A Matter of Some Gravity

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.

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.

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 🙂

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! (:-

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.

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)?

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…

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.

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.

“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.

[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.

“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.

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.

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!

@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.

“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.

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.

Willis, surely your transparent atmosphere is, like the standard GHE model, an unphysical and unhelpful concept, since in reality all gases will have some absorptive / emissive characteristics. If that were not so then, by definition, adding as much of this ‘atmosphere’ as you like cannot have any influence on the purely radiative balance between your planet’s surface and its shell of mini-suns, as you say. As soon as you concede that the added atmosphere can absorb and emit on its own account, though, you have an ‘atmosphere effect’, temperature gradients in that atmosphere, convection and so on, whereupon yes, the planet’s surface will warm as the effective radiating level moves upwards and away from the planet’s surface.
It seems to me that the basic error (in the Earth case, at anyrate) is in the assumption that the planetary surface receives a quarter of the available power coming in from the sun, continually. It doesn’t. I’m much more impressed by Postma’s thermodynamic analysis (‘Understanding the Atmosphere Effect’, ‘The Model Atmosphere’ etc.) in which he shows that consideration of a dynamic system, with a rotating planet orbiting a single sun, renders the introduction of a ‘greenhouse effect’ unnecessary, the (considerably) higher equilibrium temperature at the subsolar point plus the insulation of the atmosphere giving quite enough increase in average energy input and surface temperature to account for what we observe.
If I’m making a cup of tea, I need one cup of boiling water. Two cups of lukewarm water – even if the amount of heat energy is identical – just don’t do the work! It’s not only how much energy there is in the system, it’s also how it’s distributed.
As ever, a thought-provoking post. And now I know to keep an eye open for a copy of that Geiger book.

“If there are no GHGs in the atmosphere, the atmosphere will not and cannot radiate energy.”
As far as I know all atoms above 0K raidate IR, even molecules in our atmosphere. Otherwise the air can be heated to any temperature and it will never cool until it gets into physical contact with cooler molecules i.e heat transfer via conduction.

Why everybody here imitates Mr. Eschenbach, using hyphen in “Stefan-Boltzmann temperature”, “Stefan-Boltzmann equation”, and “Stefan-Boltzmann constant” expressions, as if “Stefan” and “Boltzmann” were two people who developed this formula?
Stefan Boltzmann was one man, his last name was Boltzmann, his first man was Stefan, and the correct way to use his name is “Boltzmann’s equation” or “Stefan Boltzmann’s equation” (if you insist for some reason on repeating his first name all the time) but not “Stefan-Boltzmann equation.” The “S-B” abbreviation, in this context, is incorrect.
Boltzmann killed himself, because the “consensus” among most of the respected, published and peer-reviewed “scientists” of his time was that Boltzmann was nuts. Since then, however, his classic formula has become a mandatory part of any high-school course of physics, and it is not clear to me, why discussing it here is of any interest, and why one has to be “mathematically inclined” to read one of the simplest formulas ever.
P.S. By the way, all gases and gas mixtures radiate heat, not only those containing the ubiquitous “green-house gases.” An atmosphere containing no water vapor or other “GHG” gases would warm up under sunlight and radiate heat, because light dissipates, to some extent, in an atmosphere consisting of any gas, however transparent.

“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, according to the GHG hypothesis, that would reduce the mixing ratio of atmospheric CO2 and less heat would be trapped. The surface would cool.
In reality 2 atm would change a lot of things, evaporation, convection, density of the atmosphere…

1) Earth/Atmosphere is a thermal machine (details unimportant)
2) Mechanical Energies are Earth rotational energy + Earth/Moon Potential Energy (Tides)+…….+Atmospheric energies (small)
3) Energy imbalance goes into tiny change of earth rotation speed or ……

Hello again Willis
We didn’t quite finish our discussion at the Moon/Mistress thread so I’d like to continue it here if you’re willing.
The key concept to keep in mind is that warming by conduction (between a solid surface and a gas) is always more efficient than cooling by conduction.
This is because a warming parcel of air rises and expands, is replaced by a cooler parcel of air which is also warmed by the surface and the cycles goes on so long as the surface is warmed by insolation.

