A Blueprint for the Department of Defense’s Strategic Assessment of Climate Change

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One could be forgiven for thinking that a rising China is the only threat that the Department of Defense is preparing to confront. China is referred to as the “pacing threat” by senior defense officials, and the top news out of President Joe Biden’s inaugural visit to the Pentagon last month was a new “sprint effort” to review the U.S. approach to China. In that same visit, the president called on the Department of Defense to “rethink” and “reprioritize” security to meet the challenges of the 21st century, including climate change — but it was the China threat that got the “task force” moniker and a named leader that day. Yet in its “Executive Order on Tackling the Climate Crisis at Home and Abroad,” the administration mandated that climate change must now be at “the center of our national security and foreign policy,” a mandate reflected in newly released national security and defense guidance. To that end, the executive order directs the Department of Defense to prepare a comprehensive new “Climate Risk Analysis” in just 120 days — on the same timeline as the China sprint. This analysis, meant to examine the long-term, strategic security risks posed by climate change, demands at least equal investment and attention as the China effort.

Unlike with China, however, the bench of climate security experts in the Department of Defense is appallingly thin, given the lack of focus on the issue under the previous administration. While it is true that throughout the presidency of Donald Trump the Department of Defense was one of the few places in the federal government making progress on climate change policy, most of this progress was focused on nearer-term risks to military bases and infrastructure, not overarching strategy. The public summary of the 2018 National Defense Strategy mentioned China 12 times, climate change zero. The Department of Defense will need to quickly build capacity and get up to speed to be able to deliver the sweeping new strategic efforts called for by the new president.



Secretary of Defense Lloyd Austin appears to understand the importance of climate change to the core defense mission, declaring “there is little about what the Department does to defend the American people that is not affected by climate change.” Nevertheless, the fanfare surrounding the China announcement shows how quickly the U.S. national security community can revert to traditional conceptions of security risks. Under competing pressures, it will be all too easy for the department to fall back on old habits, remaining narrowly focused on the near-term risks of climate change to military infrastructure and equipment, while deprioritizing the full-picture strategic climate analysis that is needed. This would be a mistake.

We’ve written reports like this, and have both led groundbreaking efforts to analyze longer-term climate security risks in public reports and intelligence assessments. Our work shows that the biggest climate risks posed to U.S. national security extend well beyond direct physical impacts on military operations. Left unchecked, climate change effects such as severe heat and drought, more powerful and destructive storms, declining agriculture and rapidly spreading health risks, and multiple meters of global sea level rise will severely disrupt political stability in countries around the world and exacerbate risks of conflict. The issue also cannot be separated from geopolitical competition, with climate change influencing the behavior of competitors and adversaries like China and Russia. Based on our experiences, we propose some basic parameters for the Department of Defense as it begins its climate risk analysis: the what, who, when, where, and how of the assessment. Given the tight timeline for producing the report and the lack of existing expertise and capacity within the Department of Defense on the topic, without careful attention paid at the outset to crafting a product that is useful, accessible, and wide-ranging, the department risks developing a document that sits on a shelf, rather than building critical resilience where U.S. security forces need it.

First, what should be the focus of these assessments? Analyzing climate threats is a maddeningly large task, with complex layers of uncertainty and correlations to sift through. And while climate modeling is a critical piece of the process, this analysis should go far beyond the physical sciences to properly understand the dynamic nature of climate threats. The department should cast a wide net that includes security analysis, as well as an understanding of the social, political, economic, and technological impacts of climate change, to adequately assess how it will alter the security landscape. The climate risk analysis should also reflect a broad, nuanced understanding of national security and defense because climate change impacts are so wide-ranging. The push to widen the aperture of the national security definition is championed by the Biden administration, as shown in its interim national security strategic guidance, which puts the climate crisis, racial justice, and the global pandemic on par with the threats from China and Russia. This is a sharp departure from the previous administration, and traditional conceptions of the Defense Department’s areas of responsibility. Limited climate security analyses focused just on specific impacts to military infrastructure, for example, won’t capture the full spectrum of this broader definition.

Next, who should be involved in this effort? Addressing climate change in a way that’s commensurate to the threat will take ambitious collective action. So while the project should move quickly to meet the 120-day goal, it need not sacrifice inclusivity for speed. The team leading the risk assessment should include perspectives from across the Department of Defense, including the combatant commands, the services, the Joint Staff, and the Office of the Secretary of Defense. The report’s authors should also seek input early on from other national security agencies, such as the State Department and USAID, recognizing the cross-cutting nature of climate risks. The Department of Defense should also leverage insights from global allies and partners. In the past few years, NATO, the European Union, and the United Nations have all begun work on climate risks, and bodies like the International Military Council on Climate and Security have been created to identify key threats and best practices worldwide. The more the United States can do now to integrate input from its allies and partners into its risk assessments, the more informed and efficient work together will be in the future.

