cafeamericainmag.com
There has been a lot of CW discussion on climate change. This is an article written by someone that used to strongly believe in anthropogenic global warming and then looked at all the evidence before arriving at a different conclusion. The articles goes through what they did.
I thought a top-level submission would be more interesting as climate change is such a hot button topic and it would be good to have a top-level spot to discuss it for now. I have informed the author of this submission; they said they will drop by and engage with the comments here!
Jump in the discussion.
No email address required.
Notes -
Reading through the article I quickly found a couple errors in reasoning. Also overall the writing style doesn't give the impression that the author is deeply knowledgeable in the subject (or in heat transfer generally). Mostly this is unconvincing to me.
The author gives insinuates that this somehow violates the laws of thermodynamics, but it doesn't. I can't tell if he doesn't understand this or is being intentional misleading.
Take two black body radiatiors at different temperatures and places them near each other. Would you say that the lower temperature body radiates in every direction /except/ the side facing the hotter? Of course not. While the net heat flow will be from hotter to colder, it is totally reasonable to talk about energy transfer from colder to hotter as a matter of accounting.
For 2263 w/m2 solar irradiance, 0.7 albedo, 0.85 emissivity, Venus "Should" only have a surface temperature of less than 200c, instead of the 400+c we observe. Internal heating of Venus appears to be negligible (10s of mW/m2 at the surface).
Venus can be explained by a thicker atmosphere and thus a larger adiabatic lapse rate effect. Also see: https://www.themotte.org/post/960/the-vacuity-of-climate-science/203479?context=8#context . It's just not a good demonstration of GHE.
As to the thermodynamics, the arguments are plentiful. I'll just point out two physicists believed that it does violate the 2nd Law and published a peer-reviewed paper to that effect (Gerlich & Tscheuschner). Most others, of course, disagree. The point in the article is that rather than debate it, let's demonstrate it experimentally, in the real world - and this has not been done for the GHE.
text at this link fails to explain why supposedly Venus is not
How it would increase temperature without GHE?
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Your linked post mentions nothing about adiabatic lapse rate nor how it can explain Venus' temperature being much higher than would be predicted from blackbody equilibrium. Care to explain in detail what you mean?
The linked post is meant to show that using Venus to corroborate a model is foolish, as that same reasoning was used to predict it had the same temperature as Earth. It provides just as much support to any more modern theory, namely, none at all.
For an adiabatic lapse rate on Venus description see: https://youtube.com/watch?v=_4KG0-2ckac ,
Yeah, and Lord Kelvin estimated age of Sun to be about 32 million years (IIRC). Noone claims that scientists are always right.
Can you provide anything supporting this claim in text version? Crankery existing only in video format tends to be extraordinarily low quality and lame.
You're missing the point, perhaps deliberately?
The question centers around why experimentation is important. Anyone can observe something and then make a model up to explain that observation. This does not, and cannot, demonstrate the model is correct. Scientists were wrong about the surface temperature of Venus before it was measured -- yet they made models that perfectly predicted their (incorrect) surface temperature. That their model matched their prediction did not corroborate the model in any way, as is obvious by the fact that it was wrong.
Since then, scientists have measured the temperature of Venus. And now... they have made models to perfectly predict that (correct) surface temperature. Because this time around the temperature is correct, it feels like the model is thus more correct (on this basis) than the previous one. In a sense it is, in that it gives the right temperature. But it is no more (or less) validated by this than the incorrect model! The evidentiary value is exactly the same. You can always make a model fit certain data points, it doesn't mean the model is correct.
Obviously, since we learned about actual Venus temperature any models are expected to predict correct results there.
Doing anything else would be deeply silly.
Specifics how models are build/used/validated are depending on a model. But not rejecting reality and what we learned is hardly indictment of science.
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I'll second the request for something not a video.
I've collected these links as well, albeit they are more technical than the video. Will I next be asked to provide a simpler one? :)
Looking around a little online, I found some people arguing online that of course temperature and pressure make sense together, by the ideal gas law. But they were saying that this doesn't suffice to say that pressure suffices to explain the temperature, as it could be (for example) that temperature affects pressure, rather than the other way around.
