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To fight climate change, California approves seaweed that cuts methane emissions in cow burps

San Francisco Chronicle logo San Francisco Chronicle 5/6/2022 By Tara Duggan

California dairy farms will soon be able to feed their cows seaweed to fight climate change after the state Department of Food and Agriculture approved the use of a seaweed feed shown to reduce methane emissions from cow burps, the first in the U.S. to do so.

On Friday, Blue Ocean Barns, which produces the red seaweed at a farm on the Big Island of Hawaii, announced that the supplement had been approved for use on both conventional and organic dairy farms. Called Brominata, the red seaweed variety has been shown to cut methane emissions in dairy cows by 52% over 50 days but so far has been used only in trials.

“California is being really bold and putting their money where their mouth is in their desire to have a sustainable dairy industry,” said Joan Salwen, CEO of Blue Ocean Barns. “They were very much first to grant a license and approve labels and get us into the market.”

California also produces more cow milk than any other state, and its dairy cows are the source of 45% of California’s methane emissions, a potent greenhouse gas, according to UC Davis. The emissions are so plentiful that satellites were able to detect them being released from a large California feedlot near Bakersfield last month from space, according to Reuters.

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The seaweed supplement will likely be available for commercial use this summer for conventional farms and in 2023 for organic farms. The variety that works to reduce emissions is still available only on a limited scale worldwide, and Blue Ocean Barns began ramping up production in 2020 to meet demand. It is adding more acres to its farm this year and next to be able to feed 1 million cows by 2025, Salwen said.

“The material is in short supply in 2022,” she said. “We’re making strides and looking toward really large scale production.”

Red seaweed was also shown to reduce the methane emissions of beef cattle by 82% in a study published last year by UC Davis. The seaweed supplement, which makes up only a tiny portion of cattle’s diet, is not known to change the flavor of beef or milk.

Straus Family Creamery in Petaluma, which hosted the trial last year for dairy cows on one of its supplying Marin farms, plans to be one of the first companies to use the supplement. That will enable one of its farms to become carbon-neutral by the end of 2023 and the rest by 2030, said CEO Albert Straus.

“It’s a huge step forward that meets not only the goals of California to reduce their methane emissions,” he said, “but it’s showing the way for California and the world that we have solutions that can be replicated.”

Tara Duggan is a San Francisco Chronicle staff writer. Email: Twitter: @taraduggan


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