Five cows stand on the horizon with their back to the camera.
Joanna Foster 6 minute read

Farmers, scientists seek solutions to global warming caused by cows

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The Crave Brothers Dairy in Waterloo, Wisconsin, is famous for its fresh mozzarella, squeaky cheese curds and creamy chocolate mascarpone. 

But that's not all they produce here. 

The dairy’s more than 2,000 milking cows also help generate enough electricity to power the entire farm, cheese factory and 300 local homes.

The miracle of cow poop power derives from two massive anaerobic manure digesters that capture the methane released as the manure is processed into liquid fertilizer and bedding material for the cows.

“It’s not always sunny or windy here, but we definitely always have manure,” says Karl Crave, part of the third generation of Crave family farmers. “We like to call it cow power.”

Across the country, there are more than 300 anaerobic digesters like the ones on the Crave Brothers dairy. They are helping farmers diversify their businesses while reducing planet-warming methane emissions. 

Man walking with cows in front of farm buildings with American flag flying
The Crave Brothers Dairy in Waterloo, Wisconsin.  (

Methane is a climate problem  

Methane is an extremely potent greenhouse gas, with more than 80 times the warming power of carbon dioxide in the short term. It is expected to cause half the warming we’ll experience over the next two decades.

Anerobic digester diagram
The anerobic digester at Crave Brothers Dairy.  (

And there's no sign of relief. According to the National Oceanic and Atmospheric Administration, global methane emissions increased last year by the largest amount since measurements of greenhouse gases began in 1983.

Globally, agriculture is the largest source of human-caused methane emissions. And in the U.S., agriculture is responsible for about one third of total methane emissions. That’s on par with the oil and gas industry. 

“On farms, you’re dealing with intricate biological systems, not a leaky pipe,” says EDF lead senior scientist, Joe Rudek. “For the oil and gas industry, methane is a valuable product being lost, so there's a financial incentive.”

Global problem, global action

In fall 2021, more than 100 governments pledged to cut methane emissions by 30% by 2030, as part of the Global Methane Pledge, launched by the EU and the U.S. 

In was an historic moment. But the world can’t meet this crucial goal without dramatically reducing the methane released on farms, an obstacle that until very recently seemed technically and politically insurmountable. 

Now, thanks to innovative strategies for reducing agricultural methane and growing support from farmers and businesses, there is new hope for progress. 

Recently, in the first ever methane-specific climate commitment by a major food company, one of the world’s largest dairy companies, Danone, pledged to reduce agricultural methane emissions from its fresh milk supply 30% by 2030. The pledge builds on the progress Danone has already made, reducing its methane emissions by around 14% between 2018 and 2020. For dairies, about 43% of methane emissions come from manure.

Tackling methane emissions from cows

Livestock — primarily beef and dairy cows — account for the vast majority of agricultural methane emissions. And there are a lot of cows: More than 94 million in the U.S. and around one billion globally. Cows produce methane in two ways: from the decomposition of their manure under certain conditions, and by what is politely known as enteric emissions — cow burps.

“Addressing methane from livestock doesn’t mean the end of dairy or beef,” explains Britt Groosman, Environmental Defense Fund’s vice president for climate-smart agriculture. “EDF’s goal is to work with farmers to help lower the methane footprint of that glass of milk or hamburger. Because every bit of ground we gain on methane emissions matters.”

There are various ways to reduce methane emissions from manure. Anaerobic digesters, like those used by the Crave family, is one way. Another is to cover the large ponds — called lagoons — used to store and process manure from cows and pigs. The coverings retain methane that would otherwise be released as the manure decomposes underwater.

To diminish the belching problem, farmers are turning to feed additives that interrupt the microbial processes in a cow’s gut that produce methane. One of the most well-studied feed additives, 3-NOP, marketed as Bovaer, has been shown to reduce methane from belching bovines by about 30%. It was recently approved for use in the EU, Chile and Brazil and is currently being evaluated for U.S. approval. Another promising additive, still in development, is a red seaweed (Asparagopsis spp.) that may cut methane from belching as much as 70%.

A cow who looks pretty surprised
It's a question of gas (Getty)

“These feed additives could be game-changers,” explains Ben Thomas, EDF’s senior policy director for climate-smart agriculture. “For years, people just shook their heads and asked, ‘how do you want us to keep cows from burping?’ But now, there’s something that could really make a dent in these emissions.”

Because these additives must be administered daily, however, they are only viable for dairy cows, which live in a barn, not for beef cattle left to graze in grasslands. These cattle may require the development of a one-time vaccine, slow-release treatment or selective breeding. Still, major progress can be made right now, says Groosman. “We estimate that in the US we can get to about 60% of the targeted reductions in agricultural methane we need with technology that’s already out there,” she says.

Of course, in addition to being a major source of methane pollution, livestock can also cause localized impacts on water quality, air pollution and odor, that often disproportionately affect low-wealth communities and communities of color because of the location of livestock operations. Any strategy to address agricultural methane must not exacerbate these issues.

Don’t be cowed by the cost

Solutions, though, aren’t enough. Someone has to pay for them, and feed additives and manure processing systems can be expensive.

“We can’t ask farmers, who already operate on razor thin margins, to foot the bill for methane reductions if the benefits are exclusively environmental,” says Thomas.

Earlier this year, EDF helped secure a major victory when the U.S. Department of Agriculture announced a first-of-its-kind $1 billion investment in pilot projects that promote farming, ranching and forestry practices that create marketable products or practices that reduce or capture climate-warming gasses. Qualifying projects could include initiatives that cut or capture methane emissions on dairy farms or ranches, and programs that encourage farming practices that soak up more carbon from the atmosphere and store it in the soil.

This investment is thanks in large part to the work done by the Food and Agriculture Climate Alliance, an initiative spearheaded by EDF two years ago to bring environmental and agricultural groups together to push for climate solutions that benefit everyone.

“The fact that ag and environmental groups were willing to team up in the first place and then actually found common ground speaks volumes about both the urgency of addressing climate change and just how much the political calculus has changed,” explains Thomas.

EDF is also working with leading consumer companies to put pressure on their suppliers to reduce methane emissions.

Karl Crave Picture
Wisconsin dairy farmer, Karl Crave.

“We’re making the case to companies that they can’t meet their climate goals without addressing methane from agriculture in their supply chains,” says Katie Anderson, supply chain director at EDF+Business. “And we are helping leading companies to engage their suppliers in high-impact opportunities to reduce methane.”

At Crave, they’re already having some fun letting consumers know about their sustainability practices: A cow swishes her green tail on the label of every one of their cheeses.

Tackling methane across America’s vast dairy and beef operations is a massive undertaking, but a crucial one.

“We need heroes,” says Thomas. “But I can’t think of anyone better suited for the challenge than the hardest working and most resourceful people out there — farmers.”

Hope for a warming planet

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