They're funny in theory (farts always are) but they're actually pretty destructive to the environment. Cow farts are methane and methane isn't great when pumped into the air in massive amounts, which is only increasing as factory farming grows to meet the demands of consumers. Livestock accounts for 30 percent of all global methane emissions, pumping out 3 gigatons of the gas every year in their bodily waste. Methane is an especially potent greenhouse gas: During its 12-year lifespan after being released, it traps 84 times as much heat as carbon dioxide, and its effect on global warming over a century is 34 times that of CO2.
The United States have few regulations around cattle methane. The Environmental Protection Agency’s AgStar program trains farmers to turn animal waste into biofuel using anaerobic digesters, but it is optional — 8,000 farms could implement it, but only about 250 have done so.
Ermias Kebreab, an animal science professor at the University of California–Davis, has spent 15 years studying alternative ways to reduce livestock effusions. During his research, he heard that scientists at Australia’s James Cook University had discovered a drastic decrease in methane production when the scientists mixed bacteria from cows’ digestive systems with red seaweed. The results were promising: reformulating a cow’s diet to contain 2 percent seaweed could reduce its methane emissions by 99 percent.
Kebreab's team mixed varying levels of a type of red seaweed called Asparagopsis armata into the feed of 12 dairy cows over a two-month period. The results were shocking: When the cattle’s chow consisted of just 1 percent seaweed, their methane emissions went down 60 percent. “In all the years that I’ve worked in this area, I’ve never seen anything that reduced it that much,” Kebreab says. While these are preliminary results, they are exciting.
Seaweed doesn’t require precious freshwater, fertilizer, or land to grow. It can reverse ocean acidification by absorbing carbon dioxide. One study suggests we could remove the equivalent of 42 percent of all current global CO2 emissions by covering 4 percent of the world’s oceans in seaweed farms.
These results come in a time of crisis. California alone has come 180 million dairy cows. While better funded and long term experiments have continued showing promise, Kebreab’s biggest hurdle has been finding enough seaweed; the variety that’s useful for cows isn’t domestically available.
Massachusetts-based Australis Aquaculture hopes to cultivate red Asparagopsis in the waters off the coast of Vietnam. CEO Josh Goldman is excited about the prospect of feeding seaweed to cows: “You don’t have to rebuild 10,000 power plants in the world. You basically create a modest feed additive that has a big leverage effect.”