When I was initially thinking about my personal impact to this, the first thing that came to mind is air-travel. I don't travel much, maybe once a year to see family. I have some friends who fly several times a year to "see the world", being well-traveled is a part of their personality. But I think I may be wrong on flight being a significant contribution. My guess is that we probably all contribute to this mainly through our SP500 index investments, which financially supports a number of companies that directly contribute to global warming. We're "voting with our dollars" as they say. Maybe we can all start picking individual stocks based on environmental values/promises, and less short-term gain. Somehow, I don't think it'll happen.