Developing willingness-to-pay-based effect factors for marine cultural ecosystem services in life cycle impact assessment

Purpose Cultural ecosystem services (CES) are absent from current Life Cycle Impact Assessment (LCIA) methods. This study investigates the use of willingness-to-pay as a basis for deriving monetary effect factors (EFs) for marine CES affected by macroplastics. To our knowledge, this study provides the first set of spatialized EFs for marine CES impacts, demonstrating how willingness-to-pay (WTP) can quantify impact on CES within the LCIA framework. Methods Monetary EFs were developed based on an European WTP survey on marine plastic removal in eight countries, additional 13 countries´ WTP were extrapolated using disposable income. Coupled with marine plastic burden in each country, the resulting 21 national EFs express the potential loss of holistic cultural utility per unit of stranded macroplastics in [€/kg] and [€/item]. The mass of an average stranded plastic item is derived from each countries’ beach cleanup results. The dual units ensure compatibility with life cycle inventories. A case application in the Froan Archipelago (Norway) illustrates the relevance of the EFs and their role in the LCIA cause–effect chain, linking plastics stress to CES loss. Results and discussion The WTP-based EFs enable the quantification of CES impacts in monetary terms consistent with existing LCA monetization. National EFs varied greatly, ranging from 233 €/kg to 1,730,000 €/kg by mass and 7.41€/item to 74,200 €/item by item count. The population-weighted averages for Europe were 65,200 €/kg and 5,310 €/item, respectively. This variability was driven mainly by differences in estimated stranded plastic burden, while WTP differences, reflecting economic and cultural contexts, contributed to a smaller extent. Incorporating WTP-based valuation offers a transferable means for integrating impacts on ecosystem services into LCIA. Conclusions This study demonstrates that WTP provides a practical and conceptually coherent basis for quantifying CES impacts within LCIA. The proposed EFs represent an initial step toward monetized characterization factors for CES damages from macroplastics. The framework enhances the representation of ecosystem services in LCA and can be extended to other environmental stressors and geographic contexts.