dale-cloudman
30d ago
It appears you started skimming earlier than that, as this is in the 3rd paragraph: "Worst of all, the alleged recent warming trend that is said to confirm earlier model predictions is based on data that appears to be adjusted to match the very models it is meant to be independently corroborating." It is elaborated in the article on the "Correlation is not causation" section.
As to the 2nd Law: "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."
As to thinking the Earth during summer is hotter than the Sun... genuinely not sure what you're addressing here.
dale-cloudman
30d ago
Greenhouses are relevant because the GHE should be the mechanism by which they work. But, they don't. That they work due to the HHE and not the GHE is evidence against the GHE.
dale-cloudman
30d ago
The greenhouse diversion is unfortunate due to the naming but also interesting. We can call it a hothouse instead and call the way it really works the “hothouse effect”, which is suppression of convection. HHE != GHE , of course, so it’s not relevant on that level.
What’s interesting to consider though is that a hothouse made of glass vs a hothouse made of a thin plastic, works essentially as effectively. But the glass absorbs and thus emits more IR, both into and out of the hothouse. This downward IR should, by the GHE, warm the interior much more than the plastic walls which don’t emit nearly as much IR. But, it doesn’t. This is peculiar and points to the GHE being weak rather than powerful as it’s said to be (causing the Earth to be +33°C warmer than it otherwise would be).
dale-cloudman
30d ago
It’s a bit subtle although not really.
The GHE is actually that the surface gets warmer, not the atmosphere. Actually the lower atmosphere (the troposphere) is warmed far more by conduction and convection than radiative effects. The 0.04% quantity of CO2 actually is very relevant here, even if that amount it absorbed doubled, it’s still far outclassed by convection which 100% of the air participated in.
But that’s a furphy as far as GHE is considered, because GHE is really about the extra downward emission of IR, not the atmosphere itself warming due to absorption. This extra downward IR is said to warm the surface more, given same energy input.
This latter piece is what hasn’t been demonstrated and what some physicists argue is thermodynamically impossible. I don’t want to debate the theory of that (most say it’s possible, a vocal few say impossible; not much we can add to it ourselves here), I’d rather defer to experimental evidence, and it being lacking doesn’t look good for the “it’s possible” side.
dale-cloudman
1mo ago
The key here is “experimentally demonstrate”. Pointing to Venus isn’t an experiment! I thought the following demonstrated why rather effectively:
“The problem this poses is best exemplified by going back to Pekeris 1932. (It must be noted that Hansen et al 1983 cites Wang 1976 which cites Goody 1964 who then cites Pekeris 1932). In Pekeris, the models of the time led the scientist to believe that “it becomes plausible the temperatures on […] Venus, Earth, and Mars are about the same”. As Venus’s temperature is 464ºC while that of Mars is -63ºC, his egregious error reveals the fundamental problem of not having experimental means by which to validate models. This leads to a situation where models are susceptible to overfitting available data, with no ability to check their operations by proving that the actual effect matches the model’s prediction.”
dale-cloudman
1mo ago
Hi, the author does address it :)
“Origins of the Theory
If the greenhouse effect has never been demonstrated, then why does anybody believe that CO2 causes warming in the first place? The answer is somewhat embarrassing. The first to propose the effect was Fourier in 1824, who (according to Arrhenius) believed that an actual greenhouse works “because it lets through the light rays of the sun but retains the dark rays [i.e. infrared radiation] from the ground”. Fourier proposed the atmosphere had a similar property. When Tyndall discovered in 1859 that CO2 does indeed absorb infrared radiation, early climate modelers took this fact and ran with it, with Arrhenius doing “the first calculation of the warming of Earth due to CO2 increase” in 1896. But actual greenhouses do not work this way. They work by physically blocking hot air from escaping and mixing with the outside air. This was shown by R W Wood as early as 1909. It is more than strange that despite this falsification, and a lack of any further proof, the theory has persisted to this day.”
The key is that Tyndall showed CO2 absorbs IR, but this in and of itself isn’t the greenhouse effect. The effect is the (extra) warming a surface undergoes as a result of said absorption.
dale-cloudman
27d ago
The day & night is relevant here. The sunlight has the potential to heat the ground to over 100ºC (212ºF). The reason it doesn't get that hot is because the ground conducts heat to the air, which then convects upwards. So the sunlight, during the day, has the power to heat the surface far above the blackbody average.
