Funding Information: Competing interests: The BMJ has judged that the authors have no disqualifying financial ties to commercial companies that are relevant to this paper. The authors declare the following other interests: CS is a member of the Association of Anaesthetists Environment and Sustainability Committee and the Health Education England North West Sustainability Healthcare Working Group. He has received travel expenses from the Association of Anaesthetists and Health Education England to attend professional meetings to speak on sustainable healthcare. He has received a grant from the Manchester Foundation Trust Charity to run the ‘Greener Operations’ research priority setting partnership. Manchester University NHS Foundation Trust, where CS practices, has received a cost free loan of nitrous oxide cracking equipment and associated consumables for clinical evaluation purposes from Medclair Invest and BPR Medical. RK is a member of the steering group of the Greener Operations research priority setting partnership, and has received patient and public involvement payments for this work. RS is vice chair of the American Society of Regional Anesthesia Green Special Interest Group and chair of the Canadian Anesthesiologists’ Society Section on Environmental Sustainability. FM has received grants from Australia and New Zealand College of Anaesthetists, National Health and Medical Research Council and the Medical Research Future Fund for research on environmental sustainability and healthcare. He is a member of the Australia and New Zealand College of Anaesthetists Sustainability Network and the Australia and New Zealand Intensive Care Society Environmental Sustainability Planning Group, and is vice chairperson of sustainable healthcare for Doctors for the Environment Australia.