My latest book—States and Nature: The Effects of Climate Change on Security (Cambridge University Press)—has been more than two decades in the making. And as I reflect on that journey, I see significant parallels between my own trajectory and the larger efforts to define and refine thinking about climate security.

It was nearly twenty years ago when the Wilson Center provided me with my first platform on climate and security in a short paper co-authored with former climate diplomat Nigel Purvis. We wrote about the implications of climate change for international peace and security and the UN system, at a time when the empirical literature on climate and security was scant.

We concluded our paper with these words:

Climate change will trigger profound global change, and these changes could pose genuine risks to international peace and security. Managing these changes well will require well-conceived actions within the UN system. While climate change could contribute to armed conflict and violence, that is not the primary risk. Preventing large-scale humanitarian catastrophes from climate-related droughts, floods, crop failures, mass migrations, and exceptionally severe weather remains the most significant policy challenge.

These conclusions hold up pretty well, as does the emphasis on the kinds of states most vulnerable to the security implications of climate change, namely least developed nations, weak states, and undemocratic countries.

So how did my own trajectory since that moment lead to a deeper engagement with this emergent field?

A Scholarly Detour  

That 2004 paper led to an unexpected professional turn. Up until that point, I was mostly a scholar of transnational advocacy movements. The successes and failures of such movements  were the subject of my first and second books. Writing the paper for the Wilson Center would ultimately make climate and security the subject of this my third book for Cambridge.

A postdoctoral fellowship in the international security program at Harvard’s Belfer Center was one catalyst to deepen my interest. While there, I wrote a scholarly paper on the national security implications of climate change for the United States that was ultimately published in Security Studies. An offshoot of that project was a 2007 report for the Council on Foreign Relations, one of the early think tank papers on climate and security.

Emergent policy interest in climate security really kicked off in 2007, with my paper for the Council on Foreign Relations and a landmark report from CNA among others. Led by former Deputy Undersecretary of Defense Sherri Goodman, the CNA report introduced the concept of climate change as a “threat multiplier” that combines with other sources of risk to make matters worse.

An empirical academic literature developed alongside the policy debate. Much of it was quantitative and tried to assess whether proxies for climate change were associated with armed conflict. The evidence was nuanced and contested, with debates often coming down to model specification, choice of datasets, and other arcana.

Why This Book

When I first started conceptualizing States and Nature in 2012 or 2013, there were few if any scholarly books on climate and security. In particular, I noticed that the field still lacked an adequate understanding of causal mechanisms that linked climate to negative security outcomes.

That phrasing negative security outcomes is deliberate. Scholars have taken a largely narrow view of security problems in terms of violent conflict, while practitioners care about wider effects such as humanitarian emergencies that threaten large numbers of lives and often compel military mobilizations.

Writing a book meant I could offer more granularity on the causal pathways connecting climate changes to these negative security outcomes, including (but not limited to) conflict. I could also encompass what Morgan Bazilian and Cullen Hendrix have called “actorless threats” like climate change and pandemics—whose effects are so severe they constitute security problems despite lacking human agents deliberately trying to harm others.

I also sought to address a long-standing methodological critique of the academic literature on environmental security. In the 1990s, Thomas Homer-Dixon and his collaborators pioneered qualitative case studies, mostly of single country cases that traced connections between environmental change and violent conflict. But Marc Levy offered an important critique of that literature on methodological grounds in International Security, writing:

The more logical research strategy under the circumstances would be to compare societies facing similar environmental problems but exhibiting different levels of violent conflict. That would permit some precision in identifying the conditions under which environmental degradation generates violent conflict and when it does not, and for formulating useful policy advice on how to avoid violent outcomes.

My own project envisioned taking Levy up on that challenge. I wanted to write a book that would provide some visibility on that question, and offer both academics and policymakers tools to identify countries they should most be worried about—and possible entry points for preventive action.

In seeking paired cases, I aimed for geographic breadth and found suitable, albeit imperfect, cases in Africa, the Middle East, and South Asia. Why did Somalia have a famine after drought but almost no one died in neighboring Ethiopia after similar drought exposure? Why did Syria experience a civil war after a severe drought but neighboring Lebanon did not? Why did large numbers of people die in Myanmar after a severe cyclone but very few people died in Bangladesh and India after similar exposure to very severe cyclones?

