: Agreed, I have not yet presented any theories about why the temperature of the Earth is what it is. So here I will;
First, I believe that the application of the Stephan-Boltzmann equation in conjunction with the
Kirchhoff radiative equilibrium equation have been performed incorrectly. Yes, I realize that’s a big deal because it’s written in all the climate science textbooks, so IT MUST BE SO. Well, if we never revised textbooks we would be in a bunch of hurt. Just because it is written down in a 20 year old book does not necessarily make it so. And a computer model that implements the assumptions of a hypothesis IS NOT a proof of the hypothesis, regardless of how fast the computer can collide numbers together.
Second, I suggest that the average temperature of the Earth is determined by the massive thermal capacity of the Oceans and the amount of energy already deposited there (by some undefined prior event(s)). Clearly, the Oceans do not respond to changes in the energy arriving at the surface on a time period of days, or even hundreds of years. A good analogy (as an electrical engineer I must mention this) would be the battery that you (likely) use to start your internal combustion car each day. It has a bunch of energy stored inside (provided by the manufacturer). Each day when you start your car you suck a whole bunch of energy out of it. Then you slowly recharge it (with the alternator) while you drive. So it always has a bunch of energy present, we are missing the fact that the manufacturer filled it up before you bought it. Just like the Ocean was already “charged up” before we invented the GHE.
5) Q: But, but, but… you are ignoring all the “evidence” of climate change, the shrinking glaciers, the floods, the droughts, the heat waves, etc. etc….
A: Two Words; CONFIRMATION BIAS. And unlike our current Vice President, I can in fact perform a simple task like counting the number of words in my statements.
6) Q: But, but, but… you are not a climate scientist that has peer reviewed publications, so we should not listen to you.
A: Yes, I am not a climate scientist with peer reviewed publications. This is in fact a situation I take some pride in. This discussion relies on a simple flow of logic. Read it at your own risk. Find the flaws. Point them out. Be skeptical.
In summary, the critical flaw in the GHE hypothesis is that the warming from GHGs happens sequentially AFTER a previous cooling event WITH an intervening time delay, THUS it cannot be added to the initial warming event. And therefore the GHE does not create “extra energy” or “net energy gains”.
Further, these warming and subsequent cooling events happen so quickly that the GHE has nothing to do with the “equilibrium” temperature present at the surface of the Earth.
Further, the warming from the GHE dissipates so quickly that it cannot be reasonably expected to influence the massive thermal capacity of the Oceans in any way.
Cheers, Kevin.

389. Joel Shore says:

thepompousgit says (in response to Hans Jelbring):

I get my suntan from UV radiation. Where is this fairytale land that enables one to get a suntan from IR radiation? Or are you just saying whatever pops into your head because you know the ignoramuses will believe whatever you say? Sorry if this is rude, but the difference between UV & IR is really basic stuff!

Yeah…The way I was going to put it is that infrared radiation doesn’t give you a sun tan for the same reason that cell phones don’t give you brain cancer: The energy of the photons are way too small to cause this sort of cell damage to occur.
Einstein figured this out about a century ago.
pochas says:

I think this thread has jumped the shark.

This may well be the understatement of the century!

390. ferd berple says:

Willis says:
“IF GRAVITY ACTUALLY SEPARATES TEMPERATURE, WE HAVE FREE ENERGY FOREVER!
Consider ice. Ice is colder than liquid water, yet unlike liquid water, ice floats to the top (because of gravity). Liquid water on the other hand sinks when it gets colder. Again due to gravity.
Ice shows that density work together with gravity to separate the oceans by temperature.

391. Bill Hunter says:

Almost by definition I am the guy for which an elevator speech is supposed to be comprehensible.
I may be asking some bizarre stuff but if somebody doesn’t start answering them I would have to think that there is no hope or desire by anybody to come up with an elevator speech.
So that said here is one more. I have been led to believe 2 things.
1) the adiabatic convention process does not change the kinetic energy of a molecule of gas but does change the temperature. Though kinetic energy might change via radiation to space or to another molecule that lost some of its energy to space.
2) My reading on thermopiles is they do not respond to absolute temperature but instead gradients represented by kinetic energy differences (e.g. frequently also temperature gradients).
Are these substantially correct facts?

392. DeWitt Payne said @ January 20, 2012 at 6:21 pm

I was in the class of 1965 at Caltech, so I heard the Feynman lectures first hand. I believe Feynman’s comment applies to understanding the mechanism of quantum mechanics. There is no understanding. It just is.

De Witt, I envy you. Nothing to disagree with when you use the modifier. Did you by any chance attend the lectures on the derivation of Newton’s Laws from conic sections? They are my favourite…

393. KevinK says:

Bart wrote;
“Energy is constantly coming in. If some of it is made to hang around longer than instantaneously, before the new batch arrives, then you will accumulate a net offset.”
Bart, have you ever taken any classes in the analysis of AC (alternating current) circuits ? I am very serious in this question.
If you have determined a means to effect a DC (direct current) “offset” by changing the response time of an electrical circuit you are quite a bit ahead of those that do electrical circuit design for a living. We can do this but we use diodes (aka rectifiers) to accomplish this task. the GHE does not behave as a rectifier does (i.e. energy only flows one way).
I suggest you study electrical engineering a bit before you discuss “offsets”, it is quite a BIG topic in our field.
Cheers, Kevin.

394. markx says:

(To Moderators: Very Sorry – previous post unfinished and held a contradictory statement – please use this one) [Done -w.]
Taking the most simplistic approach possible:
A uniformly irradiated world, no rotation, no poles, two gas atmosphere (no water/condensation)
Atmosphere is uniformly dense – no pressure gradient:
Assuming there is only 1 GHG gas present in trace amounts and only that GHG can absorb IR energy. Assuming the ‘one other gas’ TG is totally transparent to all incoming and outgoing radiation.
Assuming all energy absorbed by the surface from the sun is then emitted at one IR wavelength which is only (and totally absorbed) by the one GHG gas.
Assuming all IR energy (100%) is absorbed by that GHG in the first 10 meters above the surface.
Assuming that energy is transferred rapidly by collision to TG molecules near the surface.
Assuming it is largely the TG molecules which carry the energy to the upper atmosphere by convection.
Assuming the energy can only be emitted to space by being passed back to a GHG in the upper atmosphere.
Case 1 Double the quantity of GHG, energy is totally absorbed and passed to TG twice as rapidly. After the system equilibrates there is a trace amount of extra energy retained in the atmosphere at any point in time. (related to that held by the extra GHG molecules).
There are now twice as many GHG molecules in the upper atmosphere with the opportunity to emit energy to space, but there is also twice as much opportunity they will intercept each-others’ IR emissions – average emission to space remains the same, and atmospheric temperature remains (almost) the same.
Case 2 Double the quantity of TG, retaining the original level of GHG There is twice the opportunity of collision between GGH and TG at all levels of atmosphere , energy near the surface is transferred more quickly to the TG. The atmosphere can now retain twice the energy of the original world. In the upper atmosphere there is twice the opportunity to pass the energy from the TG to the emitting GHG. Emission rate in the upper atmosphere is dependent on the opportunity of the GHG to collect some energy (now doubled), and the density of GHG at altitude (only another GHG molecules can intercept the transfer of IR energy to space). As GHG density at the upper atmosphere is still the same, emission rate should double (Twice the opportunity to collect energy, but retaining the original opportunity to emit to space.)
The lower atmosphere at equilibrium retains twice the energy of the original world. The upper atmosphere emits it twice as quickly. What effect does this have on atmospheric (and surface) temperature?
Repeat the exercise with graduated layers of from greater to lesser density atmosphere. Do the effects remain the same layer by layer?

395. Bart says:

KevinK says:
January 20, 2012 at 7:28 pm
“I suggest you study electrical engineering a bit before you discuss “offsets”, it is quite a BIG topic in our field.”
Maybe you need to review laser cavities a little.

396. Bart says:

KevinK says:
January 20, 2012 at 7:28 pm
“We can do this but we use diodes (aka rectifiers) to accomplish this task. the GHE does not behave as a rectifier does (i.e. energy only flows one way).”
Actually, that is exactly what is happening, so this might help you comprehend. The energy comes in shortwave. It goes out longwave. So-called GHGs are transparent to shortwave, opaque to longwave.

397. Bart says:

KevinK says:
January 20, 2012 at 7:28 pm
For the other people with whom I have been discussing my hypothesis of “GHG” cooling: Anyway, that’s the standard greenhouse argument. I am not saying GHGs necessarily cause the ground to heat more than it would otherwise. But, what they are doing has the same steady state effect as if they were, and the interpretation in the steady state is merely ambiguous. Kevin has simply gone off the rails, and I am trying to help him understand the GHG argument, and that he has done nothing to refute it.

398. KevinK says:

Ok, I now declare this an OFFICIAL FARCE…….
We clearly have two camps, the believers in the GHE and those that have sound technical reasons to DOUBT it.
I suggest we all shovel the snow from our driveways and reconvene next summer to discuss it again……………..
Cheers, Kevin (see you after the thaw)

399. KevinK;
Well said. May I offer a simple analogy and then launch into an extension of your explanation that ties back to N&Z? Thanks!
Analogy:
I dam a river and form a lake. At equilibrium, the river flowing in has a flow rate of 240 m3/min. Outflow at the dam = 240 m3/min. I raise the dam one meter. After a short period of time, the flow rate in is… 240 m3/min and the outflow is 240 m3/min. The depth of the water increases by 1 meter, and the potential energy stored as a consequence of that can be calculated, but the flow rate at equilibrium changes not one bit. The same is true of doubling C02. Temporary fluctuation in the system, but one equilibrium is established again, the incoming w/m2 and the outgoing w/m2 are exactly what they were before. There’s been an increase in heat stored in the system, but in terms of the average w/m2 exiting the system as a whole, they are exactly the same as they were before down to the last watt. Since everyone wants to average w/m2 and convert that to degrees, I say let ’em. If they cannot show that the incoming watts absorbed has changed, then at equilibrium the outgoing watts have to be the same too. Since the outgoing watts are the same, temperature of the planet is the same. Go ahead folks, use SB Law to contradict that.
Onto N&Z building on what KevinK explained.
Imagine that there are upward bound photons being released from earth surface and from every layer of the atmosphere at every elevation. Some escape, and some don’t. The most photons emerge from the earth surface, BUT… they have the smallest chance of getting out to space because they have the greatest chance of being absorbed on the way up. As we increase in altitude, there are less upward bound photons released from a given layer because a) the temperature is lower and b) the density is lower. BUT…the percentage chance that any upward bound photon will escape to space increases with altitude. Let’s repeat that. The higher the altitude, the greater the percentage chance that any given upward bound photon will escape to space is.
As KevinK explained, once you hit equilibrium, every photon rising from earth surface cools the surface. If it is intercepted somewhere in the atmosphere, then that spot in the atmosphere warms. If the photon is re-emitted, then that spot in the atmosphere cools. If the photon goes downward, it must inevitably be absorbed again, either in the atmosphere or the earth surface, and where ever that happens, that spot warms and re-emitts. At some point though, the photon escapes, taking with it the exact same amount of energy as it brought when it entered the system. The net is zero.
So…as seen from space, let us assume we can “see” an average (ignorant term and wrong but for sake of argument I’ll live with it for this example) we can “see” 240 w/m2 exiting the system. How many watts came from where? Some of the photons would in fact be emitted from earth surface and go straight to space uninterrupted. How many? Not many. Even though the most upward bound photons in the system are being released from the warmest surface (earth surface) not many escape. The frigid TOA though is pouring the photons into space. It might be cold at TOA, but every upward bound photon emitted at TOA has a 100% chance of escaping to space.
Hence….
The greater the mass of the atmosphere, the lower the chance of any energy packet escaping to space. At earth surface, conduction and convection will massively dominate radiance, and photons released via radiance have a near zero chance of escaping directly to space anyway. At high elevations, while the temperature is must lower than earth surface, conduction and convection are vastly reduced. While the number of photons is also vastly reduced due to the lower temperature, the percentage chance that any given one of them will escape is vastly higher.
Hence…
The greater the mass of the atmosphere, the greater the surface pressure and the greater the dominance of conduction and convection and the less impact on temperature of radiance. The greater the mass of the atmosphere, the more skewed the ratio of photons released at high altitudes will be. And if one “averages” the upward bound flux that actually escapes to space from earth surface to TOA, what will one get?
One will get exactly the total flux being absorbed.
If 240 w/m2 is being absorbed, then 240 w/m2 is existing. The greater the mass of the atmosphere, the more likely that any given energy packet will be returned from the surface straight back to the surface, and thus the higher the surface temperature. The greater the atmospheric mass (and hence surface pressure) the more skewed to higher (colder) altitudes the percentage of escaping photons will be. BUT… the average will always equal exactly the mount being absorbed.
Hence, as per N&Z…
The greater the mass of the atmosphere, the higher the surface pressure and so the higher the surface temperature. Calculate insolation absorbed, and you now have two variables, insolation and surface pressure, that define the surface temperature. Double or quintuple CO2 and you know how much the surface temperature changes? It changes by the amount that the mass of the atmopshere (and hence surface pressure) changes. But the incoming and outgoing watts remain (at equilibrium) unchanged.
Just like the water going over the dam.
Dammit

400. Myrrh says:

Myrrh says:
January 20, 2012 at 5:38 pm
Stephen Wilde says:
January 20, 2012 at 3:25 pm
Gravity does not separate by temperature. It separates by mass.
This is what I meant, but here said more succinctly..
======
er.., I meant weight…
http://www.exploratorium.edu/ronh/weight/

401. jae says:

“jae says:
January 19, 2012 at 7:05 pm
DAMMIT, WILLIS:
PLEASE ADDRESS THE EMPIRICAL EVIDENCE, WHICH WILL ULTIMATELY RESOLVE THIS ARGUMENT! WHY DO YOU REFUSE TO DO THIS?
[Moderator’s suggestion: If you didn’t YELL at him maybe more would be accomplished? Maybe? -REP]”
It seems that some of Anthony’s “moderators” need some moderation. Is it really the moderator’s place to tell me just how to express myself on a blog? I think NOT! Just what the hell do you think you are?

402. DeWitt Payne says:

Bart says:
January 20, 2012 at 6:17 pm

DeWitt Payne says:
January 20, 2012 at 5:51 pm
Let’s ditch this line of argument, shall we? Do you deny that there is an upper limit beyond which an atmosphere will boil off, and that your 2nd law objection is therefore inapplicable? If no, then the subject is moot. If yes, then we have reached an impasse.

Of course there’s an upper limit, but there’s not very much mass between that level, where the atmosphere consists almost entirely of hydrogen and helium, and the level where LTE applies, which would be isothermal at the surface temperature under the conditions specified by Willis in his original Gravity post.
Out of curiosity I calculated the pressure a function of altitude for a purely adiabatic atmosphere. For a surface temperature of 255K, it would reach a pressure of zero and a temperature of 0K at an altitude of about 26.2 km. But there’s no way it would stay that way as the thermal diffusivity gets quite large as the pressure goes to zero.

