Climate Change as a Security Threat Multiplier in Nigeria: Variability, Vulnerability, and the Lake Chad Divergence

Climate change is widely described as a security threat multiplier in Nigeria, and accounts of the Lake Chad Basin commonly rest that description on the continuing contraction of the lake. The hydrological record contradicts that premise. Lake Chad fell from approximately 25,000 square kilometres in the 1960s to roughly 2,000 square kilometres by the mid-1980s and has since recovered and stabilised at approximately 14,000 square kilometres, with multi-satellite analysis establishing stable extent across two decades and increasing groundwater storage since the 2000s. Conflict in the basin intensified across precisely that period of recovery. This article takes the divergence as its analytical starting point and argues that it falsifies scarcity accounts while confirming vulnerability accounts, and that climate accordingly operates on Nigerian security through variability rather than through aggregate resource decline. The study engages the sceptical literature directly, accepting the sampling bias critique, the positivist critique, and the expert-assessment finding that specialists regard climate as a comparatively minor and highly uncertain conflict driver. It responds by restricting its claim to within-case falsification, which does not require the representativeness that estimation of average effects would demand. Employing spatiotemporal econometric analysis for 2000 to 2024, scenario modelling to 2035, and comparative case analysis, the study identifies crop yield and food price variability as the principal transmission channels, with convergent support from experimental and pastoral mobility evidence, and identifies governance capacity, market access, and security infrastructure as moderators strong enough that identical climatic anomalies produce materially different conflict outcomes. The article concludes that adaptation planning should target income stabilisation rather than aggregate resource augmentation, and that climate security assessment should abandon the lake contraction narrative, which is factually superseded and which obscures the governance failures it displaces.