Schaller, Nathalie and Kay, Alison L. and Lamb, Rob and Massey, Neil R. and Van Oldenborgh, Geert Jan and Otto, Friederike E. L. and Sparrow, Sarah N. and Vautard, Robert and Yiou, Pascal and Ashpole, Ian and Bowery, Andy and Crooks, Susan M. and Haustein, Karsten and Huntingford, Chris and Ingram, William J. and Jones, Richard G. and Legg, Tim and Miller, Jonathan and Skeggs, Jessica and Wallom, David and Weisheimer, Antje and Wilson, Simon and Stott, Peter A. and Allen, Myles R. (2016) Human influence on climate in the 2014 southern England winter floods and their impacts. Nature Climate Change, 6 (6). pp. 627-634. ISSN 1758-678X
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Abstract
A succession of storms reaching southern England in the winter of 2013/2014 caused severe floods and £451 million insured losses. In a large ensemble of climate model simulations, we find that, as well as increasing the amount of moisture the atmosphere can hold, anthropogenic warming caused a small but significant increase in the number of January days with westerly flow, both of which increased extreme precipitation. Hydrological modelling indicates this increased extreme 30-day-average Thames river flows, and slightly increased daily peak flows, consistent with the understanding of the catchment’s sensitivity to longer-duration precipitation and changes in the role of snowmelt. Consequently, flood risk mapping shows a small increase in properties in the Thames catchment potentially at risk of riverine flooding, with a substantial range of uncertainty, demonstrating the importance of explicit modelling of impacts and relatively subtle changes in weather-related risks when quantifying present-day e_ects of human influence on climate.