Maybe its because scientists already claimed we were all going to die because of global cooling less than 40 years ago. I am a scientist myself, but I think predicting global weather patterns is to complicated for us to accomplish with any amount of reliability.
I do believe we should be as environmentally friendly as possible, however, I think it should be because the market wants it, not because the governments force it or because of some stupid scare that doesn't have enough factual information.