First floor, giftware

Cooling by conduction is not quite the exact opposite of warming by conduction due to the phenomenon of temperature inversion.
When a warm parcel of air conducts with a cooler surface, the air cools, the surface radiates away the newly attained warmth. However, the parcel of air higher up cannot make its way down because it is blocked by the now cooler parcel of air underneath.
Though conduction WITHIN the molecules of air will move some warmth to the adjacent lower and cooler molecules, this process is very slow and inefficient, otherwise temperature inversions wouldn’t happen.

Second floor, ladies wear

Temperature inversions on Earth are most common near coastal upwelling zones (note the famous Californian smogs of the 70’s and 80’s) where cold upwelling water cools the air immediately above which prevents the air higher up from descending because it is now warmer than the air below.
They are also very common at the poles especially in winter where warmer air from lower lattitudes conducts with the frigid surface forming a barrier which stops the warmer air above from descending.

third floor, menswear

Therefore, with the above in mind, a previously bare rock planet, injected with a non-GHG atmosphere will first and foremost have its outgoing longwave reduced because of conduction.
Due to the fact that the equator of a sphere is the warmest, this is where the most conduction will occur. The atmosphere will transport this equatorial heat towards the higher lattitudes.
This conduction cannot cease until the atmosphere attains the same temperature as the surface at the equator.
In all this time, the outgoing longwave from the surface will be lower than that of a blackbody, i.e. the system as a whole (surface plus atmosphere) is accumulating heat.

fourth floor, manchester

The process will come to equilibrium when the atmosphere (at all lattitudes) reaches the same temperature as the surface AT THE EQUATOR (or near enough so that convection is a tiny trickle)
Therefore, the AVERAGE temperature of the ATMOSPHERE will be higher than the AVERAGE temperature of the SURFACE, i.e. higher than the SB temperature.
Theoretically, because of the limited conduction from a warm atmosphere to the cold polar surface will warm the surface by a small amount (temperature inversion prevents continual heat transfer by conduction) the polar surface will be warmer than it was when without an atmosphere.
By the same token, the equator will be cooler than they were when without an atmosphere.
Put simply, a planet with a non-GHG atmosphere would be dominated by temperature inversions.

fifth floor, home made pies

This is where I humbly get off
p.s. my last response at the Moon/Mistress thread is at http://wattsupwiththat.com/2012/01/08/the-moon-is-a-cold-mistress/#comment-860181
my best regards as always.
We need more Willisses in Science. He makes us think

I have talked with one engineer who is working infrared warmer manufacturer company. They have tried to warm air with infrared warmer and they have never managed to do so. They have even set tens of radiators to work at same time (hundreds kilowatts), no measurable results in air temperature. So the claims that infrared radiation warms atmosphere can’t be correct, so the main question is, what is absorption when you deal with gases (or air). How gases can backradiate anything if you can’t increase it’s temperature with radiation? If you have dust, water or other tiny particles in air, then radiation can warm these a little bit. They don’t add energy only transfers the original energy, so these can’t warm (add energy that increases temperature) anything cause they are not energy sources.

No gas is transparent to all radiation – even if it is transparent to infrared, it will absorb ultraviolet, x-rays, something, and be heated by them..
So the true receiving area, even for a planet with a perfect GHG free atmosphere, is the disk section of surface + atmosphere.
And I put it to you that the resulting lapse rate could raise the surface temperature at least a little above the SB theoretical limit.

Willis Eschenbach says:
January 14, 2012 at 12:37 am
“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.”
I dont understand this . Are you saying I cannot heat Nitrogen?
If I put Nitrogen in a bottle. I lower the bottle in water that is constantly at 293 K. I leave it there for 50 years. Now the Nitrogen should be at 293K too.
I build a rocket with an insulation chamber.. I put the Nitrogen bottle inside this chamber. I launch the rocket into space. Via radiocontrol I manage to open the insulation chamber and release the nitrogen bottle into empty space.
The nitrogen bottle is now at 293K ? Empty space is…2-3K? Wouldnt the Nitrogen bottle ratiate energy?

Okay I obviously know very little compared to you lot, but surely planet Earth has to radiate more than it receives to maintain a crust… ?

Willis I cannot believe that you do not understand adiabatic heat gains due to compression. [SNIP- I specifically asked you to stick to elevator speeches and disproving my proof. -w.]

I have only one question, why all the argument over a hyperthetic planet with an unreal atmosphere using equations that only apply to something that does not exist.
We have a real planet and a real atmosphere and a sun, the vagarities of which are real, there is a mystery to solve and the answers do not lay in hyperthetics.

