Guest Post by Willis Eschenbach
A couple of apparently related theories have been making the rounds lately. One is by Nikolov and Zeller (N&Z), expounded here and replied to here on WUWT. The other is by Hans Jelbring, discussed at Tallblokes Talkshop. As I understand their theories, they say that the combination of gravity plus an atmosphere without greenhouse gases (GHGs) is capable of doing what the greenhouse effect does—raise the earth at least 30°C above what we might call the “theoretical Stefan-Boltzmann (S-B) temperature.”
So what is the S-B temperature, theoretical or otherwise?
A curious fact is that almost everything around us is continually radiating energy in the infrared frequencies. You, me, the trees, the ocean, clouds, ice, all the common stuff gives off infrared radiation. That’s how night-vision goggles work, they let you see in the infrared. Here’s another oddity. Ice, despite being brilliant white because it reflects slmost all visible light, absorbs infrared very well (absorptivity > 0.90). It turns out that most things absorb (and thus emit) infrared quite well, including the ocean, and plants (see Note 3 below). Because of this, the planet is often treated as a “blackbody” for IR, a perfect absorber and a perfect emitter of infrared radiation. The error introduced in that way is small for first-cut calculations.
The Stefan-Boltzmann equation specifies how much radiation is emitted at a given temperature. It states that the radiation increases much faster than the temperature. It turns out that radiation is proportional to absolute temperature to the fourth power. The equation, for those math inclined, is
Radiation = Emissivity times SBconstant times Temperature^4
where the Stefan-Boltzmann constant is a tiny number, 0.0000000567 (5.67E-8). For a blackbody, emissivity = 1.
This “fourth-power” dependence means that if you double the absolute temperature (measured in kelvins), you get sixteen (2^4) times the radiation (measured in watts per square metre, “W/m2”). We can also look at it the other way, that temperature varies as the fourth root of radiation. That means if we double the radiation, the temperature only goes up by about 20% (2^0.25)
Let me call the “theoretical S-B temperature” the temperature that an evenly heated stationary blackbody planet in outer space would have for a given level of incoming radiation in W/m2. It is “theoretical”, because a real, revolving airless planet getting heated by a sun with the same average radiation will be cooler than that theoretical S-B temperature. We might imagine that there are thousands of mini-suns in a sphere around the planet, so the surface heating is perfectly even.
Figure 1. Planet lit by multiple suns. Image Source.
On average day and night over the planetary surface, the Earth receives about 240 W/m2 of energy from the sun. The theoretical S-B temperature for this amount of radiation (if it were evenly distributed) is about -18°C, well below freezing. But instead of being frozen, the planet is at about +14°C or so. That’s about thirty degrees above the theoretical S-B temperature. So why isn’t the planet a block of ice?
Let me take a short detour on the way to answering that question in order to introduce the concept of the “elevator speech” to those unfamiliar with the idea.
The “elevator speech” is simply a distillation of an idea down to its very basics. It is how I would explain my idea to you if I only had the length of an elevator ride to explain it. As such it has two extremely important functions:
1. It forces me to clarify my own ideas on whatever I’m discussing. I can’t get into handwaving and hyperbole, I can’t be unclear about what I’m claiming, if I only have a few sentences to work with.
2. It allows me to clearly communicate those ideas to others.
In recent discussions on the subject, I have been asking for that kind of “elevator speech” distillation of Jelbring’s or Nikolov’s ideas, so that a) I can see if whoever is explaining the theory really understands what they are saying and, if so, then b) so that I can gain an understanding of the ideas of Jelbring or Nikolov to see if I am missing something important.
Let me give you an example to show what I mean. Here’s an elevator speech about the greenhouse effect:
The poorly-named “greenhouse effect” works as follows:
• The surface of the earth emits energy in the form of thermal longwave radiation.
• Some of that energy is absorbed by greenhouse gases (GHGs) in the atmosphere.
• In turn, some of that absorbed energy is radiated by the atmosphere back to the surface.
• As a result of absorbing that energy from the atmosphere, the surface is warmer than it would be in the absence of the GHGs.
OK, that’s my elevator speech about why the Earth is not a block of ice. Note that it is not just saying what is happening. It is saying how it is happening as well.
I have asked, over and over, on various threads, for people who understand either the N&Z theory or the Jelbring theory, to give me the equivalent elevator speech regarding either or both of those theories. I have gotten nothing scientific so far. Oh, there’s the usual handwaving, vague claims of things like ‘the extra heat at the surface, is just borrowed by the work due to gravity, from the higher up regions of the atmosphere‘ with no mechanism for the “borrowing”, that kind of empty statement. But nothing with any meat, nothing with any substance, nothing with any explanatory value or scientific content.
So to begin with, let me renew my call for the elevator speech on either theory. Both of them make my head hurt, I can’t really follow their vague descriptions. So … is anyone who understands either theory willing to step forward and explain it in four or five sentences?
But that’s not really why I’m writing this. I’m writing this because of the claims of the promoters of the two theories. They say that somehow a combination of gravity and a transparent, GHG-free atmosphere can conspire to push the temperature of a planet well above the theoretical S-B temperature, to a condition similar to that of the Earth.
I hold that with a transparent GHG-free atmosphere, neither the hypothetical “N&Z effect” nor the “Jelbring effect” can possibly raise the planetary temperature above the theoretical S-B temperature. But I also make a much more general claim. I hold it can be proven that there is no possible mechanism involving gravity and the atmosphere that can raise the temperature of a planet with a transparent GHG-free atmosphere above the theoretical S-B temperature.
The proof is by contradiction. This is a proof where you assume that the theorem is right, and then show that if it is right it leads to an impossible situation, so it cannot possibly be right.
So let us assume that we have the airless perfectly evenly heated blackbody planet that I spoke of above, evenly surrounded by a sphere of mini-suns. The temperature of this theoretical planet is, of course, the theoretical S-B temperature.
Now suppose we add an atmosphere to the planet, a transparent GHG-free atmosphere. If the theories of N&K and Jelbring are correct, the temperature of the planet will rise.
But when the temperature of a perfect blackbody planet rises … the surface radiation of that planet must rise as well.
And because the atmosphere is transparent, this means that the planet is radiating to space more energy than it receives. This is an obvious violation of conservation of energy, so any theories proposing such a warming must be incorrect.
Q.E.D.
Now, I’m happy for folks to comment on this proof, or to give us their elevator speech about the Jelbring or the N&Z hypothesis. I’m not happy to be abused for my supposed stupidity, nor attacked for my views, nor pilloried for claimed errors of commission and omission. People are already way too passionate about this stuff. Roger Tattersall, the author of the blog “Tallbloke’s Talkshop”, has banned Joel Shore for saying that the N&Z hypothesis violates conservation of energy. Roger’s exact words to Joel were:
… you’re not posting here unless and until you apologise to Nikolov and Zeller for spreading misinformation about conservation of energy in their theory all over the blogosphere and failing to correct it.
Now, I have done the very same thing that Joel did. I’ve said around the web that the N&Z theory violates conservation of energy. So I went to the Talkshop and asked, even implored, Roger not to do such a foolish and anti-scientific thing as banning someone for their scientific views. Since I hold the same views and I committed the same thought-crimes, it was more than theoretical to me. Roger has remained obdurate, however, so I am no longer able to post there in good conscience. Roger Tallbloke has been a gentleman throughout, as is his style, and I hated to leave. But I did what Joel did, I too said N&Z violated conservation of energy, so in solidarity and fairness I’m not posting at the Talkshop anymore.
And more to the point, even if I hadn’t done what Joel did, my practice is to never post at or even visit sites like RealClimate, Tamino’s, and now Tallbloke’s Talkshop, places that ban and censor scientific views. I don’t want to be responsible for their page views counter to go up by even one. Banning and censorship are anathema to me, and I protest them in the only way I can. I leave them behind to discuss their ideas in their now cleansed, peaceful, sanitized, and intellectually sterile echo chamber, free from those pesky contrary views … and I invite others to vote with their feet as well.
But I digress, my point is that passions are running high on this topic, so let’s see if we can keep the discussion at least relatively chill …
TO CONCLUDE: I’m interested in people who can either show that my proof is wrong, or who will give us your elevator speech about the science underlying either N&K or Jelbring’s theory. No new theories need apply, we have enough for this post. And no long complicated explanations, please. I have boiled the greenhouse effect down to four sentences. See if you can match that regarding the N&K or the Jelbring effect.
w.
NOTE 1: Here’s the thing about a planet with a transparent atmosphere. There is only one object that can radiate to space, the surface. As a result, it is constrained to emit the exact amount of radiation it absorbs. So there are no gravity/atmospheric phenomena that can change that. It cannot emit more or less than what it absorbs while staying at the same temperature, conservation of energy ensures that. This means that while the temperature can be lower than the theoretical S-B temperature, as is the case with the moon, it cannot be more than the theoretical S-B temperature. To do that it would have to radiate more than it is receiving, and that breaks the conservation of energy.
Once you have GHGs in the atmosphere, of course, some of the surface radiation can get absorbed in the atmosphere. In that case, the surface radiation is no longer constrained, and the surface is free to take up a higher temperature while the system as a whole emits the same amount of radiation to space that it absorbs.
NOTE 2: An atmosphere, even a GHG-free atmosphere, can reduce the cooling due to uneven insolation. The hottest possible average temperature for a given average level of radiation (W/m2) occurs when the heating is uniform in both time and space. If the total surface radiation remains the same (as it must with a transparent atmosphere), any variations in temperature from that uniform state will lower the average temperature. Variations include day/night temperature differences, and equator/polar differences. Since any atmosphere can reduce the size of e.g. day/night temperature swings, even a transparent GHG-free atmosphere will reduce the amount of cooling caused by the temperature swings. See here for further discussion.
But what such an atmosphere cannot do is raise the temperature beyond the theoretical maximum average temperature for that given level of incoming radiation. That’s against the law … of conservation of energy.
NOTE 3: My bible for many things climatish, including the emissivity (which is equal to the absorptivity) of common substances, is Geiger’s The Climate Near The Ground, first published sometime around the fifties when people still measured things instead of modeling them. He gives the following figures for IR emissivity at 9 to 12 microns:
Water, 0.96 Fresh snow, 0.99 Dry sand, 0.95 Wet sand, 0.96 Forest, deciduous, 0.95 Forest, conifer, 0.97 Leaves Corn, Beans, 0.94
and so on down to things like:
Mouse fur, 0.94 Glass, 0.94
You can see why the error from considering the earth as a blackbody in the IR is quite small.
