When more than 1.7 billion cows and buffalo currently on the planet burp, the resulting methane, a potent greenhouse gas contributing to climate change, is a big problem.

Overall, livestock production accounts for roughly 15% of greenhouse gas emissions, with the bulk of that coming from cows and their burps. But in response to that fact, a surprising fix — mixing powdered red algae daily into traditional cow feed — has been discovered, and companies across the globe are rushing to cash in on it. Adding just a single cup of red algae into the feed each day resulted in cows that belched up to 90% less methane.

“The potential of this solution is extremely high,” Fredrik Åkerman, CEO of the Swedish biotech firm Volta Greentech, told Yahoo News. When he was 22, he co-founded Volta Greentech, raising over $5 million of investment for the startup to research red algae and its effects on the digestion of cattle. Now his company is growing the seaweed in ponds and tanks at a land-based facility in Sweden, with plans to become one of the world’s biggest algae farms.

Cow burps have also caught the attention of Microsoft founder Bill Gates. On Monday, Rumin8, an environmental tech company making feed supplements from red algae in Perth, Australia, announced that Gates’s company, Breakthrough Energy, had heavily invested in their $12 million program to run commercial trials of the algae-based supplement in Australia, New Zealand, Brazil and the U.S. Last week, dairy manufacturer Danone, which is headquartered in France and works with 58,000 farmers in 20 countries, announced it aimed to slash methane emissions from its dairy cows by 30% by 2030. Danone, too, is underwriting a red algae startup, this one based in Hawaii.

While news outlets like Fox News have often poked fun at climate change activists and governments like New Zealand’s for their focus on cutting cow emissions, methane is a serious atmospheric problem. It accounts for around 16% of greenhouse gas emissions, but its heat-attracting effects are more intense than carbon dioxide in the short term, trapping 80 times more heat than CO2 in its first 20 years in the atmosphere.

“Over a shorter period, methane is much stronger” when looked at using the global warming potential, said Theun Vellinga, senior researcher at Wageningen Livestock Research, “and it goes up to 80 or 90 times as strong as carbon dioxide. If you average it over the whole period of 100 years, it is still 27 or 28 times stronger. So that’s quite strong.”

Methane levels have been accelerating rapidly in recent years — partly due to increased shale extraction as well as increased thawing of the Arctic permafrost and partly due to the rising number of cows and bulls, according to Vellinga.

Red algae, particularly the seaweed known as Asparagopsis, has been of scientific interest since around 2010, when a Canadian farmer on Prince Edward Island noticed that his cattle near the sea were eating seaweed and seemed healthier than his cattle that grazed elsewhere. He conveyed his observation to a scientist, Rob Kinley, who was working on his PhD at the Dalhousie Faculty of Agriculture in Halifax, Nova Scotia. Studying the cows, Kinley realized that the seaweed-eating cattle emitted far less methane. He later joined the Commonwealth Scientific and Industrial Research Organization (CSIRO), an Australian government scientific research agency, which began publishing groundbreaking papers about red algae — which Åkerman read when he was in high school, after hearing about them on Reddit.

Initially studying electrical engineering in college, Åkerman changed course after contacting CSIRO, instead deciding to harvest red algae in Sweden and start a company focused on reducing methane emissions from cows. Now, Volta Greentech, which collaborates with CSIRO and spinoff Australian company Futurefeed, is figuring out how to mass-produce red algae within cost constraints.

Production is “still small scale,” he said, adding, “There’s no way of implementing this if it costs too much.”

The algae works, he explained, by reducing the number of a certain microorganism that breaks down food in the largest compartment of a cow’s complex stomach, the rumen. Sometimes likened to a food processor, the rumen’s microorganisms break down and ferment food, forming methane, which is released when a cow belches.

But not everyone is wowed by the potential of red algae in fighting methane. “Some people are quite enthusiastic, but honestly, I don’t understand it, because it’s a really hazardous material,” said Vellinga, pointing to bromoform, the active ingredient that lowers methane production in cows.

