New Delhi, Aug. 7 -- 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.

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.

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 th...