As the Amazon burns, there’s growing interest in cultivating forests that absorb planet-warming carbon emissions, but that are fireproof.
That’s because these forests are underwater.
An increasing body of research is documenting the potential of seaweed farming to counter climate change as deforestation decimates rainforests and other crucial carbon sinks. Fast-growing oceanic jungles of kelp and other macroalgae are highly efficient at storing carbon. Seaweed also ameliorates acidification, deoxygenation, and other marine impacts of global warming that threaten the biodiversity of the seas and the source of food and livelihoods for hundreds of millions of people.
“Seaweed is finally having its moment in the spotlight,” says Halley Froehlich, a marine scientist at the University of California, Santa Barbara.
She is the lead author of a new study that for the first time quantifies the global capacity of large-scale seaweed farming to offset terrestrial carbon emissions and maps areas of the ocean suitable for macroalgae cultivation.
Farming seaweed in just 3.8 percent of the federal waters off the California coast—that’s 0.065 percent of the global ocean suitable for growing macroalgae—could neutralize emissions from the state’s $50 billion agriculture industry, according to the paper published Thursday in the journal Current Biology.
Seaweed is currently grown on a small scale for use in food, medicines, and beauty products. The scientists, however, propose the establishment of industrial-size farms to grow seaweed to maturity, harvest it, and then sink it in the deep ocean where the captured carbon dioxide would be entombed for hundreds to thousands of years.
They found that raising macroalgae in just 0.001 percent of seaweed-growing waters worldwide and then burying it at sea could offset the entire carbon emissions of the rapidly growing global aquaculture industry, which supplies half of the world’s seafood. Altogether, 18.5 million square miles of the ocean is suitable for seaweed cultivation, the study concluded.
There’s a catch
“The technology doesn’t yet exist” to sequester seaweed in the deep ocean, notes Froehlich. “Hopefully this paper spurs conversation among engineers and economists about what would it take for the actual mechanisms to be put in place.” (...)
Beyond seaweed’s potential to counteract acidification and deoxygenation, absorb excess nutrients and provide habitat for marine life in at least 77 countries, seaweed can be processed into biofuel. And research has shown that adding seaweed to livestock feed can reduce potent methane emissions from the burps of cows and other grazing livestock—a significant source of global greenhouse gases—by as much as 70 percent. Seaweed can also be used as an agricultural soil supplement, replacing petroleum-based fertilizers.
“The math shows you that seaweed can be a very effective tool to fight climate change, but it has to be validated by the market,” says Scotty Schmidt, chief executive of Primary Ocean, a Los Angeles company working on a United States government-funded project to develop technologies to deploy large-scale seaweed farms.
“Farming seaweed just for carbon sequestration is not a viable business case at this time as there's barely a carbon market that's willing to accept seaweed offset credits,” he says.
That’s because these forests are underwater.
An increasing body of research is documenting the potential of seaweed farming to counter climate change as deforestation decimates rainforests and other crucial carbon sinks. Fast-growing oceanic jungles of kelp and other macroalgae are highly efficient at storing carbon. Seaweed also ameliorates acidification, deoxygenation, and other marine impacts of global warming that threaten the biodiversity of the seas and the source of food and livelihoods for hundreds of millions of people.
“Seaweed is finally having its moment in the spotlight,” says Halley Froehlich, a marine scientist at the University of California, Santa Barbara.She is the lead author of a new study that for the first time quantifies the global capacity of large-scale seaweed farming to offset terrestrial carbon emissions and maps areas of the ocean suitable for macroalgae cultivation.
Farming seaweed in just 3.8 percent of the federal waters off the California coast—that’s 0.065 percent of the global ocean suitable for growing macroalgae—could neutralize emissions from the state’s $50 billion agriculture industry, according to the paper published Thursday in the journal Current Biology.
Seaweed is currently grown on a small scale for use in food, medicines, and beauty products. The scientists, however, propose the establishment of industrial-size farms to grow seaweed to maturity, harvest it, and then sink it in the deep ocean where the captured carbon dioxide would be entombed for hundreds to thousands of years.
They found that raising macroalgae in just 0.001 percent of seaweed-growing waters worldwide and then burying it at sea could offset the entire carbon emissions of the rapidly growing global aquaculture industry, which supplies half of the world’s seafood. Altogether, 18.5 million square miles of the ocean is suitable for seaweed cultivation, the study concluded.
There’s a catch
“The technology doesn’t yet exist” to sequester seaweed in the deep ocean, notes Froehlich. “Hopefully this paper spurs conversation among engineers and economists about what would it take for the actual mechanisms to be put in place.” (...)
Beyond seaweed’s potential to counteract acidification and deoxygenation, absorb excess nutrients and provide habitat for marine life in at least 77 countries, seaweed can be processed into biofuel. And research has shown that adding seaweed to livestock feed can reduce potent methane emissions from the burps of cows and other grazing livestock—a significant source of global greenhouse gases—by as much as 70 percent. Seaweed can also be used as an agricultural soil supplement, replacing petroleum-based fertilizers.
“The math shows you that seaweed can be a very effective tool to fight climate change, but it has to be validated by the market,” says Scotty Schmidt, chief executive of Primary Ocean, a Los Angeles company working on a United States government-funded project to develop technologies to deploy large-scale seaweed farms.
“Farming seaweed just for carbon sequestration is not a viable business case at this time as there's barely a carbon market that's willing to accept seaweed offset credits,” he says.
