Climate Change

What Would Happen If the US Went Vegan?

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There are a lot of reasons someone might adopt a vegan diet. While one person might swear off eating animal products because of moral reasons, another might because they want to improve their health or help the environment. It's true: animals produce a large portion of the country's greenhouse gas emissions, so avoiding meat and other animal products could be one way to ease global warming. A pair of researchers looked into what might happen if the entire U.S. took a stand and went vegan — and it isn't the environmental cure-all you might think.

Silent But Deadly

The U.S. agricultural industry emits about 623 million tons of greenhouse gases every year. To give you a sense of what that means, that made up about 9 percent of the nation's total greenhouse gas emissions in 2015. Producing meat also requires a lot of space and resources: to produce just four hamburger patties, it takes 55 pounds (25 kilograms) of animal feed, 270 square feet (25 square meters) of land, and 58 gallons (220 liters) of water. Just for a few burgers. What if we could all swear off meat, milk, eggs, and cheese? What might that do for the planet?

Animal sciences researchers Robin White, of Virginia Polytechnic Institute, and Mary Beth Hall, of the U.S. Department of Agriculture, decided to crunch the numbers and find out. The team designed a computer simulation that assumed a country just like the U.S. is right now, except without any animals grown to produce food and no animal-based food being imported. After accounting for the greenhouse gases currently produced by livestock, the crops currently grown for animal feed and the water used to grow them, and many other factors, they ran the simulation and analyzed the data.

Tofu 'n' Potatoes American

For how dramatic it would be to make all 325 million Americans go vegan, the study found that the environmental effects that could trigger were pretty lackluster. Even though animals make up nearly half of agricultural emissions in the U.S., an all-vegan nation would only reduce agricultural emissions by a little more than a quarter. Overall, it would reduce total emissions by less than three percent.

Why? Because raising animals and raising crops goes hand in hand. Right now, agricultural waste like corn stalks and other things humans don't eat turn into food for animals. Without animals to eat the waste, we'd probably burn it, which would send 2 million tons of carbon into the atmosphere. Planting more food crops to feed our vegan population would also require more fertilizer, and without animal manure, we'd have to make more of it artificially. That would add another 23 million tons of annual carbon emissions.

That's all before you get to the nutritional issues. Right now, it's possible to live on a vegan diet by carefully choosing plant-based foods that get you the vitamins and amino acids you need without meat. But could the entire country do the same? As White told Science Magazine, it's unlikely. "...the types of foods that seem to do that, we don't currently produce in sufficient quantities to make it a sustainable diet for the entire population." That means mass deficiencies in essential vitamins, minerals, and fatty acids.

It should be said that not all scientists agree with the team's findings. For one thing, a reduction in meat imports might reduce agricultural emissions in other countries, which the study didn't take into account. It's also possible that an all-vegan country could find a way to change the way they grow crops in order to get everyone the nutrition they need. 

This is also an extreme example — chances are slim that there will ever be enough people on a vegan diet to cause the problems this computer model proposed. Other studies have shown that even small changes in the amount of meat you consume can have a big impact on the planet. A 2016 study from Oxford University found that if everyone in the world just followed the dietary guidelines of the World Health Organization (WHO), which calls for 10.5 ounces (300 grams) of red meat per week — about half what the average American ate in 2012 — we could cut greenhouse gas emissions by nearly 30 percent. Even if a full-scale vegan revolution doesn't save the planet, doing your part in your own diet can help a lot more than you might think.

One of the most popular books about how our diets affect the planet is "The Omnivore's Dilemma" by Michael Pollan. The audiobook is free with a 30-day trial of Audible. We handpick reading recommendations we think you may like. If you choose to make a purchase through that link, Curiosity will get a share of the sale.

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Written by Ashley Hamer February 23, 2018