403. Bill Hunter says:

ferd berple says:
January 20, 2012 at 7:12 pm
“Why do you think the oceans are colder on the bottom and hotter on the top? Gravity separates the oceans by temperature.”
Yes, but only accounts for a small portion of the temperature gradient in the upper ocean.

404. Joel Shore says:

KevinK says:

In any proper analysis of energy flow through a complex system it is necessary to stop occasionally to perform a “sanity check”, this indispensable tool is applied by engineering professionals to ascertain if our predictions/calculations still make sense in regard to the system we are analyzing/designing.

Speaking of sanity check, you may want to try one on your argument. For example, can you extend it to show that there’s no advantage to wearing a jacket when you go out on the cold or putting any insulation in the attic of your house? (Basically any case where you have the steady-state temperature of an object determined by the balance of what energy receives and what energy emits.)
It is amazing how difficult basic concepts become for people, even “engineering professionals” when the concepts conflict with what they strongly want to be the case!

405. DeWitt Payne says:

Bart says:
January 20, 2012 at 6:50 pm

Similarly, a non-radiating atmosphere cannot exist. So, if you’re looking for a violation of the 2nd law, it is embedded in the fundamental premise of the problem. But, that does not mean we cannot draw useful conclusions from the thought experiment.

What useful conclusions can be drawn? A surface that can absorb radiation but not emit it at any wavelength at any temperature while having zero heat capacity goes far beyond postulating a perfectly transparent atmosphere or a surface with an absorptivity identically equal to 1 as limiting cases in thought experiments. It’s so far removed from reality as to be worthy of the term unphysical and the results are completely irrelevant to anything real. It says nothing whatsoever about the atmospheric greenhouse effect on a real planet. Especially it does not say that addition of greenhouse gases cause the surface of a rotating spherical planet with an IR absorbing atmosphere in orbit around a single star to cool compared to an atmosphere that is more transparent in the IR.

406. gbaikie says:

“Taking the most simplistic approach possible:
A uniformly irradiated world, no rotation, no poles, two gas atmosphere (no water/condensation)
Atmosphere is uniformly dense – no pressure gradient:
Assuming there is only 1 GHG gas present in trace amounts and only that GHG can absorb IR energy. Assuming the ‘one other gas’ TG is totally transparent to all incoming and outgoing radiation.
Assuming all energy absorbed by the surface from the sun is then emitted at one IR wavelength which is only (and totally absorbed) by the one GHG gas
Assuming all IR energy (100%) is absorbed by that GHG in the first 10 meters above the surface.”
Let’s stop here.
Let’s look at this world. Unless one can see this IR energy [humans without devices can’t], from space this planet would be utterly black.
Next problem is nothing absorbs all the sun’s radiation.
If we assume you mean that a limited amount of the sun’s radiation is absorbed and have the rest reflecting, we fix the problem of having a utterly black world and it’s conceivable that the GHG is absorbing this limited band width. It’s quite simple actually, you have CO2 ocean and a CO2 GHG gas. The CO2 ocean only absorbs and emits what the CO2 gas can absorb and emit.
Venus is almost this- but Venus ocean is not a liquid, but instead it’s a hot dense gas. Though don’t think matters whether it’s gas or liquid. On Venus visible light reaches the surface but we can assume any wavelength the sun emits which CO2 can absorb isn’t shining from the sun to the surface- it’s being absorbed and emitted by the CO2. The CO2 is not a “surface” [liquid or solid] but what difference does it make?
So it seems you are basically talking about Venus. If you don’t mean the planet is utterly dark from space [or on the planet].
Continuing:
“Assuming that energy is transferred rapidly be collision to TG molecules near the surface
Assuming it is largely the TG molecules which carry the energy to the upper atmosphere by convection
Assuming the energy can only be emitted to space by being passed back to a GHG in the upper atmosphere”
Again still Venus. Though difference is CO2 not trace gas, and TG is actually minor constituent
of atmosphere [around 3% but that is about 3 earth atmospheres of N2- so a lot of N2 but dwarf by massive amount of CO2]
“Double the quantity of GHG, energy is totally absorbed and passed to TG twice as rapidly.
After the system equilibrates there is a trace amount of extra energy retained in the atmosphere at any point in time. ”
We could 1/2 the amount of CO2 on Venus and thereby double the amount of N2 relative to the CO2:)
I think Venus would cool if lost half it’s CO2.
But replaced the half of CO2 with same amount of
N2- took out 46 atm of CO2 and replaced with 46 atm of N2, then I would suppose that the Venus surface would become much dimmer- not allowing as much diffused sunlight from reaching the surface. But don’t think that would change the planet’s temperature.
“(related to that held by the extra GHG molecules).
There are now twice as many GHG molecules in the upper atmosphere with the opportunity to emit energy to space, but there is also twice as much opportunity they will intercept each-others IR emission – average emission to space remains the same, and atmospheric temperature remains the same.
“Double the quantity of TG. There is twice the opportunity of collision between GGH and TG at all levels of atmosphere, energy near the surface is transferred more quickly to the TG.”
As said don’t think there would any difference.
Move Venus to earth orbit and Venus would change quite significantly- though require a long time to radiate the energy- so could a million years to change significantly.
“Repeat the exercise with graduated layers of from greater to lesser density atmosphere. Do the effects remain the same layer by layer?”
As saying above, if you half the amount CO2 in the atmosphere, made a 46 atm instead of 92 atm, this would radically change the temperature- lower by say 100 K. Half it again, and I would guess the temperature would lower again significantly and because Venus does not rotate, one could get liquid CO2 on nite side and cascading lowering of atmosphere pressure, and further lowering of temperature. Or have similar effect of moving Venus out to Earth orbit.
Venus would develop very small ocean of liquid CO2- possibly seeping under ground or making lakes in lowest elevations.

407. DeWitt Payne says:

thepompousgit says:
January 20, 2012 at 7:28 pm

Did you by any chance attend the lectures on the derivation of Newton’s Laws from conic sections? They are my favourite…

He did that (those) lecture(s) after I graduated, as I remember. I do have a copy on CD of the lecture on deriving the 1/r² force relationship from Kepler’s Laws, though. It’s too bad there weren’t pictures of the blackboards he used. Newton used conic sections. Feynman used a more readily comprehensible geometric approach. As I remember, Feynman did it that way because he couldn’t follow Newton’s proof. Conic sections were big in Newton’s day.

408. Myrrh says:

Cheers, Kevin.
Joel Shore says:
January 20, 2012 at 7:15 pm
thepompousgit says (in response to Hans Jelbring):
I get my suntan from UV radiation. Where is this fairytale land that enables one to get a suntan from IR radiation? Or are you just saying whatever pops into your head because you know the ignoramuses will believe whatever you say? Sorry if this is rude, but the difference between UV & IR is really basic stuff!
Yeah…The way I was going to put it is that infrared radiation doesn’t give you a sun tan for the same reason that cell phones don’t give you brain cancer: The energy of the photons are way too small to cause this sort of cell damage to occur.
Einstein figured this out about a century ago.
=============
Go out in the midday sun in the tropics, photon for photon UV won’t be able to penetrate further than the epidermis, the first layer of skin, to give you a tan while thermal infrared, heat, will penetrate some inches and its energy absorbed by the water in you, you’re mostly that and water is the great absorber of heat, will move the water into vibration, kinetic energy, heat. UV will damage you from the outside in and you won’t know it’s happening until you can feel the effects; thermal infrared, if you’re unable to sweat it out, will boil you from the inside out. You’ll boil quicker than you’ll get skin damaged to death… Put on a shirt, you stop UV in its tracks, no suntan, that’s how strong an energy it is.. it’s tiny, really tiny, compared with thermal infrared.
UV doesn’t give you a tan because it burns you, you can’t feel UV, it doesn’t burn you, it gives you a tan because the melanin in your body is doing its best to neutralise excess of it scrambling your skin on a DNA level. It is essential for the production of vitamin D. Thermal ir is bigger and packs more punch, stand in front of a fire, that’s thermal ir you can feel burning you directly. Compare with sunbed.
There’s a world of difference between UV photo-damage and thermal infrared heat damage.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2671032/
Thermal infrared is the size of a pin head, near ir is microscopic, how big is UV compared with them?

409. gbaikie says:

“8) Once our bundle of energy is absorbed by the GHG it ceases to exist as IR light and is converted to heat (Warming Event #2). This is our little bundle’s second warming event within a few milliseconds, boy am I proud. Note that with any flavor of the speed of light our bundle can make it to the top of the atmosphere (TOA) in a few milliseconds at most. ”
What is meant by warming event. Has the GHG gas molecule velocity increased, or is it excited molecule which may soon emit the same wavelength or same different wavelength that it is capable of emitting.

410. Jim D says:

The isentropic state is the state of maximum entropy. If you start with an isothermal atmosphere and thoroughly mix it without adding energy, you end up with an isentropic state which has the adiabatic lapse rate. Once in this state, the air can’t be unmixed (because entropy is maximized), so in this sense it is a final state for a given energy content. This doesn’t mean that an isothermal state or any stable lapse rate cannot last an infinite amount of time. I don’t think the problem is well posed because many states can last infinitely long if only diffusion is acting, but only the isentropic state cannot be transformed to another state by mixing, in my opinion.

411. DeWitt Payne says:

gbaikie says:
January 20, 2012 at 8:47 pm
I’ve actually run some numbers on Venus using the line-by-line program at spectralcalc.com . They have a database of high pressure CO2 absorption lines. Because the surface temperature is so much higher, the 15 μm band of CO2 doesn’t contribute much. Even at 92 bar, there are still ranges of relatively low absorption for CO2 alone. However, those gaps are nearly filled by SO2 and H2O, even though the partial pressure of H2O is small. Replacing half the CO2 with nitrogen does cool the surface, but not by much. Another interesting point is that it isn’t completely dark in the visible spectrum at the surface when the sun is above the horizon. One of the Russian probes that made it to the surface managed to transmit some visible light photographs before it failed. You do have to lower the total pressure to get major a major reduction in temperature. We had a big discussion of this over at scienceofdoom.com .

412. Joel Shore;
Speaking of sanity check, you may want to try one on your argument. For example, can you extend it to show that there’s no advantage to wearing a jacket when you go out on the cold or putting any insulation in the attic of your house? >>>
Good lord man, what brand of cereal did your physics degree come in anyway? The person wearing the jacket and the home with the attic both have INTERNAL heat sources. The increased layers of insulation change the temperature gradient such that is is more pronounced closer to the heat source, hence warmer “inside” the jacket and “inside” the house. Which has what to do with the topic at hand?
While you’re trying to come up with an answer for that:
The earth absorbs 240 w/m2. At equilibrium, the earth emitts 240 w/m2. Temperature (accoding to you and your wrongly applied SB Law) is 255K
CO2 quintuples. The system is perturbed until equilibrium is once again established in which event:
The earth absorbs 240 w/m2. At equilibrium, the earth emitts 240 w/m2. Temperature (according to you and your wrongly applied SB Law) is 255K.
Change from quintupling CO2 = 0.

413. ferd berple says:

Bill Hunter says:
January 20, 2012 at 8:35 pm
“Yes, but only accounts for a small portion of the temperature gradient in the upper ocean.”
Any can disagree. Tell us why you disagree. What accounts for the other portion?

414. Been thinking about an increase over the SB average. It would be higher because of the thermal lag in a purely mechanical atmosphere system without GHG’s. In a GHG free atmosphere the molecules cannot shed the energy gained mechanically from the ground during the day. I do think that GHG’s would raise the temperature further, in line with the equations in Loudon, but not according to Hansen’s empirical relation.

415. Bart says:

davidmhoffer says:
January 20, 2012 at 8:10 pm
“There’s been an increase in heat stored in the system, but in terms of the average w/m2 exiting the system as a whole, they are exactly the same as they were before down to the last watt.
The water retained is the analogy to energy retained. And, if heat capacity is unchanged, that means the temperature must go up in the GHG paradigm.
However, here’s what I believe is wrong about the GHG paradigm: the example is inverted. The dam is already there. Having the dam a particular height means the water behind it is at a particular height. In introducing IR emitting gases, you are, in fact, opening up new floodgates in the dam (more avenues for energy to radiate away), and the water will go down.
DeWitt Payne says:
January 20, 2012 at 8:23 pm
Of course there’s an upper limit,…
I was speaking of a temperature limit. Your objection was that there was a 2nd law violation because the temperature could increase forever. It couldn’t for two reasons: 1) all real atmospheres will radiate somewhere 2) in the worst case, the atmosphere simply escapes and stops heating.
“Out of curiosity I calculated the pressure a function of altitude for a purely adiabatic atmosphere.”
You can’t get adiabatic conditions when there is no heat sink in the upper atmosphere. This is a basic assumption in all the text books when they calculate adiabatic lapse rates, and one of the items which led me to my hypothesis, which is that IR gases in the Earth’s atmosphere are, in fact, heat sinks.
DeWitt Payne says:
January 20, 2012 at 8:46 pm
“…”
I’d appreciate it if you try that again. You’re not talking about anything I’m talking about. I am saying that, on this hypothetical planet, the surface is a blackbody, but its emissions are suppressed while massive amounts of heat are being drawn out of it to feed an ever hungrier atmosphere. At least, that’s my current running hypothesis. It could change to accomodate new facts as I gather them. But, so far, I do not see any evidence that says this scenario is unphysical or impossible, and it is very appealing from the point of view of stability.

416. Crispin in Waterloo says:

ferd berple says:
January 20, 2012 at 7:19 pm
Willis says:
“IF GRAVITY ACTUALLY SEPARATES TEMPERATURE, WE HAVE FREE ENERGY FOREVER!”
If Willis says it, then he is pulling your leg. Gravity can affect a tall column of gas and will separate temperature, but there is no work being done in that process and there is no pump involved, just compression and expansion. As much material goes up as down. Just because there is a temperature gradient does not mean you can extract energy from it indefinitely because extraction will cool the whole system.
This is straightforward. A system at any given temperature above 0 K can be cooled. A system with a temperature gradient can be cooled using a heat engine that exploits the temperature gradient. But that is nothing like ‘free enery forever’ That is ‘stored energy being converted to a non-thermal form’.
A spherical planet with some gravity and an atmosphere isolated from the universe will have a temperature gradient from top to bottom, cold to hot, because of the universal gas law and Brownian motion. Energy can indeed be extracted from the temperature difference between the top and bottom of the system provided that device is not entirely made of gas – it has to not respond to the universal gas law. It will produce, say, electricity. That is a conversion of heat into electrical energy. The whole system cools in response. That is not free energy and ‘gravity’ will not make up for what is missing. That is a thermoelectric generator. Over time the bottom of atmosphere will cool until, in theory, the atmosphere condenses. Gravity does not ‘heat the atmosphere’ is causes the heat in the atmosphere to be unequally distributed according to the pressure gradient.

