‘We Need a Tesla for the Cow’: The Wild, Dubious Plan to Feed Cows Seaweed

Imagine a perfect burger: juicy, grilled to perfection … and, somehow devoid of the guilt of methane emissions wrecking our planet. Scientists and food companies in recent years have said it’s possible to engineer more climate-friendly beef, and a growing number of headlines that claim that feeding cows seaweed could be a silver bullet to leaching their burps of methane.

A little bit of algae, the research shows, could nearly eliminate methane emissions from cows. Thanks to an avalanche of stunning research findings, good press, and excitement (and funding) from the food industry, the seaweed-to-burger pipeline is growing quickly. Yet the solution has yet to lift off at anywhere near the scale needed to rein in a huge source of planet-warming pollution—and it may not be a one-size-fits-all solution.


The cow-methane connection has become a focal point of research and informed the culture wars. Just this week, conservatives have started fanning the flames anew with a lie that President Joe Biden’s climate plan will require Americans to reduce their meat consumption by 90% (it won’t). Meanwhile, food site Epicurious announced on Monday that it had quietly stopped publishing new recipes featuring beef last year in an attempt to help readers choose more climate-friendly meals.

Cows produce methane because of the microbes in their stomachs that break down food. Cattle is the largest source of global greenhouse gas emissions tied to agriculture. Because meat consumption is growing, that means it poses a greater problem to the planet. Americans consume roughly 55 pounds (25 kilograms) of beef annually. Though that’s dropped from a high of around 90 pounds (41 kilograms), consumption is rising elsewhere, particularly China.

As proposals to address climate change like the Green New Deal have arisen, reactionaries have seized on the humble cheeseburger as a way to delay action. (For the record, the Green New Deal would not ban burgers.) Still, reducing cattle’s methane footprint as part of an effort to fix agriculture is a necessity given the need to protect the climate.

Seaweed isn’t the only thing being fed to cows to see if it helps with their burps, said Breanna Roque, a graduate student researcher at the University of California, Davis working with a team on the methane-algae connection. “There’s a lot of work being done [in agricultural research], like, what can we feed cattle?” Roque said, explaining that cows’ powerful stomachs can digest stuff that we can’t. That could help with both food waste and figuring out how to tinker with cows’ methane-laden burps. “We could feed them products that are indigestible and turn them into a high-quality protein for human consumption—that’s a win-win.”

Cows have responded well to eating agricultural scraps like nut shells and cotton seeds, while corn and bean fodder have also been found to lower emissions compared to grass. But seaweed has been the real star of the story, reducing methane emissions in beef cows in the latest UC Davis study by up to a jaw-dropping 80%.

“We’re feeding a small amount of seaweed with the diet, and it’s reducing methane emissions greater than any additive we’ve seen before,” Roque said.

Not all seaweeds are created equal. The type Roque and her fellow researchers have found to be the best at reducing methane is red seaweed, known as Asparagopsis taxiformis. The Asparagopsis seaweed, Roque said, essentially works to directly target the microbial populations that produce methane in the cow’s rumen. Roque and her team measure the impacts of Asparagopsis by offering cows alfalfa pellets (“we call them ‘cow cookies,’” she said) sprinkled with seaweed at a special feeding station, which then measures the cow’s burps as they munch. Only a small amount of seaweed is given to each cow, meaning, Roque said, “feeding a little bit of seaweed every day can drastically reduce the amount of methane.” To make matters even better, Roque said that on taste panels UC Davis has conducted, no one could tell the difference between beef and milk from seaweed-fed cows.

The next steps to this seemingly perfect solution, Roque said, would be clinical trials with the FDA to approve Asparagopsis-laced feed for the commercial market. And then, of course, there is the issue of creating enough seaweed to feed millions of cows across the world.

“It’s just going to take a while to scale up production,” she said.

That’s where Joan Salwen hopes to come in. “We need Tesla for the cow, and where is that?” Salwen said. “There’s no question that the right amount of fresh and vibrant seaweed will reduce methane emissions by 80% to 90%. Can we feed this to every single cow in the whole world?”

Salwen is the founder of Blue Ocean Barns, a startup that she has referred to as the “commercial engine” for the algae-to-cow pipeline. (Roque’s supervisor at UC Davis serves as a scientific advisor for the company.) Blue Ocean Barns is one of a handful of companies and groups around the world working to figure out how to farm and harvest Asparagopsis seaweed for the cattle market.

Salwen explained that all the work with seaweed thus far has been with wild seaweed harvested by divers, which, obviously, isn’t practical to scale up to the level needed for industrial agriculture. The other two options, Salwen said, would be creating ocean-based farms or the method Blue Ocean Barns is trying: land-based vertical tanks, filled with ocean water pumped from the deep sea, which she said will allow to the Asparagopsis to grow “at commercial, industrial, kickass scale.”

Currently, Blue Ocean Barns has been experimenting with a seed bank looking for samples that have the highest growth rates; the company hopes to open their first two-acre farm in Hawaii this summer. Salwen stressed that the effectiveness of seaweed as a solution has driven the breakneck progress her company and others have made.

