The International Union for Conservation of Nature (IUCN) released its first global assessment of coral reef ecosystems, finding that 96% of assessed shallow-water coral reef ecosystems are Critically Endangered.
The assessment covers 188,362 sq km of coral reefs across 127 tropical and subtropical ecoregions in more than 80 countries and territories.
Climate change-induced heat stress is the most dominant threat, causing ocean warming, marine heatwaves and coral bleaching.
Overfishing, pollution, coastal development and excessive tourism are also major threats; depleted fish populations threaten 63% of coral reef ecosystems.
Major reefs including the Great Barrier Reef, Coral Triangle, Mesoamerican Barrier Reef and Red Sea reefs are classified as Critically Endangered.
Coral reefs support about 25% of marine species, and the assessment notes that stronger climate action and targeted conservation could still help prevent further collapse.