A Comparative Case Study of Collaborative Governance for Intersectoral Extreme Heat Response in Vancouver, Toronto, and Montreal, Canada

Climate change is an urgent global crisis requiring collaboration across sectors, including public health. In Canada, extreme heat is a leading cause of weather-related mortality, and cities play a central role in mitigating health impacts. This study examined the governance mechanisms shaping intersectoral extreme heat response in Vancouver, Toronto, and Montreal, Canada. Using a comparative case study methodology, we conducted semi-structured interviews (N = 28) and reviewed local heat response documents (N = 30) between November 2023 and December 2024. Thematic analysis informed cross-case comparisons of governance mechanisms shaping collaborative efforts. Across cases, legislative mandates, formal response plans, and coordinating structures for network engagement supported effective intersectoral collaboration. However, collaboration varied in terms of network governance leadership, intersectoral scope (i.e., the type and number of sectors involved), degree of engagement, and the roles of public health authorities. Co-leadership across sectors in Montreal seems to enable greater intersectoral engagement and integration of heat strategies. Areas for improvement include community-engaged heat response planning and enhanced capacity for conducting heat response outcome evaluations. Public health authorities may inform the strategic direction of future heat strategies by supporting the application of a population health lens and facilitating intersectoral collaboration to better address the upstream determinants of heat health inequities.