Guest Post by Willis Eschenbach
A couple of apparently related theories have been making the rounds lately. One is by Nikolov and Zeller (N&Z), expounded here and replied to here on WUWT. The other is by Hans Jelbring, discussed at Tallblokes Talkshop. As I understand their theories, they say that the combination of gravity plus an atmosphere without greenhouse gases (GHGs) is capable of doing what the greenhouse effect does—raise the earth at least 30°C above what we might call the “theoretical Stefan-Boltzmann (S-B) temperature.”
So what is the S-B temperature, theoretical or otherwise?
A curious fact is that almost everything around us is continually radiating energy in the infrared frequencies. You, me, the trees, the ocean, clouds, ice, all the common stuff gives off infrared radiation. That’s how night-vision goggles work, they let you see in the infrared. Here’s another oddity. Ice, despite being brilliant white because it reflects slmost all visible light, absorbs infrared very well (absorptivity > 0.90). It turns out that most things absorb (and thus emit) infrared quite well, including the ocean, and plants (see Note 3 below). Because of this, the planet is often treated as a “blackbody” for IR, a perfect absorber and a perfect emitter of infrared radiation. The error introduced in that way is small for first-cut calculations.
The Stefan-Boltzmann equation specifies how much radiation is emitted at a given temperature. It states that the radiation increases much faster than the temperature. It turns out that radiation is proportional to absolute temperature to the fourth power. The equation, for those math inclined, is
Radiation = Emissivity times SBconstant times Temperature^4
where the Stefan-Boltzmann constant is a tiny number, 0.0000000567 (5.67E-8). For a blackbody, emissivity = 1.
This “fourth-power” dependence means that if you double the absolute temperature (measured in kelvins), you get sixteen (2^4) times the radiation (measured in watts per square metre, “W/m2”). We can also look at it the other way, that temperature varies as the fourth root of radiation. That means if we double the radiation, the temperature only goes up by about 20% (2^0.25)
Let me call the “theoretical S-B temperature” the temperature that an evenly heated stationary blackbody planet in outer space would have for a given level of incoming radiation in W/m2. It is “theoretical”, because a real, revolving airless planet getting heated by a sun with the same average radiation will be cooler than that theoretical S-B temperature. We might imagine that there are thousands of mini-suns in a sphere around the planet, so the surface heating is perfectly even.
Figure 1. Planet lit by multiple suns. Image Source.
On average day and night over the planetary surface, the Earth receives about 240 W/m2 of energy from the sun. The theoretical S-B temperature for this amount of radiation (if it were evenly distributed) is about -18°C, well below freezing. But instead of being frozen, the planet is at about +14°C or so. That’s about thirty degrees above the theoretical S-B temperature. So why isn’t the planet a block of ice?
Let me take a short detour on the way to answering that question in order to introduce the concept of the “elevator speech” to those unfamiliar with the idea.
The “elevator speech” is simply a distillation of an idea down to its very basics. It is how I would explain my idea to you if I only had the length of an elevator ride to explain it. As such it has two extremely important functions:
1. It forces me to clarify my own ideas on whatever I’m discussing. I can’t get into handwaving and hyperbole, I can’t be unclear about what I’m claiming, if I only have a few sentences to work with.
2. It allows me to clearly communicate those ideas to others.
In recent discussions on the subject, I have been asking for that kind of “elevator speech” distillation of Jelbring’s or Nikolov’s ideas, so that a) I can see if whoever is explaining the theory really understands what they are saying and, if so, then b) so that I can gain an understanding of the ideas of Jelbring or Nikolov to see if I am missing something important.
Let me give you an example to show what I mean. Here’s an elevator speech about the greenhouse effect:
The poorly-named “greenhouse effect” works as follows:
• The surface of the earth emits energy in the form of thermal longwave radiation.
• Some of that energy is absorbed by greenhouse gases (GHGs) in the atmosphere.
• In turn, some of that absorbed energy is radiated by the atmosphere back to the surface.
• As a result of absorbing that energy from the atmosphere, the surface is warmer than it would be in the absence of the GHGs.
