No abstract

Recent studies concerning the possible relationship between climate trends and the risks of violent conflict have yielded contradictory results, partly because of choices of conflict measures and modeling design. In this study, we examine climate-conflict relationships using a geographically disaggregated approach. We consider the effects of climate change to be both local and national in character, and we use a conflict database that contains 16,359 individual geolocated violent events for East Africa from 1990 to 2009. Unlike previous studies that relied exclusively on political and economic controls, we analyze the many geographical factors that have been shown to be important in understanding the distribution and causes of violence while also considering yearly and country fixed effects. For our main climate indicators at gridded 1°resolution (∼100 km), wetter deviations from the precipitation norms decrease the risk of violence, whereas drier and normal periods show no effects. The relationship between temperature and conflict shows that much warmer than normal temperatures raise the risk of violence, whereas average and cooler temperatures have no effect. These precipitation and temperature effects are statistically significant but have modest influence in terms of predictive power in a model with political, economic, and physical geographic predictors. Large variations in the climate-conflict relationships are evident between the nine countries of the study region and across time periods.social instability | standard precipitation index | generalized additive modeling | negative binomial modeling | disaggregated spatial analysis

We examine the relationship between the temporal and spatial aspects of democratic diffusion in the world system since 1946. We find strong and consistent evidence of temporal clustering of democratic and autocratic trends, as well as strong spatial association (or autocorrelation) of democratization. The analysis uses an exploratory data approach in a longitudinal framework to understand global and regional trends in changes in authority structures. Our work reveals discrete changes in regimes that run counter to the dominant aggregate trends of democratic waves or sequences, demonstrating how the ebb and flow of democracy varies among the world's regions. We conclude that further analysis of the process of regime change from autocracy to democracy, as well as reversals, should start from a "domain-specific" position that dis-aggregates the globe into its regional mosaics.

A recent Climatic Change review article reports a remarkable convergence of scientific evidence for a link between climatic events and violent intergroup conflict, thus departing markedly from other contemporary assessments of the empirical literature. This commentary revisits the review in order to understand the discrepancy. We believe the origins of the disagreement can be traced back to the review article's underlying quantitative meta-analysis,