UPDATE: LGF fans, you may want to look at this post which is an introduction to a technical response to G&T and perhaps this non technical post to get an understanding of the level of Dr. Gerlich's poor understanding of thermodynamics. Those of you who can read German might want to dip into this 117 page discussion of the, what, 117 page? G&T paper.
You can find any number of very long and confused discussions about the greenhouse effect and the second law of thermodynamics including G&T. The simplest explanation of why they are buncum was provided in Rabett Run's comments by one Flavius Collium who followed Eli in pointing out that the greenhouse effect does not require that the colder atmosphere heat the warmer earth, but
I'd summarize it that the greenhouse gases "hinder the cooling of earth's surface".and Eli later provided a simple experiment that demonstrates how an intermediate layer can hinder the cooling of a hotter one radiating to a cold exterior (e.g. just as the earth radiates IR energy through the intermediate atmosphere to cold space.
Same if you use a resistor to heat a less insulated object vs a more insulated one - the insulation in both cases will always be colder than the object but the better insulated one will reach a warmer steady state.
Merry Christmas, that's enough reading for a few days.
------------------------------------
As Eli has mentioned, dotearth had a rather long (over 1000 comments, and some of them quite long) thread about this and that, one part of which was an extended exchange about Gerlich and Tscheuschner's arXiv manuscript. Rabett Labs has excerpted the substantive comments on G&T from that thread, excised some of the nasties, but left the content untouched. Some editorial judgment by the bunnies as to what was included and not. Pay particular attention to Arthur Smith's comments, especially the last one,
What you are still missing here is that no matter what model you use, when you have no atmosphere, you will end up with a global average temperature of 255 K or less. There is no atmosphere-free model of Earth, given its observed albedo and surface emissivity values and solar irradiance, that can possibly produce a higher temperature, under steady-state conditions.This is a VERY long post, one of the reasons Eli wants to go to Wordpress.
The fundamental reason for this is that, without an atmosphere, the absorbed radiation from the sun all reaches the surface of the planet, and the emitted thermal radiation from the surface all reaches space. If the planet is not in the process of warming up or cooling down, those two radiated energies, on average integrated over the planetary surface, must be equal.
So, given the Stefan-Boltzmann law (with whatever tweaks for emissivity are legitimate), the average value of the fourth power of the temperature across this atmosphere-free planet is fixed, if incoming solar radiation is fixed. The fourth root of that average value is the effective temperature, 255 K. And G&T pointed out that that effective temperature is always greater than the actual average temperature of the planet.
This inequality condition is exactly what G&T are showing with their discussion of different kinds of averages in section 3.7. But the logical conclusion seems to be one you three have missed: the Earth’s surface is too hot, compared to any comparable model without an atmosphere. By, not coincidentally, at least 33 degrees C.
If G&T had proved otherwise, they would have shown a model with a higher average temperature than 255 K. To the contrary, the only example they actually calculated had an average temperature far lower. That is only to be expected.
In fact you can create physically realistic model atmosphere-free Earths that have average temperatures ranging anywhere from as close to absolute zero as you want (a planet with zero temperature everywhere except in one spot) all the way up to 255 K (a planet with near-uniform temperatures) for the given average incoming absorbed solar energy. All you have to do is tweak the distribution of incoming energy across the planet; fiddling with heat capacity and rotation rates or thermal conductivity or covering the planet with a material with an appropriately tuned phase transition can also do it.
But there is NO such model that can produce an average temperature higher than 255 K. Given that Earth’s average is observed at 288 K, there is a fundamental discrepancy. That discrepancy is irrefutable proof of the atmospheric greenhouse effect. G&T, if they have made any contribution to understanding here, have only made that assertion more mathematically sound. Too bad they didn’t recognize what their own equations were telling them.
And here is the rest of it thanks to Cymraeg llygoden for teaching an old Rabett a new trick.
#111 January 25th, 2008 12:56 am Raypierre kicks it off:
Dear Mr. Morano,
You can obfuscate all you want, but you can’t hide from the fact that we have been going at this for nearly two weeks now and none of the skeptics we have discussed so far have established a credible publication record for the ideas that qualify them as skeptics in your eyes. Whatever these ideas are, they evidently can’t stand up to the same kind of scrutiny that the ideas in the IPCC report have been subjected to.
Today I’m in a good mood, so I’ll give you a twofer: Gerhard Gerlich and Ralf D. Tscheuschner . Neither of these physicists has produced a single peer-reviewed paper bearing on any aspect of climate science, or even on the radiative physics underpinning climate science. The two links you provide in fact point to the same paper. What you seem to be unaware of is that this paper has not been published in any journal. It appears only in the unreviewed ArXiv repository of manuscripts. This repository has no screening whatsoever as to the the content of the papers posted. Indeed, a look at the paper by anybody who has even a nodding acquaintance with radiation physics shows why they wouldn’t dare subject it to peer review. About 40 pages of this 90 page opus is in fact devoted to discussing the well-known flaws in the glass-greenhouse analogy sometimes used in simplified explanations of the phenomenon. These flaws have no bearing whatever on the manner in which the greenhouse effect is actually computed in climate models. The rest of the paper is simply bad physics; in fact, if they were right, not only would there be no anthropogenic greenhouse effect, there would be no greenhouse effect at all! They’ve proved too much! The Earth would be a solid ball of ice, and Venus would be 400 degrees colder than it is. And, as an aside, infrared weather satellites wouldn’t work either.
Since the work was never published, it of course has never been discussed in the peer reviewed literature. The obvious flaws in the paper cannot be discussed easily in a comment box, but for a good general guide to the junk physics in this paper I refer the reader to Eli Rabett’s discussion at:
http://www.inblogs.net/rabett/2007_10_01_archive.html
Eli also provides links to other discussions of the paper. But if you don’t believe these discussions, or can’t follow them, just think of this: If Gerlich and Tscheuschner were right, they’d publish their ideas in a peer-reviewed journal. They have every reason to. They’d become instantly famous, and no doubt win the Nobel Prize in physics for such a revolutionary overturning of everything known about energy balance of planets (and stars, too, for that matter).
— Posted by Raymond T. Pierrehumbert
180. January 25th, 2008 7:47 pm Gerhard Kramm enters stage left:
Dear Mr. Pierrehumbert,
There are a lot of reasons not to try to publish articles like those of Gerlich and Tscheuschner (2007) in peer-reviewed journals. First, the article of Gerlich and Tscheuschner is, by far, too long for typical scientific journals. Second, what does “peer-reviewed ” mean? It means nothing more that someone familiar with similar scientific stuff reviewed the manuscript to guarantee that publication standards of the respective journal are considered, to prevent plagiarism and publishing of highly erroneous material etc. Believe it or not, it is always simpler to publish mainstream stuff than new or controversial material. Gerlich has published so much that it is not important for him to have one peer-reviewed paper more at the cost of a lot of trouble with editors and reviewers.
Nevertheless, the number of comments to papers underlined that even review processes cannot prevent that scientific nonsense is published. I gained the experience that in one case my comments to a peer-reviewed paper were not published because my comments were classified as too harsh by the respective editor-in-chief. Obviously, he believed that it was more important for the journal to suppress my comments to a paper written by a member of his Editorial Board than to remove wrong equations from the literature. Probably, he also believed that my comment would damage the scientific career of this board member.
I was member of the AGU for 13 years. I canceled my membership in 2006 when I realized that someone was named AGU fellow who has published a lot of scientific nonsense (all papers were peer-reviewed) in the field of micrometeorology during the last five years. His contribution with which this nonsense was established in the literature has, meanwhile, been cited more than 80 times. It is the current basis for studying the exchange of carbon dioxide between the atmosphere and the biosphere.
Instead to lament that the article of Gerlich and Tscheuschner is not peer-reviewed, one should analyze what is right and what is wrong in this article. It is true that Gerlich and Tscheuschner are engaged in theoretical physics rather than in climate research. However, the energetics of the atmosphere, land, ocean, snow and ice covers are still based on physical laws. Therefore, they are well educated and prepared to study physical processes taking place within our climate system. Please, read Craig Bohren’s comments on the greenhouse effect. He is well known as an expert in atmospheric radiation. The differences between his opinion and those of Gerlich and Tscheuschner are rather marginal.
In my opinion the category “peer-reviewed papers” is fine for search committees, peer-unit committees and promotion committees and other ones because it is often simpler for committee members to count such papers than to understand the scientific content of them.
— Posted by Gerhard Kramm
457. January 29th, 2008 10:03 pm Having little response Kramm throws down the gauntlet:
Dear Mr. Pierrehumbert,
please, tell us what is wrong with the article of Gerlich and Tscheuschner (2007, http://arxiv.org/abs/0707.1161 ). It is true that this article is not peer-reviewed. However, this article is available for the (scientific public), more than most peer-reviewed papers. Therefore, we can debate it.
Here are some questions for you.
(1) Is their presentation of the radiative transfer equation incorrect?
(2) Is their physical interpretation of this equation wrong?
(3) Is it wrong that in the case of an integration of Planck’s blackbody radiation law over a finite range of the frequency (alternatively wavelength), the authors denoted it as filtered spectrum, the results differ from the power law of Stefan and Boltzmann?
(4) Do you believe that the tropopause region for which the anthropogenic radiative forcing is calculated can warm the nearly 65 K warmer Earth’s surface without any compensating changes?
(5) Is it true that a perpetual motion machine of second kind can exist?
(6) Give the various citations of greenhouse effect explanations listed by Gerlich and Tscheuschner evidence that this greenhouse effect really exist?
(7) Is the current explanation of the greenhouse effect physically correct?
Here is another explanation I found in the Glossary of the AMS:
“The heating effect exerted by the atmosphere upon the earth because certain trace gases in the atmosphere (water vapor, carbon dioxide, etc.) absorb and re-emit infrared radiation. Most of the sunlight incident on the earth is transmitted through the atmosphere and absorbed at the earth’s surface. The surface tries to maintain energy balance in part by emitting its own radiation, which is primarily at the infrared wavelengths characteristic of the earth’s temperature. Most of the heat radiated by the surface is absorbed by trace gases in the overlying atmosphere and re-emitted in all directions. The component that is radiated downward warms the earth’s surface more than would occur if only the direct sunlight were absorbed. The magnitude of this enhanced warming is the greenhouse effect. Earth’s annual mean surface temperature of 15°C is 33°C higher as a result of the greenhouse effect than the mean temperature resulting from radiative equilibrium of a blackbody at the earth’s mean distance from the sun. The term “greenhouse effect” is something of a misnomer. It is an analogy to the trapping of heat by the glass panes of a greenhouse, which let sunlight in. In the atmosphere, however, heat is trapped radiatively, while in an actual greenhouse, heat is mechanically prevented from escaping (via convection) by the glass enclosure.”
Obviously, this explanation is based on the following thought experiment: We consider the Earth without an atmosphere and calculate an temperature on the basis of a radiative equilibrium (absorbed solar radiation is equal to the isotropically emitted infrared radiation). For this calculation we assume that the temperature is uniform, the planetary albedo is 0.3, and the planetary emissivity is equal to unity. Then we obtain nearly 255 K and state that the difference between this value and the mean global temperature amounts to 33 K. Unfortunately, this uniform temperature of the radiative equilibrium has nothing to do with the mean global temperature derived from observations (see Essex et al., 2007: Does a Global Temperature Exist?, J. Non-Equilibrium Thermodynamics 32, 1-27). And the Earth is, by far, not a blackbody.
Sincerely yours
Gerhard Kramm
— Posted by Gerhard Kramm
717. February 4th, 2008 2:42 pm And Kramm continues to try to ignite a fire:
Re: # 682
Dear Mr. Lacis,
Gerlich and Tscheuschner (2007) have shown that most of your statements are not correct from a physical point of you.
Please explain, for instance, in which way the tropopause region for which the so-called anthropogenic radiative forcing was estimated can warm the earth’s surface which has a temperature of about 65 K higher than the tropopause region. This is not possible without any kind of compensating changes. If it would be then we would be able to build a perpetual motion machine of second kind. . . . (Snip as the comment goes on from here to other matters)
Sincerely yours
Gerhard Kramm
— Posted by Gerhard Kramm
735. February 4th, 2008 11:08 pm and gets a bite from Raypierre
Kramm continues to defend the unpublished and unreviewed article by Gerlich and Tscheuchner. I will repeat my previous challenge: If they are right, no greenhouse gas has any warming effect on any planet. So how do you account for the temperature of Earth and Venus, eh?
And I’ll add another: The very same radiative transfer equations which G&T say are invalid make a specific prediction for the spectrum of outgoing radiation from a planet. This can be compared with observations. It was done in the 1970’s from Tiros for Earth and the answer is in just fine agreement. If you want an even clearer cut example, you can use Mars, for which CO2 is by far the dominant greenhouse gas and water vapor is not much of a factor. The TES instrument observed the Martian CO2 spectrum. No problem there.
So let’s have less silliness about G&T and the greenhouse effect. If you can’t understand the flaws in their argument, you can at least understand that their claims are contrary to direct spectral observation.
— Posted by Raymond T. Pierrehumbert
753. February 5th, 2008 10:46 am Brian Valentine joins in
I regret that I see the necessity to step back into the rugby match again, as no one seems to have called time.
Dr Pierrehumbert has written: “If they are right, no greenhouse gas has any warming effect on any planet. So how do you account for the temperature of Earth and Venus, eh?:
Answers: a) water vapour b) clouds, of some 80% sulfuric acid, ranging in size from 0.01-10 micron, which would stabilize at the temperature and pressure of Venus (according to the Kelvin equation, modified for a change in surface tension according to the thermodynamically rigorous Gibbs-Tolman equation) and exhibit a certain internal reflectance, on the IR and in the visible portion of the spectrum (the angles of which were first worked out by Maxwell in his studies of rainbows)
“So let’s have less silliness about G&T and the greenhouse effect. If you can’t understand the flaws in their argument, you can at least understand that their claims are contrary to direct spectral observation”
WHOSE spectral observations, Dr Pierrehumbert???
eh???
— Posted by Brian Valentine
770. February 5th, 2008 6:43 pm Gerhard Kramm answers Raypierre:
Dear Dr. Pierrehumbert,
it is a fact that the manuscript of Gerlich & Tscheuschner (2007, http://arxiv.org/abs/0707.1161), in principle written as a review paper, is not peer-reviewed. Yesterday, I stated in one of my comments that the paper of Finnigan et al. (2003, Boundary-Layer Meteorology) is full of physical and mathematical errors, even though it is “peer-reviewed” and it became the guideline of the CO2 community engaged in micrometeorological field studies. Meanwhile, this paper of Finnigan et al. is cited more than eighty times in peer-reviewed journals (see Thomson’s Science Citation Index). This indicates that “peer-reviewed” is no longer a standard of quality in science.
The manuscript of Gerlich & Tscheuschner (2007) is online available for all of us. Therefore, one can debate it. Since I have served as a reviewer for several meteorological and geophysical journals, I may evaluate this article like a reviewer.
As a reviewer, I would suggest that the authors should shorten the introduction and especially the sections 3.1 to 3.4 because it makes no sense to me to list several improper statements on the physical meaning of the so-called greenhouse effect of the atmosphere. These sections also contain some citations with political background, for instance, “The Great Global Warming Swindle” which should be removed. The authors also cited Al Gore and that he did not understand the difference between absorption/emission on the one hand and scattering on the other hand. Al Gore is not a scientist. Therefore, this statement can be removed, too. Unfortunately, the statement of Gerlich & Tscheuschner that many climate scientists do not really understand this difference is a fact, but, nevertheless, within the framework of this context it is not necessary to mention it.
Chapter 2 and section 3.5 contains well known stuff on heat conduction, blackbody radiation and radiative transfer. In a review paper on the so-called greenhouse effect of the atmosphere it is more than wishful to find such stuff so that the common reader has the possibility to distinguish between the true greenhouse effect and the so-called greenhouse effect of the atmosphere.
Section 3.6 is only important for those people who are interested in the history of science. Probably, they know it so that one may remove this section from the manuscript.
Section 3.7 is most important because Gerlich & Tscheuschner demonstrate that the explanation of the so-called greenhouse effect of the atmosphere is based on a popular fallacy. This simple scheme of the planetary radiation balance for the Earth without an atmosphere (in principle, a thought experiment) is, indeed, highly unsuitable from a physical point of view. The reasons are: First, a uniform temperature which is deduced from the planetary radiation balance does not exist, and second, it has nothing to do with a globally averaged near-surface temperature. Close to the surface the temperature is strongly affected by various energetic processes, characterized by the complete energy balance, which, for instance, also includes the flux densities of sensible and latent heat and the advection of heat. (By the way, emission of IR radiation is related to the true surface temperature which usually differs from the temperature observed at the height of 2 meters or so above the surface.)
Our Moon, for instance, nearly fulfills the requirement of this though experiment of an Earth without atmosphere. It is well known that the Moon has no uniform temperature. There is not only a variation of the temperature from the lunar day to the lunar night, but also from the Moon’s equator to its poles. To calculate the temperature difference between lunar day and lunar night would not only require recognizing its rotation, but also the penetration of energy into the near-surface layers of the ground. Obviously, the latter is not considered in the planetary radiation balance. But also the rotation is not considered as correctly criticized by Gerlich & Tscheuschner.
If we accept that there is no uniform temperature, then we have to ask what the correct procedure of averaging is. Colleagues engaged in large-scale and meso-scale meteorological modeling know this problem that also occurs in the parameterization of subgrid scale processes. In their manuscript Gerlich & Tscheuschner demonstrate that a correct averaging would lead to highly awkward results.
Section 3.9 reflects basic knowledge in thermodynamics. Unfortunately, it seems to be indispensable to discuss it.
In chapter 4 of the manuscript the physical basis for climate science is presented. Obviously, the authors did not consider turbulent processes important for atmospheric and oceanic fluids. As a reviewer I would suggest to include it, even though an averaging, for instance, of the balance equation of entropy in the sense of Reynolds leads to some unsolved problems regarding the entropy flux density and the entropy production, and hence, the dissipation function because we will get additional unknowns.
In summary, Gerlich & Tscheuschner have shown that the common explanation of the so-called greenhouse effect is not very helpful. Their criticism is quite justified.
As a reviewer I would recommend the manuscript of Gerlich and Tscheuschner for publication with moderate revisions.
Sincerely yours
Gerhard Kramm
— Posted by Gerhard Kramm
Note Kramm's emphasis on section 3 of G&T's manuscript.
776. February 5th, 2008 10:33 pm Which Arthur Smith tears to bits
Gerhard Kramm’s review of the Gerlich and Tscheuschner polemic is correct in a couple of respects. Section 3.7 is definitely the key section. Let’s look at it in detail (based on “version 3″ from arxiv.org).
In section 3.7.1, Introduction, they set the agenda: “Though there exists a huge family of generalizations, one common aspect is the assumption of a radiative balance, which plays a central role in the publications of the IPCC and, hence, in the public propaganda. In the following it is proved that this assumption is physically wrong.”
So they are setting out to demolish the idea of radiative balance. Let’s see how they do.
Section 3.7.2 - A note on “radiation balance” diagrams. They claim “the popular climatologic radiation balance diagrams describing quasi-one-dimensional situations (cf. Figure 23) are scientific misconduct since they do not properly represent the mathematical and physical fundamentals.”
In fact, the radiation balance diagrams are completely physically well defined as an integral of radiative (or convective/evaporative) energy flux over the globe, averaged over time, at the various physically relevant altitudes. The fluxes are usually expressed in the diagrams in watts per square meter; that should make pretty clear what these diagrams refer to.
Nevertheless, they insist the diagrams are nonsense since the authors claim they don’t fit into one of the categories they believe they should fit into. In particular, they claim the diagrams “cannot represent radiation intensities” and refer back to two earlier sections (2.1.2 and 2.1.5) that talk about the details of radiation fields. They don’t even seem to consider the integration across Earth’s surface that makes a one-dimensional analysis as shown in the radiative diagrams perfectly well-defined.
One value of radiation balance diagrams is in forcing conservation of energy on the system - what goes in has to come out or, in the case of imbalance, has to warm or cool the planet beneath.
So the authors somehow are unable to understand a well-defined basic concept. Moving on…
Section 3.7.3: the case of purely radiative balance. Here they start off with an elementary error: equation 73 is valid only for a flat planet always facing the sun. Their numbers in table 10 are ridiculously wrong as a result. And why do they call epslion “phenomenological”? It’s a measurable albedo factor for sunlight, not some parameter somebody would adjust to fit some other agenda.
They correct themselves reluctantly in equation 76 (and 80) and table 11, but hit themselves with another elementary error in the claim that setting the albedo to 0.7 means you are saying “a grey body absorber is a black body radiator, contrary to the laws of physics.”
