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 …
“or we can explain how a nitrogen atmosphere would actually produce the difference in emission btw the surface and the planet as a whole.”
By storing solar energy in kinetic form (originally acquired by conduction from the surface) and then engaging in a dynamic conductive energy interchange with the surface.
So 240Wm2 comes to the surface from the sun and the surface radiates out 240W/m2 to space to achieve radiative balance.
Meanwhile the surface conducts 150W/m2 to the atmosphere and receives the same in return to achieve balance in the conductive energy exchange.
So the surface actually receives 240 from the sun + 150 from the atmosphere = 390
And radiates 240 to space plus conducting 150 to the atmosphere = 390
So there we have the answer and all in a non GHG environment.
Bill Hunter says:
January 16, 2012 at 7:21 am
Capo says:
January 16, 2012 at 3:13 am
“Tallbloke:
“No Willis, before we can move on to a discussion of the science, you need to acknowledge that Hans Jelbring defined his model planet as one which does not radiate to space,…”
That means that Jelbrings model is not “based on first principles of physics” in contradiction to what Jelbring says. Every body with T>0 radiates, so where’s the sense in this assumption?
If this is one of the assumptions, the conclusion would not belong to real, but a phantasy world.”
Jelbring’s model is nonsense which bears no relationship to reality of any kind.
His model involves a planet surrounded by an atmosphere which is in turn contained by a non-transparent shell at a density altitude of 0.1atm.
Neither the shell nor the planet is allowed to radiate, J seems to believe that this means the shell is black. Also the shell and planet surface have negligible thermal mass.
The atmosphere is heated by the planet by conduction and convection and so achieves the dry lapse rate between the planet and the shell. (Presumably the planet has an internal source of heat).
He defines this lapse rate as the ‘Greenhouse effect’ and because this is dependent on g therefore the real and totally unrelated Greenhouse effect must be too! The guy is completely out to lunch, he believes that no physical laws are violated in the construction of this model!
I was going to add a comment here that given the possibility that the atmosphere moves to an equilibrium state faster than the components of it change, it can be viewed as being in a quasistatic state. There are arguments that it is always in a state of non-equlibrium but I think that is simplistic. Bejan argues that it is self-regulating, always on the verge of being chaotic, because there is water in the atmosphere. My view is it is always self-stabilising to the point that it is quasistatic.
But, an important point was raised (or missed) when steveta_uk says:
January 16, 2012 at 9:54 am
>“The GHG-free atmosphere that does not insulate does not exist because it would also have to have no ability to conduct heat.”
>Conduct to where? If this is a non-radiating (or neglibably radiating to be picky) gas, then being conductive is irrelevant, as the is nowhere for the heat to be conducted to. Above is free space, non-conductive, below is a radiating surface.
This misses what I perhaps could have emphasized more: just because a gas ignores passing IR radiation does not mean it cannot be heated by conduction, and ALSO it does not mean it will not emit photons (which was called ‘negligably radiating’). In other words, a planet with no IR absorbing gases (by definition, all are non-GHG’s), still emits IR from those gases and energy at other wavelengths. You cannot find a gas that will not radiate any energy at all at any frequency no matter how high the temperature. Thus GHG’s have to be defined as those which do not absorb IR.
At some stage of excitement (input of energy) all gases will emit energy by radiation in some form.
As a simple example, take a polished silver globe and heat it. In an inert atmosphere it will not oxidise and the colour will remain the same; the emissivity remains pretty constant too. As the temperature rises, the wavelength range of emissions changes until the thing is glowing bright white at visible frequencies. IR is not the only way to emit energy. IR is not a ‘special kind of radiation’ it is just an arbitrary frequency range, a portion of the whole spectrum. A GHG-free atmosphere will still emit IR and other frequencies from the molecules in the atmosphere if it is first warmed by conduction from the heated black surface. Because there is some value of insulation provided by all gases, there being no superconducting room temperature gases, the black surface of our mental picture planet will heat the lower atmosphere. That heat will accumulate until either the temperature rise of the surface is hot enough to vent through IR alone or the system goes into radiative equlibrium with the atmosphere serving as a portion of whole radiative source. The latter is the only possible (real) solution.
