Read here, starting page 23. We have written multiple times about the failures of climate models. Politicians and the mainstream press are in love with climate models because they can be used to proffer scary "scientific" predictions to influence the public regarding global warming. Climate alarmists scientists find the climate model predictions a convenient way to help them raise additional research funds. As has been well documented though, climate models are absolutely worthless regarding accurate climate predictions.
Below is an example of wildly different predictions of two climate models. These are predictions of rainfall change across 18 regional areas by the year 2090. This is the typical, non-consensus output one sees when comparing "state-of-the-art" climate models. (click on image to enlarge)