The Great Barrier Reef is experiencing its third consecutive mass bleaching event as ocean temperatures reach record levels for the Southern Hemisphere autumn. Aerial surveys show bleaching affecting over 80% of the reef system, the worst extent ever recorded.
Water temperatures around the reef have exceeded the bleaching threshold of 1°C above the long-term maximum for eight consecutive weeks. The sustained heat stress is causing not just bleaching but mortality in some coral species, threatening the reef's ability to recover.
The event is part of a global coral crisis, with bleaching reported across the Caribbean, Indian Ocean, and Pacific simultaneously. NOAA has declared the fourth global bleaching event, following previous events in 1998, 2010, and 2023-24.
Scientists warn that if ocean temperatures continue their current trajectory, coral reefs as we know them may not survive beyond mid-century. Reefs support 25% of marine species and provide food and coastal protection for 500 million people worldwide.
Restoration efforts continue but cannot keep pace with the scale of damage. Researchers are focusing on identifying heat-resistant coral strains that might survive in warmer waters, and on reducing local stressors like pollution and overfishing that compound bleaching damage.