417. Bart says:

Bart says:
January 20, 2012 at 11:00 pm
davidmhoffer says:
January 20, 2012 at 8:10 pm
“There’s been an increase in heat stored in the system, but in terms of the average w/m2 exiting the system as a whole, they are exactly the same as they were before down to the last watt.”
I just realized your and Kevin’s thought experiment supports my hypothesis. As you say, all those photons backradiated into the Earth should just be spit back out again. So, why should there be gaps in the emissions at TOA in those bands?
Are they re-radiated back from the surface at even lower wavenumber? (There’s no way the Earth is re-radiating the backradiation at higher energy.) If so, shouldn’t we see a hump at lower wavenumbers in the emissions spectra? In fact, we see just the opposite: the emissions spectrum at TOA over Guam, for example (see here in Fig. 2), in the low wavenumber range appears to fit an isocline near 275K, while that at higher wavenumbers appears to follow a 300K or so isocline.
Curiouser and curiouser…
Now, consider my mechanism in which the IR absorbing gases actually pin down the spectrum in their radiative range, while the rest of the spectrum is trying to push itself up around it. That is a much better fit with what is actually measured!
DeWitt Payne says:
January 20, 2012 at 9:15 pm
“Because the surface temperature is so much higher, the 15 μm band of CO2 doesn’t contribute much. Even at 92 bar, there are still ranges of relatively low absorption for CO2 alone. However, those gaps are nearly filled by SO2 and H2O, even though the partial pressure of H2O is small. Replacing half the CO2 with nitrogen does cool the surface, but not by much.”
In light of my comment above, I note that the composite emissions spectrum of Venus is “pinned down” in the H2SO4 band, while tiny bits are taken out in the CO2 and other bands. How about giving it a go? Suppose, for the sake of argument, that I am right. Where does it lead you in interpreting Venus’ emissions spectrum?

418. In response to

The only way to transfer heat to space is via radiation, and the only way for the atmosphere to loose heat to space is to have greenhouse gases that radiate energy

Jordan says:
January 20, 2012 at 2:28 pm

All gases radiate. Search for “emissions spectrum”. wikki will give you a good introduction.

Hans Jelbring says:
January 20, 2012 at 5:21 pm

Wrong. Don´t you think that salt particles, droplets (clouds), and dust particles emits IR from the atmosphere. You might also have heard about lightning.

Come on guys, you are both missing the point. The basic question is – Does increasing the amount of greenhouse gases in the atmosphere cause the atmosphere to get warmer (the consensus) or colder? In my paper, I suggest a atmosphere made from a hypothetical gas that does not absorb or emit IR radiation. This avoids the very valid exceptions that both of you have made. In this very hypothetical case, the atmosphere has no way to loose energy to space and, therefore, becomes isothermal.
At that point, it does not matter if you add salt particles, O2, or CO2, there is now a mechanism for heat to escape the atmosphere. (However, with O2 the loss is so small it might not be measurable.) Since some of that heat returns to the surface, it gets warmer as the atmosphere cools.
As long as the atmosphere is optically thin, the entire thickness of the atmosphere will cool about the same amount and an adiabatic lapse rate will form near the surface. If the atmosphere becomes optically thick (nearly opaque), then only the top will cool significantly and the lapse rate will not be very close to the adiabatic rate.
On the real Earth, the dry adiabatic lapse rate is about 9.8 K/km, the typical measured troposphere lapse rate is about 6.5 K/km. With an atmosphere lacking any IR emitters, the lapse rate will be 0 K/km (isothermal). Since the actual lapse rate is between 0 and 9.8, if follows that the atmosphere is optically thick in the frequencies that matter.
Beside the mechanisms you have suggested, there are other cooling scenarios caused by pressure gradients produced by the surface temperature variations between the day and night sides of the planet, as well as the pole vs equator differences. But remember, the point of this exercise is not to describe some hypothetical planet, but to determine the function of greenhouse gases.

419. Willis Eschenbach says:

DeWitt Payne says:
January 20, 2012 at 9:59 am

Hans Jellbring,
Any surface radiation power exceeding 100 W/m^2 is bull regardless if it is from equatorial, midlatitude or polar regions during days or night. Just show how this fantasy power radiation changes between day and night in polar regions as an exsample.

Here’s a plot of upwelling IR radiation measured over 24 hours at Desert Rock, NV by a SURFRAD station there. It looks to be more than 100W/m² to me. Note that the time axis is UTC. Desert Rock is -8 hours from UTC so local noon would be 2000 on the time axis.
There are seven SURFRAD stations in the US. You can access the data here.

People, please pay attention to this interchange. Hans Jelbring asserted categorically that “Any surface radiation power exceeding 100 W/m^2 is bull.”
In response, DeWitt posted up an actual measurement from a surfrad station. It shows a 24 hour plot. The MEASURED, OBSERVED surface radiation swings between 300 (night) and 400 (day) watts per square metre. So what is “bull” is Hans’s crazy claim.
I want you all to consider the level of willful blindness about climate science that it would take to get to the year 2012 and still be making Hans’s claim that nowhere on the earth is there surface radiation exceeding 100 W/m2. I mean, to do that you would have to avert your eyes from half the scientific papers published about the climate. You’d have to never, ever google “upwelling longwave” to see if your 100 W/m2 claim is correct. You’d have to think that the Stefan-Boltzmann equation didn’t work. You’d have to never look at a global energy budget.
Tallbloke, upstream you claimed that I was making an “ad hominem” attack when I said:

If you are fighting basic ignorance of science, you will be deluged with ignorant people.
Not much I can do but just keep putting the facts out there.
Certainly there are a host of much more sophisticated threads, and those tend to attract a more scientifically literate commenter. But when you are discussing “gravito-thermal” theories …

Now … perhaps given Hans Jelbring’s demonstrated ignorance regarding upwelling radiation in this interchange, you might be willing to rethink your comment?
w.
PS—Please be clear why what I said is not an ad hominem attack. I am not saying that Hans’s scientific theories are wrong because Hans is ignorant of basic information about radiation. That would indeed be an ad hom attack, where you try to bring down the man’s scientific claims by attacking the man.
I am saying that Hans’s scientific theory are wrong, and that Hans is ignorant of basic information about radiation. The two are not linked. Hans’s theory fails on its own merits, with no reference to the author of the theory.
The same is true about my comment about how people who are generally ignorant of basic science believe in theories like Jelbrings. That’s not an ad-hom argument either. Saying that someone is ignorant of basic science does not mean that any given belief of theirs is wrong, that would also be an ad hominem attack.
You see, an ad hominem attack means that you are attacking the man rather than attacking the argument. I’m not saying that those folks arguments are all wrong, or are wrong because they don’t know science.
I’m just saying that a lot of them don’t understand basic science, which is a simple statement and not an ad hominem in any form.

420. Willis Eschenbach says:

Marc77 says:
January 20, 2012 at 12:00 pm

I have to disagree here. It is possible to make energy between the ground and the top of the atmosphere because the ground is warmer than space from the point of view of the atmosphere. The atmosphere does not see the Sun because it does not absorb in the UVs. So space is very cold for it. If there was a blob of nitrogen in orbit around the Earth, it would be cold. So it would be possible to make energy between this blob of gas and the ground. Don’t forget, the ground is warmer than space in the IR.

Once again, we are not discussing whether we can draw power from the Earth’s atmosphere. Everyone agrees we can do that. We are discussing whether we can draw power from either the atmosphere in Jelbring’s thought experiment, or (equivalently) from a tall, thermally insulated cylinder.
w.

421. Willis Eschenbach says:

Joe Born says:
January 20, 2012 at 12:35 pm

… I have to confess that two weeks ago I was arguing over at tallbloke’s place for the same position you’re taking now: http://tallbloke.wordpress.com/2012/01/01/hans-jelbring-the-greenhouse-effect-as-a-function-of-atmospheric-mass/#comment-12926. Currently I think I was wrong then and that you’re wrong now. Maybe by tomorrow you and Dr. Brown will have convinced me otherwise.

Joe, all considerations about the mechanism go nowhere. Consider the outcome. If it’s true that gravity can separate molecules by temperature, then we can pull energy out of tall insulated cylinders of air, Jelbring is right and we never have to worry about energy again.
Do you believe that we can do that? Really?
w.

422. Willis Eschenbach says:

Bart says:
January 20, 2012 at 3:35 pm

Willis Eschenbach says:
January 19, 2012 at 11:48 pm

<So in the Jelbring thought experiment you are saying the atmosphere never, ever achieves thermal equilibrium? If not … why can’t we pull work out of it with a thermocouple?"

You can. Remember, there is an outside energy source which is constantly adding energy to the system. Is the Earth at equilibrium? How do windmills work?

Thanks, Bart. You seem to have momentarily forgotten that in the Jelbring thought experiment, the planet and atmosphere are surrounded by an impermeable perfectly insulating sphere which doesn’t allow any energy in or out. It is a sealed-off portion of the universe, with a planet and an atmosphere.
It is in that world, which I have nicknamed “Stygia” for the stygian blackness inside the shell, than Hans says the atmosphere will be thermally stratified by gravity.
Since (as you say above) the inhabitants of Stygia could pull work out of such a temperature difference, then they could use it to light up their eternal darkness.
As you know, that would be a perpetual motion machine, so Jelbring’s hypothesis is falsified.
w.

423. Robany says:

Please can anyone point out any logical flaws in the following reasoning:
Consider two systems, one gravitating and one not. Each is surrounded by a perfectly insulating, perfectly reflective shell and contains a spherical, homogeneous, black-body planet with a homogeneous, transparent atmosphere.
In both cases the surface of the planet radiates energy which is reflected completely back onto the planet’s surface by the shell, yielding no net radiative transfer from the planet. There exists a boundary condition at the surface of the planet such that the planet’s temperature and the atmospheric temperature are the same.
In the non-gravitating case, any temperature differences in the atmosphere will be eliminated by conduction. Thus the atmosphere is a uniform temperature that matches the surface temperature of the planet and has uniform pressure and density at all altitudes.
Now add gravity to this system. By doing so we have added a considerable amount of total energy to the system in the form of gravitational potential energy. The mass distribution of the atmosphere changes to ensure that at each altitude the pressure is equal to the pressure exerted by the atmosphere above it. The compression of the atmosphere at lower altitudes causes it to heat up, as per the ideal gas law. We now have pressure, density and temperature gradients decreasing with altitude as we are all familiar with from Earth.
Now we must return to our boundary condition: the planet’s surface must be the same temperature as the atmospheric temperature at the boundary. The temperature of the atmosphere at the surface has risen as it was heated by compression. There is now a temperature difference between the planet’s surface and the surface layer of the atmosphere. Thus energy will flow from the hotter body to the cooler, from the atmosphere to the planet until our boundary condition is restored.
The gravitating planet’s surface is now hotter than the non-gravitating planet. The GPE released by redistributing the mass of the atmosphere was converted to thermal energy. Now we turn to our other boundary condition: the insulating, reflecting shell that makes this a closed system. No energy can leave the system and a gravitating system has greater total energy than a non-gravitating one. Since the atmosphere is transparent the increased radiation of the hotter black-body planet is perfectly reflected back by the shell to the planet. The gravitating system has higher total energy and higher planet temperature. The increase in total energy is proportional to the GPE of the atmosphere which is proportional the the mass of the atmosphere. More massive atmosphere yields higher temperatures.
A non-gravitating system is isothermal, a gravitating one is not.
So, unless someone wants to point out the flaw in the logic, we now have a stable system containing a temperature gradient that should persist indefinitely.
Now let’s turn to the perpetual motion issue with the heat engine. I think we all agree that the heat engine will operate (do work) as there is a temperature gradient. However in doing work to produce light, the heat engine must reduce the temperature gradient that makes it operate since this is a closed system. If thermal energy is converted to light, there’s less thermal energy to go round. Stygia is now lit but colder. The surface temperature boundary condition ensures that the planet cools.
Let’s suppose that the heat engine is a real one and not 100% efficient, it gives off heat. This will heat the atmosphere locally and the atmosphere will radiate the heat. Since the atmosphere is transparent and the reflective shell is perfect, the only place for this radiated heat to be absorbed is by the planet (which is now cooler thanks to the heat engine).
Stygia is lit but colder. With the perfectly reflecting shell the light will bounce around the system indefinitely until it is absorbed. The only absorber is the planet. As the planet absorbs the light, the light’s energy is converted back to heat and the planet warms. As the planet warms, so does the surface layer of the atmosphere and the thermal gradient in the atmosphere is increased once more.
We’ve ended up with a system where energy is converted by the heat engine to light and local heating of the atmosphere depleting the temperature gradient available to the heat engine. The heat engine would theoretically convert all energy in the system to light making the system uniformly cold and the heat engine stop working. However the local heating of the atmosphere and the energy in the light is reabsorbed by the planet as there is nowhere else in the closed system for it to go. This heats the planet and restores the temperature gradient which means the heat engine keeps running.
The entropy in the system can only increase OR STAY THE SAME. The theoretically perfect, lossless system described can operate because the specification of perfect losslessness means the entropy change for all the steps is zero. Thermodynamic laws are NOT violated.
I think where the column of air arguments are failing is that they do not account for the redistribution of energy in a perfect, closed system. Taking energy from the column of air must either deplete the energy in the air column or it must be replenished by taking energy from the rest of the system. Taking the energy from the rest of the system depletes the thermal gradient that is being used to generate the energy thus energy generation will eventually stop. Still no free, limitless energy for everyone.

424. Willis Eschenbach says:

Downdraft says:
January 20, 2012 at 3:37 pm

I am still puzzling over the idea that a column of air will reach an isothermal state or not. I took Dr. Brown’s explanation as a starting point and made changes to it that reflect my view. I hope he doesn’t mind. Who would think that such a simple thought experiment would be so complex.
Imagine a plane surface in the gas. …

Forget about the mechanism, Downdraft, and start with what makes sense.
Suppose Jelbring were right and that a tall insulated cylinder of air would thermally stratify by gravity, with warm air at the bottom and cold air at the top. If so, we could use that temperature difference to do work.
Of course, the operation of our heat engine would cool the warm bottom air inside the tall insulated cylinder, and warm the cool air at the top. That’s what heat engines do. But Jelbring says no worries, gravity will separate the warm air and cold air again so the heat engine can continue running indefinitely.
Now Downdraft, be honest with me here … do you really think we can pull work forever out of a tall, perfectly insulated cylinder of air?
I didn’t think so. Which means that the air in the cylinder must be isothermal, and that Jelbring’s hypothesis cannot be right.
If you start thinking about mechanisms from there, from what you know to make sense, you’ll have more chance of sussing it out.
All the best.
w.

