CO2 Climate Sensitivity Vs. Reality

Anyone who has followed the climate debates on the internet knows that even most "skeptics" of runaway global warming (and all of those who ever make the news or have a large audience on their blogs) accept the consensus "greenhouse effect" and the idea of a "CO2 climate sensitivity", or theoretically expected global mean surface temperature (GMST) increase with increasing atmospheric carbon dioxide (CO2--due, everyone is brainwashed to believe, in increasing fossil fuel consumption by man). Anthony Watts has posted yet another article by one of his fellow-believers, arguing for a significant value of the CO2 climate sensitivity (albeit smaller than that claimed by the alarmist climate scientists). The following is my response, to any who are still capable of thinking for themselves on the subject, and who want definitive, quantitative proof of the truth of the matter.

Anyone who wants to keep worrying about the "CO2 climate sensitivity" needs to explain why, in the Venus/Earth temperature comparison I performed well over 2 years ago, there is none at all: Venus has 96.5% CO2 to Earth's less than .04%, yet the Venus/Earth temperature ratio is a constant due entirely and precisely to the ratio of their distances from the Sun and nothing else (no "greenhouse effect" contribution, no "difference in planetary albedo" contribution--no anything but the difference in the solar distance).

The precision with which the solar distance, by itself, explains the Venus/Earth temperature ratio--at points of equal pressure, over the range of Earth tropospheric pressures--is nothing short of amazing, in the present tattered intellectual climate, in which the greenhouse effect is adamantly, vehemently claimed to be "settled science", and even most "skeptics" smugly argue for SOME CO2 climate sensitivity. But the Venus/Earth comparison says that smug certainty is a lie, and there simply is no greenhouse effect, of increasing temperature with increasing atmospheric carbon dioxide, AT ALL.

If one is dense enough, after studying my Venus/Earth analysis, to demand what that analysis shows the CO2 climate sensitivity to be, here is what it says:

First, for over half of the range of Earth tropospheric pressures (between ~650 - 250 mb), the Venus temperature is COOLER, by about 5°K, than is predicted from the solar distances alone. But as indicated in my original analysis, in this pressure range lies the thick planetary cloud cover of Venus. Below that range--between 1,000 and 700 mb--the temperature ratio is essentially just that predicted from the solar distances alone; above the cloud layer as well (at 200 mb), the ratio again comes back to very near the "solar distances only" prediction, though not quite all the way (the Venus temperature there is only ~1.7K cooler than so predicted)

The best estimate of the climate sensitivity to changes in CO2 alone, then, is made with those points below the Venus cloud layer. For the 4 points in that pressure range, in my original analysis, the Venus/Earth temperature ratio varies between 1.172 (at 800 mb) and 1.178 (at 1,000 mb), with the average being 1.175.

(The uncertainty in that measured ratio is just the uncertainty in the Venus temperature (1.4K) divided by the corresponding Earth temperature (average 278.3K, for those 4 points), or +/-.005.)

Now 1.175 is just .001 less than the 1.176 predicted by the solar distances alone, and since that error is much less than the +/- .005 uncertainty, it should be immediately obvious that there is no greenhouse effect, without even bothering to calculate a "CO2 climate sensitivity". But let's do so anyway. That .001 "error" in the temperature ratio gives a possible error of only .001 x T_earth, or about -.3K, from the Venus temperature predicted by solar distances alone (that is, using 1.176 for the ratio). If one assumes that -.3K difference is due entirely to the "CO2 greenhouse effect", then the maximum CO2 climate sensitivity (in degrees K per doubling of CO2) is -.3K divided by the number of doublings, between ~353 ppm on Earth (in October 1991, when the Venus data was obtained) and 965,000 ppm (96.5%) on Venus--which is 11.4 doublings of CO2, so that -.3K/11.4 = -.026K/doubling of CO2, or about -.03K/doubling (a slight negative number, note), for the CO2 sensitivity.

But with an uncertainty of +/- 1.4K in the Venus temperature (see my original analysis), the uncertainty in the CO2 climate sensitivity is +/- 1.4/11.4 = .12K/doubling.

So my Venus/Earth comparison demands that the CO2 climate sensitivity must be less than

( -.026 +/- .12) K/doubling

and since the indicated sensitivity is much smaller than the uncertainty, the CO2 climate sensitivity revealed by my Venus/Earth comparison must be reported as

essentially zero (0),

...which is just a precise quantitative statement of the fact that has been obvious all along, that the Venus/Earth comparison shows there is NO greenhouse effect, period. Only solar distance counts in the detailed comparison of these two vastly different planet-plus-atmosphere systems. And the physical reason is because both atmospheres are fundamentally and globally warmed in precisely the same way: by direct absorption of the same physical fraction of the incident solar energy (and NOT from the planetary surface, as almost everyone--and certainly every mis-titled "expert"--believes is the case on Earth).

Added Note: In the above, there are in fact three different, but equivalent, quantitative statements to demonstrate that there is no greenhouse effect of increasing temperature with increasing CO2:

1) The error between measured Venus temperature and that predicted from Earth's Standard Atmosphere and the smaller solar distance of Venus = (-0.3 +/- 1.4)K,

2) The error between measured and predicted Venus/Earth temperature ratio = -.001 +/- .005,

3) The possible size of the CO2 climate sensitivity = zero (-.026 +/- .12)(K/doubling of CO2)

In all three quantitative statements, the (+/-) uncertainty is about 5 times the error, indicating the error is entirely negligible