I'm sure humans can have a negative effect on the environment, that's obvious. But there have been much more dramatic climatic changes in the earths history than the fractions of degree differences that we;re seeing now. Be smart about the environment, but don't panic like it's the end of the world. Sheesh. I would bet my life, that with the longer life expectency of humans, we'll have far over populated the world before it ever gets too hot to live here. And then what do we do? Join together in mass suicides to help the earth? There are bigger issues to worry about.