Climate change threatens human well-being and planetary health, necessitating sector-wide transitions. Recent research has highlighted the carbon footprint of hospital care by identifying hotspots and mitigation areas, but key factors influencing these outcomes remain underexplored.

This study used causal mapping of textual data to systematically evaluate scientific reports on the carbon footprint of hospital services and care pathways. The sample was drawn from a State-of-the-science literature review, focusing on quantitative reports on hospital services’ carbon footprint. Text fragments discussing factors influencing the carbon footprint were recorded, and variables and relationships were identified and visually mapped through iterative open, axial, and selective coding.

Twelve main factors influence four major domains of the carbon footprint of hospital services and care pathways. These factors are related to the volume of travel, facilities and equipment, consumables, waste disposal, and pharmaceuticals, and their carbon intensity. Over eighty subfactors were identified, including ten cross-cutting factors that affect multiple domains of the hospital care footprint.

The carbon footprint of hospital care is a multifaceted and complex issue driven by multiple factors. Insight into these factors can inform targeted actions to reduce emissions. This study also improves the understanding of the causes of variability in carbon footprint outcomes of hospital care, which is important for the interpretation and transferability of results and conclusions in this rapidly growing field of research.