A new study led by Ryan Thombs of Penn State University has found that the U.S. military is the single largest institutional source of greenhouse gas emissions in the world. Published on July 2 in PLOS Climate, the research highlights the significant environmental impact of the Department of Defense (DOD) due to its vast global operations.
The study points to a range of military activities contributing to these emissions — from operating bases and running training exercises to research, development, and the worldwide transportation of troops, equipment, and weaponry. These energy-intensive operations result in massive carbon output.
Ironically, U.S. military officials have acknowledged climate change as a serious threat to national and international security. Previous research has also shown that higher military spending often correlates with increased national emissions.
Thombs and his co-authors argue that reducing U.S. military expenditures could be a powerful step toward curbing energy use and greenhouse gas emissions — potentially saving as much energy as an entire small country consumes.
According to the Public Library of Science, few studies have previously connected military budgets with actual energy consumption. To address that gap, the research team analyzed public data on U.S. defense spending and DOD energy usage from 1975 to 2022.
Their statistical analysis revealed a clear trend: when military spending declines, energy consumption also falls. Notably, the energy savings from spending cuts are more significant than the energy increases tied to spending hikes. The most substantial reductions were linked to decreased use of facilities, vehicles, equipment — especially jet fuel.
Using this data, the researchers modeled projections for 2023 to 2032 based on various spending scenarios. Their forecasts indicate that sustained reductions in military budgets could, by 2032, save as much energy annually as the entire state of Delaware or the country of Slovenia consumes.
The authors stressed that this relationship between defense spending and energy use deserves greater attention — especially in light of the urgent need to address climate change.
“Our findings suggest that even modest cuts to U.S. military spending could yield energy savings equivalent to the annual consumption of a small nation,” the study concludes.Tools