425. Scot Allen says:

I don’t think Dr Brown appreciates the tiny, but significant, exchanges of kinetic for gravitational potential energy between his layers. Additionally, he treats these layers as being much more dense than they are. Even at the surface, 99.9% of a volume of air is vacuum. A conduction model doesn’t work well here, I think.
Let’s assume the atmosphere is made from mostly empty layers (it is mostly vacuum, afterall) that are 10^-5cm think. This is about the average distance a molecule in air travels before colliding with another molecule. Also assume a molecule traveling about 500 m/s. This is also the mean speed of an air molecule at the surface.
It has kinetic energy (ignoring rotational energy) of an N2 molecule then is
1/2 * 28 * 1.66 x 10^-27 kg * (500 m/s)^2 == 5.81×10^-21 J.
A molecule passing through the mostly empty space from the bottom of a layer to the top of the layer has kinetic energy converted to gravitational potential energy so that
28 * 1.66 x 10^-27 kg * (9.8 m/(s^2)) * 10^-5 cm = 4.56×10^-32 J of kinetic energy is lost (or gained if moving down from a higher layer).
This seems small but it is significant.
Imagine one molecule at the bottom of the atmosphere made energetic by contact with the surface of the Earth hitting another molecule 10^-5cm above it and so on through the layers as the atmosphere tries to reach equilibrium. Each time a lower molecule loses some kinetic energy to gravitational potential energy as it travels across the current layer before it strikes a molecule in the next layer above it. At 10km, 4.56×10^-21 J has been converted to gravitational potential energy — a significant amount when compared with the 5.81×10^-21 J at the start. The reverse is true, too. Molecules propelled upward are matched by molecules falling downward and each downward falling molecule gains 4.56×10^-32 J of kinetic energy as it falls through a 10^-5cm layer.
These differences in kinetic energy in each layer must translate into different temperatures in each layer.
Of course linear kinetic energy in the direction normal the surface of the Earth isn’t the only energy in a N2 molecule. There is kinetic energy parallel to the surface. There is also rotational energy, too. A thermometer will integrate all these to determine a temperature. This is one reason why the temperature of the atmosphere at 10km is higher than what is predicted. Still, much energy is in the form of vertical kinetic energy and this is converted from kinetic to gravitational as molecules move upwardly. The absence of this kinetic energy must be reflected in a lower measured temperature.

426. Looks like the very basics of “science” are still not settled 😉
Lets forget the gravity for a moment. Claim of many of us is, that the bulk atmosphere itself (N2+O2) is from a considerable, if not full part, responsible for warmer average than Moon (and much less diurnal variations, which is at least so important).
Earth day is much cooler than on the Moon. We have clouds, water surface evaporation, cloud/snow albedo and air thermals cooling our day. Without bulk atmosphere, none of it should work. The main “greenhouse gas” – water vapor – in its various forms causes net daytime cooling.
Earth night is much warmer than on the Moon, on average by tremendous 240° C. Temperature in 2m altitude, measured by thermometer, is equal to number of molecular collisions per given area per given time unit, and their speed of movement. Without bulk atmosphere, there are no molecular collisions to be measured. Mere presence of “greenhouse gases” is not sufficient. Mars black body temperature and actual temperature is the same – 310K – even there is 6,000 ppm of CO2 in its atmosphere. However, this is already 95% of the whole atmosphere, it means it is very thin. There is nothing, which should hold the warmth from the surface, heated by sunlight (or long-wave IR coming from that CO2, if we believe so). How thick would be the back radiation arrow in Kiehl-Trenberth diagram for Mars? How many Watts would be assigned to it? Net result is still ZERO. Still 310K.
The ultimate point of all that is to say, that the claim “greenhouse gases raise surface temperature by 33K” is totally wrong; 33K is wrong and the whole attribution to “GHG” only is wrong as well.

427. Willis Eschenbach says:

Jordan says:
January 20, 2012 at 3:48 pm

“IF GRAVITY ACTUALLY SEPARATES TEMPERATURE, WE HAVE FREE ENERGY FOREVER!”

This assumes a heat engine can transfer energy from its source as efficiently as transfer of energy into its source. I do not believe this assumption has been justified where conditions at the source are not the same as conditions at the sink. .

Thanks, Jordan. You and several others have said that practical problems in utilizing the heat to do work invalidate the proof. They do not. The existence of the temperature difference means we can extract work, whether or not we’ve invented a way to do so yet.
In fact, there is a lovely plan upthread to use two columns of different gases. As they have a different specific heat Cp, at every level but one they will be at different temperatures. This gets past the question of the distance between the ends of the thermocouples.
Also, your “rate of transfer” argument above doesn’t work. All I have to do is turn off the heat engine for a little while. Then gravity (says Jelbring) would re-sort the molecules by temperature. Tomorrow, I turn on my heat engine again. Perpetual motion.
w.

428. Willis Eschenbach says:

KevinK says:
January 20, 2012 at 4:04 pm

Willis wrote;

“If you are fighting basic ignorance of science, you will be deluged with ignorant people. Not much I can do but just keep putting the facts out there.”

With all due respect, I am most certainly NOT ignorant of science.

Dang, bro’, with all due respect, I didn’t say you were.
w.

429. Willis Eschenbach says:

Bart says:
January 20, 2012 at 4:23 pm

Downdraft says:
January 20, 2012 at 3:37 pm

“I am still puzzling over the idea that a column of air will reach an isothermal state or not.”

It will, but if and only if equilibrium is established. So, it becomes a circular argument.

I don’t understand. Are you claiming that the temperature in a tall insulated cylinder of air will never reach equilibrium?
w.

430. Scot Allen says:

Willis Eschenbach says:
January 20, 2012 at 11:48 pm

Suppose Jelbring were right and that a tall insulated cylinder of air would thermally stratify by gravity, with warm air at the bottom and cold air at the top. If so, we could use that temperature difference to do work.

Are you certain? Suppose the engine were a Stirling engine. A Stirling engine could do no work as the gas inside the engine would stratify just as the gas in the insulated cylinder.

431. scf says:

Having read Willis’ comments, and Jellbring’s comments about Willis’ comments, I am quite surprised. How on earth is it possible that Jellbring has such a weak grasp of physics? Yes, his paper was peer-reviewed, which is what is just so very surprising! And as Willis points out, this is not an ad hominem attack, I have read his comments and come to the conclusion he has some very basic concepts wrong. He says:
I have already pointed out that a “perpetuum mobile” is possible to construct in our real atmosphere since the cold air at the top of Mount Everest for sure is colder than air at the surface.
Yet he does not understand what is obviously wrong with that statement. That’s not a perpetual motion machine, that’s just another energy source like any other that we have today. The energy is derived from outside sources (the sun), which in turn causes the temperature gradient, which in turn allows you to extract work.
Willis is correct, if gravity were to provide a temperature gradient, then you could create a perpetual motion machine, you could do work from that gradient, which in theory would reduce the temperature gradient, but of course the theory states that gravity would restore the gradient once more (that’s the Jellbring theory!), thus enabling the perpetual extraction of work! This is energy creation from nothing other than a force (gravity), hence impossible.
And of course we have other commenters like fred berple pointing out that temperature gradients exist in the real world. How utterly irrelevant.
Meanwhile, tallbloke keeps making comments that exhibit a very weak understanding of basic physics, not even using the terminology correctly for basic concepts such as energy, work, and temperature.
I just don’t understand how people who clearly have a weak grasp of physics to be so utterly and totally oblivious to the fact that they have a weak grasp of physics.

432. Joe Born says:

Dewitt Payne: “The entropy of an isothermal atmosphere is higher than for an atmosphere with an adiabatic lapse rate.”
You believe that. Willis believes that. Robert Brown believes that. I believe that. But our believing it doesn’t make it true. Nor does Willis’s heat-engine “proof,” because it begs the question. I.e., by assuming that the heat engine will work, he’s assuming that the adiabatic-lapse-rate atmosphere’s entropy is lower than an isothermal one, which, ultimately, is what he set out to prove.
The only proof would be to show that the number of states that fall within the “isothermal” definition vastly exceeds the number that fall within the adiabatic-lapse-rate definition. And, of course, your response would be that you have indeed seen such proofs.
But have you really? Here I’ll help you The Coombes and Laue paper discussed at Tallbloke’s Talkshop’ Loshmidt thread, http://tallbloke.wordpress.com/2012/01/04/the-loschmidt-gravito-thermal-effect-old-controversy-new-relevance/ , does indeed purport to provide a proof that the maximum-entropy state is isothermal even in the presence of gravity.
However, the Velasco et al. paper also discussed at that site demonstrates that Coombes & Laue’s conclusion is only an approximation asymptotically approached as the number of molecules gets large; for any finite number of molecules, the maximum-entropy state has a non-zero lapse rate given implicitly (for a monatomic ideal gas) by the (altitude-dependent) expression I set forth above.
Does the mean that Helbring is right? No. The lapse rate at which Velasco et al. arrive is much less than the adiabatic lapse rate. Indeed, by most people’s standards, it is negligible for any number of molecules of which we’d take notice.
But what it does mean is that neither Willis’s nor Robert Brown’s nor your “proof” is valid; none of them does anything more than state a conclusion. (The same is true of that Science of Doom discussion the summer before last.) And, technically, that conclusion is wrong.
Or, at least it’s wrong if Velasco et al. are right. Now, I’m no physicist, and I found Velasco et al. (and the Román et al. paper on which it depends) tough sledding. But the relationship they derive, namely (3E/(5N-2))(1-mgz/E) for the mean single-molecule kinetic energy, where N is the number of molecules, E is total system energy, m is molecular mass, g is the acceleration of gravity, and z is altitude, is clearly correct for N = 1, unlike the isothermal conclusion everyone thinks he remembers.

433. Crispin in Waterloo says:

Willis, you said:
“It is in that world, which I have nicknamed “Stygia” for the stygian blackness inside the shell, than Hans says the atmosphere will be thermally stratified by gravity.”
This is correct.
“Since (as you say above) the inhabitants of Stygia could pull work out of such a temperature difference, then they could use it to light up their eternal darkness.”
Briefly. Extracting heat energy from the atmosphere would result in net cooling.
>As you know, that would be a perpetual motion machine, so Jelbring’s hypothesis is falsified.
Incorrect. It is falsified but not for the reason you state (that it will not re-stratify). If Jelbring says that the atmosphere will re-sort the temperature into a stratified one, he is correct. If he does not mention that the system will have cooled (net) he is missing something. If he thinks gravity will add heat to the atmosphere he is incorrect. The moment he says that, he has created a perpetual motion machine.
Re-stratification does not mean ‘re-heating’. There is no energy input. The energy extraction from the heat engine will work. The atmosphere will indeed re-stratify. It is not re-heated while doing so; no net gain in energy from gravity, there being no mechanism for it. Ergo your clear statement that re-stratification = perpetual motion is incorrect.
Suppose you employed a 100% efficient heat engine in a stratified atmosphere. Wherever it was placed, it would cool the system. Overall, the system would cool and eventually have no heat left. The fact that a less efficient heat engine would take longer, and involve re-stratification, does not change the physics: work can be done using the temperature difference. The system will wind down. How is that a perpetual motion machine? It is the extraction of energy from a heat battery. Nothing more.
If Jelbring says it will continue to generate energy indefinitely, that is a contradiction of the Law of Conservation. If you say that the atmosphere will not re-stratify, that is a contradiction of the Universal Gas Law. You are correct to say his claim creates a perpetual motion machine IF he states that the upper gas will gain energy from gravity as it drops lower. It will warm, but not to the previous temperature.
A ‘gas packet’ will increase in temperature when it goes down, but temperature is not a measure of energy. Energy is thermal mass times temperature. If you cram more mass into a unit volume, the temperature rises because there is more mass in there not because each unit making up that mass, on its own, gained energy. “Temperature” is a measure of how many bangings there are into the thermocouple. You can’t measure energy with a thermocouple.
It is akin to heating a spring v.s. compressing a spring. Both are reservoirs of energy. You cannot tell how much energy is in the spring by measuring the temperature only. Stacking springs vertically in a gravitational field will compress the bottom one the most and it will have more energy that the top ones, even if they are all the same temperature. You can extract work by decompressing the bottom springs to the same length as the top ones, but it reduces the total stored energy. Imperfect analogy but the point needs to be made – extracting energy will wind down the system. Gravity will not make it up.

434. Willis Eschenbach says:

jae says:
January 20, 2012 at 6:53 pm

Willis:

“jae, I fear I don’t have a clue which “empirical evidence” you are speaking of. If it has to do with the N&Z hypothesis, I don’t understand the hypothesis so “evidence” means nothing. Let me know which evidence and which theory you’re talking about.

More light and less heat would help here.”
Well, I will assume you are being honest, because you always have been, AFAIK. But…maybe because you get a “headache” when you read Huffman’s stuff (your words, I think), you did not really read his stuff and pay attention to the DATA (aka, EMPIRICAL EVIDENCE!). Same with the other papers. It seems that the atmospheres of other planetoids that have atmospheres have temperatures that are not correlated in any way to the amounts or types of GHGs present in those atmospheres. You continue to ignore all that part of the question, and do not confront it/explain your position. Is it confirmation bias? Old age? Ego? What, Willis?

First, I fear that what happens on other planets is of little interest to me. The planets are so different from the Earth, and we understand our own climate so poorly even though we live in it, that what is happening on Jupiter or Venus can provide little insight, falsification, or support for theories about the Earth.
Second, I’m still not clear (other than planetoids) what evidence you say exists in the “papers”.
Third, I don’t know what “papers” other than Huffman you are discussing. There is no evidence in Jelbring’s paper that I know of.
Fourth, Joel pointed out above that the planetary “evidence” in N&Z is a fit of an equation with many free parameters, viz:

All they have done is fit some data using a form with many free parameters: There are 4 free parameters in Equation (7) and that is not even including any freedom they may have exercised in choosing the fitting form, choosing how to define T_gb, or even which estimates of the average surface pressure and temperature of various bodies to use.

I am not impressed by a fit with four visible free parameters plus selection parameters. That has no evidentiary value at all.
As to whether I “ignore” the question of the planets, no, I don’t. I’m just not impressed by arguments about what’s happening on Venus. Down at the bottom of the Venusian atmosphere, CO2 is neither a gas nor a liquid, but a supercritical liquid. If you think that has some relevance to the Earth’s climate, I don’t see it.
Finally, you ask why I “do not confront it/explain your position. Is it confirmation bias? Old age? Ego? What, Willis?”
I am under no obligation to either confront something, or explain why I have not done so, merely because you think it is important. Look at this thread. How many people have posted how many different theories and claims and explanations and evidence and insights and all the rest?
Some of it I reply to. Some I don’t. Some I follow up on. Some I don’t. Time is short, the road is long.
A fit of an equation with 4 free parameters to a bunch of carefully selected planetary data is not something I follow up on.
And if I do or don’t follow up on it, I do not owe you an explanation. In this case I didn’t discuss it, because, frankly, it is meaningless.
I am not amused by your accusations of confirmation bias and the rest. I advise you to leave them off the next post. Bear in mind that it may not be answered, for the reasons listed above. I have answered you this time in part so you will know why I may not answer you in the future.
w.