In fact, the low temperature of Earth’s surface relative to the sun means the spectrum radiated is at much longer wavelengths than the incoming radiation. And at those long wavelengths Earth is in fact essentially a full absorbing black body, while it is partially reflective for the incoming short-wave radiation. Those conditions are perfectly consistent with the laws of physics - and are exactly what happens here on this planet.
So error upon error upon error here. Well, what comes next?
Section 3.7.4 - “The average temperature of a radiation-exposed globe”. Here they put up a straw-man atmosphere-free planet and look at how averaging works for temperature, and for temperature to the fourth power. Obviously, you get different numbers. But that has little relevance to any argument any climatologist ever makes. When the temperatures are relatively close, as they are on our actual planet, the two averages come much closer. But in their straw man planet where the sun is always in the same position overhead on one side and never seen on the other, they get a much lower average temperature. Fine as a calculation - relevant? Even the Moon has an average temperature of some -23 degrees C, because it doesn’t lose all its heat on the dark side during the two-week night-time. The climatologist’s effective temperature is much closer to the real number for an actual rotating planet with a nonzero heat capacity.
Section 3.7.5 - “Non-existence of the natural greenhouse effect”. Here they take their -129 C average temperature on their straw-man planet and the fact that actual temperatures are about +15 C, and claim that the resulting 144 C “physical” greenhouse effect is evidence that “something must be fundamentally wrong here”. The only thing wrong is their idea that their straw-man is what anybody else is talking about.
The rest of this section comes from their confusion about the radiation balance arguments and what climate scientists mean when talking about cause and effect. They claim that “the radiation is locally determined by the local temperature.” Cause and effect here are simple: incoming solar energy and energy coming from the atmosphere heats the surface. Outgoing radiation (and other energy) from the surface is determined by whatever temperature the surface has gotten to. The radiation balance diagrams explain what happens when everything is back in a steady-state situation, but the instantaneous cause and effect is clear. The authors are making extraordinary claims here.
The next section rehashes the fourth-power vs first-power averaging problem. This only proves that a 30-degree temperature range across a new-straw-man planet makes less than half a degree difference to the average with the two methods. So a realistic planetary model, rather than their original straw man, might need a greenhouse effect of 33.5 degrees rather than 33. The authors ironically claim at this point they have proved there is “no longer any room for a natural greenhouse effect”. They have of course proved no such thing.
Section 3.7.7 is just incoherent. There is no global mean temperature? They’ve just calculated one, twice! Maybe a global mean fourth-power-of-temperature would be more physically relevant - but that’s exactly what the radiation diagrams look at (energy fluxes, which vary as fourth power of temperature).
3.7.8 and 3.7.9 finally look at a rotating globe with a (unexplained?) heat capacity lambda. They seem to believe no computer could solve their equations - well, no, they can’t be solved in analytic closed form. But they provide a very simple model that in fact is almost trivially integrable - engineers tackle differential equations ten times as hard before breakfast every morning. Really, “Rough estimates indicate that even these oversimplified problems cannot be tackled with any computer”!!! And when you solve it, you’ll get numbers very much like what you see on the Moon.
Section 3.7.10 seems to be an attempt to add an atmosphere to their straw-man models, but I doubt it would add much enlightenment. The more heat capacity you add to the system, the closer you get to the “effective” temperature that climatologists talk about, rather than their straw-man “physical” temperature.
Section 3.7.11 finally discusses CO2, based on some ancient papers from a fellow named Schack. I don’t think we need to delve into this too much, but their one statement that “He did not get the absurd idea to heat the radiating warmer ground with the radiation absorbed and re-radiated by the gas.” indicates pretty clearly that the authors of this paper are still very confused about radiation balance diagrams and the way the real greenhouse effect works.
And that’s it for the tremendously important section 3.7. Did we learn anything? The authors made many errors, displayed ignorance of several critical topics they claimed to be conversant with. They set up several straw-man models to attack them because of their unphysical nature, then set up a slightly more realistic straw-man and claimed it was too hard to solve. Nowhere did they prove anything about CO2 not causing greenhouse warming - they didn’t even get into discussing the meaning of the radiation balance diagrams that proves this, because they dismiss them out of hand.
Not a promising start. Is there another section of this paper you somehow feel is more representative? I’d be happy to demolish that too.
— Posted by Arthur Smith
789. February 6th, 2008 6:35 am guthrie replies to Brian Valentine
. . . Remember, Ray said, regarding the essay written by Gerlich and Tscheuschner that if they were correct, no “greenhouse gas” has any warming effect on any planet. I had a scan of it last night, and this does seem to be what it is arguing. However, you then responded that Venus was warmed by water vapour and Sulphuric acid etc. This is of course correct. The point I was trying to make, admittedly shortly before I went to bed, so I was not posting so clearly, was that if the “greenhouse effect” doesn’t exist, then you can’t say that water vapour etc on venus are keeping it warm. Now, it may be that you disagree with the Gerlich and Tscheuschner essay, in which case we have no reason to argue about this.
The essay did make the point that the name “greenhouse effect” is a misnomer, which is correct. I’d like to change it myself, but we seem to be stuck with it just now.
(some byplay excised)
799. February 6th, 2008 10:21 am Yr. hmble hare raises his ears above the wall
My thanks to G. Kramm who in 717 finally makes clear to me what Gerlich and Tscheuschner were trying to express in their Arxiv manuscript. It remains nonsense.
“Please explain, for instance, in which way the tropopause region for which the so-called anthropogenic radiative forcing was estimated can warm the earth’s surface which has a temperature of about 65 K higher than the tropopause region. This is not possible without any kind of compensating changes. If it would be then we would be able to build a perpetual motion machine of second kind.”
Neither they nor Kramm apparently can understand what is happening. Allow me to explain.
At equilibrium the Earth (including the atmosphere) must radiate the same amount of energy as it absorbs from the sun. If the amount of absorption is greater than the emission then something has to change so that the emission increases. As a general rule this means something has to warm up. Remember that radiation from the Earth in this context includes the atmosphere.
Without greenhouse gases the surface temperature would be about -20 C ON AVERAGE (right now the temperature in Barrow Alaska). Greenhouse gases absorb energy radiated from the surface, blocking a portion of the radiation that is emitted from the surface so it can’t escape to space diretly. A further portion of the atmospherically absorbed radiation is later radiated to space, a portion is radiated down to the ground and absorbed there. GH&K object that this contradicts the second law of thermodynamics.
It does not on several grounds. The net energy flow from the warmer surface flowing into the colder atmosphere is positive. There is no violation of the second law.
Then why do greenhouse gases “warm” the surface. Strictly speaking what greenhouse gases do is slow the rate of energy flow from the surface to space which requires the surface to warm until radiative balance is achieved.
An example (the numbers are not accurate but indicative). If the intensity of the sun at the surface was 300 W/m2 without greenhouse gases 300 W/m2 would be radiated to space from the surface. With greenhouse gases 200 are radiated to space and 100 to the atmosphere, of which 50 are radiated back to the surface and 50 to space. The sunlight is still pouring in at 300 W/m2 so the energy flow to the surface is 350 in and 250 out. The net energy input is +100 which warms the surface. The effect is a combination of solar radiative heating and the fact that the greenhouse gases block a portion of the long wavelength radiation to space and return it to the surface.
This is in the nature of an insulation, just as your coat (you know, the one you are wearing in Barrow) blocks a portion of the heat radiating from your body and returns it to your skin. The coat is colder than your body.
In short the sort of thing that even people with doctorates can fool themselves on, not a violation of the second law of thermodynamics.
— Posted by Eli Rabett
832. February 6th, 2008 10:40 pm which Kramm replies to (there was a bit of byplay with Jim Arndt)
Re: # 799
Dear Eli Rabett,
the so-called greenhouse effect of the atmosphere is commonly explained as followed (see Glossary of Meteorology, American Meteorological Society, http://amsglossary.allenpress.com/glossary/search?id=gr eenhouse-effect1):
“The heating effect exerted by the atmosphere upon the earth because certain trace gases in the atmosphere (water vapor, carbon dioxide, etc.) absorb and reemit infrared radiation.
Most of the sunlight incident on the earth is transmitted through the atmosphere and absorbed at the earth’s surface. The surface tries to maintain energy balance in part by emitting its own radiation, which is primarily at the infrared wavelengths characteristic of the earth’s temperature. Most of the heat radiated by the surface is absorbed by trace gases in the overlying atmosphere and reemitted in all directions. The component that is radiated downward warms the earth’s surface more than would occur if only the direct sunlight were absorbed. The magnitude of this enhanced warming is the greenhouse effect. Earth’s annual mean surface temperature of 15°C is 33°C higher as a result of the greenhouse effect than the mean temperature resulting from radiative equilibrium of a blackbody at the earth’s mean distance from the sun. The term “greenhouse effect” is something of a misnomer. It is an analogy to the trapping of heat by the glass panes of a greenhouse, which let sunlight in. In the atmosphere, however, heat is trapped radiatively, while in an actual greenhouse, heat is mechanically prevented from escaping (via convection) by the glass enclosure.”
This means that the radiation balance of the Earth without an atmosphere (I called it a thought experiment) is given by
(1 - a) S/4 = sigma T_e^4
Here, a is the planetary albedo, S = 1367 W/m^2 is the solar constant, sigma = 5.67E-8 W/(m^2 K^4) is the Stefan’s constant, and T_e is the temperature of the radiative equilibrium. It is considered as a uniform temperature for the whole globe. Using a planetary albedo of a = 0.3 leads to T_e = 255 K. Since the mean global near-surface temperature is of about 288 K the difference between both amounts to 33 K, as mentioned in the Glossary of the AMS.
As I already mentioned before, our Moon nearly satisfies the requirement of this thought experiment of an Earth without atmosphere. It is well known that the Moon has no uniform temperature T_e. There is not only a variation of the temperature from the lunar day to the lunar night, but also from the Moon’s equator to its poles. To calculate the temperature difference between lunar day and lunar night would not only require recognizing its rotation, but also the penetration of energy into the near-surface layers of the ground. Obviously, the latter is not considered in the planetary radiation balance. But also the rotation is not considered. These are facts.
To calculate a mean global surface temperature of the Moon on the known temperature distribution, it is necessary to use an averaging procedure, for instance, similar like that providing the mean global near-surface temperature. The same is true when we consider the Earth without an atmosphere.
If we formulate the energy balance at the Earth’s surface with an atmosphere we have not only to consider the radiation balance, but also the exchange of heat between the atmosphere and the underlying ground. This simple model of the radiation balance of the Earth without an atmosphere is physically wrong.
Your statement on the second law of thermodynamics is rather poor. Let me cite Wolfgang Pauli’s textbook on “Thermodynamics and the Kinetic Theory of Gases”. He describes Clausius’ explanation of the second law of thermodynamics. Following Pauli, “there does not exist a device which, working in a cycle, permits heat to be transferred from a reservoir at one temperature to one at a higher temperature without compensating changes”.
Your example with the coat gives evidence that you did not really understand the difference between heat conduction and transfer of energy by radiation . The material of a coat serves to reduce the heat conductivity so that the loss of energy by heat conduction is reduced. Inside the coat the temperature is nearly equal to the skin temperature, the temperature at the outside of the coat is governed by the energy balance which, of course, also contains the flux densities of sensible and latent heat.
By the way, it was much colder here in Fairbanks than in Barrow during the last three days. We had near-surface temperatures around - 40 degrees Fahrenheit (which corresponds to -40 degrees Celsius). And it is often colder in Interior Alaska than in Barrow.
844. February 7th, 2008 10:20 am Lazar's first comment on G&Ts thermodynamics
Gerhard Kramm @ 832;
Your statement on the second law of thermodynamics is rather poor. Let me cite Wolfgang Pauli’s textbook on “Thermodynamics and the Kinetic Theory of Gases”. He describes Clausius’ explanation of the second law of thermodynamics. Following Pauli, “there does not exist a device which, working in a cycle, permits heat to be transferred from a reservoir at one temperature to one at a higher temperature without compensating changes”.
You’re still wrong, and you’re not addressing Eli’s concrete physical example, just reiterating Clausius statement which you’re misapplying.
The first law of thermodynamics: [delta]E = Q - W
the change in internal energy E of a system is equal to the net transfer (Q - W) of energy into the system from the surroundings, which is equal to the net transfer by heat Q (conduction, convection, radiation) minus the net transfer by work W (work done by the system on the surroundings minus work done by the surroundings on the system).
In terms of a change in internal energy… W represents the net transfer of energy by work.
In terms of a change in internal energy… Q represents the net transfer of energy by heat.
Energy can and does transfer from colder surroundings to a warmer system, but a net transfer is forbidden (or extremely unlikely, depending on the size of the system).
IOW more energy flows the other way.
We did this in first-year undergrad physics. I mean, really. This can be considered in many ways;
Energy transfer on the microscopic scale, by conduction, particles with different kinetic energies colliding, by convection, turbulent flows, by radiation.
That matter emits radiation in a continuous spectrum.
The placing of two black bodies at different temperatures in radiative contact.
The Stefan-Boltzmann equation, and since you quoted a textbook I’ll quote Serway & Beichner, Physics for Scientists and Engineers fifth edition, page 628:
“As an object radiates energy at a rate given by Equation 20.18 [P = o A e T^4], it also absorbs electromagnetic radiation. If the latter process did not occur, an object would eventually radiate all its energy, and its temperature would reach absolute zero [this is before the quantum mechanics section]. The energy an object absorbs comes from its surroundings, which consists of other objects thar radiate energy. If an object is at temperature T and its surroundings are at a temperature T[0], then the net energy gained or lost each second by the object as a result of radiation is P[net] = o A e (T^4 - T[0]^4). When an object is in equilibrium with its surroundings, it radiates and absorbs energy at the same rate, and so its temperature remains constant. When an object is hotter than its surroundings, it radiates more energy than it absorbs, and its temperature decreases.”
Stefan-Boltzmann explicitly states a warmer system absorbs energy from cooler surroundings by radiation, which is also what Eli is stating.
Replace T with the surface temperature and T[0} with the lower troposphere temperature in the above equation, and you’ll get the radiative transfer by heat per second from the surface to the LT.
The surface temperature is higher than it would be without an atmosphere, this does not mean there is a net transfer of energy from the atmosphere to the surface, and there is no violation of the second law.
— Posted by Lazar
847. February 7th, 2008 12:24 pm which Eli echoed
I’ve expanded my comments on Kramm’s (#842) and G&T at
http://rabett.blogspot.com/2008/02/light-dawns-and-sun- sets-g.html
That post attracted about the best pithy summary of what the greenhouse effect is and a trenchant example,
Flavius Collium’s better way of putting this is
—-I’d summarize it that the greenhouse gases “hinder the cooling of earth’s surface.
Same if you use a resistor to heat a less insulated object vs a more insulated one - the insulation in both cases will always be colder than the object but the better insulated one will reach a warmer steady state.”—
If you think about it, this shows how Kramm’s 842 and his preceding comments are mistaken. The insulation is not heating the resistor, but hindering its cooling. The greenhouse gases are not heating the surface, but hindering its cooling.
— Posted by Eli Rabett
851. February 7th, 2008 3:16 pm Kramm tries to deal with Arthur Smith's comment:
Dear Arthur Smith,
in your comment # 776 you stated: “Section 3.7.4 - “The average temperature of a radiation-exposed globe”. Here they put up a straw-man atmosphere-free planet and look at how averaging works for temperature, and for temperature to the fourth power. Obviously, you get different numbers.” The equation in my comment # 832 describes this. It es used in many textbooks to quantify the greenhouse effect. Eli Rabett and some other defended it, even though it is physically inappropriate because a uniform Earth’s surface temperature does not exist. According to the power law of Stefan and Boltzmann the emitted radiative energy is dependent on the true temperature, not on a fictive equilibrium temperature.
It is a fact that in this simple radiation balance model the rotation of the Earth is ignored. This means that we would have only emisson of radiative energy on the dark side of the globe and absorption and reflection of solar radiation and emission of radiative energy of the bright side of the globe. Since the solar zenith angle also depends on the latitude we would have a variation of the Earth’s temperature from the equator to the poles. Therefore, we have to consider that the Earth’s surface temperature depends on longitude and latitude in quantifying the greenhouse effect. Consequently, the simple radiation balance model using a uniform surface temperature does not satisfy any requirement of a true radiation balance for an Earth without an atmosphere.
Therefore, Gerlich & Tscheuschner’s criticism on the quantification of the greenhouse effect is quite justified.
People like Eli Rabett completely ignore that no uniform Earth’s surface temperature exists. One may define it as a scientific misconduct. If it is economically or politically motivated, then we may denote it a scientific fraud.
Sincerely yours
Gerhard Kramm
— Posted by Gerhard Kramm
That last paragraph will come back to haunt Kramm
853. February 7th, 2008 3:35 pm And Kramm on the bunny
Re: # 847
Dear Eli Rabett,
obviously, you are not able to quote correctly.
In my comment # 832 (not # 842; counting is a lucky chance) I stated: “The material of a coat serves to reduce the heat conductivity so that the loss of energy by heat conduction is reduced. Inside the coat the temperature is nearly equal to the skin temperature, the temperature at the outside of the coat is governed by the energy balance which, of course, also contains the flux densities of sensible and latent heat.”
This has nothing to do with your quotation “The insulation is not heating the resistor”.
858. February 7th, 2008 5:19 pm Kramm gets short tempered with Lazar
Re: # 844
Dear Mr. Lazar,
obviously, it is necessary to talk about undergraduate physics.
First, it seems that you disagree with Wolfgang Pauli, Nobel Laureate and one of the greatest theoretical physicists. This is not a problem to me. However, then it is indispensable to underline why Pauli’s description is wrong.
Next, absorption and emission of radiative energy is related to a given wavelength (alternatively frequency or wave number), as formulated in Kirchhoff’s theorem from 1860 (see, e.g., Eqs. 47 and 48 of Gerlich & Tscheuschner, but you may also find it in Pais’ article in the 1st Volume on Twentieth Century Physics, 1995, or in Chandrasekhar, Radiative Transfer, 1960).
The power law was first published by Stefan in 1879. He used empirical findings. In 1884 Boltzmann presented a thermodynamic derivation. This means that your quotation “As an object radiates energy at a rate given by Equation 20.18 [P = o A e T^4], it also absorbs electromagnetic radiation” is highly awkward. You have to quote Kirchhoff’s theorem, but not the power law of Stefan and Boltzmann.
This power law is based on the whole spectrum. One can derive it by integrating Planck’s blackbody radiation law for all wavelengths ranging from zero to infinity. This can be performed analytically, and it is always an exercise for our students. But for finite ranges this integral has to be solved numerically. The results of the latter clearly differ from those of the former, as correctly pointed out by Gerlich & Tscheuschner.
Planck’s blackbody radiation law is also used to replace the source function in the radiative transfer equation when multiple scattering may be ignored, nearly satisfied in the case of infrared radiation (see, e.g., Chandrasekhar, 1960). This radiative transfer equation has to be solved numerically, too.
Feel free to take a look on the following quotations taken from the chapter 2 of the 4th report of the IPCC WGI (see Page 133):
“The definition of RF [radiative forcing] from the TAR and earlier IPCC assessment reports is retained. Ramaswamy et al. (2001) define it as ‘the change in net (down minus up) irradiance (solar plus longwave; in W/m^2) at the tropopause after allowing for stratospheric temperatures to readjust to radiative equilibrium, but with surface and tropospheric temperatures and state held fixed at the unperturbed values’.”
Furthermore:
“Radiative forcing can be related through a linear relationship to the global mean equilibrium temperature change at the surface (ΔTs): ΔTs = λ RF, where λ is the climate sensitivity parameter (e.g., Ramaswamy et al., 2001).”
These quotations underline that it is assumed that the tropopause region directly warm the nearly 65 K warmer Earth’s surface.
Sincerely yours
Gerhard Kramm
— Posted by Gerhard Kramm
865. February 7th, 2008 8:06 pm Lazar gets a bit back
First, it seems that you disagree with Wolfgang Pauli, Nobel Laureate and one of the greatest theoretical physicists. This is not a problem to me. However, then it is indispensable to underline why Pauli’s description is wrong.
I do not disagree with the statements by Wolfgang Pauli or Rudolf Clausius as you present them.
I do disagree with your interpretation.
[snip] You have to quote Kirchhoff’s theorem, but not the power law of Stefan and Boltzmann. [snip]
C’mon, stop arm-waving. Here the distinction between black body and gray is unessential, the question at hand is your idea that the greenhouse effect violates the second law. It still does not.
— Posted by Lazar
866. February 7th, 2008 8:29 pm Raypierre sees what he has wrought and is not totally pleased
It’s probably an exercise in futility to try to discuss Gerlich and Tseuchner any further in this forum, but here are a few additional bits of information in response to queries raised:
(1) Brian V. invokes water vapor, among other things. But G&T “disprove” the greenhouse effect of all gases, water vapor, too. At least, their reasoning applies to water vapor as well as anything else. Most of their reasoning also applies to clouds, particularly their criticism of the use of “radiative equilibrium” to compute planetary temperatures. Even if you allow them clouds, I defy anybody to account for the temperature of Venus on the basis of the radiative effect of the Venus clouds alone, without bringing in the CO2.
