Harmonizing the assessment of biodiversity effects from land and water use within LCA.

Addressing biodiversity impacts in life cycle assessment (LCA) has recently been significantly improved. Advances include the consideration of several taxa, consideration of vulnerability of species and ecosystems, global coverage and spatial differentiation. To allow a comparison of biodiversity impacts of different stressors (e.g., land and water use), consistent approaches for assessing and aggregating biodiversity impacts across taxa are needed. We propose four different options for aggregating impacts across taxa and stressors: equal weight for species, equal weight for taxa and two options with special consideration of species' vulnerability. We apply the aggregation options to a case study of coffee, tea and sugarcane production in Kenya for the production of 1 kg of crop. The ranking between stressors (land vs water use) within each crop and also of the overall impact between crops (coffee>sugarcane>tea) remained the same when applying the different aggregation options. Inclusion of the vulnerability of species had significant influence on the magnitude of results, and potentially also on the spatial distribution of impacts, and should be considered.