“An increase in low cloud cover of only about 1% could largely compensate for the doubling of CO2.” – van Wijngaarden & Happer, 2025
Ph.D physicists detail just how insignificant CO2 is as a factor in climate change, revealing that doubling the CO2 concentration from 400 ppm to 800 ppm – a 100% increase – hypothetically reduces radiative heat loss to space by just 1%.
Since CO2 has only risen by 50% since 1750 (280 ppm to 420 ppm), CO2’s total greenhouse effect influence in reducing outgoing radiation has thus far been in the range of tenths of a percentage point. A less than 1% change in outgoing radiation over hundreds of years is not even detectable amid the noise of outgoing radiation measurement. Observation error in measuring Earth’s outgoing radiation is 33 W/m², for example.
Furthermore, this negligible CO2 greenhouse effect impact is only a calculated value for an atmosphere that is perpetually cloud-free. As clouds are present 60-70% of the time, this clear-sky-only condition only occurs in an imaginary world – an atmosphere that doesn’t exist.
In contrast to CO2’s role within the greenhouse effect, the greenhouse effect of clouds is tens of times more influential. As Drs. van Wijngaarden and Happer point out in their conclusion, all that is needed to offset or wipe out the impact of doubling CO2 is a mere 1% change in cloud cover.
Since cloud cover changes of well more than 1% occur routinely, both from year-to-year and decadally, the role of CO2 within the greenhouse effect is rendered insignificant, if not irrelevant.
hmm
The conclusion (“…radiative transfer theory shows…) does not follow from anything in the paper (at least the part of the paper included here). Indeed, what this paper seems to say is that clouds bottoms are hot, clear skies, not [so much]. This is observed, not the result of theory. And it’s due entirely to WV precipitating and releasing latent heat (nothing to do with CO2).
@david dS of 2xCO2 is: dS = 5,05 * ln(2c/c) = 5,05 * ln(2) = 5,05 * 0,69 = about 3,5 W/m². This +3,5 W/m² absorption. Or if you see it as energy within the atmosphere, it is +0,9% increase to the actual 390 W/m² (288K). That’s all CO2 doubling actually can do in a clear sky with low humidity, in a physical manner. This leads to max. 1K in temperature change. Not worth to worry about, or? Any further scary changes (water vapor feedbacks) model artefacts and are empirically falsified.
br, cerm
Hmm. Your first line is hard to read, but I figured out it is the radiative forcing formula for CO2. [Query: did the 5.35 factor change to 5.05 as you suggest? I wasn’t aware of this change]
With respect I believe your subsequent analysis goes off the rails. This 3.5W/M2 value is a conceptual decrease in outgoing IR TOA. It’s not about the 390W/M2, but rather the 240W/M2 presumed to space TOA.
One cannot get to 390 W m-2 surface radiant exitance except by treating the graybody planetary surface as though it were an idealized blackbody object emitting to 0 K… clearly unphysical… because idealized blackbody objects are provable contradictions that do not and cannot actually exist… they’re idealizations, once used in a day and age before calculators and computers to make the calculations easier, now no longer needed.
The closest we can come are laboratory blackbodies, which exhibit high emissivity and absorptivity in certain wavebands, but even they are not idealized blackbodies… idealized blackbodies must, by definition, have no thermal capacity. An idealized blackbody must absorb all radiation incident upon it, and must emit all radiation it absorbs. This is why standard cavity theory is predicated upon the precondition that all system energy be in the cavity space and none in the cavity walls.
The entire “backradiation” claim is fallacious and comes about due to the climatologists misusing the Stefan-Boltzmann (S-B) equation in their Energy Balance Climate Models (EBCMs), which conjures “backradiation” out of thin air, thus the “greenhouse effect (due to backradiation)” is fallacious, thus “greenhouse gases (due to the greenhouse effect (due to backradiation))” is fallacious. Thus AGW / CAGW (Catastrophic Anthropogenic Global Warming, due to CO2) is nothing more than a complex mathematical scam.
