Natural Hazard Risks in LCA for the Built Environment: Managing Stochastic Inputs in Stochastic Process-Based LCA.

Natural hazards affect the environmental sustainability of the built environment because of the environmental losses caused, such as the environmental impacts of the repairs and the indirect effects of downtime. Asset performance assessment workflows allow for probabilistically connecting frequent and infrequent hazards with building response, damages, and environmental losses. Environmental life cycle assessment is emerging as the preferred methodology to derive environmental losses, but current tools struggle with interoperability issues, prompting simplifications in converting the material damages to environmental losses and limiting environmental uncertainty propagation. This study proposes a novel coupling framework that leverages a dual presampling strategy paired with a preaggregation step on background environmental datasets, expediting in minutes the computation of thousands of stochastic environmental life cycle assessment results. The coupling framework is demonstrated with two scales of asset performance assessment workflows: one for individual buildings and one for portfolios of buildings, both exposed to a hurricane hazard. The case studies underline key loss drivers originating from different steps in the workflow, including the conversion from damages to environmental losses. The coupling framework provides groundwork for identifying natural hazard effects on the sustainability of the built environment, a key step in formulating sustainable adaptation strategies to a changing climate.