OK, that’s my elevator speech about why the Earth is not a block of ice. Note that it is not just saying what is happening. It is saying how it is happening as well.
I have asked, over and over, on various threads, for people who understand either the N&Z theory or the Jelbring theory, to give me the equivalent elevator speech regarding either or both of those theories. I have gotten nothing scientific so far. Oh, there’s the usual handwaving, vague claims of things like ‘the extra heat at the surface, is just borrowed by the work due to gravity, from the higher up regions of the atmosphere‘ with no mechanism for the “borrowing”, that kind of empty statement. But nothing with any meat, nothing with any substance, nothing with any explanatory value or scientific content.
So to begin with, let me renew my call for the elevator speech on either theory. Both of them make my head hurt, I can’t really follow their vague descriptions. So … is anyone who understands either theory willing to step forward and explain it in four or five sentences?
But that’s not really why I’m writing this. I’m writing this because of the claims of the promoters of the two theories. They say that somehow a combination of gravity and a transparent, GHG-free atmosphere can conspire to push the temperature of a planet well above the theoretical S-B temperature, to a condition similar to that of the Earth.
I hold that with a transparent GHG-free atmosphere, neither the hypothetical “N&Z effect” nor the “Jelbring effect” can possibly raise the planetary temperature above the theoretical S-B temperature. But I also make a much more general claim. I hold it can be proven that there is no possible mechanism involving gravity and the atmosphere that can raise the temperature of a planet with a transparent GHG-free atmosphere above the theoretical S-B temperature.
The proof is by contradiction. This is a proof where you assume that the theorem is right, and then show that if it is right it leads to an impossible situation, so it cannot possibly be right.
So let us assume that we have the airless perfectly evenly heated blackbody planet that I spoke of above, evenly surrounded by a sphere of mini-suns. The temperature of this theoretical planet is, of course, the theoretical S-B temperature.
Now suppose we add an atmosphere to the planet, a transparent GHG-free atmosphere. If the theories of N&K and Jelbring are correct, the temperature of the planet will rise.
But when the temperature of a perfect blackbody planet rises … the surface radiation of that planet must rise as well.
And because the atmosphere is transparent, this means that the planet is radiating to space more energy than it receives. This is an obvious violation of conservation of energy, so any theories proposing such a warming must be incorrect.
Q.E.D.
Now, I’m happy for folks to comment on this proof, or to give us their elevator speech about the Jelbring or the N&Z hypothesis. I’m not happy to be abused for my supposed stupidity, nor attacked for my views, nor pilloried for claimed errors of commission and omission. People are already way too passionate about this stuff. Roger Tattersall, the author of the blog “Tallbloke’s Talkshop”, has banned Joel Shore for saying that the N&Z hypothesis violates conservation of energy. Roger’s exact words to Joel were:
… you’re not posting here unless and until you apologise to Nikolov and Zeller for spreading misinformation about conservation of energy in their theory all over the blogosphere and failing to correct it.
Now, I have done the very same thing that Joel did. I’ve said around the web that the N&Z theory violates conservation of energy. So I went to the Talkshop and asked, even implored, Roger not to do such a foolish and anti-scientific thing as banning someone for their scientific views. Since I hold the same views and I committed the same thought-crimes, it was more than theoretical to me. Roger has remained obdurate, however, so I am no longer able to post there in good conscience. Roger Tallbloke has been a gentleman throughout, as is his style, and I hated to leave. But I did what Joel did, I too said N&Z violated conservation of energy, so in solidarity and fairness I’m not posting at the Talkshop anymore.
And more to the point, even if I hadn’t done what Joel did, my practice is to never post at or even visit sites like RealClimate, Tamino’s, and now Tallbloke’s Talkshop, places that ban and censor scientific views. I don’t want to be responsible for their page views counter to go up by even one. Banning and censorship are anathema to me, and I protest them in the only way I can. I leave them behind to discuss their ideas in their now cleansed, peaceful, sanitized, and intellectually sterile echo chamber, free from those pesky contrary views … and I invite others to vote with their feet as well.
