Your post didn't include any references to peer reviewed research papers, and you expect anyone to believe you over the article , which did? The full text of the research paper is also available The supplementary information (which as also linked to in the article, and is listed on the pnas page) has a whole lot of statistics listed, if you think the numbers given in the article are wrong, then do the math yourself. Here's another published peer reviewed research paper: Dietary greenhouse gas emissions of meat-eaters, fish-eaters, vegetarians and vegans in the UK (full text is available, not just the abstract) Study shows that meat eating people contribute to global warming about 50% more than vegetarians, and about twice as much as vegans. It also gives environmental impact ratings for different foods, (unfortunately by kilogram rather than by calorie, so could be misleading) Bovine Meat: 68.8, Mutton & Goat Meat: 64.2, Pigmeat:7.9 Crustaceans: 5.4, Fish, Seafood: 5.4, Poultry Meat: 5.4, Eggs: 4.9 So you can make a big difference just by limiting meat consumption to pork, seafood and poultry.