I must admit, though, that I do greatly enjoy the idea of some boffin at midnight in his laboratory measuring the emissivity of common substances when he hears the snap of the mousetrap he set earlier, and he thinks, hmmm …
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.
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.
great article.
….my tomatoes still die when the temperature goes below freezing.
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…’..”
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.
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!
.
.
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! (:-
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.]
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)?
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.]
Anteros says:
January 13, 2012 at 10:22 pm
Apologies for the lack of clarity, Anteros, that’s the amount after albedo reflection of 30% of the incoming.
w.
alex says:
January 13, 2012 at 10:36 pm
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.
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…
beaker says:
January 13, 2012 at 10:42 pm
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.
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.
Michael Bergeron (@zerg539) says:
January 13, 2012 at 10:50 pm
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.
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.
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).
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.
“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.
@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.
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.
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.
“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.
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.
“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)
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!
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.
Willis: consider the difference between ground frost (radiative cooling) and air frost (radiative cooling + convection).
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
True
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.
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.
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.
If so, there would be a constant flow of heat from the warmer atmosphere to the surface. Not physically possible.
Thanks, much appreciated,
w.
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
Nick Stokes says:
January 13, 2012 at 9:57 pm
Thanks, Nick, that is significant to me.
steven mosher says:
January 13, 2012 at 11:33 pm
Thanks, mosh, your vote is significant as well.
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.
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 😉
NoIdea says:
January 13, 2012 at 11:09 pm
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.
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???
“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
crosspatch says:
January 13, 2012 at 11:40 pm
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.
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.)
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.
“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?
A slight correction to make your statements work within the laws of Thermodynamics:
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.
At Night there is a net radiation by the atmosphere back to the surface.
(During the day, there is no heating, only a slowing of heat loss, as net radiation is outward)
• As a result of absorbing that energy from the atmosphere, the surface is warmer at night than it would be in the absence of the GHGs.
So the effect is that the night time temperature is higher and the day time temperature is cooler (due to the thermal mass of the air & oceans)
However, there is the same contradiction with the greenhouse effect.
Because there is ALWAYS more energy radiating from GHG out to space, (since emissions go equally in all directions, and the geometry of a sphere means just more than 50% is outward) this means that IF the planet gets MORE energy to the surface from GHG then 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.
It matters not how many “layers” of GHG you have, Once equilibrium is established, more than half is always heading to space. The real world atmosphere is turbulent, but that standard explanation is always worked out on a static atmosphere.
It seems to me that there is a maximum effect, and once this is reached, there can be no further warming. Everyone seems to forget that classic climate theory (from textbooks prior to 1988) was that the atmosphere warms by convection and cools by radiation.
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.
And the air.
GHGs just absorb in certain bands of outgoing IR and make the air warmer. That makes the entire atmosphere radiate more, half the time right back down to the surface. An atmosphere sans GHG would still radiate, just less.
How would the atmosphere get warm without GHGs? Conduction and convection as others have mentioned.
The assumption made in the post is ALL of the energy absorbed during the day is immediately radiated back to space, and so we seem to have trouble explaining a higher than expected temperature.
If a significant fraction of the solar energy is absorbed, it may take time for it to be radiated away. Consequently, the temperature will rise until balance occurs. When the Earth is significantly warmer the total output matches the total input, accounting for delayed release of input energy. One mechanism for absorption of solar energy that cannot be immediately re-radiated is ocean mixing. Only the surface will radiate to space. The solid surface of Earth can act in the same way – as an energy sponge. The delay in reradiation must raise the temperature of the Earth to achieve balance.
To illustrate: Try walking barefoot in a freshly paved parking lot in Florida some summer.
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.
Bill Hunter says:
January 13, 2012 at 11:53 pm
Um … er …
Ah … well … eee …
Bill, I don’t know how to be polite about this, but I assure you it is meant well. Your comments are exactly what I requested people to refrain from, vague suppositions. I said that I wanted science and substance.
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.
Folks, let’s stick to the hard science, could we?
All the best,
w.
“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.
@willis/crosspatch
Of course a gas can radiate energy, whether it has GHGs or not. If conduction/convection increases its temperature, it radiates more.
Why should gases not obey thermodynamic principles?
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.
Willis,
Thank you for showing the incorrectness of the Nikolov and Zeller idea in such a simple and straightforward way.
Meanwhile Robert G Brown’s article on WUWT showed some of the true complexity of calculating the surface temperature distribution of the Earth – no N&Z in sight!
“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…
Since both N2 and O2 absorb and radiate in the UV region there is no such thing as a transparent non-GHC atmosphere. This is a good account of gas radiation: http://www.heliosat3.de/e-learning/remote-sensing/Lec7.pdf
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 ……
Gravity, plus the Sun, water vapor, rain, runs all the hydro power. The atmosphere is a little more diffuse, and harder to extract work from, but it does heat up as it falls down.
By the way, O2 and N2 seem to have significant IR absorption bands, considering their proportion of the atmosphere, was your hypothetical atmosphere also hypothetical Willis?
Alexander Feht says: January 14, 2012 at 12:55 am
“Stefan Boltzmann was one man, his last name was Boltzmann, his first man was Stefan”
No, Boltzmann’s name was Ludwig. Joseph Stefan was his predecessor as Professor of Theoretical Physics at the University of Vienna.
He was a highly respected scientist in his lifetime, and had been appointed to the most eminent scientific chair in the Austrian Empire. He had been received by the Emperor, shortly before his death.
To correct some misunderstanding:
Yes, all gases will emit and absorb energy, but for non GH gases the effect is small over thermal ranges (what we associate with earth temperature ranges). For Oxygen and Nitrogen, only collisions provide the dipoles needed for thermal absorption and emission. This is significant only at high pressure and temperature (where there are more collisions). Since the atmosphere is mostly non GH gases, even though this effect is small, it is by no means zero, but it is maybe less than 1% of that of the GH gases. Thermodynamics means that heated gases must cool to that of their surroundings. They do this by mainly by expanding, which is the cause of convection.
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.
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.
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.
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.
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.
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
Alexander Feht says:
January 14, 2012 at 12:55 am
Alexander, the amazing thing about you is that your bull is so convincing I always have to shake my head. Here’s what Wikipedia says about what they call the “Stefan-Boltzmann law”, complete with hyphen:
Go away, sir, your impudence knows no bounds. You haven’t a tenth of the knowledge you claim.
w.
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.
Alexander Feht says:
January 14, 2012 at 12:55 am
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
Come on. Jožef Štefan was a full professor at the University of Vienna, he has discovered (and published) that energy flux of black body radiation is proportional to T⁴ in 1879 (based on measurements of French physicists Dulong and Petit). Ludwig Boltzmann was his student, he earned his PhD under his supervision in 1866 (the same year prof. Štefan became Director of the Physical Institute) and has extended Štefan’s results in 1884 to grey body radiation (at that time he was professor of Experimental Physics at the University of Graz). Also, Boltzmann’s beard was much thicker, therefore we are most definitely talking about two separate persons.
It is not a shame to be ignorant, but it is to pretend to know.
I asked an alarmist a very simple question recently. What emites/gives off IR, a block of ice, a bottle of water or a pot of boiling water? He (I assume so based on name) answered water vapour. He could not grasp the fact that ice emits IR. And then accused me of asking him a “trick” question!! This is the level of scientific stupidity anyone equiped with even a basic knowledge physics has to deal with in this “debate”.
Apologies for the long comment, there’s quite a lot to deal with here.
Nikolov and Zeller’s extended conference poster ‘The Unified Theory of Climate’ was originally posted at the Talkshop a day before it was posted here at WUWT. On my website Willis says of it:
” I find the work of Nikolov and Jelbring to be laughable. I cannot even understand Nikolov. I invited him to state the core of his theory in a few sentences, since his writing is unintelligible….. He talks about atmospheric sponges and bowls, I can’t make sense of it…..As a result, I can’t tell if Nikolov’s theory violates the laws of thermodynamics.”
I ran a word search on the text but could not find any references to “atmospheric sponges and bowls”. Willis often complains that people argue against what they think he said rather than directly quoting him. I think he should follow his own advice and extend the same courtesy to others.
I also republished Hans Jelbring’s 2003 E&E paper ‘The Greenhouse Effect as a function of atmospheric Mass’ on which Hans Jelbring was kind enough to engage with Talkshop contributors.
Willis didn’t place any comment on that thread but said elsewhere on my website:
“Here’s the short proof, by contradiction. Jelbring proposes that a perfectly transparent, GHG-free atmosphere will raise the temperature of a planet’s surface well above the S-B temperature obtained from the average impinging solar radiation. (This is the situation of the Earth, for example.)
But if that is so, and the surface is somehow warmed above the S-B temperature, and the atmosphere is transparent, then the surface must radiate more energy to space than it is receiving, which is clearly impossible. Q. E. D…..I said the same thing to his face—his theory breaks the laws of thermodynamics.”
Once again Wiillis is doing what he tells other people not to do; arguing about what he thinks Dr Jelbring said instead of quoting him: Here is a brief excerpt from the beginning of section 2.1 where Hans Jelbring sets up the definitions for the model Earth in his 2003 paper. It is sufficient to dismiss Willis’ ‘proof’:
“A simplified model of Earth will be considered. The model planet does not rotate. It
neither receives solar radiation nor emits infrared radiation into space.”
Hans Jelbring tells me he has never met Willis face to face. To help resolve this apparent contradiction Willis could tell us when and where he
“said the same thing to his face—his theory breaks the laws of thermodynamics.”
Perhaps Willis is speaking figuratively, and is referring to an interaction with Hans Jelbring on the old CS email list? Before banning himself from the Talkshop because I ‘banned Joel Shore’ Willis should have engaged directly with Hans Jelbring on the same page where the entire E&E paper is published. That would have been the more scientific (and courteous) thing to do in my opinion.
Willis complains that I am preventing Joel Shore from expressing his scientific beliefs. This is incorrect. I won’t let Joel engage in the various very active and nicely undisrupted threads we have running at the moment but instead offered him a guest post where he could set out his scientific position formally on a thread of his own. It’s a strange kind of censorship which offers the ‘victim’ the microphone and points the way to the stage. According to Willis:
“Joel may have a hundred reasons not to want to invest the time and effort in a guest post.”
Joel himself says:
“I’m not particularly interested in doing a guest post. I have my hands full just trying to respond to all the misguided people over at WUWT and, with classes starting again tomorrow, I won’t be able to allow this time sink to continue for too much longer.”
