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Frank Davis

Banging on about the Smoking Ban

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Maxwell vs Planck
A brief glance at AGW science.

I've touched on atmospheric backradiation before, back when I was trying (unsuccessfully) to construct my own simple computer simulation model of global warming.

backradiationIn rough outline, Anthropogenic Global Warming (AGW) is supposed to work by short wave solar radiation passing through the Earth's atmosphere and being absorbed at the surface of the Earth, and warming this surface, and being re-radiated back out into space as long wave radiation, some of which is captured by carbon dioxide in the atmosphere, which is warmed, and in turn re-radiates this heat as "backradiation" to the Earth's surface, warming it a little more. This extra warming is AGW. And the more carbon dioxide in the atmosphere, the greater is this warming.

But some physicists object that this "backradiation" is unphysical, in that it requires heat to be transferred from the cold atmosphere to the warm surface of the Earth, and the Second Law of Thermodynamics disallows heat from flowing from cold to warm. From The Science of Doom:

What’s amazing about back-radiation is how many different ways people arrive at the conclusion it doesn’t exist or doesn’t have any effect on the temperature at the earth’s surface.

planck radiation formulaIt seems that this "backradiation" is a feature of quantum physics, whereby energy is supposed to be released in discrete packets called "quanta". The quantum physical view is said to have been developed by Max Planck in about 1900 in an "act of despair" in order to get round the "ultraviolet catastrophe" whereby the classical wave mechanical understanding of radiation embodied in the Rayleigh-Jeans law predicted an infinite (and therefore impossible) energy content of high frequency radiation. Planck's new quantum mechanical understanding did not produce this "ultraviolet catastrophe", and produced a theoretical result much more closely in line with the observed radiation spectrum (see right).

The result has been a somewhat schizophrenic "wave-particle dualism" in physics ever since, with radiation being regarded as made up of waves for some purposes, and as particles or quanta for other purposes.

But according to Claes Johnson, a Swedish professor of mathematics, the classical wave mechanical view of radiation, which Planck had abandoned in order to circumvent the "ultraviolet catastrophe", can actually be used to get round the problem, by using finite precision mathematics.

A black body is regarded a vibrating string, with a number of harmonics, but with a cut-off minimum wavelength, representing the smallest wavelength the string can carry. Incoming waves excite the string harmonics, and these harmonics are re-radiated. High-frequency waves, with a shorter wavelength than the cut-off, are absorbed as incoherent high frequency vibrations which take the form of heat.

The net result is that a warm blackbody can heat a colder blackbody, through incoming frequencies above cut-off. But a cold blackbody cannot heat a warmer, because incoming frequencies below cut-off will be re-emitted without heating effect.

Since "backradiation" refers to the latter case, the model indicates that "backradiation" is not physical.

And if "backradiation" is unphysical, then it can't be happening. And if that can't be happening, neither can Anthropogenic Global Warming. And then AGW will prove to have been the product of the misdirection of physics by Max Planck in 1900 in his attempt to circumvent the problem of the "ultraviolet catastrophe". It may well turn out that the AGW problem has been a consequence of an unfortunate dualism within physics that has grown up over the past 100 years.

AGW devotees may then be seen as being followers of Max Planck ("Planckists?"), and of the orthodox quantum physics of the past century. AGW sceptics such as Johnson may be seen as followers of the older classical wave mechanical view of radiation ("Maxwellians?"). A dispute within physics has spilled out into a high-stakes political conflict.

If so, it will only be physicists - and not politicians or anybody else - who will ultimately be able to resolve the dispute. Either that, or the actual behaviour of the Earth's climate will prove or disprove one party or the other. Since more or less everyone agrees that the Earth has been warming over the past century or so, during which period carbon dioxide levels in the atmosphere have been rising, the Planckists have a fairly good case that the Earth's climate is following Planckist directions. However the fact that it doesn't seem to have warmed at all over the past 13 years suggests that the climate is perhaps more Maxwellian than Planckist.

By no means all AGW sceptics deny the existence of "backradiation". Most sceptics are as Planckist (and orthodox) as AGW believers. Their scepticism is not about the fundamental physics so much as the scale of its effects and the nature of other feedback mechanisms.

