Science

Australia: techniques to “slow down by 20 years” the disappearance of the Great Barrier Reef

Making “bright clouds” and allowing corals to better withstand heat are two techniques that could slow down the disappearance of the Great Barrier due to global warming by twenty years, according to Australian scientists.

The site in north-eastern Australia, listed in 1981 as a UNESCO World Heritage Site, risks “deteriorating rapidly” in the next fifty years due to climate change, according to a study published in the journal Royal Society Open Science.

“Coral reefs are among the most climate-vulnerable ecosystems,” lead author Scott Condie told AFP.

“According to modeled projections, the proportion of corals within the reef of the Great Barrier Reef could drop below 10% within 20 years,” he said.

However, it is possible to slow this decline by adopting large-scale programs on a planetary scale, said Condie, senior researcher at the Australian National Science Agency (CSIRO).

The Great Barrier Reef has already experienced three episodes of bleaching in five years while half have disappeared since 1995 due to the rise in water temperature.

Clownfish in the corals of the Great Australian Brarrière (AFP – WILLIAM WEST)

Condie and the other authors of this article modeled the impact that the technique of making “clouds bright”, first tested last year over the Great Barrier, could have.

It consists of projecting salt crystals into the clouds to make them brighter and thus cool the waters around the reef.

They also modeled control measures against a predatory starfish species that feeds on corals and proliferates with bleaching that forces large fish to migrate away from the area.

“The results suggest that combining these measures could delay the decline of the Great Barrier Reef by two decades or more,” said Mr. Condie.

It is “urgent” to act, affirmed the scientist while recognizing that this requires work “much more important than what has been carried out so far as well as immense investments”.

The Crown of Thorns starfish, a predatory species that feeds on corals, also threatens the survival of Australia's Great Barrier Reef (AFP - GLENDA KWEK)

The Crown of Thorns starfish, a predatory species that feeds on corals, also threatens the survival of Australia’s Great Barrier Reef (AFP – GLENDA KWEK)

This modeling assumes that global temperatures will not rise above 1.8 degrees by 2100, forcing governments to meet commitments made under the Paris climate agreement.

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