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: 31.48). 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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Available from: Solomon M Hsiang, Aug 30, 2015
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    • "Most studies have focused on the link between climate and conflict (Miguel et al. 2004; Hsiang et al. 2013). While some dispute the evidence linking weather to conflict (Klomp & Bulte, 2013), most find support for the existence of a causal relation, especially in low-income settings (Hsiang et al. 2013). However, the literature is divided about the nature of the weather-conflict relationship, and the mechanisms that explain the link (Buhaug 2010; Klomp & Bulte 2013). "
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    DESCRIPTION: A rapidly growing body of research examines how weather variability, anomalies and shocks influence economic and societal outcomes. This study investigates the effects of weather shocks on African smallholder farmers in British colonial Africa and intervenes in the debate on the mediating effect of cash crops on resilience to shocks. We employ a dual research strategy, involving both qualitative and econometric analysis. We analyse original primary evidence retrieved from annual administrative records and construct a panel dataset of 151 districts across West, South-central and East Africa in the Interwar Era (1920-1939). Our findings are twofold. First, we qualitatively expose a range of mechanisms leading from drought and excessive rainfall to harvest failure, social tension and distress. We then test the link econometrically and find a robust and significant U-shaped relation between rainfall deviation and social tension and distress, proxied by annual imprisonment. Second, we review a long-standing and unsettled debate on the impact of cash crop cultivation on smallholders’ resilience to climatic shocks and find that cash crop districts experienced lower levels of social tension and distress in years of anomalous rainfall.
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    • "Highly publicized studies in general science journals like Nature ( Hsiang et al . , 2011 ) , Science ( Hsiang et al . , 2013 ) , Climatic Change ( Wischnath and Buhaug , 2014 ; Tol and Wagner , 2010 ) , and Proceedings of the National Academy of Science ( Burke et al . , 2009 ; Buhaug , 2010 ; O ' Loughlin et al . , 2012 , 2014a , b ) have investigated the associations between climate anomalies and violence . Some findings in this body of research have been d"
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    ABSTRACT: In the debate about possible linkages between global environmental change and violent conflict, the research is overwhelmingly based on analysis of aggregate data for administrative areas, towns or villages, and geographic grids. With some exceptions, researchers rarely examine social and political processes that might link climate anomalies and violence experiences at the scale of individuals or households. We remedy this shortcoming by analyzing survey data for 504 Kenyans living in three counties collected in November 2013. We probe respondents’ attitudes concerning perceived precipitation irregularities and their beliefs and economic activities. We find that in areas with reported worsening drought conditions, inter-community dialogue between ethnic groups has a pacifying conditional influence on support for the use of violence. The presence of local official rules regulating natural resource use consistently has no effect on beliefs about using violence where droughts are reported. To reduce possible bias in the reporting of drought conditions, our statistical models are estimated with controls for changes in measured vegetation health over time in survey sample areas. The moderating effect of inter-community dialogue on attitudes about violence under circumstances of environmental stress points to the importance of social and political contexts in studying connections between environmental change and conflict.
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    • ". A rapidly expanding set of scientific studies has examined the historical data and shown that climate stress is very strongly statistically associated with political violence and instability (Hsiang et al 2013). 2. The climate stresses that historically have elevated security risks are manifesting with higher frequency, higher magnitudes, and even in new alarming forms (McElroy and Baker 2012). "
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    ABSTRACT: DHS should continue to incorporate climate change into its risk framework. The reasons are simple: climate change is endangering Americans and disrupting our economy, and It threatens to destabilize regions of high national interest. In this light, what the 2014 Quadrennial Homeland Security Review says about climate change is actually far too tame. Our knowledge of the threat is growing, the risks are rising, and government responses are weak and uncoordinated. Someone should be ringing alarm bells.
    Hearing on “Examining DHS’s Misplaced Focus on Climate Change”, Washington, DC; 07/2015
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