Quantifying the influence of climate on human conflict.

Program in Science, Technology and Environmental Policy, Woodrow Wilson School of Public and International Affairs, Princeton University, Princeton, NJ 08544, USA.
Science (Impact Factor: 31.2). 09/2013; 341(6151):1235367. DOI: 10.1126/science.1235367
Source: PubMed

ABSTRACT A rapidly growing body of research examines whether human conflict can be affected by climatic changes. Drawing from archaeology, criminology, economics, geography, history, political science, and psychology, we assemble and analyze the 60 most rigorous quantitative studies and document, for the first time, a striking convergence of results. We find strong causal evidence linking climatic events to human conflict across a range of spatial and temporal scales and across all major regions of the world. The magnitude of climate's influence is substantial: for each one standard deviation (1σ) change in climate toward warmer temperatures or more extreme rainfall, median estimates indicate that the frequency of interpersonal violence rises 4% and the frequency of intergroup conflict rises 14%. Because locations throughout the inhabited world are expected to warm 2σ to 4σ by 2050, amplified rates of human conflict could represent a large and critical impact of anthropogenic climate change.

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    Journal of Economic Geography 09/2014; · 3.26 Impact Factor
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    ABSTRACT: Last year, a meta-analysis published in Science by Hsiang, Burke, and Miguel (HBM) argued that climate is robustly and causally related to many forms of conflict. A commentary article by Buhaug et al. questioned the assumptions and sample selection strategy underlying this analysis, and showed that these decisions had a dramatic impact on their conclusion. In a reply to the commentary, HBM dismiss these concerns and instead claim that Buhaug et al. committed five key errors in their own analysis. We assess these claims and find that they largely miss the target. HBM are correct in pointing to a minor coding error and we also agree with HBM that Buhaug et al. could have been clearer in explaining some of their proposed modifications. Those issues notwithstanding, we argue that Buhaug et al.’s concerns about the viability of the fixed effect-based meta-analysis presented in Hsiang et al. remain valid.
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    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 relation-ship between temperature extremes and conflict by using multiple methods of analysis and by exploiting our time-series cross-sectional dataset for disaggregated analyses.
    Proceedings of the National Academy of Sciences 11/2014; · 9.81 Impact Factor


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May 30, 2014