[SNIP: read the instructions. Elevator speeches and disproofs only. -w.]

[snip . . off topic . . kbmod]

The air above the south pole in winter has as little CO2 and H2O as you’ll get anywhere, so makes the nearest thing to a GHG-free atmosphere we have.
If calibrated beacons at various wavelengths were put there the Dr. Spencer’s satellites could get a direct reading of absorption from a GHG-free atmosphere??

[SNIP: read the instructions. Elevator speeches and disproofs only. -w.]

“Willis Eschenbach says:
January 14, 2012 at 12:19 am
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. ”
Perhaps, but on earth we have a night and and day. Whereas night may in some degree may stablize. Day time with sunlight will heat the ground and air will rise- destabilizing the adiabatic lapse rate.

Willis, you have just done something no man has done before. In all the years of lurking on climate sites this is the first time I’ve seen peoples objections to the radiation balance model reduced to pretty much a single theme. Normally we all but drown in the extravagence of response.
My challenge to you is to now is to get just the right words to convey the fact that, if a gas doesn’t significantly absorb in a given wavelength range, then it follows that it doesn’t significantly emit in the same range. A challenge for the elevator speech maestro.

[SNIP: read the instructions. Elevator speeches and disproofs only. -w.]

[SNIP: read the instructions. Elevator speeches and disproofs only. -w.]

@John Marshall and all the other adiabatic compressors
Adiabatic compression cannot warm an atmosphere in any lasting way.
When a gas is compressed adiabatically its temperature is raised as long as no heat escapes from the gas.
In the real world, near-adiabatic compression usually only happens when a gas is compressed very quickly, as, for example, in a bike pump.
If you hold the gas compressed, heat will gradually escape by conduction/convection/radiation and the temperature will fall until it reaches ambient temperature again. A compressed atmosphere will just leak heat to its surroundings and return to ambient temperature.
A gas is not hotter just because it is denser. If it were, liquified gases would not be possible.
How can gravity apply continuous work compressing the atmosphere?
When does it decompress? (If a gas decompresses it loses heat (because of the work it is doing in expanding) and its temperature falls).
In other words a one-off compression will not permanently raise the temperature of an atmosphere.

[SNIP: read the instructions. Elevator speeches and disproofs only. Stick to the topic. -w.]

[SNIP: read the instructions. Elevator speeches and disproofs only. -w.]

[SNIP: read the instructions. Elevator speeches and disproofs only. -w.]

[SNIP: read the instructions. Elevator speeches and disproofs only. And mice. Mice are cute. -w.]

What is the physics explanation for why temperatures of a gas/star/planet increase as it is gravitationally compressed?
Why does matter do this?
I think the answer to this question will point to the answer about an atmosphere in gravitational equilibrium.
Otherwise, in a non-GHG atmosphere, the molecules next to the surface will be colliding with the surface 8 billion times per second.
Energy will be transferred from the surface to the non-GHG molecules in translational energy. These molecules then appararently NEVER lose their energy without colliding with another non-GHG molecule or the surface again. I don’t see how the atmosphere does not continually increase in temperature then. At some point, millions of years worth of solar energy will be locked up in the inert atmosphere.
[COMMENT: This is total nonsense. I mean, there is not a valid scientific thought in it. I leave it in to give a flavor of the nonsense that I am snipping. Give me your elevator speech, disprove my proof, or stay schtumm. What in that is not clear? -w.]

[SNIP: read the instructions. Elevator speeches and disproofs only. -w.]

[snip – you seem to forget the comment where you told Willis and I to go F*** ourselves about a month ago. As a result of that, and continued threadjacking and references to your website to try to draw traffic, you’ve been banned, do the words get out and stay out have any meaning to you? Apparently not. – Anthony]

