By Andy May

This discussion took place in the comments to Mallen Baker’s post of the discussion between Tom Nelson and Baker on Climate the Movie: The Cold Truth. The full discussion can be viewed here. My review of the movie can be read here, and an annotated bibliography for the movie can be seen here.

The following discussion is between a physicist who refers to himself as “chrisa.4937” or “Chris A.” and me. I found it interesting because we were able to dig a little deeper into the actual physics of the climate system as opposed to way the physics is programmed into the climate models, often called “GCMs” in the discussion. Don’t worry, there are no equations, the discussion is readable. I have edited the full discussion for brevity, spelling, and grammar.

Mallen,

This video shows you do not understand the scientific method. A proposal, such as “humans cause climate change,” is set up to be falsified in science. Then examples are found that falsify the statement, that is the scientific process. Tom provided examples; his movie provided examples. You can’t dismiss them out of hand, the scientific method requires that each bit of contrary evidence be explained or the whole hypothesis is rejected. Providing an alternative hypothesis is not required. You are just one of many alarmists I’ve observed who try to shift the burden of proof to those who are not convinced that “humans cause climate change.” That is unscientific in the extreme.

More specific hypotheses:

a) CO₂ slows down the heat loss of the surface of earth to space.

b) A rise of CO₂ concentration does magnify the effect of a) measurably.

c) The rise of CO₂ concentration is caused by humanity.

Please note that the hypothesis you suggested is not scientific.

 @chrisa.4937  Your points are based on CO₂ laboratory measurements. In the real world, we must rely on climate models to determine if the human enhanced greenhouse effect is a problem or will be a problem. Yet even the IPCC admits the models are wrong:

“Hence, we assess with medium confidence that CMIP5 and CMIP6 models continue to overestimate observed warming in the upper tropical troposphere over the 1979–2014 period by at least 0.1°C per decade, in part because of an overestimate of the tropical SST trend pattern over this period.“ (AR6 WGI, page 444).

The above quote just touches on the problems, even more serious is that the models get all the ocean oscillations (AMO, PDO, NAO, AO, etc., see Eade, 2022) wrong. Not to mention the pattern of ocean warming in the Pacific (IPCC AR6, page 990).

 @andymay52  You seem to think my statement has something to do with models. It is about the most basic physics, far below the level of modelling. We are far far away from discussing models. We are on the level of “Are the laws of thermodynamics valid?“

 @chrisa.4937  On come on! I’m a petrophysicist and I can assure you that there is nothing in basic physics or thermodynamics that says that adding CO₂ to the atmosphere is dangerous. You can’t even show that adding CO₂ will cause warming, although I will admit that in my humble opinion, I think adding CO₂ will probably cause some warming, but it is likely small and benign. The only way you can show it might be a problem in the future is via climate models, and even the IPCC admits they are wrong and predict too much warming based on comparisons to observations (AR6 WGI, page 444).

 @andymay52  I‘m a physicist myself and am baffled by the claims you make here: Of course nothing in physics ever says something is „dangerous“, for this is not a scientific category at all. Science doesn‘t say it is „dangerous“ to pee on a high voltage line. It says „urine is an excellent conductor“.

But the most stunning statement is this: “You can’t even show that adding CO₂ will cause warming[…]“ You cannot even show that, it is an essential consequence of the laws of thermodynamics and quantum mechanics (which explain the radiation activity of CO₂). CO₂ with its radiative properties slows down the export of energy from surface to space while heating by the sun is held constant. In such a setup physics gives no way that adding more CO₂ will not accumulate additional energy in the system.

And NO, this is not shown via models, but on a far more basic level via hypothesis and experiment. The predictions made by basic physics and quantified by Schwarzschild‘s equation were and are tested since the early 1980s and found to be correct ever since. Models are setup ON those findings, not predicting those findings without testing them. The literature documenting this literally takes metres of bookshelves in scientific libraries. The physics of it is in standard textbooks schooling students since decades. And now you come casually claiming this to be not there? Baffling, as I said.

