Cradle-to-Grave LCA of In-Person Conferences: Hotspots, Trade-Offs and Mitigation Pathways

Scientific conferences are invaluable for knowledge exchange, yet pose growing environmental concerns, especially through long-distance travel. This work quantifies and compares the environmental burdens of a national conference (30 delegates, Pisa, Italy) and an international conference (50 delegates, Athens, Greece) using ISO 14040/44-compliant Life-Cycle Assessment (LCA). A cradle-to-grave inventory combined primary data on participant travel, venue utilities, catering materials and waste handling with secondary datasets from Ecoinvent 3.8. Sixteen midpoint impact categories were calculated with the Environmental Footprint 3.1 method and normalized per delegate. The international meeting incurred 130 kg CO 2eq per delegate, compared with 11 kg CO 2eq per delegate for the domestic event, reflecting a ten-fold rise in fossil energy demand and comparable multiples across acidification, eutrophication and toxicity categories. Participant travel explained >85% of every global indicator in both cases, while venue energy and material flows together accounted for ≤12%. Further developments require harmonized functional units, improved digital-infrastructure inventories and integration of social impact metrics. The findings provide preliminary input for evidence-based guidelines for organizers and contribute to the standardization of LCA in the emerging field of event sustainability.