Global warming

I believe that global warming is something that was man's own mistake. Because we have so many factories, and cars spitting out CO2 into the air, we have damaged our own atmosphere! Alot of people think that "Oh it's not that big of a deal!" but, at one time, the Earth's atmosphere was all CO2, now it's all O2. But do you really want to go back? Do you really want to live in a world where your'e breathing in what you normally breathe out?? And also what about all those species of animals that are dying out!! The ice caps are MELTING