A very interesting discussion about the foibles of climate modelling.  Here is but a taste:

A major thrust of the debate was because Schlesinger had put the same data into the five models and each produced results that he claimed were meaningful. Somebody pointed out that the results differed considerably from model to model. For example, they differed by 180° in their predictions for large areas. Schlesinger’s reply was the models were not accurate for small regions. The person pointed out that the small regions were continental in their dimension. Much laughter at this point. Schlesinger then said the models were not quantitatively correct but they were qualitatively correct. When asked to explain what he meant he said well they all showed global warming with increased CO2. It was quickly pointed out that if you program them to have temperature increase with a CO2 increase (ceteris paribus) then that was an inevitable result of the programming not the reality. The noise volume increased at which point a bizarre incident occurred.

During Schlesinger’s presentation, titled, "Model projections of the Equilibrium and Transient Climatic Changes induced by Increased Atmospheric CO2" there were general rumblings in the audience about the nature and assertiveness of the presentation, something that I had come to know as normal for modelers. This erupted in the question period. However, prior to that there were strange noises coming from behind me. I did not want to look around based on my experience at english soccer matches. In the question period voices were raised and frustrations expressed about the inadequacy of the models. Suddenly at the height of the din a shoe flew upon to the platform from behind me. There was shocked silence and a strange voice said, "I didn’t have a towel." He then asked permission to go onto the platform. It turned out the strange noises were from the shoe thrower who had a voice box. He explained he had two Ph.Ds one in Atmospheric Physics and proceeded to put a formula on the blackboard. Schlesinger agreed it was the formula for the atmosphere at the basis of his models. The man then eliminated variables one at a time, each time having Schlesinger agree he eliminated them from the final model. The man then said what you have left no longer represents the atmosphere and any results from such as model were meaningless.