Capacity, Inclusion, and International Assistance

My reading of these cases and wider literature helped me identify the most likely cases for negative security outcomes after exposure to climate hazards. These states shared three traits: (1) limited government capacity to deliver services, (2) exclusive political institutions that provide services to some groups and not others, and (3) foreign assistance is blocked or delivered in a one-sided manner.

Weak capacity states have limited ability to prepare for or respond to climate threats. Exclusive political institutions limit representation of all social groups in government, leaving some groups at the mercy of climate exposure. And while foreign assistance, including overseas development aid, humanitarian assistance, and diaspora resources can compensate for weak state capacity, such aid is often blocked, either because states are pariahs in the international system and/or because groups in those countries actively shun international help.

My book traces how these countries have faced similar exposure to climate-related hazards that led (or could have led) to large-scale loss of life or major disruptions in livelihoods. I show how well-prepared states with capacity and more inclusive institutions that made judicious use of foreign assistance (namely Ethiopia, Lebanon, Bangladesh/India in my research) were able to ward off the worst security consequences after exposure to climate hazards. Other states—Somalia, Syria, and Myanmar—had worse outcomes. Their state institutions were incapable of service delivery in the lead-up to and in the wake of climate exposure, and exclusive political institutions did not consider or respond to the needs of all social groups. And, aid was blocked or delivered to some groups, and not to others.

The case studies also allowed me to compare countries to themselves over time. In the 1980s, Ethiopia experienced a devastating drought which led to a world-publicized famine that killed hundreds of thousands. (This crisis motivated the fundraising and awareness raising effort of the Live Aid concert in 1985.) By 2015, Ethiopia would face a severe drought but almost no one died because its state capacity, inclusion, and ability to tap foreign assistance all improved in the interim. Bangladesh and India also experienced similar improvements over time.

The Meaning for Policy

As I write in States and Nature, these experiences of these nations suggest promise and peril for policy. Focused efforts to address drought and food security risks in Ethiopia led to dramatic improvements. International assistance was critical in helping Ethiopia build such a safety net. Bangladesh was also able to tap international assistance to address the risks of severe cyclones through early warning systems, cyclone shelters, and other improvements. Such preventive efforts offer clues of what robust adaptation to climate change might look like in coming decades.

Yet there is reason for caution. State capacity and political inclusion are not static qualities, nor is history directional towards better outcomes. Without vigilance and far-sighted leadership, progress can be undone, as Ethiopia’s on-going civil war attests. Institutional capacity to deliver services can decay, and leaders may pursue or be driven to support divisive strategies that end in tears and tragedy.

Indeed, the ability of narrow technical solutions to improve state capacity in discrete areas like food security and cyclone preparedness hinge crucially on local leaders willing to pursue broadly inclusive social policies. While democracies tend to be better at social inclusion, Ethiopia provides an example of an inclusive authoritarian regime.

The challenge for outside actors is that they may face limited leverage to build inclusive governments without local support. That can lead to awful choices of delivering aid to countries that might reward some groups over others—or not deliver aid at all. This may leave entire societies at risk to food and water shortages, livelihood shocks, and contestation over resources.

The Climate Security Risks Ahead of Us

Global disaster risk reduction world provides a hopeful sign. Optimists tout that despite large and increasing numbers of people living in harm’s way to climate-related hazards, fewer people die. They argue that better building codes, early warning, pre-positioning of aid, and other measures prevent large-scale loss of life.

But scientists warn that such optimism may be misplaced in a world where climate change deviates increasingly from known human experience. What if the new normal in places like the southwestern United States is perennial droughts, high temperatures, reduced snowpack, and year-round wildfires. What if more places around the world face temperature extremes that radically diminish prospects for farming and fresh water—and render them virtually uninhabitable?

We see glimpses of that world every day in the news, with weather extremes that surprise long-time observers and deepen climate professionals’ dismay and public anxiety. These warning signs suggest that we cannot adapt our way out of this problem, underscoring the urgency of the clean energy transition and dramatic efforts to reduce emissions of greenhouse pollutants.

Even as the transition to renewables and electric vehicles beckons (introducing its own set of security challenges), the clean energy transition itself will be dangerous and difficult as countries try to wean themselves off of legacy fossil fuels. Understanding the geostrategic implications of that transition is my next project.

In the meantime, I hope that States and Nature provides readers with an understanding of how we got to this moment in the study and practice of climate security—as well as some provisional ways forward.