Great Barrier Reef records largest annual coral loss in 39 years

The Great Barrier Reef has experienced its greatest annual loss of live coral across most of its expanse in four decades of record-keeping, Australian authorities say.

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But due to increasing coral cover since 2017, the coral deaths — caused mainly by bleaching last year associated with climate change — have left the area of living coral across the iconic reef system close to its long-term average, the Australian Institute of Marine Science said in its annual survey on Wednesday (August 6, 2025).

The change underscores a new level of volatility on the UNESCO World Heritage Site, the report said.

Mike Emslie, who heads the tropical marine research agency's long-term monitoring program, said the live coral cover measured in 2024 was the largest recorded in 39 years of surveys.