Severe coral bleaching to hit the Great Barrier Reef

“It’s pretty sad, she said. “There’s been bleaching many times since the big event in 2016, but none of them have progressed as much as this one.”

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The past eight years have been filled with coral bleaching events along the Great Barrier Reef, with the worst one occurring in 2016. The 2021 and 2022 summer was the first time the reef had bleached during a La Nina year.

The outlook for the Great Barrier Reef over the summer looked grim, and reef scientists were concerned. After all, coral reefs in the Northern Hemisphere were bleached in the worst event just months earlier – up to 95 per cent of corals they surveyed at 76 sites across the Florida Keys and Dry Tortugas over a week showed signs of extreme bleaching.

As Australia’s summer drew closer, reef scientists were concerned the same thing would occur along the Great Barrier Reef. But when two tropical cyclones occurred, the concern subsided – slightly, WWF Australia head of oceans Richard Leck said.

But as the summer months drew closer and two tropical cyclones occurred, the threat of heat stress and coral bleaching minimised. While tropical cyclones pose their own risk to coral reefs, Leck added.

“The consensus was that we got through another season without a major bleaching event. Then all of a sudden, it feels like we are on a knife’s edge,” he said.

“We have got really concerning high temperatures over a large part of a Great Barrier Reef and we still have a large number of weeks to get through before temperatures traditionally cool down.

“We shouldn’t be having the threat of a mass coral bleaching this year.”

“The advice has always been when you have big storms like we’ve had, you traditionally don’t get coral bleaching. The conditions are changing.”

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Bleaching is forecast to reduce global coral cover by 95 per cent under 2 degrees of warming, and 70 per cent under 1.5 degrees. If all countries deliver on their climate commitments, the world would still be on track for 2 degrees or more of warming. If the rest of the world followed Australia’s current commitments and policies, global warming would exceed 3 degrees, according to Climate Action Tracker.

But Leck said that recent actions from the federal and local governments were cause for hope, but more needed to be done as climate change continues to warm the environment, placing more stress on coral reefs.

Srinivasan added despite the bleaching she’d witnessed, coral reefs could recover.