We have a tendency to view certain public policy issues as wars. As in:  The War On Drugs, Cancer, Poverty... fill in the blank. It is often a misleading analogy, but it is meant to get the public to respond to a dire need, just as they would in wartime.

The terminology, however, is entirely accurate -- and literal -- when it comes to our need to address the changing environment as "the war on climate change."

Recently, President Obama raised the stakes on an issue that tends to pit environmentalists against big oil companies, in what too many view as a domestic fight. Claiming that climate change is an immediate national security challenge, President Obama spoke to the graduates of the U.S. Coast Guard Academy, the uniformed men and women who will most directly be impacted by the world's warming weather patterns and the rising seas.

For several years now, the administration has made references to climate change as a security threat. But not until today has the president laid out what that actually means to our uniformed personnel and what denying those changes means for the nation's safety.

It is about time. As someone in homeland security, I am often asked what is my biggest fear: a pandemic, a terrorist, a loose nuke? All are risks, of course, but the one phenomenon that may have the most likely capacity to alter whatever global stability we can muster at any given moment has to do with Mother Nature.

Indeed, the argument the president made is more sophisticated than the fact that wars often begin because of the fight over limited resources. What is unique about this message is the recognition that the changing waters and atmosphere will put pressures on communities that will eventually lead to unrest. That unrest might be war, but it also can manifest itself in all sorts of other ways such as a refugee crisis, overwhelming migration, or humanitarian relief efforts after a disaster. And those will often demand military action by U.S. troops.

In military assessments, the United States now concedes that the security of nations is "being affected by weather conditions outside of historical norms, including more frequent and extreme floods, droughts, wildfires, tornadoes, coastal high water, and heat waves."

These have had an impact on food supplies and demographic trends. The global population is expected to hit 8.3 billion by 2030. About 60 percent (up from the current 50 percent) of people will live in cities, putting greater pressure on agriculture, energy, transportation, and water supplies.

We are not alone in our assessment. From China to Rwanda, Belarus to Brazil, over 70 percent of nations view climate change as a top threat to their national security.

Why? The movement of large numbers of people -- towards food, water or other natural resources or towards calmer climates -- will put stresses on international stability in ways that we can barely imagine. And in that instability, there will be unrest or, possibly worse, radicalization of those who can find no future in their present circumstances.

The world is physically changing and that will put demands on future U.S. military officers. For the Coast Guard in particular, the changes in water -- from the opening of the Arctic Ocean due to warming atmosphere to the devastation we have seen (and will see) in coastal nations -- will bring about a brand new world order.

This administration should know. Now that the Arctic is relatively ice-free for several months each year, a new and lasting occurrence, the administration recently approved offshore drilling in the Arctic, bringing a new challenge to the Coast Guard's response and recovery efforts. Having made the argument, the Administration might want to reconsider its recent budget for the Coast Guard, one that cuts acquisition spending by 17 percent.

But it is not in error by calling out those who still deny the Earth's climate instability. Skeptics of these global seismic shifts are not simply denying science, they are denying safety and security. Until we recognize -- with the immediacy we would if a nation launched missiles against our cities -- that climate change isn't something that can be debated, but must be mitigated or, failing that, adapted to, we will not expend the effort or resources to prepare ourselves to the one phenomenon that we know is coming: simply, the waters are rising and this is a war.

A version of this commentary originally ran on CNN.com. Security Mom is a podcast hosted by Juliette Kayyem that aims to unpack how the strange and secretive world of national security works. Subscribe to the Security Mom podcast in  iTunes.