It’s also critical that the Department of Defense carefully select the when of this analysis. The report should take a longer view than many previous departmental assessments. This is not a unique approach for security threat assessments — a recent report on security developments related to China had a twenty-year time horizon. Such a long view is even more relevant when analyzing a phenomenon like climate change — experts understand how natural threats will likely develop many decades into the future, given the sophistication and accuracy of scientific climate modeling and the fact that a certain amount of warming is locked into place with current emissions. Additionally, from a security perspective, the likelihood of destabilizing threats rises as global temperatures rise. The climate risk analysis will thus be a painfully inadequate preparation for the world to come if it does not chart the security impacts of multiple warming scenarios (as the Intergovernmental Panel on Climate Change and the Center for Climate and Security’s Security Threat Assessment of Global Climate Change do), or if it ignores the potential devastation of “worst case” scenarios (see recent studies on underestimated sea level rise and ice melt). Preparing for and preventing the most disruptive risks requires including them in plans. Writing them off as unlikely gives American adversaries an uncontested field for their own long-term planning efforts.

Likewise, while examining global threats, where the experts aim their magnifying glass takes on great importance. This decade, we’ve seen how small developments like a new virus appearing in one corner of the globe can quickly affect all others. Climate risks operate on a similar level. As a recent study showed, a climate-change-associated heatwave in 2010 affected grain harvests in Russia and reverberated worldwide, ultimately contributing to price shocks in Egypt and across the Middle East in 2011. Thus, it’s crucial that the “national security” frame not limit analysis to just the United States or locations where the United States has a large footprint, such as the Indo-Pacific, Europe, or the Middle East. Most useful would be a global study broken down regionally, crafting a handy tool for American embassies and combatant commands to obtain more detail on a specific area, while also understanding the full picture of international security dynamics.

Finally, how should defense leaders undertake this analysis to create a product that stays useful into the future? Climate risk analysis should be an ongoing process for the Department of Defense. The recent establishment of the Climate Working Group, chaired by the secretary of defense, is a good step toward building longer-term capacity on these issues. This group should examine what types of tools and infrastructure are needed to institutionalize early-warning capabilities throughout the defense enterprise on climate risks. Austin and the working group should make serious efforts to ensure that climate change risk assessments become a key component of every decision-making process in the building, and that effective interagency processes are maintained to plan for and confront these risks. This includes rapidly expanding staff capacity across the department with expertise on climate and environmental issues, while ramping up training courses for leaders at all levels to get up to speed.

Unlike many risks facing the world, climate change presents us with unprecedented opportunity to assess and map the security risks to come. In fact, in comparison to the threats posed by China or extremist groups, modern climate science gives incredible abilities to understand how and where environmental shocks are most likely to strike. And while security actors are briefed daily on each new piece of intelligence on traditional threats, quality research in the climate and environmental space is not yet regularly included in security assessments. The Department of Defense’s climate risk analysis presents a unique opportunity to make climate change analysis actionable and accessible for the entire security establishment. But this is a daunting endeavor, particularly in an institution that lacks staff expertise on climate security topics and is prone to prioritizing traditional security risks.

With the Biden administration throwing its weight behind these topics, the entire national security infrastructure is now mandated to center climate risks in its work like never before. It’s crucial to get these initial efforts right, and then make fully informed, strategic investments to protect current and future generations from the risks they describe. These investments should follow a “prepare and prevent” approach aimed at minimizing the impacts of those climate risks most likely to strike today, and rapidly decarbonizing to mitigate the threats of the future. Investments to prepare include institutionalizing mechanisms across the Department of Defense, including the combatant commands, to regularly collect, interpret, and act on climate security risk information, such as warnings of drought, sea level rise, or extreme heat in already fragile states. Preparing also includes ensuring the department has invested in the right equipment and training to manage a likely increase in humanitarian relief and disaster missions, as well as operations in more extreme environments. Prevention investments are those that cut emissions — the department can lead by example in the development and deployment of clean energy technologies.

Left unchecked, climate change has the potential to unravel the very foundations of U.S. defense and security. The good news is thanks to the nature of the threat, experts know more about the effects of climate change than they could ever know about the future behavior of an adversary state like China. It’s high time the United States started preparing for and preventing these escalating threats, with the same level of seriousness given to many other looming dangers.



Kate Guy is a senior research fellow with the Center for Climate and Security, deputy director of the International Military Council on Climate and Security, and a D.Phil. candidate and lecturer in international relations at the University of Oxford.

Erin Sikorsky is deputy director of the Center for Climate and Security, and the director of the International Military Council on Climate and Security. Previously, she served as the deputy director of the Strategic Futures Group on the National Intelligence Council in the United States, where she co-authored the quadrennial Global Trends report and led the U.S. intelligence community’s environmental and climate security analysis.

 Image: 1st Lt. Zachary West