Great Barrier Reef bleaching: Hundreds of coral sites experience fifth mass bleaching event in eight years

Hundreds of sites across most of the Great Barrier Reef are turning white due to heat stress in the fifth mass coral bleaching event in eight years.

Aerial surveys of more than two-thirds of the reef have confirmed “widespread” bleaching, the Great Barrier Reef Marine Park Authority said on Friday.

Climate change is the biggest threat to tropical reefs worldwide, and coral bleaching is caused by heat stress.

It is not always fatal, but corals are likely to die if temperatures remain higher than normal for too long.

Reef Authority chief scientist Roger Beeden said bleaching had been recorded at 300 locations, from Cape Melville north of Cooktown to just north of Bundaberg.

“The results are consistent with what we have seen over an extended period of time with above-average sea surface temperatures in the marine park,” Dr Beeden said.

He said there was widespread coral bleaching in shallow water on most reefs surveyed, but noted that heat stress varied by location this summer.

Reacting to the news, Federal Environment Minister Tanya Plibersek said the government has already invested $1.2 billion to save the reef.

‘We must take action against climate change. We must protect our special places and the plants and animals that call them home. And that’s exactly what we do,” she said the courier post.

‘We have legislated to achieve net zero emissions, with an emissions reduction target of 43 percent by 2030, and we have committed to achieving 82 percent renewable energy by 2030.

Dr. Lissa Schindler of the Australian Marine Conservation Society said acting now could save a $6 billion sustainable tourism industry and the 64,000 jobs created by the Great Barrier Reef.

But the bleaching mirrors what has happened to other reefs around the world in the past year.

The Australian Institute of Marine Science, which contributed to the aerial work, said teams needed to go into the water to determine the severity of the bleaching.

The Australian Marine Conservation Society said the latest mass bleaching showed the federal government must lift emissions targets and end fossil fuel projects to keep global temperatures within a survivable range for reefs.

“We need to do much more to tackle climate change, which is causing the marine heat waves that lead to coral bleaching,” Dr Schindler said.

“The former federal coalition government failed to heed the alarm sounded after four massive coral bleaching events.

‘Australia’s current target to reduce carbon pollution by 43 per cent by 2030 equates to a 2 degrees Celsius warming trajectory, which would mean the loss of 99 per cent of the world’s coral reefs.’