Climate change: Protecting against flood damage in Europe

At least 83％ of projected flood damage in Europe as a result of rising sea levels could be avoided by elevating dykes along approximately a third of Europe’s coastline, suggests a study in Nature Communications.

More than 200 million people live within 50km of the European coast, which stretches from the North-East Atlantic and the Baltic to the Mediterranean and Black Sea. With sea levels predicted to rise by as much as one metre along the European coastline by the end of the century, protecting coastal communities poses a serious challenge.

Michalis Vousdoukas and colleagues evaluated the costs and benefits of applying additional protection along the European coastline to protect against rising sea levels. The authors used a modelling framework to estimate present and future extreme sea levels based on projections of sea-level rise, waves, storm surges and tides under a high (RCP 8.5) and moderate (RCP 4.5) emissions scenario. From this, they were able to determine the land areas flooded and translate this into flood losses, which were then used in a cost-benefit analysis of raising dykes.

The authors found that the cost-to-benefit ratio of increased protection varied across Europe with costs outweighing the benefits along 68-76％ of the European coastline. However, in areas where population density was greater than 500 people per km2 the benefits tended to outweigh the costs. At a country level, Belgium had the highest percentage of coastline (85-95％) where benefits exceeded costs. This was followed by France (58-66％) and Italy (53-59％).