The food we eat has some kind of environmental cost – usually in the form of land to grow the food, water, fertilizer and pollution due to the machinery used. We tend not to think of which foods have a greater impact on the environment – growing crops requires land, water and (often) fertilizer. And it is easy to see how meat would incur a greater environmental cost – first we need to grow crops to feed the animals, then we need to provide additional water and land. But how much greater is the environmental impact of eating meat compared to plants? Further, how do meat sources compare in their environmental impact?
In a recent paper, Eshel et al. (Eshel et al., 2014, PNAS 111:11996–12001) compared the environmental impact of various animal food sources. They used a standardized method to compare dairy, beef, pork, poultry, and eggs in the United States. On the whole, Eshel et al. found that the animal-based portion of the American diet uses 40% of the US land area, water use is comparable to that of the American population, half of fertilizer use goes to animal food sources, and 5% of American greenhouse gas emissions are due to producing food from animals. The main conclusion is that beef production uses far more resources than the other major animal protein sources, which are generally equivocal in their resource requirements (see graphs below).
Clearly reducing beef consumption could have a significant impact on reducing the environmental impact of one’s diet. On further analysis, Eshel et al. find that beef uses 160 times the land as crops do per calorie produced. It is then interesting to note that simply eliminating beef from your diet, without giving up meat consumption, can still dramatically reduce your environmental footprint.
The article from Eshel et al. outlines how important it is to determine all resource requirements of a food source in a comparable manner, to inform us as to how we can reduce the environmental impact of our diet. This in turn can help to increase the sustainability of our agricultural systems moving forward.
Stay safe and stay informed,