What is your evaluation of that argument?
I would say observe that whenever a gas is compressed, the result is both higher pressure and temperature. Gravity compresses a gas as it pulls it to the ground, so this will of course heat it up as well as increasing the pressure.
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See answers posted to that question?
Also, how it even relates to how supposedly "adiabatic lapse rate" can explain Venus' temperature being much higher than would be predicted from blackbody equilibrium?
adiabatic lapse rate here is effect of GHE on Venus. If GHE does not exist, why Venus is much hotter than blackbody equilibrium would predict?
The adiabatic lapse rate falls naturally out of the force of gravity, and non-radiative properties of gases. For the dry adiabatic lapse rate it's actually just the strength of gravity and the heat capacity of the air. You can find a derivation here: http://www.atmo.arizona.edu/students/courselinks/fall10/atmo551a/AdiabaticLapseRate.pdf .
For the moist rate you have to factor in phase-change considerations of the water. This decreases the rate, i.e. the air cools more slowly when water is involved.
Any GHE would have to be on top of/in addition to this. But if the adiabatic lapse rate alone nearly perfectly explains Venus's temperature distribution...
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I found those readable enough. Thanks!
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After admonishing me for comparing model predicted temperatures of Venus to observation, you link me to a video where the adiabatic lapse model is compared to observations, asserts without independent evidence that this fully explains venus' surface temperatures, and what's more tries to generalize this to earth. This is unsound logic by your own argument.
In any case, I would appreciate it if you would explain your position to me in text, here, rather than sending me links. Or at least provide additional commentary along with the link. After watching that video I am no closer to understanding how adiabadic lapse rate results in surface temperatures in excess of blackbody nor why I should favor this over the greenhouse effect.
Sure. The grand canyon is a good starting point. The temperature at the bottom of the canyon is hotter than at the top. Why is that? It's not due to the greenhouse effect. It's due to earth's adiabatic lapse rate.
Essentially, gravity pulls air in the atmosphere downwards, doing work to compress it, which increases its pressure and temperature. The hotter air then starts expanding and rising (being displaced by the cooler air being brought down), which causes it to cool and decrease in pressure. This is an ongoing process. Notably, it has nothing to do with any radiative properties of the atmosphere (i.e. the greenhouse effect). It can be calculated from basic values of the mass of air and gravity: https://phys.libretexts.org/Bookshelves/Thermodynamics_and_Statistical_Mechanics/Heat_and_Thermodynamics_(Tatum)/08%3A_Heat_Capacity_and_the_Expansion_of_Gases/8.08%3A_Adiabatic_Lapse_Rate .
The lapse rate is essentially the same on Venus as on Earth, and as Venus's atmosphere is thicker than Earth, the lapse rate has a longer way to go, resulting in a higher temperature increase. It must be noted the pressure on Venus's surface is 90x that of Earth's.
The blackbody calculation presumes no atmosphere and thus no adiabatic lapse rate. The presence of an atmosphere and gravity introduces this mechanism by which work is done, heating the air as it compresses and gets close to the surface. It explains the tropospheric temperature gradient and, it must be re-iterated, has nothing to do with any radiative properties of the air. Any atmosphere, even one without any greenhouse gases whatsoever, would have this feature.
The question then is: as the adiabatic lapse rate explains the grand canyon temperature difference, why would it not also explain the temperature difference between the surface and the effective blackbody temperature? It must be noted the effective temperature of Earth (255K, -18C) is indicative of the average amount radiated by an entire column of surface plus atmosphere above. As we've established there must be a gradient due to the lapse rate, the average of this column must necessarily be somewhere in the middle. Below is hotter, above is cooler.
This doesn't make any sense to me. The adiabatic lapse rate describes how the temperature would change if you took a parcel of air, did not allow it to exchange heat (that's the adiabatic part, right?) and moved it up or down so it expands or contracts. As pressure increases or decreases, so does temperature.
