Identifying uncertainties in the whole life carbon assessment of buildings: Sources, types, and potential actions

Uncertainties in the life cycle assessment (LCA) of buildings affect the environmental performance benchmarking and can lead to incorrect decision-making. Reducing greenhouse gas (GHG) emissions caused by buildings is an important climate action, hence, identifying and addressing uncertainties in the Whole Life Carbon Assessment (WLCA) of buildings is imperative. However, there is no consensus regarding the sources and types of building LCA uncertainties. This study identified these uncertainties and classified them using an actor-oriented typology. A systematic literature review (SLR) was conducted to identify the most influential sources. Specifically, we investigated the sensitivity and scenario analyses in the reviewed publications, harmonized the uncertainty influence measures, and conducted cluster analysis for grading these uncertainties. The results show that individual sources of uncertainty measured as “most-influential” in some studies were “least-influential” in other studies, e.g., the deviation caused by energy mix ranged from 3% to 910%. Such conflicting results across studies suggest that further studies on uncertainty influence measures for specific building typologies and contexts are required. Nevertheless, nine sources of uncertainty were “most-influential” in more than half of the reviewed studies. In line with the actor-oriented typology, this study gives recommendations to standardization and legislative bodies, environmental data providers, and designers on how to address the uncertainties in the WLCA of buildings.