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Importance: Greenhouse gas emissions associated with medical conferences have been associated with climate change, and the effects of climate change have been associated with an increased incidence of ophthalmic diseases. Identifying practical strategies associated with reducing these emissions may be warranted.
Objective: To assess greenhouse gas emissions associated with in-person and virtual meetings of the American Academy of Ophthalmology (AAO) and to conduct mitigation analyses to suggest strategies to reduce future emissions.
Design, Setting, And Participants: Quality improvement study in which attendee and conference data were used to estimate emissions from in-person (October 12 to October 15, 2019, San Francisco, California) and virtual (November 13 to November 15, 2020) AAO annual meetings for 35 104 attendees. The data were also used to perform mitigation analyses to assess whether meeting format alterations could be used to reduce future emissions. Data were analyzed from December 21, 2021, to April 18, 2022.
Exposures: Attendance at a selected meeting. Total attendance was 23 190 participants in 2019 and 11 914 participants in 2020.
Main Outcomes And Measures: Greenhouse gas emissions produced by the in-person meeting were estimated by calculating the equivalent metric tons of carbon dioxide (CO2) associated with attendee transportation, attendee accommodations, and the conference venue. Emissions produced by the virtual meeting were estimated by calculating the equivalent metric tons of CO2 associated with attendees' computer use, network data transfer, and video-conferencing server use. Mitigation analyses simulated the association of changing the meeting location and format with reductions in emissions.
Results: In this analysis, the 2019 in-person meeting produced 39 910 metric tons of CO2 (1.73 metric tons of CO2 per capita), and the 2020 virtual meeting produced 38.6 metric tons of CO2 (0.003 metric tons of CO2 per capita). Mitigation analyses showed that holding a single in-person meeting in Chicago, Illinois, rather than San Francisco, California, could be associated with transportation-related emissions reductions of 19% (emissions for the San Francisco meeting, 38 993 metric tons of CO2; for the Chicago meeting, 31 616 metric tons of CO2). Holding multiple in-person meetings in separate regions could be associated with transportation-related emissions reductions of as much as 38% (emissions for the San Francisco meeting, 38 993 metric tons of CO2; for multiple meeting scenario 2, 24 165 metric tons of CO2).
Conclusions And Relevance: This study found that the AAO's 2019 in-person meeting was associated with substantially higher greenhouse gas emissions compared with the 2020 virtual meeting, primarily due to transportation-related emissions. Increasing the proportion of virtual participants, holding the meeting in locations chosen to minimize transportation-related emissions, or offering multiple regional meeting locations may reduce the carbon footprint of future meetings.
