Bleaching occurs when heat-stressed corals expel the algae that gives them life and colour.It is the fifth time in eight years widespread damage has been detected at the Unesco World Heritage site.Only two mass bleaching events had been recorded until 2016, and scientists say urgent climate action is needed for the reef to survive.
“The frequency and scale at which these mass bleaching events are now occurring is frightening – every summer we’re holding our breath,” said Greenpeace Australia’s David Ritter.
“Claims that Australia is taking the health of the Great Barrier Reef seriously ring hollow when we continue to expand and subsidise the coal and gas industry to the tune of billions every year.”
“It’s literally cooking the Reef,” the Climate Council’s Simon Bradshaw added.
Stretching over 2,300km (1,400 miles) off Australia’s north-east coast, the Great Barrier Reef is the world’s largest coral system and one of its most biodiverse habitats.
An aerial survey of 320 reefs – from the tip of Australia to the city of Bundaberg – showed most are experiencing prevalent bleaching, after a summer of heightened sea temperatures.
The Great Barrier Reef Marine Park Authority said in-water examinations are underway to determine the severity and depth of the damage – which likely varies greatly across the reef.
The body’s Chief Scientist Roger Beeden told the BBC that bleaching in the southern zone though, was the worst in almost 20 years, and could become “unprecedented”.
