I just came across yet another person in an online forum saying “The single best thing the average U.S. resident can do to help the environment is become vegetarian/vegan.” When looking for a citation better than my own vague ruminations, I found this excellent page:
Their numbers are pretty close to mine! Also, notably, those pie charts confirm what I’d suspected: that the real issue is not meat, but beef. The footprint of a beef-avoiding carnivore is shown as 1.9 tons/year, only .2 tons higher than the 1.7 tons assigned to a vegetarian.
And, it remains clear that diet is pretty small potatoes compared to heat and travel.