Al Gore is a money grubbing liar and all of this global warming hysteria is just that - hysteria. It's all over-hyped and is mostly nothing but fear mongering. Al Gore is only in it for the money.
If you do watch Al Gore's "documentary" make sure you also watch
The Great Global Warming Swindle.
Best line from that movie, and the bottom line: "CO2 is irrelevant".
Also be sure to pay attention to the research being done by Henrik Svensmark of the Danish Space Research Institute. His research basically shows that our climate is controlled by cosmic rays and the sun.
Cosmic rays blamed for global warming
The Chilling Stars: The New Theory of Climate Change