Feeding Cows Seaweed Reduces Their Methane Emissions, but California Farms Are a Long Way From Scaling Up the Practice

The Straus Family Creamery, an organic dairy producer in Marin County, California, made headlines last fall after receiving approval from regulatory agencies to conduct a trial of a new seaweed-derived feed additive called Brominata. 

Brominata is made of a red seaweed, Asparagopsis taxiformis, and is one of a class of feed additives that, when given to dairy cows, helps to reduce the amount of methane—a powerful greenhouse gas—they release when they burp, called enteric methane. One cow belches out 220 pounds of methane each year, the greenhouse gas equivalent of burning over 900 gallons of gasoline. 

The addition of the seaweed to the cows’ diets on the Straus dairy farm proved effective, showing an average of a 52 percent reduction in enteric methane emissions, with one cow’s emissions reduction as high as 92 percent. 

For Albert Straus, the founder of Straus dairy farms, the first 100 percent certified organic creamery in the country, the trial was an opportunity to show the public that the dairy industry could be part of a climate solution. “My vision and goal is to prove that [dairy farms] are an asset to the community,” said Straus. “It’s about being able to show that livestock have an important role in the future.”

Now, as other studies have shown that seaweed has the potential to reduce the amount of methane in cow burps by a similar amount, the California Air Resources Board believes feed additives could play a role in helping the state reach its ambitious goal of a 40 percent reduction of 2013 greenhouse gas emissions by 2030. 

But as with so many other climate solutions, feed additives take considerable energy to produce, have their own environmental issues and face regulatory delays. And it’s still not clear whether enough of them can be produced to make a significant reduction in methane, a climate super-pollutant which traps about 80 times more heat in the atmosphere over a 20-year period than carbon dioxide.

This March, the California Air Resources Board released a report that named feed additives as an emissions-reduction strategy for the dairy industry, along with methane digesters—facilities that trap methane produced from cow manure and create biogas.

The report stated that the California dairy industry has a long road ahead if the emissions goals are to be met, and projected that the dairy and livestock industry in the state is on track to achieve just over half of the methane emissions reductions needed to meet the 2030 goal. 

According to the CARB report, if no new digesters are built between now and 2030, California farmers will have to use a feed additive that reduces methane by at least 50 percent on at least 75 percent of its ruminant animals—about 4 million of them—in order to meet emissions goals. 

However, feed additives that claim to reduce enteric methane aren’t yet approved for use in the U.S. A synthetic feed additive called 3-NOP has been shown to be effective in reducing enteric methane emissions by about 30 percent, depending on its concentration in an animal’s diet. 3-NOP has been approved for use in the European Union and other countries, but is waiting on FDA approval for use in the United States.

“Nobody knows how long it’s going to take,” said Ermias Kebreab, a University of California,  Davis researcher and chair of the United Nations Food and Agriculture Technical Working Group on Feed Additives. “We are a long way away from that at the moment.”

The Brominata seaweed feed additive that Straus plans to use, though, has been approved as Generally Regarded As Safe by the California Department of Food and Agriculture, making it one of the only options for dairy farmers looking to reduce their enteric methane emissions. The next step for seaweed, said Kebreab, is to apply for FDA approval so that Brominata can officially claim to reduce methane emissions and be made available to farmers across the U.S.

Brominata is grown in a land-based cultivation system in Kailua-Kona, Hawaii, at a company called Blue Ocean Barns. According to Straus, Blue Ocean Barns is working on scaling up production, and will have enough seaweed for his herd of 270 cows by 2023. Joan Salwen, CEO of Blue Ocean Barns, said in a statement that the company expects their capacity to feed cows to “more than double,” before 2025.  

However, land-based seaweed cultivation systems have environmental impacts of their own, according to Michael Martin, a senior researcher at the Swedish Environmental Research Institute. A study published this year by Martin, which focused on an on-land seaweed cultivation company in Sweden, found that seaweed cultivation can demand high energy inputs in order to heat and illuminate seawater to the conditions required to grow Asparagopsis, which is native to the warmer waters of the Mediterranean Sea. 

Seaweed cultivation causes a number of other environmental effects, as well—if wastewater from the cultivation process isn’t filtered correctly, it could introduce too many nutrients into the open ocean, leading to eutrophication, or nutrient enrichment, which can cause ocean acidification and algae blooms. The salt needed to increase salinity to the levels required by Asparagopsis could also pose an environmental impact, since it must be transported via ship and then truck to the cultivation facility. 

The environmental impacts of on-land seaweed farming, said Martin, is highly dependent on the location of the cultivation system as well as the energy grid to which the system is connected. In the Swedish system studied, more energy was needed to heat the north-Atlantic seawater than might be needed at Blue Ocean Barns in Hawaii. However, the electricity powering the Swedish facility in Martin’s study was entirely from wind power. Hawaii, as of October of last year, gets 77 percent of its power from burning fossil fuels. “Our environmental inputs are negligible compared to our CO2 reductions, yet we seek to continually decrease the carbon footprint of our cultivation and distribution,” said Salwen.

Even if seaweed cultivation can technically be scaled up, Martin isn’t sure it will be economically viable on a large scale—it all depends on whether farmers will want to use the additives. Getting dairy farmers to adopt seaweed might be tricky, said Joseph McFadden, an associate professor of dairy cattle biology at Cornell University, because farmers are worried about their bottom lines. 

Kebreab said it could be possible for farmers to trade their carbon offsets received by using seaweed. Reducing enteric methane emissions also makes dairy producers more attractive to clients like Nestle, Starbucks or Walmart, which are interested in pushing their organizations toward net-zero carbon emissions. Another possible incentive, said McFadden, would be to determine if seaweed feed additives can also improve cows’ health and milk production. “Farmers are only going to adopt these technologies if they enhance their profitability,” he said.

However, said McFadden, “there’s a lot of unanswered questions regarding seaweed.”

Martin said he’s worried that the marketing of seaweed and other feed additives as carbon-neutral or climate-friendly will also mislead consumers into thinking that consuming dairy products is environmentally harmless, and might even lead to an increase in dairy product consumption. “If we reduce the emissions [of cows], oftentimes what we see is a rebound effect where people think it’s not bad to drink milk or eat beef,” he said. “And that kind of defeats the whole purpose.”

“To go into this thinking that you’re going to find this magic solution in a couple feed additives that reduce methane 50 percent across the board is a bit naive, I think,” said McFadden. “But we all can be hopeful.”