 @chrisa.4937  The point I made was that while CO₂ can be shown to absorb some wavelengths in a laboratory and warm as a result, the Holocene record shows that CO₂ and temperature do not correlate (Liu, et al., 2014) and (Kaufman & Broadman, 2023). The instrumental record shows that temperatures fell from 1944 to 1978 while CO₂ went up (see Figure 7 here).

Second, Schwarzschild‘s equation is a vast oversimplification of the atmosphere; it does not include the effect of changing TPW [water vapor] and clouds. Both change independently of temperature, as I’ve previously shown (see here and here).

As Feynman said, if your beautiful model doesn’t match observations, it is wrong.

 @chrisa.4937  OK, to your points, quoted below:

“a) CO₂ slows down the heat loss of the surface of earth to space.

b) A rise of CO₂ concentration does magnify the effect of a) measurably.

c) The rise of CO₂ concentration is caused by humanity.”

Comments

a) Not true everywhere, in polar winters the atmosphere is warmer than the surface, so additional CO₂ cools the surface. This is important because the polar winters are major heat sinks, especially the North Pole.

b) Measurements do not support this, for example the Holocene Temperature Conundrum (Liu, 2014) and 1944-1978. Kaufman, 2023 tries to explain away the Holocene Temperature Conundrum, but fails and his paper is inconclusive. Data shows that CO₂ is a very minor factor in global warming, other factors “overshadow” it as Kaufman, 2023 admits.

c) This is true.

 @andymay52  You are the first to answer my points. Thx. However, I disagree for more than one reason: You are right that a) is not true everywhere every time. But it is true for the whole globe at all times. Otherwise, the laws of thermodynamics would be broken. You cannot fill a system with energy at speed c, have it export energy at speed c – x (which is true for the surface, where x is the deceleration of radiative energy export due to radiative active gases in the atmosphere) and end up with no higher steady state temperature. This is forbidden by thermodynamics.

To b): Your answer refers to historical measurements scrutinized for correlations. This is in no way a test for the hypothesis. To test the hypothesis, you must measure IR spectra from the ground and from high above simultaneously – which was done for decades and is done still. Millionfold in the meantime. I highly recommend A First Course in Atmospheric Radiation by Grant W. Petty

 @chrisa.4937  WRT (a) well over half of the total radiation Earth receives is in the tropics, yet tropical temperatures hardly change over time. Global warming (or the silly name “climate change” if you prefer) occurs at the poles. The South Pole, like the tropics, is hardly changing, so we are talking about the North Pole at this point in geological history.

Long term Northern Hemisphere weather is a function of meridional transport, the transfer of energy from the tropics to the North Pole, where it is radiated to space due to the small greenhouse effect at the North Pole, especially in winter. The speed of that transport controls the rate of warming or cooling of Earth in this time.

You are trying to treat the Earth as a black body, it isn’t. It is a very active gray body. The atmosphere and the oceans contain more thermal energy than Venus‘ surface, but our surface has a much larger heat capacity. Again, you are oversimplifying the climate system and how it warms and cools.

As for (b), if you are saying that we have no way to tell what the impact of CO₂ is on climate, I agree. There is more evidence that it is small than large, however. The IPCC AR6 conclusion that all the warming since 1750 is due to CO₂ and other GHGs has no support whatever.

 @chrisa.4937  I might add that while it is true that when more energy is leaving Earth’s atmosphere than entering it, the globe cools, and vice versa, to say that is all that matters with respect to “climate change” is wrong. Further we cannot measure incoming versus outgoing radiation accurately enough to know whether net radiation is increasing or decreasing, or (more importantly) where it is increasing or decreasing. Check the problems discussed in Loeb, et al., 2022.

 @andymay52  You are moving the goalposts. My initial three points were pointing to the energy balance sheet of earth. How energy is moved around within the system does not affect the average numbers of in vs. out in W/m².

