Unsplash/Tim Wright


Better burps. There’s a new weapon in the war on climate change, one that takes aim at a lesser-known source of greenhouse gasses: cow burps. Cows, as we’ve previously reported, belch out 150 kilograms of methane every year—not a good thing, since there are many millions of them, and since methane is about 30 times more planet-warming than standard C02. But Australian researchers have discovered a new way to reduce the environmental impact of disgruntled bovine guts. According to a new study reported by the Australian Broadcasting Corporation, introducing a little seaweed to cows’ diets can drastically cut the methane content of their burps.

Asparagopsis taxiformis, a type of red seaweed, cut methane emissions by as much as 99%.

Rocky De Nys, a professor of aquaculture at James Cook University, studied 20 different types of seaweed to see which would have strongest effect. To do that, his team simulated a cow’s rumen by mixing little pieces of stomach, various grasses, and seaweed in lab bottles, and watching to see what the combinations would emit. One species in particular blew away the competition: Asparagopsis taxiformis, a type of red seaweed, cut methane emissions by as much as 99%. (Strangely, it’s kind of the color of Pepto Bismol.)

It could be a major breakthrough, considering that the agricultural sector is one of the biggest global contributors of greenhouse gasses, and that 65% of its emissions come from bovine belches. But remember that the whole reason cows burp so much in the first place is because they’re fed an unnatural diet—typically cheap ryegrass, soy, and corn, when they should be grazing on naturally-growing grasses and legumes. Our methane problem is the unintended consequence of commercial feed. What would be the unintended consequence of all that red seaweed, enough to feed the world’s cow herds?

Joe Fassler bio

Joe Fassler

Joe Fassler is The New Food Economy's features editor. His food safety and public health reporting has twice been a finalist for the James Beard Foundation Award in Journalism (2011 and 2018). Contact him on Twitter at @joefassler or by email at [email protected]

Sign up for our Newsletter

Get a weekly dish of features, commentary and insight from the food movement’s front lines.