A Matter of Some Gravity

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 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 …

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michael hammer

Willis, I agree with amonst everything you said with one exception. I question the emissivity of fresh snow. Yes cetainly water and ice have IR emissivities very close to 1 but fresh snow is a mixture of ice and air with each “layer” or crystal a few to a few 10’s of microns thick. each transition of refractive index gives rise to reflections and the repeated and rapid change of refractive index results in a highly reflective surface. That is also what makes crazed paint surfaces appear whitish. It means absorptivity and hence also emissivity should be low – well below 1. I know how at least some of these absorptivity measurements are made (using an integrating sphere) and integrating spheres give the wrong answer for translucent materials – they suggest a reflectivity lower than it actually is (I know I design them). Consider how the interior of an igloo could be at +18C with minimal heating if the interior walls had an absorptivity of about 1. A high absorptivity would make an igloo more or less the equivalent of a sub zero cool store. Much more significantly, consider how the temperature in the antarctic as measured from satellites is around 180K when the coldest point even on the high plateau is more like 220K. The only way that I know for a low temperature to be recorded spectroscopically is if the surface emissivity is low.
Its an important issue because of the claim that snow gives rise to positive feedback. Supposedly the snow reflects incoming energy whilst radiating outgoing energy so it signifiucantly cools the surface yet the ground underneath would absorb incoming energy and thus would be more warming. If the emissivity of snow is far less than 1 then that theory is disproven.

“Now, I’m happy for folks to comment on this proof”
Seems to me to be sound.
The notion of emissivity for S-B as usually expressed is a surface emissivity. For a partly transparent medium like a gas, it’s a bit more complicated.

Stephen Singer

I’ll take a shot at this task though I’m a bit fuzzy still about it. I’ll give my current wimpy understanding.
1. Planet with mass and GHG free atmosphere.
2. Planets gravity pulls down on the gas compressing it causing heat near the surface.
3. Convection sets in and gas rises. cools then back to step 2.
It’s just to simple to be believable.

General P.Malaise

great article.
….my tomatoes still die when the temperature goes below freezing.

Mydogsgotnonose

Willis, if i may call you that, you have in my view made the same fundamental ,mistake as most ‘climate scientists’, and it comes from not understanding heat transfer.
First a correction to the IPCC thought experiment: if you remove the atmosphere you have no water precipitation so no clouds or ice, but you still have the seas [which by magic can’t evaporate!]. Emissivity falls from 0.3 to 0.07 so equilibrium radiative temperature falls to ~0°C meaning maximum GHG warming is 15 K.
However, if you the put back the atmosphere sans H2O and CO2, you still have aerosols and convection. Real present GHG warming is ~9 K.
The key is that you must always have lapse rate warming and it’s controlled by convection. The real radiative temperature with an atmosphere is always less by that convective temperature drop.

The only problem I see with your proof is the assumptions. A “GHG Free” atmosphere. On the one hand you say everything on the surface emits in the IR and give a long list of emissivities near one. On the other you say “except the air”…. It just causes me to think that you are defining the air as the functional equivalent of a vacuum… If it can absorb surface heat and convect, but NEVER emit, how can it ever then cool to return to the surface? Does not the assumption force another paradox? High altitude hot air that reaches equilibrium at the highest possible temperature that ever rises from any spot?
It just seems to me like it is a bit of a tautology with all the reality squeezed out of it…
Or, as one wag once said of ‘how an economist stranded on an island would use his strongest skills to open a food tin without a can opener: ‘First, assume the can is open…’..”

Anteros

Hi Willis,
I assume when you say the earth receives 240 W/m2, that’s a typo for 340?
If not, I’m going to have to go back to school 🙂

“And because the atmosphere is transparent, this means that the planet is radiating to space more energy than it receives. ”
I fail to see how this is a given with an IR transparent atmosphere. It would behave like a black body and radiate like one, except for one thing: the atmosphere would be heated by conduction and distribute heat by convection. As the nonGHG atmosphere cannot radiate IR, it would have to heat up and that’s the source of elevated temperature. Once heated, the atmosphere would go to equilibrium with the surface and would distribute heat back to the surface where IR would carry it away.
I would say that CO2 and water vapor are energy leaks, or rather small holes in the glass of the greenhouse, allowing heat to move both in and out during the day and out only at night.

I think I see the problem you have with conservation of energy, but let’s do a little story.
You have a black body that is emitting exactly as much as it absorbs, but when the Sun first hit it, this was not the case. There was a period when more heat was going in than out. Once it had warmed, then the surface went to equilibrium with the input and output.
The same would be true when the IR-clear atmosphere is added. There would be a time during which the surface/atmosphere would be getting up to temperature and then go to equilibrium as above. Thus, the planet is warmer than a gasless black body.
That’s my read—it just appears that you ignore conduction between the surface and the atmosphere.

alex

OMG.
Did not expect, Eschenbach has such grave problems with physics.
He writes
“the Stefan-Boltzmann constant is a tiny number, 0.0000000567 (5.67E-8).”
Sorry, the the Stefan-Boltzmann constant is a DIMENSIONAL constant.
You never can say a dimensional constant is “tiny”, because its numerical value depends on the units,
For example
σ = 5.6704)×10−8 W m−2 K−4 in SI
or
σ = 5.6704×10−5 erg s-1 cm−2 K−4 in CGS
or you can also write it
σ = 0.56704 erg s-1 m−2 K−4
and it looks already not that tiny!
.
.

