I.U.C.N. Red List Classifies Most Shallow Coral Reefs as Critically Endangered

Almost all of the world’s shallow-water coral reefs, famous for their riot of color and life, have now been classified as critically endangered by experts who assess ecosystem collapse. Heat stress because of climate change is the overwhelming reason for the finding, announced Thursday by the International Union for Conservation of Nature’s Red List of Ecosystems. It was the group’s first global assessment of shallow-water reef ecosystems. The scientists grouped reefs into 127 regions based on location and the unique species present. They found that 96 percent were critically endangered, including those in the Great Barrier Reef off Australia, the Coral Triangle in the western Pacific, the Mesoamerican Barrier Reef System in the Caribbean and Florida’s reefs. The classification means that they face an extremely high risk of collapse within 50 years. The I.U.C.N. defines collapse as the near or complete loss of living hard corals, leaving reefs unable to sustain themselves. Shallow-water reefs support around a quarter of ocean species at some point in their life cycle, scientists estimate. Hundreds of millions of people rely on these ecosystems for fish and coastal protection. Scientists involved in the research emphasized that the reefs are not yet lost. The finding is based on the current estimated trajectory of climate change, given global greenhouse gas emissions primarily from the burning of oil, gas and coal. If countries do more to slow warming, the outcome for reefs could improve. We are having trouble retrieving the article content. Please enable JavaScript in your browser settings. Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times. Thank you for your patience while we verify access. Already a subscriber? Log in . Want all of The Times? Subscribe .