The UK’s flood defences offer only limited protection against the likely impact of climate change, according to a new study by Moody’s RMS and Flood Re. The report suggests that while investment in flood defences can be effective in reducing additional losses from climate change, there are diminishing returns from such investment beyond a certain level without property-level flood resilience measures and strategies to address the management of surface water.

The research focuses on future flooding in two major conurbations exposed to severe flood risk: York, with a dense population and strong defences; and Pontypridd, with a lower population and lower standard of defence protection. It exposes the vulnerability of both areas to their existing defences being breached in the run up to 2040 – the year after Flood Re is expected to exit the UK insurance market – and the projected increases in the costs of future events.

The study considered a severe flood scenario for residential properties in York and Pontypridd using Moody’s RMS’ industry exposure database for the UK inland flood HD model, combined with the UK inland flood HD climate change model.

The findings confirm that climate change will erode existing defence standards of protection over the study period and result in significant increases in loss for both York and Pontypridd. York, which is densely populated but has high standards of flood protection, would see an £11m-£20m increase in additional losses under a 1-in-50-year flood scenario by 2040. Pontypridd, which is less populated, and less protected, would also see additional losses of between £8m-£17m.

While strengthening both areas’ flood defences would offset the additional losses, the report concludes that investment would likely suffer from a diminishing return. Andy Bord, CEO, Flood Re, said: “This study clearly shows that whilst the UK needs to continue to invest in its flood defences, this alone is not sufficient to build its resilience to flood in the wake of climate change. It is also necessary to fully embrace property-level flood resistance measures and water management strategies.

“Flood Re will continue its work with the insurance market and government to ensure by the time we exit in 2039, UK housing is more resilient to flooding and householders are still able to obtain affordable insurance.”

Daniel Bernet, senior product manager at Moody’s RMS, added: “The UK is one of the best defended countries in the world for flood risk. However, climate change presents an enormous challenge to defence infrastructure. Our study clearly shows that whilst investment in flood defences has an important role to play, strengthening the flood defence infrastructure is just one solution amongst multiple adaptation measures that will be required to keep the increase in flood risk driven by climate change at bay.”

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