Story highlights Out of the three bleaching events on the reef, this was the most severe

It could take up to 15 years for the coral to regrow

(CNN) Coral across Australia's Great Barrier Reef has suffered its most devastating die-off on record, a new report says.

In just nine months, bleaching caused by warmer water has killed around 67% of the coral in a previously pristine part of the reef, one of the natural wonders of the world.

"We've seen three bleaching events (in the reef) and each time it can be explained by where the warm water was," the report's author, ARC Center of Excellent for Coral Reef Studies Director Terry Hughes, told CNN.

"In the north, the summer temperatures got up to two degrees above the normal maximum and that caused severe bleaching," he said.

Extensive aerial surveys and teams of divers were used to map the bleaching, which covered a length of 700 kilometers.

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