A Unified Life Cycle Impact Assessment Framework for Global Terrestrial Biodiversity Decline.

Life cycle impact assessment (LCIA) translates emissions and resource use into a set of environmental impact indicators, forming a key component of life cycle assessments. Current LCIA methods quantify biodiversity loss per pressure-impact pathway separately and at various spatial scales. We developed a new, spatially explicit and scale-consistent LCIA framework and applied it to derive characterization factors (CFs) for the impacts of land use, nitrogen emissions, and greenhouse gas (GHG) emissions on global terrestrial plant diversity. The framework combines the local potentially disappeared fraction of species (LPDF) due to the selected pressures with a multipressure species-area relationship (mp-SAR) model and with information on species endemism to estimate the global PDF (GPDF). For GHG emissions, we provide CFs for 250 GHGs and 20- and 100 year time horizons. Ecoregion-specific CFs of 6 land use types varied by 7 orders of magnitude, while emitting-region-specific CFs of ammonia and nitrogen oxides varied by 2 orders of magnitude. For land use, CF variability was driven almost entirely (>99%) by ecoregion. For nitrogen emissions, emitting region and compound each explained about one-third of the variability. Overall, our LCIA framework allows for consistent scaling of local species loss to global extinction while considering multiple impacts categories.