Considering the much bigger loudhailer Joel has here at the biggest climate site in the world, it’s understandable why he would think it more important to spend his time here rather than on a website which gets around 1/20 of the traffic WUWT does.
The benefit to the Talkshop is that it enables its contributors to continue calmly discussing the merits and demerits of the properly set out scientific positions in the papers kindly provided by
Nikolov and Zeller
Hans Jelbring
Gerlich and Tscheuschner
R.P Sheehan
Johann Josef Loschmidt
Coombs and Laue
Roman et al.
Velasco et al.
William Gilbert
and
Dean Brooks
Cheers
TB.
[SNIP: No, there’s not a lot to deal with here, Roger, you have your blog for that. As I clearly requested above, we are dealing with two things:
• Your contribution of an elevator speech explaining Nikolov/Jelbrings work. Since you have not given one, I assume you don’t understand them.
• Your demonstration that my proof is wrong.
As a result, I have snipped your complaints about me and what I have done and what I understand or don’t understand. You can whine about that with your friends on your own website. Here, we’re discussing a couple very particular scientific questions. Come back if and when you are willing to give us your elevator speech or show my proof is wrong.
Sadly, but firmly,
w.]
[NOTE: Tallbloke’s post has been restored in its full glory. -w.]
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.
Alexander Feht and others,
If all gasses are capable of absorbing radiant energy and if all gasses are capable of emitting at least a small amount of energy by radiation, then presumably all gasses are, to at least a small degree, greenhouse gasses. So any mixed atmospheric gas, for instance one composed exclusively of N2, O2 and Ar, will absorb some component of shortwave radiation and emit longwave radiation. Therefore there will be a greenhouse effect even if it is not large.
The question then would be whether these gasses are or are not capable of sublimation from a liquid or solid state at the Earths blackbody temperature. If the “gasses” are capable of existing in a gaseous phase at this temperature then there will be an atmospheric greenhouse effect even though it may be a small one. So logically the temperature of the gas at the earths surface must be greater than the blackbody temperature.
It would therefore seem that the greehouse effect attributable to the usual suspects (primarily H2O, CO2, O3, CH4) is less than 100% of the full greenhouse effect.
Could someone please explain where the above is incorrect?
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?
Willis,
Thank you for your intellectual honesty: your critiques of the warmist theory is not blindfolding you when physical reality and valid physical laws have to be taken into account. So, for two reasons I appreciate the title that you gave to this post: a game of words and a call for seriousness.
Warming is not only due to GHG. Some of the Incoming solar radiation is absorbed by nitrogen, oxygen, CO2 and water in the UV/visible range, contributing to a temperature increase of the air mass.
In the atmosphere, there are enough components to ensure a long wave radiation according to SB law.: GHG (CO2, water, methane, nitrogen oxide), liquid water in form of clouds (cloudiness is about 60% of the Earth surface), and aerosols (liquids and solids).
Please have a look at this simple two layers model which is just assuming the existence of an atmosphere, regardless of its composition: http://climate.mr-int.ch/TwoLayersClimateModel.html
After having taken various feedback mechanisms the calculated surface temperature increase due to GHGs since the beginning of the industrial era is approx. 0.4°C, quite below values cited in most papers about warming, in particular by the IPCC. But some warming takes place thanks (or because of) GHGs. For any doubling of the atmospheric CO2 concentration a temperature increase of 0.5-0.6 °C can be expected.
A simple (simplistic?) model giving reasonable orders of magnitude, and satisfying the golbal heat balance requirement.
Alexander Feht:
I don’t usually quote Wikipedia, But Ludwig Boltzmann’s superviser/tutor was Josef Stefan.
And I agree with other, all gases radiate EM if above 0K. It can’t be ignored if a “greenhouse gas”-free atmosphere is being hypothesised.
I forgot to mention; This is my Elevator speech. Only the Elevator was very fast.
Wow–this is something that might be put to the test–maybe even by a college-class or a high-school science fair project! (If the kid can get a grant.)
[COMMENT: Roger, I use the MODIS IR emission library for this question. It gives the same value as Geiger, .98 or so – w.]
I found this thread somewhat interesting until I read tallbloke’s rebuttal just above. Willis is being disingenuous, setting up a strawman to knock down and thus not engaging with the actual theoretical model he claims to be taking apart.
[SNIP: If you wish to accuse me of being disingenuous, quote my words or go home. I won’t stand for this kind of vague nasty accusation, that’s a slimy tactic. And if you believe a man like Tallbloke, who censors scientific opinion that he disagrees with, you are an idiot. -w.]
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… ?
Steve C says (January 14, 2012 at 12:45 am): “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.”
I assume W’s “transparent atmosphere” is a conceptually ideal experimental tool much like the frictionless planes and weightless pulleys I remember (vaguely) from physics class. Granted it may not apply to any real atmosphere, but we’re talking about a narrow thought experiment, not real life.
Somehow, I have difficulty with the concept of a perfectly transparent atmosphere, one that does not absorb radiation. As has been pointed out, neither could it emit radiation. An interesting concept, but not available in this particular galaxy.
Genghis is closest to my thoughts on this. The atmosphere is going to sort itself out to the adiabatic lapse rate temps, and the radiative “surface” is going to rise, warmer below, cooler above.
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.
Lapse rate indeed has nothing to do with elevation, but density does. A denser atmosphere will be thicker, for any gas. We think of elevation in terms of “up,” but a better term for our purposes would be “depth.” Starting at the top of the atmosphere, zero depth, zero density, the deeper you go, more more distance that lapse rate has to work, thus higher temperature.
Willis [NOT SO. Repeat after me, “GHG-free atmosphere”. The surface is the only thing that can radiate. w.]
Since both the surface and the atmosphere consist of atoms and molecules, it might help if you explain the fundamental difference between them that allows the surface to radiate, but not the atmosphere.
You must envision some solid materials that emit far infra red that passes unchanged through the non-GHG atmosphere. They are all around us. The commercial FLIR camera will detect temperature differences that show as lifelike images via a microbolometer detector, into the tens of microns wavelength range at least. The “image” can travel many kilometers through the atmosphere. The cameras perform better when the interior optical path, where the image is smaller and more concentrated after passing through lenses, is filled with dry nitrogen gas to remove absorbers CO2 and H2O (gas). The idealised FLIR camera would seem to be a working example of your preferred elevator in action.
For a model where an atmosphere is suddenly introduced, there would be an equilibration period. Depending on the precise method, there should be heating from gravitational compression. Then there would be cooling, because the introduction process is a once-off, not a continuous one. The cooling cannot reintroduce hot material by conduction or convection to lead to an overall gain because the external heat sorce has a constant input in the first approximation.
BTW, it would be interesting to know if there is a compilation of global surface temperatures taken a few meters BELOW the surface. We seems to be fixated on certain concepts because Stevenson screens with thermometers were a meter and a bit above the surface.
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.]
shot in the dark.
[SNIP … I specifically asked people not to shoot in the dark. -w]
Anyway i hope that helped.
[It didnt. -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.
Is there a virtual bar where Willis, TB and JS can line up at the bar and sink a few whiskies and settle their differences? Such’he said/you said/they said’ squables are a distraction from the far more important AGW debate. Its good to disagree and debate, its not good to throw your toys out of the pram.
[SNIP: read the instructions. Elevator speeches and disproofs only. -w.]
And discussing the chemical composition of methane, CH4, with the same person in my previous post claimed CH4 had “4 carbons”…and was “interesting”. I think CH4 having “4 carbons” would be interesting to many.
[snip . . off topic . . kbmod]
[SNIP: read the instructions. Elevator speeches and disproofs only. -w.]
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??
Steve (Paris) says:
January 14, 2012 at 2:48 am
“Is there a virtual bar where Willis, TB and JS can line up at the bar and sink a few whiskies and settle their differences? Such’he said/you said/they said’ squables are a distraction from the far more important AGW debate. Its good to disagree and debate, its not good to throw your toys out of the pram.”
Well said, Sir. However, responsible bar staff would eject – at least two of them – for being excessively drunk wih their own importance
[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. -w.]
The thought experiment is interesting, but its usefulness may be limited by its own constraints.
The issue is defined in terms of surface temperature, and not temperature of the gas.
This ideal transparent gas can be warmed from the surface, and this means gas temperature above the surface could rise above the surface temperature. All we need is a day/night temperature profile at the surface, and convection to selectively warm the gas at higher levels towards the higher daytime surface temperature. This could eventually settle with the almost the whole atmosphere at the highest surface temperature with a very slim Temperature profile near the surface due to conduction.
Energy is conserved as the gas is a perfect insulator (constrained to not radiate at any frequency).
I’m not sure whether this thought experiment adds much to the debate. As I understand things, all matter will emit photons at certain frequencies so long as electrons are excited and then drop to ground state. The ideal non-emitting atmosphere sounds unphysical.
There may be more productive thought experiments if we were to focus more on the kinetic theory of temperature and pressure.
Cheers – I’m now off to the football (soccer) to observe other examples of kinetics.
“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.
I think that the planet has to be considered as a whole – including its atmosphere – and that it must obey the laws of thermodynamics regardless of energy transport mechanisms. I have tried the following as a mind clearing exercise:
“Considering the entropy of the planet as a whole, including the conductive effects of the surface – gas boundary and with calculations performed within a boundary high above the top of the atmosphere, the lapse rate acts to maximise entropy, and minimise enthalpy, in a near – equilibrium thermodynamic system that constantly seeks equilibrium as a consequence of rotation. the laws of thermodynamics subsume the effects of all energy transport mechanisms – conduction, convection and radiation.”
I think that he implication is that only insolation, gravity, rotation and the mass of the atmosphere are responsible for “climate”, and that doubling, tripling or whatever the mass of CO2 will have a negligible effect on the total mass of the atmosphere, and hence would not lead to any measurable effects on the “climate”.
I am not sure if the “total mass of the atmosphere” should read (the bulk specific heat of the atmosphere”
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.
Willis – I need to think more about your explanation, so I may (or may not) come back again some time later.
As a first comment, it seems to me that your explanation of why N&Z are wrong can equally be applied to greenhouse theory.
If all energy leaving the earth is radiated from the surface, then, by your own explanation, greenhouses gasses cannot warm the surface, as all additional warming would be radiated out into space to preserve equilibrium at the top of the atmosphere and surface temperatures would quickly return to pre greenhouse levels.
Something may be wrong with your facts or with you analysis, me-thinks.
Never-the-less, I almost enjoy your posts.
[SNIP: read the instructions. Elevator speeches and disproofs only. -w.]
Please forgive me.