I have finally found time to re-run my empirical experiment into the N&Z hypothesis. This time I followed “Joules Verne’s” suggestion and regulated the pressure in the test chambers. I used an air bladder (hot water bottle) and weights (bricks) to maintain constant pressure in the high pressure chamber.
Due to thunderstorms and rain I was unable to use sunlight as a long wave source and had to use a flood lamp (too much IR). However the results were just as before. The chamber with the higher pressure always rises to a higher temperature when illuminated. I should point out that illumination is only started when the chambers have been pressurised and allowed to equalise temperatures.
With just 6 house bricks on the air bladder, chamber temperature differentials of over 4 degrees were observable. Again I reiterate that low and high pressure chambers were allowed to equalise in temperature before illumination.
When the weather clears I will re run the tests with sunlight instead of a floodlamp. In the meantime I am confident in claiming that Nicolov and Zeller are correct and that Willis and Joel are entirely wrong. Again.

436. Scot Allen says:

scf says:
January 21, 2012 at 1:37 am

Willis is correct, if gravity were to provide a temperature gradient, then you could create a perpetual motion machine, you could do work from that gradient,

How can you be certain work could be done from that gradient? Gravity may prevent that.
The working substance in a heat engine, after doing work, must move to the cold sink. The cold sink in this hypothetical perpetual motion machine is high above the heat source. Energy must be used to raise it. I suspect the energy required to do that is equal to the energy that appears can be extracted from the gradient.

437. Willis Eschenbach says:

jae says:
January 20, 2012 at 8:22 pm

“jae says:
January 19, 2012 at 7:05 pm
DAMMIT, WILLIS:
PLEASE ADDRESS THE EMPIRICAL EVIDENCE, WHICH WILL ULTIMATELY RESOLVE THIS ARGUMENT! WHY DO YOU REFUSE TO DO THIS?
[Moderator’s suggestion: If you didn’t YELL at him maybe more would be accomplished? Maybe? -REP]”

It seems that some of Anthony’s “moderators” need some moderation. Is it really the moderator’s place to tell me just how to express myself on a blog? I think NOT! Just what the hell do you think you are?

It was a suggestion offered in friendship, in support of you getting some traction, jae. No reason to be upset.
w.

438. Joe Born says:

Willis Eschenbach: “If it’s true that gravity can separate molecules by temperature, then we can pull energy out of tall insulated cylinders of air.”
Without realizing it, you’ve begged the question. “We can pull energy out of tall insulated cylinders of air” in which a non-zero lapse rate prevails, but only if that air is not at maximum entropy–and you have not shown that maximum entropy necessarily requires a zero lapse rate.
You think you know it’s true. And, as I mentioned above to DeWitt Payne, people like Robert Brown think they’ve proved it. But the only real way to prove it is to show that the number of states that exhibit isothermality greatly exceeds the number thereof that exhibit a non-zero lapse rate. And, to this non-physicist at least, the Velasco et al. paper, together with the Román et al. paper on which it relies, shows that it does not.
Now, as I mentioned above to DeWitt Payne, that doesn’t mean that Jelbring is right; in fact, it shows he’s wrong. But it also shows you haven’t proved he’s wrong.

439. Bill Illis says:

Willis Eschenbach says:
January 20, 2012 at 11:41 pm
DeWitt Payne says:
January 20, 2012 at 9:59 am
Hans Jellbring,
“Any surface radiation power exceeding 100 W/m^2 is bull regardless if it is from equatorial, midlatitude or polar regions during days or night. Just show how this fantasy power radiation changes between day and night in polar regions as an exsample.”
Here’s a plot of upwelling IR radiation measured over 24 hours at Desert Rock, NV by a SURFRAD station there. It looks to be more than 100W/m² to me. Note that the time axis is UTC. Desert Rock is -8 hours from UTC so local noon would be 2000 on the time axis.
There are seven SURFRAD stations in the US. You can access the data here.
People, please pay attention to this interchange. Hans Jelbring asserted categorically that “Any surface radiation power exceeding 100 W/m^2 is bull.”
In response, DeWitt posted up an actual measurement from a surfrad station. It shows a 24 hour plot. The MEASURED, OBSERVED surface radiation swings between 300 (night) and 400 (day) watts per square metre
———————-
Here are all the radiation flows (In and out) for Table Mountain Co. SURFRAD station for the 24 hour period of Nov, 29, 2009. (I did this more than a year ago so that is why the date) .
http://img140.imageshack.us/img140/4109/tablemountainall.png
http://img12.imageshack.us/img12/3225/tablemountainnets.png

440. John Marshall says:

How you can dismiss the atmospheres of the other planets I find incredible. They all obey the same laws of physics. It is just that you GHGers are wedded to the claims that somehow a trace gas drives temperature.
You also fail to accept that compressing a gas will increase its kinetic energy which results in a higher temperature. That is what adiabatic means.
How about this for an add on to the compression theory. Convecting gas in the atmosphere will cool as it rises at the Saturated Adiabatic Lapse Rate, around 5C/Km rise, and form clouds at height. This rising air causes air at height to descend but this air is dry, having formed clouds, and warms at the Dry adiabatic Lapse Rate, 9.8C/KM, so will arrive back at the surface warmer than when it convected. (Like a vertically looped Chinook Wind). This warms the surface above the theoretical BB temperature not the GHG theory that violates the laws of thermodynamics.
I wonder if you can be bothered to get down this far in the reply list?

441. Bart says:

Willis Eschenbach says:
January 21, 2012 at 12:33 am

“You seem to have momentarily forgotten that in the Jelbring thought experiment, the planet and atmosphere are surrounded by an impermeable perfectly insulating sphere which doesn’t allow any energy in or out.”
Well, you can’t forget what you never knew. To be truthful, I haven’t looked at the Jelbring hypothesis much – it sounded fishy to me from the get-go. The setup you describe, and which I have now looked at the paper to see for myself, is IMHO very contrived. If you take away the insulation, and there’s no influx, then the atmosphere will freeze and even the usual caveats about the ideal gas law go out the window.
I have been looking at the standard greenhouse theory and trying to find loopholes in its physical basis. What I have found is that it depends very much on an assertion that a derived formula (SB) intended for matter in thermodynamic equilibrium holds even in situations which are far from that condition. This is a loophole.
In researching the topic, I have found relatively narrow experimental results existing for non-equilibrium radiative behavior, and there is evidently quite a bit of current research going on into the very question of how it works. To borrow a phrase, the science is not settled. It appears plausible to me that rapid conductance of heat could significantly reduce thermal radiation, as the heat gets conducted away before the particles can radiate away their energy.
I have also found that the standard explanation that IR emitters heat the surface has a mirror image explanation with the same resulting steady state behavior, but with very different non-equilibrium dynamics. Looking at things from this perspective gives an actual reason for why an equilibrium condition in an emitting atmosphere is even approached, and solves a couple of other dilemmas which I have pointed out now:
1) How did the Earth ever heat up enough to unfreeze the water vapor that presumably contributes most of the “greenhouse” warming to heat the planet to its present state?
2) Why is there a gap in IR emitter bands at TOA when the IR radiation broadcasted back to the Earth should simply re-radiate back out?
To those, I will add a third I only just started thinking about. We all know by now that CO2 and CH4 levels increase after emergence from an ice age, and not before. Why? Well, if IR emitters actually make things colder, then recovery should proceed after enough of them have been sequestered by a change of state, and the warming which releases them again should set into motion a new decline. And, that is what we see.
Willis Eschenbach says:
January 21, 2012 at 1:21 am

“Are you claiming that the temperature in a tall insulated cylinder of air will never reach equilibrium?”
The SB loophole allows this to be a physically realizable possibility.

442. scf says:

jae says: “you did not really read his stuff and pay attention to the DATA (aka, EMPIRICAL EVIDENCE!). Same with the other papers. It seems that the atmospheres of other planetoids that have atmospheres have temperatures that are not correlated in any way to the amounts or types of GHGs present in those atmospheres. ”
I don’t understand how this is supposed to be evidence. You have a small sample set. You have a million other variables with each of those planets, You might as well be claiming that the colours of those planets are the cause of the unknown temperature differentials, rather than the size.

443. Bart says:

And, in another forehead slapping moment, I suddenly realized I do not even have to argue that SB violation is possible. That argument is tailored for a fictitious planet with a non-radiating atmosphere, which can never actually exist. All that is needed is to establish that there is a tendency for heat to accumulate in an atmosphere (which there trivially is).
As the heat rises, the emitters in the atmosphere will draw more and more of it off, increasing the allowable temperature rise of the surface to remain in radiative equilibrium according to SB. The rising temperature stops when the emitters have taken enough out such that the surface temperature induced radiation balances with the incoming flux from the Sun and the backradiation from the emitters.
Under this dynamic if, for example, you had no IR emitters, but emitters only say in the visible part of the spectrum, the temperature would climb until those emitters can establish an equilibrium. The total emissions still balance on the way up because the energy radiated by those emitters is orders of magnitude more energetic than IR emitters.
So, in this way, a planet’s equilibrium temperature is set by the minimum threshold at which available emitters can balance all the fluxes.
And, adding more IR emitters to the Earth’s atmosphere will tend to cool, rather than heat, it.

444. Bart says:

So, your temperature rises to the SB limit. The tails of the first major emitter back-radiate, which allows your temperature to rise more within the SB limit. So, you get more back-radiation, and your allowable temperature rises some more. And, so on, until you have reached the point where your surface is radiating significantly into the main lobe of the emitter, and you reach an equilibrium.
That’s it!

445. Fred Allen says:

Thanks for pointing out my errors A Physicist.

446. Hans Jelbring says:

scf says:
January 21, 2012 at 1:37 am
“Having read Willis’ comments, and Jelbring’s comments about Willis’ comments, I am quite surprised. How on earth is it possible that Jelbring has such a weak grasp of physics?”
Please, point out exactly what part is weak in my paper insteaed of using general degrading statments about my understanding in physics. Willis behavior in this respect has been outstanding and what I consider him to be is not printable. The results in the article stands and falls by applying 1:st law of thermodynamics and 2:nd law of thermodynamics. Are these 2 laws familiar to you? Just tell me which one is wrong or point to any other fault IN THE ARTICLE. Zeroth´s law is not applicable in this case since gravity is involved and it makes the constant energy per any equal mass within the insulated sphere constant. This is equivalent to the adiabatic temperatuer lapse rate of -g/Cp. To avoid the sill PM argumet I confirm that a system that has reached maximum entropy cannot include a PM so I agree with you on that point. The treated atmosphere only contain ideal gases and no perpetuum mobile.
Willis and you seem to share the same problem. You don´t understand my paper and still you know that it is wrong by adding unspecified circumstances. Just read it and comment line by line what is wrong. Don´t forget to comment on observational evidence that support the model results which primarily are observed temperture lapse rates on other planets that support the model result. That includes observed temperature lapse rates on Venus, Mars, Titan, Jupiter, Neptun and Uranus.

447. Willis Eschenbach;
I am not impressed by a fit with four visible free parameters plus selection parameters. That has no evidentiary value at all.>>>
I, on the other hand, am not impressed with an accusation that isn’t true. Go back and take a look at the equations yourself Willis and count the g_d d_mned parameters. Equation 7 is actually two equations on a single line, and further, it is an interim step. Each of the two equations expressed in Equation 7 has 2 variables. You cannot possibly be suggesting that we count up the variables in two different equations and accuse N&Z of having four variables in a single equation, can you? Oh wait. You just did.
The purpose of the TWO equations shown in Equation 7 (which should be expressed as Step 7 for clarity) are to explain the transformation that leads to Equation 8, which is their FINAL equation, and which contains TWO variables, from which the surface T of 8 planets is then calculated.
So, your harsh criticism of N&Z being nothing more than curve fitting based on four free parameters is falsified simply by reading what they said instead of reading what someone else SAYS they said. Are we skeptics seeking the truth? Or rabid confirmation biased critics stooping to half truths and omitted facts to support our position?

448. Willis Eschenbach;
People, please pay attention to this interchange. Hans Jelbring asserted categorically that “Any surface radiation power exceeding 100 W/m^2 is bull.”>>>>
People, please pay attention to Hans Jelbring’s entire comment where it becomes clear that English is not his first language and that he struggles in several places to articulate clearly what he means. Rather than going all attack dog on his choice of words, how about cutting the guy some slack and asking for clarification?
Hans Jelbring,
Any surface radiation power exceeding 100 W/m^2 is bull regardless if it is from equatorial, midlatitude or polar regions during days or night. Just show how this fantasy power radiation changes between day and night in polar regions as an exsample.>>>
Hans, could you expand on this statement for clarity? Your wording suggests that the surface of the earth never exceeds radiance of 100 w/m2 which just isn’t correct. Is this what you meant? Or were you referring to net radiation? Or some sort of averaged number over time? We don’t understand exactly what the 100 w/m2 you are speaking of here actually refers to.

449. A physicist says:

jae says: PLEASE ADDRESS THE EMPIRICAL EVIDENCE, WHICH WILL ULTIMATELY RESOLVE THIS ARGUMENT! WHY DO YOU REFUSE TO DO THIS?

