Are you aware that nearly half of all the water usage, 1/3 of all fossil fuels, and 80% of all agricultural land in the USA goes to the production of animal products? It's an incredibly wasteful industry, especially considering that we have to grow most of our crops just to feed those animals. You actually save more water by not eating a pound of beef than by not showering for an entire year, not to mention all the other resources consumed and the pollution and waste production. Consequently, I don't think it's an exaggeration to say that a non-vegan environmentalist is an oxymoron. (If you want to peruse a good source for such stats and details, The Food Revolution is a great place to start.)
I did not realise just how bad it was.