Scientists say world’s coral reefs experiencing mass bleaching in warming oceans
- Surging ocean temperatures trigger second global coral bleaching event in a decade
- This year’s bleaching follows declaration that 2023 was the hottest year on record

Coral reefs around the world are experiencing global bleaching for the fourth time, top reef scientists declared, a result of warming ocean waters amid human-caused climate change.
Coral reef bleaching across at least 53 countries, territories or local economies has been confirmed from February 2023 to now, scientists from the National Oceanic and Atmospheric Administration and International Coral Reef Initiative said.
It happens when stressed coral expel the algae that are their food source and give them their colour. If the bleaching is severe and long-lasting, the coral can die.
Coral reefs are important ecosystems that sustain underwater life, protect biodiversity and slow erosion. They also support local economies through tourism.

Bleaching has been happening in various regions for some time. In the world’s largest coral reef ecosystem, Australia’s Great Barrier Reef, bleaching affected 90 per cent of the coral assessed in 2022.
The Florida Coral Reef, the third-largest, experienced significant bleaching last year.