A group of prominent oceanographers and global leaders has written to Malcolm Turnbull urging him to reject the proposed Adani Carmichael coalmine, which it says will have a devastating impact on the Great Barrier Reef.

The letter from the group Ocean Elders, which includes the renowned marine biologist Dr Sylvia Earle, argues that if it goes ahead the coalmine will damage international efforts to mitigate climate change by increasing global carbon emissions.

The Unesco world heritage committee has released a draft report saying that 75% of the world’s 29 listed coral reefs have been exposed to conditions that cause coral bleaching in the past three years, largely due to climate change.

‘We are in a runaway situation with respect to a warming planet, changing [the] chemistry of the ocean,” Earle said in an interview recorded for RN Breakfast. “We know what to do, it’s a matter of being smart enough, courageous enough, bold enough, sensible enough, to go in this better pathway.”

Earle said the link between the proposed $16bn Adani coalmine and damage to the Great Barrier Reef was “not just speculation,” and said scientific monitoring of the reef showed an “unprecedented decline.”

“I think historically and perhaps even now that people don’t know that their actions in Australia but also globally are altering the resilience, the health of the ocean,” she said. “All of us can do something to turn it around.

“I am not alone being upset about what is happening to the Great Barrier Reef. I know people in Australia who are upset, but this is a world heritage area, a place that is unique and the people who live in Australia have a particular opportunity to take action that can influence something globally, not just now, but far into the future.”

The letter from Ocean Elders was co-signed by Earle; Prince Albert II of Monaco; Sir Richard Branson; Swiss balloonist Dr Bertrand Piccard; prominent oceanographers Dr Walter Munk, Capt Don Walsh, and Jean-Michel Cousteau; former Costa Rican president Jose Maria Figueres; Queen Noor of Jordan; Hawaiian navigator Nainoa Thompson; microbiologist Dr Rita Colwell; CNN founder Ted Turner; and adventurer Sven Lindblad.

It argued that Australia’s responsibility for mining the coal was not abrogated if it was burned in India, as the Indian-owned company Adani intends.

“The 4.7bn tons of carbon dioxide created over the proposed life of the mine from the burning of the coal, whether in Australia, India or any other country, will further contribute to the damaging effects of climate change, including increases in global air and ocean temperatures, increased acidity of oceans, and destruction of coral reefs,” it said.

The letter also suggested that the economic case for federal government support of the mine does not stack up, citing the “decreasing global market for coal.”

Adani is awaiting approval for a $900m taxpayer loan to build a railway from the Abbot Point coal terminal to the Carmichael mine.

The letter urged Australia to “demonstrate climate leadership” by abandoning the project.

It was sent to Turnbull and the Queensland premier, Annastacia Palaszczuk, on 14 June, the day the Senate passed changes to the Native Title Act that would allow the mine to go ahead without unanimous support from traditional owners.

Adani lost majority support from the Wangan and Jagalingou traditional owner group last week, but the native title amendments mean it does not need majority support to broker an Indigenous land use agreement, which is critical to the project securing finance.

On Wednesday Queensland’s environment minister, Steven Miles, issued a statement in response to the the World Heritage Committee draft report on climate change and coral bleaching, calling for “immediate action on a global scale” to protect the future of all coral reefs, particularly the Great Barrier Reef.

“This means that both Australia and Queensland will need to do their fair share,” he said.

It is the second time the Ocean Elders have written to Turnbull, following a letter in April 2016 that urged Australia to phase out coal and “become a renewable energy based nation.”

The organisation was founded in 2010 to further a push by Earle to draw public attention to need for greater conservation and protection of the ocean.