Caribbean reefs have lost 48% of hard coral since 1980, study finds

"The 48% decrease in coral cover has been driven by climate breakdown, specifically marine heatwaves. They affect the microalgae that feed coral, making them toxic and forcing the coral to expel them. In 2023-24, the region's coral experienced the most destructive thermal stress ever recorded, said Dr Jeremy Wicquart of the Global Coral Reef Monitoring Network, one of the study's editors."

"Forty years ago, a diver would have seen a colourful, vibrant ecosystem that nurtured hundreds of marine species such as spiny lobsters, queen conchs, parrotfish, turtles and sharks. Coral reefs cover less than 1% of the world's seafloor, but support at least 25% of marine species. But when Wicquart went diving last year after a conference in Puerto Morelos, Mexico, he was met with bone-white, dying coral."

Caribbean hard coral cover has fallen roughly 48% since 1980, with an especially severe 16.9% year-on-year loss in 2023–24 due to unprecedented thermal stress. Marine heatwaves disrupt symbiotic microalgae that feed and colour corals, making the algae toxic and triggering bleaching and higher mortality. Cyclones physically destroy reef structures, converting coral to rubble. Macroalgae coverage has risen about 85% since 1980, flourishing where coral has declined and where herbivorous fish have been overfished. Caribbean reefs support at least 25% of marine species and generate about $6.2bn annually from fisheries and tourism, with reef tourism accounting for roughly 10% of regional GDP. Conservation actions show localized recovery and offer pathways for resilience.

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