Scientists say they are fed up with Queensland’s biggest newspaper not covering the worst bleaching event to hit the Great Barrier Reef, so have taken out a full page ad to get the message out.

The ad comes as a survey revealed 93% of the Great Barrier Reef was affected by the bleaching. That finding motivated the Queensland government to call on the federal government to convene an urgent meeting of the nation’s environment ministers to talk about measures to address climate change in light of bleaching.

Organised by the Climate Council, the full page ad in the Courier Mail on Thursday contains an open letter signed by 56 scientists.

“One of the reasons we placed the ad in the Courier Mail was that we’ve seen very little coverage of the coral bleaching event in that paper and in fact there was a front-page story that said the coral bleaching event had been wildly exaggerated,” said Ove Hoegh-Guldberg, director of the Global Change Institute at the University of Queensland and one of the signatories of the letter.

The letter explains that it is the worst bleaching event in its history, and that it is being driven by climate change.

“The Great Barrier Reef is at a crisis point,” the scientists say. “Its future depends on how much and how quickly the world, including Australia, can reduce greenhouse gas emissions and limit ocean warming.”

It then calls for Australia to rapidly phase out coal-fired power stations and for no new coalmines.

“This must be the top priority for Australia if we are to protect what remains of the Great Barrier Reef and other reefs around the world,” they say.

Climate Council member and signatory to the letter Lesley Hughes said: “We are now seeing first-hand the damage that climate change causes, and we have a duty of care to speak out.”

The front page of the Courier Mail. Photograph: News Corp Australia

On 7 February, the Courier Mail ran a story quoting the federal environment minister, Greg Hunt, as saying the reef remained an untouched beauty. His comments were in response to a David Attenborough documentary about the Great Barrier Reef being aired.

“The key point that I had from seeing the first of the three parts is that, clearly, the world’s Great Barrier Reef is still the world’s Great Barrier Reef,” Hunt told the Courier Mail.

The story included a subheading that read: “Reports of reef’s death greatly exaggerated: Attenborough”.

A News Corp Australia spokesman said on Wednesday that the claim there had been very little coverage of coral bleaching in the Courier Mail was “frankly baffling”.

“A quick Google search shows numerous stories have been published including, to highlight just a few, on March 1st, 21st and 30th. And today the paper has covered the issue extensively once again,” he said.

“Equally importantly the paper also exposed Greenpeace’s dishonesty in using deceptive imagery on two separate occasions. Such scare campaigns only serve to undermine the efforts to secure the reef’s future.”

A story about the 93% bleaching appeared in Thursday’s paper on page 13.

The Queensland environment minister, Steven Miles, called for an urgent meeting with Hunt, and said “we have to move quickly on climate change,” and bemoaned the “lack of a coherent effective national policy.”

“The federal environment minister, Greg Hunt, has been downplaying the seriousness of the coral bleaching because he knows the major cause is global warming and we still haven’t seen any meaningful climate change policy from the federal level,” Miles said.

The Queensland government itself has been criticised for approving Adani’s Carmichael mine, which would be Australia’s largest coalmine. Federal approval of the mine will be challenged in court this month, on the basis that emissions released when the coal is burned will threaten the Great Barrier Reef.