My Ph.D. thesis is to explore the conditional relationship between natural disasters and civil conflicts and ask “under what conditions do natural disasters lead to civil conflicts”. Natural disasters are widely seen as the “threat multiplier” and contribute to civil conflicts. This security threat of natural disasters is getting worse with more extreme weather events as the ongoing climate change (IPCC, 2018). In the recent COP26, “the deadly combination of more natural disasters and ongoing conflicts” was emphasized repeatedly to alert the policy-makers (ICRC, 2021, IRC, 2021). I intend to establish a theoretical framework that incorporates the three-way strategic interaction among the government, the population, and rebel groups to better understand the effect of natural disasters on civil conflicts. Guided by this theoretical framework, I intend to empirically test within-country variation in disaster location, rebel capacity, and government capacity and examine how they affect the disasters-civil conflict link. For my thesis, I will choose the Philippines and Indonesia, which suffer from both high intensities of natural disasters and civil conflicts, as my testing ground.