Anything is possible

I’ve been reading a lot, but saying very little, ever since first becoming acquainted with Nikolov and Zeller’s theory.
FWIW, my “elevator speech” can be summed up thus :
On a planet with no atmosphere, radiation is king, no other processes occur and it can explain surface temperatures almost perfectly (witness the Moon).
Introduce an atmosphere, regardless of composition, and things start to get complicated, because you introduce the additional processes of convection and conduction.
Gravity is a key, (but unchanging) element because, along with the mass, it defines the vertical structure of any atmosphere, and hence the surface pressure.
The greater the surface pressure on a planet, the more influence conduction and convection have on surface temperatures, and the less influence radiation has (witness the unchanging temperatures on the surface of Venus).
Higher surface pressures elevate surface temperatures by suppressing convection because the greater the weight of the overlying atmosphere, the more energy (heat) is required to enable the process to get under way.
Nobody is ever going to disprove N + Z by obsessing about the details of all the complex processes that occur in the atmosphere, you have to look at the bigger picture.
If N+Z are correct (reserving judgement on that one) what they are is essentially saying is that the average surface temperature of any planetary body is pre-determined by insolation, surface pressure and albedo, and that all the processes that occur in any atmosphere – regardless of structure or composition will adjust, and act in such a way essentially by definition, as to preserve the average surface temperature of that body. Holy moley!!!
Ultimately, there will be only one way to settle this argument. There are literally billions of planetary bodies out there waiting to be discovered. One day (which maybe sooner than anyone anticipates) we will develop the technology to acquire the relevant data from a large enough number of those bodies that the theory will be proved, or disproved, once and for all. Until then, there’s going to be one heck of an argument. Try and Enjoy it! (:-

crosspatch

We aren’t talking about heat. We are talking about temperature. In a perfectly transparent atmosphere all of the heat being radiated would radiate out. But radiation would be the smallest of available heat transfer mechanisms. There would also be conduction because the atmosphere touches the planet. So the actual physical surface interface of the planet would be slightly cooler and the atmosphere will be slightly warmer. We would have a warmer temperature at 5 feet above the ground (but a cooler temperature AT the ground). The problem is all this talk about radiative heat loss at the surface. The main loss of heat from the surface of the planet isn’t radiation, it is and the loss from evaporation of surface water which absorbs a huge amount of heat when simply changing state from liquid to vapor without any change in temperature. [SNIP– way off topic. I’m talking about a GHG free atmosphere, as are Jelbring and N&K. Sorry, w.]

beaker

Just a small correction. Night vision uses a silicon detector and amplifies the available ambient light. Silicon is not responsive in the MW or LWIR, 3-5um and 8-12um, the naturally occuring atmospheric IR windows where us radiometric guys make our measurments. A FLIR or Forward Looking Infrared “see’s” thermal differentials without visible light. I believe you are referring to a FLIR, not night vision.

@Willis Eschenbach
Not being familiar with the N&Z or Jelbrick theorems, you do ignore the far reduced but still present conduction and subsequent convection present in the system. This would cause a drop in the energy available to be radiated due to loss to kinetic energy. I don’t know how much of an effect this would have on allowing increased warming above and beyond the S-B calculations because I don’t want to do the math right now but it is a place for energy to go since you added a liquid to the system.

How would Earth’s surface temperature change if atmospheric pressure were doubled, that is, increased to 2 atm by adding more N₂ (and nothing else)?

crosspatch

In other words, on a planet without an atmosphere surrounded by a sphere of tiny suns, the surface is some temperature and all photons of LWIR radiate from the surface. Add an atmosphere and the temperature of the SURFACE drops because that atmosphere conducts some of the heat away, the temperature of the atmosphere rises and where each photon radiates from is variable due to convection. Some will radiate from the surface, some will radiate from 1 foot above the surface, some will radiate from 1000 feet above the surface. Even if the air is completely transparent to IR it will still be warmed by conduction by contact with the surface of the planet, cool the surface, warm the atmosphere. The atmospheric temperature will still vary by the adiabatic lapse rate.
You seem to have been assuming a warming atmosphere without any associated cooling of the surface. Don’t confuse surface temperature with “surface temperature”. What we call surface temperature in most cases is the temperature of the atmosphere some distance above the surface. To my knowledge, nobody actually records the surface temperature of the planet itself except possibly the oceans. [NOT SO. Repeat after me, “GHG-free atmosphere”. The surface is the only thing that can radiate. w.]

Willis Eschenbach

Anteros says:
January 13, 2012 at 10:22 pm

Hi Willis,
I assume when you say the earth receives 240 W/m2, that’s a typo for 340?
If not, I’m going to have to go back to school 🙂

Apologies for the lack of clarity, Anteros, that’s the amount after albedo reflection of 30% of the incoming.
w.

