A global study has revealed that more than half of the world’s coral reefs were bleached between 2014 and 2017, in what scientists are calling the “Third Global Bleaching Event.” The analysis found that 51% of reefs experienced moderate or worse bleaching, while 15% suffered significant mortality, making it the most severe and widespread coral bleaching event on record.

Unlike previous one-year events in 1998 and 2010, this bleaching lasted three years, leaving reefs with little time to recover. Researchers warn that rising ocean temperatures, combined with repeated heat stress, are accelerating coral decline worldwide.

“The impacts of ocean warming on coral reefs are accelerating, with large-scale, possibly irreversible degradation likely if trends continue,” said Dr. Sean Connolly of the Smithsonian Tropical Research Institute. Early evidence suggests that the current fourth global bleaching event, ongoing since 2023, is even more intense in some regions.

Australia’s Great Barrier Reef, along with reefs in Panama and across the tropics, has experienced repeated high heat stress, highlighting the urgent need for climate action to protect these critical marine ecosystems.

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