Cow Burps & Climate Change

A special ingredient could break the connection.

Think of pollution and what comes to mind—smokestacks? Gridlocked traffic on the highway? Probably not ol’ Bessie in her pasture. Yet livestock is a major producer of methane, a greenhouse gas 30 times more potent than carbon dioxide. In California alone, more than half of all methane emissions come from the state’s 1.8 million dairy cows as they burp, exhale, fart and produce manure.

Yes, cattle are a gassy bunch, but they don’t have to be. These troubles of the turf may be relieved by a product of the surf.

Jennifer Smith, a marine ecologist and seaweed expert at Scripps Institution of Oceanography at UC San Diego, was intrigued by a recent UC Davis study in which small amounts of dried seaweed were added to cattle feed. Preliminary results showed a remarkably promising 50% reduction in methane emissions, but it is still unknown whether growing enough seaweed to meet industry demand is possible.

Smith set herself to find out. Since early 2019, she’s been growing the red algae seaweed Asparagopsis taxiformis in her lab, exploring the potential for cultivation on a larger scale. Her shelves look otherworldly, with flasks of seaweed sporophytes looking like tiny pink pom-poms swirling with excitement.

“The opportunity to potentially manage methane emissions from cow burps had never really been on the table,” said Smith. “But this unusual collaboration—a marine biologist working with the livestock industry and livestock scientists—might have an influence on greenhouse gas emissions.” She adds, “It’s a crazy marriage of three totally disparate fields of science and I’m really excited to be part of that.”

Smith is working to find the “sweet spot” where the seaweed grows at its highest rate while also increasing its concentration of bromoform—the compound responsible for reducing methane-making enzymes in a cow’s gut.

There’s much work to be done to see if large-scale cultivation is possible, but Smith is driven by the possibility of contributing to research that could have swift impacts on the environment. Methane has a relatively short life span in the atmosphere—about 10 years— meaning changes made today could yield big results in the near future.

Asparagopsis is a complicated seaweed and little is known about its biology, so that poses a lot of opportunity from a scientific perspective,” says Smith. “It’s not something that we can just start scaling tomorrow. We have a lot of work to do to learn more about its biology, physiology and ecology before we can develop a model for scaling cultivation.”