Bleaching affects 98% of the Great Barrier Reef

According to the findings of a study released on Thursday, the intensity and magnitude of the ocean heat waves that cause this bleaching are increasing.

The figures are as rhetorical as they care. 98% of Australia’s Great Barrier Reef has been affected by bleaching since 1998, preserving a small portion of the world’s largest coral reef, according to a study released Thursday.

Five chapters since 1998

According to an article in the current journal Biology, Only 2% of this massive underwater environment has survived the event since the first major bleaching episode of 1998, the hottest year in history. This record was repeatedly broken.

Terry Hughes, lead author of the Australian Research Council’s Special Center for Research on Corals at James Cook University, says the frequency, intensity and magnitude of the ocean heat waves that cause this whitewash are steadily increasing.

“Since 1998, five large-scale white series have transformed the Great Barrier Reef into a checkerboard of rocks with very different recent histories.

Symptoms for healing

Bleaching is a futile event that results in discoloration. This causes the water temperature to rise, which causes the coral to expel the algae that give the coral its color and its nutrients.

The Great Barrier, a UNESCO World Heritage Site, was whitewashed in 1981 during the heat waves of 2016, 2017 and 2020.

While acknowledging that the long-term outlook for this 2300km long environment is “too bad,” the researchers confirmed in July that the corals had shown signs of healing since the last bleaching.

The rocks are threatened by hurricanes, and the increasingly occurring coral-eating starfish due to climate change and purple agglomeration, pollution and agricultural waste.

“Need some time”

Research also shows that corals that have already been subjected to heat waves are less susceptible to thermal stress, but Sean Connolly, co-author of the Smithsonian Tropical Research Institute, warns that frequent and excessive exposure reduces the resilience of rocks.

“The coral needs more time before another cycle of thermal stress to develop, dispersing, settling and resuscitating the deformed parts of the coral,” he says. “It is important to take action to control climate change.”

The study comes ahead of the UN Climate Summit in Glasgow, Scotland, where Australia, a major exporter of fossil energy, has promised to achieve carbon neutrality by 2050 and refuse to set an ambitious 2030 date.