Health systems’ responses to climate change: an umbrella review of systematic reviews

Background Climate change places increasing pressure on health systems. They must both reduce their negative impact on the environment and strengthen resilience to climate-related risks. Objective To synthesize and map the evidence from systematic reviews on the scope and effectiveness of climate change mitigation and adaptation actions in health systems. Methods An umbrella review of systematic reviews examining health system responses to climate change was conducted. The review followed the Joanna Briggs Institute methodological guidelines and adhered to the PRISMA checklist. The included systematic reviews had to meet two overarching criteria: at least two databases were searched, and a predefined instrument was used to assess the quality or risk of bias of the included studies. Results Thirty-nine systematic reviews published between 2020 and 2025 were included, covering 933 individual studies. Most reviews (35/39) focused exclusively on mitigation strategies, with evidence concentrated around major greenhouse gas emission hotspots: surgical procedures; radiology; pharmaceuticals; food waste; and transportation of patients and staff. Across these areas, many mitigation strategies were associated with environmental and economic co-benefits, although the underlying evidence was heterogeneous and often of low to moderate quality. In contrast, only a small number of reviews addressed climate adaptation and health system resilience. Conclusions Existing evidence provides practical guidance on effective climate mitigation actions. The limited number of systematic reviews on climate adaptation highlights a gap in the evidence base. Translating mitigation evidence into clinical guidelines and policies and strengthening research on adaptation could support more systematic climate action in health systems.