Willis Eschenbach

alex says:
January 13, 2012 at 10:36 pm

OMG.
Did not expect, Eschenbach has such grave problems with physics.
He writes
“the Stefan-Boltzmann constant is a tiny number, 0.0000000567 (5.67E-8).”
Sorry, the the Stefan-Boltzmann constant is a DIMENSIONAL constant.
You never can say a dimensional constant is “tiny”, because its numerical value depends on the units, …

That’s it? That’s my crime? You are busting me because I called ten to the minus eighth tiny? You are a waste of bandwidth, sir. I specifically requested that people not bother me with this kind of petty nit-picking, and yet here you are.
Come back when you have something of substance to say, and my advice for your optics would be to leave off the “OMG”, it makes you sound like a Valley Girl.
w.

NoIdea

Having made only a superficial reading of N&Z, can someone explain the difference between that and Harry Huffman’s explanation? They seem largely the same although Huffman argues N&Z are not quite correct. As for Willis’ wish for a clear explanation, Huffmans several posts on his blog appear to do so quite well. For me as a layperson looking from the outside, Huffmans explanation makes sense but more usefully meets the test of Occam’s razor…

Willis Eschenbach

beaker says:
January 13, 2012 at 10:42 pm

Just a small correction. Night vision uses a silicon detector and amplifies the available ambient light. Silicon is not responsive in the MW or LWIR, 3-5um and 8-12um, the naturally occuring atmospheric IR windows where us radiometric guys make our measurments. A FLIR or Forward Looking Infrared “see’s” thermal differentials without visible light. I believe you are referring to a FLIR, not night vision.

Thanks, beaker, but that’s not true. There are two kinds of what are usually called night vision devices, image enhancement and thermal imaging. I’m speaking of the second of these. See here for details.
w.

Genghis

1. The non greenhouse gas atmosphere is a perfect conduction insulator to space, it can’t radiate its heat out.
2. The radiation transparent atmosphere is heated from the surface via conduction/convection until the atmospheric average temperature is at the S-B average. (Almost exactly the same way GHG’s heat the atmosphere, except that it is the planets surface molecules directly heating the atmosphere.)
3. According to the ideal gas law the average temperature will be at the midpoint of the atmosphere with the upper half lower than the S-B average temperature and the lower half higher than the S-B average temperature. I think with our earth the temp at 5k altitude is something like -18˚.
4. The thicker and denser the atmosphere, the higher the near surface atmospheric temperature will be.
5. Once the atmosphere is heated, the net radiation from the surface will be exactly the same as if there is no atmosphere, but the near surface atmosphere temperature will be warmer than the S-B average.
I can give a more detailed explanation tomorrow, but I just wanted to get this in tonight.

Willis Eschenbach

Michael Bergeron (@zerg539) says:
January 13, 2012 at 10:50 pm

@Willis Eschenbach
Not being familiar with the N&Z or Jelbrick theorems, you do ignore the far reduced but still present conduction and subsequent convection present in the system. This would cause a drop in the energy available to be radiated due to loss to kinetic energy. I don’t know how much of an effect this would have on allowing increased warming above and beyond the S-B calculations because I don’t want to do the math right now but it is a place for energy to go since you added a liquid to the system.

Michael, the energy radiated by the surface is fixed. It must emit what it recieves, no more and no less. Energy will go into and out of the transparent GHG-free atmosphere, but that is net zero, no loss or gain.
The main point is that for the surface to be warmer, it must radiate more … but then it’s violating conservation of energy. So speculations about possible mechanisms are futile, because the surface cannot be warmer than it it.
w.

Pops

One tiny nit, Willis.
That’s how night-vision goggles work, they let you see in the infrared.
Night vision goggles amplify visible and near-visible photons reflecting off objects and impinging on the device, such as are produced by starlight. You’re probably thinking of infrared sensors (e.g. FLIR) that rely on the emissivity of the observed scene in LWIR, MWIR, or SWIR bands – which “curiously” happen to align with gaps in CO2 and H2O absorption of infrared radiation.
In military applications, night-vision goggles are typically helmet-mounted devices used by everyone from infantry to pilots. IR sensors are usually larger devices with relatively massive optics and cooling systems, and are found mounted on airborne platforms and connected to MFDs in the cockpit.

crosspatch

I have used light amplification night vision devices that also had IR capability along with an IR search lamp built into the device for use in completely dark conditions (inside of something where there is no ambient light to amplify).

jorgekafkazar

It’s late, so I’ll just maunder. Hopefully, I’ll maunder minimally.
☻Wouldn’t a planet lit by thousands of suns eventually achieve solar temperature, say, 5000°?
☻The problem with Stephen Singer’s comment is that the compressed atmosphere would heat over its entire depth, not merely at the surface.
☻Meinhundthatkeinenase is looking at a more complicated model. Convection heating would occur, but the transparent atmosphere would not radiate the extra heat.
☻But is there really such a thing as a transparent atmosphere?
☻How were the absorption spectra of gases determined? Did they shine light down a tube 100 miles long? Or did they use a shorter tube? How long? Did they control the temperature of the tube foot by foot? Is that short a tube accurate enough for the levels of energy and accuracy we’re dealing with?
☻What about diurnal atmospheric thermal tides? Wouldn’t the daily increase and decrease in atmospheric thickness translate to work? Wouldn’t work heat the imaginary column of air? Wouldn’t it heat more at the bottom than at the top, creating a “lapse rate”?
☻Could it be that other factors will cancel out, leaving the apparent lapse rate as an artifact dependent only on atmospheric mass or density?
☻Night, all.