This month, however, in the wake of the publication of Slaying The Sky Dragon, of which he is a co-author, Claes Johnson has been subjected to censorship by Swedish university authorities:

The highly-experienced and respected professor has been banned by his bosses from teaching any “part of course material in the course Numerical Methods II.” The material is also found in his ebook, ‘BodyandSoul.’

Dr. Johnson laments, “the course, has been “stopped” by the President of the Royal Technological Institute KTH, because the book contains a mathematical analysis of some models related to climate simulation.”

Well Done, Frank

I won't claim to understand all of the physics involved, but still a straightforward and well explained presentation.


Thanks. I was stretched almost to the limit trying to explain it simply. Glad somebody thought I'd succeeded.




One of the reasons that many non climate-studies engineers and scientists dismiss the claims of the pro-AGW group, is firstly the focus on 'framing' the narrative, and secondly the laughably simplistic nature of their claims.

As an example of the first, they insist that the energy balance of the earth may only be discussed in terms of radiation models, and radiation models made flesh in the shape of 'global average temperatures' and the like.
Any suggestions that the earth/atmosphere system is tad more complex than that, trigger screams of rage and accusations that one is 'denying radiative physics'.
In your post above, you seem to be accepting that framing.

The second is fairly evident in the plethora of simple linear relationships and equilibrium assumptions scattered all over climate studies, as dynamic and chaotic systems seem to be beyond their capabilities.

Dr. Judith Curries blog had some useful comments on the state of the art in radiation models recently. It wasn't pretty.

I think that a great many sceptics accept the radiation physics as well. What's interesting about Johnson is that he doesn't. There are a number of other physicists who have some similar kinds of fundamental objections to greenhouse gas theory.

I don't think that I'm "accepting the framing" by pointing out these objections. Although I'm sitting on the fence about whether these various objections hold water (largely because much of the discussion is a bit beyond my meagre abilities).

I read Judith Curry's threads with interest. Here's one of them. And this may have been its precursor.


Back Radiation is easily measured

So because one guy has claimed that 100 years of modern physics is wrong, it is?

In any case, we measure this back-radiation. If it is "unphysical" and "can't happen", why when you point a pyrgeometer at the sky do you measure around 300W/m^2? We should measure zero if Claus is right.

And why when we capture the spectrum with, say, an FT-IR device do we measure a spectrum with contributions from wavelengths which correspond to the absorption and emission lines of CO2, water vapor, ozone and methane?

This mechanism is not "AGW". This is part of the inappropriately-named "greenhouse" effect. AGW is about increases in the "greenhouse" effect from more CO2 being amplified by feedback mechanisms like ice-albedo and water vapor feedback.

The "greenhouse" effect is basic physics. AGW is a much more difficult subject.

Science of Doom.

Re: Back Radiation is easily measured

Your webpage (to which I linked) makes exactly this point, of course. I read it with interest. I wonder what Johnson has to say about such measurements?



From Brankach:

You state that black body could be viewed as a "vibrating string, with a number of harmonics, but with a cut-off minimum wavelength..."
However, note that vibrating string indeed supports an infinite number of harmonics (modes/standing waves) but has a cut-off maximum,not minimum wavelength - the maximum wavelength is determined by the length of a string and it is twice the length of a string (i.e. the string length is n*half-wavelength, where n is an integer). Provided the fact that the frequency is inversely proportional to wavelength, one could say the vibrating string has the minimum (cut-off) frequency, i.e. acts as a high-pass filter. (see e.g. http://en.wikipedia.org/wiki/Vibrating_string)

Therefore, although it sounds interesting, I am not so sure about such theory of black bodies because it is in fact opposite of what occurs in nature.

I see your point, but if there wasn't a cut-off minimum wavelength, the ultraviolet catastrophe would probably recur.

Re: Harmonics (Anonymous) Expand
Re: Harmonics (Anonymous) Expand
I have to split this comment into two parts.

For the sake of anyone reading this who knows nothing about ‘black bodies’, may I just briefly and simplistically explain?

Over a hundred years ago, scientists wished to examine ‘radiation’ without external interferences. Someone devised a method.