But in the Grand Canyon, if gravity is pulling cooler, denser air down, and letting warmer, less dense air rise (as must happen), that's going to result in a cooling effect, not a warming effect. Yes, the cooler air may get a bit more compressed as it falls, and thus rise a little in temperature, but you're also losing warm air that was even warmer when it was at the same altitude, so air circulation would result in a net loss of heat. If you have two regions of air at the same altitude and one is warmer, it will have a rising force compared to the other. Gravity can't make it fall relative to the other one. (To be precise, they could both be rising or falling, just that the cooler one will always fall relative to the warmer one, unless there's momentum of air coming in from outside the system and interacting with the geometry of the landscape, like winds blowing across the canyon).
Gravity is not pulling air downward in a thermodynamics-violating way. If we started out with an atmosphere that was not in steady state, where it was a lot more diffuse and bigger than it should be, then yes, as gravity pulled it down and compressed it, it would get warmer. But that would only happen once (or rather it would oscillate like a spring for a while but eventually settle down).
So yeah, I don't get this at all. I don't know if the temperature gradient at the Grand Canyon is completely due to the greenhouse effect, but I'm pretty sure it's not anything to do with what you're saying, unless I'm misunderstanding you.
Consider the air at the elevation level at the top of the grand canyon. The air that is at ground level at this elevation (eg past the top rim of the canyon) will have a certain temperature. If the grand canyon didn't exist but were equally flat with this ground level, the air there would be the same temperature, right? This is the equilibrium at that height.
Now bring the grand canyon back into existence and allow that air to fall. What happens? As it falls, gravity compresses it, and thus heats it up. By the time it reaches the ground it will be hotter. On its way down, this falling air will displace the air further below it, causing that air below to rise and, due to the lower pressure, expand and cool on its way back up. Thus you have a circulating effect, with the equilibrium temperature increasing with depth.
It doesn't violate thermodynamics as gravity is doing work on the gas, converting potential energy to kinetic energy and increasing its temperature on the way down, while via buoyancy pushing the lower, warmer air up. With no further energy inputs the whole column of air would gradually cool (and eventually freeze and fall out of the sky), but the sun provides the "seed" energy by warming the surface which then warms the air via conduction & convection.
Without the lapse rate basically all ground-level air at any elevation would be the same temperature, the temperature achieved by the sun's warming -- with perhaps mountains slightly warmer as they are closer to the Sun. But the lapse rate additionally causes this effect of warmer air below and cooler air above.
You don't have to take my word for it! Some links:
"You can thank a weather phenomenon called adiabatic heating. As air sinks down into a lower elevation, it gets compressed, compressed air releases heat as energy. This caused the air mass to become even warmer.".
https://edition.cnn.com/2020/06/24/weather/arizona-california-heat-forecast-grand-canyon-shoes-trnd/index.html
"In adiabatic cooling, when a mass of air rises—as it does when it moves upslope against a mountain range—it encounters decreasing atmospheric pressure with increasing elevation. The air mass expands until it reaches pressure equilibrium with the external environment. The expansion results in a cooling of the air mass.
With adiabatic heating, as a mass of air descends in the atmosphere—as it does when it moves downslope from a mountain range—the air encounters increasing atmospheric pressure. Compression of the air mass is accompanied by an increase in temperature."
https://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/adiabatic-heating
"Air molecules play a pivotal role in temperature variation with elevation. When at a low elevation, there are more air molecules compressed together due to the weight of the atmosphere pressing down. As these air molecules are compressed, they generate heat, leading to a temperature increase. Conversely, as elevation rises, air molecules spread apart due to decreased atmospheric pressure, leading to a temperature decrease."
https://science.howstuffworks.com/nature/climate-weather/atmospheric/question186.htm
Here's an interesting question: How would it gradually cool? If the greenhouse effect is not a thing, how can air lose energy to space? Convection and conduction require molecules to impact each other to transfer energy -- but there's nothing in space for the molecules to bounce off of. Are you claiming that first the earth would have to radiate energy to space through a long-wave-transparent atmosphere, then the atmosphere would cool down by losing energy when molecules bounce and impart energy to the cooler earth?
