Background and Goals
The Intergovernmental Panel on Climate Change (IPCC) at the United Nations expects that mean global temperatures will increase significantly in the coming decades due to the anthropogenic greenhouse effect. This will involve a significant change in the global climate. This climate change will have an impact on the regional water balance. However, reliable information about the consequences of climate change at national level has not yet been available. There has been a lack of data and facts about how to estimate and assess the future development of the water balance and its components. The project therefore analyses the effects of climate change on the water balance and how the changes in the water balance affect the different areas of water management.
With this cooperation project, the states of Baden-Württemberg and Bavaria, in conjunction with the German Meteorological Office, have set the objective of coming up with possible effects of climate change on the water balance of Southern German river areas, highlighting consequences and deriving recommendations for action. First of all, the analysis and assessment of meteorological and hydrological data from the 20th Century provided the basis for estimating climate changes that have already occurred. The development of innovative regional climate scenarios allowed conclusions about regional climate effects to be obtained in Germany for the first time. Transferring these results to the water balance models in the different states enables conclusions to be drawn about the development of flood occurrences in the next 50 years. Therefore, the objective is to assess future developments in the water balance, to identify possible hazards and risks, to define forward-looking and sustainable water management strategies and concepts, and to promote longer-term inter-regional and interdisciplinary cooperation.
- Rhineland Palatinate
- Alp and North Bavarian hills
- Erz Mountains, Thuringian Forest and Bavarian Forest
- West German lowland bay
Steps in the process of adaptation to climate change
Step 1: Understand and describe climate change
Regional climate modelling based on statistical methods, statistical dynamic methods and regional dynamic climate models, derived from the ECHAM4 global climate model and the A1 and B2 (IPCC) emission scenarios, in conjunction with the KLARA project.
Average annual temperature increase of 1.7°C, changed frequency of temperature threshold days, changes in precipitation volume and distribution (including snow), changes in the general weather situation
- River flooding
- Altered rainfall patterns
- Higher average temperatures
- Low water
- Dry periods
Simulation of the period 2021-2050
Step 2a: Identify and assess risks - climate effects and impact
The project studies the climate effects for the water balance that can result from changes in drainage, in leaching and in evaporation rates. In addition, changes in ground moisture and groundwater regeneration, as well as extreme flood drainage will be analysed.
Furthermore, climate monitoring will be carried out with the objective of documenting promptly and at regular intervals the long-term behaviour of selected hydrological and hydro-meteorological variables that could provide indications of changes in the climate in Southern Germany. The changes in the meteorological variables of temperature and precipitation identified in 2008, in conjunction with the changes in flood drainage, are viewed as clear effects of the climate change that has been detectable for several decades. Previous simulation calculations using regional climate scenarios also indicate that a further intensification of flooding can be expected in the region in the future.
The results of the climate monitoring clearly show that the effects of global climate change have been noticeable in Southern Germany for a long time and, in some cases, have become significantly more intense in recent years. Initially, these are the sharp temperature increase and the change in precipitation patterns. Both of these have a significant effect on the regional water cycle and, based on current knowledge, lead to an increase in the flood risk and also to a temporary reduction in water availability when occurring in conjunction with longer, hot and dry periods.
Step 2b: Identify and assess risks - Vulnerability, risks and chances
A checklist to determine vulnerability will be created, but will focus exclusively on susceptibility to damage (not adaptation capacity). Thus, in this project vulnerability is used in the sense of susceptibility to flooding. The physical effects that can be derived from hydraulic conditions form the basis for analysis of the socio-economic, ecological and socio-cultural impact.
The states of Baden-Württemberg and Bavaria are the first in Germany to implement a climate change factor in the assessment of new technical flood protection buildings. For example, the forecast increase in flood drainage can already be incorporated into planning.
Step 3: Develop and compare measures
As part of the response to climate change, adaptation strategies for flood protection will be developed. The objective is to develop action strategies and concepts for water management, which incorporate a climate change factor into the assessment of flood protection facilities.
- 2021–2050 (near future)
Baden-Württemberg, Bavaria, German National Meteorological Service
State Agency for Environment, Measurements and Nature Conservation Baden- Württemberg (LUBW): unit 43, Hydrology and flood prediction as well as the Bavarian Land Office for the Environment (LfU): unit 81 Climate Change, Climatic Consequences
Cooperation project between the Länder of Baden-Württemberg (Ministry of the Environment of Baden-Württemberg, Water and Soil Department) and Bavaria (Bavarian State Ministry of the Environment and Public Health , Water Management Department) as well as the German National Meteorological Service (DWD, Hydrometeorology Department);
the federal state of Rhineland-Palatinate has also been involved since the beginning of 2007
State Agency for Environment, Measurements and Nature Conservation Baden- Württemberg (LUBW)