“From what I read the troposphere is not heating as advertised. This heating was described as a “fingerprint’. If the models get this vital forecast wrong, then what are we to believe about the rest of their forecasts?”
This is a good question.
First, the troposphere is warming as expected. It is the tropical troposphere that has not shown the warming models predict. Tropical tropospheric records are spotty at best, and it is probable, if not likely, that more data will resolve the discrepancy.
As for the tropical tropospheric warming being a “fingerprint” for CO2 warming, this is not true. The warming of the troposphere at the surface will create an even greater warming in the troposphere due to the wet (or saturated) adiabatic lapse rate. This is true of any warming at all–not just CO2. So, if the models were wrong, it means that we would need to rethink what we know about the lapse rate, especially in the tropics.
A real “fingerprint” of CO2 warming is a cooling stratosphere. This was predicted by models and theory and has been confirmed by observation.
“Is there any empirical evidence that CO2 sensitivity in the 21st century will be 3,4,5 times greater than previously observed in the 20th century?”
Empirical observations do support the models conclusions.
http://www.skepticalscience.com/climate-sensitivity.htm
