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: 33.61). 09/2013; 341(6151):1235367. DOI: 10.1126/science.1235367
Source: PubMed


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,
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    • "The dominant view in the existing literature is that economic conditions are the main determinants of civil wars and conflicts in less developed countries (Collier and Hoeffler, 1998; Elbadawi and Sambanis, 2000, 2002; Goldstone et al., 2010). In addition, recent studies have explored the role of ethnic (Easterly and Levine, 1997; Elbadawi and Sambanis, 2002; Posner, 2004) and climatic (Miguel et al., 2004; Burke et al., 2009; O'Loughlin et al., 2012; Scheffran et al., 2012; Hsiang et al., 2013) variables as potential explanatory factors of the high incidence of civil wars in SSA. However, most of these studies have used the frequency/intensity of civil conflicts or wars as response variables. "
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    ABSTRACT: There is a growing interest and concern for understanding the interaction among human population growth and the sustainability of natural resources. In fact, many agrarian societies experienced an increasing frequency of wars, famines and epidemics during the periods of resource depletion. People from Sub-Saharan Africa (SSA) have suffered the demographic consequences of famines, civil wars and political instabilities during the last 50 years. Almost half of the countries of SSA have undergone some form of demographic crisis over the past 50 years. Our analysis indicate that despite that environmental conditions were positively correlated with crop production across SSA, Malthusian factors correlated inversely with cultivation intensity, which in turn translated into a higher magnitude of depopulation suffered during the past 50 years. In this paper, we provide empirical evidence that population collapses in SSA during the last 50 years have been multifactorial, although more closely associated with “Malthusian” factors as proximal drivers. Other proximal drivers such as economic indicators, political stability and environmental determinants did not explain as much variance as Malthusian forces, suggesting that explanations of collapse magnitude in SSA are embedded in a complex multi-causal chain, in which demographic factors may play a modulating role yet to be explored in more depth.
    11/2015; 3(20). DOI:10.3389/fevo.2015.00130
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    • "Le Billon, 2001); or that capacities for conflict resolution and mitigation have been increasing overall (Gleditsch, 1998; Diehl and Gleditsch, 2000; Barnett, 2000). As a result, the climate–conflict link remains controversial (Bernauer et al., 2012; Buhaug et al., 2014; Theisen et al., 2013; Scheffran et al., 2012a, 2012b; Hsiang et al., 2013). Irrespective of their scientific foundations or actual impact, however, the security implications of climate change have been addressed by political institutions, as well as in political discourse and political rhetoric (Brzoska and Oels, 2011; Oels, 2012; Methmann and Rothe, 2012). "
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    ABSTRACT: Security implications of climate change have been highlighted by various political and advisory bodies, as well as non-governmental organizations (NGOs), in recent years. It is unclear, however, whether such a ‘securitization’ of climate change can also be found beyond institutionalized politics in the public realm, and beyond Western countries. This article addresses these questions by investigating mass media coverage in nine countries over a period of 15 years. Based on an analysis of more than 101,000 newspaper articles, it shows an increasing discussion of climate change in security terms, with diverging trends in the analysed countries. While Western, industrialized countries such as the USA, the UK or Australia display an increasing securitization of climate change, the amount of securitizing language has decreased in India and South Africa. Moreover, different countries refer to different security dimensions – with regard both to the subjects whose security is of concern (national security, human security) and to the type of resources that are discussed in security terms (energy security, water security, food security). While Western countries strongly focus on national security and energy security, emerging economies place greater emphasis on food and, less pronounced, on water security.
    Security Dialogue 10/2015; DOI:10.1177/0967010615600915 · 1.36 Impact Factor
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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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