The Adversary can strike the US homeland, allies, partners, and deployed forces with limited forewarning and overwhelming power projection. The Adversary, with land, sea, and air assets, can concentrate its forces to wreak destruction and mayhem in fragile regions plagued with existing political, economic and social upheaval.

The Adversary’s actions can precipitate (sic) huge movements of population, stressing border security and creating massive humanitarian crises, including starvation and disease; it can even unleash vector-borne biological agents like malaria mosquitos. Concurrently, the Adversary’s collateral effects can open up new and dangerous areas of strategic competition for resources and influence.

The Adversary’s panoply of global threats has not gone unrecognized by US policymakers. US Defense Secretary Lloyd J. Austin III writes in the foreword to the 2022 Defense Department Climate Adaptation Plan: “Rising temperatures, changing precipitation patterns and more frequent, extreme and unpredictable weather conditions caused by climate change are worsening existing security risks and creating new challenges.”

Austin adds, “Climate change is increasing the demand and scope for military operations at home and around the world. At the same time, it is undermining military readiness and imposing increasingly unsustainable costs on the Department of Defense.”

These “increasingly unsustainable costs” have yet to be addressed. Austin speaks apocalyptically of “the existential threat of climate change from hurricanes and wildfires that inflict costly harm on US installations and constrain our ability to train and operate.” Dangerous heat, drought, and floods are triggering crises and instability around the world, including possible conflict over the Mekong, Euphrates, and Nile River waters.

At the same time, rising temperatures creating glacial ice retreat are turning the Arctic region into a potential realm of conflict with powers like Russia and China. An Arctic arms race would place considerable stress on US force projection, logistics, and training. In another region, sea level rise in the Pacific menaces DoD assets in Guam, Marshall Islands, and Palau, the latter in danger of being totally submerged.

This Adversary cannot be deterred or managed or mollified through negotiations. The Administration’s FY2024 DoD budget request seeks $5.1 billion in funding for “enhancing combat capability and mitigating climate risk.” This is too little, too late. To begin with, more than 1700 US military installations are located in coastal areas subject to sea-level rise and/or extreme weather conditions.

Tyndall Air Force Base in Florida suffered an estimated $4.7 billion in damage from Category-5 Hurricane Michael in 2018, with as many as 17 stealthy F-22 fighters severely damaged or destroyed at a cost of $2 billion. In September 2018, Hurricane Florence caused an estimated $3.6 billion at Marine Corps Base Camp Lejeune in North Carolina. The Missouri River in March 2019 flooded one-third of Offutt Air Force Base, home to US Strategic Command, at an estimated cost of $1 billion.

Climate extremes can even degrade operations of the US nuclear deterrent triad, according to a 2023 Carnegie Endowment report. All these vulnerabilities point up the necessity for extensive and expensive hardening of military installations and weapon systems to mitigate damage from climate change.

Ironically, the Pentagon has served as The Adversary’s unintentional ally, since the DoD is the world’s largest single user of petroleum and, as a result, the largest single producer of greenhouse gases in the world. Military deployments are enormous, largely unregulated polluters, as are military training exercises. Warfare itself inevitably brings on environmental calamities; Ukraine, Iraq, and Gaza are ecological disasters in the making.

To its credit, the Pentagon has taken some steps to reduce its carbon footprint, but this is, again, too little too late. Inevitably, the climate change challenge will necessitate a complete paradigm shift in the role of US armed forces as the globe hurdles toward a cataclysmic warming in the next two decades.

The Pentagon must respond to this “existential threat” by recasting its mission to elevate climate change to a primary national security priority that complements deterrence of war and protection of the homeland. In conjunction with other Federal agencies, DoD must implement provisions of President Biden’s Executive Order 14008 “to seize the opportunity that tackling climate change presents.” Beyond this commitment, the Administration needs to articulate and begin applying a global strategy for mitigating environmental disaster, with the US armed forces playing an integral role. In the end, the only option is for the Adversary to extract “increasingly unsustainable costs.”

Dr. Robert Rudney is a retired Senior Adviser in the US Department of the Air Force.