amazing willis how few people can follow instructions.
nick stokes is correct. Nice proof.
Sorry to see TB act that way. Tamino once banned Lucia for asking a question of the 2nd law.

wayne

“How would Earth’s surface temperature change if atmospheric pressure were doubled, that is, increased to 2 atm by adding more N2 (and nothing else)?”
Well, by Stephen Wilde, the increased pressure and density would bear down on the surface increasing the conduction of energy from the surface cooling it, which would therefore reduce the amount of radiation also cooling the surface. In other words the conduction / radiation ratio would shift in the conduction direction. More conduction, less radiation.
Since conduction is slow, the air at the surface would be warmer and that would also cause more convection to constantly bring more cooler upper air in contact with the surface. All in all, the lower air would be warmer, probably in the doubling case much warmer. But that is just way we get our environmental lapse rate right now in our atmosphere.
Also, if there is any absorption of radiation by the air, then more radiation would be absorbed lower due to the increased density and that can be from both solar radiation and surface infrared radiation. That too causes more warming lower.
There’s more. High density gases hold onto their internal energy better radiatively, there are more molecules in a given volume so the distance that radiation travels between absorptions decreases. This too keeps the temperature higher for it is harder for that energy to radiatively escape from a given volume of air.
Each one of those statements seems true, so it appears just that simple, more mass causes more warming of the low atmosphere and this likewise causes more warming of the air all of the way up to the top.

Peter Czerna

@willis
You are absolutely right that the N&Z speculations are junk. Almost every sentence in their contributions is either incomprehensible or plain nonsense.
Brave of you to give an ‘elevator speech’ version of GHG theory. Given the demands for concision, though, I think you go wrong or oversimplify on a number of points.
• The surface of the earth emits energy in the form of thermal longwave radiation.
– Get the nitpicking out of the way: ‘thermal’ is not necessary.
– The surface of the Earth also loses energy by conduction to the atmosphere and the subsequent convection.
The convected air, both before and after mixing, is at a lower temperature than the surface and so radiates less.
Unlike the 2D surface, the 3D lower atmosphere acts as a thermal accumulator during periods of low insolation (e.g. nightime). In electronic terms it would be the equivalent of a capacitor.
– I appreciate that I have gone beyond strict GHG ideas here, but you cannot discuss planetary temperatures just in terms of GHGs.
• Some of that energy is absorbed by greenhouse gases (GHGs) in the atmosphere.
– OK, of course.
• In turn, some of that absorbed energy is radiated by the atmosphere back to the surface.
– I get tetchy whenever I read about this ‘backwelling’ radiation.
In radiative terms, photons are emitted randomly in all directions: forwards, sideways and backwards. A proportion will head back towards the surface, most will not.
A GHG molecule that has absorbed radiation from the surface will also have its kinetic energy increased and pass on some energy by colisions with neighbouring atoms.
A proportion of any radiated energy will also be absorbed by other gas molcules.
What counts here is not the warming of the surface, but the warming of the atmosphere.
• As a result of absorbing that energy from the atmosphere, the surface is warmer than it would be in the absence of the GHGs.
– Again, the only temperature you are considering is that of the ‘surface’ and neglecting the heat stored in the atmosphere.
– At the moment, where I live, we have snow and ice on the ground but a pleasantly warm south wind and bright sun. I don’t care much about the surface temperature today.
Sorry – we’ve gone up three escalators by now and got to the roof.

crosspatch

[NOT SO. Repeat after me, “GHG-free atmosphere”. The surface is the only thing that can radiate. w.]

NOT SO! The atmosphere TOUCHES the surface. It will warm by conduction. That will COOL the surface and WARM the atmosphere. Radiation has nothing to do with that. The atmosphere will then convect … GHG or no GHG. Now the surface has cooled and the atmosphere has warmed. Add a little wind and the conductive loss increases at the surface and the atmosphere warms even more. The efficiency of heat transfer by conduction is much greater than efficiency by radiation. That warmed air (with NO greenhouse gas at all of any sort, make it pure nitrogen if you like) will then begin to convect. Some of it will radiate at the lower altitudes, some of it will radiate at higher altitudes. Earth will radiate all the heat that it receives but that heat will not be even because of the chaos of turbulence caused by that convection. Add hills, mountains, random trees, etc. and that turbulence can become quite chaotic and result in very uneven temperatures.
Model the atmosphere as a bunch of concentric surfaces that are transparent to IR but still radiate. The surface at 1 foot altitude has a given amount of radiation and a given amount of surface area. The surface at 1000 feet has a larger surface area so with a given amount of total heat content it’s “surface” is cooler. At 10000 feet, the “surface” is even cooler and at the very tipppy top of the atmosphere you have the greatest “surface area” of all but the temperature at any given point of it is lower.
Even an atmosphere with no GHG will still exchange heat by conduction and will still convect and will still radiate heat as it rises. It will still have an adiabatic lapse rate.

