What is the carbon footprint of a 100% digital pathology scenario in France?

Healthcare systems contribute to 5-10% of annual greenhouse gas (GHG) emissions and must reduce them to meet the 2016 Paris Agreement targets. Workflows in many areas of medicine are digitised, including surgical pathology (SP). This is the case in France, the second most populous country in the European Union (68 million inhabitants/0.8% of world population) with an energy supply that is primarily sourced from nuclear power. We aimed to evaluate the carbon footprint (CF) in a theoretical scenario where all French SP laboratories implement full digitisation. Data on annual SP activities were obtained from the French National College of Pathologists. We defined the steps required by histological slide digitisation (scanning, image management software [IMS], data workflow, desktop tools, and storage) and inventoried the tools and their CF using a specific database and bibliography. This study was extrapolated to a national digitisation scenario without artificial intelligence (AI). Digitisation of a single French laboratory was also compared to the same laboratory, non-digitised. In 2021, 28,932,624 slides were generated, corresponding to more than 43 PB [1.5 GB per whole-slide image (WSI)] shared by 250 SP laboratories using 500 scanners (i.e., two per laboratory working 12 h per day). Digitising pathology resulted in 1,103 to 1,259 t of carbon dioxide equivalent (CO2eq) for three months compared to 2,116 to 2,923 t CO2eq for one year of digital storage. This is equivalent to the GHG emissions of a combustion-powered car travelling around the Earth 145 times and 336 times, respectively. Data storage was the main contributor to the CF, regardless of storage type and duration (local or external for three months or one year). The other contributors included, in decreasing order, desktop tools, scanners, and IMS. Finally, for one French SP laboratory, the CF of full digitisation increased by 4%-8% (three months to one year of digital storage) compared to the current non-digitised CF. Such additional impact was equivalent to adding 13 to 26 -80°C freezers in the laboratory. Full digitisation of SP has a significant environmental impact on global warming, even without the use of AI. Reducing storage duration and increasing the lifespan of digital equipment are the main strategies to mitigate these impacts.