CPA - Klimabeweisgebiete - Vergleich der Auswirkungen des Klimawandels auf die Nordseeländer | Umweltbundesamt

"Inland flooding: Exemplary remarkable floods in German North Sea tributaries were floods of the Rhine (1993, 1995), the Odra (1997), and the Elbe Rivers (2002). Observations only partly show slight increases in flood intensity and flood probability. However, most of the identified trends are statistically not significant using all historically available gauge data (Bormann et al., 2008). In contrast, Petrow and Merz (2009) identified regionally significant trends in the second half of the 20th century in German river basins. Projections by the German Federal Government (Bundesregierung, 2008) assume an increasing flood risk in winter due to lighter snow fall as well as snow cover and strengthened direct runoff generation mechanisms. In northern Germany there is currently no concrete strategy available to adapt flood protection to climate change conditions. In comparison, in southern Germany (Bavaria and Baden-Württemberg) so called 'climate change adaptation factors' have been introduced to adapt design floods to climate change conditions; thus, to take into account the non-stationary behaviour of hydrological time series, design floods are multiplied by factors depending on the flood probability, e.g., 15% for a hundred year flood, 8% for a 200 year flood, and 3% for a 500 year flood (Katzenberger, 2008; LfU BW, 2005)." (p. 40)

"Coastal flooding: In Lower Saxony, sea dikes are assumed to be safe, assuming that there is no risk 'behind' the dike with respect to a potential dike breach. As mentioned above, projections of future sea level rise in Lower Saxony are based on the global projections of the IPCC (2007), compared to a linear extrapolation of the changes observed in the past (NLWKN, 2007). This results in an expected sea level rise of 18 to 59 cm by 2100 (NLWKN, 2007). The current strategy therefore is to increase the height of dikes by the expected climate change induced sea level rise to further ensure safety." (p. 16)
"In the past century, statistically significant increasing trends have been observed for temperature and sea level while for many other variables such as precipitation the underlying variability is very large. For this reason detectable trends are not statistically significant. With respect to model based climate projections, there is similarly a clear indication of a rise in temperature. Precipitation is expected to change as well although models tend to disagree even in the direction change for summer precipitation in northern Germany (IPCC, 2007). Sea level rise is expected to continue further in future, thus increasing the risk for coastal areas in particular." (p. 40)