Food, feed and fuel: the global seaweed industry could reduce the land needed for agriculture by 110 million hectares, according to a study | Food

An area of ​​ocean nearly the size of Australia could support commercial kelp farming around the world, providing food for humans, feed supplements for livestock and alternative fuels, according to new research.

Seaweed farming is a nascent industry globally, but research says that if it could grow to make up 10% of the human diet by 2050, it could reduce the amount of land needed for food by 110 million hectares (272 million acres), an area twice the size of France.

But the research authors said there are a variety of potential negative impacts on marine life that will need to be balanced against the benefits of a global kelp farming industry.

The study looked at 34 species of seaweed and where they could feasibly grow and then narrowed them down to locations with calm enough water and close enough to populations where farms could be established.

Approximately 650 million hectares (1.606 million acres) were identified as plausible for kelp farming, with the largest areas in Indonesia and Australia, which have large ocean regions under their economic control.

“Growing kelp for food, fodder and fuel within even a fraction of the 650 million hectares of suitable ocean could have profound benefits for land use, emissions reduction, water and fertilizer use,” the researchers wrote. authors.

Scott Spillias, a researcher at the University of Queensland in Australia who led the study published in Nature SustainabilityHe said: “People around the world see the ocean as a great ‘untapped’ resource and wonder if we should use it more.”

One of the biggest benefits, the study said, would be the cultivation and use of red Asparagopsis as a livestock feed supplement that has been shown to dramatically reduce methane emissions from cows. An algae-based supplement Reportedly, it went on commercial sale. to farmers in Australia last year.

The study suggested cuts in methane emissions from the use of Asparagopsis could save 2.6 billion tons of CO2 equivalent per year by 2050, about the same as India’s current greenhouse gas footprint.

Spillias said introducing more seaweed into the human diet could also bring benefits. In parts of Asia, seaweeds make up 2% of the diet, but scaling this up to 10% globally could save 110 million hectares of land currently used to grow food.

“Basically, it’s about people eating more vegetables,” he said. “If we grow seaweed, the best we can do is get people to eat it instead of feeding it to livestock, but that will require big cultural changes.”

The nine authors, from Australia and Austria, said more work is needed to understand the costs and benefits of any boom in kelp farming, but “the magnitude of the potential benefits supports the idea that kelp farming in the ocean can play a critical role in our response to global sustainability challenges.”

A 2019 review of the risks of expanding seaweed farming in Europe Raised farm concerns could upset the balance of marine ecosystems and could alter the way water moves around shorelines.

“Converting even a few million hectares means a huge amount of development,” Spillias said. “We are modifying habitats and introducing materials in places where we have not been before.

“Much of the kelp farming now uses plastic ropes and nets and we know the impacts of plastic in the ocean. If this is done on a large scale, we need to find better materials.”

He said that if there was a large-scale push globally for seaweed farming, there could be social implications.

“The marine industries do not have a great reputation for human rights and if we are farming seaweed largely out of sight, then we need to think about the people in these industries and make sure they are treated fairly,” he said.

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