Here is an article with data showing that the IPCC's General Circulation Models have been unsuccessful at predicting future temperature. Everyone knows this, but the politicians charge ahead with their plans to reduce fossil fuel use to "save the world." The fact that the GCMs are not competent to predict temperature does not prove that the anthropogenic global warming hypothesis is not valid, but it certainly does not prove that it is valid. I would still like to know what proof of the validity the scientists and politicians are using. So far I have only seen them cite the GCMs, which have clearly failed. I think the models have failed for a simple reason that a lot of us pointed out years ago, before it became obvious that the models would fail. That reason was that the modelers assumed that the temperature would increase monotonically with increasing CO2 levels and used fudge factors to make the models match the temperature increase from about 1975 to 1995. Thus it has been built into the models that increasing CO2 levels will increase predicted temperature. The modelers appear to have been so certain that the hypothesis was correct that they didn't even consider the possibility that it is not correct.