What I meant to say was …… that I almost ALWAYS enjoy your posts.
[SNIP: read the instructions. Elevator speeches and disproofs only. -w.]
Willis – just a quick, second comment.
I suggest that you think some more about how heat is transferred around the planet and up and down in the atmosphere, before being radiated out into space.
And a request for clarification – is heat radiated out into space directly from the surface or from the top of the atmosphere?
How do these two factors mesh with temperature on the surface, the near surface where it is measured, and the top of the atmosphere?
How does the lapse rate fit in and how is that caused?
Willis is correct…if the atmosphere cannot absorb or emit IR, then the surface must emit thermal radiation at the same average rate as it absorbs solar radiation, which then (through the S-B relationship) yields a much lower average energy-equilibrium temperature than that observed.
Conduction into the ground or to the atmosphere does not alter this fact. Conduction might change the timeline if the ground or atmosphere are not at the same temperature as the surface, but eventually the average temperature of the surface must correspond to the average rate of solar absorption, since IR emission by the surface is the only way for the planet to cool in the face of solar heating (in the absence of a GHE).
As I have discussed on my blog, the observed temperature lapse rate of the atmosphere only describes how temperature CHANGES with height *IF* the atmosphere is convecting. It says nothing about what the temperature will be, in an absolute sense, which is an energy budget issue. If the atmosphere cannot absorb/emit IR, it would become isothermal, and all convection would cease. The greenhouse effect is what destabilizes the troposphere (by cooling the upper layers) and enables convective overturning. Without the GHE, we would not have weather as we know it.
I think many commentators are confused because they have heard or read the somewhat loose statement ‘All substances above absolute zero emit electromagnetic radiation’. This is certainly true for solids and liquids but it is NOT true for low density gases in our atmosphere. At atmospheric pressures gases absorb and radiate in specific spectral lines. Let me clarify, this is not just my opinion, this is an empirical result based on measurement (no models involved). Gases such as oxygen and nitrogen do absorb (and emit) at short wavelengths but not perceptibly in the long wave infrared where the greenhouse effect is important.
Kwik says: January 14, 2012 at 2:08 am “Are you saying I cannot heat Nitrogen?”.
No, Kwick, this means that you cannot heat nitrogen with long wave infrared radiation. You can heat it, as you describe, by putting it in a bottle and immersing the bottle in hot water – but not by LWIR radiation.
As I say, these things are confirmed by actual measurements. The following graph of the spectral distribution of downwelling (‘back’) radiation at the earth’s surface is very informative in this respect. Note that there is no typical blackbody distribution, instead radiation comes back from the atmosphere in specific spectral bands. There is no contribution from oxygen or nitrogen. Notice the dominant input from CO2 – the clear ‘fingerprint’ of CO2 in ‘back radiation’.
http://scienceofdoom.files.wordpress.com/2010/04/longwave-downward-radiation-surface-evans.png
Again – these are measurements, not models.
So, when Willis talks of a transparent GHG-free atmosphere he postulates an atmosphere that is not going to absorb radiation – and if it doesn’t absorb then it doesn’t emit – Kirchoff’s Law,
Is that clear?
@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.
Solids absorb and radiate in a black body manner because of there electron structure gives near continuous energy levels. Gas however do not interact with radiation fields unless the energy of the radiation corresponds to an discrete energy level of the molecule most the vibration modes are in the IR most of the atomic levels are in the visible or higher energies. Green house gases have vibrations modes in the IR and absorb and radiate.
Now come on this is basic physics.
The adiabatic lapse rate which this thread is talking about only gives the temperate change between the top and bottom of atmosphere. If the earth temp is -18C then the top will be a lot lower.
It tells us nothing on its own about the surface temperature.
Paulus
[SNIP: read the instructions. Elevator speeches and disproofs only. Stick to the topic. -w.]
Willis,
As a final comment tonight, may I suggest that you put aside all that you have learnt about greenhouse theory and just read the N&Z paper and see what it actually says.
[SNIP: If you understand it, give us the elevator speech. If not, why are you posting? w.]
[SNIP: read the instructions. Elevator speeches and disproofs only. -w.]
subscribe
[SNIP: read the instructions. Elevator speeches and disproofs only. -w.]
Mouse fur, 0.94
—–
Wow, thats soo cool, mice are soo cute.
Wanna add few remarks:
[SNIP: read the instructions. Elevator speeches and disproofs only. And mice. Mice are cute. -w.]
[SNIP: read the instructions. Elevator speeches and disproofs only. And mice. Mice are cute. -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.]
Let’s take a step back.
[SNIP: No, let’s not. Read the instructions. Elevator speeches and disproofs only. -w.]
Like Willis, I found Nikolov & Zeller’s poster, well, inscrutable. And I confess to being appalled at how many arguments on this thread are so clearly based on violating conservation of energy.
But anyone who has even a nodding acquaintance with tallbloke’s evenhandedness on the one hand and Joel Shore’s often ill-mannered thread monopolizing on the other should be able to appreciate that, not blessed with the moderator manpower that Wattsupwiththat enjoys, tallbloke’s choice to segregate Joel Shore’s output in a separate thread was a reasonable solution to the problem, brought on by Joel Shore, of how to avoid intolerable disruption but preserve open discourse.
I personally have benefited greatly from tallbloke’s blog, and I commend it to everyone’s attention.
[NOT SO. Repeat after me, “GHG-free atmosphere”. The surface is the only thing that can radiate. w.]
You keep saying that, but it’s BS.
[SNIP: No, it’s not bs, it’s called science. -w]
[SNIP: read the instructions. Elevator speeches and disproofs only. -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]
OK Willis, I’ll bite.
Daytime;
Consider a photon leaving the sun in the IR absorption band of CO2.
[SNIP- I’m talking about a GHG-free atmosphere, why are you discussing CO2? -.w]
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.
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.]
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.]
I doubt that these novel theories are correct since they sound to me like perpetual motion machines, but there are two sources of energy that would have to be ruled out or at least quantified, the rotation of the planet and tidal effects, since these could perturb the atmosphere and keep the machine from running down. Instead, the orbit of the moon, and the speed of the earth’s rotation runs down.
That being said, it sounds like a theory people want to believe.
Willis,
Of course you are correct. Not sure how many you will help to understand this simple concept, but I applaude your efforts. I become too frustrated when I try to do this sort of thing.
Too bad about Tallbloke; he is supporting nonsense and behaving like Tamino…. a bad combination.
Willis, what is the temperature of the atmosphere as due to difficulties in losing energy it doesn’t seem well constrained?
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.]
First of all I think this deserves a historical perspective. The reason the GHG-less atmosphere became a discussion point is because it highlights the claims of N&Z. If gravity/conduction/convection are to replace the GHE then they should do it when no GHGs are present.
Willis is absolutely correct that this simply can’t work. I initially tried to find some way to make N&Z work myself. I failed and I admit it.
However, there is something very important to take out of the N&Z paper. If one follows it to its obvious conclusion one finds that, yes, GHGs are required, but, it only takes a modest amount of GHGs to provide the MAXIMUM GHE. That’s why N&Z found so many planets temperature can be determined by a simple formula. They all have reached the maximum GHE. Hence, the addition of more GHGs will have no impact on the temperature.
One possible reason for this has to do with the turbulence of gases. The turbulence mixes the gases very well and drives the heavier gases like CO2 to greater altitudes. Since the GHE is essentially determined by the height of the effective radiating temperature, that height is almost immediately quite high. This also means that additional CO2 has almost no effect. The basic reason for this has to do with gravity placing bounds on the atmosphere.
Think of a basketball. I can fill it with a little air and the structure does not change much. Put in more air and it gets a little more firm but still stays pretty much the same. I have to put in a lot of air to get the ball to expand to any degree. Gravity puts the same general limits on an atmosphere. Clearly, not as much as my analogy but along the principle.
As a result the GHE becomes a function of pressure (gravity and mass) just as N&Z stated. However, some GHGs are required.
[Richard, thanks … but if you could boil that handwaving down to an elevator speech, I might be able to understand what you are saying. Leave out the basketballs, and explain the science of what you claim N&Z say is happening. -w.]
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
Wills. I can see a fairly easy way to prove or disprove the thesis. First a thought experiment and then a real one.
You and most folks only talk in terms of radiative theory when talking about temperature but that is not the only way that energy is exchanged.
Lets say that the sun is shining and the atmosphere is 100% transparent to infrared energy. We have to think about what is actually happening when the sun shines on a surface. Speaking in simple terms a photon in the visible spectrum (say 550 nanometers) has energy x. That photon strikes a surface that is capable of absorbing that energy x. This raises the temperature of a single molecule by y. Since this is happening en masse, you would do a summation of x and y and eventually you get the rise in temperature of the surface as described in the S-B equations.
There is a lag time between absorption and emission of energy, depending on many factors but between the absorption time T and the emission time T1, there is time for elastic collisions between the molecules of the surface, and the molecules of the non IR emitting atmosphere above it. These elastic collisions increase the energy of the molecules, and thus the temperature. Since the molecules cannot radiate in the infrared anymore than they can absorb energy in the infrared, the temperature of the atmosphere rises and via convection, the energy absorbed by the molecules is spread through the same elastic collisions between molecules. Thus we now have a mechanism whereby the temperature of the atmosphere rises without any resort to radiative theory at all.
This is very easy to test. Take a cylinder of air without any GHG’s in it. The cylinder needs to be to be at say 25c. At the bottom of the cylinder you have a radiative surface that you raise in temperature to say 75c, which is close to what the temperature of the ground would be with the sun shining directly down on it. Use multiple temperature probes at 50 cm intervals from the bottom of the cylinder to the top.
If this hypothesis is true you will se a temperature gradient between the first probe at 50cm and subsequent ones. As convection takes hold due to the gradient, eventually the temperature of the gas will rise to the temperature of the emitting surface, and this is without any resort to GHG’s.
The reverse would happen at night with the atmosphere transferring energy to the ground and with nothing more than mechanical energy equations I can describe an atmosphere above the S-B average temperature.
So the elevator pitch is that we can describe a atmosphere with no GHG’s that is above the S-B temperature by resorting to nothing more than equations of mechanical energy transfer.
What is wrong with this picture?
[Thanks, Dennis. If as you claim the atmosphere is above the S-B temperature and the surface is still at S-B temperature, heat will be constantly flowing 24/7 from the warmer atmosphere to the cooler surface … and that violates conservation of energy. -w.]
