Climate crisis is greatest threat to Australia’s future and security, former defence leaders warn

The climate crisis is the greatest threat to the future and security of Australians and the country is unprepared for its increasingly harsh impacts, a group of defence leaders has warned.

In a statement, to be published in a full-page advertisement in The Australian newspaper on Wednesday, senior retired defence and security personnel have called on political leaders to make the security risks posed by climate change a central issue of the forthcoming federal election.

"As ex-service members and experienced security practitioners who have witnessed up-close the devastation of war and crisis, we consider that climate change now represents the greatest threat to the future and security of Australians," the letter says.

"The first duty of government is the safety and protection of the people, but Australia has failed when it comes to climate change threats. Australia currently has no credible climate policy, leaving our nation unprepared for increasingly harsh impacts.

"We call upon all those offering themselves as political leaders in this election year to make climate change a primary focus and commit to mobilising the resources necessary to address this clear and present danger."

The statement has been issued by the Australian Security Leaders Climate Group (ASLCG) and signed by 17 senior former defence and security personnel including former defence force chief Admiral Chris Barrie and former deputy chief of the Royal Australian Air Force Air Vice-Marshal John Blackburn.

Its publication comes a week after Barrie told a conference defence personnel are not allowed to speak out on the national strategic threats posed by climate change without prior approval from the defence minister Peter Dutton's office.

Dutton's office rejected those remarks as incorrect.

Barrie said climate change had previously contributed to concurrent wheat crop failures in Ukraine, Russia, China and Australia, which led to rising food prices in countries around the world and became a key trigger for the Arab Spring and regional instability.

"Now high energy and food prices triggered by the Ukraine invasion could contribute to social unrest in countries as far apart as Egypt and Indonesia, which is right on Australia's doorstep," he said.

Barrie said climate change would only make these occurrences more frequent and, without urgent action by political leaders, "we can expect to see increasing instability, conflict and forced migration from neighbouring nations and within our region".

The letter states that global heating imperils the health, well-being and livelihoods of Australia's people and that hotter and more extreme weather, floods, fires and cyclones are threatening water, transport, food and other critical infrastructure systems, disrupting supply chains and undermining our Australia's resilience.

The defence leaders write that the defence force, including reserves, is being increasingly called upon to undertake climate-related humanitarian and disaster relief, such as during the black summer bushfires, and that across the region climate change was an "existential threat to nations and communities".

They said climate should be an immediate security priority and "at the top of the national agenda".

"While our allies are taking action, climate-security risks are not being properly assessed in Australia; we are ill-prepared, and failing in our responsibilities as a global citizen and strategic defence ally," the letter states.