Sea Level Rise - what does this imply for Germany?

Our parliamentary breakfast on sea level rise, directed by Dr. Jan-Niclas Gesenhues (Alliance 90/The Greens, GRÜNE), took place on October 11, 2023. The event was attended by 28 people in total. These included eleven members of the German Parliament (members of SPD, CDU/CSU and Alliance 90/The Greens, GRÜNE) and employees from SPD, CDU/CSU, Alliance 90/The Greens, GRÜNE and FDP.

Prof. Dr. Karin Lochte (UN-Ozeandekaden Komitee Deutschland, former AWI director), who held a short key-note lecture, pointed out that sea level rise is a slow, gradual development, which also offers an opportunity for adaptation. Sea level rise is a global and high risk, which is associated with an increasing number of storm surges. This threatens, among other things, drinking water supplies and biodiversity. Various Helmholtz centers are working on the important topic of “sea level rise” as part of the joint research program “Changing Earth - Sustaining our Future”.

First, Dr. Ingo Sasgen (Alfred Wegener Institute Helmholtz Center for Polar and Marine Research (AWI)) covered the polar perspective of the global risk. The decrease in ice masses can be measured with satellite data at relatively high resolution and is progressing faster than predicted by climate projections. The question is not if, but when we will have a certain sea level rise. Through climate action, we can influence the future sea level rise.

Another problem that adds to sea level rise is land subsidence. In the next presentation, Dr. Tilo Schöne (Helmholtz Center Potsdam - German Research Center for Geosciences GFZ) made aware of this problem. Sea level varies in different places across the world and particularly affects smaller island states. Jakarta - the ‘sinking city’ - now lies with 40% of the city area below sea level. In 2011, 26 cm of land subsidence was recorded in a single year. Coastal erosion and limited coastal protection, for example because dikes cannot be built on reefs, are key problems in these island states.

But rising sea levels also have an impact on the German coasts. According to Dr. Insa Meinke (North German Coastal and Climate Office; Helmholtz Center Hereon) and Dr. Ralf Weisse (Helmholtz Center Hereon), the increase of sea level in Cuxhaven in the last 100 years was 20 cm and in Warnemünde 13 cm, which is comparable to the global average. The precautionary measure for construction measures in coastal protection until 2100 is currently 1 m. Regional scenarios predict an increase of 30 - 120 cm in Cuxhaven by 2100. Erosion increases the threat to coastal protection and also affects drinking water supply. In addition, the overloading of the inland drainage system is a problem. Storm surges will be higher, more frequent and longer in the future, which will increase the area which has to be protected and requires more intensive protection measures.

Following the presentations, questions and comments from the participants on i) the influence of tourism on the North Sea coastal region, ii) storm formation, iii) measures to support small island states, and iv) political requirements were answered by the experts. All participants and anyone who is interested is invited to contact our Helmholtz experts further on the topic of sea level rise. Key messages and contact info from our experts can be found on our fact sheet. The parliamentary event was organized by SynCom, Climate Office at AWI, German Arctic Office, REKLIM and North German Coastal and Climate Office.