UK flooding costs could soar 42% by 2050, warns specialist insurance modeller

The costs of UK flooding could soar by up to 42% by 2050 if no action is taken on climate change, a specialist flood modelling firm has warned.

Research by JBA Risk Management (JBA) found that climate change could push the cost of a 200-year flood event to £5 billion, up 42%, by the middle of the century under an intermediate emissions scenario (IPCC Representative Concentration Pathways or RCP4.5). Under the RCP4.5 scenario, greenhouse gas (GHG) emissions are projected to peak at 50% higher than 2000 levels by 2050. From mid-century scientists predict GHGs would then decline rapidly over 30 years.

JBA warned that if there is no action to reduce emissions, the UK could see a hike of up to 87% in average annual losses to residential properties. The modeller said there could also be a 120% increase in the cost of surface water floods, particularly in the south and east of the UK under a no-action IPCC RCP8.5 scenario. This is the worse case scenario projection where emissions continue to increase rapidly.

JBA recently launched the latest version of its UK Flood Model, which includes two new climate scenarios representing intermediate and unmitigated warming by 2050. The modellers said it incorporates “thousands of new future events, including events of increased severity and spatial coverage”.

The model also shows that while river flooding remains the main risk from climate change, particularly in the west of the country, the greatest change in flood losses comes from coastal flooding. By modelling this risk, JBA found coastal flooding showed a 150% increase under a no-action RCP8.5 scenario by 2050.

Judith Ellison, climate change commercial lead at JBA, said: “Our latest UK Flood Model has been developed using new methodology and the latest UK climate projections from the Met Office, while building on practical learnings and client feedback from our 10 years of flood modelling experience. The key element of the latest approach is the ability to build new and more severe events – with thousands of new events in total– to more effectively reflect the potential impacts from climate change and give users greater insight into the challenges of future risk.”

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