Today, I am a member of Operation Free, a national coalition of veterans who believe that climate change and our dependence on fossil fuels is a threat to America’s national security. These men and women have walked the burning oil fields of Iraq and patrolled the mountain roads of Afghanistan—where the fully-burdened cost of fuel is $30 a gallon and 1 in 24 fuel convoys ends in an American casualty. It is an established consensus in the defense community that our energy posture directly impacts our country’s safety.

America sends more than $1 billion a day overseas for oil. It should not be a surprise, then, that oil is the single largest contributor to our foreign debt, outpacing even our trade deficit with China. Worse, far too many of those dollars wind up in the hands of regimes that wish us harm.

According to the CIA, more than 50 percent of Iran’s entire budget comes from the oil sector. For every $5 rise in the price of a barrel of crude oil, Iran receives an additional $7.9 billion annually. That’s 7.9 billion dollars to build new nuclear facilities, replace centrifuges and support terrorist groups that threaten Americans and target our Israeli allies.

What’s more, there is another consensus emerging in the defense community: climate change poses a serious threat to our national security. While some in Congress may not believe that climate change is real, our country’s national security professionals do. The Pentagon’s Quadrennial Defense Review, the military’s most important strategic document, states that climate change is “an accelerant of instability and conflict” and that climate change and reliance on fossil fuels are “prominent military vulnerabilities” for the nation.

And, according to a recent study, more than 97 percent of climate scientists say that man-made climate change is a reality.

I’m not a climate scientist—but I am a former front-line combat leader in the US military. And as a combat leader, if 97 percent of my intelligence indicated that I was about to face a lethal danger that would risk the lives of my paratroopers, I would be committing unconscionable malpractice if I did not listen and act.

Fortunately, some leaders are acting in the same vein.

Kern County, California—where unemployment had been 64 percent higher than the national average—supplied the crude oil that fueled much of the mid-20th century oil boom. Today, Kern County continues to provide American energy to Californians, but through 21st century technologies like wind and solar power. These clean technologies are creating American jobs that can’t be outsourced. And many of these jobs are going to our nation’s returning troops.

Two months ago, I met Jeff Duff, the CEO of Air-Streams Renewables, a technical school in Kern County that trains wind turbine technicians.  Air-Streams is proud that 70 percent of its graduates are veterans. One of Jeff’s students, a naval electrician, struggled to find work after leaving the service. He left a night job at a mortuary to join Air-Streams and graduated at the top of his class. Now, he’s serving his community by building the energy economy of the future.

As Congress debates clean technologies, lawmakers often ignore energy’s impact on America’s national security. They focus on the costs that we can measure with a balance sheet. But the price of fossil fuels includes more than searching, extracting and shipping. There are security costs that we must recognize, even if they are harder to measure. Fossil fuels fund extremists, and breed dependency on nations that don’t share our values. Those are costs that affect not only Exxon and Shell, but ordinary Americans across the country.

Today, we face a choice on our national security. Either we can leave our military vulnerable to the pernicious effects of climate change and our dependence on oil, or we can lead the way by investing in 21st century technologies that keep America safe and prosperous.

Breen is the Vice President of the Truman National Security Project and an Operation Free Veteran.