Study finds massive Defense Department carbon emissions

America's Defense Department uses more oil and emits more greenhouse gases than any other institution on Earth, according to a new Brown University study.

The impact: The study found that if the Pentagon, which oversees the U.S. military, were a nation, its emissions would rank it as the world's 55th largest contributor of greenhouse gases. The department has been responsible for some 80% of all U.S. government energy consumption since 2001.

Our thought bubble via Axios' Ben Geman: The Defense Department requires massive amounts of jet fuel, diesel and other liquid fuels. Power usage at military installations also contributes.

Context: U.S. energy consumption declined after the end of the Cold War, until the U.S. invaded Afghanistan in 2001 in response to 9/11, the study finds. In 2005, energy consumption by the DOD "hit its highest level in a decade."

Methodology: "The Pentagon does not publicly and regularly report its fuel consumption or greenhouse gas emissions, and there is no official publicly available DOD source for all military greenhouse gas emissions."

• "It is possible, however, to estimate the overall greenhouse gas of the U.S. military using publicly available emissions data from the Department of Energy for recent years. ... This data allows an estimate of how much of these emissions may be attributable to war."

The report points out: "The military uses a great deal of fossil fuel protecting access to Persian Gulf Oil. Because the current trend is that the U.S. is becoming less dependent on oil, it may be that the mission of protecting Persian Gulf oil is no longer vital and the U.S. military can reduce its presence in the Persian Gulf."

Reality check, via Axios' Amy Harder: President Trump is bullish on the military — and dismissive of climate change, so any efforts to cut down on the Pentagon's energy use are unlikely to come under his leadership.

Go deeper: Earth's carbon dioxide has jumped to the highest level in human history