Does foreign military assistance strengthen or further weaken fragile states facing internal conflict? Aid may strengthen the state by bolstering its repressive capacity vis-à-vis armed nonstate actors or weaken it if resources are diverted to these very groups. We examine how US military aid affects political violence in Colombia. . . 
Oeindrila Dube, New York University / Suresh Naidu, Columbia University

An interesting stream of the civil conflict literature has identified an important subset of civil conflicts with disastrous consequences, that is, those that emerge as a consequence of shocks to renewable natural resources like land and water. This literature is, however, reliant on qualitative case studies when claiming a causal relationship leading from renewable resource shocks to conflict. In this article, we seek to advance the literature by drawing out the implications of a well-known formal model of the renewable resources–conflict relationship and then conducting rigorous statistical tests of its implications in the case of a serious ongoing civil conflict in India. We find that a one standard deviation decrease in our measure of renewable resources increases killings by nearly 60 percent over the long run . . . 
Shanker Satyanath, Kishore Gawande, Devesh Kapur

Over the second half of the twentieth century, conflicts within national boundaries have become increasingly dominant. One third of all countries have experienced civil conflict. Many (if not most) such conflicts involve violence along ethnic lines. Based on recent theoretical and empirical research, this paper provides evidence that pre-existing ethnic divisions do influence social conflict. The analysis also points to particular channels of influence. Specifically, it is shown that two different measures of ethnic division — polarization and fractionalization — jointly influence conflict, the former more so when the winners enjoy a “public” prize (such as political power or religious hegemony), the latter more so when the prize is “private” (such as looted resources, government subsidies or infrastructures). The available data appear to stand in strong support of existing theories of inter-group conflict. Our argument also provides indirect evidence that ethnic conflicts are likely to be instrumental, rather than driven by primordial hatreds.
Laura Mayoral, Joan Esteban, Debraj Ray

Miguel, Satyanath, and Ernest Sergenti (2004), henceforth MSS, show that economic growth is negatively related to civil conflict in Africa, using annual rainfall variation as an IV for growth. Antonio Ciccone (2011) argues that thanks to rainfall’s mean-reverting nature, rainfall levels are preferable to annual changes. We make three points. First, MSS’s  findings hold using rainfall levels as instruments. Second, Ciccone (2011) does not provide theoretical justification for preferring rainfall levels. Third, the first-stage relationship between rainfall and growth is weaker after 2000, suggesting that alternative instruments are needed when studying recent conflicts. We highlight the accumulating microeconomic evidence that adverse economic shocks lead to political violence.
Shanker Satyanath and Edward Miguel

We previously documented a link between climate variation and historical civil wars in sub-Saharan Africa . Buhaug disputes this link, generating a series of animated news reports. The relationship between climate and conflict is an important topic that deserves careful scientific scrutiny, but we believe Buhaug’s approach is undermined by basic econometric mistakes, leading to what is currently an unhelpful debate. We briefly describe two main shortcomings in his analysis here . . . 

In a recent paper, we documented strong historical linkages between temperature and civil conflict in Africa. Sutton et al. raise two concerns with our findings: that the relationship between temperature and war is based on common trends and is therefore spurious, and that our model appears overly sensitive to small specification changes. Both concerns reflect a basic misunderstanding of the analysis.
Shanker atyanath, Marshall Burke, Edward Miguel, John Dykema, and David Lobell