Willis, my best shot at an elevator speech version of Huffman’s analysis. I am not saying that I believe him to be right, or that I even properly understand his claims, I merely observe that to me, a layperson, it makes sense and is simple. My original question was to seek a comparison between N&Z and Huffman’s ideas.
—————————————————————————————————-
All energy in the system is received from the sun.
The ‘US Standard Atmosphere’ defines the pressure/temperature gradient for the Earth atmosphere. For example, at sea level, the pressure is determined to be 1013 millibars and temperature 15C, while at 20000 metres the pressure is determined to be 55.29 Mb and the temperature -56.5C.
The atmosphere is largely warmed by direct solar infrared irradiation (the surface can and does warm a part of the atmosphere – but only transiently and locally).
‘Visible’ light passes through the atmosphere without warming it but is also reflected back by clouds, ice etc. The portion of the solar irradiance which warms the Earth atmosphere is the same portion as heats the Venusian atmosphere – the differing albedos play no part in that absorption.
The Venusian atmosphere at the same pressure levels as defined in the US Standard Atmosphere has a temperature that is 1.176 times that of earth (for example, at 1000Mb Earth has a temp of 288K and Venus 1.176 times that or 338K, while at 600Mb the figures are 260.8K and 302.1K respectively).
The 1.176:1.00 ratio is derived from the difference in distance from the sun – Venus receives 1.91 times the power from the sun when compared to Earth due to being closer, and applying SB to obtain the 4th root of the power gives 1.176.
Atmospheric pressure does not cause heating rather it enables the atmosphere to retain more heat energy per volume at higher pressures. ‘Greenhouse gasses’ via radiation facilitate increasingly rapid distribution of heat throughout the atmosphere rather than heating it per se (ie local temperature variations are more quickly dissipated by heat transfer, both vertically and around the planet).
The greenhouse effect does not warm the atmosphere, the sun does directly.

Stefan-Bolzmann radiation is called black body radiation because it applies to bodies. S-B radiation may apply to the atmosphere, but at orders of magnitude less than the surface. Willis is right to ignore any atmospheric S-B effect.
“Greenhouse” gases – CO2, H2O, NH4, etc, are such because their asymmetric modes of molecular vibration interact with long-wave radiation, at quantised energy levels. O2, N2 don’t have asymmetric modes of vibration. They can’t absorb long wave radiation ON ANYTHING LIKE THE SAME ORDER OF MAGNITUDE, and can therefore be ignored as “greenhouse” gases. It’s basic physical chemistry.
[Thanks, Phil. Fighting this level of ignorance is like wading through molasses. I appreciate the assistance. -w.]

wayne says:
January 14, 2012 at 6:30 am
Bill Illis says:
January 14, 2012 at 5:10 am
[SNIP: PLease stick to either an elevator speech, or a formal showing that my proof above is incorrect. Thanks, -w.]

The mechanics of W. Eschenbach’s thinking is interesting to observe. Temperature is a property of matter. Willis can’t grasp how gravity, which directly controls the gradient density of an atmosphere which is constantly stirred, agitated and wafted, can influence our surface temperature. Wow. Does gravity influence density? Is heating more efficient when you stir a dense or thin fluid?
[Again, I’ll leave this in, to give a flavor of the vague nonsense folks are posting. Please read the instructions, stick to an elevator speech for Nikolov or Jelbring, or a falsification of my proof. Thanks, -w.]

This is my “elevator speech” version of the discussion so far.
Postulate. Gibberish-gibberish-gibberish.
You’re right. Gibberish-gibberish-gibberish.
You’re wrong. Gibberish-gibberish-gibberish.
You’re all wrong and the original postulate is beeswax. This is why. Gibberish-gibberish-gibberish.
What’s a liberal arts education to make of all this? Could someone please tell me if humans are causing the planet to burn up, or what?

[SNIP: Read the instructions, stick to an elevator speech for Nikolov or Jelbring, or a falsification of my proof. Thanks, -w.]

Willis, can you also confirm that your model has an atmosphere thst can not radiate any energy at all? It seems there are a lot of posters that question that assumption, if so.
I thought anything raisef in energy tends to radiate it away eventually.

Essentially, more mass equals more gravity which results in a hotheaded person, radiating fury at a crazier rate the denser he be. :p

In an atmosphere basically IR-inert, there would still be an adiabatic lapse rate due to pressure differential with altitude.
Gas heated by conduction from the surface would expand and rise (convection), trading thermal kinetic energy for potential (gravitational) energy.
This thermal energy convected away from the surface as potential energy is no longer available for reradiation, and the potential energy acquired will be expended when the now-cooled body of gas eventually descends to equalize the pressure differential caused by the rising of another warmed body of gas.
This is why the “evenly-heated average” image has to be discarded for a more realistic picture of constantly-changing areas of maximal warmth (i.e. planetary rotation; noon is always moving).
So whether weather is climate or not, weather clearly regulates climate, and both received solar energy and gravity contribute to both weather and climate. The question (here again) is the relative magnitude of the “greenhouse” contribution, not whether it exists or not.

