How to manage uncertainty in future Life Cycle Assessment (LCA) scenarios addressing the effect of climate change in crop production

When Life Cycle Assessment (LCA) is used to provide insights on how to pursue future food demand, it faces the challenge to describe scenarios of the future in which the environmental impacts occur. In the case of future crop production, the effects of climate change should be considered. In this context, the objectives of this paper are two-fold: (i) to recommend an approach to deal with uncertainty in scenario analysis for LCA of crop production in a changed climate, when the goal of the study is to suggest strategies for adaptation of crop cultivation practices towards low environmental impacts, and (ii) to implement the suggested approach to spring barley cultivation in Denmark. First, the main implications of climate change for future crop cultivation are analyzed, and the factors which should be included when modeling the climate change effects on crops through LCA are introduced, namely climate, soil, water loss and production parameters. Secondly, the handling of these factors in the inventory modeling is discussed and finally implemented in the case study. Our approach follows a 3-step procedure consisting of: (1) definition of a baseline scenario at the Life Cycle Inventory (LCI) level for the selected crop and performance of Life Cycle Impact Assessment (LCIA) including normalization and contribution analysis, in order to identify the focus points in terms of impact categories, unit processes and substances; (2) identification of the main deviations from the baseline scenario for these key parameters in alternative future scenarios; (3) comparison of the different scenarios including quantification of the uncertainty at inventory level. The procedure presented was successfully implemented to assess the consequences of the changed climate on Danish spring barley cultivated under future climate conditions. The LCA results, obtained using mainly primary data from phytotron experiments mimicking a future Danish climate, emphasized that adaptation strategies should prioritize the development of resilient and stable cultivars, i.e. robust to the expected extremes of the future climate and offering a reasonable yield under different climatic conditions.