On Thursday, the Great Barrier Reef Marine Park Authority said its latest aerial surveys had shown that the severity of bleaching varied across the reef. 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.
Miller has recently returned from assessing an area off Cooktown, with the council saying the evidence has been backed up by renowned scientist Terry Hughes, who is conducting aerial surveys this week over hundreds of individual reefs.
The Great Barrier Reef extends over an area of more than 344,000 square kilometers, exceeding the size of Italy.
According to reports, the warmer sea temperatures, especially in February, have apparently caused huge coral loss across the world's largest reef system.More news: Katrina Kaif stole my idea: Deepika Padukone takes a jab
However, they have also found a few healthy pockets amid the reef, which covers over 2,300km (1,400 miles).
Australia's Great Barrier Reef is a prime example, having already suffered back-to-back severe mass bleaching events in the past five years. Some parts of the southern reef that escaped the bleaching of 2016 and 2017 have experienced moderate or severe bleaching.
It follows the worst outbreaks of mass bleaching on record killing about half the shallow water corals on the world's biggest reef system in 2016 and 2017.
The researchers expect this year's event to drive a high coral mortality rate on the severely bleached sections of the reef. "Climate change remains the single greatest challenge to the reef", said the agency.More news: Valve confirms Half-Life: Alyx, its 'flagship VR game'
Environmentalists have criticised Australia's conservative government for favouring an expansion of the country's massive coal mining industry over action to curb climate change. In august, the Great Barrier reef's outlook for the first time described as "very poor".
Earlier this month, David Wachenfeld, chief scientist at the Great Barrier Reef Marine Park Authority, said ocean temperatures over the next month will be crucial to how the reef recovers from heat-induced bleaching.
The Great Barrier Reef Marine Park Authority past year downgraded its outlook for the corals' condition from "poor" to "very poor" due to warming oceans.More news: Fed chair Jerome Powell says 'we may well be in a recession'