A new study published in the journal PLOS Biology on September 8 warns that climate change could lead to the loss of up to 25 million hectares of kelp forests by 2050. Kelp forests are underwater ecosystems made up of large brown seaweed, often found along rocky coastlines. These forests are known for their ability to absorb carbon dioxide from the atmosphere, making them a key player in the fight against climate change. However, the study by Karen Filbee-Dexter of the University of Western Australia and her colleagues suggests that the decline of these ecosystems is happening faster than efforts to restore them, which could undermine their role in reducing atmospheric carbon. Kelp forests have been a natural way to combat greenhouse gas emissions by absorbing carbon dioxide and storing it in the deep ocean. This process, called carbon sequestration, has been a reliable part of the Earth's climate system. However, climate change is now threatening this natural process. The researchers found that the loss of kelp forests could reduce natural carbon sequestration by 1.5 to 30 million tons per year. That loss is far greater than the gains from current kelp restoration projects, which have only achieved a tiny fraction of that impact. The scale of potential kelp forest loss is staggering. By 2050, an estimated 25 million hectares of wild kelp forests—more than 6,000 times the area that has been restored since 1958—could disappear. Large-scale restoration projects, such as those in Norway and California, have required significant financial and human resources. To make up for the losses caused by climate change, tens of thousands of similar projects would be needed, potentially costing tens or even hundreds of billions of U.S. dollars. The authors of the study caution that focusing too much on seaweed restoration as a climate solution might divert attention from the more effective strategy of protecting existing kelp forests. Preventing habitat loss is both cheaper and more efficient than trying to restore it after it has been damaged. They also warn that promoting seaweed restoration could give a false sense of security, potentially slowing down efforts to phase out fossil fuels. While restoring kelp forests is valuable, the researchers argue that it cannot achieve the large-scale climate change mitigation needed to counteract rising emissions. They emphasize the need for a realistic approach to seaweed forest conservation and restoration.