The Bush Administration has changed its stance on Global Warming. Today, the UN has released its latest report on Global Warming and there is sufficient good science in it that the conservative wing of the Republican Party can no longer deny that humans have caused Global Warming.
I say this without rancor, if that is the right word. I don't have sources for you for the following statements, but we are also tearing out rainforests in Indonesia and Brazil at such an alarming level that we are reducing the level of oxygen on the planet, not to mention eliminating potential drugs and their sources. You can read about this kind of thing in National Geographic and a bazillion other places. Or ask someone who synthesizes drugs for a living. It's true, besides living with politicians, I live in the middle of the biotech corridor. I am not a biochemist and I don't play one on TV. The head of Otzuka Pharmaceuticals lives two doors away. He has an opinion. I'm a parrot.
All of these contribute to the environment. Build a place where the animals can't live, and why would you think that we could? We're animals too.