[91chevywt]

I still don't think there is enough evidence to prove it is at the fault of human beings for "global warming." The earth goes through heating and cooling cycles throughout its life, whos to say thats not whats happening. Theyre all theories. There is a theory that the elevated levels of CO2 comes as a by-product of the overall warming of the earth but you won't hear about it in the news.

That being said, I still think it is important to keep cars clean. Pollution down at the ground level is totally different from CO2 in the atmosphere. Breathing in Carbon Monoxide and Hydrocarbons is not something we should go back to. Cars are the cleanest they have ever been and making nice power to boot