By: Stephen Cheney, Retired Marines Corps Brigadier General

On the Fourth of July, we celebrate more than American independence. We celebrate a tradition of American leadership — to decide our future and guide global security — that began 240 years ago. And as we celebrate this year, let’s not forget the brave men and women who serve — and have sacrificed — to defend our independence and protect that security. Even more, let’s honor their mission by preventing the very conflicts that they could be called upon to fight.

To do so, we must combat climate change. It’s not just an environmental issue; it’s a global security crisis. The Department of Defense, in its long-term planning documents, has identified climate change as an “urgent and growing threat to our national security, contributing to increased natural disasters, refugee flows, and conflicts over basic resources.”

As a “threat multiplier,” climate change increases the likelihood of conflict while also hindering military readiness. Like gas on a fire, it inflames smoldering conflicts in regions least able to extinguish them. That often means putting American service members in harm’s way.

Take Syria. The National Academy of Sciences determined that climate change most likely caused the multiyear drought that parched the country from 2006 to 2011. When the Arab Spring began in early 2011, the drought became a catalyst for the country’s civil war. That conflict has put Americans in harm’s way, as more and more deploy there.

Far from battlefields, American civilians are in harm’s way too. Climate change contributes to more frequent and more destructive extreme weather events. Combined with sea level rise, these natural disasters — which often require U.S. military personnel to serve as first responders — strain city, state and national resources — and threaten coastal military installations.

Climate change is a matter of national security deserving of our attention and action. We cannot afford to delay. That’s why I support the U.S. Environmental Protection Agency’s Clean Power Plan, which sets the first ever national limits on carbon pollution from U.S. power plants. This plan is the best tool we have to combat climate change right now. And beginning in 2030, the Clean Power Plan will provide up to $54 billion in climate and health benefits per year, including saving 3,600 lives annually.

With the Clean Power Plan, the U.S. can also lead on clean energy. Our military is doing just that by deploying renewable power, energy efficiency technologies and smart grids at bases across the country and around the world. The Marine Corps base in Twentynine Palms is able to generate 90 percent of its own power with clean energy: using solar power, batteries and a co-generation system.

American independence isn’t about leaving the world behind — but leading it forward. And with the Clean Power Plan, the U.S. is leading. In December 2015, 195 nations including the U.S. agreed on the Paris Agreement, committing to cut carbon pollution and keeping climate change in check. The Clean Power Plan is our front-line strategy for addressing our contributions to climate change. If we fail to hold the line, our allies may too.

Unfortunately, some do want us to fail. To protect their own profits, some power companies and legacy utilities — along with their hired guns in some state capitals — have sued to stop the lifesaving rules. On Sept. 27, the full U.S. Court of Appeals for the D.C. Circuit will hear arguments on the case.

The stakes are high. But so is the support for the Clean Power Plan. Two-thirds of Americans support action on climate like the Clean Power Plan. And joining the American public, a broad and diverse coalition of experts, organizations, and elected officials filed briefs in April to defend the Clean Power Plan. Former Secretary of State Madeleine Albright and former Secretary of Defense Leon Panetta lent their voices. They supported the clean air standards because “the problems created by a warming planet — from rising sea levels to severe weather events to the spread of disease — represent a critical and growing national security threat.”

This Independence Day, as we enjoy the parades and picnics, let’s remember the people: the men and women in uniform who have defended our independence and protected our safety. Let’s honor their service with action to prevent future conflicts that would draw them into danger and away from their families. That means we must combat climate change and support the Clean Power Plan. If we don’t, if we allow the threat to build along the horizon, we leave Americans — civilians and service members alike — in harm’s way.

Cheney, a retired Marines Corps brigadier general, is the chief executive officer of the American Security Project, a nonpartisan national security think tank. He is a graduate of the U.S. Naval Academy and served in the Marine Corps for over 30 years.