(2) The Mars spectral measurements I referred to are from TES on Mars Global Surveyor. TES took several hundred thousand spectra, and there are dozens of papers based on these. You can see a typical TES spectrum in Chapter 4 of my ClimateBook, but to go straight to the source, have a look at the resourses at tes.asu.edu . There’s a full list of papers there, but a typical one dealing with the spectra is:
Smith, M.D., J.L. Bandfield, and P.R. Christensen (2000). Separation of atmospheric and surface spectral features in Mars Global Surveyor Thermal Emission Spectrometer (TES) spectra, J. Geophys. Res., 105, 9589-9608.
NONE of this stuff would work if G&T were right, since it is based on exactly the same radiative transfer physics that is used in planetary climate.
— Posted by Raymond T. Pierrehumbert
874. February 7th, 2008 11:48 pm Eli points out that Kramm's quote from Pauli was incomplete in important ways
Once again I find myself in Gerhard Kramm’s debt for his post #832. It had been some time since I last read Pauli’s Thermodynamics and the Kinetic Theory of Gases, one of an excellent series available in translation from Dover Press for pennies ($7.95) and a pleasure to read (although I prefer Fermi’s Thermodynamics ($9.95))
Kramm accurately quotes Pauli on the Clausius version of the second law:
– “there does not exist a device which, working in a cycle, permits heat to be transferred from a reservoir at one temperature to one at a higher temperature without compensating changes”. —
but somehow omits the clause immediately following in parentheses:
–(that is, unless at the same time mechanical work is done, or energy is supplied from the surroundings by some other means)–
such as sunshine, which falsifies what Kramm has claimed.
— Posted by Eli Rabett
893. February 8th, 2008 11:27 am Brian Valentine makes some useful points about the second law
And to 874:
Clausius recognized that (mechanical) work could not be derived from the heat taken from a source that may not change temperature no matter how much heat is extracted (reservoir)
- without rejecting a portion of the heat so taken to a sink (reservoir) at a lower temperature.
This is entirely equivalent to the assertion that heat cannot be transferred from one reservoir to another reservoir at a higher temperature - without expending (mechanical) work.
The Second Law provides (absolute) upper and lower bounds for the magnitude of the work in any of the cases described above.
The use of the word “work” in both of the statements is absolute, and it is not possible to substitute the term “energy” for the term “work” (although “electrical” can be substituted for “mechanical” for example).
The Earth and its envelope are not closed to energy exchange, certainly, but that energy exchange does not result in a new condition for the second law.
So heat is not rejected from the Earth and the surrounding atmosphere to a convenient reservoir (such as the heaventree hung with humid nightblue fruit) without the expenditure of work;
that work, of course, is usually the pV work of the atmosphere.
The most common error in the application of the second law is the incorrect accounting of entropy in the examination of the entropy change of the “universe,” comprising a “system” and that system’s “surroundings.”
The second law only qualifies the sign of the first term distinguished by quotation marks above. Anything else, and you’re on your own.
— Posted by Brian Valentine
962. February 10th, 2008 4:54 pm Gerhard Kramm tries again
Re: #844 and #865
Dear Lazar,
I beg your pardon, but your statements are not correct.
First, the power law of Stefan and Boltzmann describes the emission over all wavelengths into the half space. This can be shown by integrating Planck’s blackbody radiation law over all wavelengths and by multiplying with pi. Planck’s formula has the units of an intensity and is considered as an example of isotropic radiation. (It is assumed that the prerequisite of local thermodynamic equilibrium is satisfied.) Integrating an isotropic intensity for 2 pi and pi/2 leads to the factor pi (see, e.g., Liou, 2002).
Second, Kirchhoff’s theorem described the interrelation between emission and absorption for a given wavelengths. This is independent whether we consider a black or a gray emitter because the special case of the absorptivity equal to unity is included.
In your comment #844 you quoted: “As an object radiates energy at a rate given by Equation 20.18 [P = o A e T^4], it also absorbs electromagnetic radiation. If the latter process did not occur, an object would eventually radiate all its energy, and its temperature would reach absolute zero [this is before the quantum mechanics section]. The energy an object absorbs comes from its surroundings, which consists of other objects thar radiate energy. If an object is at temperature T and its surroundings are at a temperature T[0], then the net energy gained or lost each second by the object as a result of radiation is P[net] = o A e (T^4 - T[0]^4). When an object is in equilibrium with its surroundings, it radiates and absorbs energy at the same rate, and so its temperature remains constant. When an object is hotter than its surroundings, it radiates more energy than it absorbs, and its temperature decreases.”
I substantially agree with this quotation. It clearly states that (a) emission of energy by radiation is accompanied with cooling of the surface (if no compensating changes prevent it), and (b) the tendency to a radiative equilibrium means that the emitter with the higher surface temperature will loose energy due to a negative net radiation balance until this net radiation balance becomes zero. This also means that its surface temperature decreases and approaches the equilibrium temperature. However, it does not mean that both the temperature of the cooler emitter and the temperature of the hotter emitter rise to higher values.
Consequently, the tropopause region for which the anthropogenic radiative forcing is estimated cannot warm, on average, the nearly 65 K warmer Earth’s surface.
Third, the so-called greenhouse gases have absorption bands. This means that the power law of Stefan and Boltzmann is not valid for such bands as correctly stated by Gerlich & Tscheuschner (they used the notion filtered spectrum for such a band). This is the reason why line-by-line calculations are performed using the radiative transfer equation.
Fourth, when we assume an average lapse rate of 6.5 K per kilometer for the troposphere, i.e., a decrease of the air temperature with height up to the tropopause, then the tropospheric regions close to the Earth’s surface have higher temperatures than the tropopause. The emission of radiation by these layers is much larger than that of the tropopause region.
Fifth, in my comment #858 I already quoted the chapter 2 of the 4th report of the IPCC WGI (see Page 133):
“The definition of RF [radiative forcing] from the TAR and earlier IPCC assessment reports is retained. Ramaswamy et al. (2001) define it as ‘the change in net (down minus up) irradiance (solar plus longwave; in W/m^2) at the tropopause after allowing for stratospheric temperatures to readjust to radiative equilibrium, but with surface and tropospheric temperatures and state held fixed at the unperturbed values’.”
Furthermore:
“Radiative forcing can be related through a linear relationship to the global mean equilibrium temperature change at the surface (ΔTs): ΔTs = λ RF, where λ is the climate sensitivity parameter (e.g., Ramaswamy et al., 2001).”
Please read this quotation carefully. On the one hand it is stated that the radiative forcing (RF) is estimated allowing for stratospheric temperatures to readjust to radiative equilibrium, but with surface and tropospheric temperatures and state held fixed at the unperturbed values. We may assume a radiative equilibrium at the top of the atmosphere, but not for the tropopause region. There is no basis for such an assumption. Then, the increase of the global mean equilibrium temperature is directly related to this radiative forcing. Have the surface temperature, first held fixed to estimate the radiative forcing, and the global mean equilibrium temperature nothing to do with each other? If emission is accompanied with a decrease of the emitter’s surface temperature, then is is sheer nonsense to hold any surface temperature or a vertical temperature profile fixed.
967. February 10th, 2008 7:10 pm G Kramm again
To # 866
Dear Dr. Pierrehumbert,
in my comment # 770 I pointed out that section 3.7 is the most important one in the manuscript of Gerlich & Tscheuschner. The key equations on radiative transfer used elsewhere in this manuscript can already be found in Chandrasekhar’s textbook on radiative transfer. It is the standard one and was cited by Gerlich & Tscheuschner.
The sole question is: Is the criticism of Gerlich & Tscheuschner on the explanation of the greenhouse effect justified or not?
The basis for this explanation is the equation of the planetary radiation balance given in my comment #770. When we recognize that, in contrast to the common assumption, the Earth not a blackbody radiator is, then this radiation balance must read
(1 – a) S/4 = eps sigma T_e^4 .
The symbols are explained in my comment #770, with exception of eps
— Posted by Gerhard Kramm
974. February 11th, 2008 4:25 am and here comes the cavalry (Gerlich and Tsheuschner themselves) Eli is going to leave out the personal harumphing but all the content is included.
Dear all,
Dear Dr. Raymond T. Pierrehumbert,
We (Gerhard Gerlich and Ralf D. Tscheuschner) are very sorry that we cannot reply to all statements published in Internet blogs since our “times on-line” are rather limited. Especially, we do not reply to semi-anonymous virtual climate pets like Eli Rabett and other Internet geniusses such as Gavin Schmidt, Stefan Rahmstorf and others at “Real Climate” or “Atmoz Blog” anti-scientific smear sites. (OK, had to leave some of this in for context and content). Most of them do know so little about physics such that they quote the second law of thermodynamics incorrectly in order to falsify our work. Even the difference between energy, work and heat seems to be unknown to these experts. This cannot be the basis of a scientific discussion.
. . . .My questions to you:
1. What is the most general formulation of the second law of thermodynamics?
2. What is your favorite exact definition of the atmospheric greenhouse effect within the frame of physics?
3. Could you provide me a literature reference of a rigorous derivation of this effect?
4. How do you compute the supposed atmospheric greenhouse effect (the supposed warming effect, not simply the absorption) from given reflection, absorption, emission spectra of a gas mixture, well-formulated magnetohydrodynamics, and unknown dynamical interface and other boundary conditions?
5. Do you really believe, that you can transform an unphysical myth into a physical truth on such a low level of argumentation?
END-OF-QUOTE. . . .
The main results of our paper are:
- the CO2 greenhouse effect is not an effect in the sense of a physical effect and, hence, simply does not exist;
- computer aided global climatology will not be science, if science is defined as a method to verify or falsify conjectures, according to the usual definition of science.
(We do not get into the ideas of e.g. Feyerabend “anything goes” here in that they do not apply to physics, in particular to applied physics, e.g. aeroplanes). . . . .
. . . .QUOTE (from Raypierre):
The two links you provide in fact point to the same paper. What you seem to be unaware of is that this paper has not been published in any journal. It appears only in the unreviewed ArXIV repository of manuscripts. This repository has no screening whatsoever as to the the content of the papers posted. Indeed, a look at the paper by anybody who has even a nodding acquaintance with radiation physics shows why they wouldn’t dare subject it to peer review. About 40 pages of this 90 page opus is in fact devoted to discussing the well-known flaws in the glass-greenhouse analogy sometimes used in simplified explanations of the phenomenon. These flaws have no bearing whatever on the manner in which the greenhouse effect is actually computed in climate models.
END-OF-QUOTE
We are not sure, whether you, Dr. Pierrehumbert, really know what you are talking about. The full theory of the atmospheric system must be a fusion of magnetohydrodynamics and radiation theory including earth’s gravity and rotation. The full theory should be a multi component theory and should include phase separation (interesting!), plasma physics, and highly involved boundary conditions which, in general, even cannot be written down. You, Dr. Pierrehumbert, first solve the turbulence problem, and then we can discuss the existence of a local thermodynamic equilibrium for the photon bath in which the atmosphere is embedded. Point us to only one source in the literature, where the CO2 term enters the fundamental equations (not the useless phenomenological toy model equations).
Mathematically, even within the most simplified models you cannot predict anything, because all these ones crudely approximate non-linear partial differential equations with unknown boundary conditions. There is simply no physical foundation of the computer models with and without CO2.
. . . . QUOTE (from Raypierre):
The Earth would be a solid ball of ice, and Venus would be 400 degrees colder than it is.
END-OF-QUOTE
In our paper, we clearly show that the standard calculation giving the 33 Celsius degrees for the greenhouse effect is wrong. Moreover, the Venus problem has nothing to do with the greenhouse effect, since in this case even the core presupposition is not fulfilled, namely that the sunlight reaches the ground.
QUOTE (from Raypierre):
And, as an aside, infrared weather satellites wouldn’t work either.
END-OF-QUOTE
Apparently, you do not know the subtle difference between absorption and warming. Read Chandrasekhar, read Unsoeld, read Schack.
QUOTE (from Raypierre):
Since the work was never published, it of course has never been discussed in the peer reviewed literature. The obvious flaws in the paper cannot be discussed easily in a comment box, but for a good general guide to the junk physics in this paper I refer the reader to Eli Rabett’s discussion at …
END-OF-QUOTE
Our paper is a brand new preprint submitted for publication. You are allowed to cite it in your future work according to the arXiv conventions. Apparently, you rank a peer reviewed published paper higher than a preprint, no matter of its content. Even so, really surprising in this context is that you attribute to the statements of a semi-anonymous virtual climate pet, namely Eli Rabett, the highest value.
What is this about?
Gerhard Gerlich
Ralf D. Tscheuschner
— Posted by Gerhard Gerlich and Ralf D. Tscheuschner
999. February 11th, 2008 2:30 pm Kramm takes a mulligan
Since my comment #968 was garbled, I try to submit it again.
To # 866
Dear Dr. Pierrehumbert,
in my comment # 770 I pointed out that section 3.7 is the most important one in the manuscript of Gerlich & Tscheuschner. The key equations on radiative transfer used elsewhere in this manuscript can already be found in Chandrasekhar’s textbook on radiative transfer. It is the standard one and was cited by Gerlich & Tscheuschner.
The sole question is: Is the criticism of Gerlich & Tscheuschner on the explanation of the greenhouse effect justified or not?
The basis for this explanation is the equation of the planetary radiation balance given in my comment #770. When we recognize that, in contrast to the common assumption, the Earth not a blackbody radiator is, then this radiation balance must read
(1 – a) S/4 = eps sigma T_e^4 .
The symbols are explained in my comment #770, with exception of eps, a planetary emissivity. If we use a value for eps less than unity, we will obtain an equilibrium temperature T_e higher than 255 K. For eps = 0.61 the temperature T_e amounts to 288 K. In such a case there would be no greenhouse effect. This means that this simple instance of a planetary radiation balance is inappropriate to explain the greenhouse effect, as correctly stated by Gerlich & Tscheuschner.
To calculated the absorption and emission of radiation across the atmosphere requires the radiative transfer equation. To estimate in which way both processes, that concurrently occur, affect any change of temperature, it is indispensable to use the balance equation for internal energy (alternatively enthalpy). In this balance equation the radiative flux occurs under the divergence sign. To solve this balance equation it is necessary to (numerically) integrate it from the Earth’s surface to the top of the atmosphere. This requires boundary conditions which must not be held fixed.
Note that in Modest textbook on “Radiative Heat Transfer” (2003) the true greenhouse effect is discussed, but not the atmospheric “greenhouse effect”, even though this textbook comprises 822 pages.
Let me quote physicist and meteorologist Dr. Craig Bohren, distinguished professor emeritus at the Pennsylvania State University. As a retired professor, he is not worried about losing or gaining funding based on his opinions.
He stated: “First off, let me say I consider the concept of a global mean temperature [upon which global warming statistics are based] to be somewhat dubious, and I say so in my recent book (with Eugene Clothiaux) Fundamentals of Atmospheric Radiation. A single number cannot adequately capture climate change. This number, as I see it, is aimed mostly at politicians and journalists.
The issue of global warming is extremely complicated, and it transcends science. Views on global warming are as much determined by political and religious biases as by science. No one comes to the table about this issue without biases. So I’ll state some of mine.”
Then he continued: “My biases: The pronouncements of climate modelers, who don’t do experiments, don’t make observations, don’t even confect theories, but rather [in my opinion] play computer games using huge programs containing dozens of separate components the details of which they may be largely ignorant, don’t move me. I am much more impressed by direct evidence: retreating glaciers, longer growing seasons, the migration of species, rising sea level, etc.
I have lived long enough to have seen many doomsday scenarios painted by people who profited by doing so, but which never came to pass. This has made me a skeptic. Perhaps global warming is an example of the old fable about the boy who cried wolf, but this time the doomsayers are, alas, right. Maybe, but I can’t help noting that some of the prominent global warmers of today were global coolers of not so long ago.”
(more… see http://www.usatoday.com/tech/columnist/aprilholladay/20 06-08-07-global-warming-truth_x.htm )
Dr. Bohren is not on Senator Inhofe’s list of the 400.
Sincerely yours
Gerhard Kramm
— Posted by Gerhard Kramm
1005. February 11th, 2008 6:30 pm Lazar puts it all together
Gerhard Kramm admits, in the statement below, to radiative transfer from both objects at lower temperatures to higher temperature objects as well as vice versa, and that therefore it is the net energy flow (from higher temp to lower) which is relevant to the second law.
I substantially agree with this quotation. It clearly states that (a) emission of energy by radiation is accompanied with cooling of the surface (if no compensating changes prevent it), and (b) the tendency to a radiative equilibrium means that the emitter with the higher surface temperature will loose energy due to a negative net radiation balance until this net radiation balance becomes zero. This also means that its surface temperature decreases and approaches the equilibrium temperature. However, it does not mean that both the temperature of the cooler emitter and the temperature of the hotter emitter rise to higher values.
Consequently, the tropopause region for which the anthropogenic radiative forcing is estimated cannot warm, on average, the nearly 65 K warmer Earth’s surface.
Eli has pointed out the role of the sun as a “compensating change” in the statement of Pauli…
Kramm accurately quotes Pauli on the Clausius version of the second law:
– “there does not exist a device which, working in a cycle, permits heat to be transferred from a reservoir at one temperature to one at a higher temperature without compensating changes”. —
but somehow omits the clause immediately following in parentheses:
–(that is, unless at the same time mechanical work is done, or energy is supplied from the surroundings by some other means)–
such as sunshine, which falsifies what Kramm has claimed.
Everything falls into place quite easily.
Examining Kramm’s last statement…
Consequently, the tropopause region for which the anthropogenic radiative forcing is estimated cannot warm, on average, the nearly 65 K warmer Earth’s surface.
… the above is a failure of semantics or logic, and is only true (ish, depending on precisely what he means by ‘warm’ and what the initial conditions are), in the absence of energy input from the sun.
The net energy flow between the Earth surface and atmosphere is from the warmer surface to the cooler atmosphere. The net energy flow between the sun, the surface and the atmosphere, is from the warmer sun to the cooler earth and the cooler atmosphere. Increasing GHGs increases the amount of energy received by the surface, which in turn raises the surface temperature until the energy emitted equals the amount received per unit time, but since this does not change the direction of the net energy flow in either case from warmer to cooler, the second law is not violated.
— Posted by Lazar
1009. February 11th, 2008 8:41 pm Eli takes another shot
Gerhard Kramm in #999 (Darn Tilo nipped Kim out for 1000) makes another common mistake when he says
–The basis for this explanation is the equation of the planetary radiation balance given in my comment #770. When we recognize that, in contrast to the common assumption, the Earth not a blackbody radiator is, then this radiation balance must read
(1 – a) S/4 = eps sigma T_e^4 .
The symbols are explained in my comment #770, with exception of eps, a planetary emissivity. If we use a value for eps less than unity, we will obtain an equilibrium temperature T_e higher than 255 K. For eps = 0.61 the temperature T_e amounts to 288 K. In such a case there would be no greenhouse effect.–
He fails to recognize that the albedo and emissivity Kramm’s eps) of the Earth are functions of wavelength and that for the infrared his eps is on average pretty close to 1 (btw .95 and 1. See for example the MODIS emissivity library
http://www.icess.ucsb.edu/modis/EMIS/html/em.html
Here is another study for sea water eps ~.97
http://saf.met.no/docs/vsrep_Merchant.pdf
Both should satisfy data fans out there.
This means that there is a small error using an eps of 1, (1-5% at the outside) but not the 40% error Kramm referred to. I shall have to read Gerlich and Tscheuschner’s article again to see if they too make this error. It would not surprise me as many of Kramm’s errors repeat theirs
Lazar in 1005 accurately summarizes Kramm and Gerlich and Tscheuschner’s basic error with respect to the second law. Brian Valentine had an excellent statement of the second law situation somewhere above.
1010. February 11th, 2008 10:41 pm Arthur Smith does a better job than Eli
There’s an awful lot to respond to, and for one I am definitely getting exhausted by it all. However, there’s one very small point I’d like to focus on with Drs. Kramm, Gerlich and Tscheuschner (and G and T’s comments here in #974 are much appreciated for their willingness to get involved).
The detail I want to get into here is what exactly G and T proved in their paper on the issue of a planet with no “greenhouse” absorption. That is, the bulk of the discussion in section 3.7.
