As part of a recent study, a research team in the US assessed how much land, water and nitrogen fertiliser was required to raise different kinds of produce, including beef, chicken, pork, eggs, and dairy. Led by Gidon Eshel, professor of environmental science at Bard College in New York, the study was based on data collected between 2000 to 2010 by the US Departments of Agriculture, Interior and Energy.
The results, published in the Proceedings of the National Academy of Sciences today, show that cattle require on average 28 times more land and 11 times more irrigation water than pork or chicken, and six times as much nitrogen fertiliser as egg or poultry production. This adds up to the statistic that beef production releases five times more greenhouse gases than anything else.
While it was already known that beef production is having a pretty significant impact on the environment, this new analysis has quantified the damage in relation to other options to find out what we should be eating more and less of, environmentally speaking.
Lamb and fish meat were not included in the study because US consumption of both is relatively low.
The key to beef’s hefty environmental impact is that cattle are far less efficient at getting the most out of their food than pigs and chickens are. “Only a minute fraction of the food consumed by cattle goes into the bloodstream, so the bulk of the energy is lost,” Eshel told Damian Carrington at the Guardian, adding that feeding cattle grain rather than grass makes this inefficiency even worse.
While the research doesn’t mean you have to give up your beloved steak, it does offer a pretty effective way to reduce your carbon footprint - simply cut down on your consumption of it. "The biggest intervention people could make towards reducing their carbon footprints would not be to abandon cars, but to eat significantly less red meat,” said Tim Benton, the UK Champion for Global Food Security at the University of Leeds to the Guardian.
A good ballpark, as recommended by the Australian Department of Health, is sticking to 65 grams of cooked red meat per day, which is 90 to 100 grams of uncooked meat. If the average steak is between 200 and 350 grams, this means sticking to a steak and a half per week. As an extra incentive, not only will the environment thank you, but according to the Conversation, this will significantly reduce your risk of contracting bowel and stomach cancer.