A comprehensive new study finds that more than 75% of the world's farmland—an area the size of the US, EU, China, and Australia combined—could be freed up for new uses and the world still wouldn't go hungry. The big catch: Humans would have to stop consuming meat and dairy. "A vegan diet is probably the single biggest way to reduce your impact on planet Earth, not just greenhouse gases, but global acidification, eutrophication, land use and water use," says Joseph Poore of the University of Oxford, author of the Science report. His team looked at 90% of food products consumed, as grown by 40,000 farms in 119 countries, per the Guardian. Meat and dairy production provides 18% of the global population's calories, but contributes 58% of greenhouse gases, 57% of water pollution, 56% of air pollution, and 33% of freshwater withdrawals.
Depending on location, going vegan can reduce a person's carbon footprint by up to 73%, the scientists say. "You can have that impact today—not 20, 50 or 100 years into the future when it might be too late," Poore tells Newsweek. He says he hasn't consumed animal products since starting the study four years ago, and hopes taxes on meat and dairy, plus labels revealing the environmental effects, will eventually cause others to follow suit. But even cutting back could have a huge impact. Removing the most harmful half of global meat and dairy production would achieve about two-thirds of the benefits of a fully vegan population, according to the report, which finds even the lowest impact meat and dairy production causes more environmental harm than the least sustainable vegetable and cereal growing. (Livestock now account for 60% of all mammals.)