Seaweed carbon removal vs kelp loss: study finds restoring and farming kelp cannot outpace climate-driven losses

A new study from researchers in Australia and Canada argues that climate change is destroying kelp forests far faster than restoration or farming can rebuild their carbon sink. The authors estimate climate-driven kelp loss releases or forgoes about 13 million metric tons of CO2 per year, while verified wild kelp restoration since 1958 covers only about 4,200 hectares. That leaves a 1,000 to 10,000 times gap between losing natural sequestration and adding it back through intervention. The study also warns against treating seaweed farming as a large-scale carbon dioxide removal method. In nine of eleven farms assessed, operations emit more CO2 than the farm buries. Farming seaweed can still be useful for food, materials, and replacing high-carbon goods, but it is not a climate-scale offset solution. Protecting existing kelp forests is far cheaper than restoring them, and the authors argue that cutting emissions is the real fix. The takeaway for carbon markets is simple: do not sell offsets against weak seaweed CDR while the existing natural sink is collapsing.