The race to the methane-free cash cow

Methane is a greenhouse gas many times more potent than carbon dioxide, and livestock accounts for about 14.5% of climate-warming emissions worldwide, according to the United Nations' Intergovernmental Panel on Climate Change. For the past decade, researchers have been investigating the causes and remedies of methane produced by cattle. Between 2016 and 2018 the topic heated to a boil with the discovery that adding seaweed to cattle feed reduced methane burps, especially the red macroalga, Asparagopsis taxiformis.

The race is on!

Scientists all over the world are now intensively working on how to maximize the economic and environmental effectiveness. Researchers are pointing to the bromoform produced by Asparaopsis as the key compound that blocks the production of methane in cows, sheep, goats and other ruminant animals. By changing growing conditions, such as nitrogen and phosphorous, the bromoform concentration can be more than doubled.

Experts are currently debating in which stage to grow the seaweed. The practical considerations include not only the cost of cultivation but its carbon footprint. If growing the seaweed and shipping it to farms generates considerable amounts of greenhouse gas, the process could cancel out the benefits of reducing methane.

Growing Asparagopsis would likely require doing so in tanks of sterilized seawater to prevent contamination of the clingy plant material. That means using some form of energy to pump in air and nitrogen. The problem is it's going to be expensive. The ultimate goal is the most scalable and lowest cost method of production, and to achieve this some point to offshore farming rather than in tanks on land.

There is still some uncertainty with respect to the cattle as well. Will seaweeds reduce methane indefinitely, are there any negative effects to the animals, and will the cows voluntarily eat seaweed infused feed? To address these questions, Ermias Kebreab, an animal science professor at UC Davis, is currently conducting a 6 month feeding trial with cattle.

Many of the outstanding questions will be answered soon enough. Whether motivated by profits or global warming, the race is on to patent recipes for growing, scaling, and processing seaweed for animal feed.