But I digress, my point is that passions are running high on this topic, so let’s see if we can keep the discussion at least relatively chill …
TO CONCLUDE: I’m interested in people who can either show that my proof is wrong, or who will give us your elevator speech about the science underlying either N&K or Jelbring’s theory. No new theories need apply, we have enough for this post. And no long complicated explanations, please. I have boiled the greenhouse effect down to four sentences. See if you can match that regarding the N&K or the Jelbring effect.
w.
NOTE 1: Here’s the thing about a planet with a transparent atmosphere. There is only one object that can radiate to space, the surface. As a result, it is constrained to emit the exact amount of radiation it absorbs. So there are no gravity/atmospheric phenomena that can change that. It cannot emit more or less than what it absorbs while staying at the same temperature, conservation of energy ensures that. This means that while the temperature can be lower than the theoretical S-B temperature, as is the case with the moon, it cannot be more than the theoretical S-B temperature. To do that it would have to radiate more than it is receiving, and that breaks the conservation of energy.
Once you have GHGs in the atmosphere, of course, some of the surface radiation can get absorbed in the atmosphere. In that case, the surface radiation is no longer constrained, and the surface is free to take up a higher temperature while the system as a whole emits the same amount of radiation to space that it absorbs.
NOTE 2: An atmosphere, even a GHG-free atmosphere, can reduce the cooling due to uneven insolation. The hottest possible average temperature for a given average level of radiation (W/m2) occurs when the heating is uniform in both time and space. If the total surface radiation remains the same (as it must with a transparent atmosphere), any variations in temperature from that uniform state will lower the average temperature. Variations include day/night temperature differences, and equator/polar differences. Since any atmosphere can reduce the size of e.g. day/night temperature swings, even a transparent GHG-free atmosphere will reduce the amount of cooling caused by the temperature swings. See here for further discussion.
But what such an atmosphere cannot do is raise the temperature beyond the theoretical maximum average temperature for that given level of incoming radiation. That’s against the law … of conservation of energy.
NOTE 3: My bible for many things climatish, including the emissivity (which is equal to the absorptivity) of common substances, is Geiger’s The Climate Near The Ground, first published sometime around the fifties when people still measured things instead of modeling them. He gives the following figures for IR emissivity at 9 to 12 microns:
Water, 0.96 Fresh snow, 0.99 Dry sand, 0.95 Wet sand, 0.96 Forest, deciduous, 0.95 Forest, conifer, 0.97 Leaves Corn, Beans, 0.94
and so on down to things like:
Mouse fur, 0.94 Glass, 0.94
You can see why the error from considering the earth as a blackbody in the IR is quite small.
I must admit, though, that I do greatly enjoy the idea of some boffin at midnight in his laboratory measuring the emissivity of common substances when he hears the snap of the mousetrap he set earlier, and he thinks, hmmm …
I think we should keep in mind that emission and absorption are two sides of the same coin; one becomes the other on time reversal. This is why those photons most likely to be emitted by a carbon dioxide molecule are also those most likely to be absorbed by another CO2 molecule. If an atmosphere has a method for absorbing photons, then it has a method for emitting those same photons.
If a theoretical non-greenhouse gas has a optical wavelength absorption band, then it will both absorb solar energy and emit terrestrial energy by this mechanism. Such a gas would continue to absorb heat from the sun until it reaches a temperature sufficient to excite emission of the same energy flow back to outer space or until this atmosphere becomes so hot that it all escapes to outer space.
The problem with the gravitational heating theory is that it does not provide any mechanism to continuously extract or reflect an average 156 W/m² from a hypothetical average 396 W/m² radiant energy flow of a typical GHG warmed surface so that only the allowed average 240 W/m² actually escapes to outer space. As these are average energy calculations, any reference to surface temperatures or temperature variations are irrelevant. These averages apply over time as well as space.
AnonyMoose says:
January 17, 2012 at 5:59 am
Thanks, Anony. Actually, that’s not a bad matchbook speech for the theories, it’s like an elevator speech only shorter. This one was that “gravity is being credited with continuously creating heat“. I do believe that both the Jelbring and the N&Z models have that in common, and I think that is why the authors are unwilling to give a concise, clear description of the models, as that would become obvious.
w.
