The General Circulation Models (GCMs) used by the IPCC do not accurately model all aspects of Earth's climate, and in fact do not even include some influences. This was justified by the assumption that atmospheric carbon dioxide was the key driver, and that the other influences were insignificant. The curious assumption was also made that natural processes that had caused temperature to increase about 1 F per century suddenly stopped around 1970, and that subsequent temperature increases were caused solely by the increase in the atmospheric concentration of carbon dioxide, which causes a strong positive feedback from an increase in water vapor. With those assumptions it was only to be expected that the computer simulations would show large temperature increases in the future. Now there is some NASA research that shows that other trace gases in the atmosphere also have a significant effect. This is particularly important because the AGW hypothesis says that temperature increase will be largest at the poles. This alone has caused a lot of spin by the proponents of AGW because, while the Arctic has had some temperature increase, the Antarctic has actually been getting cooler. (There are a lot of other issues with the GCMs, such as using linearized models for a non-linear dynamic system to determine effectiveness of the natural control system, and the possible error growth in the numerical solution when extended for 100 years.)