The food-related carbon footprint of a vegetarian is about half the food-related carbon footprint of a meat-eater.
The production of meat, particularly beef, contributes more greenhouse gas emissions than any other single food product. It also uses up more land and water and causes more environmental damage. This is largely due to the release of methane during manure management, and "the inefficient transformation of plant energy to animal energy."
A report by the EAT-Lancet Commission recommends reducing the consumption of animal products, and others have estimated that going vegetarian can cut out 25 percent of diet-related emissions.
Vegans have an even smaller food-related carbon footprint than vegetarians. New Scientist reports that the benefits of adopting a plant-based can be immense. "If those eating over 100 grams of meat a day went vegan, their food-related carbon footprint would shrink by 60 percent." Another report states that "an average 2,000 kcal high meat diet had 2.5 times as many GHG emissions than an average 2,000 kcal vegan diet."