The sea level of the North Sea is rising, storm surges are increasing, and it rains more frequently and more heavily in winter. The water comes from everywhere and threatens the coastal regions of Northern Germany. Dykes alone are not enough to resist the consequences of climate change in the long term. Scientist Insa Meinke from the Helmholtz-Zentrum Hereon advocates new, sustainable measures for resilient coastal development. The new film production “North Sea Coast under Climate Change” from Hereon's North German Coastal and Climate Office shows where these can be applied.
Mrs. Meinke, how is Northern Germany affected by climate change?
In Northern Germany, climate change is affecting a region that has been protected from the water for a very long time. But adapting to climate change becomes more and more technically complex and expensive. What is often not known: Castal protection and inland drainage are connected and are both affected by climate change. Water comes from all sides and climate change means there is a need for action here. That is why we at the North German Coastal and Climate Office at the Helmholtz-Zentrum Hereon have published a new film. Entitled “North Sea coast under climate change”, it illustrates planning-relevant relationships between coastal protection, inland drainage and spatial planning on the German North Sea coast in a changing climate. The film serves as a basis for the necessary coordination processes among the public in Northern Germany. After all, in order to keep our North Sea coast habitable in the long term, we need to initiate effective long-term coastal development measures today.
Have you analyzed significant data on climate change in Northern Germany?
Yes, we have been analyzing climate - and water level data for Northern Germany for around 20 years, now. Some key findings regarding long-term changes have been confirmed and further consolidated: In addition to a long-term warming, winter precipitation has also increased in Northern Germany. Furthermore, a sea level rise is measurable on the North Sea coast and is around 20 centimetres within the last 100 years. This means that not only storm surges are higher, but drainage times are also shorter. The climate data shows a continuing increase in precipitation in the winter months, which could amount to around 40 percent in Northern Germany by the end of the century. All climate scenarios show that sea levels will continue to rise. If greenhouse gas emissions remain high, sea levels in the German Bight are expected to rise by 1.20 meters by 2100. In summary, it is becoming apparent that the need for drainage is increasing, while drainage times are shortening. An end to this trend is not in sight. This highlights the need for action to initiate new approaches for sustainable coastal development in addition to the expansion of existing protection measures.
What is the significance of storm surges?
Storm surges have always been part of the winter months in Northern Germany. When it storms outside and we hear storm surge warnings on the radio, we feel safe thanks to the dykes. After the devastating North Sea storm surge on February 16 and 17, 1962, the coastal protection along the entire North Sea coast was significantly upgraded. However, climate change is not only increasing storm surges, but also winter precipitation. The inland flooding in Lower Saxony last winter 2023/24 showed what consequences this can have: Weeks of heavy rain coincided with an active storm surge season, pushing drainage to its technical limits. Large parts of northern Lower Saxony were under water. This makes it clear that the various problem areas need to be linked in order to find solutions for a long-term habitable coast.
Could such floods occur more frequently in the future?
Yes, such unfavorable constellations with an increased risk of inland flooding could occur more frequently and more intensively as a result of climate change. This is because the increase in winter precipitation will increase the need for drainage, but at the same time the rise in sea level will make it more difficult to drain the dyked areas. In addition, high storm surges such as the one on February 16/17, 1962 could occur statistically every 5 to 10 years at the end of the century if greenhouse gas emissions remain high, thus placing a greater burden on coastal protection structures. As sea levels will continue to rise for many centuries to come, we need to initiate effective measures now in addition to expanding coastal protection and inland drainage.
What advice would you give to decision-makers from politics, authorities and coastal protection?
It is more important than ever to make better use of natural processes again, for example, there should be opportunities to partially open the dykes and flood the areas behind them in a controlled manner so that sediments can settle and areas can grow, again. Buildings and infrastructure should also be adapted to the water and new utilization concepts developed. However, sustainable coastal development is not just a technical task, but also a social process. It requires the linking of various policy and planning areas, taking into account different interests. Our films serve as a scientific basis for the necessary coordination process in society. The film “North Sea Coast under Climate Change”, explains the essential interrelationships of the complex interdependencies of the North Sea coast in climate change.