Decomposing climate–health vulnerability into structural, system buffering and amplification components: a longitudinal analysis in Kenya

Abstract Climate-risk assessments are widely used to evaluate how environmental hazards affect human systems, yet prevailing vulnerability frameworks do not explicitly distinguish between baseline susceptibility and the processes through which hazards translate into realised impacts. This limits both explanatory power and policy relevance. In this study, we develop and demonstrate a layered climate–health vulnerability framework that decomposes risk into structural vulnerability (baseline susceptibility), system buffering (transmission of risk) and hazard-specific amplification processes (conversion into realised impacts). Applying the framework to climate-sensitive health pathways in Kenya (1987–2023), we find that structural vulnerability explains a substantial proportion of variation in realised vulnerability (R² = 0.72, p < 0.001). Multivariate analysis shows that system buffering (β = 0.48, p < 0.01) and amplification (β = 0.31, p < 0.01) independently and significantly modify outcomes. Periods of elevated impact coincide with weakened buffering and heightened amplification. These results demonstrate that climate–health risk is governed by layered system dynamics rather than exposure alone, and identify system capacity and amplification pathways as primary targets for reducing climate-related health impacts.