Militaries are concerned about climate change because it is their job to address all credible threats to their respective nation’s security. These threats come in forms both direct and indirect, including direct threats to military installations from sea level rise and extreme droughts, and indirect threats through the exacerbation of instability in critical regions. Climate change presents risks to three elements of military effectiveness: readiness, operations and strategy.

Readiness: Readiness refers to the ability of a military to carry out operations in a timely manner. This involves having a stable and secure military infrastructure, including bases, supplies and logistics, in order to carry out missions. Climate change effects such as sea level rise have the ability to compromise coastal military installations that are critical for such operations. Other extreme weather events, such as droughts and flooding, can also put stresses on critical military infrastructure.

Operations: Climate change effects impact military operations, whether they be war-fighting operations or humanitarian missions. For example, climate change can place significant burdens on the supply chains and logistical capacity of armed forces engaged in “theater.” Extreme drought or flooding in areas where militaries are engaged in warfighting, for example, can compromise water supply lines, and thus threaten military personnel directly. Extreme drying can also increase the likelihood of non-state actors using the seizure of water resources as leverage against populations and adversaries. An increase in the frequency and intensity of natural disasters may also put strains on the capacity of armed forces to deliver humanitarian assistance and disaster relief (HADR).

Strategy: Climate change can impact military strategy through increasing the possibility of destabilizing conditions in strategically-significant regions of the world. In the Arctic, a melting ice cap, coupled with increasing tensions between Russia and other Arctic nations, could increase the likelihood of conflict. In the Middle East and North Africa, climate change effects on water security may increase the probability of instability in the future. In Central Asia, increases in glacial melt and flooding, coupled with existing security dynamics (such as terrorism and nuclear materials proliferation), can create a volatile mix. In the broader Asia-Pacific region, rainfall variability will interact with a growing urban and coastal population, as well as an increasing demand for energy, to present enormous challenges to security in this increasingly important part of the world. Migrating fish stocks in the South China Sea may create pressures on the fishing industry to move into contested water, leading to increased tensions between China, its neighbors and the United States. These risks can increase the likelihood of militaries being called on to resolve conflicts, or provide post-conflict assistance. All of these dynamics will put stresses and strains on military strategies.

Read more:

2015: Be Prepared: Climate Change, Security and Australia’s Defence Force, Climate Council
2015: El Nino: Potential Asia Pacific Impacts: U.S. Pacific Command
2015: National Security Implications of Climate-Related Risks and a Changing Climate, U.S. Department of Defense
2014: Department of Defense Strategic Sustainability Performance Plan FY2014: Department of Defense
2014: Climate Change Adaptation Roadmap, U.S. Department of Defense
2014: National Security and the Accelerating Risks of Climate Change, CNA Corporation
2014: Quadrennial Defense Review, U.S. Department of Defense
2014: US Navy Arctic Roadmap: U.S. Department of the Navy
2014: Environmental and Energy Issues for the Military. Environment and Energy Security for the Americas, Military Resiliency and Readiness. Environmental and Energy Collaboration Group (EECG)
2013: US Coast Guard Arctic Strategy, U.S. Coast Guard
2013: SERDP, Assessing Impacts of Climate Change on Coastal Military Installations: Policy Implications
2013: 2013 Addendum to the FY2012 Climate Change Adaptation Roadmap: Department of Defense
2013: Arctic Strategy: Department of Defense
2013: NATO Centre of Excellence for Crisis Management and Disaster Response: Conference Details, “Visualizing Implications Of Climate Change On Military Activities And Relationships”
2013: Australian Government: Strong and Secure – A Strategy for Australia’s National Security
2013: The Global Security Defense Index on Climate Change Preliminary Results: National Security Perspectives on Climate Change from Around the World. Holland, A. and Vagg, X.
2013: Planning for Complex Risks: Environmental Change, Energy Security and the Minerva Initiative. Briggs, Chad.
2012: Department of Defense FY 2012 Climate Change Adaptation Roadmap: Department of Defense
2012: Department of Defense Strategic Sustainability and Performance Plan FY2012: Department of Defense
2011-2012: Key Strategic Issues List: U.S. Army War College
2011: Department of Defense Strategic Sustainability Performance Plan FY2011: Department of Defense
2011: Incorporating Sea Level Change Considerations in Civil Works Programs: U.S. Army Corps of Engineers
2011: Defense Science Board Task Force Report: Trends and Implications of Climate Change for National and International Security: Department of Defense
2011: The National Military Strategy of the United States of America: Redefining America’s Military Leadership: Chairman of the Joint Chiefs of Staff
2011: National Security Implications of Climate Change for U.S. Naval Forces: Naval Studies Board, Division on Engineering and Physical Sciences
2010: Quadrennial Defense Review Report: Department of Defense
2010: The Joint Operating Environment, Ready for Today, Preparing for Tomorrow: United States Joint Forces Command
2010: Climate Change Impacts and AFRICOM: A Briefing Note: Institute for Defense Analyses, Christine Youngblut
2010: Organization for Security Co-operation in Europe (OSCE): Shifting Bases, Shifting Perils: A Scoping Study on Security Implications of Climate Change in the OSCE Region and Beyond
2010: U.S. Navy Climate Change Road Map: Task Force Climate Change, Department of the Navy
2009: US Navy Arctic Roadmap: U.S. Department of the Navy
2009: Taking Up the Security Challenge of Climate Change: U.S. Army War College
2009: Climate Change Effects: Issues for International and US National Security: Institute for Defense Analyses, Christine Youngblut
2008: The National Security Strategy of the United Kingdom: Security in an interdependent world
2008: National Defense Strategy: Department of Defense
2007: A Cooperative Strategy for 21st Century Sea Power: Department of the Navy, the Marine Corps and the Coast Guard
2007: The Joint Operating Environment, Trends and Challenges for the Future Joint Force Through 2030: United States Joint Forces Command
2007: National Security and the Threat of Climate Change: Center for Naval Analysis
2003: An Abrupt Climate Change Scenario and Its Implications for United States National Security: Pentagon Office of Net Assessments