Imagine an earthenware pot shaped like a vase, but with a very small opening at the top – in effect, just a hole. Now, imagine cutting this pot into two halves and coating the interior surfaces with some matt black substance, like carbon. Now, replace the two halves and seal the joints. You have a container which does not reflect any light which enters it through the hole – any light entering through the hole is absorbed by the carbon coating the interior surfaces. You have thereby removed any ‘confounding factors’ resulting from external influences. That is why your container is called ‘a black body’.

Scientists were interested in what radiation might emerge through the hole in the top of the pot. At first, when the pot was cold, no radiation emerged. They then began to warm the pot up. What emerged from the hole was radiation in the form of heat – no light. They could measure the ‘wavelength’ of this radiation and found it to be of a rather long wavelength with not much energy (not much energy because the pot was not very hot). As they made the pot warmer and warmer, so the NUMBER of different wavelengths of the radiation emerging through the hole increased. Thus, not only were there longish wavelengths but there were also shorter wavelengths being emitted as well. But we are still in the ‘infra red’ – that is, in heat radiation and not yet in light radiation. Only when the pot was heated up to a high degree did visible radiation emerge through the hole (in addition to the heat radiation). Of course, the Energy was also increasing all the time.

The visible radiation was red at first and was now of shortish wavelength. As the pot was heated further, the radiation began to include yellow light (in addition to red light and heat!) and then became white light.

At this point, something very odd occurred. In theory, as they heated the pot further, the radiation should have continued to move into the blue section of the radiation wavelength and then into the violet and ultraviolet, but it did not! No matter how hot the pot became, the wavelength stubbornly refused to go any shorter. It refused to go into the ultra violet, although the Energy in the radiation coming through the hole continued to increase (as it would in view of the fact that the pot was getting hotter and hotter).


The equation which scientists had recognised to be true was that ‘as the Energy Increased, so would the Wavelength of the (additional) Radiation Decrease’. But the experiment showed that this did not happen. The Energy could increase without the wavelength decreasing. The ‘catastrophy’ was not a physical thing – it was the destruction of the Equation which had been believed to be true.

This led Plank to formulate his theory that the electrons in the surface of the interior of the black body could only ‘oscillate’ at a given rate within a range of temperatures. In order to oscillate at a greater rate, they had to ‘take a leap’ into that rate of oscillation. In other words, they did not move smoothly from one rate of oscillation to another – they did it in ‘jumps’. These ‘jumps’ indicated that the energy needed to move an electron from one ‘energy state’ (rate of oscillation) to another was A SPECIFIC AMOUNT. This ‘specific amount’ was calculated by Plank (I do not know how) and became known as ‘Plank’s Constant’.

As a matter of interest, the Sun is considered to be ‘a black body’, which sounds a bit daft, considering that it shines. But it is not as daft as it seems when we consider the first thought that we had – which was the exclusion of external influences. The Sun ABSORBES any radiation which might fall upon it and does not reflect it. Thus, any radiation from the Sun is truly free of external influences. It is thus the equivalent of a black body.

Einstein moved the discussion on when he experimented with ‘the photoelectric’ effect.

Here is a simple description.

Einstein shone a beam of ultra violet light onto the surface of a piece of lead. Electrons were dislodged from the surface of the lead. The electrons jumped off the surface of the lead to a specific height above the surface. He thought that, if he increased the ‘intensity’ or ‘brightness’ of the ultra violet light, then the electrons would jump higher. That did not happen. What happened was that MORE electrons jumped off the surface, and jumped to the same height as before. The conclusion to be drawn from that experiment is that when we say ‘increase the intensity or brightness of the light’, what we actually mean is ‘increase the number of light beams’. We can therefore infer that each light beam has a certain energy – sufficient to force an electron to leave the surface of the lead and ‘jump’ to a definite height above the surface of the lead.

Thus Einstein ‘proved’ Plank’s theory to be correct.

I hope that this contribution is worthwhile and that it is not too simplistic.

Maxwell vs Planck

What a dangerous thing a little knowledge of physics is. Now I see that Greenie Watch has run with your article, and once again left themselves open to criticism. I fully condemn AGW propaganda, but this sort of amateurish speculation is damaging to the cause.

Re: Maxwell vs Planck

My, my...

