The former head of the Great Barrier Reef Marine Park Authority has called for a ban on all new coalmines in Australia, saying the move is needed to protect the Great Barrier Reef from climate change.

“I love the reef and I have worked to preserve it since 1979; I will oppose anything that threatens to destroy it,” said Graeme Kelleher, who was the first chief executive of GBRMPA, a position he held for 16 years. “The Great Barrier Reef is one of the seven wonders of the world.”

Kelleher, who is also a member of the Ocean Elders – a group of global leaders concerned about ocean conservation including Richard Branson, James Cameron, Jane Goodall and EO Wilson – said: “Australia cannot have a healthy Great Barrier Reef and a continuing coal industry.”

Kelleher put his name to a petition started by Greenpeace Australia Pacific, calling on the prime minister, Malcolm Turnbull, to put an immediate ban on all new coalmines.

The Australian government’s deadline for reporting to Unesco’s world heritage committee on its handling of the reef is approaching.

After Australia submits the report Unesco will decide whether or not to again consider listing the Great Barrier Reef on its “list of world heritage in danger”.

The government will need to report on how it has funded and implemented its Reef 2050 long-term sustainability plan, as well as how the recent bleaching event has affected the reef.

Since it last considered including the Great Barrier Reef on its list, the reef has undergone the worst bleaching event in recorded history. According to government agencies, 22% of the reef was killed in one hit, as unusually warm waters bleached and killed the coral.

And that comes at the end of a long-term decline of the reef, Kelleher said.

“Over the last 30 years, the reef has lost 50% of its coral cover and one of the major causes of this is climate change,” Kelleher said.

Kelleher said the continued health of the reef demanded action on climate change and a halt to all new or expanded coalmines.

He said the Adani’s huge Carmichael coalmine must not go ahead and that the high court ought to find in favour of the Australian Conservation Foundation and overturn the federal environmental approval of the mine.

The ACF will argue, on appeal to the high court, that emissions from the burning of coal dug up from the mine will exacerbate climate change and harm the Great Barrier Reef. The government has argued, successfully so far, that there is no link between the mine’s coal and climate change.

“A proper court that, shall I say, was scientifically attuned, would recognise this,” Kelleher said. “Although the coal will not be burned in Australia, it will still be burned in india and that will affect the Great Barrier Reef.”

Greenpeace Australia Pacific reef campaigner Shani Tager said: “Graeme is a giant when it comes to the Great Barrier Reef and has a wealth of experience and knowledge about the threats it faces. His comments are a stark reminder of our need to take serious action to save the reef.”