U.K. TV Channel 4 broadcast an excellent documentary covering the whole manmade global warming scare. It is available for viewing on line at:
The Great Global Warming Swindle
I watched it and it's a well done documentary. Check it out if you can. It runs about 1:15 minutes.
If you don't have the patience, at least read this column about it.
Calgary Sun: Debunking Global Warming Myths