Atmospheric Greenhouse Effect
Both sides of the argument generally stated miss the basic point of an atmospheric greenhouse gas causing a higher ground temperature. In order to understand what is occurring, you first have to …
[SNIP: Read the instructions, stick to an elevator speech for Nikolov or Jelbring, or a falsification of my proof. 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.]
[SNIP: 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.]
[SNIP: Read the instructions, stick to an elevator speech for Nikolov or Jelbring, or a falsification of my proof. Thanks, -w.]
I’m convinced you’re right, Willis. The simple energy conservation is enough. Roy Spencer & many others agree.
Willis & others should continue to be patient. Everyone can’t be convinced. I feel fortunate for a good thermo education & work experience to follow most of this — at least in general. Coal-fired boiler design (especially in radiant boilers) has to take into account radiation effects of H2O & CO2 in the flue gas.
Why not test the data?
There is a recent statistical method that can be used to separate cause and effect from multiple interacting variables. Originally developed for economics, this technique looks like a possible way forward to resolve the cause and effect climate question.
http://en.wikipedia.org/wiki/Vector_autoregression
Vector autoregression (VAR) is a statistical model used to capture the linear interdependencies among multiple time series. VAR models generalize the univariate autoregression (AR) models. All the variables in a VAR are treated symmetrically; each variable has an equation explaining its evolution based on its own lags and the lags of all the other variables in the model. VAR modeling does not require expert knowledge, which previously had been used in structural models with simultaneous equations.
Sims advocated VAR models as providing a theory-free method to estimate economic relationships, thus being an alternative to the “incredible identification restrictions” in structural models.[1]. Sims was awarded the 2011 Nobel Prize in Economics for his work in applying VAR models to macroeconomic analysis.[2]
[Interesting, so I’ll leave it. But in general, read the instructions, stick to an elevator speech for Nikolov or Jelbring, or a falsification of my proof. Thanks, -w.]
I am enjoying the thought process here. Some aren’t paying attention to Willis’ constraints:
1. The perfectly smooth, perfectly round, single substance planet is receiving equal amounts of heat/energy uniformly from all directions.
2. The added surrounding atmosphere is perfectly transparent to the heat/energy sources.
In this scenario, it would logically seem that since the atmosphere by definition can have no effect, it is having no effect; the denseness of the atmosphere caused by gravity will not matter.
However, now replace that atmosphere with one of 100% of any other gas, also insuring that the parameters will not be such that the gas will cool or warm enough to change state. Now, the warmer surface of the planet will heat the portion of that atmosphere that touches it, and heat “rises” (moves away from the center of gravity) toward the upper levels of the atmosphere while the cooler gas replaces it and is being heated and it “rises”, etc. until it reaches equilibrium.
If I’ve got that correct, than here are my questions: If there was only a “ball” of that gas in that same theoretical position, what would the temperature of center of the gas be? Would it not be lower than the surface of the theoretical planet? If so, then with all the conduction and convection going on in the planet/gas configuration, wouldn’t the gas ultimately be a coolant for the planet? Wouldn’t gravity be the driving force causing the heat to be moved away from the surface of the planet by pulling the cooler, denser gas toward it?
In this regard, I have a serious doubt regarding “down welling” in this scenario, too. Even if the chosen 100% gas is CO2, wouldn’t warmer molecules always “rise” or move away from the surface? As has been pointed out many times, the radiation is “out welling” – moving out in all directions. Essentially, if all the molecules in a given area are “out welling” at essentially the same rate, wouldn’t they all move somewhat together, taking their heat/energy with them, “up” or away from the center of gravity?
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.
I suggest you can test both theories with data at the South Pole during the six months of night. There is no direct energy input from the sun. Water vapor is the least of any place on earth and the accumulation of snow is a measure of energy conservation. The air is thinner at that altitude. Energy is being delivered by the atmosphere and lost to space by radiation. These input and output rates can tell us if atmospheric CO2 has had any significant “greenhouse” effect.
Essentially, more mass equals more gravity which results in a hotheaded person, radiating fury at a crazier rate the denser he be. :p
I dont know the theories of N&Z but the physics in your example are quite easy and clear. An atmosphere will increase the temperature of the planet even if the atmosphere does not emit infrared. The reason is that the atmosphere will get heated by the ground by convective heat transfer. Because of this heating the air at the ground will raise up and create air circulation causing a redistribution of heat from hot parts of the planet to cold parts of the planet. In other words heat will be transfered from the ground to the atmosphere in hot places and heat will be transfered from the atmosphere to the ground in cold places. The result is that acording to the T^4 law the temperature has to be higher to emit the same amount of energy. All of this ofcause assumes that the planet is rotating. The confusion stems from the fact that there are more than one way that heat can be transfered or moved.
– Convective heat transfer only happens between a liquid/solid gas/solid og gas/liquid interface
– conductive heat transfer only happens inside solids
– radiation
– Mass transfer for eksample when air moves from one place to another carrying stored heat
– Phase transitions like evaporation and solidification.
In this case Willis has forgotten about the convective heat transfer. and the mass transfer modes of moving heat. If convective heat transfer and mass transfer does not happen Willis is right.
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.
jorgekafkazar says:
January 13, 2012 at 11:27 pm
“Is that short a tube accurate enough for the levels of energy and accuracy we’re dealing with?”
If I remember my light physics correctly, light energy is lost by destructive interference laterally during transmission through the atmosphere. I do not know what proportion is lost but the sky is blue because of the lateral dispersion. This dispersion to the atmosphere might the atmosphere a bit but it would decrease the energy reaching the surface, making it difficult to hold the planet up to a gas less black body radiation budget. It would not be fair.
Also, I know the discussion involves surface temperature but the numbers we have for Earth are NOT surface temps, they are from 5–6 feet above the surface; thus, atmosphere is being measured not the surface. Measuring the surface would be much too circumstantial regarding conditions, materials, etc. I am coming to an apples and oranges position, albeit reluctantly.
In science there is only one test that has any meaning. The ability to predict. The method that gives the best predictions is the best theory.
N&Z have found a means to predict the temperature of planets based on atmospheric density. Repeat their exercise with radiation and see if it gives a better result. Not just on one of two planets and moons, but all of them.
Because in the end, a theory that matches the data in one of two cases, but fails in other cases, is a failed theory. So far, the climate models which are based on the radiation theory have done a pretty poor job of forecasting temperatures since 2000. This suggests there is more to the story that GHG.
Willis
I admire your honesty and your knowledge. (perhaps a tiny bit less anger wouldn’t go amiss!)
II totally agree with your reasoning.
The only difficulty I have is with “bb radiation”:
a) it is said all matter radiates broadband according to its temperature
b) it is then said gases do not radiate in this manner but only radiate at discrete wavelengths (GGs at LWIR and O2 N2 in UV This is the reason why the sun does not heat the atmosphere little UV gets through to gnd level)
c) most people seem to have trouble with the concept of GHG free air not being able to cool / heat other than by conduction ( a N2 packet – uncontained – of gas in a vacuum would not cool – any containment would heat and then BB radiate to cool the gas by conduction).
Perhaps they also need to consider a roughened black anodised aluminium block radiating efficiently – change the surface – polish it to 100% reflectance and most would agree that radiation will be reduced. i.e. change its state and you change its level of radiation.
Can the same be said of a gas.
Does liquid nitrogen have a bb radiation? I would say yes.
Does changing to gas then change the only radiation to a few lines in UV? I am not sure but side with the possibility that non-GHGs do not have bb-radiation
Can anyone who can show proof that gasses to NOT have “BB-radiation” please?
scienceofdoom has promised to cover this!
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.
There, Willis… Is everything clear now?
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.
Planet without atmosphere warms to S-B temperature. Energy out = energy in. Everyone happy.
Wrap planet in an atmosphere (GHG free if you wish), atmosphere provides a insulation effect, ‘slowing’ the release of the out going energy, temperature of planet rises to a sufficient level that the original energy out figure is reached.
Planet plus atmosphere give same energy out = energy in but with the planets near surface warmer than before. Everyone happy.
In both cases the energy in and out are the same, no rules broken.
Specifying which heat transport mechanism is in use and by how much does not help the basic explanation.
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.
Nature is not in any way influenced by the logic of argument. What may seem completely rational and logical has been shown time and time again to be wrong. If your argument describes nature, then it will have predictive power. If there exists a single case where this prediction fails, this is evidence that the argument does not describe nature, simply coincidence.
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?
More blue box replies please… Thank you.
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 Eschenbach listed a book as a reference. More convenient would be online sites.
Years ago, I was searching the web trying to get at least a highschool science understanding of the greenhouse effect, as opposed to heuristic handwaving,. The firs numerical site I found was the late John Daly’s site: Here’s a good link describing the greenhouse effect.
http://www.john-daly.com/miniwarm.htm
From there, it was guest papers like this,
http://www.john-daly.com/artifact.htm,
other sites like this,
http://www.geo.utexas.edu/courses/387H/Lectures/chap2.pdf
and finally links to other sites, leading to “Climate Audit”, and finally to the promised land-
“Watts Up With That?”
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.
Michael Reed,
I believe you have made a profound point. Engineers such as myself struggle for years with expert help to understand these devilishly complex technical questions/issues. Without having gone through that, you must rely on someone who has. Find one you trust and ask him or her.
Failing that, I will answer. No, we are not. The earth has been far warmer and far cooler than now, with far higher, but not much lower, concentrations of CO2. There is no correlation between the two according to data from many sources. The “average temperature of the earth” is nearly impossible to ascertain, and we have only been recording temperature data in more than just a few places since 1851, and not accurately enough to determine whether changes mean anything. For example, climate scientists debate changes on the order of 0.01 degrees C, using data from weather thermometers accurate to +-1 degree C, obviously ridiculous. Despite this, most of them agree that the average temperature of the Earth probably has risen 0.7 degrees C since 1851! Does that seem like a lot? Not to me. Has it changed more than that and faster than that many times? Yes it has.
There, glad I could clear that up for you!
I haven’t had time to carefully read all the replies, but several comments and conclusions in the posts seem to forget one important fact.
Air cools as it rises.
Rising air is gaining gravitational potential energy and must be losing other energy. It does this by expanding and cooling. This is the physical reason behind the lapse rate. So even if we had a planet with a uniform temperature of 255 K at the surface, only the bottom layers of the atmosphere would warm to this temperature. Temperature in the the upper layers would drop off at approximately the lapse, so the “average temperature” of a transparent atmosphere will always be less than the surface temperature.
COROLLARY. The idea that “falling air will get heated by gravity as it falls” ignores the fact that gravity had equally cooled the air as it rose. If you added NEW air at the top (perhaps from a small comet hitting the earth), then this new air falling would have warming effect (at least temporarily).