“In high concentrations, the bromoform is toxic,” said Åkerman. “But we and all the different research groups have made sure that the dose that we are actually feeding to the animals are far, far below the regulated limits. And a lot of studies have been done on the toxicity of bromoform to make sure that it is completely safe.”

On Dutch dairy farms, where red algae supplements have not yet been approved for use, another synthetic methane inhibitor, Bovaer, is more widely in use, said Vellinga. On average, Bovaer “reduces enteric methane emissions [cow burping] by 30% from dairy cows and 45% from beef cattle.”

Agribusiness megalith Cargill recently teamed up with U.K. company Zelp to trial “burp-catching masks” — an innovation that oxidizes the methane, reducing it by over 50% — that received $59,000 from Britain’s Prince Charles for the Terra Carter Design Lab award last year. In Spain, agricultural research is showing that certain cows release less methane than others, and projects are underway to interbreed cows that are by nature less prone to spew the gas.

But each method faces its own challenges. In order to maintain its effectiveness, Bovaer must be fed to cows several times a day, making it less optimal for cattle that graze in fields. Some people, including Vellinga, consider the burp-catching masks to be inhumane to cattle, and farmers aren’t permitted to use them in the Netherlands. Selectively breeding cows that emit less methane, meanwhile, will take many years to make a significant difference, given the size of existing herds.

Another way to reduce methane emissions from cows is to reduce their overall numbers. The Dutch government has already embarked on a plan to thin the number of cattle by 30% over the next seven years. Part of its controversial $27 billion program consists of buying thousands of cattle farms near protected nature reserves in the hopes of reducing nitrogen compounds and ammonia emitted by cows and their urine.

“The government doesn’t believe in the innovations [in reducing ammonia and nitrogen compounds] anymore,” said Vellinga. “So it means that then the only way to reduce emissions is by reducing the volumes of cows.” And while the decision to reduce the Netherlands’ cow stock was made in an effort to curb ammonia and nitrogen compound emissions, it will slash methane emissions as well, he noted.

Eating less meat and dairy products is another means to reduce emissions, simply by reducing demand. While vegans and vegetarians are still a small minority in Europe, more people are becoming so-called flexitarians — eating meat, but less of it.

“A couple of years ago, the big issue was, should we eat beef or become vegetarian,” Ola Thomsson, the purchasing manager at Protos, a Swedish food manufacturer, told Yahoo News. “Now the vegan and vegetarian trend has sort of descended a bit. And now we’re talking more about, perhaps we should eat more vegetables and vegetarian meals, but whatever meat we’re eating should be the right type of meat.”

Protos, which brings meat to market, and Volta Greentech teamed up last summer in a pilot project to introduce the world’s first low-methane meat to Swedish stores. It quickly sold out, and more commercial pilot projects are planned.

According to Innova Market Insights, the flexitarian trend is growing, with “30% [of the population] in Germany and 23% in France” espousing flexitarianism. Even in the U.S., the trend might be growing. A 2021 survey by One Poll commissioned by Sprouts Farmers Market indicated that 47% of Americans who were surveyed self-identified as flexitarians.

Whether through food supplements, masks or changing behavior, climate change watchers are urging change and methane slashing quickly. “Reducing human-caused methane emissions is one of the fastest, most cost-effective strategies to reduce the rate of warming and contribute to global efforts to limit temperature rise to 1.5°C,” stated a 2021 report released by the Climate and Clean Air Coalition and the U.N. Environment Program.

Giving red algae to cows appears at first glance to offer one possible mechanism to curb methane emissions. Whether it can be produced fast enough to be fed to the world’s many millions of cows, however, remains to be seen.

“When considering new ways to reduce methane, it’s always complex: Does it reduce methane for a long time or just temporarily, what are the consequences for animal health, milk quality, food safety, is it affordable, is it easily applied?” Vellinga said. When it comes to red algae and the other methane remedies coming onto the market, he remains cautious and not yet fully convinced.