A global initiative to develop low-carbon, resilient health systems-the COP26 Health Programme-launched at the UN Framework Convention on Climate Change 26th Conference of the Parties (COP26) in 2021. As of May, 2024, 83 nations have committed to participate in this initiative. This analysis evaluates the effectiveness of existing and proposed indicators towards public monitoring and accountability to these commitments. Our findings reveal substantial gaps in data availability and indicator relevance, with many countries reporting process indicators that do not reflect actual progress towards achieving sustainable health-care systems. We found a dearth of suitable indicators and an urgent need to develop robust ones that are adaptable to different health-care system contexts. These indicators should be designed to capture tangible outcomes, support policy making, and prevent greenwashing. Integration of more robust indicators into independent scientific monitoring can support systematic inclusion of health care in global climate strategies, thereby enhancing the overall effectiveness of the COP26 Health Programme.