I just saw Leonardo Di Caprio's film "the 11th Hour." I was actually disappointed in it, even though it had a lot of information. Maybe I just didn't like the style; talking heads of some kind of organization you've never heard of mixed in with 5 second blasts of interesting but disjointed videos of environmental stuff. Al Gore's "An Inconvenient Truth" was mostly just Al standing there talking with some powerpoint thrown in, but I think it provided more useful information. "The 11th Hour" attempted to smash too much unsubstantiated (I don't think talking heads = proof) information into too little time and thus actually gave less.
Nevertheless, I think someone on the fence about the environment would have been swayed to see that something not only needs to be done, but can be done.
If I had made the movie, I'd have just had the biggest experts in simple terms explain the problem and how definitive it is (15 minutes) , then cover things that can be done (an hour), and then HOW we can get there from here (15 minutes).