CO2 is a natural part of our enviroment but the bad thing is the huge amounts we are producing these years. Forest fires produces huge amounts of CO2, much more than your average automobile but the isue is the amounts of cars! We (The human race) are responsible for a huge increase in the CO2 amount on planet earth, I don't think anyone can disagree with that. Just look at Tokio, people have to wear masks to breath - that cannot be good!
I believe we should be careful not to overlook how big a factor we can be to our enviroment.

Originally Posted by: sgreggin every conceivable measurement, the major industrial nations of the world are much cleaner and more environmentally sound than we were even ten years ago.

I don't know where you get that from but I do find it hard to believe. The air can't possible be cleaner when we have millions of engines burning oil everyday. It must have some inpact!!