Empirical engineering design based on single 'fail safe' target return periods is not appropriate in a non-stationary future climate. Extreme responses to rainfall are very likely to increase under climate change, posing increased hazards to critical infrastructure and the most vulnerable sectors of society. Structures with long life spans require reasonable estimates of the hazards that will be faced now and in the future, necessitating some assessment of future rainfall extremes. Such challenges are not new. Although future climate conditions may be unprecedented, techniques to optimize water management and minimize risk in more extreme climate regimes are not. Designs that account for future climatic extremes could benefit from other countries' experiences of highly variable extreme rainfall. This paper synthesizes the physical mechanisms leading to extreme rainfall, and their representation in climate models. It then summarizes recent observed changes in extreme rainfall and the anticipated future changes in response to changing climate conditions. Finally, it discusses ways in which different measures of extreme rainfall, such as seasonality and intensity, can be used to inform designs for future flood resilience.
