Climate Crisis the 'Single Greatest Challenge' to Great Barrier Reef as Marine Treasure Suffers New Mass Bleaching Event

Heat stress is causing the Great Barrier Reef to endure its third mass bleaching event in five years, scientists said Thursday, another sign underscoring the urgent need to tackle the climate crisis.

The grim--but expected--assessment of the health of the world's largest coral system, based on aerial surveys, was released by the Great Barrier Reef Marine Park Authority. The Australian agency detected "very widespread bleaching," referring to the phenomenon when stressors cause coral to expel algae, its main food source, and turn white, putting them at risk of death.

"The reef had only just begun recovering from impacts in 2016 and 2017 and now we have a third event," the marine park's chief scientist, David Wachenfeld, told the BBC.

Terry Hughes, director of the Australian Research Council's Centre of Excellence for Coral Reef Studies at James Cook University in Australia, decribed the coral damage he viewed as "heartbreaking." Hughes drew attention to the coral damage he saw in a brief but emotional account on Twitter Thursday:

Among the findings listed in the authority's new statement were that the surveys "mostly confirm[ed] the worst bleaching is on reefs that suffered the highest heat stress this summer, which extended across large areas of the reef."

Researchers also detected "a wide variety of bleaching severity--ranging from no bleaching to the most severe category. Some southern areas of the reef that had little or no bleaching in 2016 and 2017 have now experienced moderate or severe bleaching."

The main culprit for the damage was clear. "Climate change remains the single greatest challenge to the reef," said the agency.

Yet the Australian government continues to back fossli fuels--and is trying to exploit the coronavirus crisis to further push coal development.

Leading environmental group Greenpeace said the latest reef assessment is more evidence the government must change its approach to energy.

"Coal-driven climate change is threatening our beautiful reef, and the many communities and tourism workers who depend on a healthy reef for their livelihoods which are already at risk from the coronavirus outbreak," said Kate Smolski, acting program director of Greenpeace Australia Pacific.

"In order to protect the Great Barrier Reef," she continued, "we need real solutions to address the climate crisis which is being driven by the burning of coal, oil and gas."

"Greenpeace is calling on Prime Minister Scott Morrison to take climate change seriously, get out of bed with the fossil fuel industry, and protect the Great Barrier Reef by urgently reducing Australia's greenhouse gas emissions, which have been rising for over four years," said Smolski.