Every hour, the U.S. military burns enough energy to power a midsize American city for a week.
But a new analysis suggests that when Washington tightens the Pentagon’s purse strings, that ravenous appetite for oil drops—fast. If sustained cuts to defense spending continue, the military could slash its annual energy use by more than what Delaware or Slovenia consumes in a year. And unlike expensive retrofits and fuel efficiency drives, this change costs nothing—except political will.
Defense cuts cut energy harder than they raise it
The U.S. military has long been the world’s biggest institutional consumer of energy—and one of the world’s biggest greenhouse gas emitters. But the study, published in PLOS Climate, reveals an asymmetry: a one percent cut in military spending reduces the Pentagon’s energy use by nearly one percent. Increase the budget by one percent? Energy barely ticks up. “It’s not just what you buy that matters,” the authors write. “It’s what you don’t use.”
In other words: winding down wars and training means parking tanks, grounding planes, and shuttering bases—dramatically reducing fuel burn. Simply adding more dollars doesn’t immediately scale up activity in the same way.
- Military energy use dropped from 1,360 trillion BTUs in 1975 to 622 trillion BTUs in 2022
- Jet fuel alone accounts for more than half of all Pentagon energy use
- Cutting spending by 1% trims vehicle and equipment fuel use by more than 1%
- By 2032, energy use could fall another 5% under steep cuts
Fighting fewer wars is the greenest move
The Department of Defense emits more carbon than many nations—roughly on par with Sweden or Portugal. While recent decades have seen modest drops in emissions, the study argues that budget choices overshadow efficiency gains. “These findings indicate that the main results are largely, but not entirely, driven by changes in jet fuel consumption,” the authors note. Grounding air fleets saves more emissions than any other single action.
Even modest cuts compound. Under a steep-cut scenario modeled through 2032, military energy use would fall to 588 trillion BTUs—akin to erasing the footprint of an entire small country. Keep increasing spending instead, and energy use creeps past 800 trillion BTUs.
The quiet climate lever no one talks about
The Pentagon has long tried to green itself with biofuels and efficient bases. But the researchers argue that reducing deployments and trimming budgets might be the most potent climate policy the DOD has. “Our findings show that sustained cuts to U.S. military expenditures could result in annual energy savings on par with what the nation of Slovenia or the U.S. state of Delaware consumes annually by 2032,” they conclude.
As the world confronts intensifying climate risks, that’s an uncomfortable truth: one of the fastest ways for the U.S. to cut emissions might simply be to fight fewer wars.
Based on: Thombs RP, Jorgenson AK, Clark B (2025) Reducing U.S. military spending could lead to substantial decreases in energy consumption. PLOS Clim 4(7): e0000569. https://doi.org/10.1371/journal.pclm.0000569
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