Leonard Weinstein says:
January 17, 2012 at 8:27 am
Thank you for putting that more clearly than I could have. All things can emit thermal radiation. But at our normal temperatures, some gases emit so little radiation that for all practical purposes they can be considered perfectly transparent to IR. They will eventually radiate to zero K, as Anna says … but it may take the life of the universe to do so.
w.
Bart,
If I calculate absorptivity = 1-reflectivity according to the Fresnel equations using an index of refraction for water of 1.333, I can indeed calculate an average emissivity of 0.82. But the emission to the surrounding hemisphere decreases with cosine(θ). The effect of increasing area is not sufficient to cancel this effect. When I correct the emission for emissivity and integrate over the hemisphere, the effective emissivity is 0.93.
Willis now agrees that the atmosphere will be isothermal. Heat can only accumulate in the upper atmosphere until the atmosphere is isothermal. It won’t conduct after that. You can’t have a constant reduction of temperature with altitude and also have continuous heat accumulation. Heat accumulation requires an increase in temperature.
As for ionization, oxygen has the lowest ionization energy of the three major components of the atmosphere at 1314 kJ/mole. For oxygen to be 0.1% ionized thermally requires a temperature of 22,900K or interaction with a 90nm wavelength photon for an individual molecule. 90nm photons don’t penetrate very far and the molecules won’t stay ionized unless the mean free path is long, i.e. higher than 100 km. Your glow discharge and/or lightning is absurd.
For those who think that all things emit thermal radiation at normal earth temperatures, please give us the amount. Take argon as an example. How much thermal radiation does it emit at say 10°C? Come back with the absorption lines for argon in the normal IR range.
I say it absorbs none. Zero. It only absorbs or emits in one way, through electron transitions, and that takes a whole bunch of energy to force one of those, and it doesn’t happen in the IR. Because argon is a monoatomic gas, the atoms of argon have no mechanical way to absorb or emit energy through bending or stretching. There is no physical way for the atoms to absorb or emit energy, an atom of argon is a little ball and the energy simple can’t interact with it except in high-energy electron transitions.
Regards,
w.
Bart says:
January 17, 2012 at 3:20 pm
Ok, but how does that allow the surface temperature to be higher with an atmosphere than without in the thought experiment?
How does that allow the temperature to rise at least thirty degrees or so (or even half a degree) without increasing surface radiation?
The point of starting from the uniformly heated condition is that there is no warmer arrangement for a given radiation level. For any radiation level, isothermal conditions give you the highest average temperature. Because of that, any change in the arrangement of the thermal energy will give a lower temperature.
All the best,
w.
Bart,
The Laplacian of the temperature field can be zero if the temperature is constant with respect to r, θ and φ, i.e. no gradient. But unless B = 0 in your solution, there is a gradient in r and the Laplacian of T can’t be zero. If B is zero, then A isn’t zero, but is equal to the surface temperature.
I think that is a total misreading of the theory. It is not saying gravity is continuously creating heat. Any more than someone thinks a compressed spring constantly produces energy. It only stores energy that already is in the system.
It is saying that an atmosphere in a gravity field due to ideal gas laws must develop a temperature gradient due to its lapse rate. The lower levels of the atmosphere will be cooler than the upper layer of the atmosphere. Therefore when the upper levels of the atmosphere reach a temperature where they lose heat at the same rate as additional heat is added to the system (note I did not say lose heat by IR radiation) then the lower levels of the atmosphere will be warmer.
To use your example, lets suppose the atmosphere cannot radiate a single photon in the IR. That does not preclude other mechanisms of losing energy. What those other mechanisms are does not matter as long as there is some method to lose energy. The atmosphere will do what ever it has to in order to reach those conditions to loose the excess energy.
Lets further suppose that all paths of radiation energy loss are closed. No loss of energy by visible light radiation due to florescence, no electrical discharge or electron emission or gamma ray emission or radio wave all those paths are closed. What would happen?
