Updating the global weighting factor for biodiversity impact assessment in LCA.

Life‑cycle impact assessment (LCIA) is progressively expanding to address biodiversity impacts, but spatial heterogeneity continues to dominate the associated uncertainty. To account for this, the Ecoregion Factor (EF)-a dimensionless weighting coefficient-modulates biodiversity‑impact scores according to the ecological richness of the ecoregion in which a land‑use takes place. Since the initial publication, the underlying spatial datasets have been superseded by more recent releases. Consequently, we recomputed the EF using the latest ecoregional delineation and the most recent global layers for grasslands, forests and wetlands. To facilitate integration with LCIA frameworks that operate at the national level, the updated EF values were aggregated to country‑level averages by calculating an area‑weighted mean of the normalised EF across all ecoregions intersecting each nation's borders. This yields a robust geographic adjustment factor that preserves the spatial nuance of ecoregional biodiversity while making biodiversity impact assessments feasible even when inventory data are available only at the country scale. By providing an up‑to‑date, geographically calibrated weighting coefficient, the revised EF enhances the spatial granularity of biodiversity‑focused LCIA results.