Alarming Coral Bleaching in the Great Barrier Reef

The Great Barrier Reef in Australia has suffered the most extensive coral bleaching ever recorded, according to a government report.

The measurements have been ongoing for 40 years. Coral bleaching occurs as a result of increased sea temperatures and causes the microorganisms that live in symbiosis with the coral animals to move away from the corals. The corals then turn white and die.

The Australian Institute of Marine Science monitored the health of 124 coral reefs in the Great Barrier Reef between August 2024 and May 2025, when record high sea temperatures last year led to ‘unprecedented levels of heat stress’.

The report now shows that the northern and southern parts of the reef have suffered ‘the largest annual decline in coral cover’ ever recorded. The reef has been ravaged by tropical storms and attacked by sea urchins that eat coral.

But the main reason for the spread of coral bleaching is climate change, according to Mike Emslie, who led the study.

There is no doubt about that, he says.
The bleaching now observed in the Great Barrier Reef is the sixth in nine years. However, scientists believe that the coral growth that has occurred at the same time will compensate for the loss.
According to the scientists, it will take several years of coral growth and minimal environmental impact for the Great Barrier Reef to recover.

^{Cover image: Part of the Great Barrier Reef photographed in 2022. Photo: Sam McNeil/AP/TT}