The changing risk of coastal flooding in the United Kingdom

On the night of 31 January 1953, Britain experienced one of the worst natural disasters in its modern history. Strong northerly winds swept over the North Sea, driving an unusually high sea level, known as a storm surge, towards the coast. The surge raised water levels by approximately 2m above the expected high tide, leading to widespread flooding across the UK, the Netherlands, Belgium and Germany. In England alone, 307 people lost their lives and more than 32 000 people were evacuated. Damage to sea defences cost an estimated £50 million, equivalent to over a billion pounds today (Haigh et al., 2017). Since then, the UK has made significant investments in coastal flood defences and early warning systems. The first flood risk management strategy in England was developed for the Thames Estuary. This includes the Thames Barrier, the second largest moveable flood barrier in the world, alongside a network of embankments, walls and other defences along the river (Department for Environment, Food, & Rural Affairs and Environment Agency, 2025). Together, these defences protect 1.4 million people. Anthropogenic climate change will almost certainly lead to continued global sea level rise, although the projected regional pattern of change is complex. Continued investment in adaptive flood risk management aims to reduce the impact of future storms compared to the disaster of 1953. The design, condition and performance of coastal defences are also important when considering the management of flood risk. To support long-range forecasting of events like the 1953 coastal flood, the UK Met Office developed, in 2016, a set of 30 distinct large-scale atmospheric weather patterns (Figure 1). Each weather pattern is generated based on mean sea level pressure data using statistical clustering techniques (Neal et al., 2016). They are particularly useful for forecasting on timescales of days to weeks, and specific weather patterns have been identified as increasing the risk of coastal flooding for different locations. Methodologically speaking, for each day in the historical data, the observed weather pattern is matched to the observed surge at tide gauges and wave height at offshore buoys. Extreme conditions are defined using a high threshold (the 99.7th percentile), and the likelihood of exceeding this threshold is calculated. Weather patterns with more than a 1% chance of exceeding the site locations' threshold are classified as ‘at-risk’ weather patterns. More than half a century after the 1953 disaster, Storm Xaver brought strong northwesterly winds to the UK in December 2013, generating a large storm surge that caused significant coastal flooding across Northern Europe. Impacts were particularly severe around the southern North Sea, including Lowestoft. Using the weather pattern approach, we identify Storm Xaver is associated with a cyclonic north-northwesterly with a low near southern Sweden (weather pattern 14 on the 5th) transitioning to an anticyclonic northwesterly with a high southwest of Ireland (weather pattern 13 on the 6th). In Lowestoft, the extreme storm surge threshold is 1.02m. Analysis shows a 2.7% chance that weather pattern 14 surpasses Lowestoft's warning threshold, while weather pattern 13 has a 0.6% chance (Figure 2). This indicates that, in the present climate, weather pattern 14 is an ‘at-risk’ weather pattern. Research by Perks et al. (2023) indicates that sea level change is a more significant driver of future coastal flood risk around the UK than changes in atmospheric circulation to 2050 and beyond. Using Storm Xaver as an example, and incorporating sea level rise projections from the UK Climate Projections 2018 (UKCP18), there is a 7.4% chance in 2050 and 14.6% by 2100 that weather pattern 14 would surpass Lowestoft's warning threshold under a low-emissions scenario (RCP2.6, consistent with strong global mitigation; Figure 2a). However, achieving RCP2.6 is increasingly considered ambitious. The UK Committee for Climate Change recommends that adaptation planning accounts for 2°C–4°C of global warming relative to pre-industrial levels. Under a high-emissions scenario (RCP8.5), we show this risk increases to 8.9% in 2050 and 50.3% in 2100 (Figure 2b). Understanding these risks is essential for informed decision-making and effective coastal adaptation. Coastal flooding poses a serious and evolving threat to the UK, as highlighted by the 1953 storm surge disaster and more recent events such as Storm Xaver. Flood risk arises from a combination of storm surges, tides, wind and waves, rainfall and rising sea levels. While flood defences and forecasting have greatly improved, climate change-driven sea level rise is likely to increase the frequency and severity of extreme coastal flooding during the 21st century, highlighting the importance of continued investment in adaptive flood risk management. The author would like to thank Freya Garry and Thomas Kilsby, who provided helpful comments on draft versions of the manuscript. Data sharing is not applicable to this article as no datasets were generated or analysed during the current study.