We examine how Syria’s local growing seasons and precipitation variability affected patterns of violence during the country’s civil war (2011–19). Among Syria’s 272 subdistricts (nahiyah), we study conflict events initiated by the Assad regime or its allies, and, separately, by other armed non-government groups (‘rebels’). Throughout the war, violence to capture agriculture has been used regularly to control valuable cropland and harvests. Combatants also seek to deny their adversaries access to these resources by deploying violence to destroy agriculture. We test the hypothesis that conflict was most likely during local growing seasons due to both of these motivations. Additionally, we examine whether unusually dry conditions further elevated the risk of conflict during growing season months. A theory for why higher levels of conflict would occur during unusually dry conditions is that livelihood losses elevate incentives to control scarce crops and also facilitate recruitment of militants or their sympathizers. We find that violent events initiated by the government and rebel groups are both more likely during the growing season than other times of the year. There is also evidence that dry conditions during the growing season led to an increase in government-initiated attacks over the duration of the war. We find the strongest relationship between precipitation deficits and both government- and rebel-initiated violence in later years of the war. Compared with our growing season results, the rainfall deviation estimates are less consistent across models.

我们研究了叙利亚的本地生长期和降雨多变性如何影响该国内战期间（2011-19年）的暴力行为。在叙利亚的272个街道（nahiyah），我们研究由阿萨德政权或其盟国发起的冲突事件，并单独通过其他武装非政府团体（“叛乱分子”）。在整个战争中，经常使用暴力夺取农业来控制宝贵的耕地和收成。战斗人员还试图通过部署暴力摧毁农业来拒绝对手使用这些资源。我们检验了以下假设：由于这两种动机，冲突在当地生长期最有可能发生。此外，我们检查了生长季节月份中异常干燥的条件是否进一步增加了发生冲突的风险。关于为什么在异常干旱的情况下会发生更高程度的冲突的理论是，生计的丧失会提高控制稀缺作物的动机，也有助于招募激进分子或其同情者。我们发现，由政府和叛乱团体发起的暴力事件在生长期都比一年中的其他时间更有可能发生。也有证据表明，生长季节期间的干旱条件导致战争期间政府发起的袭击有所增加。我们发现，在战争后期，降水不足与政府和叛乱分子引发的暴力之间存在最密切的关系。与我们的生长季节结果相比，各模型的降雨偏差估算值不一致。