Infrastructure built to protect cities from flooding can increase economic damages elsewhere.
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Edited by B. L. Turner, Arizona State University, Tempe, AZ, and approved October 9, 2014 (received for review June 24, 2014)
Significance
A robust debate about the effects of climate change on conflict occurrences has attained wide public and policy attention, with sub-Saharan Africa generally viewed as most susceptible to increased conflict risk. Using a new disaggregated dataset of violence and climate anomaly measures (temperature and precipitation variations from normal) for sub-Saharan Africa 1980–2012, we consider political, economic, and geographic factors, not only climate metrics, in assessing the chances of increased violence. The location and timing of violence are influenced less by climate anomalies than by key political, economic, and geographic factors. Overall, the temperature effect is statistically significant, but important inconsistencies in the relationship between temperature extremes and conflict are evident in more nuanced relationships than have been previously identified.
Abstract
Ongoing debates in the academic community and in the public policy arena continue without clear resolution about the significance of global climate change for the risk of increased conflict. Sub-Saharan Africa is generally agreed to be the region most vulnerable to such climate impacts. Using a large database of conflict events and detailed climatological data covering the period 1980–2012, we apply a multilevel modeling technique that allows for a more nuanced understanding of a climate–conflict link than has been seen heretofore. In the aggregate, high temperature extremes are associated with more conflict; however, different types of conflict and different subregions do not show consistent relationship with temperature deviations. Precipitation deviations, both high and low, are generally not significant. The location and timing of violence are influenced less by climate anomalies (temperature or precipitation variations from normal) than by key political, economic, and geographic factors. We find important distinctions in the relationship between temperature extremes and conflict by using multiple methods of analysis and by exploiting our time-series cross-sectional dataset for disaggregated analyses.
- climate variability
- multilevel modeling
- disaggregated spatial analysis
- regional contexts
- types of violence indicators
Footnotes
- ↵1To whom correspondence may be addressed. Email: johno{at}colorado.edu.
Author contributions: J.O., A.M.L., and F.D.W.W. designed research; A.M.L. and F.D.W.W. analyzed data; and J.O., A.M.L., and F.D.W.W. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
Data deposition: Data and R replication code are available at www.colorado.edu/ibs/climateconflict/PNAS_SSA/.
This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1411899111/-/DCSupplemental.
Freely available online through the PNAS open access option.
Temperature, precipitation, and violence in Africa
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