Uncertainty in prospective Life Cycle Assessment: A review of current practices and the role of scenario choice

Hjallnafoss, Súsanna Rakul Foldbo ; Nolsøe, Jóhanna Sofía Guldbrandsø

4. Term

Urban, Energy and Environmental Planning, Master

2025

2025-05-27

27 pages

In the context of the ecological crisis, assessing the environmental impacts of products and services can play a crucial role in guiding future development. Prospective Life Cycle Assessments (pLCA) have gained increasing attention in recent years, due to their ability to anticipate future environmental impacts of technologies, even when the technology is at an early stage of development. Besides the inherent uncertainties embedded in any quantification of environmental impacts, the future-oriented outlook of pLCAs introduces additional uncertainties as they depend on assumptions related to the technology’s prosperity and broader societal development. A widely suggested approach to address these uncertainties is to apply scenarios to consider multiple potential futures, instead of relying on a single projection. While scenario-based approaches can be a valuable tool for pLCA, addressing uncertainty is still an evolving practice, leading to differing approaches among practitioners. Consequently, a varying approach to account for and interpret uncertainties in pLCA can reduce the transparency and robustness of results, potentially leading to sub-optimal decision support. To address this gap, this study examines how uncertainties are addressed in current literature on pLCA, as well as what the implications of scenario choice are for the uncertainty of LCIA results. To explore how current pLCA practice addresses uncertainty and utilises scenarios, a systematic literature review was conducted using a predefined classification framework. The results show that uncertainties in pLCA are often related to a lack of knowledge and data-related uncertainties. To explore the implications of scenario choices, prospective LCIA results related to the climate change impact category were modelled across different background system activities within four sectors. The findings demonstrate that the choice of scenario affects LCIA results differently, depending on the technological and regional context, thus suggesting that the implications of a specific scenario choice can not be generalised across contexts. Combined with insights from the literature review, which revealed inconsistencies in how uncertainties are addressed, these observations suggest that current pLCA practices may contribute to a reduced transparency and reliability of results. Therefore, this study suggests further research aimed at developing a more standardised practice for addressing and managing uncertainties to increase the reliability and transparency of pLCA studies.

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