I unwind that scam here, disproving it via multiple avenues:
https://www.patriotaction.us/showthread.php?tid=2711
The disproof is scientifically rigorous; hews completely to the fundamental physical laws; utilizes bog-standard radiative theory, cavity theory, quantum field theory, thermodynamics and the fundamental physical laws, all taken straight from physics tomes; and leaves no doubt that what the climatologists and climate alarmists claim to be happening not only is not happening, but it cannot happen… energy does not and cannot spontaneously flow up an energy density gradient, thus “backradiation” does not and cannot exist.
No, they have not ‘measured’ it… pyrgeometers and similar such equipment used to ‘measure’ “backradiation” utilize the same mis-use of the S-B equation as the climatologists do… so of course the pyrgeometers and similar such equipment are going to derive the same incorrect value… assume emission to 0 K for each calculated-upon object, isolate each calculated-upon object into its own isolated system emitting to 0 K, disconnect the interaction of objects via the background EM field via radiation pressure (ie: energy density), artificially inflate radiant exitance for each calculated-upon object by assuming emission to 0 K, carry those incorrect values through the calculation and subtract them on the back end to get the equation to balance, subtracting a wholly-fictive ‘cooler to warmer’ energy flow from the real (but too high because it was calculated for emission to 0 K) ‘warmer to cooler’ energy flow, conjure “backradiation” out of thin air, claim this “backradiation” is caused by polyatomics, choose some convenient polyatomic as a scapegoat… that’s the incorrect way the climatologists and climate alarmists do it.
If you’re curious about what actually occurs for any given change in concentration of any given atmospheric atomic or molecular species, at the link above I’ve derived the Specific Lapse Rate for 17 common gases (and included the equations so you can do the same for any others) and provided the equations so you can calculate for yourself what the effect upon the adiabatic lapse rate would be for any given change in concentration of any given gas.
That effect is one of two effects… the other: for polyatomics, a rising concentration means more emitters per parcel of air, which means a higher propensity to radiatively emit, which increases the probability that any give parcel of air will radiatively cool by emitting down the energy density gradient out to space. Conversely, a rising concentration of monoatomics and (to a lesser extent) homonuclear diatomics dilutes the radiative polyatomics, which reduces the ability of any given parcel of air to radiatively cool by emitting down the energy density gradient out to space.
IOW, the climate alarmists and climatologists, in misusing the S-B equation to conjure “backradiation” out of thin air, have flipped thermodynamics on its head… they are diametrically opposite to reality. I mathematically prove this at the link above.
Hmm, at TOA, that would mean that SW and LW radiation would be out of balance. In fact, the IPCC thinks it is measuring an imbalance there, but it is on the order of magnitude of the measurement error. So what. Vinós addresses this issue here (https://andymaypetrophysicist.com/2023/02/24/the-test-that-exonerates-co2/) (the graphic at the end of the article).
More CO2 is supposed to bring us a climategeddon, down here, 2m above sea level. But that can only happen if more IR is absorbed down here, at the source of the IR, and more thermal energy is available down here. For 288 K, 390 W/m2 are needed, 238 from SW and 152 from LW (regardless of how the distribution is assumed). 2xCO2 would add 3.5 W/m2 (or 3.7 W/m2 if you like), just +0.9% more thermal energy. What exactly does that do?
Willis Eschenbach examines the role of clouds here: https://wattsupwiththat.com/2021/09/17/uncertain-clouds/
Empirically, there isn’t much left of “IPCC: a net negative cloud feedback is very unlikely (high confidence)” and “ceiling effect”.
I’m actually not a trained physicist, only 6 semesters of undergraduate studies. But if we’re supposed to be frightened by an “all clear sky” calculation by climate “scientists” and terrible feedbacks, then I’ll pay attention…
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