Australia’s Great Barrier Reef suffers sixth episode of mass bleaching


The Great Barrier Reef Marine Park Authority (GBRMPA) and the Australian Institute of Marine Science (AIMS) said on Friday that aerial surveys of around 750 reefs show widespread bleaching across the reef, with the most severe bleaching seen in the northern and central areas.

“More than half of the live coral cover we can see from the air is completely bleached and may show signs of fluorescence in colors pink, yellow and blue,” said AIMS coral biologist Neal Cantin.

“Corals produce these fluorescent pigments in an attempt to protect their tissues from the heat and intense sunlight during these sea heat waves.”

The latest bleaching event comes despite La Niña, a weather system that generally creates more movement in the water and increases rain and cloud cover, helping to reduce average maximum temperatures.

It is the fourth massive bleaching in six years and the first since 2020, when around a quarter of the reef surveyed showed signs of severe bleaching. This event came just three years after consecutive bleaching episodes in 2016 and 2017. Previous bleachings occurred in 1998 and 2002.

GBRMPA chief scientist David Wachenfeld said the coral was stressed but not dead.

“If the water temperature drops, bleached corals can recover from this stress. It’s important to remember that we had a massive bleaching event in 2020, but coral mortality has been very low,” he said. said Wachenfeld.

Wonder of threatened nature

Australia’s Great Barrier Reef stretches 2,300 kilometers along the Queensland coast. Before the pandemic forced the closure of borders, it attracted around three million tourists each year.

This year, aerial surveys with helicopters and fixed-wing aircraft have shown that the worst of the bleaching is near Townsville. Tourist areas near Cairns and Port Douglas were less affected due to lower levels of heat stress.

Bleaching occurs when stressed coral ejects algae from within its tissues, depriving it of a food source. If conditions do not improve, the coral may starve and die, turning white when its carbonate skeleton is exposed.

“Even the hardiest corals take nearly a decade to recover,” said Jodie Rummer, associate professor of marine biology at James Cook University in Townsville.

“So we’re really losing that recovery window. We have back-to-back bleaching episodes, back-to-back heat waves. And the corals just aren’t adapting to these new conditions,” she said. .

The Australian government has come under pressure from UNESCO to prove it is doing enough to save the reef.

Earlier this year, the Australian government pledged A$1 billion ($700 million) over 10 years to support new climate adaptation technologies, investment in water quality programs and protection of the main reef species.

While the extra funding has been welcomed, the government has been called out by global climate experts and others for not doing enough to move Australia away from fossil fuels.

The Climate Action Tracker gives the country a “very poor rating” for its action on climate change. “The government seems determined to replace fossil fuels with fossil fuels,” he said, citing the government’s “gas-driven recovery” program announced in 2020 to pull the country out of an economic downturn linked to the spread of Covid-19.

On Monday, United Nations chief Antonio Guterres cited Australia among a “handful of holdouts” in the group of G20 countries that had not announced “meaningful emissions cuts”.
The Great Barrier Reef Marine Park Authority has just completed aerial surveys of all 3,000 reefs in the reef system.

He said countries and private companies investing in coal are costing the world its climate goals. And he said the money spent on fossil fuels and subsidies was “dumb investment leading to billions in stranded assets”.

“It’s time to end fossil fuel subsidies and stop the expansion of oil and gas exploration,” he said.

Amanda McKenzie, CEO of the Climate Council, said the real problem the government should be tackling is climate change.

“To give our reef a fighting chance, we need to address problem number one: climate change. No amount of funding can stop these episodes of bleaching unless we reduce our emissions this decade,” she said in a statement.


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