The National Security Impacts of Climate Change

This issue brief examines how climate change impacts United States national security, detailing the Department of Defense's (DOD) conceptualization of climate change as a 'threat multiplier' and the resulting operational, infrastructural, and geopolitical challenges. It outlines the adaptation and mitigation strategies adopted by the DOD and other security agencies, while analyzing the role of Congressional legislation and funding in shaping these efforts.

• The U.S. Department of Defense (DOD) views climate change as a 'threat multiplier,' meaning it amplifies existing global stressors such as poverty, political instability, and social tensions, which can lead to increased conflict and instability.
• Climate change increases the burden on DOD personnel and assets tasked with humanitarian assistance and disaster relief (HADR) both domestically and internationally, as evidenced by responses to Typhoon Haiyan in 2015 and Super Storm Sandy in 2012.
• DOD infrastructure is highly vulnerable to climate change, with a global real-estate portfolio of 562,000 buildings across 4,800 sites valued at approximately $850 billion in replacement costs. Risks include sea level rise, flooding, and wildfires, which can disrupt training and operational readiness.
• Climate-induced population displacement creates significant security risks, as 'environmental migrants' lack the legal protections of refugees. This displacement can lead to direct risks for border security, indirect economic disruptions, and third-order risks such as conflicts over scarce resources, as seen in Darfur and Syria.
• Water scarcity is projected to increase intra- and inter-state conflict, particularly in North Africa, the Middle East, and South Asia by 2040. This includes the 'weaponization of water,' where groups like the Islamic State and Al-Shabaab use water resources for strategic, tactical, or coercive purposes.
• The melting of Arctic sea ice—which has decreased by 13.5 percent per decade since 1979—is opening new navigation routes and access to undiscovered oil (13%) and natural gas (30%). This creates geopolitical tension and reveals a U.S. capability gap, as the U.S. has only one operational icebreaker compared to Russia's 27.
• U.S. military branches have implemented specific energy and resilience initiatives: the Navy's 'Great Green Fleet' tested biodiesel blends; the Marine Corps focused on reducing expeditionary fuel dependence; the Army's Net Zero Initiative and Office of Energy Initiatives promote renewable energy; and the Air Force is assessing coastal erosion risks in Alaska.
• Congressional action on climate security has been inconsistent; while the 2010 Quadrennial Defense Review and the FY2018 NDAA integrated climate risks, the House version of the FY2017 NDAA explicitly forbade using appropriated funds for climate adaptation measures.

APA

La Shier, B., & Stanish, J. (2017). The National Security Impacts of Climate Change. Environmental and Energy Study Institute. https://www.eesi.org/papers/view/issue-brief-the-national-security-impacts-of-climate-change

Chicago

La Shier, Brian, and James Stanish. The National Security Impacts of Climate Change. Environmental and Energy Study Institute, 2017. https://www.eesi.org/papers/view/issue-brief-the-national-security-impacts-of-climate-change.

Wikipedia

{{cite report |last1=La Shier |first1=Brian |last2=Stanish |first2=James |title=The National Security Impacts of Climate Change |publisher=Environmental and Energy Study Institute |date=20 December 2017 |url=https://www.eesi.org/papers/view/issue-brief-the-national-security-impacts-of-climate-change |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{lashier2017national, author = {La Shier, Brian and Stanish, James}, title = {{The National Security Impacts of Climate Change}}, institution = {Environmental and Energy Study Institute}, year = {2017}, month = dec, url = {https://www.eesi.org/papers/view/issue-brief-the-national-security-impacts-of-climate-change}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }