Methane biodigester on a dairy farm. Photo courtesy of iStock

Reducing methane emissions took center stage at the United Nations Climate Change Conference in Glasgow ending Friday. More than 100 countries pledged to reduce their methane emissions by 30% over the next decade. Methane is a significantly more potent yet shorter-lived greenhouse gas, making it a target to prevent near-term warming as societies hurtle towards the 1.5 degrees of warming deemed disastrous for life on Earth.

In tandem with this global commitment, the Biden administration released its plan to bring down U.S. methane emissions. While this plan would set new limits on methane emissions coming off oil and gas plants, it does not regulate the single largest source of U.S. methane emissions: animal agriculture.

Instead, the Biden administration will rely on “incentive-based and voluntary” efforts, predominantly encouraging livestock farms to install methane capture devices and digesters that collect and transform manure into burnable biogas. Proponents say methane digesters can turn farms’ air pollution into a new energy source and revenue stream.

But critics argue digesters are an expensive tweak to accommodate and expand fundamentally dirty enterprises. Digesters target methane emissions coming off liquified manure lagoons, a byproduct of large, confined animal farms (CAFOs). Installing digesters encourages CAFOs to raise more animals to produce more manure to feed digesters, generate energy, and make returns on their investment. But these incentives expand the underlying hazards in question and further consolidate livestock production. Instead, environmental advocates want governments to regulate CAFO air pollution, address policies that encourage overproduction, and invest in more sustainable livestock systems that release less methane.

“You could have a bigger impact if you start to appropriately regulate these operations,” says Ben Lilliston, director of rural strategies and climate change at the Institute for Agriculture and Trade Policy. “I think that would have just as quick an impact as methane digesters, and it would serve to put us on a path towards a transition in our systems for raising animals.”

The U.S. is the world’s second-largest meat and dairy producer, and Americans eat more meat per person than almost every country in the world. Nearly 70% of agriculture-related methane emissions come from ruminants, such as cows, living their lives and belching gas. Another 24% comes from animal manure that decomposes “anaerobically” or without oxygen, primarily liquified manure in CAFO lagoons (by contrast, cow patties on pasture release much less methane as they break down).

Liquified manure lagoons and their emissions have proliferated since the late 1980s as pork and dairy production, in particular, consolidated onto CAFOs. These large hog and dairy farms account for the vast majority of manure-related methane emissions and 13% of all U.S. methane emissions. Large CAFOs and their concentrated waste also introduce air and water quality concerns, correlating with higher levels of asthma and lower life expectancies for neighboring communities. They also drive smaller farms out of business — between 1987 and 2017, more than 70% of hog farms and dairy farms disappeared even as pork and milk production increased.

U.S. Agriculture Secretary and former dairy lobbyist Tom Vilsack told the Guardian, “I do not think we have to reduce the amount of meat or livestock produced in the US” in order to decrease methane emissions. Instead, Vilsack and the Biden administration are promoting technical solutions to reduce livestock methane emissions, including methane digesters. Farmers can tent their manure lagoons to capture methane. Farmers then send this gas and their manure through a large device, the digester, where it decomposes without oxygen and generates more methane that can be refined into burnable gas. Digesters range from smaller closed-loop devices that produce energy on the farm to large regional refineries taking in manure and gas from surrounding farms.

Digesters are very expensive, running from $1.2 million to $5 million for on-farm systems and $15 million to as much as $100 million for larger refineries. Substantial state and federal programs exist to help cover these costs. Farmers can also make money selling their waste and methane to energy companies, generating energy on-farm with a personal digester, or applying for sellable offset credits representing their reduced greenhouse gas emissions. The Biden administration’s methane reduction plan would expand government funding for digesters. But some environmental and agriculture policy groups oppose this approach.

Assuming perfect use, digesters can reduce methane emissions coming off manure lagoons. But building them encourages CAFOs to raise more animals and produce more manure. “This infrastructure necessarily incentivizes more waste to go into these facilities; it’s not a method to reduce waste,” says Rebecca Wolf, policy analyst at Food & Water Watch.

For instance, Smithfield has recently contracted with a cluster of 17 large new hog farms in Beaver County, Utah, which will all supply methane to the corporation’s Align Renewable Natural Gas initiative with Dominion Energy. Some digester projects even collect animal waste that doesn’t release much methane, like chicken litter, and use it to generate more methane than would have existed otherwise. “I think the word capture is a bit of a rosy term,” Wolf says. “[Digesters] are not just capturing [methane], they are also generating and refining it.”

New revenue streams from manure give larger farms yet another edge over smaller ones. Reporting in Hoard’s Dairyman estimated that dairy farmers contracting to supply manure to digesters may reap more profits from their manure than milk. “If the manure becomes more valuable, it gives a huge advantage in the marketplace to mega-dairies over any other dairy [and] it also creates incentives for that dairy to keep getting bigger,” says Lilliston. One study found that a ton of manure from a large dairy farm releases over twice as many greenhouse gas emissions as a ton of manure from small dairies.

Expanding CAFOs and manure production exacerbates air and water pollution beyond just methane. Since low-income communities and communities of color are more likely to live near CAFOs, a rural California advocacy group recently petitioned the California Air Resources Board to exclude farm biogas and digesters from qualifying for carbon offset credits or low carbon fuel programs on civil rights grounds.

Instead of subsidizing CAFO cleanup, Wolf and Lilliston want the government to set stricter standards for agricultural pollution. CAFOs face few meaningful air and water quality regulations. Effective pollution standards put the onus on farms and meat corporations to account for harmful production methods. “We’re not responsible for the industry’s waste,” Wolf argues. “[Digesters are] being sold as a solution to a problem that is not ours to solve —the problem is the factory farm model in and of itself.” Food & Water Watch and IATP joined 23 other organizations in petitioning the EPA in April to set limits on methane emissions for large hog and dairy farms.

Lilliston argues that lax environmental regulations, and other direct and indirect subsidies for meat and dairy, make prices artificially low and encourage overproduction. “The only way to really slow down this massive growth in production is to make the industry account for all of its costs, and right now they’re not,” says Lilliston. “Our meat and dairy shouldn’t be as cheap as it is, and when it’s this cheap it spurs a lot of consumption.” Further, Lilliston says most of the growth in U.S. meat and dairy production in recent decades has gone into overproduction for export markets. Before joining the Biden administration, Vilsack promoted export-oriented milk production as president of a trade group representing large dairy processors.

If meat and dairy reflected its societal costs, people might consume less of it, lowering livestock populations and their methane emissions. Wolf and Lilliston also argue that instead of digesters the Biden administration should invest in more sustainable livestock systems, such as rotational grazing, that avoid creating hazardous manure lagoons to begin with.