Simple — the atmosphere would continue to heat up but it would still have a lapse rate At some point high above the surface the temperature would rise high enough so that the atoms can achieve escape velocity (remember that due to this thermal expansion they are very high above the planet so gravity is reduced). At that point with all electromagnetic paths closed the atmosphere would still lose heat to interstellar space by mass transport as gases (like the solar wind) continuously blew off into space.
The theory does not speculate on the exact mechanism of energy loss, only that in a real atmosphere above a planet with a gravity field there must be a temperature gradient with altitude (we commonly call the lapse rate) due to the ideal gas laws.
If you can propose a condition where that is not the case, then you are invalidating the ideal gas laws, or your model is physically impossible.
That gradient, then forces the lower levels of the atmosphere to be warmer than the effective radiation temperature (or other heat loss mechanism) that eventually achieves thermal balance with the incoming radiation.
At least that is my take on it.
Bart says:
January 17, 2012 at 4:22 pm
Hey, I had to fight hard to understand that, and I just got there. It’s also what the textbooks say. Not sure I can defend it too vigorously, but my numbers say if you have air in a container, whether in a gravity field or not, at equilibrium it is isothermal.
As to your further explanation that ended with T = B/r, where r is the radius, you’ll have to explain that. I think you are saying the temperature varies because of the shape of the container, but it’s far from clear.
Thanks,
w.
Anything is possible says:
January 17, 2012 at 4:45 pm
So they have invalidated the S-B law. You’re right, I am looking forward to Part 1.
w.
Correction — typo:
The lower levels of the atmosphere will be cooler than the upper layer of the atmosphere.
should read:
The lower levels of the atmosphere will be warmer than the upper layer of the atmosphere.
Larry
Stephen Wilde says:
January 17, 2012 at 4:46 pm
Stephen, thanks for the post. The difficulty is in your claim that “since there are more molecules per unit volume at the bottom they will absorb proportionately more of the incoming energy per unit volume and become warmer than the molecules where the energy per unit volume is lower”.
In general, the relation between the flow of energy, mass, and temperature is
Q = m c ∆T
where Q is the energy, m is the mass, ∆T is the change in temperature, and c is the specific heat of the substance. Rearranging, we get:
∆T = Q / (m c)
My question for you is this. If you double the energy and you double the mass, what happens to the temperature change?
It doesn’t change at all. So if, as you say, there are “more molecules per unit volume at the bottom they will absorb proportionately more of the incoming energy per unit volume”, if there is double the mass and it absorbs double the energy, the temperature change will be the same as if there is half the mass absorbing half the energy.
Finally, temperature stops rising and heat stops being absorbed regardless of mass when the objects are at the same temperature.
w.
Bart says:
January 17, 2012 at 4:53 pm
So your contention is that the surface will warm the atmosphere until it is much warmer than the surface? I don’t see how it could, that’s pushing heat uphill.
I fear that the heat transfer will cease entirely as soon as the atmosphere warms to the temperature of the surface. How can the surface cause the atmosphere to warm past that?
w.
Bart says: January 17, 2012 at 4:53 pm
That’s the problem, Willis. In your thought experiment, you have no outlet for radiation of the heat conducted to the atmosphere. As a result, your atmosphere heats, and heats, and heats.
============
A non GHG neither emits nor receives energy by absorption
A non GHG can only heat by conduction
A Non GHG Will pass downward solar radiation and upward LW radiation without hindrance and without heating
The surface is heated by the solar radiation.
It is cooled by LW radiation. when incoming radiation = out going radiation thermal equilibrium will result. This equality only occurs at one temperature for fixed incoming radiation and surface albedo.
The non-GHG will be heated by the surface by conduction only – initially cooling the surface. There is nowhere for the heat to go – non-GHGs do not radiate and there is nothing to conduct to in space.
Eventually the non-GHG will reach the same temperature as the planet surface and heating by conduction will cease. The non-ghg will get no hotter than the surface.
The surface will now be surrounded by hot conductive gas which does not radiate but also does not stop surface radiation escaping (i.e. it does not act as a blanket retaining the surface heat,
So we still have the same radiation arriving at the surface and the same leaving. The albedo is the same. The temperature at the surface therefore is the same with and without Non GHGs
hotrod (larry L) says:
January 17, 2012 at 5:52 pm
I do believe that Jelbrings theory says that, but I don’t know about N&Z.