My elevator speech to fellow engineers is this: GH gasses are qualitatively like applying insulation on a hot pipe — it impedes heat-loss to the environment (outer space in earth’s case). Once applied, the pipe’s insulation surface (tropopause) is cooler than the bare pipe is (earth’s surface). So it’s losing less heat when insulated & the heated pipe surface (earth’s surface) is warmer than w/o the “insulation”.
That’s where the proposed 33K GHG rise (insulation effect) comes from — 288K (earth surface) – 255K (tropopause surface). Not a bad approximation, but valid IMO for an atmosphere w/only non-condensible GH gasses.

I recently watched a Horizon program on the BBC that mentioned the ‘South Atlantic Anomaly’. A strange depression in the earths magnetic field that affected the Hubble Space telescope. If this is the case then according to the Svensmark hypothesis then surely there should be an increase in cloudiness in this area. Does anybody now whether this is the case ? An interesting little study for some enterprising research student.

Hunter raised questions regarding snow as a blackbody. Between temperatures of
250 and 273 K, reasonable for snow, the emissivity is about 0.98. You’ll notice that snow around trees- picking up the infrared radiation from the tree, melts a lot faster than snow further from the trees.

Willis, you responded to one post as valid. Your response did not mae sense to me. here is the assertion you rejected…
4. The thicker and denser the atmosphere, the higher the near surface atmospheric temperature will be.
Willis responded…
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.
—————————————
I am not certain Willis’s response makes sense to me. The lapse rate may be constant, but it is a constant VARIATION,which appears to be predicated on g and Cp. (IE, the greater the gravity, the higher the specific heat of the atmosphere) What does “specific heat emanate from? If specific heat, which is the heat capacity per unit mass of a material, then the more materials there are per volume, then the greater heat per volume. Therefore an atmosphere of more (denser) material, will have a higher specific heat content then a thinner atmosphere. The lapse rate will be the same in both atmosphers, just the starting point or temperature will be different.
What am I missing here?

Willis
interesting post as always.
There seems to be some confusion about the roles of conduction and convection in the GHG free atmosphere. I think the point is that when the GHG free atmosphere is ‘added’ it will take some time for the system to reach equilbrium. During this period the atmosphere will be heated by conduction and I think it therefore follows that during this period the outgoing radiation will be LESS than the incoming radiation simply because some of that energy is being used to heat the atmosphere by conduction. Once the system reaches equilibrium I think you are quite correct -incoming radiation will equal outgoing radiation. The outgoing radiation from the surface will pass through the atmosphere as if it was not there.
Roy Spencer says that in this model convection has no role to play. I would not argue with Roy. But even if there was convection all it would do is assist in raising the atmosphere to equilibrium temperature.

Willis, excellent elevator pitch!
I agree completely, as the gas, which can’t radiate or absorb, will gain energy from contact with the surface, causing the surface temperature to drop. Since the gas can’t radiate the energy away, and the surface temperature has dropped, the next contact of a gas molecule with the surface will exchange energy in the other direction. Initially, the temperature will drop, but in the steady state, the temperature of the surface will remain at the non-atmospheric level. The mass at the steady state temperature has increased, but the temperature has not. The “missing radiation” from the surface was used to increase the gas temperature to that previously enjoyed by the surface. As soon as that has be accomplished, the system is once again in equilibrium.

Only got partway thru the replies so if this has been said before ……”never mind!”.
W’s argument only applies if the absorptivity and emissivity (albedo) of the planet’s surface are identical. He is correct if his ideal atmosphere, where convection, conduction, adiabatic lapse rate (thus gravity) play no part, has zero absorptivity and emissivity. Also not stated and assumed (I assume) is that any H2O is inert, like the atmosphere, and must have zero heat of vaporization/crystallization, and absorptivity = emissivity.
If these apply W’s simplistic argument is correct and gravity cannot play a part but in the real world Willis has previously shown here that excess heat is transferred to the upper atmosphere by condensing water vapor in thunderheads and radiated into space to keep the Earth’s temp withing a narrow range. Brilliant Willis!!!!!!
Now looking at N&Z’s and HJ’s argument that gravity (adiabatic lapse rate) plays a part; the elevator explanation is: Assume that the air is dry. All other properties are the same. It warms from contact with the warmer surface. A warm bubble breaks away and rises. As it rises it cools thru expansion, radiating some of that heat energy, as long wave IR, into space or warming some of trace GHGs. (These then radiate some of that miniscule energy, as LWIR, into space as they cool.) As the cold air bubble sinks back to the ground it cools the surrounding warmer air and surface absorbing the remaining energy NOT radiated into space. So N&Z and HJ are correct; gravity plays a part in transmission of some energy into space.
Now add water vapor. As Willis explained previously, the amount of energy transferred to space thru LWIR is dramatically increased because of the large amount of energy released when the water vapor condenses into clouds, driving the clouds to ever higher altitudes and ever more efficient transmission of the released energy into space. N&Z and HJ are still correct but the overall contribution by gravity now becomes a far smaller proportion of the total heat removed, possibly insignificantly small.
BC

