Climate Change and the Risk to U.S. National Security

Norfolk Naval Base

Providing for the common defense of these United States is one of the primary purposes of our Union, and the framers of the Constitution saw to it that the new government was given the authority to raise and maintain the forces necessary to do so. In the nearly 230 years since constitutional ratification, the manner in which we “raise and support Armies” and the resources allotted to “provide and maintain a Navy” have been a frequent and proper matter of political debate, but the central concept of a common defense as a constitutional duty of our federal government has never been a partisan issue.

This is largely because our elected leaders have generally understood that the United States of America is a maritime nation, wherein our economic security relies upon freedom of the seas and the assured flow of resources and commerce. But providing for our national security in today’s complex operating environment also means promoting stability, deterring conflict, and managing risk. In so doing the U.S. Department of Defense (DoD) continually analyzes U.S. strategic objectives and potential threats, and since 2006 has increasingly cited the pernicious effects of climate change as a significant threat to our national security.

While a handful policymakers and elected representatives have chosen not to believe that human activity contributes to climate change, or to even accept empirical evidence that the climate is in fact changing, military professionals know that prudent national security planning cannot wait on absolute consensus. Indeed, the realities of climate change have already begun to impact our national security interests, specifically in terms of risk to vital infrastructure and increasing global instability.

The Department of Defense, its agencies, and the Military Services all together own and manage nearly 5,000 sites spread across 40 foreign countries and every state in the nation, comprising nearly 24.7 million acres of real property and assets valued at more than $850 billion. As far back as 2008 the National Intelligence Council judged that more than 30 U.S. military installations were already facing elevated physical and operational security risk from rising sea levels. The most vulnerable infrastructure over the near term is the extensive network of coastal facilities maintained by the U.S. Navy, which includes eight installations on the east coast alone that will lose from 25 percent to 50 of their land area to rising seas by the end of this century. Among these is Naval Station Norfolk in Hampton Roads, Virginia — the largest naval installation in the world and home to five carrier battle groups — which is projected to see four to seven feet of sea level rise over the next 70-80 years.

In addition to rising sea levels, climate change poses numerous other significant challenges for national security and global stability. U.S. intelligence community assessments have concluded that the continued rise in average global temperatures and accelerating severe weather patterns will have significant geopolitical impact, weakening already fragile governments by contributing to food and water scarcity, worsening the spread of disease, and exacerbating the already challenging issue of large-scale migration. These pressures will affect competition for resources, aggravate existing poverty, and create political instability -- all of which make populations more vulnerable to violent extremism and threaten to increase the frequency, scale, and complexity of military operations.

As a party to the congressionally-mandated U.S. Global Change Research Program created in 2009, DoD has joined with twelve other federal agencies to help elected leaders understand, assess, predict, and respond to the impacts of climate change, in part by identifying specific effects in every region of the world, including rapidly retreating glaciers, thawing permafrost, lengthening ice-free seasons in the oceans, earlier snowmelt, and alterations in river flows. But the effects of changing climate on the military operating environment are most perhaps acutely evident in the maritime commons of the Arctic, where rising ocean temperatures and receding ice present significant national and economic security challenges. 

Today the Arctic region is stable and free of conflict. But over the next several decades the Arctic Ocean will become more accessible by those seeking to assert ownership of natural resources and control over key trade routes, ultimately increasing the region’s strategic importance. Competition for rights to mining, oil and gas exploration, and commercial fishing will undoubtedly lead other Arctic states such as Russia, and non-Arctic states such as China, to seek to expand their role in the Region. This will require that DoD cooperate closely with the Department of Homeland Security to protect U.S. sovereign territory and the United States’ broader regional interests.

While climate change alone does not cause conflict, its effects contribute directly to instability and the degradation of life-sustaining infrastructure. DoD has already begun taking actions to improve energy and water security, including investments in energy efficiency and renewable energy technology intended to make our armed forces and military installations more resilient, and the military services have committed to maintaining the capability to operate amid these challenges.

However, ongoing emissions of greenhouse gases will continue to cause further warming, leading existing threats to multiply and exposing our national and economic security interests to exponential risk. DoD can manage this risk, but truly providing for the common defense is the responsibility of our elected leaders. To protect the American people, our natural resources, and our sovereign rights, it is imperative that each and every member of Congress takes action to ensure substantial and sustained reductions of greenhouse gas emissions.

Matthew W. Morgan, LtCol., USMC (Ret.) • Co-founder of Cross the Aisle for Climate


Bibliography and Additional Resources

Center For Naval Analyses, “National Security and the Threat of Climate Change”

U.S. Navy Climate Change Roadmap, May 2010

U.S. Navy Office of Energy, Environment and Climate Change

National Security Implications of Climate-Related Risks and a Changing Climate

DoD Directive 4715.21 Climate Change Adaptation and Resilience

DoD Climate Change Adaptation Roadmap

NOAA 2016 Arctic Report Card

2014 DoD Quadrennial Defense Review

2010 DoD Quadrennial Defense Review

A Cooperative Strategy For 21st Century Seapower

DoD 2014 Base Structure Report

U.S. National Strategy for the Arctic Region