crosspatch

Take for example a radiator on a car (bad name, actually, because it doesn’t lose heat by radiation, it looses heat by conduction to the air, more air flow, more transfer of heat. Air flow doesn’t change radiation one iota. It is a heat exchanger to air). Rule of thumb is you lose 10% efficiency with every 1,000 feet of altitude because the air becomes less dense. At over 10,000 feet they basically become useless unless they are significantly over sized. About the only place on the planet that radiation would play a significant part in heat loss would be at the top of Mt. Everest.
Part of my life experience is designing flight qualified electronics that were required to be convection cooled to 10,000 feet altitude. That is hard to do because at 10,000 feet, heatsinks start relying on radiation as the major heat transport and radiation is the LEAST efficient heat transfer mechanism there is. The result was that heatsinks had to be much larger to work at 10,000 feet because conductive loss is so much less.
Earth’s surface acts as a conductive heat exchanger to the atmosphere. Radiation at the Earth’s surface is a minority route of heat transfer. Conductive losses are much greater.

Bill Hunter

“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.”
I am not sure this is correct. If the GHG-free atmosphere is cooling the thinnest surface layer (via conduction and convection) what it has absorbed it is not radiating. Like a water-cooled engine block if you remove the water its going to heat up to equilibrium to radiate as much energy as it absorbing from the combustion. But with the water cooling system the block is cooler.
OK so the heat goes into the GHG-free atmosphere and convects upwards. Its not going to radiate rapidly because a substance is as efficient at radiating as it is at absorbing radiation. And a GHG-free atmosphere is considered to absorb zero by AGW scientists. I think that is incorrect also. Argon has a emissivity about .0005, meaning its quite transparent but not completely transparent. CO2 has an emissivity around .08 meaning its about 160 times more efficient at radiating than the IR inert Argon. I presume this relationship holds with other monoatomic gases as well. Supposedly the diatomic gases have higher emissivities than the monoatomic gases and both have far less emissivity as triatomic gases like CO2 and water vapor.
But the problem is an inefficient emitting substance has to be hotter to emit the same level of radiation as a substance which is a theoretical black body. So this heat that is being absorbed into the GHG-free atmosphere is trapped there and the surface film is being cooled in the process and also not emitting its budget to the sky. . . .so the system heats until the budget is balanced again.
Keep in mind when thinking about surface temperatures that we don’t measure the actual surface temperature but instead the warmth of the air 6 feet above the surface so a little irrationality is possible here.
Gravity’s role is to run the convection engine that separates the heat from the surface and warms the entire atmosphere.
Now I am not sure thats how it works but it does seem logical.
And I think the interesting part is even if thats not how it works the idea of a GHG-free atmosphere is still an impossibility. The term GHG-free atmosphere is in essence an oxymoron as the only way to have a GHG-free area above a surface is to have nothing there.
Finally, it may be up to 160 times less efficient at absorbing GHG but when there is 2500 times more of it than CO2 it may belittle the effect of CO2 so this should still work even if the mechanism is back radiation.
So this is when somebody pops in with the radiation curve and the CO2 bight. Well maybe that bight is created in a thin area of the atmosphere where water vapor is missing.
With that I am going to put my shield over my head.

The basic issue is that there is no such thing as an equlibrium temperature, or equlibrium flux. The solar flux is zero at night and about 1000 W.m-2 around summer noon. The sun heats the ground during the day. 1000 W.m-2 corresponds to an equlibrium temperature of about 93 C. Dry ground may reach 50 or 60 C. At 50 C, the surface can only dissipate an excess of ~ 200 W.m-2 by IR emission. There rest is dissipated by convection. Some heat is stored below the surface by thermal conduction and gets radiated later in the day. The peak surface temperature is not reached until about 2 hours after the peak solar flux. This is the classic ‘signature’ of a therma storage oscillator. It means no thermal equilibrium.
The air is heated mainly by convection and the first 2 km or so above the surface acts as a ‘thermal blanket’ that cools quite slowly by radiation at night when the convection stops. Typical ‘average’ numbers are 50 W.m-2 lost from the surface and about 50 W.m-2 lost at the 2 km boundary. This is the ‘dynamic balance’ of the so called greenhouse effect. The heat capacity of a 2 km x 1 m^2 column of air is about 2 MJ.K-1. 12 hours of night time cooling at 100 W.m-2 is 4.3 MJ.m-2, so the night time ‘thermal blanket’ cooling is around 4 or 5 K. Usually, the air is moved on by the weather system before this cooling is observed.
As the air rises through the atmosphere it cools by expansion. Most of the IR cooling radiation to space originates from the water bands at around 5 km altitude. The ‘average’ lapse rate is about -6.5 K.km-1. To get to 5 km the air has to cool by 5 x 6.5 = 32.5 K. This is where most of the 250 W.m-2 ‘thermal equilbrium’ to space emission originates. The cooling occurs as the linewidths of the water band lines start to narrow and the water vapor concentration drops becasue of condensation. The IR flux ‘escapes’ beteen the water lines and does not get reabsorbed.
Almost all of LWIR flux reaching the surface comes from the first 2 km ‘blanket’. The air above 2 km up to the tropopause acts as a second independent thermal reservior that cools to space 24/7. It just keeps on cooling until it gets heated again by the next convective ‘pulse’ the following day. The daily temperature fluctuation of this upper reservoir is about 2 K or less. There is no equilibrium and the tropopause just moves up and down in altitude with latitude and seasons to maintain the thermal balance.
The Earth’s surface temperature can only be explained by the dynamic coupling of heat into thermal storage reservoirs. There are at least four thermal reservoirs and 6 energy transfer processes needed to explain even the basics of the surface temperature.
It is time to stop thinking in terms of an equlibrium flux.
(A freight elevator ride?)
This is a complicated subject. There are more details on my website at http://www.venturaphotonics.com. There is also a book ‘The Dynamic Greenhouse Effect and the Climate Averaging Paradox’ available on Amazon.