**********************************
A second very minor point is that the energy balance must also include geothermal energy. On earth this is a minor effect (on the order of 1 W/m^2), so the energy emitted will be slightly larger than the energy absorbed. On the moon this would be an even smaller effect. On Jupiter, however, this is a significant effect, warming the “surface” well above the SB temperature. (http://en.wikipedia.org/wiki/Internal_heating#Gas_giants)
********************************
Finally, I want to reiterate that I agree with Willis and his overall conclusions.
I have to say, it’s pretty darn thrilling to see WUWT folks taking such an interest in thermodynamics and transport theory! There is perhaps no better subject than transport theory to unite mathematics, physics, engineering, biology, ecology, and economics. And conversely, an solid grasp of transport theory makes it far easier to appreciate these topics as aspects of a unified whole … which is perhaps why three of the greatest scientists of the 20th century were attracted to it:
(1) Albert Einstein for Brownian motion and black-body radiation,
(2) Paul Dirac for a (still largely classified) theory of U235 isotope transport in centrifuges, and
(3) John von Neumann for the computational theory of detonation waves and
boundary layer transport (H-bombs, aircraft, and missiles)
Regarding Alexander Feht’s dubious assertions, it is true that Boltzmann killed himself, and it is true too that Boltzmann faced opposition to his ideas. But opposition is very commonly encountered in science, and perhaps a more likely explanation is Boltzmann’s lifelong history of depression, worsened by grief over the unexpected death of his eldest son (from appendicitis).
On the other hand, perhaps it is well to reflect upon the celebrated opening lines of David Goodstein’s physics textbook States of Matter:
So if you should find yourself starting to feel a bit “down” reading this particular WUWT topic … then please take a break! 🙂
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
My roof stored negative energy last night. It was covered in frost. When the sun hit it in the morning, energy that would otherwise have heated the tiles was used up in melting the ice and evaporating the resulting wet surface.
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.
Not only integrating sphere, Michael, but also thermal IR sensors and cameras. One has to know the true emissivity in order to sense temperature accurately.
It is quite a lot more complicated, which is why in engineering we do two things to simplify. To avoid having to integrate emitted power throughout the entire volume of gas onto the point of interest, we resort to a “effect length” of path through the gas that depends on the geometry of the enclosure, which makes the problem quasi-one dimensional. For example, the effective length of path to one surface in an enclosure between infinite planes is 1.8 times the distance between the planes.
Second, we find the “emissivity” of the gas as a function of partial pressure of H2O and CO2 (the two common gases involved in IR) and temperature from a chart, or from a program that represents the chart. Problems in which there is a temperature gradient in the gas are more complex yet. Active gas in an enclosure is not a simple problem.
I agree quite generally with Willis on this post. One general comment I would make is about the common use of the term “radiation” as in radiation=sigma*T^4. What we actually calculate is emitted power; i.e. power (watts) emitted per unit area of surface into a hemisphere above that surface. Not keeping in mind the units of things leads to a lot of confusion.
Willis says he disagrees with this notion:
“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.”
Wayne says: “No Bill, if the air was ever warmer than the surface the air would transfer by conduction that energy from the air TO the surface, always warmer to cooler. It would not just accumulate. Eventually an equilibrium would be established.”
Peter Sorenson says: “Willis has forgotten about the convective heat transfer. and the mass transfer modes of moving heat.”
There is no planet that derives heat from a multitude of surrounding suns. [snip: My friend, it’s called a “thought experiment”. -w]
The argument that theory trumps observation is what has led so many astray. Here is a practical demonstration of a device that is theoretically impossible.
First, let’s clear up two separate uses of the term “lapse rate”. Willis refers to the dry adiabatic lapse rate. This is a decrease in temperature per height gain in a rising air parcel. It is a process — adiabatic decompression.
Second, the term “lapse rate” in the atmosphere is the general decline in temperature of the troposphere with altitude. It is the end result of a whole series of processes that contribute to a final temperature distribution — one of these processes is adiabatic sinking or lifting of air, so is radiant emission.
When we use the term specific heat, we are not speaking of heat, but rather how much heat is needed to raise the temperature of one kilogram of material one degree celsius.
Cp is a measure based one-kilogram mass of material. If you increase density by jamming more kilograms into a volume, the specific heat remains the same because it is per unit mass. The heat capacity per unit volume increases, but not the specific heat. So thinner air has less heat capacity, but not less specific heat.
Oh, and let’s not forget the ocean.
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?)
Willis is right, but they might quibble (though they didn’t think to make this suggestion) that clouds radiate at colder temperatures, so this effect goes in the right direction to balance the energy. However, the cloud-top distribution that is observed does not help to close the energy balance.
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.
The Love of AGW Theory “elevator speech”
Free enterprise capitalism and America for that matter are an evil that must be crushed through govcernment regulations on all factors of production and taxing productivity. Fear of AGW is what informs us because the ends justify the means.
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.
Let me see if I have this correct. An N2 O2 atmosphere without GHG does not cool by radiation.
Thus, without GHG, the earth’s surface would need to be warmer than it is now, to radiate the equivalent amount of energy to space as is currently radiated by the surface and atmosphere together.
Thus, the only effect that GHG can have on the surface is to cool the surface.
(atmosphere + surface) ^4 is greater than (surface) ^ 4
(atmosphere + surface) ^4 is equal to (hotter surface) ^ 4
Since we know that radiation in must equal radiation out, if N2 and O2 do not radiate, then the only conclusion that is possible is that GHG cools the surface.
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.
Badly done experiments can prove almost anything–thankfully here one of the participants at least tries to explain why the experiment does not debunk Newton. This thing works for the same reason that thrust deflectors on a jet engine slow the jet airplane. Newton rules!
“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.
Mathematical proof that GHG cools the surface of planet earth
In an atmosphere with GHG
total energy incoming from sun = net energy emitted to space by GHG atmosphere + net energy emitted to space by surface(1)
In an atmosphere without GHG (non radiating),
total energy incoming from sun = net energy emitted to space by surface(2)
Therefore this can be rewritten as:
net energy emitted to space by atmosphere + net energy emitted to space by surface(1) = net energy emitted to space by surface(2)
Which then becomes:
net energy emitted to space by GHG atmosphere = net energy emitted to space by surface(2) – net energy emitted to space by surface(1)
Since we know that “net energy emitted to space by GHG atmosphere” > 0
We can rewrite this as
net energy emitted to space by surface(2) – net energy emitted to space by surface(1) > 0
Thus
net energy emitted to space by surface(2) > net energy emitted to space by surface(1)
Since we know that net energy radiated to space is a function of temperature, we can then say:
Temperature surface(2) > Temperature surface(1)
QED
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.
Thanks, Willis, for another interesting post.
Edim says:
January 14, 2012 at 1:01 am
“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)?”
Leonard Weinstein’s comment (above) seems to be relevant to Edim’s question. I don’t claim expertise in this field, I’m still learning, and would welcome correction, but as I currently understand it this is what might happen.
1. The mass of the atmosphere would be aproximately doubled.
2. The newly added N2 would be quickly mixed with the existing atmospheric components, included the radiative gases.
3. The mean height of emission of out-going long-wave radiation (OLR) would be increased. By how much I don’t know, but I don’t think it would be doubled.
4. If the lapse rate remained the same the average surface temperature would rise. By how much would depend on the magnitude and sign of the feedback factor.
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.
As a chemical engineer, I support Willis’ conclusions completely. It’s nonsense that a GHG free atmosphere will affect the temperature. The field of climate science is full of such nonsense, and it doesn’t help the skeptics cause to unskeptically perpetuate their own.
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?
So, Willis. Did you choose the 9-12 micron range because it hits the water and CO2 main bands? Some other reason?
Guest Post by Willis Eschenbach
TO CONCLUDE: I’m interested in people who can either show that my proof is wrong
There is no free lunch. If the GHG atmosphere is radiating, then there must be a reduction in radiation somewhere else.
lateposter says: January 14, 2012 at 9:13 am
No you don´t understand the content of my E&E, 2003 paper correctly. Willis has been putting words in my mouth that I have never said and he refuses to adress what is written in my peer reviwed paper, since 8 years. There certainly are no “Elevator version” of my paper which is based on first principal physics. It means that what I have written is either true or false. There is nothing inbetween. After 8 years nobody has falsified it and Willis attempt here is subclass for a number of reasons.
See the reference given by Tallbloke here 3:35 PM “The Greenhouse Effect as a function of atmospheric mass” and get firsthand information. I certainly appreciate a number of comments in this thread where the authors can discriminate between an approximate model and to what degree its properties can be applied to any real planetary atmosphere. There is little or any use for Willis model in this respect but there is plenty of use with the model I have describe. The former cannot be verified in any planetary atmospheres. The one I describe can be verified by observational evidence in Venus, Titan, Jupiter, Saturn, Uranus, Neptun. Mars fails for a simple reason. Its atmosphere is not massiv enough. The earth´s atmosphere is in the middle between Mars and Venus and is especially tricky to handle. There are so many physical processes that are involved changing the static average tmperature rate from -9.8 K/km to about 6.5 K/km. Some poeple in this thread has notice the importance of atmospheric surface mass per unit area. This is the first and last comment I will do on this thread.
Thanks
Hans Jelbring
Thanks, Willis, for the nice post.
Bill Illis says:
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.
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:
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.
Willis Eschenbach and others have assumed that without water vapor, the lapse rate for a planet would be constant,
It wouldn’t. Lapse rate also depends on temperature. As the temperature cools with height, the
lapse rate drops
let atmospheric density = r., pressure= p, temperature = T, gas constant for dry air = R,
lapse rate = L.
T0 = ground temperature, p0= ground pressure, height = H
Then
L = (gr/RT)(dT/dp)
With constant density,, at current surface pressure, the lapse rate would b
:L = g/R = 3.42 C per kilometer. Such an atmosphere would have a specific finite height.
With constant temperature, the pressure would be proportional to the log of the pressure
height 2 – height 1 would be 29.3* ground temperature *( lnp1/lnp2)
With constant lapse rate
p = p0 ( 1 – (LH/T0))^(g/RL)
Needless to say, in the real world atmospheric density is not constant, nor does it drop off
exponentially with height- which would imply a constant temperature atmosphere, nor
is the lapse rate constant, It’s a messy average of those 3 ideal cases.
…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!
Let’s put this gravitational work in its proper perspective…
[SNIP: Let’s not. Lets stick to the topic of the thread. -w.]
ferd berple says:
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.)
