The updated plan included commitments to limit the impacts of climate change on the reef, with three new goals relating to climate mitigation and adaptation, he said.

The plan is part of both governments’ response to the recommendation by UNESCO earlier this year that the reef be listed as endangered. Australia lobbied against that decision, but it will be revisited next year after a UNESCO team visits the reef.

Professor Terry Hughes, a global expert on coral reefs and bleaching and a member of the expert committee that helped draft the report, said the reef was considered at risk not only due to heating but also the impacts of industrialisation along the Queensland coast and damage caused by poor water quality.

Report cards on water quality had been produced late and suggested Australia was not on track to meet improvement targets, he said.

As the world considers the level of threat to the reef, scientists are becoming increasingly concerned about the prospect of another bleaching event by January, even though the region is experiencing a typically cooler La Nina weather pattern.

Professor Hughes said a Bureau of Meteorology update on Wednesday morning suggested bleaching could occur by the end of January or in February.

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The Coral Sea ocean temperature was about 1 degree hotter than average and the region had experienced its hottest November ocean temperatures since records began 100 years ago, he said.

“And obviously, we’re still in the early stages of summer, so NOAA [the US National Oceanic and Atmospheric Administration] and the Bureau of Meteorology are now predicting a strong chance of bleaching in January or February,” Professor Hughes said.

“If that happens, it would be unusually early sea temperatures normally peak at the beginning of March.”

But Professor Hughes said predictions made early in the season were not locked in. A heatwave could cause a bleaching and a cyclone could still cool temperatures enough to prevent one.

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He said the potential for a bleaching event during an El Nino cycle was scary, but no longer surprising.

“So we don’t need an El Nino anymore to trigger mass bleaching because the temperature keeps going up and up through cycles,” Professor Hughes said.

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