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 -
How can it not have an effect, indeed?
Well, the starting point would be to demonstrate that it can have an effect, in isolated, carefully-controlled lab conditions.
That CO2 absorbs IR has been definitively shown for over a century. That this absorption and re-emission of radiation back towards a heat source causes that heat source to heat up further? Never has been, as detailed in the article.
Thus there is no experimental basis for the claim.
As to the atmosphere itself warming up due to absorbing CO2 -- firstly this is not the greenhouse effect (which is that the surface warms, not the air). Secondly, the lower atmosphere is warmed far more by conduction&convection, which 100% of the atmospheric gases participate in, than radiation, which only the IR-absorbent constituents do. Thirdly, that increased CO2 level will cause net air warming after all effects taken into account, is nowhere near certain (see: https://www.americanthinker.com/articles/2023/10/carbion_dioxide_does_not_cause_warming.html). Fourthly, the CO2 absorption is already saturated in the troposphere; any effects of additional CO2 are said to only affect higher, cooler layers of the atmosphere. Thus any effect on the surface would not be a direct effect but rather a complex, indirect effect. One might say that this means the boundary condition of the higher-up air is warmer (see earlier points if that is true), yet this comes to fifthly: the consensus is increased CO2 levels will cause the stratosphere to cool, not to warm. Thus the boundary condition at the TOA will be a cooler TOA not a warmer one.
As to differing rates of CO2 levels somehow themselves being an evidence for warming, I refer you to the article: "Looking at longer time scales calls the general theory into question: Barral 2017 shows that CO2 levels sometimes show “inverse trends” with temperature, and Easterbrook 2016 found evidence that “global warming causes increased atmospheric CO2”, and not vice-versa."
To sum: it is nowhere near as simple or certain as you claim.
Here is the absorbtion spectrum of CO2 : https://webbook.nist.gov/cgi/cbook.cgi?ID=C124389&Type=IR-SPEC&Index=1#IR-SPEC As you can see, it has low transmittance a little over 4um wavelength and between 14-16um
Compare that to the blackbody spectrum at 300K (27C, or 80F in freedom units) https://phet.colorado.edu/sims/html/blackbody-spectrum/latest/blackbody-spectrum_en.html
The emission of blackbody radiation starts at a little below 4um, peaks at 9.8um, then continues with significant emission to above 20um. so the absorbsion of the CO2 is within the ground emission spectrum.
The sun emits radiation at 5600K, much shorter wavelenght which are not absorbed by CO2, those radiation hit the ground, heat it, and the ground emits black body radiation at around 300K. that longer wavelength radiation leaves the ground. As that radiation goes up, the part of it that is within CO2 absorbtion spectrum can get absorbed. When a CO2 molecule absorbs a photon, one if it's electron gets bumped to a higher energy level, then one of two things can happen : A) the electron goes back to it's original energy level, emitting another photon in a random direction, or B) the CO2 molecule hits another molecule and the excited electron gives back it's energy to the other molecule as kinetic energy (I.E. heat). A is much more likely to happen in gases, while B is more likely in solids/liquids.
when A happens, it does not really heat the atmosphere, but it impedes the ground heat dissipation in the wavelenghts where there is high absorbtion. So if we are to keep the energy balance, what happens to the ground ? It has to increase temperature to dissipate more heat in the wavelengths that are not affected by CO2.
All of that stuff was figured out long ago in the 1800s, it's pretty baffling that people can deny it 200 years later. But I don't lose sleep over it, I took the doom pill over climate change long ago. We're fucked. even if we could magically convince everybody that we ought to do something about it, it would require a level of international cooperation that I think is impossible. How do you make all the world powers sit around a table and agree on a "let's all get poor until we figure out better energy sources" program when they can't agree on much smaller things.
and as for experimental measurement of CO2 radiative forcing, I found this paper : https://sci-hub.se/10.1038/nature14240
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