Diver measuring kelp forest annual growth off Cape Peninsula, South Africa. Credit: Thomas Wernberg (CC-BY 4.0, https://creativecommons.org/licenses/by/4.0/)
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, published Sept. 8 in the 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 climate change itself is jeopardizing this vital ecosystem service.
Planting and restoring seaweed forests is often promoted as a natural climate solution because of their ability to sequester carbon and store it in the deep ocean. However, global declines in seaweed forests 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 million to 30 million tons per year.