OK, jae, let’s provide some empirical evidence (and in the process, hopefully we’ll depoliticize this argument).
We’ll consider a different system, that has NO politics associated to it, and yet has (essentially) similar physics. That system is a cryogenic tank, also called a “dewar”, also called a “thermos flask.”
In its simplest form, a cryogenic tank is insulated by a layer of vacuum (say 1 cm thick). Of course, heat can be carried across that gap by radiation. NASA engineers (among others) would like to reduce that radiative heat flow, so that spaceships can hold liquid oxygen/hydrogen/helium longer.
Weird-sounding engineering idea: Fill that one centimeter vacuum gap with ten (or more) ultrathin, aluminized, lightly crumpled, sheets of plastic film (typically ordinary mylar), with each mylar sheet having a thickness of only 0.001 cm (or less), such that the thickness of each sheet is tiny compared to the thickness of the vacuum gap, and in particular, such that the net thermal resistance of all the mylar layer’s together is negligible.
Now a photon traversing the vacuum gap is absorbed (by an ultrathin mylar sheet) and reemitted … absorbed (by a sheet) and reemitted … absorbed (by a sheet) and reemitted … (analogously, as infrared is absorbed (by CO2) and reemitted … absorbed (by CO2) and reemitted … absorbed (by CO2) and reemitted … ).
Question: What happens to the heat leak from the vacuum gap? Does the gap insulate the tank better, or worse? (analogously, does CO2 make our atmosphere insulate better, or worse?)
Answer: As discovered by NASA in the 1960s, the thin-layered vaccum tanks — called “multilayer superinsulation tanks” insulate heat flow orders of magnitude better than tanks without superinsulation. That is why every cryogenic tank manufacturer in the world now uses superinsulation.
So that is one more “Elevator Answer” to Willis’ question. Adding CO2 to the Earth atmosphere has effects similar to adding superinsulation to a cryogenic tank. In both cases, thermal conductivity is reduced, with the (desired) result that NASA’s spaceship tanks retain their cryogen longer, and with the (similar, but sobering) result that the Earth’s surface warms to a higher temperature from the sun’s solar input.
Ultrashort Elevator Answer: CO2 acts as a multilayer superinsulator.
The point being, there’s essentially zero doubt (among scientists and engineers) regarding multilayer superinsulation; both theory and empirical observation agree that multilayer superinsulation just plain works.
And this is yet another reason why there’s essentially zero doubt (among scientists and engineers) regarding the GHE in general: the GHE just plain works

450. Bryan says:

I said early on in this thread
“The isothermal/adiabatic distribution for an isolated ideal gas in a gravitational field has long been debated.
For the isothermal distribution we have Maxwell, Boltzmann and Clausius.
For the adiabatic distribution we have Loschmidt, Laplace and Lagrange.
The smart money must be with the isothermal advocates but I would not regard this as a debate of which was settled and of historical interest only.
Here for instance is a member of the physics department of the University of California making a very up to date case for the adiabatic distribution.
http://arxiv.org/PS_cache/arxiv/pdf/0812/0812.4990v3.pdf
Its a pity that Willis who last week was with the adiabatic camp, now thinks to hold such a position is only held by “ignorant” people.
This is an overreaction which has more place on a Deltoid thread than here.
However anyone who makes the adiabatic distribution for an thermally isolated ideal gas in a gravitational field a cornerstone of their theory about the real adiabatic atmosphere is needlessly going against the orthodox physics.
A bit like Claes Johnson and photons.
Its much better to stay within the orthodox framework of physics when addressing a general problem such as the Earths Climate.
Then separately argue the case for the existence or otherwise of photons or whether an adiabatic distribution for isolated ideal gas in a gravitational field is appropriate.

451. Bart;
Bart says:
January 21, 2012 at 3:21 am
And, in another forehead slapping moment, I suddenly realized I do not even have to argue that SB violation is possible.>>>
You NAILED it!
Well, until the last sentence…
Bart;
And, adding more IR emitters to the Earth’s atmosphere will tend to cool, rather than heat, it.>>>>
Nope. You should get to the same surface temperature, or close to it.
By opening up more pathways for emission to space, you don’t actually cool anything provided that you consider the whole surface and the average of T^4 of that surface. I think it easier to explain by going the other way. Take a system with a given number of pathways and shut some of them off. Does the temperature rise? One would think so, but not by nearly as much as one would think.
As soon as you shut some of the pathways off, that forces energy that otherwise would have escaped to be recirculated by other means. But the over all temperature does NOT need to rise (or more accurately, it doesn’t need to rise as much as one would think) to re-establish equilibrium. Because the energy is not being forced to re-circulate, it must also have the effect of re-distributing energy about the planet. Shut off some pathways, and there is no other possible result but that net energy flow from the tropics to the poles increases. The result is, because P varies with T^4, is that the coldest parts of the planet experience the most increase in T, which in turn results in a planet of more uniform temperature.
Equilibrium still requires that emission to space match absorption. By shutting off some channels, we force the emission to be spread around more than it would otherwise. Equilibrium however still arrives at the exact same w/m2 being emitted because absorption didn’t change. We get a cooler tropics and a warmer high latitudes, but the average of T^4 remains identical. If we fall into the trap of averaging T instead of T^4, we will get an average of T that is higher than it was before we shut some of those channels off.
Your main thought process howevere is correct. Shut down some channels, or create some new ones, and you redistribute flux in terms of what frequencies and how much escape from where. But the surface temperature simply “evens out” until equilibrium is established again. But change in net energy balance? There isn’t any.

452. Joe Born says:

A Physicist: “With regard to thermodynamics and transport theory (which is broadly what this WUWT topic is about), an historically recent and very broadly applicable framework regards thermodynamics and transport theory as (essentially) the study of the geometry of flow on manifolds, specifically the study of Hamiltonian dynamical flows on manifolds that are equipped with a symplectic structure.”
That’s beyond what vestigial mathematical skill remains from the last math course I took, over forty years ago. But, since you appear to be conversant in these matters, perhaps you could point out where I am wrong in understanding the above-identified Velasco et al. paper to reason from Hamiltonian dynamics to a conclusion that at equilibrium an ideal gas in a gravitational field will exhibit a non-zero temperature lapse rate. Or maybe you could point out the equation at which that paper or the Román et al. paper on which it depends went off track. Those papers are discussed in this thread: http://tallbloke.wordpress.com/2012/01/04/the-loschmidt-gravito-thermal-effect-old-controversy-new-relevance/.
In this context it is not enough to say that Velasco et al.’s lapse rate approaches zero as the number of molecules approaches infinity, because Willis’s argument is based on the lapse rate’s being zero at equilibrium even for a finite number of molecules.

453. BenAW says:

Both the GHE and the N&Z paper try to solve a problem in explaining the current avg. temp
of 288K, the first starts from 255K, the other from 154,7K.
What both approaches are neglecting is that the earths surface consist mostly of oceans,
70% area, minimum 3 km deep and a temperature on average of +2C, already 20K higher
than the blackbody temperature the GHE uses when the sun has heated the blackbody.
Ocean surface temperature is on average 290K, just 15K higher than the temperature of the
deep oceans. This warmer layer is ~200m deep in the tropics, reducing to 0m near the
polar circles.
So instead of heating a blackbody from 0K to 255K (255K difference) all the sun has to do
is heat a smal part of the oceans from 275K to 290K, just 15K difference.
This warm ocean then heats the atmosphere, and results in our pleasant 288K average
temperature near the surface.
As background information may serve that the earth radius is ~6370 km, ocean depth
~3km, oceanbed 5 -10 km. The other 6350+ km are hot to very hot, (400K – >5000K)
although it is assumed that allmost no heat is flowing from the hot interior to the oceans
Ocean temps are basically steady since system earth is in radiative balance with the sun.
Ben Wouters

454. This thought experiment is similar to elevator music. It is there, but not particularly memorable.
I saw one commenter taking a correct approach. He(she) looked at the gas properties, including Prantl number and did an amazing thing, calculated the changing properties with temperature, viscosity, thermal capacity and pressure. I mentioned that isothermal conditions in the tall column of air would require changes in the mixed gas viscosity, perfect insulation and the velocity/energy of the upper most molecules would be greater than the lower. If you take the top and bottom off the tube, what would happen? So it is an unrealistic thought experiment, but maybe a start to a useful one. If that theoretical column was integrated over the entire surface, using the calculations to determine the final temperature, viscosity and pressure of each column, then we would be on to something, but not an elevator description or back of the envelop kinda thing.
There have been a lot of comments mentioning conductivity. About time. Now how about the change in conductivity? CO2 changes the conductivity of a mixed gas. H2O doesn’t have as much impact on the conductivity of a mixed gas. It takes the change in conductive hundreds of years to thousands of years to change climate, in the mean time, Ein to the oceans is never equal to Eout of the oceans. Shouldn’t that be where the problem starts? A ball of water in space over eons absorbing more energy that it emits? Then one fine day it reaches near equilibrium. Gravity does have an impact there. Then add layers of atmosphere one at a time.
The top down approach so far has been problematic, why not start from the bottom up?

455. DavidB says:

I will frankly admit that I haven’t read all the comments, but I see that some people still insist that gravity would still raise the temperature at the bottom of the atmosphere as compared with the top, by means of compression.
If this is the case, the argument wouldn’t be confined to a gaseous amosphere. It would also apply to any solid column – say, a granite pillar – since all solid bodies are at least slightly elastic. To find an easily visualisible model, consider a tall hollow tube filled with tennis balls. The balls have weight, and the balls at the bottom of the tube have more weight above them than those near the top, so they are more compressed. The density of balls, and the pressure they exert on each other through their elasticity, is greater at the bottom.
We assume that the tube is perfectly insulated from the outside world (with respect to heat flow).
Now, does anyone suggest that in equilibrium the balls at the bottom will be hotter than those at the top? If so, what is to prevent heat being conducted from the hotter balls to the cooler ones until the temperature is equalised?
Note that I refer to the situation in equilibrium. If we disturb that equilibrium, say by putting in more balls at the top of the tube, there will be a temporary increase in temperature at the bottom, as the balls there are further compressed, but again the heat generated by compression (which is actually a form of kinetic energy) will eventually be diffused evenly throughout the tube. Does anyone disagree?
If they agree in the case of an elastic solid column, but disagree in the case of a gas, they need to explain the difference. Of course in the case of a gas there will be convection as well as conduction. If the gas were a perfect Newtonian fluid, I suppose that by adding more gas at the top of the column we might set up a perpetual circulation, doing no net work, just as if we drop a perfectly elastic tennis ball we can set up a perpetual bouncing motion. But there are no perfect fluids, any more than there are perectly elastic tennis balls. In any real gas, without any new input of energy, the convection current would eventually come to a halt as its energy is dissipated by friction and converted to heat.

456. Richard M says:

davidmhoffer says:
January 20, 2012 at 8:10 pm

David, you’re pretty close to what I have been saying ever since Ira’s response to the K&Z hypothesis . It’s what I have been calling the maximum GHE. If you look at my comments over the last two weeks you will your description is very close. However, I don’t think your dam analogy is right. More water behind the dam would indicate a warmer climate.
It’s more like an overflow valve. The dam is full and any more energy just gets kicked out the overflow. It’s more like a V-shaped river. The initial flow of water increases the height behind the dam quickly. However, as the lake grows the same amount of water increases the height less and less. The overflow amount can match this rise and the water level does not increase.
In the atmosphere I think this is due to the fact that CO2 has both a warming and cooling effect. The GHE gets maximized once these two effects become equal. This occurs because the warming effect is a stronger one but diminishes more quickly due to saturation.
PS. I even pointed out that the warming from adding 100 ppm of CO2 would be .005% … which is the increase in mass when you convert O2 to CO2.

457. Joel Shore says:

davidmhoffer says:

There’s been an increase in heat stored in the system, but in terms of the average w/m2 exiting the system as a whole, they are exactly the same as they were before down to the last watt. Since everyone wants to average w/m2 and convert that to degrees, I say let ‘em. If they cannot show that the incoming watts absorbed has changed, then at equilibrium the outgoing watts have to be the same too. Since the outgoing watts are the same, temperature of the planet is the same. Go ahead folks, use SB Law to contradict that.

The earth absorbs 240 w/m2. At equilibrium, the earth emitts 240 w/m2. Temperature (accoding to you and your wrongly applied SB Law) is 255K
CO2 quintuples. The system is perturbed until equilibrium is once again established in which event:
The earth absorbs 240 w/m2. At equilibrium, the earth emitts 240 w/m2. Temperature (according to you and your wrongly applied SB Law) is 255K.
Change from quintupling CO2 = 0.

The above is the exact argument made by Alan Siddons, one of the “Slaying the Skydragon” crew. It is an extremely silly argument. Yes, the amount the Earth is emitting as seen from space has to be the same amount it is receiving from the sun in radiative balance…It has to be. However, the amount emitted by the surface of the Earth is not. The radiative greenhouse effect is the only thing that can explain how the surface of the Earth can be at an average temperature so high that it emits ~390 W/m^2 while the Earth as seen from space only emits ~240 W/m^2 and is thus still in radiative balance with what it receives from the sun.
Congratulations on now embracing the arguments of the “there is no greenhouse effect” crew who you once laughed at!

I dam a river and form a lake. At equilibrium, the river flowing in has a flow rate of 240 m3/min. Outflow at the dam = 240 m3/min. I raise the dam one meter. After a short period of time, the flow rate in is… 240 m3/min and the outflow is 240 m3/min. The depth of the water increases by 1 meter, and the potential energy stored as a consequence of that can be calculated, but the flow rate at equilibrium changes not one bit. The same is true of doubling C02. Temporary fluctuation in the system, but one equilibrium is established again, the incoming w/m2 and the outgoing w/m2 are exactly what they were before. There’s been an increase in heat stored in the system, but in terms of the average w/m2 exiting the system as a whole, they are exactly the same as they were before down to the last watt. Since everyone wants to average w/m2 and convert that to degrees, I say let ‘em. If they cannot show that the incoming watts absorbed has changed, then at equilibrium the outgoing watts have to be the same too. Since the outgoing watts are the same, temperature of the planet is the same. Go ahead folks, use SB Law to contradict that.

No…The water depth is the analog of the surface temperature. And, while the W/m^2 at the top-of-the-atmosphere is the same as it was, the W/m^2 leaving the surface is not.

The greater the mass of the atmosphere, the lower the chance of any energy packet escaping to space.

The only way that the atmosphere can lower the probability of radiative energy from the surface from escaping to space is radiatively…i.e., by absorbing this energy. So, the only way that the mass of the atmosphere can come into it is in a way that changes the radiative absorption (which it can do to some extent by broadening of the absorption lines of the GHGs).

458. Joel Shore says:

Response to http://wattsupwiththat.com/2012/01/19/perpetuum-mobile/#comment-871539 wherein David M Hoffer invents a new way to count parameters:
Great…Now all I have to do if I perform a fit of y vs. x with 100 free parameters is break it into two equations, one that defines some intermediate quantity as a function of x in terms of 99 of the parameters and the other that gives the final relation between this intermediate quantity and what I want (y) with 1 free parameter. Then I will have magically gone from a 100 parameter fit to a 1 parameter fit and everyone will be very impressed with my fit. I’ll have to remember that trick!

459. Richard M says:

davidmhoffer says:
January 21, 2012 at 4:07 am
[Willis Eschenbach;
I am not impressed by a fit with four visible free parameters plus selection parameters. That has no evidentiary value at all.>>>]
I, on the other hand, am not impressed with an accusation that isn’t true. Go back and take a look at the equations yourself Willis and count the g_d d_mned parameters. Equation 7 is actually two equations on a single line, and further, it is an interim step. Each of the two equations expressed in Equation 7 has 2 variables. You cannot possibly be suggesting that we count up the variables in two different equations and accuse N&Z of having four variables in a single equation, can you? Oh wait. You just did.
The purpose of the TWO equations shown in Equation 7 (which should be expressed as Step 7 for clarity) are to explain the transformation that leads to Equation 8, which is their FINAL equation, and which contains TWO variables, from which the surface T of 8 planets is then calculated.

This was the same argument Joel tried to use against me back in Ira’s thread. It’s unfortunate that they are willing to discard what may very well be a valid correlation by simply waving their hands.
The two variable are atmospheric pressure and input energy. Those two define the GHE on every one of the planets. I think the non-GHG atmosphere is simply a red herring. GHGs are required, they just have a maximum effect in a gravity field.
This makes a lot of sense when you think about the effective radiation height. The incoming solar energy is what drives the atmosphere to be well mixed … to a point. Lower energy or higher pressure, less mixing. Higher energy or lower pressure, more mixing. The mixing drives the GHGs to a point in the atmosphere that ends up defining the effective radiation height. Once you’ve got enough GHGs to block almost all outgoing radiation you have maxed out the GHE.

