Few ecological crises capture the severity of climate change like the loss of Earth’s coral reefs. Global coverage of living corals has already declined 50% since the 1950s, largely due to rising ocean temperatures and worsening marine heatwaves. A new report shows just how dire this situation will become if global warming continues unabated.

Scientists with the International Union for the Conservation of Nature’s Red List of Ecosystems have assessed the world’s shallow coral reefs for the first time, and the findings are stunning. The analysis—spanning 127 reef ecosystems across more than 80 countries and territories—shows that 96% are now critically endangered and face an extremely high risk of collapse in the next 50 years.

“Corals carry a deep evolutionary record of coping with environmental change, yet the reef ecosystems we see today are remarkably young, shaped over only the last 5,000 to 7,000 years of stable climate,” Marcos Valderrábano, program manager for IUCN’s Red List of Ecosystems, said in…