Gerlich and Tscheuschner claim (in #974) “In our paper, we clearly show that the standard calculation giving the 33 Celsius degrees for the greenhouse effect is wrong.” Dr. Kramm seems to echo this in earlier comments on this thread - first that “one should analyze what is right and what is wrong in this article” (#180), and “We consider the Earth without an atmosphere and calculate an temperature on the basis of a radiative equilibrium […] Then we obtain nearly 255 K and state that the difference between this value and the mean global temperature amounts to 33 K. Unfortunately, this uniform temperature of the radiative equilibrium has nothing to do with the mean global temperature derived from observations […] “ (#457) and
“This simple scheme of the planetary radiation balance for the Earth without an atmosphere (in principle, a thought experiment) is, indeed, highly unsuitable from a physical point of view. The reasons are: First, a uniform temperature which is deduced from the planetary radiation balance does not exist, and second, it has nothing to do with a globally averaged near-surface temperature. […] Our Moon, for instance, nearly fulfills the requirement of this though experiment of an Earth without atmosphere. It is well known that the Moon has no uniform temperature. There is not only a variation of the temperature from the lunar day to the lunar night, but also from the Moon’s equator to its poles. To calculate the temperature difference between lunar day and lunar night would not only require recognizing its rotation, but also the penetration of energy into the near-surface layers of the ground. […] If we accept that there is no uniform temperature, then we have to ask what the correct procedure of averaging is. Colleagues engaged in large-scale and meso-scale meteorological modeling know this problem that also occurs in the parameterization of subgrid scale processes. In their manuscript Gerlich & Tscheuschner demonstrate that a correct averaging would lead to highly awkward results.” (#770)
and in #851, Kramm responds to my comments: “[…]it is physically inappropriate because a uniform Earth’s surface temperature does not exist. Therefore, we have to consider that the Earth’s surface temperature depends on longitude and latitude in quantifying the greenhouse effect. Consequently, the simple radiation balance model using a uniform surface temperature does not satisfy any requirement of a true radiation balance for an Earth without an atmosphere.”.
If I may restate the point you have been repeating here:
(A) Earth does not have a uniform surface temperature (with or without a “greenhouse” effect), therefore
(B) the “average” surface temperature does not correspond to the radiated energy from the surface, so therefore
(C) there is no need for a “greenhouse” effect to warm the surface.
Is that the gist of the argument?
I hope I’ve got it. Here’s the problem with it: G&T actually proved something quite important in their section 3.7.4 - the average temperature is always lower than the “effective” temperature. This follows from a simple inequality: ((T1+T2)/2)^4 is less than or equal to (T1^4 + T2^4)/2; ie. the fourth power of the average temperature is always less than the average fourth-power of temperatures.
Now, the fourth-power is important for the surface because the surface, composed of solid or liquid materials, absorbs radiation across the thermal region essentially completely in the continuum, and so is a very good “black body”. So for radiation directly from the surface, the Stefan-Boltzmann law holds almost everywhere. That means the total radiated energy from the surface can be calculated as the integral over Earth’s surface of the fourth power of the local temperature multiplied by the appropriate constant.
Furthermore, this integral can be divided by Earth’s surface area to get an average of the fourth power of the temperature. From what G&T prove, that average is always greater than or equal to the fourth power of the average temperature. Therefore, the radiated energy from Earth’s surface, when the average temperature is calculated as it is now at about 15 degrees C, is always greater than what would be radiated by a planet at a uniform temperature of 15 degrees C.
In addition to knowing the average temperature of the planet at 15 degrees C or 288 K, we also know the average incoming solar radiation: as you point out and as G&T calculate, that is equivalent to the radiation emitted by an atmosphere-free planet at a uniform temperature of 255 K. Given that the temperatures on our and any planet are not uniform, we can use the same relation to show that the average temperature on such an atmosphere-free planet that emits at that average radiation level (i.e. has that same average fourth-power of temperature) has to be *less* than 255 K.
So we have 2 input facts:
(1) Earth’s present temperature is an average 288 K
(2) Incoming solar energy corresponds to the thermal emissions from a planet with a uniform temperature of 255 K
and therefore from the inequalities we have two more facts we can deduce, without question:
(3) Outgoing thermal radiation from Earth’s surface is on average equal to radiation from a uniform planet with a temperature higher than 288 K
(4) Incoming solar energy corresponds to what a real atmosphere-free planet would emit with an average temperature of *less than* 255 K.
If you combine (2) and (3), you see there is a discrepancy of *at least* 33 degrees between the uniform-planet temperatures corresponding to the levels of outgoing and incoming radiation for Earth. If you combine (1) and (4) similarly, you see there is a discrepancy of *at least* 33 degrees between the actual average temperature of Earth as it is and the average temperature that a greenhouse-free Earth would have based on just incoming solar energy.
So from your premises as I summarized above (A, B, C); (A) I think we all agree with; the average temperature of the Earth’s surface reflects a wind range of local temperatures and day/night variations.
But for (B), this lack of uniformity does not remove the relationship between temperature and radiation entirely, but simply puts a lower bound on the outgoing energy flow for a given average temperature, or alternately puts an upper bound on average temperature given the energy flow.
And therefore, contrary to your conclusion (C), there remains a discrepancy of *at least* 33 K that needs to be accounted for. And the so-called “greenhouse” effect is in fact the way to understand it.
As Ray Pierrehumbert has repeatedly asserted here, if your argument were correct, there would be no greenhouse effect, and by your own calculations, Earth’s surface would have an average temperature of less than 255 K. There is no getting around these inequalities.
Do you agree with this logic? If not, please state clearly what the issue is. Atmospheric absorption has nothing to do with the discrepancy at issue here. Thanks.
If this thread closes before you can respond, you may want to comment at the copy I have posted here:
http://www.altenergyaction.org/mambo/index.php?option=c om_content&task=view&id=132&Itemid=28
— Posted by Arthur Smith
1018. February 12th, 2008 2:19 pm Kramm refers to Eli
You quoted: “Kramm accurately quotes Pauli on the Clausius version of the second law:
– “there does not exist a device which, working in a cycle, “. —
but somehow omits the clause immediately following in parentheses:
–(that is, unless at the same time mechanical work is done, or energy is supplied from the surroundings by some other means)–”
The statement between the parentheses is an additional explanation to compensating changes, nothing more. People, well familiar with thermodynamics know that. Obviously, you did not.
Therefore, it is not surprising to me that you further wrote
“such as sunshine, which falsifies what Kramm has claimed.”
This statement underlined that you are not able to understand Pauli’s explanation. Your statement is highly awkward because the compensating changes are necessary to transfer heat from a colder to a warmer reservoir, but not in the opposite direction.
Solar radiation reaching the Earth’s surface, where a portion of it is converted into heat, guarantees that the surface temperature is higher than that of the tropopause region.
I use the notion perpetual motion machine of second kind. I contrast to perpetual motion machine of first kind which is related to the first law of thermodynamics, the that of the second kind is related to the second law of thermodynamics. It means the following:
One first considers the transfer of heat from a colder reservoir to a warmer one so that the latter becomes still warmer (1st step), then in a 2nd step this surplus of heat in the warmer reservoir is transferred to a machine in which it is converted into mechanical work on the basis of the best possible efficiency (that of a Carnot process). The remaining amount of heat is then transferred to the colder reservoir.
This describes that a machine working in a cycle to produce mechanical work by transferring heat from a reservoir at one temperature to one at a higher temperature. Such a machine is in contradiction to the second law of thermodynamics.
I suggest to read section 3.9 of the manuscript of Gerlich & Tscheuschner carefully.
Sincerely yours
Gerhard Kramm
— Posted by Gerhard Kramm
1020. February 12th, 2008 3:54 pm and Kramm replies to Arthur Smith
Re: # 1010
Dear Arthur Smith,
I beg your pardon, you are barking up the wrong tree.
In science it is indispensable to recognize observations. The so-called planetary radiation
balance equation,
(1 - a) S/4 = eps sigma T_e^4,
is far away from such observations. This equation can be found in many textbooks (mainly without eps). As I already stated, this equation is based on a thought experiment for an Earth without atmosphere to estimate the greenhouse effect. Using a = 0.3 (which is based on satellite observations for the whole Earth-atmosphere system), S = 1367 W/m^2 and eps = 1 (assumption of a blackbody radiator) one gets T_e = 255 K. The globally average near-surface temperature amounts to 288 K; this value differs from T_e by 33 K, usually considered as the greenhouse effect. So far, so bad.
Obviously, you are not able that a uniform equilibrium temperature does not exist. As I already explained, from our observations we know that the local radiation balance depends on longitude (day-to-night dependency) and latitude (dependency of the solar zenith angle on the latitude). Consequently, we can only derive a temperature from a local radiation balance because the uniform equilibrium temperature for the whole globe has nothing to do with the local radiation balance (if we consider the Earth with an atmosphere, we have also include fluxes of sensible and latent heat as well as the heat transfer within the soil and within the ocean). Do you deny these facts?
By the way, the Earth is a gray body emitter (eps is less than unity), rather than a blackbody emitter. Budyko, for instance, used eps = 0.95 and a = 0.33 to calculate T_e = 255 K.
We can globally average over these temperatures calculated on the local radiation balance equations. Such an averaging procedure must be in agreement with the averaging procedure used to calculate the global mean near-surface temperature. Otherwise, we would compare apples with pears.
In their section 3.7 Gerlich & Tscheuschner listed additional reasons why this simple planetary radiation balance equation is far from reality.
Consequently, the simple planetary radiation balance equation is unsuitable in estimating a greenhouse effect. This is what I already stated, nothing more.
Sincerely yours
Gerhard Kramm
— Posted by Gerhard Kramm
1022. February 12th, 2008 4:55 pm George Smith explicitly raises the issue of averaging temperatures
In reading Dr Arthur Smith’s analysis above relating to black body radiation, and its appropriateness for climate discussion; I see he follows a reasoning, I have also mentioned here which seemingly drew no response (other than guffaws from Dano whoever that is).
Some have said the earth is not a black body therefore Planck’s law does not apply. But then I have seen other citations to the effect that in the Infra-red spectrum, where the earth radiates, it is quite close to a black body; or at least a grey or some other color body.
In any case, one should expect the total radiation (per unit area) to be more closely matched by a fourth power relationship, than a linear one; so WHY average the temperature over time and space; and then try to do a radiation flux balance between earth IR and incoming solar.
The earth’s cooling processes are considerably more complicated than simple Planckian radiation, since direct conduction, convection and phase changes (evaporation) transpor large amount of heat from the surface to the atmosphere.
BUT, when it comes to the effect of CO2 or other GHGs, the only thing that is of interest is the approximately black body EM radiation; that is what CO2 absorbs in the 15 micron band.
The earth’s IR spectrum measured at the surface may be very close to Black body. The infra-red handbook shown many graphs of common terrains like grass, emitting good looking blck body like spectra. But by the time you get some height above the ground, then the GHG absorptions do take chunks out of that spectrum; but what remains still is following a more fourth power law, than a linear one.
Now it is well known that if you add any periodic variation to a stationary variable, and then average ove a complete cycle that you get the same average value as if the cyclic variation was absent. the cyclic part integrates to zero over any complete cycle.
But now if you raise that cyclic expression to the fourth power, you produce a power series with five terms, one of which is the frourth power of the average, and two of the remaining four always integrate to zero over any complete cycle; but the other two do not integrate to zero; and they always add a POSITIVE amount to the integrated total. A simple calculation will show that the last of the remaining two terms is usually negligibly small, but the middle term produces a real positive offset, that is significant in terms of the 24 hour day-night temperature cycles on earth, and also the annual seasonal cycle.
Now that is just the temporal part of the radiation function, but when you add in the spatial variation over the planet, you get an even bigger spatial effect, so that the range over true black body radiation over the planetary temperature range is more than a factor of 11:1. when you throw in some emissivity values, and perhaps some spectral emissivity variation as well; the range of radiant intensity may be even greater than 11:1.
Certainly at the absorption end, the earth has a good deal of black body appearance. Since sea water has a refractive index of about 1.33, the Fresnel reflection coefficient for normal incidence is about 2%, but when you integrate over a complete hemisphere, the total reflection is between 3 and 10% depending on what assumptions you make. Certainly, over the tropical midday deep oceans, the ocean absorptance must be in teh range of 97-98%, since the near normal incident radiation simply goes on down till something absorbs it.
So the 70 % of the earth surface that is ocean must have a fairly good grey body absorption spectrum with an absorptance of over 95%.
Now one can’t invoke Kirchoff’s law to claim the emission matches the absorption, because Kirchoff only applies in the case of thermodynamic equilibrium, and with the sun going around the earth each 24 hours; there is no way that thermodynamic equilibrium is ever reached. But some sort of 4th power Temperature function of total radiation is still appropriate.
Now I always presumed that meteorologists used this sort of information to deduce what the weather was going to do in the next five days; and then I also mistakenly presumed that if you integrated the weather over decade or century time scales, that you would be modelling climate.
How wrong I was. You chaps evidently just average everything out to get one mean temperature, and then you invent something you call a forcing, and you apply that to a fictitious system that isn’t even close to what the planet is doing. That’s probably why your “models” won’t run backwards, and replicate the past history. Why don’t you do what the planet itself does, and apply the laws of physics in real time.
A solar photon encountering the earth has a lifetime of about a millisecond; then it is done with whatever it is going to do; but somehow you don’t account for it for decades or hundreds of years. You models have no predictive power past the time of the very last measured datum entered into them.
And why don’t you bone up on sampled data theory while you are at it (that’s not climatology though; probably information theory), and figure out whether any of you global data gathering schemes comes even close within orders of magnitude to the requirements of the Nyquist sampling theorem. Well I can save you the trouble because your methodology doesn’t come close, and even a factor of two failure to comply makes even your average corrupted by aliassing noise and unrecoverable.
— Posted by George E. Smith
1024. February 12th, 2008 6:10 pm Kramm again replies to Eli
I used this example to demonstrate how the amount of the greenhouse effect depends on the emissivity. Since I made some calculations using Gaussian error propagation principles, I also know the uncertainty of such estimates.
It might be that you have recently recognized that absorptivity, emissivity and scattering is dependent on the wavelenght. I know that since I was a graduate student of Erhard Raschke in the seventies. I also measured solar and infrared radiation abord the German research vessel in the northeastern part of the Atlantic Ocean 30 years ago.
I already mentioned that the power law of Stefan and Boltzmann is an integral law, i.e., it includes all wavelengths. This can be demonstrated the best by integrating the Planck function over all wavelengths, i.e., from zero to infinity. However, since the Planck function has the units of an intensity, it is also necessary to integrate over the half space. This is the reason why the factor pi occurs. Feel free to take a look into Kramm & Herbert, “Heuristic derivation of blackbody radiation laws using principles of dimensional analysis” (J. Calcutta Mathematical Society, 2007). It is also available under http://arxiv.org/abs/0801.2197 .
To quote Lazar is a nice joke because he quoted your insight into the second law of thermodynamics (see my comment # 1018). It sounds like so to me: Somebody makes a statement without any justification, and another used it to blame any opponent, eventually adopted by the former. It might be that you and Lazar have read many issues of the Boulevard Press for adopting its standards.
Sincerely yours
Gerhard Kramm
— Posted by Gerhard Kramm
1025. February 12th, 2008 7:03 pm Lazar stick to the second law:
#1018 Gerhard Kramm writes;
I use the notion perpetual motion machine of second kind. I contrast to perpetual motion machine of first kind which is related to the first law of thermodynamics, the that of the second kind is related to the second law of thermodynamics. It means the following:
One first considers the transfer of heat from a colder reservoir to a warmer one so that the latter becomes still warmer (1st step), then in a 2nd step this surplus of heat in the warmer reservoir is transferred to a machine in which it is converted into mechanical work on the basis of the best possible efficiency (that of a Carnot process). The remaining amount of heat is then transferred to the colder reservoir.
Gerhard Kramm clearly means the (internal) energy of the warmer reservoir rises when heat is transfered (1st law).
This describes that a machine working in a cycle to produce mechanical work by transferring heat from a reservoir at one temperature to one at a higher temperature. Such a machine is in contradiction to the second law of thermodynamics.
Does ‘heat transfer’ imply a one-way transfer of energy or does it mean a net transfer of energy? Since the internal energy of the warmer reservoir increases, and since Kramm has admitted energy flows in both directions by radiation, it must be the latter. Heat transfer is a net transfer of energy (which also comes from the 1st law, E being a state function of the system).
For the umpteenth time, the net transfer of energy is from the warmer surface to the cooler atmosphere.
The surface cools to the atmosphere.
When GHGs increase, the rate of cooling decreases, whilst the energy input from the sun remains constant.
So the surface temperature increases.
Cooling rate, energy out, decreases.
Heating rate, energy in, remains constant.
Temperature rises.
No perpetual motion machine.
Three possibilities…
A century of work in a discipline consisting of (tens of thousands?) of scientists, many, if not most, being graduates in physics or chemistry with doctorates, as well as the world’s scientific societies, institutions, and journals, all ignored the second law, or…
The second law is wrong, or…
Kramm, Gerlich and Tscheuschner are wrong on the second law.
Hmmm.
I think I’ll sleep easy tonight.
— Posted by Lazar
1027. February 12th, 2008 10:42 pm Arthur Smith replies to Kramm, but also to George Smith
Dr. Kramm (#1020) - you are not responding to my specific questions. Let me reiterate my questions, then discuss the new issues you raise.
First: the summary of your earlier arguments to me appears to be, once again:
(A) Earth does not have a uniform surface temperature (with or without a “greenhouse” effect), therefore
(B) the “average” surface temperature does not correspond to the radiated energy from the surface, so therefore
(C) there is no need for a “greenhouse” effect to warm the surface.
You seem to echo these arguments again in your #1020 without acknowledging specifically that I have stated your case in a way you agree with. Have I? You say this time: “As I already explained, from our observations we know that the local radiation balance depends on longitude (day-to-night dependency) and latitude (dependency of the solar zenith angle on the latitude). […] Consequently, the simple planetary radiation balance equation is unsuitable in estimating a greenhouse effect. This is what I already stated, nothing more.”
However, from my discussion in #1010, which I hope you considered in detail, the planetary “radiation balance equation” can be decomposed into two terms, both of which have real meaning and can be obtained to a very good approximation directly from observations. This appears to be contrary to your claim that “the so-called planetary radiation balance equation […] is far away from such observations.”
First, incoming radiation from the sun averaged over Earth’s surface: (1-a) S/4. This is the energy per unit time and per unit surface area reaching the surface from the outside world. This can be obtained simply from geometry and measurements of radiation from the Sun (S) and Earth’s albedo (a) in visible light.
Second, outgoing thermal radiation from Earth’s surface, leaving aside all discussion of latent heat and other energy flows, can be obtained from temperature measurements and knowledge of emissivity in the thermal wavelength range; this is an integral over Earth’s surface area and over a suitable time cycle (a year, say) of epsilon sigma T^4, where epsilon is local emissivity (in most places 95% or more as you note) and T is local temperature. We have plenty of temperature measurement data to be able to estimate this outgoing total thermal radiation to within a small percentage. The average, obtained by dividing the total by Earth’s surface area and the time period used, gives an average per-unit-area per-unit time value for outgoing energy from Earth’s surface.
So we have two numbers we can obtain directly from observations: incoming solar radiation to Earth’s surface, and outgoing thermal radiation from Earth’s surface. For a planet with no “greenhouse effect”, there is no other significant source of energy to the surface, so given the other energy flows from the surface (convection and latent heat) under a positive lapse rate, the thermal radiation flow must be less than the incoming solar energy.
And yet, when we measure the numbers for the Earth, the outgoing radiation amounts to 63% *more* than the maximum possible total coming in from the sun (there’s even less actually reaching the surface from the sun due to some absorption by the atmosphere). This corresponds to the 33 degree difference usually quoted. All Gerlich and Tscheuschner actually prove in their section 3.7 is that when you look at average temperature, the standard radiation balance equation turns into an inequality (when you substitute the average T for T_e in your equation #1020) - but the inequality is in the wrong direction: T_e^4 is greater than (average T)^4. So the balance equation as an inequality only leaves us with more that is unexplained, if you have no greenhouse effect. To be clear, the inequality applies when considering all radiation flowing in to the planet, and all radiation leaving the surface, integrated over a suitable period of time, under conditions of overall balance (no net energy increase or decrease in the planet itself).
Do you agree with this logic? And if not, please state clearly where is your point of disagreement.
Now, to the new items you raise in your #1020. First, if I understand your paragraph beginning “Obviously” correctly, you mention “Consequently, we can only derive a temperature from a local radiation balance because the uniform equilibrium temperature for the whole globe has nothing to do with the local radiation balance” - you are raising a topic of “local radiation balance”, and using such a relationship to derive local temperatures. But why would there be a local balance? During daytime the temperatures rise in response to incoming sunlight; during the night they fall with no sun. There may be occasional points where incoming and outgoing radiation would balance, but that is not what determines local temperature on a planet where the surface absorbs energy with a nonzero heat capacity. In any case, the relationship in question is not temperatures derived from a radiation equation, but actual measured temperatures, and the global balance across the whole planet, over time, that must be there if the planet is not to be continually accumulating (or releasing) more and more energy.
