What is coral bleaching?
Mass coral bleaching events have occurred on the Great Barrier Reef in 1998, 2002, 2016, 2017, 2020, 2022 and now 2024.
Coral bleaching occurs when the organisms are under severe stress due to abnormally high water temperatures. Recovery is possible if sea surface temperatures return to normal quickly enough.
Bleaching causes corals to expel the algae living in their tissues and turn white. Scientists say global warming is the major factor driving more frequent bleaching events.
The authority will now conduct in-water surveys to assess the extent of coral deaths from the bleaching event, and to determine to what depth corals have been affected.
The aerial survey covered more than 300 inshore, mid-shelf and offshore reefs, from Cape Melville north of Cooktown to Bundaberg in the south.
The current underwater heatwave is most intense on the southern Great Barrier Reef. Since 2016, this area has largely escaped the severe impacts caused by bleaching, as previous events have occurred further north.
World Wildlife Fund Australia said it was alarming that this bleaching event was most intense at the southern end of the reef, where corals had not suffered extreme marine heatwaves before.
“Unless we see a significant drop-off in temperatures in the next few weeks, the risk of significant coral mortality is high,” said WWF Australia’s head of oceans Richard Leck.
Australia’s climate has already warmed by an average of 1.47 degrees over the past century.
A report by the Australian Academy of Science said if the world warmed by 2 degrees, only 1 per cent of corals would survive.
Loading
The Queensland government recently committed to a more ambitious climate target, to cut emissions by 75 per cent by 2035. However, the federal government’s target to cut national emissions 43 per cent by 2030 and reach net zero by 2050 is consistent with international efforts that would lead to 2 degrees or more of warming.
Australian Marine Conservation Society campaign manager Dr Lissa Schindler said governments must ramp up emissions reduction to save coral reefs.
“This is a huge wake-up call for Australia and the global community that we need to do much more to address climate change, which is driving the marine heatwaves that lead to coral bleaching,” Schindler said.
Environment Minister Tanya Plibersek said the federal government had boosted Australia’s climate target since its 2023 election win and was committed to boosting reef health.
“We need to act on climate change. We need to protect our special places and the plants and animals that call them home,” Plibersek said.
“We’re investing a record $1.2 billion in the reef, including to ensure we have the best science on reef adaptation and resilience. We’re funding projects that improve the reef’s ability to recover after a bleaching event, like improving the quality of water flowing onto the reef, eradicating feral and invasive species and removing marine debris.”
With Reuters
Source Agencies
