Climate Change and National Security

The U.S. Department of Defense (DOD) anticipates that climate change will have vast geopolitical impacts, including sea level rise, food and water scarcity, the proliferation of disease vectors, and the risk of mass migration by vulnerable populations to escape these impacts. These risks lead DOD to recognize that "while climate change alone does not cause conflict, it may act as an accelerant of instability or conflict." In other words, the Department of Defense views climate change as a threat multiplier that can amplify and worsen stress factors (such as poverty, environmental degradation, political instability, and social tensions) that are already present around the world.

As one of the first responders to natural disasters, both domestically and overseas, the U.S. military expects to see its resources stretched by more frequent humanitarian missions. Indeed, climate change exacerbates extreme weather, making it more frequent and more deadly.

Climate change is also a direct threat to military operations and installations. Extreme weather events—flooding, drought, and wildfire—all pose a real threat to military assets, as well as to the civilian assets they depend on (such as roads, electricity, and water). Damage inflicted upon defense facilities can cripple the military's ability to respond to a crisis, in addition to costing taxpayers millions of dollars in repairs. Hazardous temperatures and storms can also disrupt scheduled training activities and put personnel at risk. Rising sea levels and more frequent flooding are already putting into question the long-term viability of certain coastal Navy bases (such as Norfolk, VA, the U.S. Navy's largest port), and wildfires in the West have affected military installations, such as Marine Corps Base Camp Pendleton, and forced evacuations.

The Department of Defense has begun accounting for climate change threats in its short- and long-term installation planning, supply chain management, and training. DOD has also undertaken a baseline assessment of its facilities to better understand which sites are the most vulnerable and may require additional protections or even relocation in order to sustain operations as climate impacts begin to exact a steady toll in the future.

The Department of Defense has also pursued climate mitigation measures to lower its carbon footprint and make its resource consumption more efficient. In truth, the military isn't embracing clean, renewable energy and energy efficiency because of its environmental benefits. It is doing so to reduce its reliance on fossil fuels, to lower its costs (DOD is the world’s largest consumer of energy), and to make its bases more autonomous and secure (fuel convoys are particularly vulnerable to enemy attacks, so it is much safer for bases to generate their own power using solar panels and wind turbines).

A growing contingent of Members of Congress have signaled support for addressing the national security impacts of climate change. The 2018 National Defense Authorization Act (NDAA), an annual authorization bill that sets defense funding levels and policies, included provisions for the military to take action on climate. The provisions, which the president signed into law, explicitly named climate change as "a direct threat to the national security of the United States" and directed the Defense Department to prepare for its impacts on vulnerable bases. In 2017, the House passed an amendment stating in clear terms that climate change "is impacting stability in areas of the world both where the United States Armed Forces are operating today, and where strategic implications for future conflict exist.”