The wet tropics world heritage area in north Queensland has been damaged by climate change in a manner “equivalent” to coral bleaching on the Great Barrier Reef, the area’s management authority has said.

In an extraordinary statement issued on Monday, the authority’s board said the tropical rainforest was in “accelerating decline” and that some of the area’s unique species were at imminent risk of extinction.

Last summer was the hottest on record.

“Extreme heat is the wet tropics world heritage area’s coral-bleaching event equivalent, with some mountain-adapted species, like the lemuroid ringtail possum, unable to survive even a day of temperatures above 29C,” the statement said.

“Mount Bartle Frere recorded an unprecedented 39C at its peak on six days this past summer. The board is convinced that, given the evidence, these key species endemic to the wet tropics world heritage area are under severe and immediate threat from climate change.

“This is occurring now, not in the future, and requires an immediate response.”

The lemuroid ringtail possum is unable to survive above 29C. Experts say it could disappear from north Queensland’s wet tropics world heritage area within three years. Photograph: Alamy

The authority was due to release a climate adaptation plan in June, but says its observations this past summer have added to the urgency.

Reports on the state of the wet tropics have consistently warned about the threat of climate change. In 2016, a report recognised that biodiversity in the area was in decline, with species reducing in population and size, largely due to climate change.

Modelling by the co-author of that report, Steve Williams, based on data collected over 10 years, showed more than half the species endemic to the wet tropics were at risk of extinction before the end of the century.

The authority’s new statement said: “The latest rates of decline suggest that these extinctions are happening even sooner.”

Monitoring has found declines in bird and possum species have continued apace and are “reaching alarming levels”. The authority believes the lemuroid ringtail possum, which is not listed as endangered, could be locally extinct within three years.

In 2017, the International Union on the Conservation of Nature found that climate change threatened to disrupt the fine ecological balance of the area and could result in “rapid and catastrophic” changes.

“These scenarios are increasingly proving true,” the authority said. “While understandably the Great Barrier Reef has received significant funding to address climate change impacts in recent years, investment in terrestrial world heritage areas has not been commensurate with the urgency for mitigating climate impacts on their world heritage values.”

The board has outlined a 10-point plan for action on climate change, which includes local measures and a “call for urgent action on reducing global emissions”.

This past summer was the hottest on record for Queensland’s wet tropics world heritage area. Photograph: Jenny Napier/AAP

The Australian Conservation Foundation said the statement showed climate change was not a “game of costs”.

“While much has rightly been made of the damage climate change is doing to the Great Barrier Reef, we know significant harm is also being done to almost all of Australia’s world heritage sites like Kakadu and Shark Bay,” ACF chief executive Kelly O’Shanassy said.

“Our political leaders must explain how they will protect places like the wet tropics of Queensland by urgently cutting our climate pollution and showing global leadership to encourage other countries to do likewise. And they must explain how they will invest in building the resilience of our natural world so it is in the best condition possible to handle what warming is already in the system.

“This is a clear and urgent call for action from the normally dour public servants and scientists charged with looking after one of Australia’s most precious places.”