460. A. C. Osborn says:

The Title of this thread and the whole arguement by mr Eschenbach is a Strawman.
His hypothetical machine is quite impossible and he knows it. You cannot have a perfectly insulated column of air, just as he admits you cannot get any “work” out of downwelling IR.
He also admits that ice can form in the desert at night even though the temperatures are above freezing.
There have been many experiments that show that Cooling occurs, not warming from the night sky and not just in deserts. See Roy Spencer’s Experiment, where he thinks the Air in the Box should fall even lower than 5C lower than the surrounding air temperature and it is DIR that is keeping it from falling that much lower.
Talk about fool yourself with pre-conceived ideas.

461. Joel Shore says:

Richard M says:

The two variable are atmospheric pressure and input energy. Those two define the GHE on every one of the planets. I think the non-GHG atmosphere is simply a red herring. GHGs are required, they just have a maximum effect in a gravity field.

Yes, there are 2 variables but there are at least 4 free parameters in their fit.
And, they are not fitting to the GHG effect. They are fitting to their “surface temperature enhancement”. Only 3 of the 8 bodies that they consider have a very significant radiative greenhouse effect and only for one of those bodies (Venus) is the greenhouse effect that majority of what they define as the “surface enhancement effect”. (For the Earth, the radiative greenhouse effect is ~25% of their total surface temperature enhancement.) Most of the “surface temperature enhancement” is simply due to an evening out of the temperature distribution with no change in the W/m^2 emitted by the surface.
It is strange that people who have not understood the most basic facts about what they have done nonetheless seem to think that they have extremely wise and intelligent opinions about it!

462. Bart says:
January 20, 2012 at 6:38 pm
KevinK says:
January 20, 2012 at 4:04 pm
“When the energy returns to the surface from the “GHG” you cannot ADD it to the energy arriving from the Sun to produce an alleged “energy budget”.”
Energy is constantly coming in. If some of it is made to hang around longer than instantaneously, before the new batch arrives, then you will accumulate a net offset.
It’s not about increasing energy flow, which is always nearly constant. It’s about impeding that flow so that you keep more close to you.

Hi Bart. Do we not have a similar situation with the effect of gravity creating a gradient of pressure in an atmospheric mass? Because air is compressible, it means the density of the air will be greater near the surface, and energy hangs around longer in denser masses of a given composition than it does in less dense masses of that same composition due to the higher heat capacity.

463. A physicist says:

A Physicist says: “With regard to thermodynamics and transport theory (which is broadly what this WUWT topic is about), an historically recent and very broadly applicable framework regards thermodynamics and transport theory as (essentially) the study of the geometry of flow on manifolds, specifically the study of Hamiltonian dynamical flows on manifolds that are equipped with a symplectic structure.”

Joe Born says: Since you appear to be conversant in these matters, perhaps you could point out where I am wrong in understanding the above-identified Velasco et al. paper to reason from Hamiltonian dynamics to a conclusion that at equilibrium an ideal gas in a gravitational field will exhibit a non-zero temperature lapse rate. Or maybe you could point out the equation at which that paper or the Román et al. paper on which it depends went off track. Those papers are discussed inTallBloke’s thread The Loschmidt Gravito-Thermal Effect: Old controversy – new relevance.

Thank you, Joe, for this very reasonable question, which I will try to answer concretely.
From the viewpoint of geometric thermodynamics, every conserved quantity is associated to a thermodynamic potential. All systems conserve energy, and the thermodynamic potential associated to energy is called temperature. Some systems (but not all) conserve particle number, and the (less familiar) thermodynamic potential that is associated to particle number is called the chemical potential. Ideal gases are an example of a system that does conserve both energy and particle number.
If we regard the atmosphere as a stack of thin layers, we observe that each layer exchanges both energy and particles with the layers above and below it, and moreover the exchange of particles is associated to work done against a gravitational potential.
So a preliminary accounting of any thermodynamical theory of the atmosphere must ask:
(1) Does this theory account for the temperature potential?
(2) Does this theory account for the chemical potential?
(3) Does this theory account for work done against the gravitational potential?
Unless all three potentials — temperature, chemical, and gravitational — are accounted, the theory is thermodynamically wrong.
With reference to Tallbloke’s page, we find a mistaken implication in the second paragraph:

“Loschmidt’s rationale is straightforward […] no net particle flow from top to bottom is required; thus this is heat conduction, not convection.”

Mistakenly, the Loschmidt analysis goes on to completely neglect the chemical potential, on the grounds (presumably) that because there is no net exchange of particles, the thermodynamic effects associated to the exchange of individual particles can be neglected.
But since the exchange of individual particles really does occur (and is in fact the mechanism that sustains a pressure-and density gradient), Loschmidt’s analysis is wrong to neglect the chemical potential.
One way to get clear on these matters is to extend the analysis to thermodynamically account (explicitly) not only temperature and chemical potential gradients, but also pressure and density gradients. The result is simply that (at equilibrium) atmospheric pressure and density vary so as to ensure that both the temperature and the chemical potential are uniform.
Ultrashort Elevator Summary: Gravito-thermal theories wrongly neglect chemical potentials.

464. DavidB says:
January 21, 2012 at 5:34 am
I see that some people still insist that gravity would still raise the temperature at the bottom of the atmosphere as compared with the top, by means of compression.
consider a tall hollow tube filled with tennis balls. The balls have weight, and the balls at the bottom of the tube have more weight above them than those near the top, so they are more compressed. The density of balls, and the pressure they exert on each other through their elasticity, is greater at the bottom.
We assume that the tube is perfectly insulated from the outside world (with respect to heat flow).
Now, does anyone suggest that in equilibrium the balls at the bottom will be hotter than those at the top? If so, what is to prevent heat being conducted from the hotter balls to the cooler ones until the temperature is equalised?

This goes back to the proof I offered Duke.edu physicist Robert Brown up near the top of the thread. he said:
“if A and B are placed in thermal contact, they will be in mutual thermal equilibrium, specifically no net heat will flow from A to B or B to A.” That’s the zeroth law.”
And I pointed out:
Assuming your A and B have at least some dimension, then a thermal gradient across them would mean that the top surface of A will be at the same temperature as the bottom surface of B where they contact. Therefore no heat will flow. Even so, the average temperature of the whole of body A will be higher than that of B. QED.

465. But add in some adiabatic action – a nice little bit of vigorous vertical mixing – and the temperature gradient reappears. The elevator speech goes thus: “When air moves in a vertical airflow from the top to the bottom it is compressed and thus heats. When air moves in a vertical airflow from the bottom to the top it is decompressed and thus cools. In an atmosphere with a lot of vertical mixing you therefore will see a temperature gradient.”
Close. One has to ask what drives the “vigorous vertical mixing”. The answer is, temperature difference in the non-equilibrium, open system caused by differential heating. What does the heating? The Sun, of course. It isn’t so much air compressing and heating as it falls as it is air being heated at the bottom and rising (and displacing cooler denser air as it does so). The convective flow actually cools the bottom when it is being heated, without exception, although it does establish the lapse rate. Otherwise you have another of those processes that moves heat from colder to hotter.
The other point is that your elevator speech has nothing to do with either Jelbring or N&Z. The general thermodynamics of adiabatic expansion and its importance in the atmosphere is long known and completely absent from both of their papers. They both assert that something about the atmosphere differentially warms it due to gravity, not that the sun heats the ground, establishes convective flow that moves the heat around (cooling the ground in the process) and that radiative imbalance in GHGs cause differential cooling of the upper troposphere to maintain the energy flow.
Without the rapid cooling of the upper atmosphere that keeps it cold relative to the ground — cooling that is strictly radiation, because sooner or later the Earth has to lose the incoming heat from the sun — the adiabatic warming profile would not exist, and in parts of the atmosphere that profile inverts even as it is (for example, over the arctic in the long arctic night) as further proof that this isn’t an atmospheric compression effect, it is plain old convection.
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466. Joel Shore says:

Richard M says:

This was the same argument Joel tried to use against me back in Ira’s thread. It’s unfortunate that they are willing to discard what may very well be a valid correlation by simply waving their hands.

It wasn’t hand-waving at all! I am the ONLY ONE to my knowledge who has even bothered to replicate their fitting procedure. Then I showed how I could change the temperature of the three bodies that have a significant greenhouse effect to essentially eliminate that effect and still get almost as good a fit using their fitting form (even though the data for N_TE was now quite a bit squirrelier since Venus now had a value considerably smaller than Earth and Titan and I made no attempt to change the fitting form or definition of T_sb to optimize the fit)!
I have also explained that there is likely a generally positive correlation between P and their N_TE because as you add an atmosphere to a planet, you will even out the temperature distribution, raising the average temperature. (Higher pressure also tends to correlate with more greenhouse gases and it can also cause broadening of the GHG absorption lines, although I think this is a smaller issue in the positive correlation that they see because, for the most part, their surface temperature enhancement does not really reflect the radiative greenhouse effect.)

467. Here’s a shorter elevator speech:
If there is a temperature gradient between two parts of a system, net heat flows from the warmer part to the cooler part. If there is net heat flow within the system, it is not in equilibrium.

Wow, so perfectly correct! Two laws of thermodynamics (0 and 2). Done.
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468. DavidB says:

Tallbloke:
Your last argument in response to my ‘tennis ball’ model seems to prove too much. Using this argument you could prove that heat can never be conducted along a metal rod. Suppose one end of the rod is in a fire, and the other end in a bowl of ice water. There is a continuous gradient of temperature along the rod. But if we conceptualise the rod as a collection of infinitely thin ‘slices’, each slice will be at the same temperature as the next one. Therefore, by your argument, ‘no heat will flow’. And yet it does!

469. Michael Larkin says:

Willis,
I’m just a bozo on the bus, so I post with trepidation. I was wondering about something that seems to have been addressed by Crispin above. Starting with a perfectly insulated column of non-GHG gasses initially at uniform temperature and pressure throughout, suppose you cause it to appear on the surface of a planet, and suppose that its gravity does indeed cause a temperature gradient to appear.
Then, suppose you take advantage of the temperature differential at the top and bottom to drive a heat engine, which reduces the temperature differential. And so on. That seems to me to say that at some point, the engine will stop.
My question is this: is Jelbring saying that gravity will somehow add heat to the system, thereby restoring initial heat differential? Is he actually explicitly saying that he is creating a perpetual motion machine, or is that something you have inferred? Could he simply be saying that gravity will cause a temperature differential?
I don’t know enough physics (hardly any, in fact), to venture an opinion and certainly an elevator speech is far beyond my capabilities. But I’d just like to know what Jelbring is explicitly saying and whether you might be addressing a straw man argument. I’m not being in any way antagonistic – this is a genuine and open question asked out of ignorance.

470. The problem is that GHGs and back radiation does not explain the vertical temperature of the atmosphere. The inescapable conclusion of this is that the GHG model is not capable of explaining our atmosphere and that there is more at ‘play’ than the GHG model would suggest.
Why not? I would have said that this is precisely what they predict, although the observed vertical temperature profile of the atmosphere is due to convection induced by differential heating as a part of the overall greenhouse process. In order to get the greenhouse effect, you need to radiate (in a frequency band) from the greenhouse gases up where the atmosphere is cold instead of down where it is as warm as the surface. That’s all it takes. That is experimentally observed to be the case in the actual IR spectrum as measured by NASA satellites.
The real question is: Why do you think one needs additional explanations at all?

471. Willis Eschenbach says:
January 20, 2012 at 11:56 pm
Joe Born says:
January 20, 2012 at 12:35 pm
… I have to confess that two weeks ago I was arguing over at tallbloke’s place for the same position you’re taking now: http://tallbloke.wordpress.com/2012/01/01/hans-jelbring-the-greenhouse-effect-as-a-function-of-atmospheric-mass/#comment-12926. Currently I think I was wrong then and that you’re wrong now. Maybe by tomorrow you and Dr. Brown will have convinced me otherwise.
Joe, all considerations about the mechanism go nowhere. Consider the outcome. If it’s true that gravity can separate molecules by temperature, then we can pull energy out of tall insulated cylinders of air, Jelbring is right and we never have to worry about energy again.
Do you believe that we can do that? Really?

Willis, the rules for falsifying a proposition by appeal to the consequent theoretical constructability of a perpetual motion machine of the second kind are very clear. You have to specify the machine and demonstrate that it will produce work.
Armwaving is insufficient.
I made this point a lot earlier in this thread and you ignored it. Just as I pointed out to Robert brown why his appeal to “the zero’th law failed and he ignored that too.
Unresponsiveness speaks volumes.

472. jjthoms says:

A Physicist:
Multi layer insulation – Never knew that!
http://www.technifab.com/cryogenic-resource-library/cryogenic-insulation.html
==
RADIATION FROM THE SKY
From the excellent source of info:
Pat Arnott – thank you!
Atmospheric longwave irradiance uncertainty: Pyrgeometers compared to an absolute sky-scanning radiometer, atmospheric emitted radiance interferometer, and radiative transfer model calculations Rolf Philipona, etal.
Please check out fig 3:
Figure 3. Longwave downward irradiance measured with all
pyrgeometers and the absolute sky-scanning radiometer from
September 22 to 29, 1999, at SGP. Field calibration and Albrecht
et al. formula with C, k2, and K is used for all pyrgeometers.
Nighttime and daytime slots are used for the analysis
of nighttime and daytime measurements.
If I read this correctly there is not much difference in LW IR between day and night.
Around 20 to 50%
Now note that this is LW IR so most of the solar sw input is not present. and solar IR is small
We know(?) that N2 and O2 and Argon do not emit much (zero mainly) IR..
But obviously the sw solar hits the ground gets re-emitted as cool LW ir. this gets reflected (re-emitted actually) back down by IR (or magic depending on your point of view). So this would explain the daytime level. Some of the GHGs will transfer warmth to the non ghgs by collision some will be radiated upwards.
At night there is NO source of solar input, and only a warm atmosphere. So where is the night time IR coming from? The system measures radiation not temperature, The non GHGs cannot emit radiation. So we are left with magic or GHGs.
Now combine this info with the down and up spectra shown in slide 9 of:
http://www.patarnott.com/atms749/powerpoint/ch6_GP.ppt
Where the GHG emissions are obvious.
they are reduced in TOA flux and increased in down welling flux.
Someone said but why is it miss from TOA if it goes down it must also go out. But of course some gets absorbed by the sea/land and provides heat which will be spread thinly over the BB radiation spectrum.
Can anyone explain these OBSERVED an recorde effects without GHGs?

473. The air moving up and down exchanges potential energy (PE) for kinetic energy (KE). The air moving down loses PE but gains KE, and vice versa for the air moving up. A higher KE means a higher temperature, a lower KE means a lower temperature. So the air moving down increases in temperature (KE), while the air moving up decreases in temperature (KE). This will maintain the adiabatic lapse rate, warmer air at the bottom of the column and cooler air at the top.
Your second point is wrong, there is no equalisation of temperature. Therefore, your conclusion in the third point of your elevator speech is also wrong.

