Climate change is presenting Australia’s Defence Department with new challenges on the domestic front. One of the more pressing is the need to safeguard defence installations across Australia as climate-driven natural disaster events become increasingly frequent and extreme.

This increasing severity of natural disasters, such as last summer’s bushfires, means that Defence will continue to be required to step up as a national disaster response force.

A framework for climate preparedness needs to be developed at all levels of Defence planning, especially in procurement procedures.

Defence has some policies and guidance in place for environmental management at its facilities, such as its Smart infrastructure handbook; however, it hasn’t yet developed a comprehensive long-term plan to manage environmental change.

The defence presence in the Northern Territory illustrates the range of issues that the organisation will need to focus on in the next decade and beyond. All defence activities, from basing to space programs, will be affected by extreme weather events.

Royal Australian Air Force Base Tindal, located close to the township of Katherine, has already had experience with such events. In 1998, one of the worst floods in the Northern Territory displaced nearly the entire population of Katherine. More than 5,000 residents were forced out of their homes in little over 24 hours. In the 22 years since that disaster, flooding has been a persistent issue for the town, which must remain on alert to deal with the threat of unexpected flooding.

The Tindal base recently received more than $1 billion to upgrade its facilities, including a large, flat area of concrete and bitumen and a 2.7-kilometre asphalt runway. The majority of funds ($737 million) will be allocated to extending the runway and creating new fuel storage facilities to improve accessibility for US Air Force aircraft.

Locals and environmental experts are concerned that run-off from the broad expanses of concrete and bitumen on the base will mean more overflow into Tindal Creek, which is the key source of floodwater in Katherine. The upgrades at Tindal will significantly increase the risk of flooding in the township.

If the expanded runways and tarmac exacerbate flood conditions, it won’t just affect the people of Katherine, but will also put millions of dollars of onsite defence assets at risk. It also could contribute to chemical contamination of groundwater in the area.

Getting this sort of work wrong can be hugely expensive and has the potential to damage Defence’s reputation in the communities in which it operates. Defence has already been in federal court over per-and poly-fluoroalkyl substances (PFAS) contamination of local groundwater, and agreed to settle a class action by Katherine residents for $92.5 million in March.

Earlier this year, the proposed redevelopment of RAAF Base Tindal was examined by the Parliamentary Standing Committee on Public Works, which recommended that the project be approved. In its original statement of evidence to the committee, Defence said that it would put measures in place to deal with the environmental impacts of the upgrade, including flooding and PFAS contamination.

These measures would extend existing water retention measures to the new facilities, such as the stormwater network in and around the airfield, built to divert run-off and reduce the extent of flooding. But nowhere in this document is there an acknowledgement of the greater risks to facilities posed in an era of climate change. Existing measures may not be enough.

This raises the broader question about Defence’s role and responsibility in protecting the environment and local communities in this new era. As a Commonwealth agency, Defence has obligations under the Environment Protection and Biodiversity Conservation Act 1999 to ensure that its activities do not have a significant adverse impact on the environment. This is supported by policies in the department’s Environment and heritage manual. But both the EPBC Act and Defence’s environmental policies will likely need to be updated to cope with the realities of climate change.

These issues will be complicated by expectation, noted in the government’s 2020 defence strategic update, that the Australian Defence Force will need to be ready to deploy to assist communities to deal with extreme weather events. But it’s unclear how Defence will resource and manage this new dimension of its mission.

The nature of public security in Australia is changing, and our institutions must be ready to change with it.