Read here. Climate experts are now coming to an embarrassing consensus that even the state-of-the-art climate models that the IPCC relies on are terrible at climate predictions, including predictions of global temperature averages. To the point, it's been announced by climate modelers that their latest and greatest climate model has "predicted" past global warming some 70% higher than what actually happened over the 150 years ending 2005.
The climate model team, Gent et al., has continued a long climate modeler's tradition of wasting taxpayer billions on climate models that are literally incapable of producing predictions that are even in the proverbial ballpark. (Overheating the world by some 70% ain't in the ballpark.)
"A paper published in the Journal of Climate announces a new version of the computer climate model most widely used by climate scientists and the IPCC...contains a remarkable admission that the model exaggerates the global warming from 1850 to 2005 by 0.4°C more than observations. The observed global warming from 1850 to 2005 was only 0.6°C, thus the computer model predicted ~ 67% more global warming than actually occurred. This exaggeration alone could account for all of the claimed "heat trapping" from the increase in man-made carbon dioxide over that same 155 year period."..."The CCSM4 ensemble mean increase in globally-averaged surface temperature between 1850 and 2005 is larger than the observed increase by about 0.4°C...This is consistent with the fact that CCSM4 does not include a representation of the indirect effects of aerosols, although other factors may come into play. The CCSM4 still has significant biases, such as the mean precipitation distribution in the tropical Pacific Ocean, too much low cloud in the Arctic, and the latitudinal distributions of short-wave and long-wave cloud forcings." [Peter R. Gent, Gokhan Danabasoglu, Leo J. Donner, Marika M. Holland, Elizabeth C. Hunke, Steve R. Jayne, David M. Lawrence, Richard B. Neale, Philip J. Rasch, Mariana Vertenstein, Patrick H. Worley, Zong-Liang Yang, Minghua Zhang 2011: Journal of Climate]
Additional prediction-failure and peer-reviewed postings.