Food systems worldwide are straining. Global warming, demand, and unsustainable land usage are straining terrestrial agriculture. Our overstressed lands have seas of untapped potential.

A Nature study found 650 million hectares of ocean, roughly the size of Australia, ideal for large-scale kelp cultivation. The report believes this growing sector may feed humans, and cattle, make biofuels, halt climate change, and offer habitat for a wide variety of marine creatures. Can seaweed do anything?

It’s yes. The study’s authors note seaweed aquaculture’s effect and scalability limits. “I think they’re just a little harder to see because we are starved for solutions to the climate crisis and biodiversity crisis,” says co-author Scott Spillias, a seaweed farming doctorate candidate at the University of Queensland in Australia.

Farmers and businesses must overcome challenges that include scaling Western farms, growing the seaweed market, and decreasing environmental concerns. However, this research provides a solid estimate of the industry’s potential size.

Commercial seaweed cultivation is still new outside East Asia.

Most Western seaweed farms are new, yet Indigenous Americans have cultivated seaweed for decades. Asian mega-farms can cover thousands of hectares of water and generate millions of tons of seaweed each year, unlike Western seaweed farms.

“China is a really great example where you look out onto a bay and it’s seaweed or some sort of aquaculture as far as the eye can see,” says University of Maine Marine Biological Laboratory project coordinator Gretchen Grebe.

According to Danielle Blacklock, director of aquaculture at the National Oceanic and Atmospheric Administration, American seaweed producers produce less than large-scale Asian farms, even though seaweed is the fastest-growing aquaculture commodity. Montauk Seaweed Supply, a two-year-old Long Island Sound firm, works with seaweed growers to make biofertilizer, an environmentally beneficial alternative to synthetic fertilizers. Grebe thinks this is still a niche business, unlike Asian farms.

However, if seaweed farms proliferate across the West, the latest Nature study shows significant environmental advantages. The researchers analyzed the global development of large-scale seaweed farming between now and 2050, considering five potential scenarios with varied amounts of seaweed use for human meals, livestock feed, and biofuel generation.

Red seaweed for cattle feed may cut yearly carbon emissions by 2.6 gigatons, equivalent to removing almost 570 million automobiles off the road. 10% seaweed in human diets would save 110 million hectares of terrestrial agriculture. Seaweed might minimize fertilizer consumption and nutrient contamination because most biofuels are derived from terrestrial crops like maize and sugarcane.

However, certain payoffs are unrealistic. Spillias says he would be astonished if any of these eventualities happened in 2050. Globally increasing seaweed consumption by 10% is challenging. He claims seaweed is a mainstay in East Asia, yet the typical individual barely eats 2% of it. Western seaweed consumption would need a major cultural shift to match Asian levels.

Montauk Seaweed Supply co-founder Sean Barrett claims the firm still utilizes kelp to make fertilizer rather than meals. After three years in the food sector, he switched to fertilizer. He claims Americans aren’t used to consuming macroalgae, so they were resistant.

Experts also note biofuel uptake challenges

“The amount [of seaweed] that needs to be produced to make it economically viable to do biofuels is a scale that we have not come close to in the United States,” says NOAA’s Blacklock. Cost is second. Duke University’s Marine Algae Industrialization Consortium is developing a $5-per-gallon algae-based biofuel. Seaweed fuels would struggle to compete with $2.16-per-gallon ethanol even at that lower price.

Scaling global seaweed farming at Spillias’ rate may bring environmental advantages, but it may also pose problems. Farmers and businesspeople worry about invading seaweeds. Barrett of Montauk Seaweed said the seaweed farming community is “raging” about whether non-native seaweeds can be grown responsibly. He said farmers want to cultivate new crops as the sector grows.

Farmers may want to import non-native species to increase output, but this might impair the local environment. Barrett said cultivating California’s bull kelp in New York, where sugar kelp is the major native species, might harm native sugar kelp populations by competing for space and resources.

NOAA’s rigorous vetting process also excludes places with endangered species, vulnerable ecosystems, or corals. Blacklock calls this siting procedure “everything”. In a coral reef, adding seaweeds can restrict nutrients, sunshine, and space.

“You can’t just plop a farm down,” says Grebe of the University of Maine. Seaweed farms may benefit the environment and economy. Grebe’s kelp farm attracted hundreds of Caribbean spiny lobster, making it their home. Grebe said local fishermen prize these lobsters, which may create new economic options in an unfished area. Siting a kelp farm properly reduces environmental impact and maximizes community benefits.

Spillias says that while models like his can show how seaweed aquaculture might expand globally, it will take years of study, entrepreneurship, and cultural change to do so sustainably.