Stanford University

Video credit: Devon Ryan

Does climate change cause armed conflict?

As global temperatures climb, the risk of armed conflict is expected to increase substantially, according to experts across several fields. Extreme weather and related disasters can damage economies, lower farming production and intensify inequality.

BY Devon Ryan, Woods Institute for the Environment
ClockJune 12, 2019

Intensifying climate change will increase the future risk of violent armed conflict within countries, according to a study published today in the journal Nature. Synthesizing views across experts, the study estimates climate has influenced between 3% and 20% of armed conflict risk over the last century and that the influence will likely increase dramatically.

Man pouring water into plastic containers
Fari Awade draws water from a well in the community of Natriguel, Mauritania. Climate-related hazards, such as droughts, can cause economic shocks to agricultural communities, which may heighten the risk of armed conflict, according to a new Stanford-led study. (Photo credit: Pablo Tosco/Oxfam)

In a scenario with 4 degrees Celsius of warming (approximately the path we’re on if societies do not substantially reduce emissions of heat-trapping gases), the influence of climate on conflicts would increase more than five times, leaping to a 26% chance of a substantial increase in conflict risk, according to the study. Even in a scenario of 2 degrees Celsius of warming beyond preindustrial levels – the stated goal of the Paris Climate Agreement­ – the influence of climate on conflicts would more than double, rising to a 13% chance.

“Appreciating the role of climate change and its security impacts is important not only for understanding the social costs of our continuing heat-trapping emissions, but for prioritizing responses, which could include aid and cooperation,” said Katharine Mach, director of the Stanford Environment Assessment Facility and the study’s lead author.

Climate change-driven extreme weather and related disasters can damage economies, lower farming and livestock production and intensify inequality among social groups. These factors, when combined with other drivers of conflict, may increase risks of violence.

“Knowing whether environmental or climatic changes are important for explaining conflict has implications for what we can do to reduce the likelihood of future conflict, as well as for how to make well-informed decisions about how aggressively we should mitigate future climate change,” said Marshall Burke, assistant professor of Earth system science and a co-author on the study.

Planning ahead

Reducing conflict risk and preparing for a changing climate can be a win–win approach. The study explains that adaptation strategies, such as crop insurance, post-harvest storage, training services and other measures, can increase food security and diversify economic opportunities, thereby reducing potential climate–conflict linkages. Peacekeeping, conflict mediation and post-conflict aid operations could incorporate climate into their risk reduction strategies by looking at ways climatic hazards may exacerbate violent conflict in the future.

However, the researchers make clear there is a need to increase understanding of these strategies’ effectiveness and potential for adverse side effects. For example, food export bans following crop failures can increase instability elsewhere.

“Understanding the multifaceted ways that climate may interact with known drivers of conflict is really critical for putting investments in the right place,“ Mach said.

Mach is also a senior research scientist in Earth system science. Burke is a center fellow at the Freeman Spogli Institute for International Studies and, by courtesy, at the Stanford Woods Institute for the Environment. Fearon is the Theodore and Frances Geballe Professor in the School of Humanities and Sciences and a senior fellow at the Freeman Spogli Institute for International Studies.

Other Stanford co-authors include: Chris Field, the Melvin and Joan Lane professor for Interdisciplinary Environmental Studies, a professor of biology and of Earth system science, Perry L. McCarty director of the Stanford Woods Institute for the Environment, and a senior fellow at the Precourt Institute for Energy; Kenneth Schultz, professor of political science; and Caroline Kraan, research professional at the Stanford Woods Institute for the Environment and the Stanford Environment Assessment Facility. Other co-authors include researchers from the University of Exeter, the Peace Research Institute Oslo, the Norwegian University of Science and Technology, the National Bureau of Economic Research, the University of Denver, the University of Antwerp, Lancaster University, the University of Colorado Boulder, the College of William & Mary, the University of Hamburg and Uppsala University.

The research was supported by the Alexander von Humboldt Foundation, the Stanford Woods Institute for the Environment, the European Research Council, the German Science Foundation and the Swedish Foundation for Strategic Environmental Research.

Media Contacts

Katharine Mach

Department of Earth System Science

(650) 561-5640,

Devon Ryan

Stanford Woods Institute for the Environment

(650) 497-0444,

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