In the cacophony of climate discourse, a silent giant remains unmeasured: the carbon footprint of armed conflict. While nations convene to debate energy transitions and net-zero targets, the world’s militaries burn roughly 5% of global fossil fuels, yet their emissions are systematically excluded from international climate agreements. This omission is not a trivial oversight; it is a deliberate structural blind spot that undermines scientific accuracy and policy effectiveness.
Consider the data from the 2022 Stockholm International Peace Research Institute report: global military spending reached $2.24 trillion, a figure that correlates directly with fuel consumption. The US Department of Defense alone consumed over 100 million barrels of fuel in 2021, making it the single largest institutional emitter on Earth. These emissions are not accounted for under the Kyoto Protocol or the Paris Agreement, as nations argue that national security concerns trump climate transparency.
The problem extends beyond direct fuel use. War’s environmental legacy includes the embodied carbon of weapon manufacturing, the methane released from damaged oil infrastructure, and the deforestation caused by conflict zones. A 2023 study in the Journal of Cleaner Production estimated that the full lifecycle emissions of the US military exceed 500 million tonnes of CO2 annually, equivalent to the entire carbon output of the United Kingdom. Yet these figures are absent from the emissions inventories reported to the UN.
This is not a call for pacifism but for accounting. If we are to address climate change with the urgency it demands, we cannot afford to ignore 5% of global emissions. The military sector has a responsibility to decarbonise, just as aviation and shipping are being pressed to do. Technologies exist: naval vessels can be retrofitted with hybrid propulsion, military bases can install solar microgrids, and cleaner fuels can power aircraft. The US Joint Renewable Energy Program already saves millions of barrels of fuel annually, proving that security and sustainability are not mutually exclusive.
The silence on this subject is maintained by the same geopolitical inertia that blocks broader climate action. But the physics of planetary warming does not respect military secrecy. Every tonne of CO2 warms the atmosphere regardless of its origin. If we continue to treat war as a climate exception, we are effectively choosing to accelerate the very destabilisation that conflict thrives on. Drought, food shortages and mass migration are already multiplying tensions worldwide. Ignoring military emissions is not just scientifically unsound; it is a short-sighted strategy that undermines long-term security.
As a climate scientist, I am tired of explaining this. The numbers are clear. The solutions exist. What is missing is the political will to include the most powerful institutions in the same carbon calculus as the rest of humanity. We cannot bomb our way out of the climate crisis. It is time to disarm our emissions.
