Despite defence spending increasing in several national budgets, climate adaptation within the military is lagging behind.
As the climate crisis accelerates, militaries around the world face dual challenges: maintaining their core mission of ensuring security, while adapting to the changing environment.
But the sector also has to carry out a “war on greenhouse gas emissions”, in the words of Doug Weir, director of the non-profit Conflict and Environment Observatory (CEOBS).
In 2007, the UN Security Council held its first debate on climate change, bringing the topic to the forefront of international security discussions.
“Since then, there has been increased interest in uncovering how climate change will impact the missions and mandates of different countries’ militaries,” Sofia Kabbej, researcher at the French Institute for International and Strategic Affairs (IRIS), tells Euronews Green.
According to CEOBS, however, there has been little scrutiny of the defence sector’s climate impact, and the non-profit estimates it to be responsible for an enormous 5.5 per cent of global emissions annually.
Militaries are now beginning to review their practices, not only to meet climate goals but also to maintain their strategic edge in an evolving geopolitical landscape.
What’s good about greening the military?
The military’s ‘raison d’être’ – its ability to operate anytime, anywhere – remains central to the sector, but there is an increased understanding that readiness would not be compromised by environmental responsibility.
Past defence operations and training have caused significant environmental harm, including marine contamination by chemical warfare agents and pollution from heavy metals such as lead, which poses risks to both personnel and civilians.
Moving forward, militaries could prevent such long-term damage by using techniques to reduce the amount of hazard and waste, and alternative materials that are less polluting.
Streamlining sustainable practices across military activities would also make humanitarian support operations more eco-friendly, as soldiers often assist local communities or act as first responders in crises such as earthquakes or floods.
Defeating fossil fuel emissions
The military sector is one of the world’s largest energy consumers and polluters, heavily reliant on fossil fuels.
Simon Baumann, officer in the Multinational Capability Cooperation Unit at NATO, highlights that, on average, six per cent of countries’ military budgets are on logistics and fuel supply. Cutting fuel dependency could decrease emissions and bring strategic and financial benefits: “There’s a huge economy of scale for us to drive down costs,” he says.
In order to reduce fuel use, nations like the UK are adopting hybrid-electric drive systems for military trucks, patrol and armoured vehicles.
More armies are testing on-site renewable energy production, such as solar or wind power, as well as hydrogen fuel cells in military camps. For air defence, where other energy sources are not yet available at scale, measures to cut emissions are in place too, at a different level.
“We are moving to more synthetic [simulated] training environments, to reduce costs and emissions,” says Shaun Harris, Director of Support and Chief Engineer at the British Royal Air Force.
Norway’s Chief of Defence, Erik Kristoffersen, explains that Norway started using flight simulators – chambers that resemble pilot cockpits. “With our F35, we use simulators that are so good that we can do more training in less time. As we do not need to do safety preparation (to fly), we do not damage our existing fleet which then requires less maintenance,” he says.
How are militaries managing heat?
Rising global temperatures pose a significant challenge to military readiness. By 2050, regions like the Middle East could face daytime highs of 50°C and nighttime lows of 30°C for extended periods.
As droughts and wildfires grow more frequent, militaries must adapt their equipment and strategies to operate effectively in unpredictable and hazardous environments.
To protect personnel and maintain performance in such extreme conditions, armies are launching heat management strategies – including heat-reflective or cooling-system uniforms, and smart energy systems that can make infrastructure climate-resistant.
These innovations not only safeguard soldiers but also improve efficiency during humanitarian operations, such as disaster relief, which are increasingly needed in heat-ravaged regions.
Is greening the military achievable?
Defence emerged as a clear winner in this year’s national budgets, as NATO countries are working to meet the alliance’s target of allocating two per cent of their GDP to defence spending in the face of escalating geopolitical tensions.
In 2021, NATO adopted a Climate Action Plan, with the ambitious target of achieving net-zero emissions by 2050. “This was the recognition that the world’s largest military alliance views climate change as a security issue and understands it must act,” Kabbej explains.
Countries also have a vested interest in speeding up investment in green technology for operational advantages. For instance, hybrid-electric technologies provide significant stealth benefits due to their near-silent operation – especially during final approaches to targets. Using hydrogen fuel cells to power vehicles eliminates thermal signatures, rendering them virtually invisible to thermal detection systems.
“Military systems often have lifespans of 20 to 30 years, meaning that achieving net zero by 2050 requires immediate action to avoid locking in carbon-intensive technologies,” says Constantinos Hadjisavvas, project manager at the European Defence Agency (EDA).
Weir says that, in the meantime, transparency in military emissions reporting would help understand the true scale of its emission contribution and “how much of our dwindling carbon budget should be allocated to defence, at the expense of other sectors.”
But despite NATO’s climate action plan and various national initiatives, sustainability remains a secondary concern for many defence sectors.
France’s Climate Advisor to the Armed Forces Alex Bastienne told a defence conference that the country’s primary climate focus will be on improving energy efficiency, rather than broader sustainability reforms.
“Given the delays in climate action within the civilian sphere, and the geopolitical context, it is unfortunately possible that climate adaptation may not be prioritised, despite the increasing vulnerability of even the world’s most powerful militaries to the impacts of climate change,” says Kabbej.
Moreover, Weir argues, “These increases in spending are translating directly into increasing military emissions and driving a climate crisis that militaries argue is a threat to national security.”