Part of the problem for many contributors is confusing heat with temperature. The black body surface does not increase immediately to ‘full temperature” until the conductive, non-GHG atmosphere has been heated first. By then, the atmosphere has started radiating energy in all directions, just like GHG’s, some of it IR. To repeat, just because a gas does not absorb IR radiation does not mean it will not emit IR and other radiation.
Stephen Wilde says:
January 15, 2012 at 7:29 pm
Willis, just seen your comments which suggest more clarity needed on my part so here goes again:
1) Willis knows that his non GHG atmosphere will produce a dry adiabatic lapse rate with the warmest temperature at the surface.I am assuming some movement via convection to achieve it.
2) The warmth at the surface is NOT due to gravitational compression ( although a tiny fraction of it would be) but gravity IS responsible for placing the maximum density of non GHG molecules at the base of the atmospheric column.
3) That maximimum density causes the greatest number of molecular collisions to occur just above, or in contact with, the surface.
4) Such collisions transfer energy between themselves by conduction and not radiation. The surface converts incoming solar shortwave radiative energy into kinetic energy and the non GHG gases in contact with or in close proximity to the surface retain that kinetic energy by exchanging the energy via conduction between themselves and between themselves and the surface until it can be released upward by the surface as outgoing longwave IR.
No you have this wrong, the gas molecules transfer energy both to and from the surface by collisions, at thermodynamic equilibrium the net transfer is 0 and the surface temperature is constant as is the radiational exchange with space (equal to the radiation in the absence of the atmosphere).
5) It is that delay that allows the surface temperature to rise as energy accumulates within the system and most particularly at or just above the surface.
Such a delay is the time required to reach equilibrium.
6) The greater the density of the non GHG atmosphere, the more molecular collisions occur, the longer the delay and the higher the equilibrium temperature must become.
More collisions occur transferring energy in both directions, as we know for a gas obeying the ideal gas laws the thermal conductivity of gases is independent of pressure!
The increased density does NOT slow down the rate of conduction. Instead it increases the proportion of fast moving radiation that is retained for longer as slower moving conduction for an average net reduction in energy flow through the system.
This is frankly gobbledygook, and bears no resemblance to any physics I am aware of!
While we’re working on our elevator pitches, I would love to see one that describes the step-by-step linkages of how the atmosphere contributes 33C to the Earth’s surface average temperature. Let’s not just say blocked, trapped and/or stored. Blocked by what? How? Stored by what? How? Stored by what? How?
This thread reminds me of the “thought experiment” in which you give a group of monkeys some typewriters, paper, and infinite time…. eventually one of them types something meaningful.
Snipping the chaff makes 800+ posts a lot easier to wade through.
Some people here need to take a banana break.
Stephen Wilde says:
January 16, 2012 at 11:22 am
No, you didn’t make an error of attribution. You made the error of not quoting what I was supposed to have said. Had you done so, this would never have been an issue. I would have followed up the quote, and notified you politely that it wasn’t me, it was someone else.
But nooooo, complying with my request that you quote me is beneath a brilliant scientific mind like yours. The fact that I asked you to quote me specifically to avoid this kind of misunderstanding never crosses your mind.
Stephen, I’m sick of people not quoting me.
Your not quoting me in this particular instance is not an “error”. An error is spilling milk. We all do that.
Refusing to quote me after many, many polite requests (with reasons for the request) that you and others quote my words is a deliberate action. Not only that, it is a deliberate action that led directly to your oh-so-innocent “error”.
So I am overjoyed that you will no longer be misrepresenting my words, but rather the words of others, by refusing to quote them. The only thing that would make me happier is if you would take your scientific misunderstandings over to Tallbloke’s Talkshop, and leave behind a blissful empty space to be filled by someone more responsive to polite requests to quote my words in order to avoid misunderstandings.
w.
anna v says:
January 15, 2012 at 8:45 pm
Willis Eschenbach says:
January 15, 2012 at 11:13 am
There is no matter that does not radiate electromagnetically when in bulk.
The radiation may be small, in the low part of the electromagnetic spectrum not measurable easily, but it is there.
One has to realize that all, ALL , observable interactions of matter that affect every day temperatures are finally, at the last contact, electromagnetic. Electromagnetic means photons as a bottom line.
Argon has an emission spectrum too.
Yes indeed it does, an electronic transition, you apparently didn’t read your source carefully Anna, the spectrum is a discharge spectrum which required the passage of an electric current through the Argon. In a planetary atmosphere this would require a permanent electrical discharge through the atmosphere, there is no absorption of visible or IR light between those energy levels in the atmosphere because the excited electronic states are not populated in that case.
