It turns out that if you are a self-described liberal, your certainty about anthropogenic global warming increases as you become more scientifically literate. However, if you are a self-described conservative as you become more scientifically literate you become more certain that whatever global warming is occurring is not due to human causes.
Now, the author of the linked blog post says this might be because values drive how interpret empirical things.
I've seen it elsewhere said else where that what the study mentioned in the link shows is that conservatives are close-minded. It's almost like the people elsewhere are trying to prove the study true....