If you are trying to describe the situation on a model planet different from the ones used by G & T, then state your model clearly. If you are talking about one of G&T’s model planets, state which one. You also claim “In their section 3.7 Gerlich & Tscheuschner listed additional reasons why this simple planetary radiation balance equation is far from reality.” - but I find no such reasons when I read that section (only considerable support for the inequality mentioned above), so please state specifically in your own words what you believe their reasons are for such a claim.
Finally, you also state “We can globally average over these temperatures calculated on the local radiation balance equations. Such an averaging procedure must be in agreement with the averaging procedure used to calculate the global mean near-surface temperature. Otherwise, we would compare apples with pears.” Aside from the odd concept of temperatures calculated from local radiation balance, surely there is only one way to average temperatures across the globe: integrate temperature over the surface, then divide by surface area. Do you have something else in mind? And why are you talking about “near-surface” as opposed to “surface” temperature - outgoing thermal radiation comes from the surface, not the “near-surface”!
To return to the main question I have for you, Gerlich, and Tscheuschner: observations on Earth of incoming solar radiation and surface temperature show unequivocally that there is at least 63% more energy leaving Earth’s surface than could possibly be coming from the sun. If this additional energy is not coming from greenhouse warming, where do you believe it comes from? How do you account for the discrepancy?
— Posted by Arthur Smith
1029. February 13th, 2008 1:35 am Eli replies to Kramm, a bit testily
Gerhard Kramm raises some interesting questions along the line of if cows were horse pigs would fly. Kramm now writes in #1024
–I used this example to demonstrate how the amount of the greenhouse effect depends on the emissivity –
to justify his writing in #999
—The symbols are explained in my comment #770, with exception of eps, a planetary emissivity. If we use a value for eps less than unity, we will obtain an equilibrium temperature T_e higher than 255 K. For eps = 0.61 the temperature T_e amounts to 288 K. In such a case there would be no greenhouse effect. In such a case there would be no greenhouse effect. This means that this simple instance of a planetary radiation balance is inappropriate to explain the greenhouse effect, as correctly stated by Gerlich & Tscheuschner.–
He clearly used the example to justify G&T’s and his claim that planetary radiation balance is inappropriate, not as the simple what if he now claims. If you use appropriate measured values (which I provided links to in #1009) for eps the simple radiation balance model works well and is fully appropriate.
— Posted by Eli Rabett
1034. February 13th, 2008 6:09 am Gerlich and Tscheuschner reply to Lazar
#1025 Lazar writes:
Gerhard Kramm clearly means the (internal) energy of the warmer reservoirs ….
Kramm does not and could not mean the (internal) energy of the warmer reservoirs. The exchange of heat or work are the objects that are studied in thermodynamics, not undefined (internal) energies of reservoirs.
Only the description of a process can be a perpetuum mobile, not an existing process in nature.
Dear Lazar, please study al little bit of logic and physics.
— Posted by Gerhard Gerlich and Ralf D. Tscheuschner
1036. February 13th, 2008 11:59 am and Lazar fires back
#1034 Gerhard Gerlich and Ralf D. Tscheuschner write;
#1025 Lazar writes:
Gerhard Kramm clearly means the (internal) energy of the warmer reservoirs ….
Kramm does not and could not mean the (internal) energy of the warmer reservoirs.
You misquoted me.
Gerhard Kramm clearly means the (internal) energy of the warmer reservoir rises
If that is unclear, the relevant parts of Gerhard Kramm’s statement highlighted in bold:
One first considers the transfer of heat from a colder reservoir to a warmer one so that the latter becomes still warmer (1st step), then in a 2nd step this surplus of heat in the warmer reservoir is transferred to a machine in which it is converted into mechanical work on the basis of the best possible efficiency (that of a Carnot process). The remaining amount of heat is then transferred to the colder reservoir.
G&T;
The exchange of heat or work are the objects that are studied in thermodynamics,
Which depend on the properties of the objects from which they are transferred to and from, such as, internal energy, heat capacity, emissivity…
not undefined (internal) energies of reservoirs.
That an internal energy is undefined has nothing to do with whether it rises.
Dear Lazar, please study al little bit of logic and physics.
I always do.
I suggest you do similar.
— Posted by Lazar
1037. February 13th, 2008 2:04 pm Eli wanders by again
One of the open questions (well it was opened by Kramm in #999) has been why did he use an emissivity of 0.61. One of the anonymice posters at my blog has answered the question
http://rabett.blogspot.com/2008/02/why-it-pays-to-have- clever-anonymice.html
It turns out that this is the “effective emissivity” — ie, that it already includes the influence of the greenhouse effect due to atmosphere and is discussed in the Wikipedia
–This yields an average earth temperature of 288 K [3]. This is because the above equation represents the effective radiative temperature of the Earth (including the clouds and atmosphere). The use of effective emissivity already accounts for the greenhouse effect. (along with clouds and other stuff)–
As the commenter added
– So, in effect, Kramm is trying to “prove” that with no greenhouse effect, the earth would have the same temperature that it actually does by using an effective emissivity that already takes into account the greenhouse effect!–
It’s nice to settle something.
— Posted by Eli Rabett
1039. February 13th, 2008 3:26 pm which Kramm responds to
Re # 1029 and #1009,
here is a simple instance to explain the role of the emissivity. In the literature one can find emissivities for old snow (eps = 0.82) and fresh snow (0.99). If we assume a surface temperature of 270 K the difference in the radiation fluxes emitted by an old snow cover and a fresh snow cover would be 51 W/m^2. This value, for instance, is 20 times larger than the anthropogenic radiative forcing. Consequently, in numerical models of the atmosphere it is indispensable to use formula to reduce the emissivity as a function of time after a snow event.
More than 20 year ago, it was shown that averaging of surface properties like the albedo and emissivity leads to inappropriate results when the exchange of energy between the atmosphere and the underlying vegetation-soil system is simulated for the various grid elements of numerical weather prediction models. Therefore, methods like the small-scale mixture approach (e.g., Deardorff, 1978; Sellers et al., 1986; Kramm et al., 1996), the mosaic approach for the mesoscale (e.g., Avissar and Pielke, 1989; Molders and Raabe, 1996) and sub-grid strategies (e.g., Seth et al., 1994; Molders et al., 1996) were developed to avoid averaging of surface properties. Various versions of the mosaic approach have been established even in recent global climate models.
Consequently, for estimating the greenhouse effect it is indispensable to globally average over the temperatures derived from local radiation balances, but not to use mean values like a planetary albedo and a planetary emissivity and a uniform temperature of a radiative equilibrium for a non-rotating Earth without an atmosphere. This is, indeed, physical nonsense and far behind the knowledge of the scientific community in this matter.
Obviously, many of the so-called climate scientists not educated and trained in the key disciplines (geo)physics, meteorology and physical oceanography have difficulties to recognize these facts.
Sincerely yours
Gerhard Kramm
— Posted by Gerhard Kramm
1042. February 13th, 2008 8:29 pm Lazar makes a point in a sidetrack with Brian Valentine
#1026 Brian Valentine writes;
The third statement is false
please see 893. then if there is still concern that the 2nd law has been interpreted incorrectly by any, I’ll correspond by email.
I have no problem with #893, but that has nothing to do with what Gerlich, Tscheuschner, and Kramm are claiming, that the GHG effect suggests the cooler atmosphere transfers heat to the warmer surface under increasing GHG concentrations, in violation of the second law.
It does not, for reasons gone over tirelesly by Eli and others.
The net energy flow, heat transfer, is the other way around. The surface still cools to the atmosphere.
Note that all three have skirted the issue, G&T now waffling on about whether Kramm ‘really meant’ internal energy, and other games…
They are studiously avoiding other questions.
1043. February 13th, 2008 8:42 pm Kramm tries again
Re # 1037
again, the radiation balance equation,
(1 – a) S/4 = eps sigma T_e^4 ,
is inappropriate to estimate the greenhouse effect. (The symbols are explained in my comment #770, with exception of eps, a planetary emissivity.)
In my comment # 999 I wrote: “If we use a value for eps less than unity, we will obtain an equilibrium temperature T_e higher than 255 K.”
This is absolutely correct, not only from a mathematical point of view, but also from a physical perspective. An emissivity less that unity means that the emission of energy is lower than for eps = 1.
To drastically underline this fact, I further wrote: “For eps = 0.61 the temperature T_e amounts to 288 K. In such a case there would be no greenhouse effect.”
Consequently, eps must be larger than 0.61 so that
the planetary radiation balance can deliver a value less than 288 K. My goodness, this is so simple.
For eps = 0.9, for instance, we would obtain nearly 262 K, i.e., the so-called greenhouse effect would be 26 K, when the planetary albedo is held fixed.
By the way, to discuss a functional relationship between dependent variables and independent variables is the matter of functional analysis. In the case of the planetary radiation balance such a discussion is very simple.
Sincerely yours
Gerhard Kramm
— Posted by Gerhard Kramm
1049. February 14th, 2008 12:47 am which Arthur Smith deconstructs
Gerhard Kramm (#1043, #1039, #1024), are you now claiming that, rather than variation in temperature, variation in thermal emissivity is the explanation for the large observable discrepancy between incoming solar radiation and average temperature on Earth’s surface? You still have not responded to any of my questions on this discrepancy and the inequality relationship between average temperature and insolation that G&T proved (under the assumption of fixed emissivity) - why?
Despite your many comments earlier in this thread, the first time you even brought up the issue of varying emissivity was in #1024. Are you implicitly renouncing all your previous arguments in favor of the varying emissivity explanation?
To be clear - the size of the discrepancy between solar insolation and the minimum energy output from Earth based on the average temperature is some 63% (positive discrepancy relative to the smaller solar number; using the larger Earth surface number as reference gives a negative discrepancy of 39%). But the maximum variation in thermal emissivity across Earth’s various surfaces (from the MODIS link provided in comment #1009) seems to be between about 0.90 and 1.00, or 10%. This variability is far too small to explain a 39% reduction in total emitted energy.
Dr. Kramm, whether it’s variable temperature (which only makes things worse) or variable emissivity (which is just too small to make enough difference), your numbers are not adding up. Please state clearly what exactly it is you’re claiming, because none of the claims I have been able to extract so far from your comments make any sense.
— Posted by Arthur Smith
1052. February 14th, 2008 9:23 am Arthur Smith continues
Thomas Lavin (#1045) - nice analogy, but to be accurate, the 163 watts would have to be measured *inside* the “Greenhouse”, not outside. The same 100 watts you put in of course has to leave the “Greenhouse” in the end. But it can bounce around inside the “Greenhouse” a couple of times first.
For another moderately inappropriate analogy, think of an extension cord with 100 watts running through it. Put a loop in it and you now have 200 watts running in the original direction, and 100 running the other way.
Or for yet another moderately relevant analogy, think of a system of ropes and pulleys. An input force can be greatly increased through use of simple machines of this sort; it’s still the same force going in, the same work expended. When you move your hands 10 feet, the load only moves 1 foot, say, but the force on the load is 10 times the force you are exerting at input.
There are all sorts of multiplicative analogies of this sort in science and engineering. The effect of layers that are transparent to incoming light but absorptive of outgoing IR is yet another example - that’s the atmospheric greenhouse effect that all of climate science is based on, it acts as a multiplier of the initial energy flow from the sun.
But Gerlich and Tscheuschner, and Gerhard Kramm seemingly by supporting them, keep claiming that “the atmospheric greenhouse conjecture is falsified” to quote the abstract of the G&T paper. So I’m trying to get them to answer how they explain the observational discrepancy between incoming sunlight and outgoing thermal radiation from Earth’s surface. So far they have not responded at all to my questions, and seem to want to keep changing the topic.
In brief response to sas (#1044) - far from talking about “how many angels can fit on the head of a pin”, we are trying to get to the bottom of some real science claims that have been made here and elsewhere. Science relies on quantitative statements that relate measurements and observations through solid logic and mathematical analysis. I and others on this thread have been trying to pin down Kramm, Gerlich and Tscheuschner on a precise mathematical statement of what they are claiming for the relationship between incoming solar energy and temperatures on Earth, the essence of the atmospheric greenhouse effect that G&T claim to have “falsified”. Without the precise detail of what they claim, we simply cannot evaluate it for truthfulness, whatever the rhetorical devices used to promote one side or the other.
— Posted by Arthur Smith
Eli has omitted a bit of back and forth btw. Kramm and lazar
1064. February 14th, 2008 7:27 pm Kramm tries to corner Arthur Smith
Re: #1049, 1052
Dear Arthur Smith,
our discussion is focused on the simple planetary radiation balance scheme,
(1 - a) S/4 = eps sigma T_e^4 .
(I explained the symbols in earlier comments.) This scheme is based on a thought experiment of an non-rotating Earth without an atmosphere. Usually, eps is considered as equal to unity, i.e., it is assumed that the Earth acts like a perfect black body. Even in this simple case, one may state that this is not true. It is quite understandable that the so-called greenhouse effect quantified on the basis of this planetary radiation balance scheme depends on both the planetary albedo and the planetary emissivity.
Currently, I am finishing a textbook on micrometeorology. For this reason I gathered a lot of values for albedo and emissivity of several surfaces. For instance: deserts have an albedo ranging from 0.20 to 0.45 and an emissivity ranging from 0.84 to 0.91, snow has an albedo ranging from 0.4 (old snow) to 0.95 (fresh snow) and an emissivity ranging from 0.82 (old snow) to 0.99 (fresh snow). These values are based on direct measurements performed by various authors during field experiments.
In the case of water, for instance, it is important to distinguish between the albedo for small solar zenith angles (0.03 to 0.1) and large solar zenith angles (0.1 to 0.5). Furthermore, the albedo over land depends on the soil moisture content. Dry sand, for instance, has an albedo ranging from 0.35 to 0.45. Whereas that of wet sand is ranging from 0.2 to 0.3. All these values mentioned here are mean values and their uncertainty is usually expressed by standard deviations.
Of course, there are values based on satellite observations. Please read the user’s guides and recognize in which way these values were derived.
Nevertheless, the variation of albedo and emissivity is a minor one. The main problem is that the simple planetary radiation balance scheme listed above is considered to be serious for quantifying the greenhouse effect, even though a equilibrium temperature T_e uniform for the whole globe does not exist. It completely disagrees with our observations, not only in the case of the Moon (covered by a very thin atmosphere), but also in the case of the Earth with an atmosphere. Thus, it is highly unsuitable for quantifying the greenhouse effect, as already analyzed in the paper of Gerlich and Tscheuschner. Ignoring observational evidence is the basis for scientific misconduct and scientific fraud.
Of course, I understand why people are in favor for this simple radiation scheme. They are able to “understand” it. To deal with the radiative transfer equation and the various conservation equations is much more diffcult. However, for quantifying the temperature change by various atmospheric trace constituents it is indispensable to understand the physics formulated in these equations and to be well familiar with vector and tensor calculus. Meteorologists, physical oceanographers, and (geo)physicists are trained in these disciplines. Gerlich, for instance, has written textbooks on vector and tensor calculus and the statistical and mathematical fundamentals of quantum theory.
Please take a look into textbooks on atmospheric dynamics like Riegel (1992), Fundamentals of Atmospheric Dynamics and Thermodynamics, Holton (1992), An Introduction to Dynamic Meteorology, or, my favorite one, Dutton (1995), Dynamics of Atmospheric Motion, and atmospheric radiation like Chandrasekhar (1960), Radiative Transfer, Goody and Yung (1989), Atmospheric Radiation, Lenoble (1993) Atmospheric Radiative Transfer, Liou (2002), An Introduction to Atmospheric Radiation, and Bohren and Clothiaux (2006), Fundamentals of Atmospheric Radiation. I use these textbooks for my courses on atmospheric dynamics and atmospheric radiation. The graduate students who took these classes are well trained in these disciplines.
Sincerely yours
Gerhard Kramm
— Posted by Gerhard Kramm
1066. February 14th, 2008 11:44 pm Smith responds
Dear Dr. Kramm (#1064)
Once again you refuse to put down in mathematical form what it is you are claiming. At least you have now backed off the variable emissivity argument and are apparently returning to your earlier variable temperature one, but you are making very strong claims that are simply not backed up by the facts:
“The main problem is that the simple planetary radiation balance scheme listed above is considered to be serious for quantifying the greenhouse effect, even though a equilibrium temperature T_e uniform for the whole globe does not exist.”
Nobody other than you and G&T has ever claimed the T_e in that equation is referring to some realistic model of a planet (especially not one that is non-rotating!) with a uniform surface temperature. The ‘e’ subscript is referring to an *effective* temperature. The actual definition of T_e in the non-greenhouse case (or the equivalent to describe outgoing thermal energy in a greenhouse case) is as the fourth root of the average of fourth power of temperature across the planet (with appropriate local emissivity factor adjustments for full accuracy). That is because as the right-hand-side of the radiation balance equation in the form you give it, it represents the thermal energy emitted, corresponding to the left-hand side representing incoming solar energy absorbed.
If there is an atmospheric greenhouse effect then that gives a back-radiation factor from the atmosphere that also adds to the left-hand “input” side, raising the effective temperature on the right-hand side. But G&T claim they have “falsified” the atmospheric greenhouse effect, so they are not allowed such additional terms on the left-hand side of the equation. Do you agree with this, or do you believe the greenhouse effect does add additional input energy to the surface of Earth?
Furthermore, contrary to your claims that this “disagrees with our observations”, a number for T_e can in fact be calculated for Earth following this fourth root of the average fourth power approach, and it is only very slightly higher than the observed average temperature of Earth itself. And therefore, for the real Earth the above balance equation cannot hold, because the right hand side is very much larger than the left side. No matter what the distribution of temperatures on the planet, it is a simple matter to prove, and G&T actually do it in their section 3.7, that T_e calculated in this manner is always greater than or equal to the average temperature of the planet.
We have two observable numbers: incoming light energy from the sun, and outgoing thermal energy from Earth’s surface. The outgoing energy is at least 63% greater. If you agree that the G&T argument has “falsified” the atmospheric greenhouse effect, then precisely where is this extra energy coming from? Please answer the question for once, don’t keep sidestepping it!
You continue: “It completely disagrees with our observations, not only in the case of the Moon (covered by a very thin atmosphere), but also in the case of the Earth with an atmosphere.”
Let’s talk about the Moon. There is no greenhouse term there. What do we see? The Bond albedo of the Moon is 0.11, and the Moon’s distance from the Sun is essentially the same as Earth’s, so incoming absorbed solar energy averages to 304 W/m^2. Emissivity is believed to be close to 1, so if the balance equation holds then the Moon’s T_e value should be about 271 K.
What do we observe then on the Moon? Because of its slow rotation, relatively low heat capacity, and low thermal conductivity through the surface materials, temperatures between the day and night sides vary very widely, a range far greater than on Earth. The average day-side temperature hits close to 400 K for noon at the equator while staying closer to 200 K near the poles. On the night side temperature drops to about 120 K near the equator, and is believed to reach close to absolute zero near the poles. Overall average temperature is around 230 K, or well under the 271 K limit set by the radiation balance equation.
To actually calculate the observational T_e value (the fourth root of the average fourth power of temperature) would require a more detailed analysis of the Moon’s temperature distribution than I happen to have; the rough numbers I do have give 280 K plus or minus 20 K or so, so perfectly within the region expected, even despite the very wide range in observed temperatures.
So, as one would expect, the radiation balance equation fits perfectly with the situation on the Moon, where there is definitely no atmospheric greenhouse effect!
So, please explain, other than the varying temperature distribution, which I have already repeatedly agreed with you on, how the relationship “completely disagrees with our observations”!
Then you go on, “Thus, it is highly unsuitable for quantifying the greenhouse effect, as already analyzed in the paper of Gerlich and Tscheuschner.”
To the contrary, comparing total incoming energy from the sun with total outgoing thermal energy from the surface, which is what you get from comparing the two sides of this equation, is the *only* way to quantify the greenhouse effect. The lack of radiation balance for Earth with this simple equation is the primary reason we know the greenhouse effect exists, and how large it is. Specifically, it adds about 63% to the energy available to Earth’s surface, above and beyond the direct input from the sun. In temperature terms, that means a difference of at least 33K. G&T have not “falsified this”; despite the words they use, their equations only prove that temperature variability on a real planet makes the discrepancy in radiation balance even more significant, if you leave out the greenhouse effect.
“Ignoring observational evidence is the basis for scientific misconduct and scientific fraud.”
I am almost at a loss for words on this one. Those are very strong claims. Please state your case clearly and precisely; I still see no statement from you of exactly how you believe the “greenhouse effect is falsified” that resolves the observational evidence of a large discrepancy between incoming solar energy and outgoing thermal surface energy. I hope you have something real behind such strong words, Dr. Kramm.