Ah, so the air is moving, is it? What part of equilibrium is escaping you?
Now try again where the air is not moving in bulk because there is no differential heating or cooling of the air, which is trapped in an adiabatic container with no heat flow in or out. It quickly — for all practical purposes instantaneously — develops a pressure gradient and (in response to its bulk compressibility) density gradient, so that there is no bulk transport up or down the air column. At that point, heat moves from higher temperature to lower temperature within the gas because that is what heat does. In order for heat not to flow, the gas would have to not conduct, not thermally mix, not be a physical gas at all.
As you note, the temperature of the gas is directly proportional to its kinetic energy, but molecules of gas are not on average moving up and down the gas column so there is no net conversion of kinetic energy to potential or vice versa. They are however, colliding and exchanging kinetic energy. Those collisions, on average, share the kinetic energy equally among all of the molecules. Any time a molecule has more than the average, it is likely to (on average) lose it in collisions to others, any time one has less it is likely to gain it.
What maintains the adiabatic lapse rate is convection caused by differential heating of the gas column, specifically more heat being delivered to the bottom. Why is it so very difficult for you to see how having a spontaneous separation of temperature in a gas column due to gravity enables a perpetual motion machine of the second kind to be built, and thus is absolutely impossible?
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474. DavidB says:
January 21, 2012 at 7:34 am
Tallbloke:
Your last argument in response to my ‘tennis ball’ model seems to prove too much. Using this argument you could prove that heat can never be conducted along a metal rod. Suppose one end of the rod is in a fire, and the other end in a bowl of ice water. There is a continuous gradient of temperature along the rod. But if we conceptualise the rod as a collection of infinitely thin ‘slices’, each slice will be at the same temperature as the next one. Therefore, by your argument, ‘no heat will flow’. And yet it does!

Hi David. My argument was assuming an energy equilibrium with a consequent thermal gradient as in Jelbring’s hypothesis. Clearly, if you start stacking extra energy in at one end, heat will flow. This doesn’t affect my argument.
Cheers
Rog

475. If we wanted gravity derived concepts for heat, we should look at the temperature profiles of planets like Jupiter to see if there is a corresponding gravity induced effect. A quick look at the temperature profile here:
Not the best choice of examples. Jupiter is radiating more heat than it receives because it is still slowly collapsing at the center. What you want is a planet that is in (near) thermal equilibrium, with an atmosphere too thick for the center to be differentially heated by sunlight. The other problem is that the figure you post only goes to the base of the troposphere. The troposphere is by definition the part of the atmosphere that is differentially warmed at the bottom and cooled at the top and exhibits (approximately) an adiabatic lapse rate maintained by vertical convection.
The interesting question is — what is the thermal profile inside the troposphere? The atmospheres of the gas giants do not stop at the bottom of the troposphere. It is difficult to maintain convection (of any depth) while heating from the top. It is not at all unreasonable that the interior atmosphere of the gas giants resembles nothing more than the oceans of the Earth, with a more or less constant temperature and very little convection.
Nobody argues that the troposphere isn’t warmer at the bottom and cooler at the top. That’s what a troposphere is — the part of the atmosphere that is warmer at the bottom and cooler at the top. If you look at the very same figures for Jupiter (and for that matter Uranus or other planets) you can also see the layering and composition of the greenhouse gases in those atmospheres that seem to establish the thermal gradient that drives the convection that establishes the adiabatic lapse rate that perpetuates the greenhouse effect and makes the troposphere’s thermal distribution dynamically stable.
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476. Robert Brown says:
January 21, 2012 at 7:24 am
Here’s a shorter elevator speech:
If there is a temperature gradient between two parts of a system, net heat flows from the warmer part to the cooler part. If there is net heat flow within the system, it is not in equilibrium.
Wow, so perfectly correct! Two laws of thermodynamics (0 and 2). Done.

I’ll add it to my collection of potentially conflicting formulations of the thermodynamics laws – thanks for endorsing it.

477. A physicist says:

tallbloke says: Willis, the rules for falsifying a proposition by appeal to the constructability of a perpetual motion machine of the second kind are very clear. You have to specify the machine and demonstrate that it will produce work.
Armwaving is insufficient. I made this point a lot earlier in this thread and you ignored it.

Tallbloke, your statement is wrong-on-the-facts: Willis (and I) did describe a perpetual motion of the second kind, namely a thermopile column, said column having its warm end at ground-level and its cold end at altitude.
And the mistake in “gravito-thermal” theories is evident too: these theories include a thermodynamic potential (namely the temperature) together with a gravitational potential, and yet they (wrongly) neglecting the chemical potential.
Just to mention, ideal gases do have a chemical potential, whose effects must be included in any thermodynamically consistent theory that involves particle exchange (in this case, the exchange of molecules between layers of the atmosphere). Because “gravito-thermal” theories mistakenly omit the ideal gas chemical potential, it is unsurprising that the predictions of “gravito-thermal” theory violate basic thermodynamical principles (precisely as Willis asserted at the beginning of this post).
Hopefully, further study of the theory of chemical potentials will clarify these issues for the authors and fans of “gravito-thermal” theories. Wikipedia’s article on chemical potentials is a good start, and includes many further references.

478. Joel Shore;
Great…Now all I have to do if I perform a fit of y vs. x with 100 free parameters is break it into two equations>>>
Stop Joel. You are making a fool of yourself. Their final equation is Equation 8 and it has two variables in it. Two. count ’em. Two.
Joel Shore;
The above is the exact argument made by Alan Siddons, one of the “Slaying the Skydragon” crew. It is an extremely silly argument. >>>
Unable to refute it you instead try to equate it to something else. Is it right or isn’t it?
Joel Shore;
The radiative greenhouse effect is the only thing that can explain how the surface of the Earth can be at an average temperature so high that it emits ~390 W/m^2 while the Earth as seen from space only emits ~240 W/m^2 and is thus still in radiative balance with what it receives from the sun.>>>
Really Joel? Really? You cling to math so ridiculously wrong that your attempt to justify it is just pathetic. You have no idea what the theoretical black body temperature of the earth is, you have no idea what the practical black body temperature of the earth is, and thus you have no idea what the difference between the two is, let alone what causes it. But do read BenAW’s comment upthread where he has a nice explanation of EXACTLY how it works. You insist on not only ignoring the falacies introduced into your conclusions by the misaplication of SB Law, you insist also on ignoring the heat capacity of the planet, a point that I have made to you many times and which you continue to ignore.
You earned my respect in a variety of threads a while back, you have now lost it entirely and I think it tragic that someone as supposedly intelligent as Willis Eschenbach has somehow been duped by your duplicity.

479. Robert Brown says:
January 21, 2012 at 7:50 am
Why is it so very difficult for you to see how having a spontaneous separation of temperature in a gas column due to gravity enables a perpetual motion machine of the second kind to be built, and thus is absolutely impossible

As I said to Willis, armwaving is insufficient.
The rules for falsifying a proposition by appeal to the consequent theoretical constructability of a perpetual motion machine of the second kind are very clear. You have to specify the machine and demonstrate that it will produce work continually forever.

480. I have become convinced that the isothermal hypothesis, although correct as an approximation, is theoretically true only in the limit….
(referring to the following from tallbloke):
It is from the thus-obtained Velasco et al. Equations 5 and 6 that they claim to obtain their Equation 8 for temperature as a function of altitude, and it is that equation that seems to me not to jibe with any significant lapse rate: although it does have temperature fall with altitude, the drop, if my calculations are correct, is negligible.
Does anyone see where the authors or I went wrong here?

Sure. You and the authors seem to fail to appreciate the fact that any lapse rate in equilibrium violates the second law of thermodynamics.
You obviously understand thermo and some stat mech, so surely you understand Willis (and my own, independent) argument. In your imagined atmosphere, with hotter temperatures anywhere that are maintained by e.g. gravity as a steady state, if you run a thermally insulated conductor from the hot to the cold, what will happen, Joe? How long will it happen?
That’s right, heat will flow (to equalize the temperature difference) because that’s what heat does — it flows from hot to cold through any material that can conduct heat. It doesn’t matter if the gas parcels in thermal contact with the ends of the “heat pipe” are at the top or bottom of a vertical column of air or running between two adiabatically isolated containers of air at different temperatures and pressures, heat will flow from the hot side to the cold side. If Velasco is predicting that the gas will spontaneously separate into hot and cold reservoirs, well, I don’t think it is possible to imagine a more pure example of a violation of the second law, can you?
The beauty of the laws of thermodynamics is that it no longer matters if one can find the precise error made by Velasco in a complicated stat mech analysis. In all probability it involves including momentum or failing to achieve local equilibrium in the first place — ultimately what he is asserting is that there is a failure of detailed balance (because detailed balance leads to isothermal equilibrium). But no matter — heat will not flow forever in an isolated system, will it? And yet, if the top and the bottom of the container maintain themselves at different temperatures, it will, the instant you provide an alternative pathway for heat to flow in the still isolated system.
If Velasco has somehow proven that gravity acts as Maxwell’s Demon — which is precisely what this is — then either he deserves a Nobel Prize, for proving that the second law is openly violated in the Universe and at the same time solving our energy crisis as we can start building 100% efficient perpetual motion machine of the second kind heat engines, engines that just recycle heat into work indefinitely, or he deserves to be instantly ignored until he goes back and finds his own mistake. Personally, I wouldn’t dare to publish a paper that asserted that the second law is violated, that gravity acts like Maxwell’s Demon in any atmosphere ideal or real, because I know that if I somehow got that as a conclusion, my work would almost certainly be incorrect. I’d be just as leery of publishing something with an error in units, or that violated energy conservation.
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481. Richard M;
This was the same argument Joel tried to use against me back in Ira’s thread. It’s unfortunate that they are willing to discard what may very well be a valid correlation by simply waving their hands.>>>
Frankly I am disgusted. Equation 8 in N&Z’s article has two variables, and anyone who can read can see that. All their results are calculated using THAT equation. Trying to represent it as having four variables by pointing to an intermediate step is an outright lie.
Willis, please. Read the effing Equation 8 for yourself and set the record straight.

482. Hans Jelbring says:

Robert Brown says:
January 21, 2012 at 7:24 am
“Here’s a shorter elevator speech:
If there is a temperature gradient between two parts of a system, net heat flows from the warmer part to the cooler part. If there is net heat flow within the system, it is not in equilibrium.
Wow, so perfectly correct! Two laws of thermodynamics (0 and 2). Done./rgb”
Perfectly wrong since you refuse to include gravity in the system you are treating. Since you now are informed that the Zeroth Law doesn´t work in this situation it seems that you are practising “willful ignorance” which does not belong to scientific methods.
Best
Hans Jelbring

483. pochas says:

tallbloke says:
January 21, 2012 at 7:10 am
“Assuming your A and B have at least some dimension, then a thermal gradient across them would mean that the top surface of A will be at the same temperature as the bottom surface of B where they contact. Therefore no heat will flow. Even so, the average temperature of the whole of body A will be higher than that of B. QED.”
Tallbloke, please bear in mind that for any parcel that leaves an air layer, another parcel must enter to conserve mass, and the parcel that enters has an equal likelihood of expanding on entry as compressing. Thus on balance the number of parcels that expand when entering the layer must equal the number of parcels that compress when entering, leaving no net change in the energy content of the layer, and no opportunity for perpetual motion on account of the adiabatic process. However, there is still conduction, which will eventually remove any temperature gradient that exists in the absence of an external source of power. It should be clear that an external source of power is required to develop the adiabatic temperature profile and in our neighborhood the sun does the trick.

484. Can somebody please conceive this fact; Energy cabn be also employed, not just conserved.
Add kinetic energy to matter and the E does not equal mc/2.

OK, once again we have a case of “get an intro physics textbook and read it before stating things that you don’t understand and that are in any event incorrect”.
First of all, energy cannot be “employed”. Free energy can be employed, then it turns into heat. Heat cannot be employed to make work unless there are two thermal reservoirs at different temperatures. If you want to discuss this, please learn the laws of thermodynamics. If you want to assert that the laws of thermodynamics are incorrect, all I can say is don’t be silly! That may not stop you from being silly, but it should.
Second, E = \gamma m c^2 (for an isolated massive particle moving at constant speed in an inertial frame). This includes the kinetic energy. In fact, the low-velocity “usual” form of the KE is the first non-constant term in a binomial/Taylor series expansion of \gamma m c^2. A common way of asserting this is to include the \gamma in the m and say that particles with kinetic energy are more massive. This is, in fact, the case — a hot object is indeed more massive than the same object when cold.
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485. Extend the column or cylinder to TOA and you have a mechanism to lose the top layer to space fairly rapidly, and by logical extension, the whole atmosphere.. Some disconnect with reality here?
Not at all. Learn about “escape velocity”. This is how the Earth does, gradually, lose atmosphere. It just takes a long, long time for the heavier molecules at the average temperature of the Earth.
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486. Robany says:

In the event that anyone read my previous post, I should point out the following: Stygia is a perpetual motion machine. It was defined as such by Willis himself. A perfectly insulating, perfectly reflective shell defines a closed, perfectly lossless system: the very definition of a perpetual motion machine.
The average temperature of Stygia must drop as light is generated but there will be a point where the energy reabsorption (and heating) of the planet will exactly balance the energy extracted by the heat engine. Stygia will be light but colder than if it was dark.
In answer to the charge that we could build energy sources that extract energy from a temperature gradient in the atmosphere. The energy drained from the atmosphere is replenished by insolation. Well known parallels would be the photovoltaic cell or wind turbine. Extracting energy directly or indirectly from the energy of insolation. Not very efficient I grant you but that’s why we don’t want to rely on renewables.

487. BenAW;
What both approaches are neglecting is that the earths surface consist mostly of oceans,
70% area, minimum 3 km deep and a temperature on average of +2C, already 20K higher
than the blackbody temperature the GHE uses when the sun has heated the blackbody.>>>>
I recommend BenAW’s comment upthread to everyone who demands an explanation of surface temperature that is higher than blackbody via a means other that back radiation. The earth surface is ALREADY above the blackbody temp, all the sun has to do is MAINTAIN it, and there is sufficient energy from the sun to do that while also satisfying the laws of thermodynamics. you cannot arrive at that conclusion however unless you first properly apply SB Law instead of starting off with mind bogglingly WRONG averages of a set of variables that CANNOT be compared via averages.
BenAW, the one quibble I have with your comment is that N&Z missed this. My reading of N&Z is that it is founded upon this (amongst several other things).

488. Hans Jelbring says:

Robert Brown says:
January 21, 2012 at 7:39 am
The problem is that GHGs and back radiation does not explain the vertical temperature of the atmosphere. The inescapable conclusion of this is that the GHG model is not capable of explaining our atmosphere and that there is