Crispin in Waterloo says:
January 16, 2012 at 12:10 pm
To repeat, just because a gas does not absorb IR radiation does not mean it will not emit IR and other radiation.
Repetition of a fallacy doesn’t make it true, the Physical Law that contradicts your statement is known as Kirchoff’s law. Emissivity at a wavelength is equal to the absorptivity at that wavelength.
“Your not quoting me in this particular instance is not an “error”. An error is spilling milk. We all do that.”
If you check my earlier contributions you will see that I always (or almost always) complied with your request to be quoted.
That was the first time that I can recall when I failed to do so.
Your behaviour is unacceptable.
Stephen Wilde says:
January 16, 2012 at 12:06 pm
“So 240Wm2 comes to the surface from the sun and the surface radiates out 240W/m2 to space to achieve radiative balance.
Meanwhile the surface conducts 150W/m2 to the atmosphere and receives the same in return to achieve balance in the conductive energy exchange.
So the surface actually receives 240 from the sun + 150 from the atmosphere = 390
And radiates 240 to space plus conducting 150 to the atmosphere = 390″
My first question here is if the surface receives a total of 390W/m2, how and why does it only emit only 240 to space? IOW, how do you know that a nitrogen atmosphere will donate the 150W/m2 to the surface? How do you calculate that amount to be 150W/m2?
Secondly, does your answer change at all if we assume that their are some GH gases in the atmosphere?
Cheers, 🙂
Phil. says:
January 16, 2012 at 12:06 pm
“Jelbring’s model is nonsense which bears no relationship to reality of any kind.
His model involves a planet surrounded by an atmosphere which is in turn contained by a non-transparent shell at a density altitude of 0.1atm.
Neither the shell nor the planet is allowed to radiate, J seems to believe that this means the shell is black. Also the shell and planet surface have negligible thermal mass.
The atmosphere is heated by the planet by conduction and convection and so achieves the dry lapse rate between the planet and the shell. (Presumably the planet has an internal source of heat).
He defines this lapse rate as the ‘Greenhouse effect’ and because this is dependent on g therefore the real and totally unrelated Greenhouse effect must be too! The guy is completely out to lunch, he believes that no physical laws are violated in the construction of this model!”
I guess it is correct he believes no physical laws are violated. Couldn’t the internal source of heat be of the sort that heats the gas giants before they ignite from getting too big and therefore too hot? Dr Brown here described such a process if I read him right.
Seems off the top to be related to the argument about whether the atmosphere would be isothermal or isentropic. Clearly convection would cease once it became isentropic at that point you would have no conduction because the kinetic energy of every molecule would be the same. So you are kind of stuck with a temperature gradient that doesn’t conduct. Kind of a unique property of gases and a mushy concept of temperature.
I guess the only way to make Jelbring to go away is really energetic arm waving so as to avoid headaches.
Stephen Wilde says:
Have you never heard of conduction ?
This thread is a total waste of my time.
Stephen, the gas in the compressor, the compressor wall (a metal) is a great conductor, and the gas outside the compressor all conduct. I never said energy was exchanged ONLY by radiative mechanisms. There is no reason to throw a hissy fit.
Stephen Wilde says:
January 16, 2012 at 12:51 pm
Stephen, first, yes, many times you have quoted me, you are correct about that.
But by now, you must have realized that if you are going to claim as in this instance that I agree with some wacky position of yours, which in this instance I definitely do not, that you damn well better point out exactly when and where I am agreeing with you or supporting your position.
The problem here is that you claimed, without doing your homework, that I’m on your side. The truth is, your statements are so far from accepted physics as to be hysterical. Your attempt to school Robert Brown, a PhD who teaches physics for a living, was priceless, watching you back and fill to try to prop up your nonsense. I’m not on your side, Stephen, I think you are a royal prat who has no idea that real scientists are rendered speechlessly hysterical by the unimaginable depth of your misunderstanding of physics.
