and is reshaping Australia's Indo-Pacific security posture
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The Australian Defence Force stands at an unprecedented inflection point.
Climate change is simultaneously stressing its equipment, exhausting its people, and reshaping the geopolitical environment it exists to manage.
What began as a humanitarian footnote in strategic planning has become a structural challenge to Australia's core defence mission.
The evidence accumulated since 2019 demands accounting. Repeated domestic disaster deployments have consumed training time, maintenance budgets, and personnel capacity.
The Indo-Pacific's strategic geometry is simultaneously being redrawn by rising seas, extreme heat, and intensifying geopolitical competition.
Australia's 2023 Defence Strategic Review was the most candid official acknowledgement that climate change had entered the hard security domain.
It confirmed that climate events were already measurably damaging the ADF's capacity to defend Australia.
What remains inadequately answered is whether the institutional response will match the scale of the threat.
Climate change has fundamentally altered the operational tempo of the Australian Defence Force. Catastrophic bushfires, recurring floods, and intensifying cyclones have repeatedly diverted military assets from combat preparation.
The 2023 Defence Strategic Review found this pattern has damaged force preparedness, readiness, and combat effectiveness.[1]
A Department of Defence submission to a parliamentary inquiry revealed a defining statistic. More than 35,100 ADF personnel have participated in domestic relief operations since 2019.[2]
That figure exceeds half the ADF's permanent workforce of approximately 62,000 people. The scale of repeated deployment has placed untenable pressure on training cycles and asset availability. Concurrent disaster activations compound the strain on logistics, maintenance, and personnel scheduling.[3]
Operation Bushfire Assist in 2019-20 marked a structural inflection point in civilian expectations of the ADF. The Black Summer fires triggered the largest domestic military activation in ADF peacetime history.[4]
Successive Operation Flood Assist deployments followed across Queensland, New South Wales, and Victoria in 2021, 2022, and 2024. Army engineers, helicopter crews, and transport units absorbed months of disaster response work in each activation. Training schedules were repeatedly cancelled or curtailed to meet civilian support requirements.
The 2023 DSR directed that Defence must serve as last resort only for domestic civil emergencies.[1]
The Albanese government subsequently established the National Emergency Management Agency to lead disaster coordination. This transfer of primary responsibility aims to protect ADF readiness for its core defence mission. Building civilian capacity sufficient to replace ADF domestic roles will require years of sustained investment.[11]
Climate change has accelerated geopolitical competition across Australia's immediate strategic neighbourhood. Rising seas threaten the existence of low-lying Pacific island states, generating conditions for instability and forced displacement. Every major climate event in the region multiplies demands on Australian diplomatic and military resources.
Tuvalu, Kiribati, and the Marshall Islands face an acute existential threat from sea-level rise. NASA projections indicate these nations will experience at least 15 centimetres of sea-level rise within three decades.[9]
Across Kiribati, the Marshall Islands, and Tuvalu, 95 per cent of all infrastructure sits below 10 metres elevation.[9]
China has exploited this climate vulnerability through targeted aid diplomacy across the Pacific. Nauru severed recognition of Taiwan in January 2024 after China reportedly committed US$100 million in financial aid.[10]
Solomon Islands and Kiribati made similar switches in 2019. China committed approximately US$500 million to the Solomon Islands following recognition of Beijing.[10]
Australia remains the Pacific's largest aid donor, providing approximately 40 per cent of total external assistance to Pacific island countries.[10]
The 2023 DSR identified climate change as a driver of peacekeeping demands, civil unrest, and interstate conflict in Australia's region. This framing elevates climate risk from a humanitarian concern to a core operational planning requirement. The ADF's future regional posture must balance hard-security preparation against escalating disaster assistance demands.[11]
Climate change is imposing measurable physical stress on ADF equipment and installations. Rising temperatures, increased humidity, and intensifying storm events degrade material performance and maintenance intervals. Northern Australian bases, already operating in some of Australia's harshest environments, face the sharpest projected changes.
Darwin is a critical strategic case. Modelling indicates Darwin could experience between 66 and 129 additional days above 35°C annually by 2050. This range depends on whether global warming reaches 2°C or 4°C.[5]
Extreme heat affects aircraft performance thresholds, munitions storage stability, and safe working limits for ground crews. The F-35A Joint Strike Fighter, central to RAAF combat capability, operates within manufacturer-specified thermal limits. As ambient temperatures rise, available flying days within those limits will decrease across northern bases.