simpleseekeraftertruth says:
January 14, 2012 at 6:10 am ,
Your description was based on the idea of an IR photon from the sun being absorbed on the way in, and showing that 50% will be reflected back into space. The idea is that, in agregate, the co2 will have a cooling effect.
However, you have ignored the fact that most of the energy reaching the Earth from the sun is not in the IR, but in the visible spectrum. This bulk of energy goes straight through the CO2 and reaches the surface. It is then absorbed by the ground and the oceans and is emitted as IR. So, although the CO2 has intercepted the small amount of incoming IR and sent it back into space, there is a much larger flow of outgoing IR on which to act. This means the cooling effect is much less than the warming effect.

I’m not sure about lapse rate warming being the answer as lapse rate cooling in the convection cycle would tend to cancel it out however… does gravity (which can do work) add energy to the equation such that radiation in + work done by gravity = radiation out? (Where the heck does gravity come from anyway?)

Conservation of energy dictates that the amount of energy radiated from the Earth’s system must be equal to the energy it receives. Under the GHG hypothesis, it is argued that this balance occurs at a place called “top of atmosphere”, while any level below this is allowed to be at a higher temperature.
The gravity hypothesis must similarly involve a TOA radiation that is equal to the incoming radiation, and would allow that the temperature at the Earth’s surface be higher than this. Willis premise is that there cannot be a TOA radiating less that the surface, because to do so, the atmosphere would need to absorb outgoing IR, and without GHG’s it cannot do so.
But, if the lower atmosphere is warmed by the gravity effect, there would indeed by a temperature gradient, with temperature declining as you go higher. At this point, it could be imagined that there is a TOA higher up radiating the same amount of energy that is received from the Sun.
But. . .the crucial point is, these molecules in the atmosphere cannot radiate. To do so would require molecules of N2 and O2 to emit photons. As far as I am aware, they do not. The only way energy can leave the Earth is by radiation, and only the surface can radiate. This does lead to the violation that Willis states – the ground is supposedly warmed by a gravity compressed atmosphere, yet the energy can only leave the planet by radiating from the surface, which implies more energy radiating than being received.
However. . . What if we imagine some GHG’s are added to the atmosphere (just like our good ol’ Earth, actually). What happens if we suppose the gravity hypothesis to be correct? The ground is warmed by compression, and this extra outgoing radiation is absorbed by the GHG’s in the atmosphere. There can now be a TOA effect, radiating exactly the same amount of energy into space as is received.
Does this sound as if GHG’s and gravity both play a role in regulating the Earth’s temperature? Could be. The moral is – never thow out the baby with the bath water, Willis.

If I understand Jelbring, the elevator speech version of his paper is “the temperature at the surface has to be higher than at altitude due to the adiabatic lapse rate, even without greenhouse gasses”. He then (it seems to me) confuses that with the greenhouse effect.
Willis’ proof appears to me to be unassailable, but his statement that “they say that the combination of gravity plus an atmosphere without greenhouse gases (GHGs) is capable of doing what the greenhouse effect does” is only true for Jelbring because Jelbring re-defines the greenhouse effect as the adiabatic lapse rate.
Leonard Weinstein’s post above has the best explanation of the difference.

