In a report published on Thursday, the Australian Security Leaders Climate Group (ASLCG) said the federal government has fundamentally failed to accept the size and immediacy of climate risk, Xinhua news agency reported.

The ASLCG was formed in 2021 by a group of former senior military and security officials, including former Australian Defense Force chief Chris Barrie, who said they were concerned that the security implications of climate change were not being addressed by the government.

In Wednesday's report, they said that the 2024 National Defense Strategy released in April fails to recognise that the rapid acceleration of climate change requires a fundamental recalibration of security and defense thinking.

The report said that the government's commitment of up to 18 billion Australian dollars (11.7 billion US dollars) to upgrade military bases in northern Australia will place many critical bases in areas that are projected to become near-unlivable if global warming reaches 2.7 degrees Celsius above pre-industrial levels.

"Once northern Australia reaches a state of 'near unlivable conditions', the area will be likely to partially depopulate and the services and infrastructure on which civil society and the military depend -- transport and logistics, utilities, health and social and education services for families -- will degrade," it said.

"Already training and operations are being canceled due to extreme heat."

In 2022, the federal government was handed a classified report from the Office of National Intelligence (ONI) on threats posed to Australian security by climate change.

The ASLCG called for a declassified version of the report to be released and for the government to establish a Climate Threat Intelligence branch within the ONI that would regularly provide briefings to parliament.