Climate change is expected to cause most of the meteorological drivers of Australian floods to change. Increased atmospheric temperature will lead to increases in the moisture-holding capacity of the atmosphere, which is likely to lead to significant increases in extreme rainfall intensity, particularly for short-duration convective storms. Changes to atmospheric dynamics may also be important, with the widening of the tropical belt and the southward migration of the mid-latitude storm tracks likely to lead to changes in the transition regions between climate zones. Furthermore, changes in the extreme flood-producing rainfall may be offset by a net drying of catchments in large parts of the continent, whereas increases in mean sea levels and storm surges may lead to increased flood risk in catchments close to the coastline. Each of these changes indicate that the impact of climate change on flooding will be very catchment-specific, and yet nationally-consistent guidance is required to help engineers protect Australia against future floods. The focus of this presentation is therefore to review both the science - and the practical challenges - of understanding and managing the climatic changes that can be expected in Australian flood risk.

Dr. Seth Westra has thirteen years’ research and industry experience in flood hydrology, reservoir modelling, seasonal forecasting of rainfall and streamflow, and climate change impact assessments. Research areas include analysing extreme rainfall and flood risk under climate change scenarios, stochastic generation of rainfall data for reservoir behaviour simulations, evaluation of the capabilities of global climate models to simulate hydrological data, and water security modelling. Seth is currently contributing to various aspects of the revision of the Australian Rainfall and Runoff flood guidelines (a national guidance document used by Australian engineers to estimate the risk of floods), including work on future climate change projections, continuous rainfall simulation as well as the investigation of the coincidence of extreme rainfall and coastal storm surge for estuarine flood assessments.