What happened in this Energy story?

A new study argues that the push to grow seaweed as a climate solution is misguided, since declining kelp forests may eventually emit more carbon than they absorb — and preservation is far more cost-effective than cultivation.

What is a key fact in this story? (1)

**Karen Filbee-Dexter** at the University of Western Australia led a study concluding that with 60% of kelp forests in decline, these ecosystems could begin emitting more CO2 than they absorb, urging a shift toward preservation over expansion.

What is a key fact in this story? (2)

**Running Tide**, a US carbon removal start-up that raised $70 million to cultivate kelp on wooden buoys designed to sink into the deep sea, shut down last year after failing to grow kelp in the open ocean.

Study: Kelp Loss Could Turn Forests Into CO2 Sources — SkimNews

By New Scientist · Summarized & edited by Kapil Samant · 2026-09-08

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Karen Filbee-Dexter at the University of Western Australia led a study concluding that with 60% of kelp forests in decline, these ecosystems could begin emitting more CO2 than they absorb, urging a shift toward preservation over expansion.
Running Tide, a US carbon removal start-up that raised $70 million to cultivate kelp on wooden buoys designed to sink into the deep sea, shut down last year after failing to grow kelp in the open ocean.
Kelp restoration projects like a Norway experiment that poisoned sea urchins to regrow 70 hectares draw down only about 50,000 tonnes of CO2 per year — against global kelp loss emitting an estimated 14 million tonnes annually.
Preserving kelp ecosystems is at least eight times cheaper per hectare than restoring them, yet only 2% of the world's kelp forests lie in protected areas.
Seaweed farming now spans 4,000 square kilometres of ocean — roughly a third of the kelp forest area lost each year — and a separate study found nine of 11 seaweed farms emitted more CO2 than they sequestered.
Filbee-Dexter says researchers should stop asking how much carbon seaweeds can remove and instead ask how much can be prevented from being released as warming damages these ecosystems.
Pamela Walsh at Queen's University Belfast pushes back, arguing scientists lack enough data to dismiss macroalgae as a carbon sink, even if its potential has been exaggerated.

Why it matters: For governments and companies relying on seaweed to help meet net-zero pledges, the study reframes the economics: cultivation and restoration are expensive, mostly net-positive for emissions, and far slower than the rate of kelp loss. The cheaper, larger lever — protecting the 98% of kelp forests currently outside protected areas — has been an afterthought in blue-carbon policy.