In April, the Intergovernmental Panel on Climate Change dropped a gargantuan report examining how humans might mitigate the worst impacts of climate change. The entire report runs almost 3,000 pages, but the bit you really need to know about comes 50 pages in and lists all the ways we can reduce emissions right now.
Switching to wind and solar energy are listed as the two highest-impact shifts. But a little lower down there’s an odd one: “shift to balanced, sustainable healthy diets.” If that phrasing strikes you as mealymouthed, that’s because it is. An earlier version of the report included a recommendation that people switch to plant-based diets, according to a report from Reuters. But this advice was watered down in the negotiations after lobbying from the US, Brazil, and other countries with large meat industries. In the executive summary, plant-based diets are relegated to a single mention: a footnote on page 43.
But you can’t talk about food’s climate impact without talking about meat. Food production accounts for around 26 percent of all global greenhouse gas emissions, and the biggest chunk of that comes from livestock. The highest emissions come from ruminants like cattle and sheep because of the way they belch up methane as they digest food. Per gram of protein, beef has eight times the greenhouse gas emissions of chicken and 25 times that of tofu. The impact on land is huge, too. Almost 80 percent of all agricultural land is used as pasture or to grow crops for animal food, and the expansion of pasture for beef drives 41 percent of annual tropical deforestation.
Yet it turns out putting even a modest dent in our rapacious desire for beef could have big environmental benefits. Swapping just a fifth of our beef consumption for a mycoprotein like Quorn could dramatically slow the pace of future deforestation. A new study in the journal Nature modeled what would happen if people swapped out beef or other ruminant meat in their diet for mycoprotein—or continued on our current trajectory. In a world where demand for beef kept going up, deforestation rates would more than double. But if people swapped 20 percent of their beef for mycoprotein, deforestation rates by 2050 would be half what they would be if beef consumption continued to rise as projected.
“Part of the solution to this problem could be existing biotechnology,” says Florian Humpenöder, a researcher at the Potsdam Institute for Climate Impact Research in Germany and the lead author of the Nature paper. Other scientific studies have advocated for much bigger reductions in meat-eating. The EAT-Lancet Commission, for example, recommends that people eat no more than 98 grams of red meat (pork, beef, or lamb) per week—a little less than a single quarter pounder. The average American eats almost seven times that amount of beef alone.
For Humpenöder, a 20 percent reduction in beef consumption seemed like a more realistic goal. “Reaching a substitution share of 20 percent by 2050 sounds somewhat achievable to me. Or at least not super-optimistic,” he says. He also ran two other scenarios in which mycoprotein replaced 50 and 80 percent of beef consumption by 2050. In these two scenarios, deforestation and associated emissions were even lower. Each of these shifts roughly halved the projected deforestation rate, but the biggest gain was from the relatively small substitution of 20 percent of beef with mycoprotein.