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Climate change is driving rapid declines in seaweed forests globally, outpacing restoration efforts and undermining seaweed restoration as a viable carbon dioxide removal strategy, according to an essay by Karen Filbee-Dexter at the University of Western Australia, and colleagues, publishing September 8th in the open access journal PLOS Biology.
Natural ecosystems have played an important role in mitigating greenhouse gas emissions over the last century by absorbing carbon dioxide from the atmosphere, but this vital ecosystem service is being jeopardized by climate change itself. Planting and restoring seaweed forests is often promoted as a natural climate solution due to their ability to sequester carbon and store it in the deep ocean. However, declines in seaweed forests globally threaten to undermine restoration efforts.
Researchers analyzed published data on global seaweed forest gains and losses to estimate the net effect on carbon sequestration. They found that declines in kelp forests — the most widespread and productive seaweed ecosystem — could result in a reduction in natural carbon sequestration of 1.5 to 30 million tons per year. This loss is between 1,000 and 10,000 times greater than the gain in annual carbon dioxide sequestration from kelp forest restoration projects to date.