crosspatch

Take a rock in a still air in full sun and take its temperature.
Put a fan on that rock for 30 minutes and take its temperature again.
The rock will be cooler, the air will be warmer. No greenhouse gasses needed.

wayne

“which “curiously” happen to align with gaps in CO2 and H2O absorption of infrared radiation”
Glad you said that Pops, that is so curious isn’t it. So where is this -20 degC worth of LW radiation energy coming from when pointing a thermal radiation thermometer at the sky if the instrument is tuned to AVOID all GHG lines, right in the radiative “window” frequencies? That definitely perked my mind up. Hmm…
(I did earlier read of a report directly from the FLIR manufacturer on that very subject)

Girma

Verifying Willis’ numbers

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.

Radiation = Emissivity times SBconstant times Temperature^4
240 = 1 x 5.67 x 10^(-8) x Temperature^4
Temperature^4 = (240 x 10^8)/5.67 = 42.32804233 x 10^8
Temperture = (42.32804233 x 10^8)^0.25 = 42.32804233^0.25 x 10^2 = 2.55 x 100 = 255 K
Deg C = K – 273 = 255 – 273 = – 18

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.

Difference between actual and theoretical global mean temperature = 18 + 14 = 32 deg C
Willis, it is all right!

Lew Skannen

If the atmosphere is GHG free I cannot see how the temperature at the surface can change.
If there are GHGs present I believe that the Stefan-Boltzman equilibrium surface of the planet is raised above the surface and is therefore a larger sphere. This can then allow for radiative equilibrium with a higher surface temperature without violation conservation of energy.

@Willis
Again you are narrowing yourself into only considering a single form of heat transfer, Incoming radiation heats the blackbody, this in turn through conduction loses some of that heat through conduction to the atmosphere, all of the energy transfered by conduction cannot radiate as IR. You are now ignoring an entire realm of thermo dynamics, yes any radiative energy absorbed by the blackbody has to go somewhere once it is in S-B equilibrium but it is not restricted to a single energy form, heat is both EM radiation and kinetic energy.
Adding the atmosphere would add a second source of radiation once it has also reached an equilibrium point because even if the atmosphere is IR transparent it will still radiate IR of which a bit less than half will radiate back into the planet. This in turn will begin to raise the energy going into the planet by radiance, which will then raise its temperature under the S-B. The only way the atmosphere does not conduct heat energy away from the planet is if there is no way for them to physically interact, though the only way I see gravity having anything to do with this is as a driver of convection which just speeds the rate of conduction into the atmosphere.
Energy from the sun must equal the energy leaving the blackbody in ALL FORMS not just radiation.

Paul Martin

Willis: consider the difference between ground frost (radiative cooling) and air frost (radiative cooling + convection).

Willis Eschenbach

Thanks, Genghis, I would say that yours is the first substantive response. It is not (as far as I know) the N&Z or the Jelbring hypothesis, but it is interesting. Comments below.
Genghis says:
January 13, 2012 at 11:14 pm

1. The non greenhouse gas atmosphere is a perfect conduction insulator to space, it can’t radiate its heat out.

True

2. The radiation transparent atmosphere is heated from the surface via conduction/convection until the atmospheric average temperature is at the S-B average. (Almost exactly the same way GHG’s heat the atmosphere, except that it is the planets surface molecules directly heating the atmosphere.)

I don’t think so. As soon as the dry adiabatic lapse rate temperature profile is established, circulation will stop and the atmospheric temperature will stabilize. At that point the energy in the atmosphere will be evenly distributed from bottom to top. However, because the molecules at the top of the atmosphere have more potential energy, they have less kinetic energy, which means a lower temperature.

3. According to the ideal gas law the average temperature will be at the midpoint of the atmosphere with the upper half lower than the S-B average temperature and the lower half higher than the S-B average temperature. I think with our earth the temp at 5k altitude is something like -18˚.

I don’t see how this is physically possible. If the lowest part of the atmosphere is constantly warmer than the planetary surface immediately below, the heat will constantly be flowing from the warmer atmosphere above to the cooler surface below. How is that possible?
In addition, I see nothing in the ideal gas law requiring the atmosphere mid-point to have the same temperature as the surface. You’d have to explain that one.

