The Great Barrier Reef Marine Park Authority (GBRMPA) and the Australian Institute of Marine Sciences (AIMS) said on Friday that aerial photography of about 750 reefs shows widespread reef bleaching, with the most severe bleaching occurring in northern and central areas.
“More than half of the living coral cover that we can see from the air is highly bleached, completely white and may show signs of pink, yellow and blue fluorescence,” said AIMS coral biologist Neil Cantin.
“Corals produce these fluorescent pigments in an attempt to protect their tissues from the heat and intense sun during these marine heatwaves.”
This is the fourth mass bleaching event in six years and the first since 2020 that about a quarter of the reefs surveyed showed signs of severe bleaching. This event came just three years after successive bleaching events in 2016 and 2017. Previous bleaching events occurred in 1998 and 2002.
David Wachenfeld, Chief Scientist at GBRMPA, said the corals were stressed but did not die.
“If the water temperature drops, bleached corals can recover from this stress. It is important to remember that we had a massive bleaching event in 2020, but coral mortality was very low,” Wachenfeld said.
Natural wonder under threat
Australia’s Great Barrier Reef stretches 1,400 miles (2,300 kilometers) along the coast of Queensland. Before the pandemic forced the closure of the borders, it attracted about three million tourists annually.
This year, aerial photography from helicopters and planes showed that the greatest bleaching occurred near Townsville. Tourist areas near Cairns and Port Douglas were less affected due to lower levels of heat stress.
Bleaching occurs when a stressed coral sheds algae from its tissue, depriving it of its food source. If conditions do not improve, corals may starve to death and turn white when their carbonate skeleton is exposed.
“Even the toughest corals take nearly a decade to recover,” says Jody Rummer, assistant professor of marine biology at James Cook University in Townsville.
“So we are really losing that recovery window. We are facing bleaching events, heatwaves. And the corals just don’t adapt to these new conditions,” she said. .
The Australian government is under pressure from UNESCO to prove it is doing enough to save the reef.
Earlier this year, the Australian government pledged A$1 billion ($700 million) over 10 years to support new climate change adaptation technologies, invest in water quality programs and protect key reef species.
While the additional funding was welcomed, global climate experts called on the government, in part, for not doing enough to move Australia away from fossil fuels.
Tracking climate action gives the country a “gross under-rating” for its climate action. “The government appears to be intent on replacing fossil fuels with fossil fuels,” the report said, referring to the government’s “recovery with gas” program announced in 2020 to bring the country out of the Covid-19-related economic downturn.
He said countries and private companies investing in coal are costing the world at the expense of the climate. And he said the money spent on fossil fuels and subsidies was “a stupid investment that resulted in billions of stranded assets.”
“The time has come to end fossil fuel subsidies and stop the expansion of oil and gas exploration,” he said.
Amanda McKenzie, CEO of the Climate Council, said the real issue the government needs to address is climate change.
“In order to give our reef a chance to win, we must solve problem number one: climate change. No funding will stop these bleaching events unless we reduce our emissions this decade,” she said in a statement.