Ben Franklin hit the nail on the head with this statement::
Climatology is a “soft science” in that it has no real predictive accuracy but is rather a bunch of models in which a person makes certain assumptions to arrive at the result they wish to achieve. It is only loosely based on measured data and known interactions. In that sense it is more akin to economics or psychology than any discipline in the hard sciences. There is simply too much that is unknown for it to be otherwise.
The fact that there is too much ‘unknown’ is the key. It seems to me the GCM’S base their conclusions on increased sensitivity of CO2 in the atmosphere which for them translates into positive feedback which would lead to temperature increase. This is an entirely unproven assumption. To my knowledge there are no countering negative feedbacks accounted for in the GCM’s . This seems highly implausible in the earth’s weather system based on the fact that the climate has warmed and cooled many times in the past, human contribution to CO2 or not. If my understanding is incorrect, will welcome an opposing explanation.
Something else to consider. The IPCC set out to prove there is AGW and according to them, they proved it
