The Pentagon stomps the Earth with a colossal carbon footprint. A new report has shown that the US pumps out more greenhouse gas emissions through its military alone than most countries, including industrialized nations such as Sweden, Denmark, and Portugal.

The US spends more money on its military than any country in the world: an eye-watering $700 billion each year. This vast force is primarily powered by fossil fuels, resulting in the emission of around 59 million tonnes (65 tons) of carbon dioxide and other greenhouse gases each year. If the US military was to be considered a nation, it would be the 55th largest contributor of greenhouse gases in the world.

The report, part of Brown University’s “Costs of War” project, set out to evaluate US military fuel use during their post-9/11 wars and the impact of that fuel usage on greenhouse gas emissions – or "freedom gas” as the US Department of Energy likes to call it. It concludes that the Pentagon's defense operations emitted a total of 766 million tonnes (844 tons) of greenhouse gas between 2001 and 2017. The majority of this, approximately 70 percent, was produced through the transportation of troops and equipment.

Ironically, climate change is widely expected to become a huge threat to national security in many parts of the world, even by the Pentagon's own admissions. In 2014, they released a report that concludes: “The pressures caused by climate change will influence resource competition while placing additional burdens on economies, societies, and governance institutions around the world.”

“These effects are threat multipliers that will aggravate stressors abroad such as poverty, environmental degradation, political instability, and social tensions – conditions that can enable terrorist activity and other forms of violence,” the report continued. 

In other words, while the US Department of Defense is bracing for climate change to create a more chaotic and dangerous world, it is simultaneously adding to the problem by pumping out vast quantities of greenhouse gases.

Furthermore, the US is on track to continue a heavy military presence around the Persian Gulf to maintain its access to – you guessed it – oil.

But is there a way out of this vicious cycle? The good news is that the Pentagon has increased its use of renewable energy since 2009, despite being involved in wars across Afghanistan, Iraq, and Syria. It has also invested huge amounts of money into solar energy generation and other clean energy sources. Nevertheless, more needs to be done.

“I agree with the military and national security experts who contend that climate change should be front and center in US national security debates. Cutting Pentagon greenhouse gas emissions will help save lives in the United States, and could diminish the risk of climate conflict,” lead author Neta C Crawford, Professor of Political Science and Department Chair at Boston University, wrote in an article for The Conversation.