If what you are saying is true, then wouldn't we see that the surface actually cools down faster than the air at night?
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No, sorry, a rhetorical question is not an argument. For the second time, you are still doing the thing you accuse your opponents of: positing that some effect is explained fully by your own pet model without providing any independent evidence that it does so.
Are you or are you not trying to rule out that radiative heat transport is a significant factor in atmospheric temperature?
If you neglect radiative heat transport then atmosphere temperature can only ever be less than surface temperature, which is blackbody.
On the other hand, if you include radiative heat transport, then you must acknowledge that different gasses have different absorption/emission spectra and so their behavior cannot necessarily be compared on 1-1 ( or equal density) basis.
By saying so you are endorsing the point of the article, which is that this isn't sufficient evidence. I agree. I would certainly never advocate spending trillions of dollars on global projects on this basis without doing further research. Yet that's precisely what the climate alarmists want us to do with their "pet model"s.
And trillions is not an exaggeration! "Without creating the conditions for the massive engagement of the private sector, it will be impossible to move from the billions to trillions that are needed to achieve the SDGs.", said by the Secretary General of the UN in 2023: https://www.un.org/sg/en/content/sg/statement/2023-01-18/secretary-generals-remarks-the-world-economic-forum .
Until then, I can just point out that we have two mutually exclusive explanations, that can't both be right, and insufficient experimental evidence to say which is the correct one. Further on the GHE side of it we have a supposedly powerful physical effect with no experimental (and thus causal) proof that it exists (despite all other physical effects being able to be demonstrated experimentally, even gravity with the Cavendish experiment). And on the adiabatic lapse rate side of it we have rock-solid proof that this is how Earth's atmosphere actually does operate (it does have a lapse rate, the dry rate and moist rates essentially perfectly line up with the rates computed from first principles, etc) and thus it must necessarily also operate in Venus's atmosphere (as physics is universal and works the same everywhere).
Hmm... so obviously the only way the Earth as a system loses energy is to space via radiation. The "effective temperature" isn't actually a physically real temperature but rather the temperature corresponding to a hypothetical blackbody that would have the same emission as the average radiative emission of Earth to space. And obviously an entire column of surface plus air above it, is what will as a whole be radiating to space.
The question of whether the radiative heat transport warms the surface past the blackbody temperature is separate from the above considerations.
You're leaving out the entire rest of the atmosphere: conduction, convection, water, moisture, latent heat, phase changes, winds, adiabatic lapse rate, etc. etc.
The moon's effective blackbody temperature is the same as Earth's, -18C. Yet it gets to +120C during the day and -120C at night. It's both much hotter and much colder than Earth and than the effective blackbody temperature.
The entire atmosphere participates in the redistribution of this heat, to be cooler during the day and warmer at night. Not just the tiny percent that absorbs and emits infrared radiation.
By neglecting all that and leaving only one option, radiation, of course your thoughts will naturally be directed towards assuming and thus believing that it must account for everything. But you leave out all the rest.
Not to mention that by considering the effective blackbody temperature, you're considering an average and also neglecting the fact that there's day and night, that the Sun warms the planet more on its day side than night side, etc.
Their non-radiative effects can be. All that is needed for adiabatic lapse rate is to have mass, heat capacity, and gravity. CO2 accomplishes this as well as any other gas.
As to what effect the differing radiative properties have (which differing properties they do have), that is indeed what's under discussion here.
As far as I can see, you still have not given any explanation for how the lapse rate effect can result in temperatures far in excess of blackbody (day/night temps being irrelevant since we are interested in average temperatures)
Take a packet of gas that starts at the surface, rises to its maximum height, and then falls back to the surface. Initially it will be in equilibrium with the surface temperature. If the gas does not absorb or emit significant radiation, then it will have the same temperature at the end of the round trip as the start. There is still no mechanism by which the gas packet temperature would exceed the surface temperature nor by which surface temperature would exceed blackbody.
If a packet of gas does not exchange (absorb or emit) significant energy via radiation then the "whole column of air" will not transfer energy to space.
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