think positive - think climate change, page-17

I love science, and debate this a lot with friends and family. It can get quite heated (pun intended :P)

One piece of evidence often overlooked is the fact that Greenhouses are needed in the agricultural industry for optimal plant growth, with near 1000ppm C02 needed. What does this say about our atmosphere, where it is some 395ppm?

Also, imagine if, instead of polar icecaps, we had rainforests in their place like was the case hundreds of millions of years ago when everything grew to enormous proportions? Who says polar icecaps are a necessity for our planet when Earth has been without them in the past?