Time to re-think engineering design standards in a changing climate: the role of risk-based approaches

The design and construction of the built environment requires explicitly addressing the risk-resilience tradeoff – too weak and the structure may fail, too strong and it will result in excess capacity, cost and embodied energy. This tradeoff is generally managed through the establishment of, and compliance with building standards and codes that often specify the exact methodology by which design parameters shall be calculated from environmental measurements of wind speeds, wave heights, flood levels and other environmental variables. Furthermore, these standards commonly legislate that historical data be used to calculate these design parameters. However, climate science has revealed that in some, if not many cases, these historical datasets may not be representative of future conditions and thus using historical data to develop design parameters for future long-lived infrastructure may increase the likelihood that the risk-resilience tradeoff becomes inadvertently skewed. Hence we now have a conundrum in that engineers are directed to design structures using standards that are based on time series on environmental parameters that we believe in some cases may be unrepresentative of the conditions which structures may face.