“In four years we’ve gone from analyzing this for the first time in test tubes to having farms that are beginning to grow this seaweed, so honestly I think we deserve some credit,” she said. “We’re moving the ball pretty quickly, especially when it started at academic speed.”

And both big and small food companies have thrown their weight behind Salwen’s seaweed. Straus Family Creamery, the nation’s first certified organic milk producer that sells its products in glass bottles, touts its connection to seaweed trials in its sustainability report. Meanwhile, beef and dairy giants Mars Wrigley and Land O’Lakes have also praised Blue Ocean Barns’s work. Big industrial food companies, Salwen said, “are really excited about the potential of being able to meet science-based targets that they have publicly announced that without this technology, they’d have no chance of meeting.”


That excitement from Big Meat is what worries Jan Dutkiewicz, a political science researcher and policy fellow at Harvard, and Matt Hayek, an assistant environmental studies professor at New York University.

“People are starting to realize that animal agriculture, particularly beef, has a really outsized environmental impact,” Dutkiewicz said. “People are drawn to solutions to their everyday problems that don’t require much change to personal practice. [Meat companies] are capitalist entities who are interested in maximizing profit and maximizing goodwill. Of course, the primary interest on the part of the meat industry is to be able to sell goodwill and get rid of emotional or ethical concern consumers might have around things like animal welfare and the environmental impact of their purchases.”

In response to the growing number of headlines touting algae as a catchall solution for Big Beef’s ills, Dutkiewicz and Hayek authored an op-ed in Wired last month addressing what they see as the primary problems with designating seaweed as a cattle savior. Both Dutkiewicz and Hayek stressed that their issue is not with the scientific work itself, but rather with how it is being presented to the public.

One big issue is how much those methane emissions achieved in the UC Davis setup would actually translate into the real world. Hayek said that most methane emissions from cattle come from when they graze on pasture and eat grass—but the seaweed trials have only fed cattle in a scenario that mimics a feedlot, where beef cattle spend a small, final portion of their lives. Hayek estimated that if researchers don’t find a way to feed cattle seaweed as they graze on pasture—a much more difficult proposition than mixing it in with grain or alfalfa feed on a feedlot—feeding cows seaweed would only reduce methane emissions by 8.8% over a cow’s life. Not exactly a silver bullet.

“We do know that mandating veganism is less likely to be successful (witness New York’s failed ban on soda as an example) than meeting the livestock industry where it is and reducing emissions substantially from its largest source, enteric fermentation,” Salwen told me over text message when I sent her the Wired essay, while noting she and others on the seaweed front “are not trying to offer redemption for burger lovers.”

She said that dairy cows, which burp more methane than beef cows, were “a good place to start with seaweed supplementation” since daily milking could provide a chance to give the cows their daily algae snacks while working out the kinks of getting seaweed out to pastures. By her estimation, seaweed could scale to reach “millions” of cows by mid-decade and “a hundred million by the end of the decade,” which would indeed be a Tesla-like feat.

“It’s unfortunate that some university professors would take the time to, with limited understanding, resort to name-calling and seek to slow the progress of a hugely promising, if not perfect, technology down,” she said.

The animal agriculture industry has a whole host of other climate-related problems that aren’t just caused by cow burps. The beef industry has been a huge driver of deforestation in the Amazon as companies raze the world’s largest carbon sink to make room for cattle pasture. Emissions from agriculture come from all parts of the production cycle, from fertilizer use to manure lagoons to transportation. That includes carbon dioxide, the most common greenhouse gas tied to human activities, and nitrous oxide, another potent greenhouse gas. Meanwhile, animal ethics and the abhorrent treatment of slaughterhouse workers continue to plague the industry.

Last summer, Burger King rolled out a burger it called “methane-reduced,” claiming that it had fed cows lemongrass that was able to reduce their methane emissions by 33%. (The commercial for the burger featured none other than Mason Ramsey, the yodeling Walmart kid.) The lemongrass burger and accompanying unpublished research from the burger giant was widely panned, but it points to how meat companies could hyper-focus on silver bullets in an attempt to distract customers from the other problems behind the curtain.

“Let’s say the algae thing works as promised,” Dutkiewicz said. “You can do mass-scale algae monocrops, you can make this economically viable, you can somehow get this to hundreds of millions of cows around the world, all which are huge question marks, let’s say all of that works. You’re still talking reducing total methane emissions from cows by maybe eight, 10%. It’s not affecting any of [the industry’s] other vast harms. What you’re doing is chipping away minorly at one of a vast number of parts.”

For Hayek, raising concerns about the algae idea is less about bashing new technologies, and more about refocusing on the solutions we do have at hand. That includes not banning meat altogether, but eating it on a scale that doesn’t end up destroying the climate.

“There’s the time component of this,” he said. “A couple of folks have really pressed me, you seem to be giving up on [algae] before we’ve given this an actual shot. That’s not the calculus. I think every bit of research needs to be put into mitigating greenhouse gases from every sector of the economy. … My concern is that we get distracted as a society from knowing that eating far less meat is a major food system mitigation tool we have today that is technically sound and we know that works.”