Carbovigilance

Climate change might be the biggest threat to humanity. The reduction of CO2e emissions is not only targeted at nature conservation as limiting global warming will greatly reduce the probability of sustained public health catastrophes (Lancet Countdown 2023 Global Report, WHO Operational Framework 2023). The healthcare sector accounts for over 4% of global CO2e emissions and should be at the forefront of carbon footprint reduction, including clinical trials.

Lyle et al. assessed the average carbon footprint of a clinical trial being 78.4 tonnes, based on a retrospective analysis of twelve clinical trials. Even though twelve clinical trials is a small number, it gives us a first impression. Based on this average, the Sustainable Healthcare Coalition has calculated that the total carbon footprint of all clinical trials registered on Clinicaltrials.gov (350000 trials by 2021) equals 27.4 million tonnes CO2e emissions over the full period of all trials registered.

Each year around 31000 new trials (average calculated using the data from 2015 to 2022) are registered on Clinicaltrials.gov accounting for 2.4 million tonnes CO2e emissions/year. As trialists, we should aim to reduce these 2.4 million tonnes CO2e as much as we can without compromising the quality of our clinical trials.

Guidelines like the National Institute for Health and Care Research (NIHR, located in the UK) Carbon Reduction Guidelines from 2019 are a first attempt to inform researchers and stakeholders about reducing the carbon footprint of clinical trials. According to Lyle et al., the following activities generated the most CO2e emissions: commuting to work by the trial team, study centers fuel use, trial team related travel and participant related travel.