— Posted by Arthur Smith
1067. February 14th, 2008 11:52 pm and Eli comes up with a simple model
Let Eli describe a simple experiment. Take two large disks with emissivities of unity, one at temperature T1 the other at T2, the second being higher than the first. For convenience assume they only have one side
Place each in turn in empty space. Both will radiate their energy away cooling. Neither convection or conduction can occur. Radiation will
Place them directly opposite each other with a perfect vacuum in between. Still no convection or conduction
The net radiative energy flow will be from the hotter to the colder, HOWEVER, the colder object also radiates. That radiation impinges on and is absorbed by the warmer disk. It “warms” the hotter one or put otherwise, it slows the cooling of the warmer body.
According to KG&T this is wrong. But if no radiation can be emitted from the colder body and be absorbed by the warmer one, somehow the colder body’s radiation is turned off by the presence of the warmer body. Is this perhaps IT (Intelligent Thermodynamics)? Eli doubts it.
1068. February 15th, 2008 12:10 am Chris Colose joins in
Gerhard Kramm
the “falsification” paper by Gerlich was a science fiction puff piece. Perhaps Dr. Pierrehumbert’s insisitence on a publication record is not convincing, but there is a reason why that was not peer reviewed, and will not in fact revolutionaize anything in science, change the textbooks, change classroom lectures, or give two people a nobel– because it was garbage. In fact the tone of the paper itself was worth dismissing. Before anyone so ignorant in the matter starts to write papers or textbooks, I suggest they read one, starting with Raymond Pierrehumbert’s “Principles of Planetary Climate” or maybe David Archer’s, or perhaps a wikipedia article…
For a more visual formula, for those who do not in fact understand emissivity (or when it already includes the greenhouse effect), try this one
S/4 (1-a) + G = sig T^4 where G is the greenhouse effect at 150 W/m^2. That is, a 150 W/m^2 that has apparently gone missing from the surface to the TOA without explanation. See Eli’s blog for more destruction of this nonsense, or mine for basic understanding.
— Posted by Chris Colose
1069. February 15th, 2008 7:59 am Arthur Smith RTFR
One more thing for Gerhard Kramm (#1064). You refer to a number of books at the end of your comment. I looked up one: Liou (2002), An Introduction to Atmospheric Radiation. Section 4.1 is titled “The Thermal Infrared Specrtum and the Greenhouse Effect”. On page 118 is written:
“The trapping of thermal infrared radiation by atmospheric gases is typical of the atmosphere and is therefore called the atmospheric effect. It is also referred to as the greenhouse effect […]” and the text goes on to discuss the difference between effective temperature in the radiation balance sense and the observed average surface temperature as we have been talking about here.
I have little doubt that most of the other books you referred to also similarly correctly describe the atmospheric greenhouse effect, which Gerlich and Tscheuschner claim to have “falsified”.
Dr. Kramm - who do you say is right: Liou and the other authorities who have written these textbooks, or Gerlich and Tscheuschner who claim the opposite? It is logically impossible to say two contradictory claims are both correct. Please pick one.
— Posted by Arthur Smith
1070. February 15th, 2008 9:36 am Lazar comments:
#1067 Eli Rabett writes;
“The net radiative energy flow will be from the hotter to the colder, HOWEVER, the colder object also radiates. That radiation impinges on and is absorbed by the warmer disk. It “warms” the hotter one or put otherwise, it slows the cooling of the warmer body.
According to KG&T this is wrong. But if no radiation can be emitted from the colder body and be absorbed by the warmer one, somehow the colder body’s radiation is turned off by the presence of the warmer body. Is this perhaps IT (Intelligent Thermodynamics)? Eli doubts it.
He rather prefers that KG&T are blowing smoke.”
G&T make a pretence of addressing these issues in section 3.9.3 of “Falsification Of The Atmospheric CO2 Greenhouse Effect”, where they respond to the following comment by Stefan Rhamstorf;
“Some `sceptics’ state that the greenhouse effect cannot work since (according to the second law of thermodynamics) no radiative energy can be transferred from a colder body (the atmosphere) to a warmer one (the surface). However, the second law is not violated by the greenhouse effect, of course, since, during the radiative exchange, in both directions the net energy flows from the warmth to the cold.”
… with the following;
“Rahmstorf’s reference to the second law of thermodynamics is plainly wrong. The second law is a statement about heat, not about energy. Furthermore the author introduces an obscure notion of “net energy flow”. The relevant quantity is the “net heat flow”, which, of course, is the sum of the upward and the downward heat flow within a fixed system, here the atmospheric system. It is inadmissible to apply the second law for the upward and downward heat separately redefining the thermodynamic system on the fly.”
I pointed out elsewhere that the above is tangential, and in some places wrong, in others not even wrong (meaningless).
They elsewhere responded with a non-sequiter, claiming heat cannot be a measure of net energy transfer because it is described by the field form; q = -(lambda) grad T.
“In thermodynamics the exchange of heat is described with a differential form, the heat form (for instance in a temperature,volume manifold). It is not a (net) flow of energy. It is not an exact (closed) differential form. Irreversible thermodynamics is a field theory, then you have to use a temperature field, entropy densities, densities of heat, densities of internal energy and so on (compare preprint pages 81ff).”
Nonsense. Heat being a measure of the net energy transferred by thermal mechanisms (conduction, convection, radiation) between regions in thermal contact, is not altered by the fact that it depends on the temperature gradient. At equilibrium the temperature gradient is zero, the net energy transfer is zero, and energy is still being transferred by the above mechanisms.
And more smoke… in sections 3.9.1, 3.9.2 and 3.9.3 of their manuscript, G&T happily described heat (as you and I have done) in the context of the second law and GHG effect as a one-dimensional vector, but now they insist heat must be represented by a three dimensional vector field with spatial variation within a volume manifold (q = -(lambda) grad T).
And finally, in their response to Rhamstorf, “The second law is a statement about heat, not about energy. Furthermore the author introduces an obscure notion of “net energy flow”. The relevant quantity is the “net heat flow”", we are introduced to a mysterious new substance, measured in joules, that is not energy.
Do they think no one can follow?
— Posted by Lazar
1074. February 15th, 2008 6:33 pm Lazar continues:
Ding! I think I see what they’re doing here…
“Furthermore the author introduces an obscure notion of “net energy flow”. The relevant quantity is the “net heat flow”, which, of course, is the sum of the upward and the downward heat flow within a fixed system, here the atmospheric system.”
They’re defining the Q in the first law [delta]E = Q - W as the net heat transfer due to radiation, convection and conduction.
Which is fine, except when it comes to the second law, they’re not using Q, just heat, which they’ve previously defined as a one-way (gross) transfer of thermal energy.
So, in the second law ‘heat cannot be transferred from a cooler body to a warmer body without input of energy by work’, heat is not Q, heat is a one-way transfer of thermal energy, which then implies ‘the warmer surface cannot receive radiation energy from the cooler atmosphere’.
Gerhard Kramm essentially admits Eli’s example in #1067;
“the tendency to a radiative equilibrium means that the emitter with the higher surface temperature will loose energy due to a negative net radiation balance until this net radiation balance becomes zero.”
Even G&T apparently do;
“The theoretical black body absorbs - by definition - all radiation [including radiation emitted from cooler bodies — Lazar]. We never tried to change this.”
In which case, they’ve falsified the second law. Well done!
— Posted by Lazar
1075. February 15th, 2008 7:17 pm Kramm doesn't see the trap that Arthur Smith has constructed
Re: #1066
Dear Arthur Smith,
the temperature distribution for the Moon listed in your comment is close to that I found in one of my handbooks on astrophysics. Therefore, I use the temperatures at the poles (nearly 200 K) and the equator (nearly 400K) to explain the difference between averaging the temperatures and averaging the emission values to estimate a representative temperature for this mean emission.
Averaging the temperatures leads to a mean temperature of 300 K. Averaging the emission values yields 341 K.
This means that using a uniform temperature, T_e, for the whole globe is inappropriate. We have to consider the local radiation budget which is not equal to zero when, in addition, a ground heat flux occurs like in the case of a rotating planet without an atmosphere. Since, generally, the solar irradiance reaching the surface of such a planet depends on both the longitude (day-night variation) and the latitude (variation of the solar zenith angle), it is indispensable to consider the local radiation budget.
I do not understand that this requirement is so heavily disputed here because in any numerical model of the atmosphere the lower boundary conditions are predicted on the basis of such energy budget equations (usually the fluxes of sensible and latent heat are included, too). The radiation budget is a part of them.
To ignore observational evidence is, indeed, the basis, at least, for scientific misconduct.
Here is a typical example. In 2001 there was a paper in Science in which the Nenana Ice Classics plaid a role. The authors used the data of the break-up of the Tanana River at Nenana/Alaska from 1949 to 2000 as proxy data to identify the effect of global warming. As documented by the late John Daly, a retired sea officer, the authors completely ignored the data from the beginning in 1917 to 1948. Including these data yields appreciably different results (http://www.john-daly.com/nenana.htm ).
To check Daly’s results I downloaded the complete data set of the ice break-up from the homepage of the Nenana Ice Classics. There was no difficulty. By the way, John Daly’s results are correct.
Two questions: Why did the authors only consider a part of these data? And why did they start in a rather cold year? I have no answer. However, I must assume that the complete data set did not satisfy their agenda. There are several of such instances.
Sincerely yours
Gerhard Kramm
— Posted by Gerhard Kramm
1076. February 15th, 2008 7:53 pm Kramm tries to dissociate himself from his own source
Re: #1069
Dear Arthur Smith,
your quotation “The trapping of thermal infrared radiation by atmospheric gases is typical of the atmosphere and is therefore called the atmospheric effect. It is also referred to as the greenhouse effect” is correct.
I do not agree with Liou’s statements. Infrared radiation emitted by the earth’s surface is not trapped. It is absorbed and emitted by the so-called greenhouse gases. Furthermore, a temperature change is not related to the magnitude of the radiation flux, but to its divergence. These are quite different things.
As a teacher in science it is indispensable to use more than one textbook. Even in excellent textbooks there are typing errors, misinterpretations etc. It is the teacher’s responsibility to avoid such weak points. Please read also the textbook of Bohren & Clothiaux (2006), Fundamentals of Atmospheric Radiation. I think that they appreciably disagree with Liou in this matter.
Nevertheless, if there are different opinions in textbooks, it is indispensable to discuss them with the students.
Sincerely yours
Gerhard Kramm
— Posted by Gerhard Kramm
1077. February 15th, 2008 8:15 pm Kramm continues
Re: #1071
Dear Lazar,
in a reply to your comments #844 and #865 I stated:
“In your comment #844 you quoted: “As an object radiates energy at a rate given by Equation 20.18 [P = o A e T^4], it also absorbs electromagnetic radiation. If the latter process did not occur, an object would eventually radiate all its energy, and its temperature would reach absolute zero [this is before the quantum mechanics section]. The energy an object absorbs comes from its surroundings, which consists of other objects thar radiate energy. If an object is at temperature T and its surroundings are at a temperature T[0], then the net energy gained or lost each second by the object as a result of radiation is P[net] = o A e (T^4 - T[0]^4). When an object is in equilibrium with its surroundings, it radiates and absorbs energy at the same rate, and so its temperature remains constant. When an object is hotter than its surroundings, it radiates more energy than it absorbs, and its temperature decreases.”
I substantially agree with this quotation. It clearly states that (a) emission of energy by radiation is accompanied with cooling of the surface (if no compensating changes prevent it), and (b) the tendency to a radiative equilibrium means that the emitter with the higher surface temperature will loose energy due to a negative net radiation balance until this net radiation balance becomes zero. This also means that its surface temperature decreases and approaches the equilibrium temperature. However, it does not mean that both the temperature of the cooler emitter and the temperature of the hotter emitter rise to higher values.”
Please quote me correctly.
Sincerely yours
Gerhard Kramm
— Posted by Gerhard Kramm
1078. February 15th, 2008 8:53 pm Kramm tries to get Arthur Smith to do his bidding
Re: #1069
Dear Arthur Smith,
there is an interesting two-layer radiative equilibrium scheme in Liou’s textbook (see page 461). Please perform some calculations with the solution (8.3.5) and (8.3.6). (This solution is absolutely correct.) If the value for the absorptivity in the solar spectrum is equal to zero, the calculated temperature of the Earth’s surface will be too high, compared with the globally mean near-surface temperature.
Sincerely yours
Gerhard Kramm
— Posted by Gerhard Kramm
1080. February 15th, 2008 11:15 pm Smith replies to 1078
Gerhard Kramm,
you keep talking about the need to rely on observation on the one hand, but then go on about models on the other. I think I’m beginning to see that your continual discussion of the “local radiation balance” and “local radiation budget” is because you are viewing this as some sort of modeling problem. You even get specific in #1075: “in any numerical model of the atmosphere the lower boundary conditions are predicted on the basis of such energy budget equations”.
Yes, all that is absolutely true if you are trying to predict the temperatures on a planet based on incoming radiation and the other physical processes going on. That’s what climate models do.
But the central issue here, the one which Gerlich and Tscheuschner talk about, has nothing to do with climate modeling. It is a comparison of two physical observations: incoming solar radiation, and the observed temperatures of the Earth. There is a discrepancy relative to the absolute mathematical relationship that must exist between these quantities, irrespective of any model: the temperatures are too high. You continue to refuse to answer my questions about what you believe the source of this discrepancy to be, what it even possibly could be if it is not the greenhouse effect.
The closest you have come to an answer is your commentary (#1075): “I do not agree with Liou’s statements. Infrared radiation emitted by the earth’s surface is not trapped. It is absorbed and emitted by the so-called greenhouse gases.” Yet that sounds like selective parsing of meaning rather than a real argument. What could Liou have possibly meant by trapping other than absorption and emission? Do you, along with G&T, dispute the fundamental atmospheric greenhouse effect that acts to multiply incoming solar energy at Earth’s surface?
But it is pointless to go on if you refuse to answer such basic yes or no questions. You seem to want to have it all different possible ways: G&T are right, but the Lious and other established scientists of the world are of course right too.
Well, I’m sorry, if Liou is right in any way about the behavior of the atmosphere, then Gerlich and Tscheuschner’s argument is completely wrong.
Either that or they have been completely misinterpreted. But I find it hard to credit anything somebody has to contribute who says “the atmospheric greenhouse effect is falsified” if they didn’t really intend to claim there is no greenhouse effect.
— Posted by Arthur Smith
1082. February 16th, 2008 5:50 am Lazar narrows the argument:
#1077 Gerhard Kramm writes;
Please quote me correctly.
Could you explain what relevance the additional material has?
Ok, let’s try again.
You write;
I substantially agree with this quotation. It clearly states that (a) emission of energy by radiation is accompanied with cooling of the surface (if no compensating changes prevent it), and (b) the tendency to a radiative equilibrium means that the emitter with the higher surface temperature will loose energy due to a negative net radiation balance until this net radiation balance becomes zero.
Do you agree that radiative transfer occurs in both directions in the above case (you imply this when you write “negative net radiation balance” and “I substantially agree with the above quotation”)?
If yes, do you agree that the transfer of energy (heat) by radiation from the cooler body to the warmer body does not violate the second law — “heat cannot be transferred from one reservoir to another reservoir at a higher temperature - without expending (mechanical) work”, which you applied to the GHG effect as follows; “do you believe that the tropopause region for which the anthropogenic radiative forcing is calculated can warm the nearly 65 K warmer Earth’s surface without any compensating changes?”?
If yes, do you agree that the second law applies in fact to the “net radiation balance” as you put it, that is, the second law would be violated if the “net radiation balance” was positive from the perspective of the warmer body / a net energy (heat) transfer from the cooler body to the warmer?
Do you agree that the net radiative transfer, and indeed the net energy transfer, under conditions of the GHG effect is from the warmer surface to the cooler atmosphere?
Do you agree that under the GHG effect, the surface does not heat due to a second-law violating positive net radiation balance?
Therefore do you accept that the second law is not violated in the case of the GHG effect?
If not, why not?
— Posted by Lazar
1083. February 16th, 2008 12:03 pm Lazar continues:
#1077 Gerhard Kramm, I think I see what you’re getting at…
“I substantially agree with this quotation. It clearly states that (a) emission of energy by radiation is accompanied with cooling of the surface (if no compensating changes prevent it), and (b) the tendency to a radiative equilibrium means that the emitter with the higher surface temperature will loose energy due to a negative net radiation balance until this net radiation balance becomes zero. This also means that its surface temperature decreases and approaches the equilibrium temperature. However, it does not mean that both the temperature of the cooler emitter and the temperature of the hotter emitter rise to higher values.”
In fact the last (bold part) does not violate the second law. All the second law states is that the net energy flow is from the warmer body to the cooler, it does not state anything regarding temperature changes of the two bodies. Of course the temperature of the warmer body decreases and the cooler body rises under the above scenario, anything other is unphysical (there is no physical reason for it), provided you have given all the relevant infomation. If there is a third source of energy, the temperature of the warmer body can rise. Now, in the GHG effect there is a third source of energy, and in the enhanced GHG effect we are changing the composition of the cooler body, and therefore the radiative properties, and from that the net energy (heat) balance. The appropriate atmospheric analogy to your and my example (two approximately black bodies interacting through radiative exchange, the net radiative transfer from warmer to cooler) is a sun-surface-atmosphere system in equilibrium with GHG concentrations held constant, at which point the temperature of the must surface remain constant, and the net energy (heat) flow is from the surface to the atmosphere. A sudden increase of surface temperature outside the bounds of natural variability would then be unphysical. By changing the radiative properties of the atmosphere by increasing GHG concentrations, such that the net energy (heat) flow from the surface to the atmosphere decreases, then under constant input of energy from the sun of course the surface temperature will increase, we fundamentally changed the cooler body, the sun-earth-atmosphere system will seek a different equilibrium. But this is entirely a different situation from your and my analogy where you just have two unchanging bodies interacting.
If you still think the GHG effect violates the second law, please explain how, describing in detail how the sun-earth-atmosphere system interacts through energy exchange and how this violates the second law.
Either way, please state whether you agree or disagree.
Otherwise, this is my final comment on the issue or I will bore everyone to death.
— Posted by Lazar
1086. February 16th, 2008 9:27 pm Kramm still does not see where Arthur Smith is going
Re: #1080
Dear Arthur Smith,
I beg your pardon, but I disagree with you. In the literature, this simple planetary radiation balance scheme of a non-rotating Earth without an atmosphere (I denoted it a thought experiment) is often called a zero-dimensional climate model. This means that a comparison with General Circulation Models (GCMs), in which a radiation budget is determined for any grid element, must be allowed.
If we try to determine a temperature distribution for a planet without an atmosphere, we have to apply procedures analogous to those used in GCMs. From such a temperature distribution one may derive a mean global surface temperature and may compare it with the globally average near-surface temperature for the real Earth-atmosphere system of about 288 K. If a difference between these two globally averaged temperatures occurs, this might be denoted as the effect caused by the atmosphere. This effect, of course, comprises all energy conversion processes taking place within the atmosphere.
This simple planetary radiation balance scheme only provides a house number, nothing more. From a physical point of view, it is rather unsuitable. In principle, this is what Gerlich and Tscheuschner claimed in their section 3.7. These authors tried to explained it on the basis of the different averaging processes, but obviously their explanation is too high for many climate scientists.
Here, I gained a similar experience when I used a planetary emissivity of eps = 0.61 to point out that this is the lower limit for eps in providing temperatures lower than or equal to 288 K, the current value of the globally averaged near-surface temperature. Meanwhile, Eli Rabett and his disciples speculate whether I took this value from the Wikipedia or not. My goodness, this value is based on the power law of Stefan and Boltzmann and simple algebra.
Sincerely yours
Gerhard Kramm
— Posted by Gerhard Kramm
1088. February 17th, 2008 12:09 pm Gerlich and Tscheuschner still are trying (very)
Response to #1036 and #1071 (Posted by Lazar)
Lazar -
We did not misquote you (c.f. the dots). The words which the dots stand for are irrelevant here. Therefore your statement is a lie.
You characterize the following text published at
http://cjunk.blogspot.com/2008/01/german-hysicists-disp rove-grenhouse.html
as nonsense
(text was quoted in #1071, the phrase in […] has been added afterwards):
“In thermodynamics the exchange of heat is described with a differential form, the heat form (for instance in a temperature volume manifold). It is not a (net) flow of energy. It [exchange of heat] is not an exact (closed) differential form. Irreversible thermodynamics is a field theory, then you have to use a temperature field, entropy densities, densities of heat, densities of internal energy and so on (compare preprint pages 81 ff.).”
But this is standard textbook knowledge.
— Posted by Gerhard Gerlich and Ralf D. Tscheuschner
1091. February 17th, 2008 7:12 pm Lazar is not accepting delivery
#1088 Gerhard Gerlich and Ralf D. Tscheuschner write;
“We did not misquote you (c.f. the dots). The words which the dots stand for are irrelevant here. Therefore your statement is a lie.”