4. The thicker and denser the atmosphere, the higher the near surface atmospheric temperature will be.

I don’t think so. The dry adiabatic lapse rate is g / Cp, where g is gravity and Cp is the specific heat of the atmosphere. The lapse rate does not vary with elevation, which means that Cp doesn’t vary with density, so I don’t see how a denser atmosphere would perforce be warmer.

5. Once the atmosphere is heated, the net radiation from the surface will be exactly the same as if there is no atmosphere, but the near surface atmosphere temperature will be warmer than the S-B average.

If so, there would be a constant flow of heat from the warmer atmosphere to the surface. Not physically possible.
Thanks, much appreciated,
w.

David

I have a problem with your proof by contradiction. Let me quote it here so that it is fresh in the mind:
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.

Let me propose a thought experiment. We have a black box floating in space evenly surrounded by a sphere of mini-suns, as at the start of your proof by contradiction. The black box radiates exactly the same energy as it receives and is in temperature equilibrium. The temperature of the black box is given by the S-B law.
We don’t know what is inside the black box. At its simplest, it could be a single solid mass. Or perhaps there could be two solid masses inside the black box, one at temperature T1 and one at temperature T2. Each mass radiates towards each other as well as the universe generally. Each mass within the black box is continuously exchanging energy with the other, and their temperatures vary over time as well. We don’t care because overall the black box as a whole is radiating as much energy as it receives. We can use the S-B law to calculate an equivalent black body temperature, but this is an exercise in maths: the temperature we derive from such a calculation is relevant only to the black box as a whole. It is not an “average temperature” of the two bodies within the black box; in fact we cannot deduce any information about the masses within the black box using only the S-B law. We can only use the S-B law to describe the black box itself, and everything it contains.
Of course the black box could contain many, many masses. Some could be solid (earth) some liquid (oceans) and some gaseous (atmosphere). Each mass could vary in temperature in complex ways, continually transferring energy between each other. But overall the entire system can be described by the S-B law, and the entire system overall is in equilibrium with the universe.
Getting back to your proof by contradiction. When you add the atmosphere you now have two masses inside the black box. You then assume (this is the assumption that you are going to come back to and say is false, once the proof by contradiction is completed) that the atmosphere heats the ground. You then say that because the ground is hotter, it must radiate more energy (by S-B law) which is false therefore the assumption is false.
But this is not correct. You have not taken into account any change in temperature of the atmosphere.
Take your black box which is radiating according to S-B law. Put inside the black box some solid mass (ground). Take your measurements and deduce the black body equivalent temperature. Now add a second mass to the black box, without introducing any extra energy into the system. This second mass is a gas (atmosphere). Now assume that the presence of the atmosphere increases the temperature of the ground. The two masses exchange energy inside the black box, the ground heating and the atmosphere cooling until they reach equilibrium with each other. The entire system (the black box) will still be in equilibrium with the universe if one of the masses inside (the atmosphere) is at a different temperature compared to the temperature of the other mass inside (the ground).
Your proof by contradiction is flawed. You cannot deduce the temperature of any item within the black box according to the S-B law. You can only look at the system as a whole. You said: …I’m interested in people who can either show that my proof is wrong… and I believe I have done so.
I cannot say anything about the Jelbring or the N&Z hypothesis. As I understand it, the presence of an atmosphere in gravity will lead to a higher pressure and higher temperature at the surface. This can only come about because the temperature reduces at altitude – conservation of energy as well as various Gas Laws apply. This is exactly how our own atmosphere behaves. Whether or not this entirely explains the temperature rise of the Earth over the black body temperature, I cannot say. I am not trying to prove their theorem; I am only pointing out the mistake in your own criticism of that theorem.
I trust that you shall receive this in good faith. I am not impugning your character nor taking personal attacks; I just don’t see how your proof by contradiction is correct. Perhaps there is something I’ve missed; please correct me if so. Kindest regards,
David

Willis Eschenbach

Nick Stokes says:
January 13, 2012 at 9:57 pm

“Now, I’m happy for folks to comment on this proof”

Seems to me to be sound.

Thanks, Nick, that is significant to me.
steven mosher says:
January 13, 2012 at 11:33 pm

amazing willis how few people can follow instructions.
nick stokes is correct. Nice proof.

Thanks, mosh, your vote is significant as well.

Sorry to see TB act that way. Tamino once banned Lucia for asking a question of the 2nd law.

What’s the deal, does thermodynamics make people crazy? I love thermo because it cuts through all the other stuff to say that some things are simply not possible. Although upon reflection I do see how that could lead to panic if you’ve built your theories on sand …
My appreciation to you both for your comments,
w.

