Roughly 90% of all published scientists, regardless of their field, believe that humans cause global warming. To make things even worse for deniers, 99% of published climatologists -- the experts in this field -- believe the same thing.
Of course, the media -- obsessed with a phony "objectivity" -- gives equal time to nutjobs. So the next time you see a talking head show, you'll see one reality-based head and one denier head arguing, creating the impression that the scientific community is split on the question along a 50/50 line.
But to accurately represent the scientific community in general, there would have to be nine reality-based heads to one denier. Among climate scientists, the breakdown would be ninety-nine scientists who believe in human caused warming to one lone nutjob who thinks it's all a crock.
I feel pretty safe in concluding that the opinion of 99% of all climatologists represents the consensus position. It's not the science behind global warming that's a crock, it's the idea that there's a serious debate about it; that's just a lie. Among climate scientists, the percentage is high enough to legitimately call the debate over.