Please see wiki for definitions of misquote.
It was not just the dots. You misquote me by attributing to me words and a statement which I did not write, and you thereby made the statement appear more vague than it was.
You claim;
“#1025 Lazar writes:
Gerhard Kramm clearly means the (internal) energy of the warmer reservoirs …”
by which it seems I was accusing Gerhard Kramm of referring solely to absolute values of internal energies of warmer reservoirs, and having erected that strawman, you proceed to knock it down by claiming such absolute values are undefined;
“Kramm does not and could not mean the (internal) energy of the warmer reservoirs. The exchange of heat or work are the objects that are studied in thermodynamics, not undefined (internal) energies of reservoirs.”
Of course it was the exchange of heat to which I was referring in the statement I actually wrote;
“Gerhard Kramm clearly means the (internal) energy of the warmer reservoir rises”
Which you distort by putting an s on the end of “reservoir” and omit “rises”.
I can follow.
You’d better be damn sure before accusing me of lying.
Anyone can go and check my comment #1036 and verify. They may also note which parts you forgot to respond to.
G&T continue;
“You characterize the following text published at
http://cjunk.blogspot.com/2008/01/german-hysicists-disp rove-grenhouse.html
as nonsense
(text was quoted in #1071, the phrase in […] has been added afterwards):
“In thermodynamics the exchange of heat is described with a differential form, the heat form (for instance in a temperature volume manifold). It is not a (net) flow of energy. It [exchange of heat] is not an exact (closed) differential form. Irreversible thermodynamics is a field theory, then you have to use a temperature field, entropy densities, densities of heat, densities of internal energy and so on (compare preprint pages 81 ff.).”
But this is standard textbook knowledge.”
I did not “characterize the following [preceding] text” as nonsense, as anyone can verify by reading comment #1071. The “nonsense” claim refers to a small part, now highlighted in bold, which indeed is errant nonsense, and the rest is textbook knowledge.
In figure 31 of your paper, you illustrate the second law (of thermodynamics) by showing “heat transfer” as a one-dimensional vector between a higher temperature reservoir and a lower temperature reservoir. You state the second law;
“Any machine which transfers heat from a low temperature reservoir to a high temperature reservoir without external work applied cannot exist: A perpetuum mobile of the second kind is impossible.”
Then can you answer the following straightforward questions (questions which Gerhard Kramm won’t answer);
How is “heat transfer” being accounted for;
Is “heat transfer” calculated as the gross transfer of thermal energy (by conduction, convection and radiation) from the lower temperature reservoir to the higher temperature reservoir?
Or is it the net transfer, the thermal energy transferred from the lower temperature reservoir to the higher temperature reservoir, minus the thermal energy transferred from the higher to the lower?
If it is the latter, then in which direction is the net radiative transfer under the GHG effect?
But if it is the former, then please try explaining Eli’s example #1067.
Now, going back to your claim heat cannot be a net transfer of energy because of, of all things, the fact that heat flux can be expressed in the field form, Fourier’s law, well I responded to that in the original comment (the part you forgot to respond to);
“Heat being a measure of the net energy transferred by thermal mechanisms (conduction, convection, radiation) between regions in thermal contact, is not altered by the fact that it depends on the temperature gradient. At equilibrium the temperature gradient is zero, the net energy transfer is zero, and energy is still being transferred by the above mechanisms.”
Or do you really claim that when two regions in thermal contact are at the same temperature, that no energy exchange by conduction, convection or radiation is occuring?
Considering all that has been written, even in the two comments you address, how about responding to some of Arthur Smith’s or Eli’s points?
— Posted by Lazar
1094. February 17th, 2008 10:21 pm Arthur Smith springs the trap door he tested in 1010
Dr. Kramm, you seem to be starting to get the point I’ve been driving at, though you’re still missing one critical piece. Let me quote an entire paragraph from your comment #1086, because it’s almost right:
“If we try to determine a temperature distribution for a planet without an atmosphere, we have to apply procedures analogous to those used in GCMs. From such a temperature distribution one may derive a mean global surface temperature and may compare it with the globally average near-surface temperature for the real Earth-atmosphere system of about 288 K. If a difference between these two globally averaged temperatures occurs, this might be denoted as the effect caused by the atmosphere. This effect, of course, comprises all energy conversion processes taking place within the atmosphere.”
What you are still missing here is that no matter what model you use, when you have no atmosphere, you will end up with a global average temperature of 255 K or less. There is no atmosphere-free model of Earth, given its observed albedo and surface emissivity values and solar irradiance, that can possibly produce a higher temperature, under steady-state conditions.
The fundamental reason for this is that, without an atmosphere, the absorbed radiation from the sun all reaches the surface of the planet, and the emitted thermal radiation from the surface all reaches space. If the planet is not in the process of warming up or cooling down, those two radiated energies, on average integrated over the planetary surface, must be equal.
So, given the Stefan-Boltzmann law (with whatever tweaks for emissivity are legitimate), the average value of the fourth power of the temperature across this atmosphere-free planet is fixed, if incoming solar radiation is fixed. The fourth root of that average value is the effective temperature, 255 K. And G&T pointed out that that effective temperature is always greater than the actual average temperature of the planet.
This inequality condition is exactly what G&T are showing with their discussion of different kinds of averages in section 3.7. But the logical conclusion seems to be one you three have missed: the Earth’s surface is too hot, compared to any comparable model without an atmosphere. By, not coincidentally, at least 33 degrees C.
If G&T had proved otherwise, they would have shown a model with a higher average temperature than 255 K. To the contrary, the only example they actually calculated had an average temperature far lower. That is only to be expected.
In fact you can create physically realistic model atmosphere-free Earths that have average temperatures ranging anywhere from as close to absolute zero as you want (a planet with zero temperature everywhere except in one spot) all the way up to 255 K (a planet with near-uniform temperatures) for the given average incoming absorbed solar energy. All you have to do is tweak the distribution of incoming energy across the planet; fiddling with heat capacity and rotation rates or thermal conductivity or covering the planet with a material with an appropriately tuned phase transition can also do it.
But there is NO such model that can produce an average temperature higher than 255 K. Given that Earth’s average is observed at 288 K, there is a fundamental discrepancy. That discrepancy is irrefutable proof of the atmospheric greenhouse effect. G&T, if they have made any contribution to understanding here, have only made that assertion more mathematically sound. Too bad they didn’t recognize what their own equations were telling them.
— Posted by Arthur Smith
Good stuff.
ReplyDeleteI found the discussion informative and accessible, and I think most people will. It is also plain to see who is dodging and weaving.
One piece of verbiage stuck, magnetohydrodynamics, which G&T reference but do not quantify.
I wondered how it could apply,
... in the ionosphere, which I understood has about zero influence on tropospheric climate?
... in the oceans, where the effect is barely detectable?
Is there any way there could be a discernible influence on climate (genuine question)? Since G&T dismiss five decades of research with this, I assume it must be a really important effect.
For the record;
"The right side of (Equation 4-10) [Fourier's law along one direction -- Lazar] is the net heat flow out of a slab of thickness (delta)y, per unit time and per unit area. It is nonzero only where there is a curvature in the temperature profile."
Geodynamics, page 139, Turcotte and Schubert.
I really don't understand why some people find this difficult.
How can such people expect to be taken seriously after coming out with obvious crap like that?
ReplyDeleteHow can someone hold a doctorate with such a low level of knowledge?
Don't they have any sense of self preservation?
It is mind boggling.
Sometimes it feels like if we are slipping back to the middle ages, when people embrace such loony theories.
I know that this may seem petty to some and I really don't mean it as such, but I find it amazing that when G&T supply a link they
ReplyDelete1) misspell physicist (forgot the P)
2) misspell greenhouse (double e).
I can see the extra space creeping in through a line-break or something like that. But the others are strange. Drs G&T, if you are reading this, I recommend copy and paste. Simple emacs commands still work on most computers.
Regards
John Cross
So, one way of evaluating professors is what becomes of their graduate students. Has anyone looked into this?
ReplyDeleteWow! It took me minutes and minutes simply to scroll down to here!
ReplyDeleteI'm exhausted from holding down the left mouse button.
(No insult to left mice intended.)
I have been reading the discussion there as it unfolded, very interesting to read. It was great to see so many famous and infamous people appear in the comments as the days went by. I felt like an amateur football player who watching their first professional game live. I decided not to wander onto the pitch.
ReplyDeleteIt was apparent quite early on that kramm was dodging rather a lot under the pressure, hiding his weak position inside a lot of unnecessary detail (much like the G&R paper really, which does for the greenhouse effect what the Beck paper does for co2 rise attribution). I find many internet contrarians simply view the G&R paper as an opportunity to deny something they didn't think of denying previously.
But now that some run-of-the-mill contrarians are jumping in it surely marks a decent into the amateur league. Specifically I saw a Tilo and Kim pushing the contrarian fashions-of-the-month
(GISS fraud, Hansen, cooling, surfacestations, climateaudit) so seeing as im a run-of-the-mill "alarmist", I decided to jump in too. Not trying to change their minds, just practicing on them, trying to find an optimal counter-strategy.
My problem was always that I could never remember precise equations and such, and therefore was always relearning basic stuff thru my calc and phys courses.
ReplyDeleteAfter a while, one can only give up.
But when one is forecasting weather for people whose lives depended on you being right (which I did), two basic rules at the mesoscale applied: hot to cold, high to low.
The basic deconstruction here, Eli, is that these folk highlighted by you disagreed with high to low, hot to cold. I only wish I could deconstruct the arguments as Arthur Smith did. Altho I appreciate the fact theat poor George Smith mentions me, his nemesis, who remembers enough to know he's full of sh*t as does Arthur Smith, who remembers way better than me.
The takeaway? It doesn't take much to see the bullsh*t - rudimentary maths or rudimentary liberal arts. The rhetoric used to hide and dissemble was enough for me, but the insistence that hot doesn't go to cold was the key.
There is ever more clear a distinction here. If we wish for cogent argumentation, we must have the Arthur Smiths and the less convincing Ray Ps (one more rhetoric class would do). We must also have the...middlemen to translate that out for Pareto's 80%.
We're not there yet.
Best,
D
Its a sort of giant red herring isn't it? Everyone knows the so called greenhouse effect is real, and its rough size. This is not the issue.
ReplyDeleteThe issue is how much warming a doubling of the CO2 levels from roughly 300ppm to roughly 600ppm will have, and how much of it is due to the greenhouse effect, and how much of it is due to feedbacks from the greenhouse warming.
And what the evidence is for the existence of the feedback loops.
We don't need any evidence for the greenhouse warming, that's physics, we know that is real. We do need evidence on feedbacks both positive and negative. That's a question about how the engine was designed and constructed.
Put it like this, if we found feedback loops on balance negative, we would not repeal any of the laws of physics. If we found no greenhouse effect, we would.
anonanon
Eli, I suggest you put most of the post body under a "more..." or "read the rest" link, don't know how you do it in blogger but there must be a way?
ReplyDeleteAny help?
ReplyDeleteHide text
Recent comments
Cymraeg llygoden
anonymous anonanon,
ReplyDeleteGerhard Gerlich and Ralf Tscheuschner take the idea a bit farther than just "extra CO2 will not cause warming." They extend the notion to the idea that there is no "greenhouse effect" effect, the delta T of an atmosphere vs. no atmosphere = 33 K is groundless, no real global temperature, and a whole long list of other things that would revolutionize a lot of science.
My comment in Eli's post about this being a "science fiction puff piece" may have been an understatement in retrospect, and I find no way to believe that any respectable and honest scientist could be this ignorant-- even one without sufficient expertise in climate.
What is worth discussing about this piece, rather than just its errors, are its countless strawman attacks. For example, the piece goes to great lengths to show how the idea of an atmsopheric greenhouse is untenable because it does not work like a real greenhouse (i.e., a greenhouse suppresses convection, not so much radiation). This is true (the greenhouse effect in the atmosphere works as a radiative blanket, not a convective one) but that is an analogy-- the comparison is not some physical argument which proves the greenhosue effect in itself. Saying the analogy breaks down somewhere is pointless.
This one was an interesting line in the paper:
"Another movie was shown recently on Channel 4 (UK) entitled \The great global warming
swindle" supporting the thesis that the supposed CO2 induced anthropogenic global
warming has no scientic basis [119]."
What was even more interesting was the section on a "housewife vs. IPCC" where a pot of boiling water is supposed to disprove the greenhouse effect-- the idea goes that the bottom of the pan would be hotter with no water, and colder with water-- so this disproves back-radiation from the greenhouse H20.
Silliness.
Dano, my problem is that my maths isnt very good, but my understanding using words is very high.
ReplyDeleteThe issue with G&T is that they can snowball enough normal people that do not know maths or thermodynamics very well, and thus confuse the issue, as you know. I think that the evidence on the internet is that many people are too mathematically illiterate so that even with the dissembling and fetiliser spreading many normal poeple would be taken in, and by normal I mean those up to and including university level education.
Myself, Slioch and others count as the middlemen/ women who understand enough to translate the scientists speak into analogies and explain things again and again. All over the world there are unrecognised people arguing for the science, and against the idiots.
By the way, thanks to Arthur Smith and Eli Rabett for their educative efforts. This is what makes the internet great, free, as in beer, education from people who know their stuff.
ReplyDeleteI wound him up a bit, but thanks too to Gerhard Kramm, whose engagement was far more substantive than G&T's, and which at least allowed us to understand the flaws in their arguments.
... it was in the year 2050, on a globe an average 1.5 deg C warmer, Gerlich and Tscheuschner put the finishing touches to the 119 page chapter "electrons don't really orbit a nucleus" of "falsification of the universe", and coincidentally the IPCC released the 14th assessment report.
ReplyDelete"You didn't listen, so we built a spaceship. So long, and thanks for all the grants", the authors set out to build a lunar colony established on principles of climatology and of free beer.
Various Republican senators called the enterprise a "communist" affair, from a harem in Riyadh, issued a press release demanding an inquiry into the "extravagant waste of tax payer's money", founded on "alarmism" and "misplaced notions of external reality".
chris colose,
ReplyDelete“For example, the piece goes to great lengths to show how the idea of an atmsopheric greenhouse is untenable because it does not work like a real greenhouse (i.e., a greenhouse suppresses convection, not so much radiation)."
I’m constantly flabergasted by people buying into the “suppresses convection” bit. Yes, convection is suppressed by covrings, but the heating from the re-radiation or “reflection” of longwave energy by most grenhouse coverings needs to be experienced. I earn my rice and beans with a greenhouse. Cooling the sucker is the “climate problem", even changing the entire air volume every minute. I have lots of people stop in when there is snow on the ground, showing no sign of melt, while I have the vents open and extraction fans cycling off and on. They like to have a little chat in my 40 C environment.
Myself, Slioch and others count as the middlemen/ women who understand enough to translate the scientists speak into analogies and explain things again and again. All over the world there are unrecognised people arguing for the science, and against the idiots.
ReplyDeleteI agree Guthrie, and the Internets is a small subset of the human population. Much, much more work needs to be done. Not in convincing the peoples 'bout warmin', but in what to do about it. There's enough that are convinced about warming that we're moving on, but the delays in doing something are going to be just as long as recognition that there's a problem.
Best,
D
Eli,
ReplyDeletewow, thanks for excerpting all that. I honestly did not have a "trap" planned all along there, I was just really trying to give Kramm a little benefit of the doubt, that it was some sort of straightforward misunderstanding, and if we got the statements of what he's trying to say in a precise enough form, then we could work from there. No such luck though. I do still find it hard to believe this stuff is deliberate - particularly when they're flinging around words like "scientific fraud"! That's pretty audacious for somebody who's consciously trying to confuse or obfuscate people, not to mention occasionally stating things that are simply untrue (at least if interpreted as they seem to be implied).
By the way, I've exchanged some email with Dr. Gerlich. For some reason, every one of his responses was in German - luckily I was able to get some translations. I'm not at liberty to share the stuff he sent me (none of which was a direct response to anything I asked), but they've apparently been doing a lot of throwing their stuff around - letters to Angela Merkel, presentations at various conferences etc. How do they honestly get away with all this? Ah well...
Arthur,
ReplyDeleteI didn't think you did, but it functioned as a trap because after you told Dr. Kramm where his argument was going, he charged right ahead into the punji sticks.
Yup, Kramm charged right in. Is that a sign of simple foolishness, or deliberate self-sacrifice for the sake of promoting confusion?
ReplyDeleteBy the way, Andy Revkin has (finally) closed comments on that whole thread at DotEarth - not too surprisingly "kim" got the last word, with comment #1200.
My formal response to G&T here:
ReplyDeletehttp://arxiv.org/abs/0802.4324
"Proof of the Atmospheric Greenhouse Effect".
Contrary to the claims of G&T, I show here that:
1. An average surface temperature for a planet is perfectly well defined with or without rotation, and with or without infrared absorbing gases.
2. This average temperature is mathematically constrained to be less than the fourth root of the average fourth power of the temperature, and can in some circumstances (a planet with no or very slow rotation, and low surface thermal inertia) be much less.
3. For a planet with no infrared absorbing or reflecting layer above the surface (and no significant flux of internal energy), the fourth power of the surface temperature always eventually averages to a value determined by the incoming stellar energy flux and relevant reflectivity and emissivity parameters.
4. The only way the fourth power of the surface temperature can exceed this limit is to be covered by an atmosphere that is at least partially opaque to infrared radiation. This is the atmospheric greenhouse effect.
5. The measured average temperature of Earth’s surface is 33 degrees C higher than the limit determined by items (2) and (3). Therefore, Earth is proved to have a greenhouse effect of at least 33K.
-----
Silly to think this was even needed, but, I hope it helps. Spread it far and wide if you feel like it! :-)
Arthur, many thanks. We gave your comment it's own post (who would be nutty enough to scroll down to the bottom of this monster?)
ReplyDeleteEli
I see this is well after it was originally posted, however:
ReplyDeleteAs a mere physics graduate, it does seem to me that EliRabett et al come off the worse for ware in this argument.
To take a specific example, and I would say embarassingly egregious (even at my mere graduate level), the reply to Kramms quotation of Pauli:
“there does not exist a device which, working in a cycle, permits heat to be transferred from a reservoir at one temperature to one at a higher temperature without compensating changes”.
with
"Eli points out that Kramm's quote from Pauli was incomplete in important ways
...
(Kramm) somehow omits the clause immediately following in parentheses:
–(that is, unless at the same time mechanical work is done, or energy is supplied from the surroundings by some other means)–
such as sunshine, which falsifies what Kramm has claimed."
It clearly does not falsify it in the slightest.
An input of heat energy to the hotter reservoir (ie the sun striking planet earth) WILL not miraculously cause heat to start flowing from the colder to warmer reservoir. Pauli's bracketed comment was that there are situations where work done/and or energy can cause heat to flow in the other direction. It was not that ANY application of work or energy immediately invalidates the general stated principle.
Getting such fundamentally basic things wrong, makes the Rabett et al position look particularly bad from the point of view of people like me who know a little about the subject. It's like you guys deliberately want to mislead (whether or not the xarxiv manuscript is correct or not, I have no inclination to spend the time necessary to try and figure it out myself)
Yeah well Joe, Eli has two degrees in Physics, so let's cut to the chase. The claim in G&T is that heat CANNOT flow from the colder atmosphere to the warmer surface IN ANY AMOUNT WHATSOEVER. This is a crock. The second law, even without work input simply restricts the NET.
ReplyDeleteSomehow they neglect to mention that the NET heat flow is from the surface to the atmosphere and not visa versa. The NET is what is reduced by the IR back radiation
You don't need to talk about the solar input to falsify G&T's argument.
Eli, thanks for the reply.
ReplyDeleteI have now spent an evening reading briskly through the GandT paper.
As far as I can tell, they do make the argument that there can be no NET heat transfer from upper atmosphere to lower atmosphere/earth.
Furthermore, and again as far as I can understand, the section we are basically discussing is 3.9.3 where they are claiming that the standard "greenhouse gas model" seems to imply NET heat gain of a warmer reservoir at the expense of a colder reservoir.
To me it seems they have a point, although I may be misunderstanding the "greenhouse gas model". Here are the steps in my conclusion:
1) The standard "greenhouse gas model" states that due to an increase in CO2, more of the radiative outflux from the surface of the earth is reabsorbed in the troposphere (im using that as a general term for the main layer of the atmosphere as far as effect is concerned, although it may not be terminologically correct...) and prevented from being emitted out into space, resulting in an increase in temperature of the troposphere.
2) TandG say the troposphere is significantly colder than the earths surface, so by the second law of thermodynamics there can not be a net transfer of heat to the earths surface from the troposphere.
That seems pretty clear to me, and hard to argue with. What am I missing ?
Hi Joe,
ReplyDeleteSimply that any energy returned to the surface by back radiation will warm the surface.
