- Coastal areas are naturally exposed to coastal flooding. However, the exposure to coastal storm surge events varies considerably between coastal regions.
- Increasing inundation depths due to coastal flooding affect regions around all six European seas but accumulate around the North Sea, especially along the Dutch-German coastline.
- In countries where also hinterland regions are affected, storm surge events can pose a challenge to be tackled on national and cross-border level. Necessary infrastructures comprise modern and comprehensive technical and building infrastructures as well as appropriate planning instruments.
Observations for policy
Coastal areas are vulnerable to climate change as they are exposed to coastal flooding. However, maximum inundation depth forecasts for 2100 indicate that the exposure to coastal storm surge events varies considerably between coastal areas. Changes in inundation depths will have marginal negative or even no impact for most coastal regions, whereas some regions have to expect severe changes, i.e. will face a higher inundation level through coastal storm surges.
Negative impacts of coastal flooding especially occur in estuary, densely populated coastal, below-sea-level, and harbour areas. They affect regions around all six European seas but are concentrated around the North Sea, i.e. they especially occur along the Dutch-German coastline but also in Denmark, Belgium, France and the United Kingdom.
Infrastructures that are related to coastal flooding include extensive dyke systems and retention areas, as well as warning systems, new building and housing technologies, and related planning instruments. Adequate and developed infrastructures are essential to protect affected regions from challenges resulting from both an increasing number and increasing intensity of storm surge events.
Sea-level rise is a first level effect triggered by climate change, i.e. by global warming. The Territorial Agenda 2020 highlights that the impacts of climate change vary considerably across Europe, both in terms of types of impacts and of degrees of vulnerability. Correspondingly, the Europe 2020 Strategy calls for investments in low-carbon technologies that will contribute to climate change mitigation, and in R&D and innovation policy that help to fully exploit the potentials of new technologies such as carbon storage, for example.
The above measures focus on mitigation whereas European Cohesion Policy also acknowledges the relevance of measures aiming for adaptation to climate change, and risk prevention and management. In order to ensure the regional resilience to climate change, investments are supposed to address specific regional risks and consider the regional exposure to different impacts of climate change. This can also include new disaster management systems, especially for densely populated regions like seaward urban areas and harbour cities. The Sixth Cohesion Report emphasises that regions differ in their capacity to adapt to climate change, and that the regional vulnerability to climate change highly depends on the adaptive capacity.
The map identifies European regions that will be exposed to coastal storm surge events due to increasing inundation depths of storm surge events. By 2100 depths will increase in these regions as a result of a one meter sea-level rise. In total, Southern, Eastern and Northern (except Iceland and Denmark) Europe seem to be less impacted than countries in Western and Northwest Europe. The highest concentration of regions with medium to high impacts can be found around the North Sea, especially along the Belgian, Dutch and German coastlines, but also in Northern France, Denmark and Western UK. Around the North Sea, one also observes that a higher number of regions without a coastline are exposed to storm surges. This especially concerns Dutch regions located below sea-level, but also several German and Belgian hinterland regions. In these countries, coastal storm surges pose a challenge to be tackled on national and cross-border level.
Beyond the North Sea as a European hotspot, local hotspots showing the highest increases in inundation depths by 2100 are located in Northeast Italy (Veneto region) and Eastern Romania (Tulcea region), where the Danube Delta and its extensive biosphere reserve are located.
Coastal areas are obviously more exposed to storm surges. Besides the North Sea, changes in inundation depth will affect regions in different European countries around all European seas, such as the region of Lisbon, Western France, Northwest Ireland and Iceland with regards to the Atlantic and Arctic Ocean, two regions in Southern France at the Mediterranean Sea, four regions in Northeast Italy at the Adriatic coast, and two Romanian regions at the Black Sea. In the Baltic Sea, Northeast German, Northwest Polish and Danish regions will be affected by such storm surges.
Concepts and methods
Storm surge heights of a 100-year return event were derived from DIVA projections (Dynamic Interactive Vulnerability Assessment). In order to incorporate climate change, it was assumed that due to sea-level rise these storm surge heights would increase by one meter. Regional differences in sea-level rise exist but their development by 2100 could not be estimated yet. Therefore, a uniform one meter sea-level rise was presumed. Consequently, based on a global digital elevation model drawn from the Hydro1k database, areas that would be then inundated due to coastal flooding were delineated and changes in inundation depths by 2100 due to sea-level rise were calculated.