Then, you just need to compare temperatures at differing elevations to see that the adiabatic lapse rate has a real effect on the temperatures you find there. Compare bottom of grand canyon to top of grand canyon to high up on a mountain-top. The air pressure at all of these levels is, of course, higher than the air pressure would be without an atmosphere, which is zero.
So we know for a fact that gravity causing increased air pressure results in higher temperatures than those found at lower air pressures. This is observable, empirical, and irrefutable. I wrote some more detail about the lapse rate here: https://www.themotte.org/post/960/the-vacuity-of-climate-science/205320?context=8#context .
The atmosphere, thus-warmed during the day, then prevents the night-time temperatures from getting as cold as they do without an atmosphere (-100ºC on the moon), much like how a blanket works.
The net effect of the above is evidently that it is cooler during the day than without an atmosphere, warmer at night than without an atmosphere, and the 'average' temperature is overall higher than without.
dale-cloudman
27d ago
Climate-related deaths have dramatically plunged since the 1900s. It's because of advance in human technology. The way forward is to promote as vibrant and powerful a growth of economy, health, wealth, and technology as is possible, which will allow humans to adapt even better.
dale-cloudman
29d ago
I'd rather have a system set-up where we don't have to trust the people in charge with not ending the world :). They should not have the power to unilaterally do so.
dale-cloudman
30d ago
This was the relevant part: "In closed containers, the differing gas density still affects the rate of convective loss, as #2 points out."
Quoting from the paper, emphasis added:
Even if the experiments were done in a sealed container, and CO2 were compared with Ar, differences in convective transport could not be ruled out.
[...]
In some of the reported demonstrations, the container is sealed so that interfacial mixing should not be a factor, but a temperature difference between air and CO2 was still reported.[3–5] Sealing the container brings into play additional factors, which are difficult to quantify, especially the infrared characteristics of the “window.” In Ref. 5, for example, T is reported to be 25% greater for CO2 than for air. As we have argued, a difference of this magnitude cannot be accounted for by far-infrared absorption. This experiment probably involves the direct absorption of sunlight rather than of reemitted far-infrared radiation, but that effect should be even smaller. [7] Simple models of natural convection suggest that the difference in the heat flow between the two gases should be less than 10%.[17] The calculations depend on the geometry, however, and the conditions are in a transition regime between laminar and turbulent flow, and thus it is possible that small changes could have disproportionate effects. These uncertainties reinforce the value of including a comparison case that uses a heavy gas without infrared absorption, such as argon.
dale-cloudman
30d ago
That would be not due to the GHE (which is radiative) but something else, like say convection loss being less because of warmer atmosphere. If this were the case it would mean all the climate models are wrong, because they all rely on the GHE (downwards IR causing higher surface temps). I'm happy to accept this and then we could talk about what that might look like.
Two points though:
-
In the troposphere the CO2 absorption is already saturated, as Knut Angstrom's assistant found in 1900. So the effect on the lower atmosphere would essentially be nil
-
The alarmists' rebuttal to #1 is that higher up in the atmosphere, at colder and lower-pressure layers, the effect is not yet saturated. Perhaps those, then would become warmer? Yet consider that if the air absorbs more IR, so, too, does it emit more IR. Added CO2 provides the air a way to cool that it wouldn't otherwise have. In fact, the standard understanding of the climate consensus is the stratosphere ought to cool with more CO2 rather than warm up.
So if the troposphere doesn't warm due to more CO2 as its absorption is already saturated, and the stratosphere cools, and the downwards IR doesn't have a warming effect... where does that leave the warming theory then?
dale-cloudman
27d ago
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.
dale-cloudman
29d ago
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...
dale-cloudman
30d ago
It also won't change the point here. I'll try it again with newly coined terms in bold.
The florb effect is a radiative phenomenon. Any object above 0K absorbs & emits infrared radiation. Certain gases, like CO2, also absorb & emit infrared radiation, while others don't. If you increase the concentration of CO2 in the air, the air now will be emitting more infrared radiation, both upwards and downwards back toward the surface. This downward emission of infrared causes the surface to become warmer. This warming is called the florb effect.