If gravity could do that, if gravity alone could split the atmosphere into warm and cool, then we could get work out of the temperature difference … forever. With no input of energy.
Would be nice …
w.
Spector says:
January 17, 2012 at 5:04 pm
The problem with the gravitational heating theory is that it does not provide any mechanism to continuously extract or reflect an average 156 W/m² from a hypothetical average 396 W/m² radiant energy flow of a typical GHG warmed surface so that only the allowed average 240 W/m² actually escapes to outer space.”
What that means is not that the GHGs heated the surface above what it otherwise would have been. Rather, it means it is maintaining it that much cooler below what it otherwise would have been.
DeWitt Payne says:
January 17, 2012 at 5:30 pm
“The effect of increasing area is not sufficient to cancel this effect.”
In fact, it increases faster. Do the calculations.
When I correct the emission for emissivity and integrate over the hemisphere, the effective emissivity is 0.93.”
Still a lot less than 0.99. And, this is in calm seas. When you do the right calculation, it will be even worse.
Willis now agrees that the atmosphere will be isothermal.”
…So?
“You can’t have a constant reduction of temperature with altitude and also have continuous heat accumulation.”
You appear to be mixing fluxes in space and in time.
“Your glow discharge and/or lightning is absurd.”
On planet Earth. Not on Willis’ thought experiment world. You haven’t been keeping up. I suggest you read my latest contributions to the discussion.
Willis Eschenbach says:
January 17, 2012 at 5:47 pm
The point of starting from the uniformly heated condition is that there is no warmer arrangement for a given radiation level.”
Nope. Been there, done that. See last comment here.
DeWitt Payne says:
January 17, 2012 at 5:51 pm
“But unless B = 0 in your solution, there is a gradient in r and the Laplacian of T can’t be zero.”
Aye yi yi.
Willis Eschenbach says:
January 17, 2012 at 5:55 pm
“It’s also what the textbooks say.”
The textbooks are looking at flat geometry. This is a spherical distribution.
“As to your further explanation that ended with T = B/r, where r is the radius, you’ll have to explain that.”
Come ON, you guys. Surely, you’ve solved the LaPlace equation somewhere along the way in your studies? Voltage from a point charge? Gravitational potential from a point mass? Ring a bell?
Willis Eschenbach says:
January 17, 2012 at 6:12 pm
“So your contention is that the surface will warm the atmosphere until it is much warmer than the surface?”
How do you know how warm the surface is? It is continually warming, too. There is no equilibrium until the atmosphere finds an outlet for its stored heat. At that point, you will find everything balances.
It does on earth we call that work thunderstorms and winds.
Larry
“Erl Happ says:
January 17, 2012 at 8:04 am
Willis says: “I hold it can be proven that there is no possible mechanism involving gravity and the atmosphere that can raise the temperature of a planet with a transparent GHG-free atmosphere above the theoretical S-B temperature.”
That’s a valid statement but it does not invalidate the crux of what N and Z are telling us.”
No it’s not a valid statement.
Main thing proven is the “theoretical S-B temperature” is wrong.
To be clear is hasn’t proven that T cubed times .0000000567 equals watts per square meter is incorrect.
But rather T cubed times .0000000567 divided by 4 which is what Willis is saying is “theoretical S-B temperature” is wrong.
If earth had million star which at earth distance has solar flux of 240 watts per square meter. To determine temperature of planet you do not cube 255 and times this by .0000000567 and divide it by 4. If you did this the “theoretical S-B temperature” would 60 watts per square meter. Which is
180 K. therefore the “theoretical S-B temperature” would indicate that million sun would heat a planet to 180 K. Whereas “logical sense” would suggest it’s 255 K- because sunlight is coming from all directions and you don’t need to divide by 4. But if you do this “even though you don’t need to” you get the wrong answer.
In addition you get wrong answer if subtract Bond albedo to determine planet’s temperature. It’s possible a highly reflective surface with planet with million sun would same temperature [and may be warmer].
