American Thinker has a great essay with more details:
It's the Climate Warming Models, Stupid!
By Gregory Young
In addition to the difficulties mentioned above, is the late arriving Anthropogenic (man-made) Global Warming (AGW) prejudice that has set the evolution of climate modeling back a few decades. Previously known and accepted climate components have been summarily stripped from the equation -- such as the dominant factors involving the Sun and the importance of water vapor in the atmosphere as the dominant greenhouse gas. This is because in the cause to acquire lucrative AGW-biased government grants, many scientists have opted to blatantly skew their climate models to amplify AGW-favoring evidence and amplify anthropogenic CO2 importance. In this manner, they then qualify to receive funding and ensure publication.
Describing the compounded inaccuracies of these Johnny-come-lately modelers who would rather be funded than scientifically astute, Dr. Tim Ball, a former climate scientist at the University of Winnipeg sardonically clarifies: "The analogy that I use is that my car is not running that well, so I'm going to ignore the engine (which is the sun) and I'm going to ignore the transmission (which is the water vapor) and I'm going to look at one nut on the right rear wheel (which is the Human produced CO2) ... the science is that bad!"