A paper published online this week in the Proceedings of the National Academy of Sciences calculates the amount of natural resources used in producing various animal products. The authors write that so far, there have not been detailed, reliable estimates of the burden that different types of animal products impose on the natural environment. Know More has previously featured an estimate from the Environmental Working Group, but that calculation was by weight and only considered greenhouse gas emissions — an important issue, but not the only environmental consequence of meat consumption. Their goal was to help policymakers and consumers evaluate their options when it comes to the livestock industry by pointing out, for example, the differences between beef and dairy products and between poultry and eggs.
Using data from several federal agencies on total production, typical feed rations, emissions, and water and fertilizer use, the authors calculated relatively how much in the way of resources it takes to produce animal products and several plant staples, per calorie. Those results are shown in the chart above. In general, animal products, especially beef, are much more resource-intensive than plant products. Pasturing cows requires an enormous amount of land, while potatoes and rice provide a high yield per acre. On the other hand, those crops also require more irrigation than do most animal products other than beef per calorie. Click below to read the paper.