The UN Environment Programme's 2023 assessment highlights the urgency of unprecedented mitigation action to limit global warming. While large-scale decarbonization efforts focus on major emission sectors, the role of diverse stakeholders, including universities and academic societies, is crucial. Academic conferences, traditionally important for knowledge dissemination and collaboration, often involve significant international travel, contributing substantially to greenhouse gas emissions. Studies reveal that conference travel can comprise a significant portion of an individual researcher's or university's carbon footprint. While virtual conferences offer a potential solution, many academics value the networking and social aspects of in-person events. This study aims to quantify the environmental impact of in-person academic events and develop a behavior change strategy to mitigate their greenhouse gas emissions, leveraging the COM-B framework.

Several studies have assessed the GHG emissions of academic conferences, suggesting strategies like online-only events, hybrid models, and sustainable venue choices. However, these strategies often overlook the critical aspect of individual participant behavior change. The 'motivation-impact gap' demonstrates that even with awareness of environmental issues, individuals often struggle to adopt pro-environmental choices. Implementation science, and specifically the COM-B behavior change model, offers a robust framework for understanding and influencing individual behavior. This model considers Capability, Opportunity, and Motivation as key factors in driving behavior change. This research applies the COM-B model to the context of academic conference travel to guide effective interventions.

This retrospective analysis used data from two in-person European Academy of Nursing Science (EANS) summer schools held in Ghent, Belgium, and Lisbon, Portugal, in 2018 and 2019, respectively. The analysis included all major sources of event-related GHG emissions, namely travel (air and rail), accommodation, and food. GHG emissions were calculated based on estimated travel distances, accommodation profiles, and dietary choices. Financial costs associated with attendance were also determined. The COM-B framework was then used to categorize and map these emission sources to various behavior change strategies. Travel distances were estimated based on participant home city, using a general assumption that participants traveling internationally flew while those traveling within the same country took the train. This assumption was refined for certain instances (e.g. Maastricht, where air travel over rail would be unusual). Flight distances were calculated using Great Circle Map and Skyscanner for economy return flights. Rail distances for intra-country travel were approximated using Google Maps road distances. GHG emissions were calculated using UK Government GHG Conversion Factors, differentiating between air, rail, and coach travel. For venue emissions, data were collected from the Cornell Hotel Sustainability Benchmarking index and regional dietary averages. Financial cost data for 2023 were based on Skyscanner for flights, national rail company websites for rail, actual venue costs for hotels, and estimations for other components (assuming a 10% vegetarian adoption). The data were then analyzed to calculate total and per-person emissions, financial costs, and the relative contribution of various factors to the overall impact. The COM-B framework was subsequently applied to identify targeted behavior change strategies.

The Ghent event generated 40.77 tonnes of CO₂e emissions, and the Lisbon event generated 99.15 tonnes. The per-participant means were 0.334 (Ghent) and 0.724 (Lisbon) tonnes of CO₂e, representing 2-5.5 times the daily European average. The most significant factor influencing emissions was the distance traveled. On average, participants in Lisbon had to travel about 2.5 times farther. Air travel contributed a significantly higher proportion to the GHG emissions compared to rail (95.05% for Ghent and 99.30% for Lisbon). The financial costs were relatively similar between the two events, despite the large variation in the total emissions. Higher flight costs to Lisbon were offset by higher hotel and rail costs in Ghent. The daily per-person GHG footprint was notably higher for both events compared to the 2021 European average and the 2030 target. The on-site emissions in Lisbon were higher than Ghent due to higher emissions profiles for hotels and teaching rooms, but their contribution to total emissions was smaller due to higher travel emissions in Lisbon. The analysis revealed that venue location was the primary driver of emissions, with more centrally located venues producing significantly lower overall GHG emissions. This was due to shorter travel distances enabling participants to use ground transportation, which has a drastically lower per-kilometer CO2e footprint compared to air travel. Even though renewable energy investment might decrease on-site emissions, the dominant factor influencing the overall GHG profile remained air travel emissions. Although the difference in overall costs was only €60 per person, the results emphasized the need for event organizers to select centrally located venues with good ground-based transport infrastructure to provide participants with opportunities for more sustainable travel.

The findings highlight the substantial environmental impact of international academic events and the critical need for strategic interventions. Venue location significantly influences emissions, making it a key lever for change. The COM-B framework provides a structured approach to address behavior change at both the organizational and individual levels. Opportunity is enhanced by choosing centrally located venues with good alternative transport links and sustainable on-site practices. Capability is improved by providing resources and information on sustainable travel options. Motivation is enhanced through incentives, feedback on the environmental impact of choices, and transparent sustainability policies. The combination of these strategies is crucial; no single action is sufficient. This framework needs to be considered within the wider academic context that values international collaboration, which often incentivizes international travel. Universities have a key role to play in creating policies that encourage more sustainable practices among their staff.

This study demonstrates that academic societies can significantly reduce GHG emissions from their face-to-face events by strategically selecting venues and implementing targeted behavior change strategies. The COM-B framework provides a practical tool for this process, addressing opportunities, capabilities, and motivations. Future research should involve testing this framework in practice, collecting data on implementation and outcomes to refine the model's effectiveness. Collaboration between organizing societies, universities, and researchers is critical to drive wider adoption of sustainable practices in the academic sector.

This study relies on secondary data, making certain assumptions about travel modes, neglecting travel distances from participants' homes to airports/stations, and not accounting for home-based computer use. The analysis focuses on European events with European participants, limiting the generalizability to other contexts, where intercontinental travel and different transport infrastructures are common. It also does not explicitly factor in the varying socioeconomic factors influencing travel behavior and capabilities.