Classification of sources of uncertainty in building LCA

Life Cycle Assessment (LCA) is a widely used scientific method to assess the environmental indicators of buildings. In several LCA case studies, a single point estimate is often used to assess the sustainability indicators such as embodied energy and embodied greenhouse gas emissions. One of the key concerns with this approach is that there is lack of understanding on uncertainty in the results as a result of variability in the input parameters. Study of uncertainty in building LCA is essential to incorporate the variability in the input data and its effect on LCA results. This study presents a classification of sources of uncertainty in building LCA and identifies uncertainty factors based on a comprehensive review of 48 studies conducted across the globe. Sources of uncertainties are broadly grouped into four categories namely early design decisions, input data and data quality issues, future stages (service life of building components, reference study period of buildings, end -of -life stage choices and climate change) and the LCA methods (type of life cycle inventory technique and impact assessment methods). This study helps in strengthening the understanding of uncertainty in building LCA and lays the foundation to arrive at robust results for future case studies.