02 Fakultät Bau- und Umweltingenieurwissenschaften
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Item Open Access Systematising the LCA approaches’ soup : a framework based on text mining(2024) Di Bari, Roberta; Alaux, Nicolas; Saade, Marcella; Hong, Sun Hea; Horn, Rafael; Passer, AlexanderPurpose. It is challenging for practitioners to navigate through the multitude of life cycle assessment (LCA) approaches due to the rich literature and a lack of systematisation. The LCA flexibility allowed by standards results in a multitude of applications and, as referred to in previous works, as an “alphabet soup”. This paper proposes a scheme for a clearer classification of currently used LCA approaches, with consideration of the 4-stage framework coming from standards. Methods. This systematisation was first established through literature research serving as a preliminary tentative framework. A text mining task was carried out in a second stage, involving 2044 published articles among 7558 of the last 10 years. For text mining, a dictionary collected keywords and synonyms of the LCA approaches. Such keywords were then extracted from the text together with their context (multiword). The final multiword analysis allowed the association of each keyword (i.e. each LCA approach) with a specific LCA stage (Goal and Scope, Life Cycle Inventory, Life Cycle Impact Assessment, Interpretation). The preliminary framework was adapted, further enriched and validated based on the text mining results. Results. As a result of the text mining activities, the preliminary tentative framework was partially confirmed and enriched with new insights, especially in the field of “explorative” LCA approaches, which also include “prospective” and “scenario-based” LCA. For most of the currently used LCA approaches, a link to a unique LCA stage was not recorded. However, clear trends were detected. The text mining task also highlighted a high number of works in which different approaches are compared or counterposed, especially in the field of attributional and consequential LCA. Some issues were found with the connotations of “traditional” approaches, which could be defined more specifically as “non-explorative”. Conclusions. Unlike other works focused on notions from selected literature, text mining activities can provide bottom-up feedback on a larger scale more automatically. In addition, this work brought out novel LCA approaches, for which future developments will confirm a final definition and systematisation. As an additional advantage, the presented methodology is easily replicable. Hence, the presented framework can be updated along with developments in LCA approaches.Item Open Access Soil organic carbon as an indicator of land use impacts in life cycle assessment(2024) De Laurentiis, Valeria; Maier, Stephanie; Horn, Rafael; Uusitalo, Ville; Hiederer, Roland; Chéron-Bessou, Cécile; Morais, Tiago; Grant, Tim; Milà i Canals, Llorenç; Sala, SerenellaPurpose. Anthropogenic activities are a major driver of soil and land degradation. Due to the spatial heterogeneity of soil properties and the global nature of most value chains, the modelling of the impacts of land use on soil quality for application in life cycle assessment (LCA) requires a regionalised assessment with global coverage. This paper proposes an approach to quantify the impacts of land use on soil quality, using changes in soil organic carbon (SOC) stocks as a proxy, following the latest recommendation of the Life Cycle Initiative. Methods. An operational set of SOC-based characterisation factors for land occupation and land transformation were derived using spatial datasets (1 km resolution) and aggregated at the national and global levels. The developed characterisation factors were tested by means of a case study analysis, investigating the impact on soil quality caused by land use activities necessary to provide three alternative energy supply systems for passenger car transport (biomethane, ethanol, and solar electricity). Results obtained by applying characterisation factors at local, regional, and national levels were compared, to investigate the role of the level of regionalisation on the resulting impacts. Results and discussion. Global maps of characterisation factors are presented for the 56 land use types commonly used in LCA databases, together with national and global values. Urban and industrial land uses present the highest impacts on SOC stocks, followed by severely degraded pastures and intensively managed arable lands. Instead, values obtained for extensive pastures, flooded crops, and urban green areas often report an increase in SOC stocks. Results show that the ranking of impacts of the three energy systems considered in the case study analysis is not affected by the level of regionalisation of the analysis. In the case of biomethane energy supply, impacts assessed using national characterisation factors are more than double those obtained with local characterisation factors, with less significant differences in the other two cases. Conclusions. The integration of soil quality aspects in life cycle impact assessment methods is a crucial challenge due to the key role of soil conservation in ensuring food security and environmental protection. This approach allows the quantification of land use impacts on SOC stocks, taken as a proxy of soil quality. Further research needs to improve the assessment of land use impacts in LCA are identified, such as the ability to reflect the effects of agricultural and forestry management practices.