Climate and Conflict: Why Politicians Should Understand How Climate Change Poses a Threat to Security

In a speech given in November 2015 at Old Dominion University, Secretary of State John Kerry described climate change as a threat not only to the security of the United States but also to the security and stability of countries everywhere.

While the general public often perceives the negative effects of climate change as truly threatening but somewhat far off in the future, there is scientific evidence proving that impacts from climate change are already occurring. As summarized in a recent NBER Working Paper by Marshall Burke, Solomon M. Hsiang, and Edward Miguel, deviations from moderate climate and precipitation patterns systematically increase the risk of violence and conflict.

The authors review 55 papers regarding the relationship between conflict and climate change. They conclude that changes in climate conditions, such as temperature, rainfall, and water availability, influence the conditions under which certain social interactions occur, in both the short and long term, and thus may impact the probability and intensity of conflicts. The study finds that these results hold across geographic regions, different societies, and over time.

The increased risk is observed for two categories of conflict: first, for interpersonal conflicts occurring between individuals, such as assault, murder, rape, road rage, or violence at sporting events or by the police; and, second, for intergroup conflicts, describing conflicts between groups of individuals, such as organized political violence, civil conflicts, riots, or land invasion.

Experimental studies and crime statistics show that individuals are more likely to behave violently during days when temperatures are higher, as summarized in studies from Australia, India, Mexico, the Philippines, Tanzania, and the United States. These findings are more significant in low-income settings and in economies that are dependent on agriculture, but they are also statistically significant in wealthy nations.

For intergroup conflicts, the results show that anomalously cold and warm temperatures lead to an increase in violence: During colder epochs, anomalously cold events are linked with higher conflict rates such as political instability in dynastic China and inter-ethnic violence in feudal Europe. During warmer times—like in most modern societies—anomalously hot events elevate the risks of different forms of intergroup conflict such as gang violence in the United States or land invasion in Brazil and Indonesia.

What are the causal relationships behind these findings? It seems natural that economic factors play an important role. As one example, in low-income societies that are highly dependent on agriculture, economic conditions—and, as a result, the livelihood of citizens—are directly influenced by extremes such as droughts, heavy rainfalls, and storms. In addition, population density can play a role in cases where climatic events induce migration from rural areas into urban centers. In the short run, labor markets are unable to fully absorb this migration. Some articles also suggest that an aggressor’s chances of being successful increase due to climatic events, e.g. if the incumbent government is weakened due to having fewer economic resources (via taxes) to distribute, or if high rainfall and floods prevent military troops from reaching areas of violence (there are several examples of this in East Africa).

Finally, psychological aspects may be similarly important. The significant increase of short-run crime rates in wealthy societies during temporary high temperature times—independent of any economic conditions— suggests that weather extremes allow relatively small disputes between individuals to more easily escalate into serious confrontations. Although research is still limited in this field, the most robust evidence currently refers to serotonin, a neurotransmitter that facilitates body temperature regulation and is associated with aggressive behavior.

As the authors aim to identify reliable, common results among the different studies under review, they implement a meta-study, whereby they take into account differences between the studies in average temperatures, precipitation levels, and general living conditions in each society.

This meta-study shows that, across all studies, a one-unit deviation from present average temperature is observed with an 11.3 percent increase in the frequency of political conflict between groups of people, as well as a 2.4 percent increase in violence between individuals. In addition, for a one-unit deviation in average rainfall during two harvest periods in a row (cumulative effect), the researchers find a 3.5 percent increase in the likelihood of intergroup conflicts (civil riots, land invasion, etc.).

Although correlation does not necessarily imply causation in the arena of weather events and violence within communities, more research should be conducted to investigate the complex relationships between climate patterns and various aspects of economic conditions, society, and human behavior. For policymakers aiming for a reduction in conflict levels, it is crucially important to acknowledge the existing evidence for the relationship between climate and conflict and to better understand the mechanisms by which climate patterns may influence the likelihood of conflicts. Only then can policies aimed at reducing the risk of conflict be most effective, both on the large-scale level of political conflicts and on the small-scale level of conflicts between individuals.

At the same time, further research must be done on whether, when, and how societies are able to adapt to climate change, thereby being able to reduce the negative impact of changes in long-term climate patterns on conflict risks. The few existing studies on climate adaptation, however, suggest that long-term adaptation has not yet occurred to a large extent.

Considering the significant effects of current climate on conflict risk, it seems that a substantial level of adaptation is needed to offset increased conflict risk due to climate extremes.

Article Source: Burke, Marshall, Solomon M Hsiang, and Edward Miguel. “Climate and Conflict.” National Bureau of Economic Research, 2014.

Featured Photo: cc/(Climate Change, Agriculture, and Food Security)