I have no desire to debate this. I'll refer you to wikipedia or some tree hugger website to do my argueing.
I forget the dates, but he's been there if I remember right. And even if he hasn't, some scientist has. And that scientist knows how much humans are causing global warming.
Drive all you want, this is hardly about individual citizens driving more fuel eficient cars. Its about actually electing someone into government who will do something to stop all of the pollution. More public transportation, fines for poluting, higher standards on all cars. There are a ton of things and our government is doing nothing because they are all scared of the big bad wolf that will bite them if they mention global warming.