In other words regardless of color or if planet was liquid mercury and/or cover with clouds the temperature will be around 255 K
Hi Willis –
Thinking in terms of average kinetic energy also makes ice sublimation at -20 C sound impossible. Yet, individual frozen water molecules are melting, reaching the boiling point and escaping as water vapor.
Argon can absorb energy via collision (conduction). True, it won’t undergo electronic excitation until it has surpassed a certain high threshold. However, a millions suns might suffice, no?
Even in the condition of isothermal equilibrium, with no difference in temperature between planet and atmosphere, and no difference in temperature within the atmosphere in the vertical or lateral profile, there are still vast differences in kinetic energy between individual particles.
Enormous numbers of unpredictable collisions and interactions with random quantum vacuum fluctuations, etc. will eventually deal low temperature argon a royal-flush, the acquisition of the necessary additional energy for electronic excitation and upon relaxation to a lower state, the emission of a high energy photon. IMO, this continuing energy loss would set up a (possibly weak) convective circulation of surface heat removal resulting in lowered surface emission temperature.
This story is not complete, but a single counter-example. For more, perhaps Anna V. will help out.
bi2hs
All of the questions people might have for me have been answered in earlier posts. There’s really no doubt about it. So-called GHGs cool the atmosphere, just like the astrophysicists say they will. If I were asked to choose between believing an astrophysicist or a climate scientist, I’m pretty sure where I’d place my bets.
For people still having problems, I suggest you read the preceding posts carefully until the light bulb goes off for you, too. I’m calling it a night.
A few reminders and notes to ponder:
Kirchoff’s law says SB places an upper bound on energy radiated given temperature. That means it places a lower bound on temperature given energy. SB does not hold until you are at equilibrium.
If one insists on believing that GHGs which radiate in the IR elevate surface temperatures, how much higher would the temperature be elevated by a GHG radiating in the UV?
The gradient of the function 1/r, where r = sqrt(x^2+y^2+z^2), in Cartesian coordinates is the vector (x/r,y/r,z/r). What is the divergence? I.e., what is d(x/r)/dx + d(y/r)/dy + d(z/r)/dz? Hint: ZERO.
Murray Gell-Mann is quoted as saying of physics: “Everything not forbidden is compulsory.” It’s a very useful saying which can help guide you to truth.
“hotrod (larry L) says:
January 17, 2012 at 5:52 pm
AnonyMoose says:
January 17, 2012 at 5:59 am
…
I had missed that gravity was being credited with continuously creating heat.
I think that is a total misreading of the theory. It is not saying gravity is continuously creating heat. Any more than someone thinks a compressed spring constantly produces energy. It only stores energy that already is in the system.
It is saying that an atmosphere in a gravity field due to ideal gas laws must develop a temperature gradient due to its lapse rate. The lower levels of the atmosphere will be cooler than the upper layer of the atmosphere. Therefore when the upper levels of the atmosphere reach a temperature where they lose heat at the same rate as additional heat is added to the system (note I did not say lose heat by IR radiation) then the lower levels of the atmosphere will be warmer.
To use your example, lets suppose the atmosphere cannot radiate a single photon in the IR. That does not preclude other mechanisms of losing energy. What those other mechanisms are does not matter as long as there is some method to lose energy. The atmosphere will do what ever it has to in order to reach those conditions to loose the excess energy.
Lets further suppose that all paths of radiation energy loss are closed. No loss of energy by visible light radiation due to florescence, no electrical discharge or electron emission or gamma ray emission or radio wave all those paths are closed. What would happen?”
You same situation as a million suns.
The sun is only capable of heat an object to a certain temperature.
This temperature is somewhere near the highest temperatures on lunar surface.
Around 120 C [390 K]. 390 cubed times .0000000567 is 1311.7.
If Earth had a million suns it’s surface temperature would be 120 C.
Though it should noted that at higher elevations it would be cooler than 120 C.
Mt everest [8850 meters high] would be cooler- if assume 6 C per 1000 meters
it would be around 67 C. Even with a million suns, the oceans would not boil, but Ocean evaporation would be quite high.
