Each day, a person who eats a vegan diet saves 4,200 litres of water, 18 kg of grain, 3 sq m of forest, 9 kg CO2 equivalent, and one animal life.

http://www.waterfootprint.org/
http://www.scientificamerican.com/article/earth-talks-daily-destruction/
http://link.springer.com/article/10.1007%2Fs10584-014-1169-1/fulltext.html
http://static.ewg.org/reports/2011/meateaters/pdf/methodology_ewg_meat_eaters_guide_to_health_and_climate_2011.pdf
https://www.amazon.com/Food-Choice-Sustainability-Buying-Eating/dp/1626524351