So when you claim I am on your side, that I agree with you, and you do it without any attempt at citation or quotation, yes, Stephen, I will jump all over you with hobnailed boots, and ignore your subsequent whines and complaints about my doing it. Not acceptable in my book in any sense.
w.
shawnhet says:
January 16, 2012 at 11:13 am
“My question is based on what we can observe (ie that the surface emits on average ~390W/m2 while the planet as a whole emits ~240W/m2). “
We do not, in fact, observe that at all. We observe temperature at the surface (and, I haven’t even pointed out that, that temperature is actually not of the surface, but of the air a little above the surface). The 390 W/m^2 figure is a derived quantity from SB which, as I have been explaining over and over and over and over and over and over and over and over, is not dispositive.
“some wacky position of yours”
Such as the equilibrium between surface and atmosphere being dynamic ?
The more wacky proposal is that it is not dynamic such that once equilibrium is reached there is no further energy exchange. No net exchange maybe but no exchange at all ? Hardly.
The thing is that you depend on it being non dynamic for your proposition to hold. If it is non dynamic then the conductive part of the energy exchange can be ignored, the numbers no longer balance and you can claim that a non GHG atmosphere doesn’t have a warming effect similar to the radiative greenhouse effect.
If it is indeed dynamic then the numbers do balance and your proposition fails. No wonder I make you emotional.
As regards Robert Brown I have no problem with him schooling me. The issue there was my inability to match his terminology. As an experienced professional his use of terms is highly specialised such that my words in a more colloquial form were not adequate to get my meaning across.
In the end it didn’t matter because it turned out that the issues he focused on were not directly relevant to the wider scenario.Orbital mechanics is not a critical component of climate science.
JimOfCP says:
January 16, 2012 at 1:11 pm
Sorry, Jim. It was directed at Willis rather than you.
Crispin in Waterloo says:
January 16, 2012 at 12:10 pm
“To repeat, just because a gas does not absorb IR radiation does not mean it will not emit IR and other radiation.”
You should also add that higher frequency emissions radiate far greater energy per photon. An ultraviolet photon carries three orders of magnitude more energy than an IR photon.
“An ultraviolet photon carries three orders of magnitude more energy than an IR photon.”
And, on that note, here.
And, so, stream of consciousness here, we must consider that Willis’ fictitious planet, which he has artificially constrained from normal dissipative mechanisms, is likely roiled by lightening storms, which puts a real kink into all the hypotheticals.
“IOW, how do you know that a nitrogen atmosphere will donate the 150W/m2 to the surface? How do you calculate that amount to be 150W/m2?”
I was setting up an example that fits Earthly figures just to show that it is possible.
Also Willis’s model assumed equilibrium so it has to be a dynamic exchange between surface and atmosphere otherwise a disequilibrium would be introduced. It would not then be possible to account for the difference between energy in and the temperature of the surface (which is the situation Willis would prefer because it suits his proposition).
In my view for an equilibrium situation radiative in must balance radiative out and conductive up must balance conductive down with no leakage either way.
All that must follow from basic physics so it beats me why Willis thinks anything I’ve proposed violates accepted physics.
“Secondly, does your answer change at all if we assume that their are some GH gases in the atmosphere?”
Yes it does because GHGs allow radiation out of the atmosphere which Willis’s model does not. Whether the net effect of GHGs is cooling or warming is contentious in some quarters. For reasons I have stated elsewhere I think the effect is neutral but they do introduce a change in the rate of energy flow through the system which does have a minor climate consequence.
…lightning…
“The 390 W/m^2 figure is a derived quantity from SB which, as I have been explaining over and over and over and over and over and over and over and over, is not dispositive”
Yes, that is how I understood it.
In reality the figures for the radiative and conductive energy transfers in a non GHG model could be different from the ones I used but they would have to balance in the way I described.
Bart:”We do not, in fact, observe that at all. We observe temperature at the surface (and, I haven’t even pointed out that, that temperature is actually not of the surface, but of the air a little above the surface). The 390 W/m^2 figure is a derived quantity from SB which, as I have been explaining over and over and over and over and over and over and over and over, is not dispositive.”
Ok, let’s unpack this a bit. Is it your contention that an infrared camera (ie a camera that forms an image using infrared radiation) will show the same picture of a balloon at the surface(after cooling to ambient) temperature as of that same balloon will at a height of 3km?
Cheers, 🙂
Bart says:
January 16, 2012 at 2:00 pm
…lightning…
Possible 🙂
More likely a miniscule shift in the surface pressure distribution moving the permanent climate zones latitudinally by a mile or so. But don’t get me started on all that or Willis will shout at me again.