Australia’s Great Barrier Reef suffers 6th mass bleaching event

SYDNEY, Australia – A huge swath of the Great Barrier Reef has been hit by a sixth mass bleaching event, the marine park authority announced on Friday, an alarming milestone for the coral wonder that underscores the continuing threat of climate change. and greenhouse gas emissions. .

Government scientists who used helicopters and small planes to inspect 750 separate reefs over hundreds of miles last week found severe bleaching among 60% of corals.

Bleaching events have now happened in four of the past seven years, with 2022 providing a worrying first – a massive bleaching in a La Niña year, when more rain and cooler temperatures were supposed to offer a moment of respite for sensitive corals to recover. to re-establish.

“We find that coral reefs cannot cope with the current rate of warming and frequency of climate change,” said Dr Neal Cantin, a coral biologist who led one of the teams observing the state of the reef. reef. “We need to slow this rate of warming as quickly as possible.”

Coral bleaching is often called a climate change warning system, a canary in the coal mine of a troubled land. This indicates that the corals are under intense stress from the waters around them, which have not ceased to warm up. Last year scientists recorded the warmest year on record for the world’s oceans – for the sixth consecutive year.

First, stress appears on coral reefs in bright, almost neon colors, as the coral, which is an animal, pushes out the algae that live inside it and provides food for the coral. Corals turn bone-white but can still recover if temperatures cool for a long enough period.

However, scientists report that has become increasingly rare. Between 2009 and 2019, a scan study since last year, 14% of the world’s coral reefs have been lost.

Along the 1,500 miles of the Great Barrier Reef – a stunning ecosystem that can be seen from space – there are still large, healthy sections of coral, with sharks, turtles, rays and fish from around the world. color pencils.

But throughout the natural wonder, there are also signs of damage. The undersea graveyard blocks, with gray fields of dead, brittle coral covered in ugly wisps of algae, have grown with each mass bleaching since the first in 1998.

In Australia, this decline has become increasingly politicized. Prime Minister Scott Morrison’s government, which has done little to reduce the country’s dependence on fossil fuels or its exports, has repeatedly pushed the United Nations to defy its own scientific opinion and prevent the reef from being placed on a list of endangered World Heritage Sites.

Instead of aggressively pursuing emissions reductions, Australia has spent hundreds of millions of dollars to long term projects that aim to help the reef by cleaning up agricultural runoff, killing invasive species, or finding and growing the most heat-tolerant species of coral.

Climate protests across the country have also intensified, some run by childrenothers by militants who tried to block trains and traffic.

UN scientists are now in Australia to check the condition of the reef. Dr Cantin said he met with them on Friday afternoon and explained to them what the polls had revealed.

The image of the reef (and its management by Australia) risks being seriously tarnished if the United Nations suggests that it is slowly heading towards extinction. But the damage to the world’s reefs goes far beyond threats to tourism or a country’s reputation.

While coral reefs cover a tiny fraction of the ocean floor, they collectively support an estimated $2.7 trillion a year in goods and services around the world, according to a recent report by the International Coral Reef Initiative. Their fish provide food for hundreds of millions of people around the world – and in Australia and elsewhere they provide protection from the severe storms that are also becoming more frequent with climate change.

Dr Cantin said he was particularly disappointed with the spatial footprint of this year’s bleaching damage. Reefs closer to shore saw the most extreme bleaching, but he said the bleaching appeared to cover a wider area than back-to-back outbreaks in 2016 and 2017.

He said it was the product of a summer that started early.

“In December, we were already warmer than February’s historic summer highs,” he said. There was a cool spell in February, he added, but the last two weeks of that month saw little rain and continued heat.

“With the frequency of large, stressful summers, we have monitored bleaching almost every year,” he said. “We are in a worrying time.”