Can we reliably estimate future flood risk?
17 April 2013
Cabot Institute researchers Andy Smith, Paul Bates and Jim Freer publish paper on how reliable it is to estimate future flood risk using climate models.
As well as increasing surface temperatures, global warming is expected to alter other fundamental mechanisms of the global climate system. This includes changes to the large scale hydrological cycle, with the widely held hypothesis being that the hydrological cycle will intensify resulting in increased flood risk with further greenhouse-gas induced global warming. Research focused on producing future flood risk projections has therefore been receiving considerable effort, with climate models now widely used to make projections of future changes.
In this study, eighteen regional climate models covering the U.K are analysed across different catchments. The performance of the climate models has been outlined in order to explore how the ability to make confident statements about future flood risk varies between different catchments.
We find that the models do have some skill in representing precipitation, however model performance varies across different catchments and different seasons. For future changes in monthly mean precipitation we observe the clear ‘drier summers/wetter winters’ signal used to develop current UK policy. But when we look instead at flood generating rainfall this seasonal signal is less clear, and greater increases are projected.
Furthermore, the confidence associated with future projections varies from catchment to catchment and season to season as a result of the varying ability of the climate models. In some cases, estimating future flooding using climate model outputs may be highly problematic.
For more information about this paper, contact Andy Smith
Smith A, Bates P, Freer J, Wetterhall F. 2013. Investigating the application of climate models in flood projection across the U.K. Hydrological Processes, DOI: 10.1002/hyp.9815