The International Union for Conservation of Nature (IUCN) has published its first worldwide assessment of coral reef ecosystems, rating 96% of the assessed shallow-water reef ecosystems as Critically Endangered. It covers 188,362 sq km of reefs in 127 tropical and subtropical ecoregions in over 80 countries and territories. Climate-driven heat stress (ocean warming, marine heatwaves, bleaching) is the top threat. Overfishing, pollution, coastal development and excess tourism add to the damage; depleted fish stocks threaten 63% of reef ecosystems. Major systems such as the Red Sea reefs, the Coral Triangle, the Great Barrier Reef and the Mesoamerican Barrier Reef fall in this category. Reefs host about 25% of marine species; stronger climate action and targeted conservation could still avert further collapse.
