Certain regions of the world experience more conflict than others+ Previous analyses have shown that a civil war in one country significantly increases the likelihood that neighboring states will experience conflict+ This finding, however, still remains largely unexplained+ We argue that population movements are an important mechanism by which conflict spreads across regions+ Refugee flows are not only the consequence of political turmoil-the presence of refugees and displaced populations can also increase the risk of subsequent conflict in host and origin countries+ Refugees expand rebel social networks and constitute a negative externality of civil war+ Although the vast majority of refugees never directly engage in violence, refugee flows may facilitate the transnational spread of arms, combatants, and ideologies conducive to conflict; they alter the ethnic composition of the state; and they can exacerbate economic competition+ We conduct an empirical analysis of the link between refugees and civil conflict since the mid-twentieth century, and we find that the presence of refugees from neighboring countries leads to an increased probability of violence, suggesting that refugees are one important source of conflict diffusion+ Certain regions of the world experience more conflict than others+ Regions such as Central America, the Great Lakes region of Africa, and SouthEast Asia have witnessed numerous civil wars within several states, whereas other areas such as Europe and the Southern Cone of Latin America have had a relatively low frequency of internal conflict+ Statistical analyses, moreover, have demonstrated that there is a regional clustering of civil war and that states bordering countries at war

Much of the debate over the security implications of climate change revolves around whether changing weather patterns will lead to future conflict. This article addresses whether deviations from normal rainfall patterns affect the propensity for individuals and groups to engage in disruptive activities such as demonstrations, riots, strikes, communal conflict, and anti-government violence. In contrast to much of the environmental security literature, it uses a much broader definition of conflict that includes, but is not limited to, organized rebellion. Using a new database of over 6,000 instances of social conflict over 20 years – the Social Conflict in Africa Database (SCAD) – it examines the effect of deviations from normal rainfall patterns on various types of conflict. The results indicate that rainfall variability has a significant effect on both large-scale and smaller-scale instances of political conflict. Rainfall correlates with civil war and insurgency, although wetter years are more likely to suffer from violent events. Extreme deviations in rainfall – particularly dry and wet years – are associated positively with all types of political conflict, though the relationship is strongest with respect to violent events, which are more responsive to abundant than scarce rainfall. By looking at a broader spectrum of social conflict, rather than limiting the analysis to civil war, we demonstrate a robust relationship between environmental shocks and unrest.

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Many rebel organizations receive significant assistance from external governments, yet the reasons why some rebels attract foreign support while others do not is poorly understood+ We analyze factors determining external support for insurgent groups from a principal-agent perspective+ We focus on both the supply side, that is, when states are willing to support insurgent groups in other states, and the demand side, that is, when groups are willing to accept such support, with the conditions that this may entail+ We test our hypotheses using new disaggregated data on insurgent groups and foreign support+ Our results indicate that external rebel support is influenced by characteristics of the rebel group as well as linkages between rebel groups and actors in other countries+ More specifically, we find that external support is more likely for moderately strong groups where support is more likely to be offered and accepted, in the presence of transnational constituencies, international rivalries, and when the government receives foreign support+

This paper introduces the Non-State Actors in Armed Conflict Dataset (NSA), which contains detailed information on the state–rebel group dyads included in the Uppsala Conflict Data Project Dyadic Dataset. Existing quantitative studies generally focus on characteristics of countries and conflicts to examine the duration, severity, outcome and recurrence of civil wars, in ways that often ignore the actors in civil wars. The NSA data provides additional information on the organizations involved in conflict dynamics. We describe the structure of the NSA data and the variables included, provide descriptive statistics of the indicators, and discuss areas for future research on non-state actors to enhance our understanding of conflict processes.