A hothouse, by contrast, works by the hothouse effect, a totally different phenomenon. The sun heats the inside of the hothouse, which causes the air inside to become warmer. This air rises, but is physically prevented from escaping by the hothouse walls. This allows the air inside the hothouse to get warmer than the outside air. It is an effect of suppressing convective loss rather than a radiative phenomenon.
The peculiar thing: A hothouse remains equally hot whether its walls are transparent to infrared, or absorbing of infrared! This is despite the IR-absorbing walls emitting infrared into the hothouse, while the IR-transparent walls don't. According to the depicted mechanism of the florb effect, the IR-emitting walls should result in a much hotter hothouse interior. Yet, it doesn't.
Thus, the fact that a hothouse works due to the hothouse effect, and not due to the florb effect, is evidence against the florb effect.
You see now?
dale-cloudman
30d ago
"The greenhouse diversion is unfortunate due to the naming but also interesting. We can call it a hothouse instead and call the way it really works the “hothouse effect”, which is suppression of convection. HHE != GHE , of course, so it’s not relevant on that level."
HHE = the "hothouse effect" I just coined here for clarity in communication.
dale-cloudman
30d ago
The flat earth documentary was fascinating because the guy actually proved the Earth was round in his experiment. Then they had to explain away their results and pretend it didn't happen.
Re: climate science, I think the situation is the same as with medicine. The default assumption on medicine is a new thing doesn't work. So you have to positively prove it. Only then can your intervention be recommended. For climate policy, it should be the same. You want to impose new taxes, de-industrialize (which industrialization has massively benefited humanity), ban synthetic fertilizer (which synthetic fertilizers are responsible for vast amounts of our food production), degrow the economy, etc? Then you have to actually prove, definitively, there is an issue, and that your policy would work.
This is not the state of affairs today. Today it's just presumed that the climate alarmists are right. If you question it they say "the science is settled" and smear you as a "denier" (which grew out of the "Holocaust denier" term). They've flipped the burden of proof in the public and policy sphere. But that's not how science is done. The person proposing the theory is the one that needs to prove it. It's not up to others to falsify it.
That being said I'm working on an experiment that could actually definitively falsify the GHE. Will see how it goes!
dale-cloudman
30d ago
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.
dale-cloudman
27d ago
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.".
-
"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
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"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
dale-cloudman
28d ago
Well it appears my strategy worked. The critique went from "reasonably-easy misunderstanding to make" for someone "without the proper grounding" to: scientists can still be wrong. Mission accomplished.
dale-cloudman
29d ago
The reason to point out that two physicists published a peer-reviewed paper where they argue the GHE violates the 2nd Law of Thermodynamics is to show that it's not a layperson's mis-understanding that underlies this claim. Trained physicists with extensive experience precisely with thermodynamics, made the argument. So it's just not effective to say it's because of lack of "proper grounding".
The terminology can be tricky. For a detailed explanation I refer readers to the paper in question, https://arxiv.org/pdf/0707.1161.pdf, p75-79 in particular.
dale-cloudman
30d ago
Ehm... at the time you wrote this, I provided two links. One was to another post I made in this thread, and one was to a YouTube video. There are no "various YouTube videos" linked, just one (which was related to the discussion), and no "otherwise unrelated content" at all (in fact, no links to other content at all besides the one video). So it seems you're operating on a mind-already-made-up, prejudiced basis and are interpreting what I'm writing via feelings, emotions, and pre-existing beliefs rather than sensible facts and clear-headed evaluation of what I'm writing here.
Your other points are equally invalid. I haven't evaded any questions -- you'll have to point out where I have if you want to make that claim, but you won't be able to, as I haven't.
I haven't written anywhere that I think the GHE is empirically verified. Rather to the contrary, I've written how it hasn't been experimentally verified (https://www.themotte.org/post/960/the-vacuity-of-climate-science/203568?context=8#context). And no, this is not a link to "otherwise unrelated content", it's a link to something else I wrote in this thread.