So they have.

How extraordinary!

The amazing support that Claes Johnson seems to have illuminates an interesting point.

What is skepticism?

To me, skepticism is challenging ideas, especially well-accepted ones, and not taking "the consensus" as necessarily true.

It also means not embracing an idea just because it gives support to your point of view.

Many people take issue with the theory known as "AGW". A much smaller number take issue with the inappropriately-named "greenhouse" effect.

But Claes Johnson is someone who claims that one of the foundations of the last 100 years of physics and thermodynamics is wrong. This is a foundation that has withstood 100 years for very good reasons - it is very strong. Validation of Planck's law is found in so many areas of physics.

If you find yourself accepting Claes' theory, ask yourself if you can articulate the reasons why it is true and modern physics is false.

If you read Claes Johnson's paper he moves from disputing Planck's law to disputing one well-proven aspect of modern climate science with no apparent linkage between the two lines of thought.

I ask the people who accept Claes Johnson's ideas - what has he actually demonstrated is wrong with the "greenhouse" effect? "Demonstrated" doesn't mean "stated".

And if you can't understand his paper, then why accept his conclusions?

His paper is "Computational Blackbody Radiation" dated September 16, 2010

what is the connection between parts 1-7 full of maths and part 8? - where he says:

"A main lesson of this note is that “backradiation” is unphysical because it is unstable and serves no role, and thus should be removed from climate science.."

And what is the relevance of part 7.8?

I could write a paper full of maths and at the end say "A main lesson is that gravitational forces are unphysical and should be removed from physics textbooks"

But have I proved it? Or have I just confused the people with no maths background?

There's no evidence for his claim, no proof, and no actual connection with the first part of his paper.

Re: What skepticism means

I think it's alright to debate about such issues - the "debate is over" type of view is not suitable in science (note that even physicists themselves used to be wrong). As for the claim of "100 years physics and thermodynamics is wrong" - one could say Einstein found that 200 years of Newtonian mechanics is incomplete...

Mr. Johnson has provided an alternative view of black body radiation, however it's a bit more complicated than the vibrating string model described in this post. Here I have found the summary of his views:

He states that "a black-body can be seen as a network of interacting atomic oscillators which are excited by incoming waves and can emit waves by coordinated oscillation
". Of course, it's a theory, although sounds interesting...

I've highlighted Claes Johnson because people like him (and he's by no means the only one) are far more radical than most AGW sceptics, in that they not only don't accept the AGW hypothesis, but they also don't accept some aspect of the physics underlying it. They're not just calling climate science into question, but fundamental physics.

And with that, the civil war now going on within science would seem to have widened and deepened. Unless, of course, they can be dismissed as a "tiny minority" of "cranks", and the appearance of normality restored.

But that's what the AGW guys tried to do with the AGW sceptics, and it backfired badly. Are the physics guys going to be any more successful dealing with these new physics sceptics?

The AGW controversy is, as I've written before, a fire burning in academia. And it's a fire that's threatening - like fires do - to spread and consume more and more. There is the potential for the whole lot to go up in flames - particularly when most universities are chock full of pseudoscience tinder (e.g. sociology).

What is and isn't good science? And how do we tell? And now that orthodox AGW climate science is being dismissed as a 'religion', how do we distinguish science from religion? Today's big headline in Climate Depot reads:

German Climate Professor Slams 'Climate Religion': Refutes claims of 'hottest decade' as 'a joke' -- 'Determining a global avg. is a tricky business and in the end is only a theoretical value'

In what sense is what is going on here very different from the disputes that broke out within Christendom 500 years agao, and led to the Reformation?


It's will always be a "Yes, but.."

