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Great Barrier Reef off the coast of Queensland
Photo: Glenn Nicholls / AFP
The ongoing heatwave in Australia has damaged more than 90 percent of the Great Barrier Reef's coral, according to a government report.
Of the 719 reefs surveyed, 654 — or 91 percent — exhibited some degree of coral bleaching.
The authority speaks of a fourth mass bleaching of the Great Barrier Reef in just seven years.
A heat wave has been raging in Australia since December.
It is the first time the reef has been affected by bleaching during a La Niña weather period, when cooler temperatures are normally expected.
Earlier this year, researchers observed signs of new coral bleaching in various parts of the reef.
As a result, in March, the responsible national park authority took aerial photos of the entire reef to record the extent of the bleaching.
Coral bleaching is a phenomenon that occurs when corals are stressed, such as by rising temperatures, and shed the colorful algae that live within them.
The damaged corals could recover as water temperatures cool.
This can be seen from the corals regaining their color.
In 2020, much of the coral would have recovered from such a mass bleaching.
The researchers are worried.
The more corals fade, the greater the likelihood that parts of the reef will weaken and die.
"Climate change is happening and the reef is already feeling the effects," the Great Barrier Reef Marine Park Authority said in a statement.
A rapid increase in sea temperature poses significant challenges to the reef.
The corals could not adapt so quickly.
Before the Australian general election in ten days, environmentalists called on politicians to do more to protect the climate.
"Although bleaching is becoming more common, it's not normal and we shouldn't put up with it," said Lissa Schindler of the Australian Marine Conservation Society.
"Both major political parties must face the fact that their climate targets are not sufficient for the reef."
Next month, Unesco's World Heritage Committee will decide whether the Great Barrier Reef should be classified as "Vulnerable".
In 2015, Australia was able to avert an impending downgrading of World Heritage by the government drawing up a long-term action plan and investing billions in protection measures.
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