Temporal considerations in life cycle assessments of wooden buildings: Implications for design incentives

The building and construction sector plays a vital role in mitigating climate change. Consequently, the use of wood and bio-based materials as a strategy for reducing the environmental impact of buildings is increasing. However, along with realising the potential environmental benefits of biomass, the focus on assessment methods and their inherent uncertainties increases. Typically, Life Cycle Assessment (LCA) is used for quantifying the environmental performance of buildings but is often criticised for not considering temporal factors related to emissions. Therefore, dynamic LCA approaches have been developed. To understand how dynamic LCA influences building design incentives, this study compares traditional LCA and dynamic LCA results on 45 cases of wooden buildings. The study finds that the overall ranking of the buildings’ environmental performance is stable, irrespective of the method used. However, the dynamic biogenic carbon accounting methods significantly influence the results and shift burdens between upfront and future emissions. Therefore, methods for time-distributed biogenic carbon accounting crucially need addressing in LCAs of wood and bio-based products.