Beef is extremely inefficient to produce, as cattle consume a huge amount of calories and protein in order to produce a relatively small amount of calories and protein for human consumption (sheep and goat are similarly inefficient converters of feed to food, but are eaten on a much smaller scale globally). As a result, beef production requires large quantities of land and water per unit of protein or calorie consumed.
One-quarter of the earth’s land (excluding Antarctica) is used as pastureland, and beef accounts for one-third of the global water footprint of farm animal production. Beef also has a disproportionate impact on climate change. Ruminants, of which cattle are the most common, accounted for nearly half of all agricultural production-related greenhouse gas emissions in 2010. If cattle were able to form their own nation, they would rank third behind China and the United States among the world’s largest greenhouse gas emitters.The average American could cut their diet-related environmental impacts by nearly one half just by eating less meat and dairy. Working with the French agricultural research institutions CIRAD and INRA, we modelled the effects of several diet scenarios. When applied to the average American diet in 2009, the ambitious animal protein reduction scenario (which cut people’s meat/dairy/fish/egg consumption in half) reduced per person land use and agricultural greenhouse gas emissions by nearly one-half—or almost as much as the vegetarian scenario (which eliminated meat and fish, but increased dairy consumption relative to the average American). The beef reduction scenarios reduced per person land use and greenhouse gas emissions by 15 percent (replacing one-third of beef consumption with other meats or legumes) to 35 percent (reducing beef consumption by 70 percent, down to the world average level).