Former Chief of the Defence Force Admiral Chris Barrie has warned that some ADF bases risk becoming uninhabitable. Coastal installations including HMAS Cairns and RAAF Base Darwin face compounding risks from sea-level rise and intensifying cyclonic storm surge.[12]
Australia imports approximately 91 per cent of its refined fuel needs from overseas, creating a critical vulnerability in ADF logistics.[7]
The 2023 DSR identified domestic fuel supply chains as a strategic vulnerability requiring urgent remediation. Extreme weather events have demonstrated their capacity to sever road and rail corridors used for fuel distribution to military installations. The government committed to establishing a whole-of-government fuel council to address this risk.[7]
Military equipment operating in humid tropical environments faces accelerating corrosion and material degradation. Increased maintenance intervals for naval vessels and helicopters operating in northern waters add pressure to already constrained budgets. Quantifying these climate-linked cost increases across the full ADF fleet remains a critical gap in public accountability.
Rising temperatures pose an escalating physiological threat to ADF personnel deployed across northern Australia. The wet-bulb globe temperature (WBGT) metric captures combined heat and humidity stress and governs military training protocols. WBGT thresholds are projected to be breached more frequently at northern bases as the climate warms.[5]
Australian Army Research Centre modelling projects significant increases in days when wet-bulb temperatures exceed 30°C at northern military locations.[5]
At 30°C wet-bulb, full combat exertion becomes physiologically dangerous without enforced rest and hydration protocols. This threshold constrains loaded marches, amphibious landings, and all high-intensity training activities. The ADF's northern basing strategy is therefore vulnerable to climate-linked reduction in available safe training hours.
Loaded marches under moderate WBGT conditions have been shown to produce heat casualties among fit, trained soldiers. The risk intensifies sharply once wet-bulb temperature exceeds military policy limits. This threshold will be breached more frequently at northern Australian bases as the climate continues to warm.[5]
Exercise Talisman Sabre, the largest biennial ADF-United States military exercise, operates across Darwin, Rockhampton, and Shoalwater Bay in July. All three locations present extreme heat and humidity that will intensify as global temperatures rise. Warming climates are also expanding the range of tropical vector-borne diseases relevant to ADF medical doctrine and personnel health.[12]
The ADF's permanent workforce stood at 61,189 as of July 2025, against a government target of 69,000 by the 2030s. In 2024-25, more than 75,000 applied but only 7,059 enlisted, limited by stringent standards and long processing times.[15]
Concurrent climate demands on the force compound the difficulty of building the sustained workforce the National Defence Strategy requires.
The ADF consumed approximately 310 megalitres of fuel in 2020-21, establishing it as a major fossil fuel importer. Air Force aviation fuel accounted for 215 megalitres, more than six per cent of Australia's entire aviation turbine fuel market.[8]
Australia imports 91 per cent of its refined fuel needs, linking ADF operational capability directly to foreign supply chains.[7]
In October 2024, the Department of Defence released its Net Zero Strategy and Future Energy Strategy. Both commit Defence to a 43 per cent emissions reduction by 2030 and net zero by 2050.[6]
The Future Energy Strategy named sustainable aviation fuel (SAF) and renewable diesel as the primary near-term pathway for ADF decarbonisation. SAF can reduce lifecycle emissions by up to 80 per cent compared to conventional jet fuel.[7]
SAF and renewable diesel are classified as drop-in fuels, requiring no modifications to existing aircraft, ship, or vehicle fuel systems. This characteristic makes them the lowest-risk near-term option for ADF fleet decarbonisation.[14]
Australia produces zero SAF domestically, creating reliance on fragile global supply chains and fuel priced far above conventional jet fuel.[7]
Developing a domestic SAF production capability would simultaneously address climate commitments and fuel security concerns. Lowy Institute analysis proposes that Defence's demand signal could underpin a domestic SAF industry. Surplus production could then serve commercial aviation during peacetime, giving decarbonisation a security logic beyond environmental compliance.[7]
Climate change is testing the cohesion of Australia's core defence alliances. Divergent rates of adaptation across the AUKUS partnership and Five Eyes network create asymmetries in capability, doctrine, and equipment standards. The ADF must align with allies while managing its own structural climate constraints.