If you don’t have million suns and rather as you say not heat could leave earth, the difference
between that and million sun is it would take longer to heat the entire planet to 120 C- a million sun may do this in 1000 years and the one sun might take a million years.
Getting to 80 C would pretty quick but nearer it gets to 120 C the slower the warming
“The gradient of the function 1/r, where r = sqrt(x^2+y^2+z^2), in Cartesian coordinates is the vector (x/r,y/r,z/r)”
Oops. That’s the gradient of r. The gradient of 1/r is -1/r^2 times that. And, the divergence to calculate is d(x/r^3)/dx + d(y/r^3)/dy + d(z/r^3)/dz = 0.
from – A First Course in Atmospheric Radiation: Second Edition, by Grant W. Petty
most modes of energy storage at the molecular level and smaller are quantized. That is to say, a given molecule cannot have just any vibrational energy, but rather only one of a discrete set of energy levels E o , El, , Eco permitted by the laws of quantum mechanics applied to that particular molecule. The same principle applies to other modes of energy storage, such as that associated with molecular rotation and electron excitation. Only the translational kinetic energy of molecules and other unbound particles is unquantized.
At ordinary atmospheric temperatures, collisions between molecules are very rarely energetic enough to kick electrons into excited states. Those few that do briefly find themselves in an excited state, for whatever reason, usually give up their energy again in the course of subsequent collisions without emitting a photon.
There are therefore extremely few electrons found naturally in excited states and even fewer opportunities for the spontaneous emission of photons due to electronic transitions back to the ground state. This fact is of course consistent with the sharp fall-off in thermal emission at the short wavelength end of the Planck function.
When electron orbits in atmospheric molecules are found in an excited state, it is usually because of the absorption of an incoming photon with the right energy, usually one of solar origin. As for rotational and vibrational transitions, we therefore expect to find discrete absorption lines associated with each allowed transition to higher electronic orbital states
=====
O2 has absorption up to 250nm (uv end) In the earths atmosphere this is mainly removed by )3 etc. There is a further rotation exitation in the 10s of GHz region. (this is not relevant with the solar spectrum)
I’m a lawyer and read this website so that I can speak to issues from a different perspective than that of most of my peers. I really need that elevator speech. So, could you all stop sniping and make an attempt to attain that goal. Thanking you in advance for your cooperation – as we say in the legal profession.
Hello Willis,
I posted this a while back, but it must have gone into the chronosynclastic infundibulum. I have not read the mentioned papers, and have not read all of the comments. I may be repeating what has already been posted.
1. I agree with you that the embodiment of the planet with many suns and a transparent atmosphere will be at the S-B temperature. This includes the surface and the gases.
2. Let us suppose that the suns can be turned up in brightness by a step DELTA_BRIGHTNESS. The surface and gas column will equilibrate to the new S-B temperature in a time T_heat by conduction from the surface to the gases then convection to the rest of the column.
3. Let us now turn the suns back to their original brightness. The surface will eventually go back to the original S-B temperature and the gas column will cool to the new S-B temperature by conduction. Convection will be inoperative. Time T_cool will be much longer than T_heat, but will eventually reach the original S-B temperature.
4. Let us now turn the suns brightness up and down by a step DELTA_BRIGHTNESS such that the cycle time is shorter than T_cool. The atmospheric column temperature will approach the upper S-B surface temperature as a limit. The surface temperature will approach the lower S-B temperature as a limit. The biggest temperature difference will be between the surface and the upper atmosphere.
5. For the electronically minded this can be modeled by a diode (convection) with a resistor in parallel (back conduction) feeding a capacitor (energy storage in the column). The diode (one way valve) is produced by the lack of downward convection, since the gas column does not radiate.
6. What would it take to reverse the scenario (diode)? If we placed the surface in the upper atmosphere, there would be only downward convection of cooled gases. The gas column would approach the lower S-B temperature as a limit.
7. Yes this is a matter of some gravity. Without gravity there would be no convection, etc.
Please feel free to pick the explanations apart. Why do I get the funny feeling that the audience is being trifled with, especially in light of the title of the post, and all of the odd behaviour?