Why 96% of reef ecoregions are rated critically endangered—and why that is not 96% collapse
WHAT THE EVIDENCE SAYS
A 22 October IUCN assessment classified 122 of 127 assessed ecoregions (96%) Critically Endangered under an integrated analysis that includes future heat-stress projections. Using observed change alone, 116 (91%) were threatened and 30 (24%) Critically Endangered; one western Galápagos ecosystem was assessed Collapsed and four data deficient.
WHY IT MATTERS / OUR READ
The decision-relevant headline is the narrowing recovery interval under repeated marine heatwaves, not a claim that all assessed reefs have already stopped functioning. Monitoring must separate present ecological structure, function and projected collapse risk.
CAVEATS / UNCERTAINTY
Risk categories are not observed collapse. The 96% designation is sensitive to the future-climate scenario (SSP2-4.5) and assessment criteria; ecosystem-level results differ from species-level coral Red List findings.
SOURCE
IUCN Red List of Ecosystems — Global Coral Reef Assessment (22 Oct 2026)
View original evidence ↗
The IUCN's first global reef ecosystem Red List separates observed damage from modeled future warming risk.
Read the Wild Lands assessment →