And, what law of physics is this…and how does it pertain to anything being talked about?
Gina Becker says:
January 14, 2012 at 9:57 am
It’s nonsense that a GHG free atmosphere will affect the temperature.
Stand at sea level in an atmosphere free of GHG. Now stand at the top of a mountain in an atmosphere free of GHG. There will be an affect on temperature.
The problem comes in assuming that GHG warms the surface. In fact the opposite is true. GHG cools the surface, in the same way it cools that atmosphere, by radiating LWR to space that would otherwise remain trapped in a non-radiating atmosphere.
This effect is most noticeable in the upper atmosphere, where temperatures can reach 1500C in the absence of GHG cooling.
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.]
OK, I made a fool of myself with “Stefan-Boltzmann”.
My mistake.
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
Your proof is of course correct. Did you realize why Jelbring and N&Z-“theories” give quite nice values? The deeper reason is the lapse rate, the dry lapse rate given by g/c_p. There it is, the effect of gravity. The “theories” are equivalent to lapse rate calculation, but they miss the central point: Where to start with, what is the right height h?
The answer ist given by ghg-theory: it’s the height, where the ghg-concentration is optical thin enough, that IR-radiation is able to escape to space.
(Therefore I like the following explanation of GHG-theory more: Adding more GHGs will elevate the level, where radiation can escape to space. It’s colder there, so earth emits less energy than it receives. The atmosphere will warm, until it radiates in the elevated level the same energy as before.)
Another indirect proof:
Imagine a planet moving around a black hole or wandering through empty space without a star like the sun. According to Jelbring or N&Z this planet should have the same temperatur as the planet moving around the sun. Nonsense.
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.
There is no principle called “conservation of radiation”. There is conservation of energy and radiant energy is but a part contributor to that principle.
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).
wayne says:
January 14, 2012 at 12:33 am
Willis:
So your argument is that on a planet with a transparent GHG-free atmosphere, the surface is continually losing energy by conduction … riiiight, that’s the ticket …
Why is it that when a charming fellow like you make some idiotic statement that clearly violates conservation of energy, they feel they have to finish it off by insulting my understanding? Medica, cura te ipsum …
w.
Willis Eschenbach says:
January 14, 2012 at 12:32 am
So how do you not understand Huffman’s explanation?
Throw out unrealistic assumptions about blackbodies, greybodies, albedos, etc. and the complications surrounding them.
It’s simple recognition that the temperature profile of earth and venus are very close given similar pressures and considering their relative distances from the sun in spite of massive differences in concentrations of CO2. It’s natures results and natures experiment.
Can you explain why the temperature/pressure profiles are so close? Here’s the link.
http://theendofthemystery.blogspot.com/2010/11/venus-no-greenhouse-effect.html
Surely it’s a rather amazing coincidence if there is a greenhouse effect.
Convince me that the molten core of the earth has no effect on the temperature of the planet surface with or without an atmosphere or a solar source. [SNIP: Not on this thread, I won’t. -w]
Roger Clague says:
January 14, 2012 at 12:38 am
Crosspatch was wandering off to discuss the earth with an atmosphere of greenhouse gases. As I recall, I told you I would snip what I thought was off topic, not what you thought was off topic, lemme check … yeah, there was no mention of you deciding who was off topic.
Don’t like it? My apologies, you weren’t around to ask.
w.
PS—I note that you have not given us the elevator speech for your “theory of gravitational enhancement”. Until you rectify that egregious omission, why are you opening your mouth about your theory? I do love that your theory claims that you can’t have a GHG-free atmosphere, that’s a new one for me.
NoIdea says:
January 14, 2012 at 6:14 am
Excellent explanation NoIdea. 🙂
– Willis, – is your GHG-less atmos transparent? or just approximately so for gubmint work.
– There is mass in this atmosphere in the form of gas atoms that photons do collide with (and are absorbed).
– Beers Law T= I/I sub o (Transmissivity = incident photons/transmitted photons through a slab of air) which equals e^(-sigma l N); sigma is absortion cross-section of gas atoms/molecules; l is thickness of air and N = number of atoms/molecules in the path.
-N increases as the air pressure increases – greater excitation in the lower atmos
-Energy absorbed (and eventually re-emitted) E =Planck cons*c (speed of light)/lambda wavelenght of light (not just IR).
-Imagine an atmos pressure at the bottom that is near liquifaction to exaggerate the picture.
Stephen Wilde says:
January 14, 2012 at 10:19 am
Thus Oxygen and Nitrogen are involved despite being relatively non radiative.
Oxygen and Nitrogen participate fully in adding to the process of conduction
in its competition with radiation.
Exactly. In the absence of GHG, the atmosphere would not be able to lose energy to space. Any energy lost to the atmosphere from the surface would eventually be returned to the surface.
In contrast, with a GHG atmosphere, energy lost from the surface to the atmosphere can then be radiated to space by the atmosphere and need not be returned to the surface.
Thus, without a GHG atmosphere, S-B tells us that the surface of the planet must warm to radiate this excess energy, that is no longer being radiated away by the atmosphere.
ferd berple says:
>The argument that theory trumps observation is what has led so many
>astray. Here is a practical demonstration of a device that is theoretically impossible.
and
>Mathematical proof that GHG cools the surface of planet earth
Unfortunately, Fred, you don’t quite understand the theory involved in either case. The blow-your-own-sail is counter-intuitive to many people, but fully within the rules of newtonian mechanics. The greenhouse is also and counter-intuitive to many people, but it also follows the rules of physics.
Eric Barnes says:
January 14, 2012 at 10:53 am
Willis Eschenbach says:
January 14, 2012 at 12:32 am
So how do you not understand Huffman’s explanation?
Throw out unrealistic assumptions about blackbodies, greybodies, albedos, etc. and the complications surrounding them.
It’s simple recognition that the temperature profile of earth and venus are very close given similar pressures and considering their relative distances from the sun in spite of massive differences in concentrations of CO2. It’s natures results and natures experiment.
Can you explain why the temperature/pressure profiles are so close? Here’s the link.
http://theendofthemystery.blogspot.com/2010/11/venus-no-greenhouse-effect.html
Surely it’s a rather amazing coincidence if there is a greenhouse effect.
Not a coincidence at all if there is a maximum greenhouse effect. All the planets would warm up until they reached that maximum. If that maximum just happened to be determined by the mass and the gravitation of those planets then we would see exactly what Huffman sees. However, for the surface to warm above the SB calculations there must be an effective radiation altitude above that surface.
We don’t need to discard the GHE. It’s real, it just has limits that haven’t been discovered because of simplifications made to climate models.
Willis Eschenbach says:
January 14, 2012 at 10:50 am
So your argument is that on a planet with a transparent GHG-free atmosphere, the surface is continually losing energy by conduction … riiiight, that’s the ticket
I think you have this backwards. In a non GHG (non radiating) atmosphere, any heat lost by the surface to conduction must be returned to the surface – for example at the poles. In contrast, in a GHG atmosphere, heat lost by the surface to conduction can then be radiated to space by the GHG atmosphere.
Thus, the GHG atmosphere MUST result in a lower average surface temperature as compared to a non GHG atmosphere, due to the energy lost via atmospheric GHG radiation.
Crosspatch and others keep claiming that oxygen and nitrogen are greenhouse gases, for example saying:
crosspatch says:
January 14, 2012 at 12:39 am
I don’t know why, but some folks seem to think that all things radiate at all temperatures. They don’t.
Here’s the deal, Crosspatch and others. Nitrogen and Oxygen are diatomic molecules. Basically, they are transparent to IR, neither emitting nor absorbing infrared energy. They might radiate at high temperatures like in the sun, I don’t know.
But at the temperatures that we are talking about, all of the radiation is in the infrared, a frequency where oxygen and nitrogen neither emit nor absorb radiation.
Here’s the IPCC on the subject, emphasis mine:
So no, Crosspatch, the idea that you have that all things absorb and radiate in the IR range is simply not true. A non-GHG atmosphere will radiate only the most minuscule amount in the IR, an amount that is way, way, way below the 1 W/m2 levels we’re talking about. Sure, over the next billion years that would cool them … but in terms of our questions, they do not radiate in the IR.
w.
I believe Willis’ proof is not correct.
In a real world with a no-GHG atmosphere, the atmosphere still absorbs heat from the surface through conduction and convection. And the near-surface temperature of the atmosphere is not the same as the “skin” temperature of the solid or liquid surface.
If one adds more atmosphere, there will be more conduction/convection. The “skin” temperature will decrease and the skin will radiate less. The near surface gas temperature, however, will rise and the radiation from the atmosphere as a whole will increase, maintaining a total balance.
In simple terms, the sand on the beach will not burn your feet as much, but the air you are immersed in will be warmer and will be radiating more.
When we talk about the “surface” temperature, what are we talking about, the “skin” or the air? We should at least be clear about that, because the “skin” can get very, very hot. With radiation increasing as T^4, hot beach sand radiates a hell of a lot more than the same beach sand, irradiated in the same way by the same sun, but cooled by a brisk wind.
In short, none of the models I’ve ever seen is either complete or coherent. Which explains the confusion.
Well, to stupid me it seems unbelievable how many here seem not to understand the difference between energy and temperature. Thanks to the few voices in the wilderness who clearly do understand. (One thing I do seem to remember from my university days too many decades ago) When I got to Willis’ talk about temperature issues somehow conflicting with conservation of energy (or something to that effect) I just skipped to the comments.. And why, pray tell, should it be possible to definitively explain the physics of it all in an ‘elevator speech’ of a few lines? Who was it who said that simplicity can also be the essence of untruth?
Gabriel van den Bergh
@fred berple GHGs can only radiate into space long wave / infra red photons intercepted from the surface and stored in internal energy states. They cannot emit additional photons that they haven’t captured emerging initially from the surface of the planet.
AIUI The effect of GHGs is that they STORE energy in the vibrational energy states corresponding to the infra red radiation energies. This energy may be later released as heat. The rate of spontaneous emission has a reverse relationship with frequency, so the energy is retained for a relatively long time (minutes, hours).
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.
I don’t know why, but some folks seem to think that all things radiate at all temperatures. They don’t.
No one said it radiates at all temperatures. No one is even saying that all things radiate IR. What they”re saying is that everything radiates at SOME frequency. At least that’s my understanding… correct me if I’m wrong. U of Virginia seems to agree.
http://galileo.phys.virginia.edu/classes/252/black_body_radiation.html
Any body at any temperature above absolute zero will radiate to some extent, the intensity and frequency distribution of the radiation depending on the detailed structure of the body.