The United States Department of Defense has published its Climate Risk Analysis, identifying climate change as a security threat multiplier. Subsequent shifts in US administration priorities have introduced uncertainty into climate policy alignment across the AUKUS partnership. The ADF must navigate these dynamics while sustaining its commitments under the Defence Net Zero Strategy.[6]
Within the Five Eyes intelligence alliance, climate-related security collaboration is gaining analytical visibility as a distinct priority. The Australian Security Leaders Climate Group has called for a wartime-scale approach to climate defence that includes dedicated intelligence resourcing.[12]
Australia's Tuvalu-Australia Falepili Union Treaty, signed in November 2023, combined climate and security commitments in a landmark bilateral arrangement. Australia committed to support Tuvalu against military aggression, natural disaster, or public health emergencies. The treaty also grants Australia the right to vet potential security agreements Tuvalu considers with other states.[11]
Climate adaptation disparities between the ADF and Pacific island militaries challenge joint humanitarian and disaster relief (HADR) missions. Pacific island forces operate with limited logistical capacity, requiring Australia to assume the lead role in most regional disaster responses.[13]
The ABCA Armies programme standardises military equipment, doctrine, and operational procedures across America, Britain, Canada, and Australia. Embedding climate resilience into ABCA standards for extreme-heat operations will grow in importance as the ADF modernises its fleets. This alignment ensures future Australian hardware acquisitions are tested against the environments in which they will actually operate.
Australia has committed $14 billion to hardening its northern bases for US force rotations under the AUKUS agreement. Climate adaptation must be integrated into this investment programme from the outset, rather than retrofitted later at greater cost. Failure to do so would produce infrastructure that becomes operationally marginal before its planned service life concludes.[12]
Governance of climate risk within the Department of Defence remains inadequately transparent and resourced. The 2023 DSR devoted a dedicated chapter to climate change but withheld many specific judgements in its classified version. This classification limits public scrutiny of the rigour with which climate risk is integrated into Defence planning.[1]
The unclassified DSR acknowledged that its full version contained sensitive material requiring classification. The public document confirmed climate events were damaging ADF readiness but gave limited guidance on mitigation timelines or cost allocations.[1]
The October 2024 Defence Net Zero Strategy and Future Energy Strategy are Defence's most specific public climate governance documents. These outline emissions reduction pathways but provide limited detail on enforcement mechanisms or financial consequences for non-compliance.[6]
The 2024 NDS directed ADF bases to achieve two explicit objectives: climate adaptation and energy resilience. Former Chief of the Defence Force Admiral Chris Barrie has called for a wartime-scale approach to climate defence planning. He has cited ADF training bases at risk of becoming uninhabitable as a concrete planning failure.[12]
Defence procurement remains a critical governance vulnerability. Existing procurement guidelines lack publicly verifiable requirements to test all new hardware operationally above 50°C. The Boxer combat vehicle and F-35A were both designed primarily for temperate European or North American environments.
The 2024 NDS committed to biennial National Defence Strategy updates, providing a mechanism for incorporating evolving climate science. The 2026 NDS was forecast to address whole-of-nation preparedness, including climate risk as a distinct security domain.[12]
Australia lacks a National Security Strategy that would anchor climate risk governance across all agencies beyond Defence alone. ASPI's Climate and Security Policy Centre has argued that climate change will undermine all other security objectives without adequate resourcing. Resolving this governance gap is the central accountability challenge of Australia's climate security posture.[12]
Climate change is reshaping Australian defence capability at every level. From individual soldier readiness to Indo-Pacific strategic geometry, the threat is comprehensive and accelerating. The threat multiplier identified in the 2023 DSR is already degrading force preparedness and enabling geopolitical competitors.
The governance framework remains inadequate to the task. The Net Zero and Future Energy Strategies are welcome steps, yet carry no legally enforceable compliance mechanisms. The most sensitive climate assessments remain classified, limiting public accountability.
Genuine climate resilience within the ADF requires investment across doctrine, medical preparedness, procurement standards, and personnel strategy simultaneously. Incremental adjustment within existing structures will produce incremental failure against an accelerating threat.
The central question Australia faces is whether Defence's climate governance will match the ambition its own strategic reviews have demanded. The 2026 National Defence Strategy provides the next critical accountability test. A comprehensive, publicly accountable, and enforceable climate security framework is the standard any future review must meet.
References
1. Department of Defence, National Defence: Defence Strategic Review 2023 (Commonwealth of Australia, 2023). Australia's most significant recent strategic assessment, publicly confirming that climate events have damaged ADF force preparedness, readiness, and combat effectiveness, and directing the ADF to serve as last resort in domestic disasters.
