Why the climate models keep overstating the impact of CO2

Power Line:

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Two key points here: 1) pretty much everyone agrees that the scientifically supportable consequence of doubling the CO2 in the atmosphere, a 1 degree increase in mean global temperature, would be a good thing. To get to the alarmists’ horror stories, you need to assume that increasing temperature by 1 degree would entail positive feedbacks that would quadruple that increase, or more. (This supposition seems obviously false, since in the past, when global temperatures were more than 1 degree warmer than they are today, no such feedbacks appeared.) The main positive feedback is a hypothetical increase in water vapor, which is far and away the main “greenhouse gas.” There is no basis in observation for this theory.

Further, TWTW discussed the 1997 model of the earth’s “Annual Global Mean Energy Budget” as presented by Kiehl and Trenberth paper published by the American Meteorological Society. In their graph, Figure 7, one can see the component allocated to outgoing longwave radiation and the component allocated to increasing water vapor, evapotranspiration and latent heat. Other publications disagree with the specific numbers but accept the concept.

According to the UN Intergovernmental Panel on Climate Change (IPCC) and their followers, there is a water vapor component of release of latent heat in the upper troposphere. This is the so called “hot spot,” which is assumed to be located over the tropics and strongest at a pressure between 300 to 200 millibars (mb) (roughly 9 to 11 km, 30,000 to 36,000 feet above the tropics). Over 50% of the atmosphere is below 6 km.

This “hot spot” has not been found and is not increasing as it should if the water vapor component of “CO2- caused global warming” is as strong as claimed in the Charney Report and repeated by the IPCC and others for 40 years. The recent McKitrick and Christy paper demonstrated that 60 years of weather balloon data have shown no such warming is taking place. Many other publications have likewise not found it.

If the “hot spot” doesn’t exist, the models on which global warming hysteria is based are wrong. Period.
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There is more.

Models are basically projections.  Projections are used in business to show lenders what the business expects to accomplish with new financing.  They are used for other purposes too.  When projections are not met, it is always because one or more of the underlying assumptions are invalid. 

The models projecting global warming or "climate change: have consistently overstated temperature increases and the "scientist" have been unable to explain which of their assumptions was invalid.  I have suggested for some time that it is likely that their assumption on the effect of increased CO2 is probably the problem and this seems to confirm that opinion.