So simplifying the earth to only consider IR is a gross oversimplification. For example, the earth was also hit by UV rays. Some of the material in the earth will absorb those UV rays and increase the energy of the earth. Conduction within the earth will transfer some of that energy to other materials, which may have a different emissivity… say it emits in IR. So in that instance we have IR being generated from the surface that did not arrive as IR!
So, an atmosphere that aquires heat content from the surface of the earth (and it MUST, right? your atmosphere can’t be at absolute 0 or it’d be a solid) has the possibility of radiating that energy as microwaves, etc, etc. Reducing the heat content of the atmosphere and the surface.
To totally ignore all emissivity except IR seems a gross oversimplification.
Tim Folkerts says:
January 14, 2012 at 11:11 am
The greenhouse is also and counter-intuitive to many people, but it also follows the rules of physics.
No, you have it backwards.
Nature does not follow the rules of physics. Physics describes the actions of Nature, and the description is imperfect, due to the existence of the “unknown” which for all practical purposes is infinite in size.
I have shown a very simple mathematical demonstration of why the GHG theory does not describe nature. If you wish to refute this, show where the mathematics in in error. You cannot do this via rhetoric, you must do so via mathematics.
The gravitation theory of surface temperatures has demonstrated a predictive power across multiple examples. Something the radiative theory is yet to demonstrate.
“No one said it radiates at all temperatures. ”
Actually, all temperatures but absolute 0. Duh. 🙂
I thank Dr. Jelbring for his response, and I apologize if I misrepresented his paper. But my comments were based on reading it, not second-hand from Willis. I thought it was easy to understand, and I’m not claiming to have found any statement in it that wasn’t true, but the definition of greenhouse effect implied by the paper seems to be different from what other people mean by it.
I understand the greenhouse effect to be something that raises the effective radiation height, which together with a relatively constant lapse rate, results in a higher surface temperature, as explained by Leonard Weinstein.
Dr. Jelbring defines the greenhouse effect quite clearly as “The average global surface temperature minus the average infrared black body radiation temperature, as observed from space”. But this definition cannot be applied to his model, because it “neither receives solar radiation nor emits infrared radiation into space” and the GE “is independent of the absolute average temperature of the model atmosphere”. In it’s place, he identifies the GE with the lapse-rate-induced temperature difference (“the temperature difference (GE) between the surfaces”), dropping the all-important black body radiation temperature reference point.
Richard M says:
January 14, 2012 at 11:11 am
Not a coincidence at all if there is a maximum greenhouse effect.
Convenient explanation.
So we’ve maxed out at 390ppm CO2 and our current level of water vapor/methane?
Watch how far you back up. The cliff of never ending rationalization is near.
Eric Worrall says:
January 14, 2012 at 1:57 am
Nope. If you include the area of the atmosphere in your calculation, the theoretical S-B radiation will increase as well. Apples to apples.
w.
It just occurred to me, when Hansen said..
http://wattsupwiththat.com/2011/12/20/hansens-arrested-development/#more-53430
The precision achieved by the most advanced generation of radiation budget satellites is indicated by the planetary energy imbalance measured by the ongoing CERES (Clouds and the Earth’s Radiant Energy System) instrument (Loeb et al., 2009),, which finds a measured 5-year-mean imbalance of 6.5 W/m2 (Loeb et al., 2009). Because this result is implausible, instrumentation calibration factors were introduced to reduce the imbalance to the imbalance suggested by climate models, 0.85 W/m2 (Loeb et al., 2009).
Was he talking only about the IR portion of the spectrum?
http://en.wikipedia.org/wiki/Clouds_and_the_Earth's_Radiant_Energy_System
Each CERES instrument is a radiometer which has three channels – a shortwave channel to measure reflected sunlight in 0.3 – 5 µm region, a channel to measure Earth-emitted thermal radiation in the 8-12 µm “window” region, and a total channel to measure entire spectrum of outgoing Earth’s radiation.
If so, conversion of other wavelengths into emitted IR might account for some of that.
“The problem comes in assuming that GHG warms the surface. In fact the opposite is true. GHG cools the surface, in the same way it cools that atmosphere, by radiating LWR to space that would otherwise remain trapped in a non-radiating atmosphere.”
The oposite is often true in life. But I digress, I agree with this. The question is, how strong is the effect. Probably not very strong.
Willis:
Crosspatch and others keep claiming that oxygen and nitrogen are greenhouse gases, for example saying:
crosspatch says:
January 14, 2012 at 12:39 am
“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.
I don’t know why, but some folks seem to think that all things radiate at all temperatures. They don’t.
——————————————————————————–
So is only IR relevant? Are we saying that a substance transparent to IR but having heated up through energy gain by conduction or by compression cannot cool down by any mechanism other than (reverse) conduction or expansion? No radiation? So it will retain its heat indefinitely if none of these options apply? Or are we saying it cannot gain energy via conduction? Which is it, or am I missing something? Crosspatch makes more sense to me… sorry.
Gabriel van den Bergh
kcrucible says:
January 14, 2012 at 5:27 am
[NOT SO. Repeat after me, “GHG-free atmosphere”. The surface is the only thing that can radiate. w.]
You keep saying that, but it’s BS. Being “transparent” to IR just means that it can’t absorb energy via RADIATION. That does not mean that it can’t absorb energy by CONDUCTION. And ANY mass that has a higher energy than the stable state will then emit energy.
No it won’t because being transparent means that it has an absorptivity of 0 and by Kirchoff’s Law an emissivity of 0. Fundamental misunderstanding of the physics of gases.
Fred says
>The argument that theory trumps observation is what has led
>so many astray. Here is a practical demonstration of a device
>that is theoretically impossible.
And
>Thus, the GHG atmosphere MUST result in a lower average surface
>temperature as compared to a non GHG atmosphere, due to the
>energy lost via atmospheric GHG radiation.
Unfortunately, Fred, you are wrong on both counts. The blow-your-own-sail is perfectly within the laws of newtonian mechanics. The greenhouse-effect-warms-the-earth is perfectly within the laws of thermodynamics and radiation.
Interesting analysis Willis, but I admit a problem I have with it is that if a GHG atmosphere cannot radiate heat, than how can the surface of the blackbody do so, since it is also non GHG? Also, are conduction and convection limited to an atmosphere or do they also play a role in the surface (and below) of the planetoid? It seems to me these are salient points not addressed by your post.
There are mind-sets here which are almost impossible to overcome. I have limited my own mindset to the following:
Gravity compression of atmos is continuous process, not a one time batch compression. Conduction then convection ensure this continuity.
All gases when energized by conduction, above ambient, will radiate energy. Convection moves all heated gases, to locales, where it is above ambient. GHG or non-GHG matters not a twit. As long as it is matter… it matters. Poor radiators require higher delta T to transmit the same E as efficient radiators. This higher delta T is found at altitude.
Thermal energy conducted from ground (surface) to atmos is intercepted future radiant heat. Conservation of energy is maintained, as surface IR rate decreases due to conducted/convected heat loss.
Pressure induced lapse rate does seem to set the limits or mixture of radiative/conduction/convection rates… according to my present mind-set. That is all…as you were. GK
I’ve closed the other two threads on this subject since they were getting a bit ragged and Shore-worn, and directed everyone here to this thread.
On the wisdom or otherwise of an “elevator speech”:
Ok, I refreshed my memory. From the foreword of Aldous Huxley’s Brave new world: This is what was lurking in my mind:
“The soul of wit may become the very body of untruth. However elegant and memorable, brevity can never, in the nature of things, do justice to all the facts of a complex situation. On such a theme one can be brief only by omission and simplification. Omission and simplification help us to understand — but help us, in many cases, to understand the wrong thing; for our comprehension may be only of the abbreviator’s neatly formulated notions, not of the vast, ramifying reality from which these notions have been so arbitrarily abstracted.”
Gabriel van den Bergh
Roy Spencer says: January 14, 2012 at 4:09 am
As I have discussed on my blog, the observed temperature lapse rate of the atmosphere only describes how temperature CHANGES with height *IF* the atmosphere is convecting. It says nothing about what the temperature will be, in an absolute sense, which is an energy budget issue. If the atmosphere cannot absorb/emit IR, it would become isothermal, and all convection would cease.
I hate to argue against authority, but an isothermal atmosphere is unstable and will not remain that way. It will convect until it reaches the adiabatic profile, only then will convection cease.
N&z predicts only how a temperature will vary from the starting grey-body temperature, not the initial temperature itself.
FTA: “The Stefan-Boltzmann equation specifies how much radiation is emitted at a given temperature.”
Only for a blackbody in equilibrium. The corrected statement is
There are many loopholes in that description which might allow non-GHG heating to be physically realizable. I discuss some of these here. Your “QED” is not, in fact, demonstrative.
Willis,
I have stated the cause of the greenhouse effect in basic terms in a previous reply. The issue I want to discuss is your claim that if the amount of greenhouse gases was constant, but non greenhouse gases (O2 and N2) increased, there would be no change in ground level temperature. That is incorrect. Increasing the mass of the atmosphere not only increases surface pressure (linearly by the increase in mass), but also results in greater thickness (not a linear process). The mechanism for increase in greenhouse heating is simply that the gases would be mixed at all altitudes, so the average location of outgoing radiation would be increased some due to the greater thickness of the more massive atmosphere. The increase would be a nonlinear effect, and doubling mass of non-greenhouse gases would only increase temperature slightly for Earth, but it would definitely increase. It takes both greenhouse gases and the lapse effect to heat above a non-greenhouse level, but it is the effective average altitude that locks the temperature on the lapse rate curve. The effective lapse rate is not density dependent in the Troposphere until near the Tropopause, and for Earth, not temperature dependent.
Willis: “So your argument is that on a planet with a transparent GHG-free atmosphere, the surface is continually losing energy by conduction … riiiight, that’s the ticket”
According to NASA, Trenberth, and every global energy budget I have seen thats the case. Its somewhere in the range of a 100 watts global 24/7 average.
[SNIP: I’ll say it real slow. Traaaanspaareeent GHG-freee aaaatmooospheeereeee. NASA, Trenberth, and the energy budgets are about non-transparent atmospheres containing GHGs. The rest of your post is about that, and hence way off topic. -w.]
@ C Karst:
Love your mind-set…
Gabriel van den Bergh
“”””” Alexander Feht says:
January 14, 2012 at 12:55 am
Why everybody here imitates Mr. Eschenbach, using hyphen in “Stefan-Boltzmann temperature”, “Ste