Clinical Trial Carbon Footprint

Published carbon footprint estimates for academic trials range from approximately 8 tonnes to over 900 tonnes CO2e, illustrating extreme heterogeneity. Per-patient carbon footprint varies dramatically by trial size: the small single-centre phase I trial produced ~269 kgCO2e per patient versus ~5 kgCO2e per patient for the large multicentre phase III trial. The two assessed French trials (3.2 and 5.8 tonnes CO2e) fall well below published values for other academic trials. Patient travel to hospital for trial-specific visits is commonly cited as an emission source in other studies, but did not apply to either French trial since neither required patient travel beyond standard care. Academic clinical trials remain understudied in carbon footprint research, with most existing publications coming from the UK. Meetings and travel and CTU emissions are consistently the two primary carbon hotspots in academic clinical trials, consistent with findings across the broader published literature.