Reducing U.S. military spending could significantly lower energy consumption and greenhouse gas emissions, according to a new peer-reviewed study published in PLOS Climate. The research highlights how even modest cuts to the Department of Defense (DOD) budget could lead to energy savings equivalent to the annual consumption of entire states.
The study, led by researchers from Penn State University, the University of British Columbia, and the University of Utah, analyzed data from 1975 to 2022 to model the relationship between U.S. military expenditures and DOD energy consumption. They found a directional asymmetry: decreases in military spending lead to much larger drops in energy use than equivalent increases cause in energy growth.
According to the authors, a 1% decrease in military expenditures is associated with a 0.98% drop in DOD energy use, while a 1% increase in spending has no statistically significant long-term effect.
The researchers attribute most of the energy savings to reductions in jet fuel consumption and energy use in military facilities and equipment. Jet fuel alone has accounted for more than 54% of the DOD’s average annual energy use since 1975. The study projects that sustained spending cuts through 2032 could result in annual savings exceeding 272 trillion BTU—on par with what the entire state of Delaware or the country of Slovenia consumes annually.
The team used seven forecast scenarios to simulate how various changes in military spending might shape future energy consumption. Under the most aggressive reduction scenario (a 6.59% annual cut), energy use by 2032 could fall nearly 40% compared to a baseline of historical spending. Even a modest reduction (2.31% annually) could cut usage by more than 100 trillion BTU.
Conversely, if military spending increased at its historical 90th percentile rate (12.28% annually), energy consumption would balloon to levels matching those of El Salvador or Washington, D.C.
The U.S. military is the largest institutional emitter of greenhouse gases globally. From 2010 to 2019, its Scope 1 and 2 emissions alone totaled over 636 million metric tons of CO₂e. Cutting defense spending, the study suggests, may be a viable yet underexplored climate mitigation strategy.
While politically challenging, some leaders have advocated for such cuts. Senators Edward Markey and Bernie Sanders proposed a 10% reduction in 2020, and current Defense Secretary Pete Hegseth has backed an 8% annual cut over the next five years.
The findings also add nuance to debates over military roles in global climate strategy. Although defense institutions often position themselves as actors in climate resilience, higher military budgets correlate with slower international environmental progress and more fossil fuel use.
This research challenges the assumption that military investment is climate neutral or beneficia. Policymakers must consider the emissions implications of defense spending when crafting sustainability strategies.
