Methane-spewing cow burps are killing the planet. Livestock contributes 14.5 per cent of human-caused greenhouse gas emissions, according to the UN’s Food and Agriculture Organisation, and cows make up two-thirds of that figure. Four years ago, Josh Goldman read research from Australia’s national research agency CSIRO and James Cook University in Queensland that suggested a solution: seaweed.
Sprinkle a tiny bit of Asparagopsis taxiformis into a cow’s dinner, making up about 0.2 per cent of their total meal, and they burp 85 per cent less methane – and, early trials show, require less food overall, as all that belching wastes energy. But for this red seaweed to solve cow burps, it needs to be easy to grow: 200 million tonnes of it will be needed if it is to feed the world’s cattle.
To help tackle the challenge, Goldman was directed to seaweed researcher Leonardo Mata, who has been studying the plant for decades and at the time was the only one to cultivate it. Their collaboration has become Greener Grazing, part of Goldman’s wider sustainable farming firm Australis Aquaculture.
There are two main types of seaweed, Goldman says. “One is seaweed that to cultivate you literally take a big plant, cut it up, and then tie or glue the cuttings to a rope and they regrow. But other seaweeds have much more complex life stories, and this falls into that second category.”
To successfully dose the world’s cattle, Greener Grazing is trying to make Asparagopsis taxiformis morph into the simpler type of seaweed. This involves developing a seed bank to study the seaweed’s genetics and unpick what is needed to make it grow on land long enough to induce a process called sporogenesis, which gets the seaweed to release spores. “We collect those, clean them up and stick them to ropes that we can transfer to the ocean,” Goldman says.
Ocean trials are currently running in Vietnam, and the first commercial harvest is planned for 2021, though work remains to refine the process so it can scale cost-effectively. The aim is to supply spore-seeded ropes to farmers, but also to process the harvested seaweed to extract the key compound, known as bromoform.
As the seaweed also absorbs CO2, Goldman hopes that cultivating it could have an added environmental benefit: “The oceans are getting more acidic, and seaweed farming is a way to combat that.”
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