Julian Braggins

By introducing an unnecessary condition in your thought experiment, i.e. the multiple suns, you have made it impossible to gain any insight to the real working of the atmosphere.
Without that condition, the air would heat up to the surface temperature.
Differential heating , night / day, polar / equatorial, would induce circulation.
Lapse rate heating, determined by the depth of the atmosphere would ensue.
A new higher temperature equilibrium would be established.
But what would I know, I left school at 15, 64 years ago 😉

Willis Eschenbach

NoIdea says:
January 13, 2012 at 11:09 pm

Having made only a superficial reading of N&Z, can someone explain the difference between that and Harry Huffman’s explanation? They seem largely the same although Huffman argues N&Z are not quite correct. As for Willis’ wish for a clear explanation, Huffmans several posts on his blog appear to do so quite well. For me as a layperson looking from the outside, Huffmans explanation makes sense but more usefully meets the test of Occam’s razor…

So are you saying that you understand Huffman’s explanation? Because I couldn’t. Give us the elevator speech about that one if you understand it, it does sound similar from what I’ve read.
Or if you can’t give the elevator speech, consider that you might not understand Huffman after all.
w.

wayne

Willis: “Michael, the energy radiated by the surface is fixed. It must emit what it recieves, no more and no less. ”
Absolutely false. Conduction carrying away energy from that same surface does reduce the radiation leaving from that surface when in equilibrium. Willis, you can call it a reduction in the emissivity of that surface if your mind prefers. Well… that is really what does happens, the emissivity decreases. A surface receiving all of its energy by radiation and part of that energy leaving by conduction, then, the amount leaving by radiation WILL decrease under the amount received. WILLIS…. do you happen to remember the first law of thermodynamics???

Jerker Andersson

“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.”
Unless your point is to exclude conduction and convection in this thought experiment the GHG free atmosphere will also remove heat from the surface by conduction and convection. Each molecule in the atmosphere can emit radiation both upward to space and downward to the surface just as a GHG does. But it would not be able to absorb any outgoing radiation from the surface or reabsorb any IR emitted from the atmosphere toward space, only a GHG could do that. For the part that goes downward it will retransfer energy to the surface again.
In this case the more air molecules you add the more IR can be transfered via the atmosphere back to space until you get a balance where the energy transfer via conduction between surface and atmosphere is the same as the IR radiated from the atmosphere back out to space.
The atmosphere in this case works as a heat sink for the surface.
But since in this case both surface and the atmosphere would emit IR to the space then the temperature of the surface must be lower in order to split some of the radiation back to space between the atmosphere and the surface. As you said, the energy must be conserved.
To sum it up for a GHG free 100% transparent atmosphere.
– The surface gets heated by the incomming radiation.
– Some energy gets transfered from the surface to the atmosphere through conduction.
– Backward radiation out to space is now split up between atmosphere and surface thus the surface has to be cooler since it is emitting less.

Willis
Nice article.
I enjoy the input from both R Gates and Joel Shore over here and think Blogs such as this one would be diminished if everyone were to sing from the same song sheet. Both are knowlegable and argue their corner well-although I disagree with most of what they say and they do have a blind spot on Climate History.
Banning Joel from Talk Shop for the reasons stated seems extreme and makes me uncomfortable as it has echoes of Real Climate.
Come on Roger, you’ve always seemed a resaonable person. How about showing that you accept all scientific viewpoints even if you disagree with them? Banning should only be applied to especially irksome or abusive trolls and neither Joel or R Gates fit into that category by any stretch of the imagination.
tonyb

Willis Eschenbach

crosspatch says:
January 13, 2012 at 11:40 pm

… Even an atmosphere with no GHG will still exchange heat by conduction and will still convect and will still radiate heat as it rises. …

I will repeat it again. If there are no GHGs in the atmosphere, the atmosphere will not and cannot radiate energy. That’s the whole point. The only thing that can radiate is the surface. You keep claiming the atmosphere will radiate. It will not.
w.

David McKeever

The reason your thought experiment could radiate more heat than it gets (from the sun) is that you are adding thermal energy int he form of moving molecules. Boyle’s gas laws tell us if you pressurize a gas it will increase heat. So assuming that when you say you add an atmosphere you are adding low density gas molecules and allowing gravity to be your pressurizer then you would have a one time spike of temp. until it convects into the land/ocean/air and radiates out. Then it would return to the temp before you added the atmosphere. If the atmosphere was already compressed to 1 atm. at the sea level and lower pressures at higher altitudes before you added it, then it wouldn’t have any effect. (I think.)

Roger Clague

crosspatch 13 Jan 10.40pm.
This comment was snipped by the Willis, the guest poster.
crosspatch is debating and disagreeing with the post. He is not off topic. He has been censored. Please restore this comment.
Moderators should moderate not the poster.
The theory of gravitational enhancement claims there cannot be a Greenhouse gas free atmosphere. The mass of all gases in the atmosphere cause the so-called Greenhouse Effect.

crosspatch

“1. The non greenhouse gas atmosphere is a perfect conduction insulator to space, it can’t radiate its heat out.”
What? Everything with a temperature radiates. I don’t care WHAT a substance is, it will cool. It will cool until it reaches equilibrium with its background. Greenhouse has absolutely nothing to do with radiation, it has to do with absorption. Something can be completely transparent to LWIR and still cool down by radiation. A greenhouse gas is something that absorbs LWIR. It has nothing to do with what it radiates. So I can have a non greenhouse gas that heats via direct contact … conduction. It will STILL radiate that heat away. It just didn’t heat by absorbing LWIR.
Are you guys sure you know what greenhouse is?