You are misinterpreting what I wrote about greenhouses. The point is that, the fact that greenhouses don't work according to the GHE (see https://www.themotte.org/post/960/the-vacuity-of-climate-science/203995?context=8#context if you are getting tripped up on the terminology here) does not prove, in and of itself, that the GHE doesn't exist, but it does speak very much against it. This doesn't mean the GHE exists, it just means the fact of how greenhouses work is not sufficient evidence to disprove the GHE.
Perhaps the only valid thing you did write here is that you "don't know a thing about climate models" (your words). I can accept that. But the salient question then is, whence do you draw the confidence with which you've formed your opinion about what I wrote?
To help you answer that question I will re-iterate something I wrote at the start of the article that is very relevant here, with emphasis added: "This is highly relevant because it means our current climate scare is based not on irrefutable scientific evidence but rather on hysteria and alarmist fear-mongering that fifty years of “failed apocalyptic predictions” have failed to abate. This is crucial to understand as it makes it clear that rather than debating how humans should mitigate this alleged impending disaster, the proper focus should be to question why those in power are employing psychological fear tactics to promote taxation, restriction, and degrowth, and why so many intelligent people have uncritically bought into the hysteria when these proposed policies are clearly to their own detriment."
dale-cloudman
30d ago
On experiments:
-
"Benchtop Global-Warming Demonstrations Do Not Exemplify the Atmospheric Greenhouse Effect, but Alternatives Are Available", https://pubs.acs.org/doi/10.1021/acs.jchemed.8b01057
_
(It must be noted the "alternatives" provided are analogues, not demonstrations of the GHE.)
-
"Climate change in a shoebox: Right result, wrong physics", https://www.researchgate.net/publication/243492513_Climate_change_in_a_shoebox_Right_result_wrong_physics .
dale-cloudman
30d ago
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.
dale-cloudman
30d ago
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? :)
- "Venus: No Greenhouse Effect" https://theendofthemystery.blogspot.com/2010/11/venus-no-greenhouse-effect.html
- "Why does this simple equation predict the Venus surface temperature so accurately?" https://physics.stackexchange.com/questions/508573/why-does-this-simple-equation-predict-the-venus-surface-temperature-so-accuratel
The terminology can be tricky here. In the Fundamentals of Thermodynamics, 6th Edition (https://www.kashaninejad.com/uploads/4/6/7/6/46761445/fundamentals_of_thermodynamics__6th_edition.pdf):
This definition applies also to mutual radiation exchange between two bodies. From Gerlich 2007 (https://arxiv.org/pdf/0707.1161.pdf): "Clausius examines thoroughly, that the second law is relevant for radiation as well, even if image formations with mirrors and lenses are taken into account [178, 179].".
And from Clausius himself (https://www3.nd.edu/~powers/ame.20231/clausius1879.pdf): "Again as regards the ordinary radiation of heat, it is of course well known that not only do hot bodies radiate to cold, but also cold bodies conversely to hot; nevertheless the general result of this simultaneous double exchange of heat always consists, as is established by experience, in an increase of the heat in the colder body at the expense of the hotter."
Thus: the result of any exchange of energy as a result of a temperature difference, is that the hotter body gets colder and the colder body gets hotter: "an increase of the heat in the colder body at the expense of the hotter."
With regards to the atmosphere, the proposed greenhouse effect mechanism is thus that you have a, say, -18ºC surface in an atmosphere without any GHGs. Now, by adding CO2 to this atmosphere and thus doing nothing but changing the atmosphere's absorption and emission properties, the colder body (the atmosphere) results in a warming of the hotter body (the surface), in a tight feedback loop that essentially doubles the surface's energy level (as well as increasing the atmosphere's in the process).
To which I say: well that is not quite in direct accordance with the above sources on thermodynamics. I understand diagrams and graphs can be drawn and that the resulting steady-state is one in which the surface is still hotter than the atmosphere. But drawing a diagram does not make it so. All the laws of physics thus far have been determined experimentally, including the laws of thermodynamics.
The proof that the GHE works can only reside in an experiment demonstrating the phenomenon. There are none. There have been none since the mechanism was first proposed two centuries ago by Fourier. Do you really think the climate alarmists would not have done one by now if they could have? Rather than do so, they have simply stopped trying (if they ever did) and merely started asserting that the science is settled. Yet they skipped over that crucial experimental step! This is not science, it is ideology, beliefs, and politics.
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