The Great Barrier Reef should be placed on to a list of world heritage sites that are “in danger”, according to a recommendation from UN officials that urges Australia to take “accelerated action at all possible levels” on climate change. The United Nations Educational, Scientific and Cultural Organization says the world’s biggest coral reef system should be placed on the list at the world heritage committee meeting next month. The recommendation has sparked a flurry of activity from the Australian government, with the environment minister, Sussan Ley, saying she had already joined the foreign affairs minister, Marise Payne, in a call to Unesco’s director general, Audrey Azoulay. If the committee followed the recommendation, experts said it would be the first time a natural world heritage site has been placed on the “in danger” list mainly because of impacts from the climate crisis. Global heating caused by fossil fuel burning has driven ocean temperatures higher, leading to three mass bleaching events on the 2,300km reef since the last time it was assessed by the committee in 2015. Ley said the government would “strongly oppose” the recommendation, claiming officials had been “stunned” by what she described as a “backflip on previous assurances” by UN officials the step would not be taken. World heritage sites are global icons and “in danger” listings are usually recommended after effects from armed conflict and war, pollution, poaching and uncontrolled urbanisation. The Unesco report says a revision of Australia’s key reef policy – the reef 2050 plan – should “fully incorporate” conclusions from a major government review that “accelerated action at all possible levels is required to address the threat from climate change”. The report said despite efforts and achievements by the state and federal governments, key targets on improving water quality had not been met. “The plan requires stronger and clearer commitments, in particular towards urgently countering the effects of climate change, but also towards accelerating water quality improvement and land management measures,” it said. Ley said she had called Azoulay overnight, saying: “I made it clear that we will contest this flawed approach, one that has been taken without adequate consultation. “This sends a poor signal to those nations who are not making the investments in reef protection that we are making.” She said climate change was the biggest threat to the reef but the world heritage committee was “not the forum” to “make a point” about climate change. “Operational guidelines” for the listing had not been followed, she said. The guidelines do allow for an “in danger” listing due to climate impacts. The last time the reef faced the threat of an “in danger” listing, the government embarked on a mass lobbying effort to pressure the 21-country committee. Unesco is also recommending that a monitoring mission be launched to develop “corrective measures”, asking the Queensland and federal governments to submit a report by February 2022 outlining new steps to protect the reef. The conservation groups WWF-Australia and the Australian Marine Conservation Society have lobbied members of the committee before the reef decision, asking them to pressure Australia to take stronger action on cutting greenhouse gas emissions. A consultant to the AMCS, Imogen Zethoven, said Australia’s climate policies were “more consistent with a 2.5-3.0C rise in global average temperature – a level that would destroy the Great Barrier Reef and all the world’s coral reefs.” She said the Australian government’s inaction had led the reef to the brink of the “in danger” listing. Richard Leck, head of oceans at WWF-Australia, said Australians would be shocked by the Unesco recommendation but it was “a powerful message” that the government needed to “lift its game” on climate change. Australia’s greenhouse gas emissions targets have not changed since 2015 and the prime minister, Scott Morrison, has resisted international pressure to adopt a firm net zero target by 2050. Assoc Prof Scott Heron, of James Cook University, has led a study on the effects of climate change on world heritage reef sites. He said the recommendation was a “surprise” but “also not completely unexpected.” “These cards have been stacking up over the past years,” he said.