This is all very interesting but still seems to become a "so what?". Mostly, what difference does it make if there is quanta in black box or waves since none of these discussions I've read show how one jumps from the infinitesimal black box to the macro solar system. Reminds one of studying electrons and, eventually one presumes, will derive Newton's laws of motion. Just too big a gap to brush in the pieces. Let's model the Earth's temperature using black boxes.
Imagine the Earth and it's atmosphere composed of concentric "shells" made up of black boxes. We'll use cubes to make the math simple but, of course, the number of black boxes needs to be enormous. These shells extend from one cube at the center of the Earth out to the past particle of mass that is part of Earth's atmosphere. Assign one gradient value to each surface of each black box and one internal temperature at the center of each each black box. This gives us a seven-variable black box, for starters (the sides and the center). To make things even simpler, assume the contents of each box is known, that it's uniform and that all it's thermal (wave or quanta) properties are known. Thus, we've constructed a simple system where one can use the boxes' side variables to compute the center's temperature. We can then take a "shell" defined as all the boxes at a specific distance from the center and just sum up each boxes center temperature to get "shell temperature". Sum up adjacent shells of your choice and we have computed the "global" temperature.
The problems are immense. As we progress away from Earth's center, each shell lose uniformity within the shell. At the Earth's surface, there will be water, land, atmosphere, all within the shell. Then you have to add the fact that the composition inside the box varies over time. Then add the fact the shells can increase of decrease in number (gasses expand don't they). Then add all external variables which effect the thermal characteristics of the material inside a box.
The model folks then "simplify". Given a few minutes, one should be able to list a few dozen. But they're based on conjecture. For example, if the atmosphere in continually warming, the black boxes a few feet down should become warmer? Then there's the vegetative layer. Just modelling a single plant in an open field is a challenge climate scientist just ignore.
It's laughable reading the "energy budget" equations and the leap models using that as a starting point. This article does point out that it will be physicists that will prevail regarding the science versus the Druids chanting around their models. Whatever model is derived will not start with the "budget". For example, creation and effect of cloud formation as "hard" science and not "simplified" science.

Maxwell vs Planck

Many thanks for the article, it is of great help to understand where the science is.
Have there been such physical experiments to measure radiative transfer and if a lower temp body can influence higher temp body temperature through radiation?
I mean seeing how a higher temp body A cools through radiation. If in vicinity appears a lower temp body B and there is only radiation transfer does such situation result in higher body A temperature curves?

Re: Maxwell vs Planck

You might be interested in this from Dr Roy Spencer.


Re: Maxwell vs Planck (Anonymous) Expand
Maxwell’s equations indicate that re-radiation must be a fact. Perhaps people’s understanding of the 2nd Law should have the phrase ‘in a closed system’ incorporated.

In the daytime, our atmosphere is not a closed system because of the Sun. In the night time, it is (provided that we ignore volcanoes and such). During the night time, it must surely be true that the Earth radiates away excess heat which it has absorbed and retained due to gases in the atmosphere - if it has time to do so. I wonder if sufficient thought has been given to the time element of over-night radiation into space?

Perhaps someone could enlighten us regarding this matter.

our atmosphere is not a closed system because of the Sun

junican, well I would not see the atmosphere as a closed system in the night neither, I imagine the atmosphere is also losing heat through radiation to the higher strata and further, maybe not so efficient as the earth but still do.
Also the atmosphere is not "a mirror" that's reflecting radiation back to earth. radiation is re-emited in all directions. I would understand that a warmer atom has higher probability to emit radiation that a colder one, which would result in a total heat transfer through radiation from warm to cold.

Hello Lars.

In my last post, I was trying to be as brief as possible. Perhaps I should explain what I meant.

In my 'night time closed system', I included space. In that case, there is no external imput to the system as there is during the day (from the sun). Thus, the whole 'Earth system' must obey the 2nd law, and radiate heat into space.

I was aware of the random direction of CO2 radiation. I vaguely thought of this as being understood and included in whatever mathematical calculations are made.

I read the link provided by Frank in his reply to you above re Dr Roy Spencer. In it, Dr S attempts to 'prove' that heat can flow from a cooler object to a hotter object. It is hard to fault his logic. He imagines a plate (Plate A) which is heated by an electric coil and which is placed in a vacuum chamber whose walls are very cold. Plate A is heated to 150 degrees and that temperature maintained as heat is radiated away and 'captured' by the cold walls. He then introduces Plate B and places it adjacent to Plate A. Plate B will heat up (say to 100 degrees) as a result of radiation from Plate A. Plate B will then re-radiate heat to Plate A and cause the temperature of Plate A to rise above 150 degrees. He says that this shows that heat can flow from a cooler surface to a warmer surface.

