I thought the best single thing was going vegan. I tried to research this a while ago, and I think the numbers work out to say that going from a "standard" Ame

I thought the best single thing was going vegan. I tried to research this a while ago, and I think the numbers work out to say that going from a "standard" American omnivorous diet to a "standard" American vegetarian diet corresponds to a CO2 emissions reduction equivalent a one-way NY-SF flight or drive. Going from that to the a vegan diet is about equivalent to avoiding the return flight or drive. So if you've already avoided having children, and already avoid flying and driving, then going vegan is probably one of the best things you can personally do to reduce your CO2 emissions. But if you haven't yet done those things, changing your diet, while a step in the right direction, may not be enough to effect a major reduction in your emissions. (Sorry for lack of references --- I'll add them up if I can find them again. They were surprisingly hard to find the first time. Corrections appreciated if I've misremembered the figures.)