Kelp conservation challenges the seaweed carbon-removal pitch

A new study argues that cultivating seaweed is being overstated as a climate solution because carbon released through seaweed loss may exceed the amount absorbed by new cultivation.[3] With about 60 per cent of kelp forests in decline, the researchers say conservation should take priority, although another scientist argues that uncertain sequestration estimates make it premature to dismiss restoration and farming.[3] Why it matters: Governments, researchers and companies considering seaweed for emissions offsets need to account for losses from existing kelp forests rather than counting only carbon captured by new projects.[3] Key insights: Declining kelp ecosystems could eventually emit more CO2 than they absorb, according to Karen Filbee-Dexter and colleagues.[3] | Pamela Walsh argues that macroalgae conservation, restoration and farming may still contribute to climate action despite previously exaggerated claims.[3] | The disagreement centres partly on the lack of a sufficiently firm estimate of how much carbon seaweed actually sequesters.[3] Cheatsheet facts: What changed: The study shifts attention from expanding seaweed cultivation to preventing carbon losses from declining kelp forests.[3] | Why now: About 60 per cent of kelp forests are in decline, raising concern that ecosystem losses may outweigh cultivation gains.[3] | Watch next: Watch for stronger measurements of carbon sequestration by seaweed and the net carbon balance of declining, restored and farmed macroalgae.[3]