Peer Review Report For: Climate Change and Sustainability in Health Professions Education: A Realist Review Protocol [version 1; peer review: 1 approved, 1 approved with reservations]

Background Climate change poses a critical global health challenge, affecting public health, healthcare systems, and health professions education (HPE). While healthcare professionals play a key role in addressing climate-related health risks and promoting sustainable practices, formal training in climate change and sustainability (CC&S) remains limited and CC&S education is inconsistently implemented due to challenges such as curriculum constraints and lack of faculty expertise. Existing systematic and scoping reviews provide an overview of CC&S interventions but do not sufficiently explore the mechanisms driving their success or failure. A realist review is needed to understand what works, for whom, and under what conditions in CC&S education. Methods This realist review will follow the RAMESES publication standards and use a structured, iterative approach to synthesise evidence. A comprehensive search strategy will be conducted across academic databases and grey literature sources to identify CC&S education interventions in undergraduate, postgraduate, and continuing professional education across healthcare disciplines. Data will be extracted using a Context-Mechanism-Outcome (CMO) framework to analyse key contextual factors, mechanisms, and outcomes influencing intervention effectiveness. Regular team discussions will ensure consensus in identifying CMOs and refining the initial programme theory. Findings will be reported through narrative synthesis, summary tables, and a graphical representation of the final programme theory. Discussion This review will provide practical insights for stakeholders on how to effectively integrate CC&S education into HPE curricula. By unpacking mechanisms and contextual factors, it will go beyond traditional systematic reviews to explain why and how these interventions succeed or fail. The findings will inform curriculum development, faculty training, and policy recommendations, ensuring that future healthcare professionals are equipped to address climate-related health challenges and advance sustainable healthcare practices. Ultimately, this review will contribute to the global effort to embed sustainability within HPE, preparing the healthcare workforce for a changing climate. Systematic review registration: Open Science Framework (OSF)