<p>The convergence of climate shocks and armed conflict poses a critical threat to human security and sustainable development. However, their joint impacts on human populations, particularly the erosion of psychosocial resilience, remain poorly quantified. Here, integrating georeferenced drought data from respondents’ pre-displacement regions with survey data from Syrian and Iraqi refugees (<i>N</i> = 3,751), we find that the association between war exposure and post-traumatic stress is stronger among those from more drought-affected areas of origin. Under severe drought conditions, the increase in post-traumatic stress associated with war exposure was more than twice as large as under average moisture conditions. This pattern is consistent with resilience corrosion, whereby climate-induced hardship may degrade mental health and weaken the adaptive capacities communities need to navigate future shocks. These findings support policy approaches that integrate mental health into climate adaptation and humanitarian response in settings shaped by overlapping crises.</p>