We have heard from the scientists on climate change, with their meticulous data on ecosystem degradation and species loss. We have heard from the climate deniers, with their desperate attempts to deploy countervailing arguments. Both groups have mobilized substantial blocs of voters in pivotal countries, producing gridlock in global efforts to slow the pace of global warming. It is time, then, to hear from another group of informed and influential professionals: senior military officers.

Military leaders have not said much in public about global warming, in part because they’re reluctant to become involved in partisan political issues (as climate has become) and partly because top government officials—in the United States, at least—have actively discouraged such involvement. Nevertheless, senior officers are fully aware of warming’s deleterious effects and have devised a thorough analysis of its strategic implications. As I demonstrate in my new book, All Hell Breaking Loose: The Pentagon’s Perspective on Climate Change, senior American officers believe that global warming is already threatening the survival of many poor, resource-deprived countries and poses a significant risk to even the wealthiest of nations.

“Climate change is an urgent and growing threat to our national security, contributing to increased natural disasters, refugee flows, and conflicts over basic resources such as food and water,” the Department of Defense (DoD) told Congress in a 2015 memorandum. “These impacts are already occurring, and the scope, scale, and intensity of these impacts are projected to increase over time.”

In this, and other Pentagon documents, senior officials have identified three main pathways by which climate change is likely to endanger American security: by increasing the level of conflict and chaos abroad; by exposing the homeland to ever more destructive climate effects; and by obstructing the military’s capacity to carry out its assigned missions.

As global temperatures rise, Pentagon officials fear, essential resources will dwindle in many poor and divided countries, provoking conflict among internal factions and threatening the survival of fragile governments. In this chaotic environment, terrorist groups will flourish while dispossessed farmers will migrate in search of jobs—typically encountering hostility wherever they go. All this instability, the generals fear, will result in deadly pandemics, incessant warfare, and a relentless call on the United States to provide humanitarian relief and troop support.

Equally worrisome, in the generals’ view, is the likelihood that climate change will cause grave harm to the homeland. The nation’s East and Gulf Coasts are highly exposed to powerful hurricanes while its West and Southwest are vulnerable to prolonged droughts and forest fires. To make matters worse, scientists fear that extreme events of this sort will increasingly occur in clusters, with one disaster following immediately after another—much as Hurricanes Irma and Maria followed Harvey in August-September 2017.

For the US military, the prospect of an increasing frequency of storm clusters is deeply troubling, as the armed forces will repeatedly be called upon to assist local authorities in providing relief services, diverting them from other core responsibilities. “More frequent and/or more severe extreme weather events,” the Pentagon affirmed, “may require substantial involvement of DoD units, personnel, and assets in” future relief operations.

This will be made all the more challenging by the prospect of climate-related threats to the military’s own mobilization capabilities. The same storms that devastated much of the southeast in 2017 also battered numerous bases, resulting in the mandatory evacuation of most personnel. A similar predicament arose in 2018, when Hurricanes Florence and Michael produced severe damage to several key installations in Florida and the Carolinas.

All this leads to what might be called an “all hell breaking loose” scenario—a situation in which key US allies are begging for American troop support to avert collapse while the homeland is reeling from several major climate disasters and vital military installations are incapacitated by storms or wildfires.

For the US military, this would pose an existential threat, preventing it from carrying out its fundamental mission of defending the nation. To overcome this peril, the armed forces have undertaken a wide range of initiatives to enhance their capacity to resist warming’s harsh effects and to reduce their own contributions to climate change. These have included, for example, the construction of sea walls at low-lying coastal bases and major investments in renewable energy. They have also partnered with the militaries of other countries to undertake similar initiatives.

There is much that all of us—environmentalists, denialists, and ordinary citizens—can learn from this prognosis. To begin with, it appears that we should be paying greater attention to how human societies will be imperiled by warming’s harsh effects and perhaps less to the plight of natural habitats; both are important, but our ability to survive future climate calamities will depend most of all on the resiliency of human institutions. Likewise, for denialists, it is evident that the time for dispassionate scientific discussion has passed and that climate change is already causing mortal harm to the nations they claim to cherish.

Finally, for the rest of us, it should become evident that climate change will come in time to supersede all other threats to national security, requiring an even greater popular response than that now devoted to other, more familiar threats. Like the military, we will have to build strong barriers to rising seas and other climate perils, take major steps to reduce our carbon emissions, and, most importantly, collaborate with other states to advance these efforts on a global scale.

Michael Klare is the professor emeritus of peace and world security studies at Hampshire College and the author of 15 books, including All Hell Breaking Loose: The Pentagon’s Perspective on Climate Change (Metropolitan Books)



