I don't think that al gore giving a global warming speech at the kickoff of the movie Day after tomorrow is a good idea for the greens.
People don't associate Hollywood with reality. A movie is fiction, and when ever you bring up stuff that happens in movies you are treated a bit differently. "Hey did you see those aliens last night?" does not occur in normal conversation among Americans.
When ever someone mentions global warming they are going to think the Day After tomorrow. If that is what the greens really want, that is fine with me. Making pretend movies and then jumping on the bandwagon trying to educate people before the movie is a bad idea, and does not help people to take you seriously. Although, given the context of the movie I would have assumed that it was a right winger under cover , and that it was the right winger's goal to make fun of the left.
Edit: Twister is based on real life events, but people would look at you like you were crazy if you said twister could really happen, and we must do something about it. And I think that this will be the same reaction the greens get from normal society.