Beyond climate and conflict relationships: New evidence from a Copula-based analysis on an historical perspective

This paper contributes to the new climate-society literature (Carleton and Hsiang, 2016) by analyzing the role of climate in conflicts over the pre-industrial period in Europe, in the vein of the recent literature initiated by Tol and Wagner (2010) and Burke and Hsiang (2014). As far as we know, this study is the first to apply a (time-varying) copula analysis to climate-economics literature and to investigate the dependence between climate and conflicts in a historical time series context. Both social disturbances and wars are considered and their interrelationships are taken into account. The main contributions of the paper are: (1) the use of copula analysis compared to previous correlational approaches; (2) the analysis of the temporal heterogeneity of climatic effects via a time varying approach; (3) the introduction of agricultural and fiscal pressure channels to investigate the interrelationships between climate, social disorders and warfare; (4) the investigation of El Niño Southern Oscillation (ENSO) and North Atlantic Oscillation (NAO) Teleconnections effects whereas previous long-term historical studies have only focused on precipitation and temperature data. Time varying Copula analysis enabled us to identify a positive dependence between temperatures and conflicts, and negative or positive dependences between anomalous precipitation and conflicts, by explicitly focusing on the joint distribution of our variables. We were also able to precisely identify the periods/regimes during which the link between climate and conflict was genuinely active and then stress on the agricultural and fiscal revenues channels.