Rising ocean temperatures are pushing almost every shallow-water coral reef toward collapse, placing essential marine habitats in extreme danger within the next 50 years. In a new global assessment, the International Union for Conservation of Nature (IUCN) classified 96 percent of the world's coral reef systems as "critically endangered," its highest risk category, warning that total extinction is possible by 2075.
Often described as the "rainforests of the sea," coral reefs support roughly a quarter of all marine species, sustain seafood industries, and act as natural barriers against coastal erosion and storms. However, corals are extremely sensitive to heat. When ocean waters remain abnormally warm, corals suffer damaging bleaching events. If a reef collapses, the hard structures break down and are replaced by algae, rubble, and sponges, making it impossible to support a diverse ecosystem ranging from tiny invertebrates to fish like grouper.
The IUCN evaluation examined 127 tropical and subtropical systems covering more than 188,000 square kilometers. The findings include iconic locations such as Australia's Great Barrier Reef, the Western Pacific's Coral Triangle, and reefs in the Red Sea. Researchers based their projections on a scenario where global temperatures rise by 2.7 degrees Celsius above pre-industrial levels by 2100. Adding to the long-term threat of climate change, the emergence of a "super" El Niño weather pattern this year has further intensified ocean warming, Mishal Gudka, scientific lead of the assessment, reported at the UN's COP17 biodiversity summit in Yerevan, Armenia.
Despite the severe warning, the IUCN emphasized that coral reefs are not yet completely lost. Corals have demonstrated a remarkable ability to bounce back from bleaching events when given time to recover. "Pockets of surviving, resilient coral reefs can still remain in the future, so we must do everything within our reach to set them up for success," Gudka noted, urging immediate global action to protect surviving habitats.