This blog has been highly critical of the computer models that are used to forecast future climate. A review article, just out, says:
There should be little confidence in climate models. The model simulations fail in their attempts to provide credible quantitative estimates of future climate change, on regional, or continental, or global scales. The models have shown little to no ability to reproduce observed features of current climate and past climate changes. Confidence in model estimates is greatly overstated by the IPCC for the most common of climate variables (e.g., surface temperature) used to present the supposition of manmade global warming.
Undoubtedly, climate models will begin to show skill at some point in the future. But, at this point, there is no reason to give them any credibility.