2. Mahon, R., A Climate Security Priority: Australia's Need for Balanced Domestic Disaster Infrastructure, RSIS Policy Report IP24013 (S. Rajaratnam School of International Studies, 2024). Analyses the Department of Defence submission revealing that more than 35,100 ADF personnel participated in domestic relief operations since 2019, examining the structural risk this poses to military readiness.
3. Clarke, A.G., Military Challenges from Climate Change, Contemporary Issues in Air and Space Power, 1(1) (RAAF Air and Space Power Centre, 2022). Quantifies the increasing trend in ADF emergency first-response taskings using historical open-source data, demonstrating a clear correlation between rising Australian mean temperatures and expanding operational tempo.
4. Center for Climate and Security, MiRCH Update: Key Takeaways from Tracking Climate-Related Military Deployments (Center for Climate and Security, January 2024). Surveys global military climate deployments and documents the 2023 DSR's confirmation that climate events have negatively affected ADF force preparedness, readiness, and combat effectiveness.
5. Australian Army Research Centre, Climate Change and Army Personnel, Australian Army Journal 21(1) (AARC, 2024). Models the impact of rising temperatures on soldier health, training viability, and operational readiness at northern Australian bases, projecting Darwin may experience up to 129 additional days above 35°C annually by 2050.
6. Department of Defence, Defence Net Zero Strategy (Commonwealth of Australia, 2024). Sets out Defence's framework for reducing greenhouse gas emissions by 43 per cent by 2030 and achieving net zero by 2050 within the constraints of military capability, preparedness, and alliance interoperability.
7. Lowy Institute, Finding Opportunity in Australia's Liquid Fuel Security Challenge, The Interpreter (Lowy Institute, 2023). Examines Australia's 91 per cent dependence on imported refined fuel, analyses the strategic convergence between Defence fuel security and sustainable aviation fuel development, and proposes a domestic SAF production model.
8. Cole, B., Decreasing Reliance on Fossil Fuels to Increase Defence Capability, Air and Space Power Blog (RAAF Air and Space Power Centre, 2022). Documents ADF fuel consumption in FY 2020-21 and makes the strategic case for transitioning to sustainable aviation fuels as a means of increasing ADF capability and energy independence.
9. Vu, A. and Nishimoto, N., Pacific Islands Security in the Era of US-China Competition (East-West Center, 2025). Documents the existential climate vulnerability of Pacific island nations including Tuvalu, Kiribati, and the Marshall Islands, and analyses the security implications for Australia and its regional alliances.
10. Freeman Spogli Institute for International Studies, Rising Seas, Rising Stakes: China and Australia Vying for Pacific Hearts in the Climate Crisis (Stanford University, 2025). Analyses China's use of climate-linked aid diplomacy to gain Pacific island diplomatic recognition and measures Australia's role as the region's largest overseas development assistance donor.
11. Center for Security Policy Studies, Perilous to Ignore: The Impacts of Climate Change on Australia's Security (George Mason University, 2024). Provides a comprehensive assessment of climate change as an Australian national security risk, including the DSR's identification of climate as a driver of potential peacekeeping demands and interstate conflict.
12. Desai, I., An Appeal for Climate Action in Australia's Next National Defence Strategy, The Strategist (ASPI, January 2026). Critiques the limited climate ambition in the 2024 National Defence Strategy, documents the $14 billion northern base hardening programme, and references Admiral Chris Barrie's call for wartime-scale climate defence planning.
13. The Cove, The ADF and Australian Disaster Relief in the 2020s and Beyond (Australian Army, 2024). Examines the ADF's dual role in domestic disaster relief and regional stability operations, exploring the capability and doctrine challenges of meeting both simultaneously in a climate-changed Indo-Pacific.
14. Conroy, P. (Minister for Defence Industry), Defence Net Zero Strategy and Future Energy Strategy Released, media release (Department of Defence, October 2024). Announces the complementary Net Zero and Future Energy Strategies, confirming low-carbon liquid fuels including sustainable aviation fuel as drop-in solutions requiring no modification to existing ADF platforms.
15. SBS News, The ADF Has 'Ambitions to Grow' but Can It Fix a 'Terribly Difficult' Geo-Strategic Climate? (SBS, August 2025). Reports on 2024-25 ADF recruitment and retention data including the workforce total of 61,189 as of July 2025, and expert assessment that concurrent domestic climate demands compound workforce challenges.
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