Meeting Climate Pledges Could Reduce Future UK Flood Damage By Up to 20%, Study Finds

Does it matter if countries meet their existing climate pledges, even if they currently aren’t enough to limit global heating to 1.5 degrees Celsius above pre-industrial levels?

For the UK, the answer is definitely yes, according to a new study from the University of Bristol and flood risk modeler Fathom. The researchers found that flood damage in the country could be limited to less than five percent above recent levels if the nations of the world met their COP26 climate promises through 2030 as well longer-term net zero pledges. 

“For the first time this flood model gives us a more accurate and detailed picture of the impact of climate change on the risk of flooding in the future across the UK,” study lead author, University of Bristol Professor of Hydrology and Fathom Chairman Paul Bates said in a university press release. “The results are a timely warning to the country’s political leaders and business sector that global commitments to significantly reduce carbon emissions must be taken very seriously, and ultimately take effect, in order to mitigate increased losses due to flooding.”

Flooding is considered the UK’s No. 1 environmental hazard, according to the study published in Natural Hazards and Earth System Science Tuesday. The research team looked at potential flood damage in the UK through 2070 based on five different degrees Celsius of warming above pre-industrial levels: 0.6, or 1990 levels; 1.1, or 2020 levels; 1.8, or what would happen if all COP26 and additional net zero pledges were met; 2.5, or what would happen if only COP26 pledges through 2030 were; and the worst-case scenario of 3.3 degrees Celsius of warming by 2100. The study authors based their calculations on insurance information for properties in currently at-risk areas and areas that could be at risk in the future, New Scientist explained. 

 “It’s unfortunate that quantifying impact often needs to be in pounds and dollars,” Chief Research Officer at Fathom and Honorary Research Fellow at the University of Bristol Dr. Oliver Wing told New Scientist. “Flooding can mean severe mental health implications, but it is harder to estimate these effects.”

The research team found that their model accurately predicted 2020’s flood losses–£730 million compared to the £714 million observed by the Association of British Insurers. 

“The analysis contains a greater level of detail and nuance compared to previous work, and represents our current best understanding of the UK’s changing flood risk landscape,” the study authors wrote. 

The researchers looked at what would happen to both estimated annual flood losses and losses from a one-in-100 year flood under different warming scenarios. 

Under 1.8 degrees Celsius of warming, estimated annual flood losses would rise four percent from 1990 levels and damage from a one-in-100-year flood would rise by eight percent. Under 2.5 degrees of warming, annual and extraordinary flood losses would rise by 13 and 23 percent respectively, while they would rise by a further 23 and 37 percent under 3.3 degrees of warming. 

However, even while limiting warming to 1.8 degrees Celsius would significantly reduce flood risk overall, some regions would still see damage increases of more than 25 percent, according to the press release. This included major cities London, Cardiff, Manchester, Glasgow and Edinburgh.

“Our model shows that there are many places where flood risk is growing,” Wing told BBC News. “Being able to understand the communities where this is likely to happen allows us to make sensible investment decisions – about flood defense structures, natural flood management or even moving people out of harm’s way.”

Next, the researchers intend to apply their model to other countries so they can also make these kinds of decisions, according to the press release.