A cure for cow burps?

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?