When I went and saw "An Inconvenient Truth" (which I strongly suggest that everyone should see). I was absolutely floored at the information provided. Jeff can probably speak about this more coherently than I, since he's working for Sierra Club, but this is what I came away with from the movie.

There are apparently NO credible scientists who dispute that global warming exists, and some 800 scientists that have written scholarly articles validating the presence of it. The loser Republicans have basically embarked on a "sow seeds of doubt" campaign without any scientific evidence to back their viewpoint, and even the losers in the Bush white house (with the exception of the top loser himself) realize that global warming is real.

The levels of CO2 worldwide have risen over the past 10,000 years (as analyzed through ice cores from the polar ice caps) almost identically to the levels of warming in the atmosphere. It isn't conclusive proof, but it's certainly a pretty strong correlation that points to CO2 production as the primary culprit in global warming. (Chad's mention was the first I'd heard of the sun putting off more energy, I will have to read more about that.)

I believe it's real, based on the evidence I've read and seen. Apparently no one (credible) has criticized the science in An Inconvenient Truth, according to research done by a major media source (I think it was NY Times or Time Magazine.) Some have said that the movie actually painted a brighter future than many scientists think is possible.

I'm also interested in what others have to say.