A Systematic Review of Statistical Evidence on Climate-Related Migration, Immobility, and Conflict: No General Effect and Substantial Evidence Gaps

Migration is a central feature of development and climate resilience. Yet, it is increasingly framed as a pathway through which climate may affect conflict, despite fragmented and mixed evidence. We systematically review findings from 20 statistical studies to examine: When and how do climate-related migration and immobility influence conflict risk? Beyond synthesizing results, we advance conceptual thinking on the studied relationships and provide methodological guidance for future research. We find no general effect of climate-related migration on conflict, neither positively nor negatively. This confirms existing theory. Instead, effects are highly context-dependent and vary by migration and conflict characteristics. Adaptive migration can increase risks of armed conflict and civil unrest at destinations, under specific (environmental, social, or political) conditions, while reducing armed conflict at origins by acting as an escape valve. Evidence on displacement is exclusively destination focused, suggesting that flood- and storm-related displacement can raise risks of armed conflict incidence rather than onset, civil unrest in economically developing countries, and interpersonal conflict. Overall, literature is recent, topically narrow, and geographically uneven, with a strong focus on Africa. Key knowledge gaps concern mechanisms and contextual factors, conflict actors, low intensity conflicts, effects on peace, as well as the impacts of immobility and planned relocation. We further identify conceptual inconsistencies and methodological pitfalls that may bias existing evidence and outline strategies to address them. By clarifying when and how climate-related migration shapes conflict risks, this review supports evidence-based decision making that leverages migration as a successful climate adaptation in support of sustainable development and peace.