Higher water temperatures in 2016 caused the worst destruction of corals ever recorded on Australia’s Great Barrier Reef, a study has found.

Some 67% of corals died in the reef’s worst-hit northern section, the ARC Centre of Excellence for Coral Reef Studies report said.

The situation was better in the central section, where 6% perished, while the southern reef is in good health.

But scientists warn recovery could be difficult if climate change continues.

Coral bleaching happens when water temperatures rise for a sustained period of time.

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In February, March and April, sea surface temperatures across the Great Barrier Reef were the hottest on record, at least 1C higher than the monthly average.

“Some of the initial mortality was down to heat stress,” said study leader Professor Terry Hughes.

“The coral was cooked.”

How bleaching occurs

Far more has been lost through gradual starvation, after the coral expelled the colourful algae zooxanthella, which turns sunlight into food.

This is what leads to the white, skeletal appearance of the coral, which is left without its main source of energy.