The Short Summary
A plant-based diet has been shown to have a far smaller carbon footprint and use much less water and land than a typical American’s high-meat diet. A mostly plant-based diet has also been linked to dramatically improved health results, including lower rates of heart disease, diabetes, cancer, and obesity.
Carbon Footprint of Livestock
The UN report, “Livestock’s Long Shadow” from 2006 estimates that 18 percent of annual worldwide GHG emissions are attributable to cattle, buffalo, sheep, goats, camels, pigs, and poultry.
A 2009 analysis by Goodland and Anhang finds that livestock and their byproducts actually account for at least 32.6 billion tons of carbon dioxide per year, or 51 percent of annual worldwide GHG emissions. World watch says “…we believe that the life cycle and supply chain of domesticated animals raised for food have been vastly underestimated as a source of GHGs, and in fact account for at least half of all human-caused GHGs. If this argument is right, it implies that replacing live- stock products with better alternatives would be the best strategy for reversing climate change.”
The EPA says 10 percent of US emissions are from agriculture.
So the carbon footprint of agriculture, and especially livestock, seem to be poorly understood or monitored.
Water and Land Area Required by Livestock
The documentary film Cowspiracy digs into our country’s avoidance of the livestock issue. “Animal agriculture is the leading cause of deforestation, water consumption and pollution, is responsible for more greenhouse gases than the transportation industry, and is a primary driver of rainforest destruction, species extinction, habitat loss, topsoil erosion, ocean “dead zones,” and virtually every other environmental ill. Yet it goes on, almost entirely unchallenged… The popular red meat requires 28 times more land to produce than pork or chicken, 11 times more water and results in five times more climate-warming emissions. When compared to staples like potatoes, wheat, and rice, the impact of beef per calorie is even more extreme, requiring 160 times more land and producing 11 times more greenhouse gases.”
Land required to feed 1 person for 1 year:
Vegan: 1/6th acre
Vegetarian: 3x as much as a vegan
Meat Eater: 18x as much as a vegan
A person who follows a vegan diet uses 50% less carbon dioxide, 1/11th oil, 1/13th water, and 1/18th land compared to a meat-eater.
“Sustainability of meat-based and plant-based diets and the environment.” The American Journal of Clinical Nutrition, 2003.
Oppenlander book: Food Choice and Sustainability: Why Buying Local, Eating Less Meat, and Taking Baby Steps Won’t Work
Health Effects of Meat-Rich Diets
The documentary film “Forks Over Knives” details many reasons to cut back on meats.