New research compares environmental costs of livestock-based foods
Trust me, no one loves a nice, big, juicy steak more than me and while I have no immediate plans of becoming a vegetarian, I am a little concerned about the resources and costs it takes to produce the proteins of our favorite meals. From the land that is used by livestock to the supplies and energy it takes to raise these animals for our consumption, it is evident that environmental resources take a toll. But what is the real cost?
New research at the Weizmann Institute of Science, conducted in collaboration with scientists in the US, calculates these environmental costs and compares various animal proteins to give a multi-perspective picture of what resources are really being used.
The team looked at the five main sources of protein in the American diet: dairy, beef, poultry, pork and eggs. Their idea was to calculate the environmental inputs — the costs — per nutritional unit: a calorie or gram of protein.
The inputs the researchers employed came from the US Department of Agriculture databases, among other resources. The environmental inputs the team considered included land use, irrigation water, greenhouse gas emissions, and nitrogen fertilizer use.
When the numbers were in, including those for the environmental costs of different kinds of feed, the team developed equations that yielded values for the environmental cost for each food.
The winner? Or should we say, the protein with the biggest footprint? Beef. Which does not come as a surprise. Researchers calculated that in total, eating beef is more costly to the environment about ten times on average — than other animal-derived foods.
Why? For one, cattle require on average 28 times more land and 11 times more irrigation water. They are responsible for releasing 5 times more greenhouse gases, and consume 6 times as much nitrogen, as eggs or poultry. Interestingly, poultry, pork, eggs and dairy all came out fairly similar. Dairy production is often thought to have low environmental impacts, however, that the price of irrigating and fertilizing the crops fed to milk cows — as well as the relative inefficiency of cows in comparison to other livestock — jacks up the cost significantly.
Besides changing the way we think about our diets, researchers hope this study will help inform agricultural policy. Models based on this study can help policy makers decide how to better ensure food security through sustainable practices.
The findings are published in the Proceedings of the National Academy of Sciences (PNAS).
Read more at the Weizmann Institute.
Meat image via Shutterstock.