Australia’s Great Barrier Reef, more threatened than ever

Anne Hoggett, who has been diving for decades near the Great Barrier in northeastern Australiaconfirms, with fury, the massive bleaching of corals caused by the climate change.

“It makes me angry to know that we have the power to prevent it and we don’t do anything fast enough,” underlines this marine biologist who, for thirty-three years, has lived and worked on Lagarto Island, near the largest coral reef in the world.

The latter stretches for more than 2,300 kilometers along Australia’s northeast coast and is home to some 1,600 species of fish and 600 types of coral.

Hoggett regularly dives among schools of fish that seek shelter and food there. But the site looks like a cemetery due to the new episode of mass bleaching that devastates this ecological jewel.

This phenomenon is caused by an increase in water temperature that causes the expulsion of the symbiotic algae that give the coral its bright color.

Since February, underwater temperatures around Lizard Island have been 2°C above average. As a consequence, around 80% of the corals died, according to the biologist.

Maybe “they suffered too much damage to be able to regenerate”she comments worriedly.

Announced in March by Australian authorities, this new episode of mass bleaching is the fifth in eight years.

According to aerial surveys, it affects more than 600 reefs locally, and 10% of the Great Barrier Reef is experiencing extreme bleaching, permanently compromising the life chances of most of its corals.

The phenomenon is not limited to Australia. On Monday, the US Oceanic and Atmospheric Observing Agency (NOAA) announced that the planet was experiencing its second largest coral bleaching event in ten years.

““Coral bleaching is becoming more frequent and serious,” said Derek Manzello, coordinator of NOAA’s Coral Reef Observatory, pointing to record-breaking ocean temperatures.

Climate change responsibility

When Hoggett arrived on Lizard Island in the 1990s, this phenomenon occurred every decade. But now the coral reefs surrounding the island will experience such an episode every year or almost, he warns.

According to scientists, a 2 °C increase in temperatures could cause the total disappearance of the 95% of the planet’s coral reefs.

Even if the international community’s goal, widely considered unattainable, of limiting this increase to 1.5°C compared to the pre-industrial era, was respected, 70% of coral reefs could be subject to bleaching.

Billions of dollars have been invested to try to save corals, but for scientist Terry Hughes the culprit is climate change.

“After 50 years of interventions, attempts to restore corals did not modify the ecology of a single reef”he points out.

The breeding of corals in aquariums, proposed as a possible solution, seems especially chimerical.

“It would take 250 million large corals, each the size of a dinner plate, to increase the coral cover of the Great Barrier Reef in just 1%and that would cost billions of dollars,” indicates.

The only solution is “reduce greenhouse gas emissions as quickly as possible”it states.

Australia, one of the largest emitters on the planet, has already invested more than US$3 billion to improve water quality, reduce the effects of climate change and protect endangered species.

But the country is one of the largest exporters of natural gas and coal, and only recently set goals, considered unambitious, to achieve carbon neutrality.

For Roger Beeden, scientific director of the Great Barrier Reef Marine Park Authority, it is too early to draw conclusions from this latest episode of coral bleaching.

“There are hundreds of species of corals evolving in an incredibly changing environment. They are very adaptable”, he observes hopefully.

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