The most powerful bureaucrats in Australia have been wargaming to prepare the country for "national-scale systemic climate risks" that could impact "the full spectrum of human activity" and are already "overwhelming" the country's ability to respond.

Key points: The Secretaries Group on Climate Risk includes some of the country's most senior military figures and the heads of the Federal Government's biggest departments

The Secretaries Group on Climate Risk includes some of the country's most senior military figures and the heads of the Federal Government's biggest departments The minutes from the group's meetings noted extreme weather was already "overwhelming" the country's ability to respond to climatic events

The minutes from the group's meetings noted extreme weather was already "overwhelming" the country's ability to respond to climatic events The group also considered legal risks that climate change could pose for the Government

The ABC can reveal a group called "the Secretaries Group on Climate Risk" began meeting in March 2017.

It includes some of the country's most senior military figures as well as the heads of the federal government's biggest departments.

The group has not been formally disbanded, but fell into dormancy. But before that, the group warned the government it was widely seen as trailing the private sector in addressing the impacts of climate change.

The group conducted a set of exercises called "Project Climate Ready", in which the government chiefs wargamed future scenarios that it is expected could occur because of climate change.

Got a confidential news tip? Email ABC Investigations at investigations@abc.net.au For more sensitive information: Text message using the Signal phone app +61 436 369 072 No system is 100 per cent secure, but the Signal app uses end-to-end encryption and can protect your identity. Please read the terms and conditions.

Despite the group planning several meetings throughout 2018, it has not met since March of that year.

A meeting planned for July 2018 never occurred, and no meeting has been arranged since, documents obtained by the ABC under Freedom of Information laws show.

A spokesperson for the Department of Environment confirmed there were no plans for another meeting.

The spokesperson said the work of the Secretaries Group was now being done by a more junior deputy secretary-led group, called the "Disaster and Climate Resilience Reference Group".

That group existed prior to the Secretaries Group's first meeting, and was described in the FOI documents as "supporting" and "reporting to" the Secretaries Group's work.

Minutes and agendas for the group's meetings show the seriousness with which the federal bureaucracy treated the threat of climate change during a period when then-prime minister Malcolm Turnbull failed to win support in his own party for an emissions-reduction mechanism in the electricity sector.

In establishing the group, the documents note that climate change "influences the full spectrum of human activity".

The minutes from the meetings noted extreme weather was already "overwhelming" the country's ability to respond to climatic events. As examples, they noted:

The Melbourne asthma storm, in which 10 people died.

The Melbourne asthma storm, in which 10 people died. The South Australian blackout, which resulted in the entire state being plunged into darkness.

The South Australian blackout, which resulted in the entire state being plunged into darkness. The "convergence of floods and bushfires in Tasmania".

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 3 minutes 13 seconds 3 m 13 s Political storm erupts after SA loses power.

Project: Climate Ready

Project Climate Ready was conducted to better understand how to manage the increasing risk of catastrophic events.

It consisted of a series of scenarios jointly developed by the Department of Defence and the Department of Environment and Energy.

The details of the scenarios have been kept secret, with the government refusing to release them to the ABC under Freedom of Information laws.

But in commissioning them, the group said they "could include modelling a spring at 10 degrees (Celsius) above average" and "relate to concurrent extreme weather events, legal liability, national security or health".

They said the exercise would involve planning for the scenario over a period of "15 to 20 years".

The group noted Project Climate Ready should help the government "identify actions and prompt discussion on what decisions need to be taken to build resilience to climate change, by who, and when."

Government warned on litigation risks

In addition to direct physical risks impacting health and national security, the group also considered legal risks that climate change could pose for the government.

To prepare for the meetings, the heads of the departments were given legal advice by Noel Hutley SC outlining how company directors and trustees of superannuation funds who fail to consider climate risks could be sued, as well as news articles about ongoing climate change-related litigation.

Josh Frydenberg was environment minister when the Secretaries Group on Climate Risk began. ( ABC News: Luke Stephenson )

"The intention was to understand what challenges could be presented by such events, in order to inform policy and program design and thinking," a spokesperson for the environment department said.

"Scenarios explored some of the possible impacts of extreme weather events in a number of sectors including health, infrastructure and energy."

In a brief to the then-environment minister Josh Frydenberg in 2017, outlining what the group had found, the secretary of the department of environment said "there is a broad-based perception that the public sector is behind private-sector practice".

"Many private-sector companies, including resource companies … are well advanced in their management of climate risk," the brief said.

"Public sector agencies own and manage large assets, employ staff in locations and provide or support services that are at risk of extreme weather events, which are becoming greater because of climate change."

The ABC contacted the offices of Environment Minister Sussan Ley, as well as former environment minister and now Treasurer Josh Frydenberg.

Minister for Drought and Natural Disasters David Littleproud, who has said he "[doesn't] know if climate change is manmade", was also asked to comment.

A spokesperson for the Department of Environment said the work of the Secretaries Group was being progressed by the deputy secretary group.

"For example, during 2018-19 the Group discussed development of the recently released National Disaster Risk Reduction Framework.

"The Group also supported development of Climate Compass, which is a framework for climate risk management for Commonwealth agencies developed by CSIRO and the Department of the Environment and Energy," the spokesperson said.

Australia 'probably more prone to disasters'

Professor Andy Pitman says climate change needs to be taken seriously because the consequences "are here now". ( Supplied: Twitter )

Professor Andy Pitman, head of the Australian Research Council Centre of Excellence for Climate Extremes, said wargaming future scenarios was exactly what the public service should be doing.

"Climate change is really, in the context of the government, simply a risk. And risks should always be thoroughly examined," Professor Pitman said.

"The consequences of climate change are here now and are not something to be thought of as just in the future. But obviously with the emissions trajectories as they are it's inevitable that risks will continue."

He said he was not particularly worried whether this group or some other group was carrying on that work.

"What would concern me is if the scenario-planning — the stress-testing — isn't being done in government."

Former deputy commissioner of the NSW Fire Brigade Ken Thompson is more concerned.

"It does worry me because there's a lot of work that needs to be done in this space," Mr Thompson said.

"The problem with Australia is that we're probably more prone to these disasters than many other countries but we're probably one of the least-prepared simply because we don't have this overarching government framework that's needed to help us plan," he said.

Dr Sarah Boulter, a senior researcher at the National Climate Change Adaptation Research Facility, said a high-level group needs to be looking at climate risk at a whole-of government level.

She said both the impacts of climate change — and potential adaptations — have consequences that cut across government departments.

"So if one department says, 'look, the only way that we can protect this part of the coast is to build a seawall' — that will have implications for biodiversity, for fisheries, for transport."