CO2: Warming or Cooling or Nothing?

Fred Singer has new post on the fundamental postulate of climate alarmism as a global temperature increase of 3 C upon doubled atmospheric CO2 as predicted by climate models.

Fred starts from the poor  correspondence between climate models predicting warming and observations of no warming, and asks the question if in fact more CO2 may have a cooling rather than warming effect.

Fred then brings in the customary elements of an Atmospheric Lapse Rate ALR and an "Effective" Altitude EA for emitting Outgoing Long Wave Radiation (OLR) from CO2, and notes a warming effect if EA lies in the troposphere and a cooling effect if EA lies in the stratosphere, assuming ALR stays the same.

Altogether, Fred's discussion shows a that it is not written in stone that CO2 has a warming effect:

• Such is the power of group-think that even experts, with some exception, find the idea that CO2 might cool the climate difficult to accept.

Here the exception may include myself, even if I may not count as an expert, with message that the effect on global temperature of a bit more CO2 as an atmospheric trace gas, is not measurable. 

It thus may well be impossible to experimentally determine warming or cooling and the whole question of CO2 warming will only be of concern interior to climate models, which tell nothing about real climate.

This connects to a discussion I had with Fred in 2011 on the question:

• Can the "Greenhouse Effect" be Detected?