Global land use impacts on biomass production—a spatial-differentiated resource-related life cycle impact assessment method

In life cycle assessment (LCA), the impact assessment on natural resources is still in the early stages of research, and the impacts of biotic resources are usually not evaluated. The human appropriation of net primary production (HANPP) is a well-known indicator of land use impacts, but it cannot be easily implemented in LCA. The objective of this paper was to create a life cycle impact assessment (LCIA) method on land use impacts on net primary production (NPP) based on the HANPP approach. To create an operational LCIA method, the midpoint characterization factors (CF) were calculated by comparing the NPP of plants occurring under current land uses with a baseline scenario, i.e., the NPP of potential natural vegetation. For the endpoint CF, we considered the backup technology concept and included in the calculation the marginal cost for additional biomass production through algae cultivation in the ocean. Site-generic and site-specific midpoint and endpoint characterization factors (CF) were created in a global scale for 162 countries and for four types of land uses (cropland, pasture, infrastructure, and wilderness). For cropland, we also created biomass-specific CF for ten particular crops in a global scale. The LCIA method was tested in particular case studies and seemed to produce comparable results, with the possibility of coupling it with other LCIA methodologies, as recipe endpoint. The LCIA method proposed in this paper provides an assessment of the decrease of biomass availability due to land use (affecting the AoP resources), which is an impact category poorly considered in LCA. Nevertheless, the method has some future challenges, for instance to take into account site-specific backup technologies for the endpoint CF.