The UC Davis study will contribute to a global store of knowledge on how to limit the methane produced by “enteric fermentation” — the digestive process in a ruminant’s upper stomach chamber, or rumen, where microbes predigest fiber and starch, releasing gases when they belch and exhale. It’s “one of a handful of options in various stages of development that seem to have the potential to reduce [enteric] methane by 30 percent or more,” says Ryan McCarthy, science advisor to the Air Resources Board.
Kebreab’s experiments with seaweed additives to cattle feed have now surpassed that 30-percent figure, with one type of seaweed slashing enteric methane by more than 50 percent. In the fight to slow climate change, such reductions are no small matter: In the United States alone, domestic livestock — including cattle, sheep, goats, and buffalo — contribute 36 percent of the methane humans cause to be put into the atmosphere, according to the U.S. Environmental Protection Agency.
