The debate isn't whether it's happening or not, it's if man or nature is the source. I think man has affected it, but not on a significant level. The Earth's climate changes over time, even when humans weren't on the Earth, why should we now believe that the Earth is changing because of us? I see Al Gore's movie as more of a publicity stunt/money maker more than a source of information, Al Gore isn't an expert on the subject. The Earth is changing, but humans aren't making it change, and there's nothing we can do to stop it, we have to learn to adjust.