The greenhouse gas emissions of psychological conferences and what we can do about it

The UN Sustainable Development Goals highlight the relevance of climate change for global health. At the same time, the academic community—including health-related disciplines such as psychology and behavioural medicine—contributes substantially to greenhouse gas emissions, particularly through work-related travel. To inform discussions on the environmental impact of academic conferences, this study estimates the CO₂-equivalent (CO₂eq) emissions resulting from attendance at major international psychology conferences. The number of in-person and online attendees at major international psychological conferences was identified by web search and email inquiries. Conference inclusion criteria: International, psychology/behavioural medicine, 1,000 + attendees, years 2023–2025. Total and per capita CO₂eq were estimated separately for in-person and online attendance using emission factors derived from 22 studies on in-person conferences and 10 on online conferences. Attendance at an international in-person conference resulted in an estimated 1.26 t CO₂eq per participant, with approximately 94% attributable to travel, compared to 0.02 t CO₂eq for online attendance—corresponding to a reduction rate of about 98%. Across the 21 included major international psychology conferences, total emissions were estimated at approximately 63,481 t of CO₂eq. These estimates illustrate the scale of greenhouse gas emissions associated with conference-related travel in academia. By quantifying emissions from major international psychology conferences—while excluding numerous smaller and regional meetings—this study provides empirical reference points to inform ongoing discussions about conference formats and travel practices among individual scientists, institutional departments and scientific organisations.