A detailed quantitative comparison of the life cycle assessment of bottled wines using an original harmonization procedure

The wine industry is facing two major environmental challenges: consumers are increasingly aware of the impacts of wine making, and production is jeopardized by environmental changes such as global warming. Therefore, there is a growing need to measure and minimize the environmental footprint of the sector. Life cycle assessment has already proven its worth in evaluating the environmental impacts and hotspots of bottled wine production. However, the methodological discrepancies in the LCA conducted do not allow conclusions regarding the most sustainable production systems or the most significant impacts for the sector. Moreover, LCA application in the field remains scarce due to the complexity of the method and the lack of readability of its results. In this study, 10 LCA papers corresponding to 17 different products were reviewed. Methodological discrepancies have been reduced through harmonization of the functional unit, the life cycle inventory and the life cycle impact assessment method, enabling provision of a range of results for different impact categories, as well as comparisons between different wines. The LCI elements that drive the results have been identified. This can be useful to simplify the data collection and the comparability of the products in this sector. Impact clusters (indicators that follow the same behaviour and are driven by the same LCI elements) have been proposed. Three clusters of impacts ((i) climate change, fossil depletion and particulate matter formation; (ii) terrestrial ecotoxicity; (iii) agricultural land occupation) are responsible for more than 90% of the single score. Nonetheless, the proposed harmonization procedure has limitations, and no conclusion can be made on the most sustainable products due to the remaining discrepancies in the system boundaries.