Cows are a heavyweight in the climate conversation. The livestock industry makes up almost 15% of the world’s greenhouse gas emissions, two-thirds of which comes from bovines raised for beef and dairy.
A big reason? The digestive process in ruminants like cows, sheep, and goats, known as enteric fermentation. Cows have a multichambered stomach, and one compartment is home to microbes that break down tough plant matter. This causes cows to burp—a lot. Every year, one bovine can belch 220 pounds of methane, and the whole global herd produces around 30% of the world’s human-made methane—more than the energy sector, waste, and biomass burning. Methane doesn’t stick around in the atmosphere as long as CO2, but over 20 years, it traps over 80 times the heat.
With four years left to hit the Paris Agreement’s goal of limiting warming to 1.5 degrees, global leaders agree that cutting back on methane is a make-or-break opportunity. But with Americans demanding more meat than ever and becoming increasingly hesitant to give it up, researchers are turning to science in hopes of creating climate-smart cattle. But is it enough? Let’s get into it.
What a low-methane cow could look like
Researchers and companies have increasingly embraced the idea of low-methane cows, experimenting with solutions from masks to methane-inhibiting feed additives. One oft-discussed way involves bromoform, a compound found in seaweed like Asparagopsis and sugar kelp, which disrupts cows’ digestive systems. Such naturally derived additives have varying levels of success, gaining support from fast food giants like Chipotle and billionaires like Bill Gates. Synthetic additives like Bovaer claim to reduce methane emissions in dairy cows by 30% and 45% in beef cattle on average. In April, a study published in the Journal of Dairy Science found flaxseed and pea protein can help cut cows’ methane output.
A methane-free cow could also start at the genetic level. Some scientists have floated vaccines that target the emitting bacteria in cow guts or selectively breeding lower-emitting livestock. And there’s no dearth of money for those keen to find a clean-burping bovine. The Bezos Earth Fund announced $19 million in funding toward both developments in April.
Potential––or potential greenwashing?
With all this going on, where’s the methane-free beef? There are two major issues. First off, these technologies don’t completely nix the potent gas. Ermias Kebreab, professor and Sesnon Endowed Chair in the Department of Animal Science at UC Davis, expects methane reductions of 20% to 30% at scale using technologies like Bovaer or seaweed-based additives—potentially more with genetic improvements. Still, there’s no data on the books yet to show that these interventions don’t affect animal health, productivity, or the environment through residues or emissions trade-offs. There’s also the challenge of getting enough vaccines and/or additives to places like Brazil, China, and the European Union, which trail closely behind the U.S. as top beef producers. “Deploying these solutions in low- and middle-income countries is challenging due to cost, access, and regulatory hurdles,” he says. “But the impact could be transformative.”
Burps are also just one part of the equation when it comes to livestock’s climate footprint. Critics point to the trade’s sprawling supply chain: Land-clearing for cattle feed and farming drives at least 40% of tropical deforestation and the energy efficiency of beef sits at a mere 1.9% (meaning 98.1% of cattle feed inputs are lost when they’re turned into animal products). “Mitigating methane emissions alone won’t offset the broader climate impacts of land-use change,” Kebreab says. “If low-methane cattle are raised in systems that still drive deforestation or rely on high-impact feeds like soy from cleared tropical land, the net environmental gain may be minimal or even negative.”
The best path is not either/or
For Kebreab, methane mitigation must be part of a broader strategy that includes stopping deforestation, improving efficiency, and adopting sustainable land management. But another key component is making the public aware of beef’s impact so that they can make informed decisions—including eating less of it.
According to a study published earlier this year in Food Policy, consumers preferred low-methane beef products once they were made aware of the difference. But, to dig deeper, American adults who are open to dietary change could axe their food-based emissions by 40% if they traded beef for plant-based proteins.
Big Beef doesn’t want folks to know that. Instead, giants like Tyson Foods are playing into dreams of “green beef.” They market products as “climate-smart” to boost sales despite lacking data to support such claims and face lawsuits for misleading consumers.
While we’re waiting for these emerging solutions to scale, the most immediate, results-guaranteed way to shrink our food-related methane footprint is simple: reduce our demand for beef and dairy products. “The best path is not either/or, but both: shifting diets and transforming production to meet nutritional needs within planetary boundaries,” Kebreab says.