Great Barrier Reef bleaching turns up heat in key Coalition seat

The Great Barrier Reef is suffering its second bleaching event in as many years, with the marine park authority reporting corals in distress due to an underwater heatwave stretching 1300 kilometres from Townsville to Cooktown.

Bleaching is a major threat to the health of the reef and its World Heritage status, both of which are key to tourism and the fate of the seat of Leichhardt, held by the Coalition on a tight 3.4 per cent margin by long-serving MP Warren Entsch, who is retiring at this election.

It is the sixth time in 10 years that mass bleaching has hit the 2300 kilometre long jewel in the crown of the world’s coral ecosystems and an interjection in the Leichardt contest, based around Cairns, where paramedic Jeremy Neal is running for the Coalition against former professional basketballer and Labor candidate Matt Smith.

The candidates vying to replace Entsch claim they have the right plan to safeguard the reef’s health, while their parties clash over climate science. Neal said his party embraced “practical solutions” while Labor was “all talk”.

“Emissions have flatlined, despite their [Labor’s] big promises, and they’re not on track to meet any of their own targets.

“The Coalition is committed to net zero by 2050, with a plan to get us there, and unlike Labor, we’re focused on practical solutions that can actually deliver.”

But Smith said climate change posed an imminent risk to the reef and argued that only Labor had fully embraced the climate science.

“Labor put the reef front and centre in resilience and world-class science and management,” Smith said. “A [Peter] Dutton-led LNP government is a real threat to the ongoing protection of the Great Barrier Reef and the 64,000 jobs that it supports.”

Coral bleaching threat level from March to April 2025, with brown the most severe and purple the least. Credit: National Oceanic and Atmospheric Administration.

Mass coral bleaching has occurred on the Great Barrier Reef in 1998, 2002, 2016, 2017, 2020, 2022, 2024 and now 2025.

Scientists have found global warming is driving up the frequency and severity of bleaching. Australia’s climate has already warmed by an average of 1.47 degrees over the past century, according to the Bureau of Meteorology. A report by the Australian Academy of Science said if the world warmed by 2 degrees, only 1 per cent of corals would survive.

Prime Minister Anthony Albanese declared his belief in climate science in the second leader’s debate on Tuesday night. “The science is very clear. Doesn’t mean that every single weather event is because of climate change. It does mean that the science told us that the events would be more extreme and they’d be more frequent,” Albanese said.

Dutton said the consequences of climate change were visible but ducked a question on whether it was making natural disasters worse, saying he would “leave it up to scientists to provide advice”. “The question is what we can do about it as a population of 27 million people,” Dutton said. “But at the moment, China is building two coal-fired power stations a week.”

Coral bleaching is caused by marine heatwaves – a phenomenon in which the organisms switch from their iridescent colours to ghostly white, signalling they are sick and struggling to cope with high temperatures.

Bleaching does not necessarily mean corals will die, but repeated and more frequent stress increases the risk of mortality.

Experts including the Australian Institute of Marine Science have found repeated mass bleaching is an extreme stress on the reef ecosystem. While corals can bounce back rapidly, the regrowth is dominated by a narrow range of coral species, which means the colourful diversity of the reef is being lost.

Coalition environment spokesman Jonathan Duniam said bleaching was “very concerning” but pointed to the regrowth seen on the reef.

“It must be remembered that coral can and does survive bleaching events. During our years in government, the amount of hard coral cover across the reef reached the highest levels ever recorded.”

Federal Environment Minister Tanya Plibersek claimed the reef’s health would suffer under a Coalition government.

“Labor will protect nature, fund essential science, invest in threatened species, and act on climate change,” she said.

World Wildlife Fund Australia oceans campaigner Richard Leck said the next term of government would be critical to protecting the health of the reef and its World Heritage status from coral bleaching, which had transformed from a rarity to normal.

“Year after year the reef is being cooked by underwater heatwaves,” Leck said. “It’s our international treasure and it desperately needs serious action to drive down emissions.”

Australian Marine Conservation Society campaigner Simon Miller echoed his remarks. “The window for action is rapidly closing,” Miller said.

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