I think some seem to be missing the obvious part here. If you take a volume of gas at a given temperature and compress it, the same gas in a smaller volume now has a higher temperature, due to the compression and resulting density.
Let’s take a long thin tube of air in thermal equilibrium (100km long lets say), and extend if from the surface of the earth outward.
Gravity is going to compress the entire column of air down to about 17km. That compression heats the air and establishes the lapse rate, greatest density at the bottom and less density at the top. The part of the column of air that is most compressed (heated) is closest to the earth with the part at the top of the column not compressed much at all. The air will be denser and warmer closest to the surface (higher compression) gradually getting less dense and cooler as the altitude (less compression) increases. “Even though there is a non-uniform temperature distribution, the column of gas will still be in thermal equilibrium because the non-uniformity simply arises due to the decreasing density of the atmosphere with altitude.”
Now for the fun part. If this column of air is in a perfect insulator, it will be completely stable, warmer at the bottom transitioning to colder air at the top.
Under Willis’s steady state though, he is essentially placing a heating/cooling element at the bottom of the column of gas. This will act much like a pot of boiling water with convection cells rising and falling in response to the comparative temperature differences at the surface boundary layer. While the equilibrium temperature of the atmosphere won’t change, the atmosphere itself will be in constant dynamic change striving to reach equilibrium.
Willis’s heating/cooling surface will remain in equilibrium, emitting exactly as much radiation as it receives.
This by the way is a much better description of how our atmosphere actually works than the greenhouse gas theory.

“You are doing nothing but guessing and speculating, often in impossible directions. Gravity can’t run an engine of any kind. If it could, you’d have perpetual motion.”
Willis, you need to give what I wrote more thought than that! Does convection work without gravity? No! Gravity is a condition necessary, not a condition sufficient.
I am not a scientist but have experience in practical passive solar design. One can maintain water in an insulated tank at a warmer than average temperature using passive solar principles and convection by placing the collectors below the storage.
The poor emissivity of the bulk of gases in the atmosphere acts as the insulation.
The irrationality I posited was a semantic irrationality. Claiming an average temperature at the collector (surface) when what is being measured is the water in the insulated tank (air 6ft above the surface). Thus the average temperature of the surface needs to be lower than claimed because they are instead measuring the stored temperature.
This is actually pretty simple when you recognize accepted rules of radiation that something is as good of a radiator as it is as an absorber. In building insulation one does this by placing shiny non-radiative surfaces in the insulation space. The foil is hotter, approaching the insulated space temperature, and radiates less.
Assuming the average temperature of the surface is 288K by measuring air 6 feet above a convecting surface provides a one-way path for heat into the atmosphere that becomes trapped there. There is no convection process to deliver it back to the surface as in the solar collector system placed below the storage.
I think the only way you could disprove this is by actually measuring the surface, the real surface, and still come up with 288K. As a check using the NASA budget of 30% of solar energy transferred via convection one can calculate that as 84% of the greenhouse effect. Throw in a factor for the earth’s surface not being 1.0 but maybe more like .9, a dash of UHI, a pinch of cloud IR reflectivity, and maybe a spoonful of error resulting from weather stations favoring low altitude locations and you may have the recipe.
Keep in mind that its the diurnal cycle and perhaps the curavture of the earth that makes this happen. If the globe received it average radiation uniformly the passive solar water system would not work either.

There’s a cart/horse problem not mentioned previously. The constitution of an atmosphere is affected by chemistry- With a warming of the planet, much of the carbon in Venus’s rocks went into the atmosphere- cool the planet by other means, and much of Venus’s CO2 would wind up back in the soil. In other words, one could argue that Venus has a dense atmosphere because it’s hot, rather than argue that it’s hot because it has a dense atmosphere.

An addendum to the above. Most people apply an electric pump to their passive solar designs (making it a little less than passive) because they want the collectors on the roof and the insulated storage in the basement. So then convection works against you so you have to provide a pump for the transport of warm water to the basement during the day and a valve to limit convection of the warm water in the basement to the roof at night. But the lack of emissivity of the storage still makes it work.

One can’t have an atmosphere at 0K – absolute zero – because it would be a solid, not a gaseous atmosphere.
At any temperature above 0K the atmosphere must be radiating, and the energy it radiates must get replaced somehow, or it would cool and liquify, then solidfy.
In your model, where is the atmosphere getting its energy? What is its temperature? How much is it radiating?
Does this atmosphere have a lapse rate? Is it, or is it not warmer at the bottom of the pile than at the top? Why?
If we add more gas to this atmosphere will the difference in temp between the top and bottom of the atmospheric column increase, decrease, or remain unchanged?
In my limited experience with solving physics problems, one needs a complete, coherent model. Otherwise one gets silly, meaningless answers. I’ve never seen such a model in any discussion of the “greenhouse effect.” Why is that?

Thanks, Willis, for the nice post.
Bill Illis says:

What is the physics explanation for why temperatures of a gas/star/planet increase as it is gravitationally compressed?

