It's a movie in the tradition of Al Gore's An Inconvenient Truth.
You can see a trailer for it here:
I have to say that I'm not really convinced that the Earth or our species are in the 11th hour, and certainly not at 11:59pm - a minute away from utter destruction or extinction - as one of those experts says in the trailer.
We just don't know enough about the Earth, its history, what's going on right now, to make such apocalyptic pronouncements.
Nonetheless, anything that gets us to think like a global community, to look at reducing the environmental problems that do beset us, to understand whether Katrinas are inevitable or avoidable, to come with ways we can all help - any movie that encourages this is very welcome.
So, while I don't agree that we're there, I look forward to seeing The 11th Hour.