‘Uncharted territory’: Great Barrier Reef report piles pressure on Labor’s climate target

The panel forecast that if the rest of the world acts consistently with Labor’s target, global warming would hit 2 degrees and lead to the degradation of 99 per cent of the world’s coral reefs.

The Australian institute’s monitoring team leader Mike Emslie said climate change was driving increasingly frequent and longer-lasting marine heatwaves.

“The peak of the most recent bleaching event in March occurred when the accumulated heat stress caused widespread bleaching but not extensive mortality,” he said.

“The increasing frequency of warming ocean temperatures and the extent of mass bleaching events highlights the critical threat climate change poses to all reefs, particularly while crown-of-thorns starfish outbreaks and tropical cyclones are also occurring.”

While the institute has recorded the highest levels of coral cover in the southern reef since surveys began 36 years ago, Emslie said any gains could be reversed “in a short amount of time”.

That’s because the recent flush of coral growth was dominated by fast-growing acropora species that are particularly vulnerable to damage from bleaching caused by heatwaves and wave damage from cyclones.

“These corals are particularly vulnerable to wave damage, like that generated by strong winds and tropical cyclones,” he said.

World Wide Fund for Nature head of oceans Richard Leck said nations must “do everything possible” to halt warming at 1.5 degrees.

“Australia can do its part by rapidly driving down its greenhouse gas emissions this decade and become a renewable energy export superpower,” Leck said.

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Environmental adviser Imogen Zethoven was the lead author of a Griffith University study in July that called for the reef to be listed as “in danger”. She argued downgrading its conservation status would create an opportunity for Australia to build ties by working on conservation with its Pacific neighbours who also have vulnerable World Heritage-listed reefs – including Solomon Islands, Indonesia and the Philippines.

“This is about a global policy on climate impacts and risk that could apply to any climate-vulnerableWorld Heritage site,” Zethoven said.

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