Denise Thomson, Amanda S. Newton, Lisa Hartling, Ken J. Caine, Laura Hand, Arlene Oetomo, Kristie L. Ebi
Rationale As climate change intensifies, health systems must integrate climate resilience and decarbonisation as core functions. This requires a climate lens to coordinate diverse climate-related initiatives across all system functions (e.g. public health, clinical care, facility management and system management). Objective We compared the adoption of a climate lens in the health systems in two Canadian provinces (British Columbia and Ontario), to identify the contextual and social/cognitive factors influencing implementation and normalisation processes. Methods Drawing on 428 documents and webpages and 41 semi-structured interviews, our exploratory analysis used Normalization Process Theory and implementation science frameworks to assess how social and cognitive processes influence implementation. Results We found that normalisation is an emergent, socially constructed process shaped by system architecture, leadership, resource allocation and relational networks. In British Columbia, formal accountability mechanisms streamlined implementation; in Ontario, local leadership and relational networks drove progress despite lacking provincial mandates. Ultimately, individual staff members sustain climate-health policies and programs by deploying policy capacity to bridge gaps and boundaries in formal system structures. Conclusions These findings offer a roadmap for health systems to support and advance sustained climate action, highlighting how progress can be achieved through both formal policy mandates and local leadership networks.