While steadily recognizing climate change as a top threat to national security, the Pentagon continues to produce more carbon emissions than some mid-sized European economies, thanks largely to troop deployments intended to protect its access to oil in the Persian Gulf.

Quite apart from the climate costs, such an ironic, self-defeating circle makes neither economic nor political sense, writes The Independent, reporting on a recent Brown University study on the cost of war.

Responsible for approximately 60 million tonnes of CO2 emissions in 2017, the U.S. Department of Defense (DOD) out-pollutes both Portugal and Sweden, which rank 57^th and 66^th, respectively, in the Global Carbon Atlas. The Pentagon is also wildly inefficient, the Brown study found, with emissions relative to spending that exceed the equivalent by the British Ministry of Defense nearly six-fold.

“Using and moving troops and weapons accounted for around 70% of the Pentagon’s energy consumption, mostly due to the burning of jet and diesel fuel,” said report author Neta Crawford. All told, The Independent adds, the DOD “accounts for roughly 80% of all U.S. government energy consumption,” even after delivering a significant drop in fuel use since 2009 thanks to more energy-efficient vehicles and cleaner energy sources on bases.

Crawford said the U.S. could cut back on heavily fuel-dependent troop deployments to the Persian Gulf, reducing the greenhouse gas emissions they represent, as renewable energy makes it less and less necessary to defend oil supplies. The overall reduction in oil dependence would also make U.S. troops less vulnerable to attack.

Widening her lens, she added that reducing fuel use would also enable the United States government to “decrease its military spending and reorient the economy to more economically productive activities”.