And as for b): No, I‘m not saying we have no way of telling the impact of CO₂ on climate. In fact, we have a very sound way of telling the impact of CO₂ on global warming, which is highly relevant for overall climate. And this way is given by basic physics, not historical data. This basic physics was researched for more than a century and was and is very well measured and documented in thousands of papers and standard textbooks. Please note that the early predicted consequences of the rise of CO₂ have been measured nearly spot on, e. g. the cooling of the stratosphere, which gave the noble prize to Manabe recently.

You can start by reading his original paper to gain more insight in the physics used for calculating warming ( Manabe & Wetherald 1967 ). This would be a good start for it looks like you have gotten the entire concept of the GHE wrong. To make it clear: GHE has little to do with the radiation budget at the surface but is about the radiation budget up in the atmosphere, where the LWR at the frequencies of CO₂ can leave to space without further absorption. I do not find this concept being reflected in your comments, to be honest.

 @chrisa.4937  I don’t think we are communicating well, this statement from your comment is clearly incorrect:

“How energy is moved around within the system does not affect the average numbers of in vs. out in W/m².”

The GHE is huge in the tropics, it is negative in the polar winter. If you move thermal energy from the tropics to the North Pole quickly the increase in energy out is huge, if not it is small.

The energy-in over the same timeframe stays almost exactly the same. Your assumption that moving energy around the planet has no effect is the largest and most obvious mistake of modern climatology.

I’ve already read Manabe’s 1967 paper. While solar changes are small, the changes in GHE around the Earth are huge and variable and the climate model predictions of them do not match reality. Another problem, cloud cover changes, as a function of hemispheric weather. This also changes the GHE dramatically, and again the models do not match observed cloud cover. Most definitely, how energy is moved in the system DOES affect the average numbers.

 @andymay52  The average number (in power/area) is a requirement given by the 2nd law of thermodynamics.  This law clearly states, that the earth as a whole will always seek the very state in which power(in) = power(out), where power(in) is the income of solar radiation and power(out) is the radiation that earth sends into space. Given that the geometry of Earth does not significantly change, this simply means the power/area output of earth is a value that you cannot change by moving heat around within the atmosphere / on the surface – otherwise you would break the 2nd law.

Your statement reads as if you imply the opposite to be true. In this case there is nothing to discuss, because I won‘t discuss under the premise that the 2nd law doesn‘t hold. What you might have meant instead is the fact that the power of radiative emission of the surface depends on the temperature distribution on this surface. That is correct, but on the other hand known to every climatologist and taken into account by the field.

 @chrisa.4937 The second law of thermodynamics is fine. The problem is your application of it to Earth’s climate system. Because the Earth is not a black body where (energy-in) – (energy-out) is always the same, we must account for energy residence time in the system, a quantity that varies significantly. Related to this, is the constantly changing albedo due to constantly changing cloud cover, but that is a separate issue. Clouds change as the climate system changes, which is why it is related.

Energy residence time is a function of the global circulation system. We don’t understand what drives the global circulation system, but we can observe the changes in the ocean oscillations, the jet streams, the movements of the ITCZ, and in atmospheric circulation patterns (see Wyatt and Curry, 2013, “Role for Eurasian Arctic …” and related papers).

It is important to understand that the critical ocean oscillations (AMO, PDO, NAO, AO, ENSO, etc.) were all discovered after the CO₂ driven GCMs were invented and their basic assumption that CO₂ drives climate change was locked in. Because the critical oscillations cannot be reproduced by the GCMs, they are critically flawed. For a discussion of the problems see Eade, et al., 2022, “Quantifying the rarity of extreme multi-decadal…”).

Sometimes it is more interesting to see the critical issues debated, rather than reading the dry academic material. Climate The Movie sure has sparked some interesting discussions. I leave it to the reader to decide whether Chris or I are correct.