The documentary An Inconvenient Truth provides a good introduction to the problem of global warming. The film has three interwoven threads: (1) a documentary showing a slide-show talk that former Vice-President Al Gore gives around the world on the facts of global warming, mixed with film footage of the impact of warming on the environment; (2) the story of Gore’s own interest in this topic; and (3) some self-promotion by Gore.
While I could have done without the last and was not particularly interested in the second, the first part was done very well. It captured most of the state of the science accurately and presented it in a visually captivating way. The film is sobering and well worth seeing to get an introduction to the science behind the problem and a sense of the gravity of the situation we are facing.