Can Seaweed Save Us?

As countries continue to innovate ways to battle climate change, there is a new, related “slimy arms race” afoot. (Credit to The New York Times for the “slimy arms race” phrasing.) It seems that seaweed, in all its slippery glory, is a multifaceted, under-tapped, and potentially powerful weapon that can be used a number of ways in the ongoing fight to slow or stop global warming.

The World Wildlife Fund calls seaweed a “wonder crop.” It is used as a vitamin-rich food, in medicines (many kinds of seaweed have anti-microbial and anti-inflammatory agents), and in beauty products. It has been used as a kind of biodegradable (albeit expensive) replacement for plastic. As a binding agent, seaweed has been used in the production of toothpaste and fruit jellies. Fast-growing and abundant, swaths of it absorb CO2 — it’s an important carbon sink.

“To offset emissions, cultivated seaweed could be used to replace more greenhouse gas-intensive products like animal-based foods, or in bioenergy systems,” writes Korey Silverman-Roati, a climate law fellow at the Columbia Climate School. “Seaweed could also be sunk in the deep sea for the purposes of carbon sequestration.” Carbon sequestration means capturing and storing carbon, thereby preventing its release into the atmosphere.

When it comes to the above-mentioned “arms race,” there are scientists who believe that a particular kind of red seaweed, asparagopsis, which is found in the waters around Australia, will ease the methane burden produced by more than 1 billion cattle globally. Livestock emissions are responsible for about 40 percent of the methane released into the atmosphere — whether it comes from the animals’ decomposing manure, or from what are known as “cow burps.”

Ermias Kebreab, a professor at UC Davis, has studied how seaweed may be used to cut livestock’s polluting methane emissions. His research has found that as little as 3 ounces of seaweed added to feed each day reduced the animals’ methane emissions by 82 percent.

Having this amount of impact, Kebreab told NPR, “it completely blew my mind and I didn't even believe when I saw the results at first.”

A simple supplement of seaweed might just be part of the answer to climate change, but people, particularly Australians, appear poised to make money off it.

“The race is on, I suppose, to get the world’s first commercial supply,” Steve Meller, an Australian-American businessman in Australia, told The New York Times. “The demand is off-the-roof scale.”

Planted seaweed farms have grown by nearly 75 percent in the past decade, the Times reported. There are now such farms in places like Maine, Australia, and the North Sea. But there is one glaring problem with crowning seaweed the new savior of the planet: Warming ocean waters are killing off naturally growing seaweed along with corals and other species of plants and animals.

This die-off affects not only the oceans’ capacity to capture carbon, but it also threatens the livelihoods of those who dive and harvest the sea floor for a living, such as South Korea’s haenyeo, or freediving “sea women.” There are records of women diving for a living as far back as 57 BCE.

Artificial seaweed farms may help with the cattle-methane problem, but with the dwindling of ocean plants and algae because of climate change — and a shift in who can make their livelihood off them — it seems we're still stuck in a game of one step forward, two steps back.