Let us use simple numbers. Suppose 200 W/m2 from the sun is absorbed by the surface and 400 W/m^2 leaves the surface by radiation and convection (These numbers are rounded but not too far from the actual ones).
Now if all of the radiation never returns to the surface there will be a net outflow of 200 W/m2 and the surface will cool until the amount leaving the surface is a lot lower than it is.
Suppose 100 W/m2 of the 400 W/m2 from the surface radiates to space and 300 is absorbed in the atmosphere. Of the 300 assume 100 radiates to space. The other 200 W/m2 is reradiated from the atmosphere and absorbed by the surface. The amount of heat leaving the surface is 400 W/m2, tha amount returning is 200 W/m2 which when added to the solar contribution of 200 W/m2 balances. Thus the temperature of the surface stays constant.
G&T says NO radiation can travel from the atmosphere to the surface because the surface is warmer. G&T are spouting nonsense.
Thanks for the reply again.
ReplyDeleteI can see a major problem with your numbers (or at least I think I do).
Assuming your figures are correct, approx 400W/m^2 leaves the surface by radiation and convection.
It is convection which is the big effect here - radiative loss is I would expect a very small percentage of that. (Actually GandT mention an interesting experiment which seems to show precisely that - basically two "greenhouses", one with glass which would prevent the loss through re-radiating and one with clear salt crystal which would not prevent re-radiating. The temperatures in the greenhouses were more or less identical).
Heat transfer back to earth would therefor appear to be minimal for the following reasons:
a) It cant be done through convection, which is by far the major heat transport mechanism
b) Since the "radiated" part of the temperature is approximated by T^4, and assuming earth = 20 deg C, troposphere = -40 deg C, any tropospheric radiation must be HALF that of the surface, more than half of which would radiate into space anyway. So the flow of radiated heat back to earth would be one quarter of what was already a very small percentage of the total heat lost by the earth through convection and radiation.
Again to respond to your claim concerning TandG saying "NO radiation can travel from the atmosphere to the surface because the surface is warmer". I could only find in their article that they said there could be no NET transfer.
"It is convection which is the big effect here - radiative loss is I would expect a very small percentage of that. (Actually GandT mention an interesting experiment which seems to show precisely that - basically two "greenhouses", one with glass which would prevent the loss through re-radiating and one with clear salt crystal which would not prevent re-radiating. The temperatures in the greenhouses were more or less identical)."
ReplyDeletePlease, not again! Greenhouse effect is a metaphor. The atmosphere does *not* work in the same way as a greenhouse, therefore that example doesn't disprove anything. It is in fact the radiation that is involved here and that is also what all the text books say. Where's the problem, really?
It's great to follow the great debate, but somehow the essence of G&T's paper is being missed - whether or not the logic and physics is correct, is there any data which shows CO2 contributes to the GH effect?
ReplyDeleteIf not, then we (the inhabitants of Earth) are chasing the wrong culprit for global warming (I am clear that ocean acidification is likely to cause us grief also - but that is another question).
Unfortunately for us, as G&T point out, we really don't have very good science for global warming.
We have many people building careers in the field. A little like the frenzy with alchemy "lead into gold" and other such fads. It got humanity nowhere - perhaps even went backwards for the advancement of a few.
Shame - it brings the Physics into disrepute.
And should we not forget, we are facing some real changes on this planet.
Kostas Mitropoulos or "continuous".
Kostas, everyone who understands how molecules absorb and emit radiation knowns that increasing greenhouse gas concentrations results in a warmer surface. You could, for example, look here. The basic idea is that the presence of greenhouse gases slows up the rate at which energy, in the form of infrared light, is emitted from the earth, by engaging in a dance of absorption and emission events. To compensate this, the surface has to warm in order to emit even more IR energy.
ReplyDeleteHowever, G&T are simply clueless.
What a splendid dialogue of the deaf, Eli. The heart of the matter is that energy is characterised both by quantity (first law, conservation) and quality (second law, entropy). If heat flows spontaneously from a cold region to a warm region, the change in entropy, delta Q/T, will be negative, which is absolutely forbidden by any mechanism.
ReplyDeleteWoods experiment was designed to verify this, which is why G and T go on about it at such length. The glass in his test represents an absorptive atmosphere, and the rock salt a non-absorptive atmosphere. The interior represents the surface.
If the conventional calculation of the radiative effect in the glass greenhouses were correct, the incoming radiation would be W, the outgoing radiation from the interior would be 2W, the back radiation from the glass would be W, and the outgoing radiation from the glass, W, would be equal to the incoming radiation. In the rock salt green house, the incoming and outgoing radiations would all be W, because there would be no absorption.
The effect of insulation and convection suppression would be the same for both.
The increase in the interior radiation resulting from the infra-red absorption in the glass is exactly analogous to the “missing energy” which is the heart of the Arthur Smiths’ argument.
From Stefan-Bolzmann, the ratio of the interior temperatures would be the fourth root of 2, or 1.19. If the temperature in the rock salt greenhouse (from insulation and the suppression of convection) is 300 degrees K, the glass interior should be 57 degrees higher. The temperature difference would be 22 degrees K if the absorption was only 50% of the outgoing infra-red.
Within the accuracy of Woods’ rather crude measurements, the temperatures in both greenhouses were the same.
Quite reasonably, Woods concluded that the infra-red absorption in the glass did not heat the interior directly, nor did it increase the effective radiation temperature of the interior, nor did it reduce the outgoing radiation below the incoming, causing the interior surface to heat.
For our 33 degree comfort zone Woods thought we should look elsewhere – not very far, as it happens. The atmospheric lapse rate (a function of gravity and specific heats, nothing to do with radiation) is about 6.5 degrees K per kilometer of altitude. The effective outgoing radiation temperature to space is 255 degrees K, at an effective height of about 6 kilometers.
It would be a pity for this thread to run out of steam, Eli. There are not many that attempt to address the AGW issue from the first principles of Physics.
ReplyDeleteTo take the argument further, we can ignore doubts about “back radiation” and the second law of thermodynamics and apply energy conservation principles to a one dimensional single slab model of the atmosphere.
Page 110 of Elementary Climate Physics by F M Taylor is a good example. The surface receives back radiation equal to the incoming radiation from the sun, so the bare rock temperature is raised by the atmosphere by the factor “fourth root of 2” or 1.19, just as in the case of the domestic greenhouse.
The increase over the “bare rock” temperature is 48 degrees K.
The model is clearly nonsense, because it ignores all other heat transfer effects (evaporation, convection and conduction) and the atmosphere is not a single slab, but it destroys the AGW theory because additional carbon dioxide cannot increase the atmospheric absorption, which is assumed to be 100%.
Your last comment, Eli, is closer to the model proposed by the current luminaries (Houghton, Real.Climate.org, etc) which is set out by Taylor on page 110. The theory, “higher is colder”, starts with the ideal gas lapse rate (temperature change across the atmosphere) which has nothing to do with radiation. It depends on the adiabatic expansion of a parcel of gas with height.
Most of the troposphere is assumed to be opaque to infra-red radiation (all the heat which can be absorbed has been absorbed) so the atmosphere radiates to space from just below the tropopause where the (measured) temperature is about 255 degrees K. It is the lapse rate, not the back radiation greenhouse effect, which gives us our surface comfort zone.
If we (the human race) add CO2 to this model we increase absorption in the upper atmosphere, and move the effective radiation point to a higher level (by about 3 Kms, according to Taylor). At the higher altitude the temperature is colder, the radiation to space is less, and the sun has to warm the whole system to compensate. (Notice that this model does not mention back-radiation, and does not get into trouble with the second law).
The AGW effect depends entirely on the lapse rate, which is perturbed (shifted to the right) by additional CO2.
While this is not exactly “six impossible things to believe before breakfast”, no-one would believe that this is anything other than a marginal effect without evidence.
For the lapse rate effect to be valid, any change in temperature at the surface must be repeated across the atmosphere. There are two independent measurements of these temperatures, the satellites and the radi-sondes. Neither of them confirm the theory.
Tscheuschner nor thee Fred have a clue about thermodynamics. If you had followed the recommended links you would have found this discussion on why a pot of water on a hot plate does not glow red, while without the water it does. Gerlach shows himself to be an idiot there too.
ReplyDeleteThe point is that the NET flow of energy is from the warmer surface to the colder atmosphere, but the back radiation makes the NET smaller than it would be if there were no greenhouse gases in the atmosphere.
As to the rest of your flummery, why should I waste time going through the same hoops.
Sadly, Eli, what is being asserted here is not that the net radiation from the surface is smaller than it would otherwise have been, but that the surface is warmer as a result.
ReplyDeleteThe idea that the back radiation can warm the surface directly is clearly absurd. Can it do it indirectly via the sun?
Apply the argument to Woods’ greenhouses. The back radiation from the glass MUST reduce the NET radiation from the interior, creating an energy imbalance. Since the glass greenhouse MUST radiate more energy to balance the incoming solar heat plus the back radiation, the glass greenhouse interior MUST be warmer than the rock salt greenhouse.
But it is not. Ah well, if the facts don’t agree with the theories, so much the worse for the facts.
As for the pot on the stove, your link misses Gerlich’s point. He is proceeding by analogy (always dangerous). Air acts as an insulator, so the heated pot warms up. Water massively improves the heat transfer , the overall thermal conductivity increases, so the pot cools down. Back radiation from the water has nothing to do with it.
By common consent, it is the atmosphere which is mainly responsible for the balancing radiation to space, not the surface. It is the lapse rate (nothing to do with radiation) which is responsible for the temperature differential between the surface and the effective radiation height, and it is conduction, convection, and evaporation (not radiation) which are mainly responsible for the transfer of heat from the surface to the atmosphere.
Thermodynamics is a subtle subject. It is heat, not energy, which has the ability to do work and warm things up. Heat is the transfer of energy from a higher to a lower temperature. That is why the “higher is colder” lapse rate perturbation theory is the only plausible explanation for any greenhouse effect. It MUST (surely) have some effect on surface temperatures. How much is quite another matter.
“The point is that the NET flow of energy is from the warmer surface to the colder atmosphere, but the back radiation makes the NET smaller than it would be if there were no greenhouse gases in the atmosphere”.
ReplyDelete“Why should I waste time going through the same hoops”, you ask.
Because it might make you think about what you are saying, Eli.
Take the comment above and start with a single slab atmosphere, without greenhouse gasses, covering the planet. Assume that the radiation balance is Win/Wout at a temperature T, where W is proportional to T to the fourth power.
Now add the greenhouse gasses so that the atmosphere becomes a perfect absorber/emitter. Half of the outgoing radiation goes back to the surface, the net outgoing radiation to space falls, and the sun heats the surface until the outgoing radiation doubles to 2W. The radiation ratio (after to before) is 2, and the corresponding temperature ratio is the fourth root of 2, or 19%, just as in the case of the Woods greenhouse.
Crystal clear, incontrovertible, in all the text books.
Now add some additional greenhouse material (CO2 for example). Does more than half of the outgoing radiation go back to the surface. If not, it makes no difference to the fourth root of 2, and the temperature will not increase, which is what Angstrom found when he tried it.
Is there an upper limit to the theoretical greenhouse effect with an opaque atmosphere? Not at all. Just divide the atmosphere into 2 layers, and repeat the energy balance. The outgoing radiation increases to 3F, and the temperature ratio to the fourth root of 3, an increase of 31%, or about 100 degrees C.
With a good diagram and a pencil we can have as many absorbing layers as we wish.
There must be something wrong here, as G and T said.
Freddy, you are setting up a Greek strawman, an atmospheric version of Zeno's paradox. It is just as inapplicable.
ReplyDeleteTo understand what is happening, one has to know a bit of spectroscopy and meteorology. The meteorology is simple, it gets colder with altitude.
If we have an absorber between the ground and space, radiation from the ground will be absorbed in the atmosphere. By Kirchoff's law, all absorbers are emitters, but the emission is characteristic of the temperature where the emitter is. As you add more absorber, the altitude at which there is not enough absorption between the emitter and space to absorb all the emission increases. That means that the altitude at which the emission to space occurs is higher, and the temperature of the emitters at that altitude are colder.
Since the Stefan-Boltzmann law tells us that the emission intensity depends on the fourth power of the temperature, there will be less emission given more absorber. To compensate for this the entire system has to warm.
There are a lot of other details, but not enough space. Go read David Archer's book, Understanding the Forecast for more detail on a simple level.
Thanks for the comment, Eli. Zeno’s paradoxes depend on dividing space or time into successively smaller intervals, which must be summed to infinity to reach a destination. My reductio ad adsurdum depends on the division of the atmosphere into equal slabs, and showing, like Petty, that the surface temperature depends on the number of slabs.
ReplyDeleteWhat you have summarised is the “higher is colder” theory which is the only plausible AGW explanation, and which forms the third part of your response to Gand T. Sadly, it is the one theory which G and T did not address, and it is the least discussed in the blogosphere which remains wedded to thermal blankets or back-radiative heating from colder regions (your parts one and two).
Why does “it get colder with altitude”?. Because the atmosphere is compressed by gravity, is a poor conductor, and so heats up. The temperature lapse rate (looking in the opposite direction) is a function of specific heat and gravity – nothing to do with radiative absorption – and is worth about 33 degrees C top to bottom. The top of the atmosphere must be the same as the bare rock temperature, 255 degrees K, and so we have what we observe.
How is heat transported from the surface to the upper atmosphere? Conduction, convection and the latent heat of evaporation. Without the last two the very low thermal conductivity and the constant solar heat supply would cause the surface to heat to Venusian levels. How do I know this? Because when you interrupt convection in a terrestrial greenhouse (or G and T’s car) you can see the temperature rise very rapidly.
Does radiation have any significant role in heat transfer to the top of the atmosphere?. The Trenberth energy balance (“We are not close to balancing the energy budget – E-mail, 14th October 2009), shows 350 Watts per meter absorbed by the atmosphere from the surface of which 324 comes back. The ratio Out/In is 1.08.These numbers require multiple atmospheric layers because, with 100% absorption and one layer the ratio would be 2. With 3 layers 1.5. With 4 layers, 1.25 and so on. Trenberth’s numbers need 14 layers with a surface temperature of 501 degrees C. I have no doubt that, with a suitable value of atmospheric absorption, the correct temperatures could be forced and the number of layers reduced, but really, what is the point? If radiation is not the principal heat transfer mechanism from the surface to the atmosphere, changing the atmospheric absorption will not affect surface temperatures, which is exactly what Woods found with his greenhouses.
We are left with the impact of CO2 at 380 ppm in the thin air (long photon mean free paths) at the top of the atmosphere. If we believe that CO2 is the only source of radiation to space, then a substantial change in concentration might move the emission level upwards and perturb the lapse rate. This would mean that N2/O2 at a temperature of 255 degrees K, in proximity to space, did not radiate at all, and, as the luminaries at RC were at pains to point out, everything with a temperature radiates.
So, I would not expect surface temperatures to increase with CO2 concentration and as the reliable satellite and radio-sonde atmospheric records shows, it does not. Sadly, no-one actually measures the surface temperatures.
Is my previous post clear, Eli?. The usual paradox is to try to cross a given distance in half steps. The first step is a half, half the balance is a quarter, half the next one eighth, and so on. You won’t get across unless you take an infinite number of steps, because the sum to infinity of such a series is ½ divided by (1-1/2), which equals 1.
ReplyDeleteThe number of slabs into which you and I have divided the atmosphere is finite, and the slabs are of equal width. Any similarity to the paradox arises from the assumption of radiative absorption and emission in each slab – the half up/half down theory following 100% absorption from below. You used this (under the influence of BPL?) in the second part of your paper responding to G and T.
Ignoring the direct transmittance to space, and calling the absorbed solar radiation W, a one slab model gives 2W upwards, W back down, and W to space. Relative to the bare rock case, (255 degrees K) the outgoing radiation has doubled, so the temperature must increase according to Stefan-Bolzmann.
Without testing my ability to type algebra to destruction, the ratio of the temperatures with and without an atmosphere would be the fourth root of 2, or 1.19. The surface temperature would be 303K. Your paper assumed two atmospheric slabs, with two half up/half downs. To deliver W from the top slab to space the surface needs to radiate 3W. The first slab receives 3W from below and W from above, and sends back 2W to the surface and 2W to the top slab.
He second slab receives 2W from below, emits W to space, and sends W back to the first slab.
The calculated surface temperature goes up to the fourth root of 3 times 255, which gives your answer of 335K. Three slabs gives 360K, and so on. Mutiple slabs gives a temperature distribution which resembles the lapserate.
Like Zeno’s paradox it is, of course, all nonsense, but for Physics, not for arithmetic reasons. It is blindingly obvious that radiative energy balance is not the source of the lapse rate, and the primary energy transfer mechanisms from the surface are conduction, convection and evaporation, none of which depend on radiative absorption.
The situation is different in the thin, dry, upper atmosphere, which is why the “higher is colder” theory is (just) plausible.
Fred, you are asking the wrong question about the lapse rate. The lapse rate is set by the temperature of the surface and the top of the atmosphere. Why is the temperature of the surface ~290 K?
ReplyDeleteThe answer is the greenhouse effect and the re-radiation from the greenhouse gases. Without that the surface is 255 K
No, Eli. The air at the surface is relatively compressed. The air at the tropopause is relatively expanded. From the ideal gas laws, compression increases and expansion reduces temperature.
ReplyDeleteTamino has a good explanation at “Open Mind”. He calculates the observed surface/tropopause differential without reference to radiation.
Can I break with the Climate Science conventions and call for an experiment. Do you remember those compressed gas cylinders used to inject CO2 into water bottles to make soda syphons? The cylinder temperature fell so rapidly that water vapour condensed on the surface.
The RC luminaries accept this. Their AGW explanation takes the lapse rate as given, and assumes that increasing CO2 in the upper atmosphere will increase absorption, raise the emission height to a colder level, and reduce outgoing radiation. From Tamino “But the temperature at the surface will be higher than the temperature of this high-altitude air, by an amount which is governed by the lapse rate (which doesn’t change much) and by the height of that radiating layer”
That explanation is plausible. The almost universal multi-layer absorption/emission explanation of AGW is not. The altitude of a layer must (returning to Climate Science) be a function of wavelength and density, but even in the simplest model it must be more than 1, Why? Because the down-welling radiation is similar to the surface radiation, according to Trenberth. The ratio is close to 1 . (If it were exactly 1, there would be zero radiative heat transfer).
With One layer the ratio is 2. With two layers 3/2. With three layers 4/3. To get the Trenberth ratio you need 14 layers (15/14) and consequently an unrealistically high surface temperature.
> Fred Staples said...
ReplyDelete> No, Eli. The air at the
> surface is relatively
> compressed.... compression
> increases and expansion
> reduces temperature.
Oh, dear, the 'compressed air' confusion has been sitting here for months. It appears so many places.
It certainly does, Hank. Whenever you pump up a tyre, or use a carbonisation capsule.
ReplyDeleteIf you want to see it for youself, try here:
http://subaru2.univ-lemans.fr/enseignements/physique/02/thermo/clement.html
Bearing in mind our exchanges on back-radiation from multi-layer atmospheres, Eli, you might be interested in this quotation from one of your co-authors, Chris Colose at RC:
ReplyDelete"This is one of the problems I have with the simple layer model as it is introduced in some textbooks, such as Dennis Hartmann’s or David Archer’s “Understanding the Forecast.” This is where you simply add up the influence from successive blackbody “layers” with a final result of something that usually ends up looking like T_s=T_eff*(N+1)^0.25, where N is the number of layers, and T_s and T_eff are the surface and effective temperatures, respectively. Archer discusses some of the incompleteness of this model in his class lectures (lack of convection, layers are not fully transparent in the shortwave nor fully opaque in the longwave) but I think the whole presentation misses the point completely. It has absolutely no top-of-atmosphere perspective. In fact, if one were to set up the “layer model” with a bunch of layers at the same temperature (i.e., an isothermal atmosphere), the result would be a surface temperature that could be much greater than the temperature achieved by radiation balance with the sun, when in reality, you cannot get a greenhouse effect in such a situation".
Its really very usful and nice post.
ReplyDeleteagenzie di modelle
Oy, a miscomprehension from Fred Staples, a spambot and then a long silence.
ReplyDeleteFred, yes, _when_ you pump up a tire it gets warm as you compress the air.
Yes, the air at the bottom of our atmosphere is more compressed than that higher up.
No, nothing is currently compressing the air any more than anything is uncompressing the air.
Yes, the high and low pressure areas you see on the weather map exist.
No, the average air pressure hasn't been steadily increasing. That's _not_ what's warming the planet.
The planet's "one bar" air pressure at sea level hasn't changed since how long ago?
Long enough there's no extra heat remaining at ground level from that.
Go back and check that spare tire you poked up and found so warm back in 2010. See? It's as cold as the garage it's in, now.