If an object is truly undergoing gravitational collapse then you can have some gravitational potential energy being converted to other forms of energy (in particular, thermal energy). Hence, there truly is another source of energy besides the energy being received from the sun.

Why does matter do this?
I think the answer to this question will point to the answer about an atmosphere in gravitational equilibrium.

Yes…Comparison to this case shows why for gravitational collapse, you can truly have more energy coming out than you are receiving from the sun. However, for gravitational equilibrium, all that you can have is energy being moved around and, at the end of the day, you have to have only as much energy being emitted back out into space as is being absorbed from the sun.
So, the Earth is not undergoing gravitational collapse and hence it must be emitting ~240 W/m^2 back into space. And, indeed, measurements from satellites confirm this is what it is doing. The fact that the surface is emitting 390 W/m^2 has nothing to do with an internal energy source but is simply because some of the emissions from the surface are absorbed by the atmosphere, i.e., there is a radiative greenhouse effect.
erl happ says:

But the cooler latitudes in fact emit more energy than is acquired in solar radiation. The warmer latitudes emit less. The denser atmosphere increases the residence time and the amount of energy stored in the system, hence the temperature.
Last sentence is the elevator statement

And, one easily shown to be nonsense.
First of all, what we are interested in is the global energy balance. Yes, radiative energy does not balance locally because there is considerable movement of energy around on the Earth, as well as storage and release of energy. That is a good reason why we look at global energy balance and not local balance.
Second of all, your notion that some sort of energy storage can be invoked is not reasonable. What you would have to argue is that there is such a huge store of energy that the Earth can continuously emit 150 W/m^2 more than it absorbs without cooling down. Sorry, but this ain’t going to happen. To a good approximation, any energy storage that is occurring (e.g., due to plants converting sunlight into chemical energy) is balanced by energy release that is occuring (e.g., due to plants decaying). Also, the amounts involved are pretty small. For example, despite the fact that we are going through fossil fuel reserves much faster than they were created, we are only releasing about 0.02 W/m^2 of thermal energy by burning them, which is 4 orders of magnitude less than the 150 W/m^2 deficit.

…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.
OMG!..The Earth has no lid!…We urgently need to release the millions of degrees under the ground down there, according to Al Gore!

ferd berple says:

Mathematical proof that GHG cools the surface of planet earth
…

You are just embarrassing yourself. An atmosphere with GHGs doesn’t just emit radiation, it also absorbs radiation from the surface. And, in fact, it absorbs more from the surface than it emits back out into space. (It has to emit as much in total as it absorbs overall, but some of what it emits goes back to the surface, not out into space.)

There is no free lunch. If the GHG atmosphere is radiating, then there must be a reduction in radiation somewhere else.

And, what law of physics is this…and how does it pertain to anything being talked about?

The contributor known as wayne previously summarised my position on this issue which has been in my mind for several years as a very important aspect of the climate debate.
Willis did not address wayne’s version so here it is in my words:
[SNIP: vague, wandering, unscientific, and off topic. -w.]

hmmm… my elevator attempt above no doubt falls apart if convection stops, as it eventually will if no photons at all can ever be emitted, as indeed roy spencer points out. Isothermic. But that calls into question the usefulness of the model, as some have noted above. If the original papers had used this model, then fair game, but Tallbloke seems to suggest this was not the case. maybe a more interesting model would be to use just nitrogen and oxygen at earth ratio and pressure. Awful lot of it, so still significant emission despite low emmissitivity. Just a thought…

Willis said (to Crosspatch): “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.”
I don’t profess to any real knowledge of thermodynamics but isn’t this then postulating (a) an atmosphere with mass, (b) capable of convection and conduction, and (c) with its own localised temperatures and gradients (separate from the surface temperature, although no doubt coupled to it, with lags).
Why can’t such an atmosphere radiate? Suppose, instead of surrounding a planet, it was just a cloud of the (hypothetical) transparent gas, in space. Would there be no way of physically detecting it’s presence, outside the gas envelope itself?
I’m smelling an impossible premise here, somewhere.

The problem with ferd berple’s argument is that just because GHGs reduce the amount of surface radiation escaping to space, you can’t conclude that there is less surface radiation entering the atmosphere, and actually it turns out it has to be more because a GHG atmosphere has to be cooler than the surface due to the lapse rate (or gravity if you like).