Seaweed Could Make Cows Burp Less Methane and Cut Their Carbon Hoofprint

A diet supplemented with red algae could lessen the huge amounts of greenhouse gases emitted by cows and sheep, if we can just figure out how to grow enough. From a report: In a wooden barn on the edge of campus at the University of California, Davis, cattle line up at their assigned feed slots to snatch mouthfuls of alfalfa hay. This past spring, several of these Holstein dairy cows participated in a study to test a promising path to reducing methane emissions from livestock, a huge source of the greenhouse gases driving climate change. By adding a small amount of seaweed to the animals' feed, researchers found, they could cut the cows' methane production by nearly 60%. Each year, livestock production pumps out greenhouse gases with the equivalent warming effect of more than 7 gigatons of carbon dioxide, roughly the same global impact as the transportation industry. Nearly 40% of that is produced during digestion: cattle, goats, and sheep belch and pass methane, a highly potent, albeit relatively short-lived, greenhouse gas.

If the reductions achieved in the UC Davis study could be applied across the worldwide livestock industry, it would eliminate nearly 2 gigatons of those emissions annually -- about a quarter of United States' total climate pollution each year. Ermias Kebreab, an animal science professor at UC Davis who leads the work, is preparing to undertake a more ambitious study in the months ahead, evaluating whether smaller amounts of a more potent form of seaweed can cut methane emissions even further. Meanwhile, some businesses have begun to explore what could be the harder challenge: Growing it on a massive scale.

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