Overview
- Published in Nature Communications, the synthesis identifies the 2014–2017 event as the most severe and widespread coral bleaching on record.
- The team combined NOAA Coral Reef Watch satellite heat-stress data with more than 15,000 in‑water and aerial surveys, supported by nearly 200 co-authors from 143 institutions in 41 countries.
- Coral Reef Watch introduced new, higher alert levels during the 2014–2017 crisis as heat stress repeatedly hit many locations, limiting recovery on reefs such as the Great Barrier Reef.
- Scientists report the Fourth Global Bleaching Event began in early 2023, with 2023–2024 heat stress comparable to or higher than 2014–2017 in some areas, including documented mortality along Panama’s Pacific coast.
- The study underscores that ocean warming is accelerating bleaching frequency, extent and severity, heightening ecological risks and threatening the fisheries, coastal protection and tourism services reefs provide.