The only fault in the logic that I can see is that the system that he imagines is not a closed system. One could just as easily say that it is the electric energy coming in from outside which is causing Plate A to become hotter as much as it is the re-radiation from Plate B. As I tried to figure out the logic, I asked myself, "What would happen of the electricity supply was cut off?" I would imagine that, in that case, back radiation from Plate B would not have the effect on Plate A that he envisages (increasing the temperature of Plate A above 150 degrees). At best, Plate B would slow down the loss of heat from Plate A for a short time. In due course, this now closed system would achieve equilibrium.

Is that right or wrong?

The reason that I mentioned night time was that I have seen nothing which mentions it.

Hi Junican,
Sorry, misunderstood you. I'm the wrong one to give advice as I was looking for advice :) on that one, I was looking for physical experiments to understand the math.
I think you are perfectly right in your explanation and if the power is turned off the 150 degrees plate will get only colder, doesn't matter how many 100 degrees plates are around.


I am not a physicist, but find this analysis dubious. First, there are planets where the atmosphere is high in CO2 and there seems to be tremendous 'global warming.' Second, the argument rests on the claim that the solar heated earth is warmer than the air, but looked at from a quantum perspective that's not the whole story. The quantum of IR emitted from the earth hits a CO2 molecule [every once in a while] and 'warms it up considerably.' That is one really hot CO2 molecule amoung many atmospheric molecules, despite the fact that this doesn't materially increase the overall atmospheric temperature. Then the IR excited CO2 molecule releases this energy in a quantum that 1/2 the time goes in a [more or less] upward direction and the other 1/2 the time in a downward direction. This process probably looks like a giant Pachinko machine with quanta bouncing around, but ultimately some of the re-radiated quanta hit the ground, where it is absorbed and re-radiated as IR. So the mechanism does and can work "even though the air is [generally] cooler" than the earth (during the day).

A couple of years ago I designed an actual experiment to test whether and how much warming would be caused by this back-radiation. I sent of the outline of my experiment to 30 climate scientists/climatology departments. I offered to pay for the experiment and cede all publication rights if they would perform it. I got no takers. I did hear from the Alfred Sloan Professor of Climatology at MIT who said my experiment "was interesting." But he wouldn't communicate after that.

Maxwell vs Planck

I posted earlier “What a dangerous thing a little knowledge of physics is.” Since the 27th April 1970 when the Nimbus 4 satellite sampled the Earth’s EM radiation spectra over Guam, we have had the hard evidence of CO2 IR absorption in Earth’s atmosphere. The captured profile clearly shows the tell-tale fingerprints of CO2, H2O, (H2O)2, O3 and CH4. No need for any further speculation whether CO2 can or does absorb – the irrefutable evidence is there!

CO2 is a linear, symmetrical molecule, and therefore (unlike water vapour) has only a transient dipole moment. This excludes the libration modes from participating in exchanges of IR EM. Of the 3 vibrational modes, the symmetrical stretch creates no dipole moment and therefore does not participate. The asymmetrical stretch has a resonance (2349 wavenumber) which is outside the IR spectrum, and therefore of no concern. The bend resonance at 14.77 microns (677 wavenumber) is the only involved resonance, and is right near the peak of the 300K spectral envelope.

In an abbreviated way, this shows that the hard observational evidence clearly matches conventional physical theories of quantum exchange. There is no Maxwell/Planck battle. These are only models, both of which have predictive power, and to rational physicists, this dualism is without conflict. The 14.77 micron CO2 absorption notch from Mars EM spectrum (where the atmosphere is ~95% CO2) clearly shows that CO2 IR absorption in planetary atmospheres is real. It also clearly shows that Earth has nothing to worry about with any conceivable increase in CO2 atmospheric concentration. In time (and what a pity) the oceans and Henry’s law will mop up lots of atmospheric CO2 as the oceans continue to cool during the almost inevitable coming mini ice-age.

The earlier link to Roy Spencer’s lay explanation of why there is no violation of the second law of thermodynamics is clear, conventional and valid. I’m sure that in due course, some of the blatant crank-physics in “Slaying the Sky Dragon” will be well exposed. It is a great pity that Tim Ball and some of the others will come to be tarnished by the association.