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The Department of Defense Must Plan for the National Security Implications of Climate Change

The responsibility of the Department of Defense is the security of our country -- and that requires thinking ahead and planning for a wide range of contingencies. Climate change is a long-term trend, but with wise planning and risk mitigation now, we can reduce adverse impacts downrange.

The responsibility of the Department of Defense is the security of our country. That requires thinking ahead and planning for a wide range of contingencies.

Among the future trends that will impact our national security is climate change. Rising global temperatures, changing precipitation patterns, climbing sea levels, and more extreme weather events will intensify the challenges of global instability, hunger, poverty, and conflict. They will likely lead to food and water shortages, pandemic disease, disputes over refugees and resources, and destruction by natural disasters in regions across the globe.

In our defense strategy, we refer to climate change as a “threat multiplier” because it has the potential to exacerbate many of the challenges we are dealing with today – from infectious disease to terrorism. We are already beginning to see some of these impacts.

A changing climate will have real impacts on our military and the way it executes its missions. The military could be called upon more often to support civil authorities, and provide humanitarian assistance and disaster relief in the face of more frequent and more intense natural disasters. Our coastal installations are vulnerable to rising sea levels and increased flooding, while droughts, wildfires, and more extreme temperatures could threaten many of our training activities. Our supply chains could be impacted, and we will need to ensure our critical equipment works under more extreme weather conditions. Weather has always affected military operations, and as the climate changes, the way we execute operations may be altered or constrained.

While scientists are converging toward consensus on future climate projections, uncertainty remains. But this cannot be an excuse for delaying action. Every day, our military deals with global uncertainty. Our planners know that, as military strategist Carl von Clausewitz wrote, “all action must, to a certain extent, be planned in a mere twilight.”

It is in this context that today I am releasing DoD’s Climate Change Adaptation Roadmap. Climate change is a long-term trend, but with wise planning and risk mitigation now, we can reduce adverse impacts downrange.

Our first step in planning for these challenges is to identify the effects of climate change on the Department with tangible and specific metrics, using the best available science. We are almost done with a baseline survey to assess the vulnerability of our military’s more than 7,000 bases, installations, and other facilities. In places like the Hampton Roads region in Virginia, which houses the largest concentration of U.S. military sites in the world, we see recurrent flooding today, and we are beginning work to address a projected sea-level rise of 1.5 feet over the next 20 to 50 years.

Drawing on these assessments, we are integrating climate change considerations into our plans, operations, and training across the Department so that we can manage associated risks. We are considering the impacts of climate change in our war games and defense planning scenarios, and are working with our Combatant Commands to address impacts in their areas of responsibility.

At home, we are studying the implications of increased demand for our National Guard in the aftermath of extreme weather events. We are also assessing impacts on our global operations – for instance, how climate change may factor into our rebalance to the Asia-Pacific. Last year, I released the Department of Defense’s Arctic Strategy, which addresses the potential security implications of increased human activity in the Arctic – a consequence of rapidly melting sea ice.

We are also collaborating with relevant partners on climate change challenges. Domestically, this means working across our federal and local agencies and institutions to develop a comprehensive, whole-of-government approach to a challenge that reaches across traditional portfolios and jurisdictions. Within the U.S. government, DoD stands ready to support other agencies that will take the lead in preparing for these challenges – such as the State Department, the U.S. Agency for International Development, and the Federal Emergency Management Agency.

We must also work with other nations to share tools for assessing and managing climate change impacts, and help build their capacity to respond. Climate change is a global problem. Its impacts do not respect national borders. No nation can deal with it alone. Today, I am meeting in Peru with Western Hemisphere defense ministers to discuss how we can work together to build joint capabilities to deal with these emerging threats. 

Politics or ideology must not get in the way of sound planning. Our armed forces must prepare for a future with a wide spectrum of possible threats, weighing risks and probabilities to ensure that we will continue to keep our country secure. By taking a proactive, flexible approach to assessment, analysis, and adaptation, the Defense Department will keep pace with a changing climate, minimize its impacts on our missions, and continue to protect our national security.  

Chuck Hagel is the U.S. Secretary of Defense.

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