How can we, as WEIRD (Western, Educated, Industrialized, Rich, and Democratic) individuals, mitigate our catastrophic effects on the environment? Pretty much all recommendations start with this: eat less meat.

Like the other top recommendations—drive less and fly less—this is not super appealing to most of us. But beef production in the US uses more land, water, and fertilizer than any other form of agriculture, no matter which way you cut it. Whether you measure by calories or grams of protein generated, cows are the elephant in the room.

As of now, cattle eat not only local pasture, but also grains, hay, and grass that is grown elsewhere and stored. A recent analysis by an international team of researchers looked into what would change if the US switched to sustainable ranching, in which cattle eat only from local grasslands and agricultural byproducts.

It turns out that the current amount of pastureland in the US could only support 45 percent of our current beef production and consumption. This admittedly narrow definition of sustainability relies on feeding cows more agricultural byproducts, which, as of now, account for only about 10 percent of their diet; the scientists note that, “despite the recent doubling of distillers’ grain utilization,” these byproducts are still plentiful.

If we were to cut the pastureland that ranchers currently use in half, that would diminish beef availability to... 43 percent of current values, rather than 45. So freeing up about 135 million hectares—almost a quarter of our national surface area, and twice the size of France—would decrease beef availability by only two percentage points.

Most of this is not especially productive grassland, and it could be rewilded or conserved. But some of it is high-quality cropland that could be used to grow other food sources, like pork, poultry, grains, legumes, vegetables, and even dairy. All of these utilize less water and fertilizer than beef while emitting fewer greenhouse gases. In addition, they provide us with more calories, fiber, micronutrients, and even protein than the beef they’d supplant. The only thing we’d be missing is vitamin B 12 , for which the authors of this analysis offer a quick fix: take a pill.

They conclude that “If Americans reduced their mean beef consumption from the current ~460g per person per week to ~200g per person per week, the US beef industry could become environmentally sustainable by the narrow definition of this paper.” Easy. Just have one weekly burger instead of two.

Nature Ecology and Evolution, 2017. DOI: 10.1038/s41559-017-0390-5 (About DOIs).

Correction: fixed missing order of magnitude on hectares.