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.
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Notes -
It's a little weird that the author repeatedly denies any experimental verification of the greenhouse effect but doesn't address the 19th century experiments that first identified it. Maybe there's something wrong with his results, but you wouldn't know it from reading this post.
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.
I don't get it.
If you agree that CO2 absorbs IR, and therefore an atmosphere with more CO2 gets warmer than an atmosphere with less CO2 given a constant heat input (as far as I can tell this is experimentally verified), I don't see what there is to discuss.
The digression about how greenhouses don't work this way appears to be totally irrelevant to the question of whether the greenhouse effect exists. A rose by any other name etc etc.
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.
If the atmosphere is warmer, it seems straightforward that the ground becomes warmer than it would be if the atmosphere was colder.
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?
I don't know a thing about climate models so I can't answer your questions.
My only point is that you don't actually seem to deny that the greenhouse effect exists and is empirically verified. You seem to be quibbling about how exactly it works and how strong it is.
However, your article was very confident about the much stronger claims which you now, in my view, have walked back. In addition, you seem to evade a lot of questions in this thread and instead link various YouTube videos or otherwise unrelated content.
From this, it appears that you are in some way trying to hide the ball in this debate and therefore I have no choice but to spend many hours researching what is actually going on here or simply discount your claims as untrustworthy and going about my business. I'll go with the second option.
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."
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