Climate change and demographic change in Germany
Within the nationwide vulnerability analysis that was implemented as part of the Network Vulnerability project, six different types of climate-change regions were identified (see Buth et al. 2015 and Figure 1) by means of cluster analysis. These types represent the regionally different climate impacts in the near future (2035). Climate signals (e.g. changes in mean temperature, precipitation, hot days and tropical nights) were used to identify these types. As shown in Figure 1, there are some regions that will heat up relatively more, while others will become more arid than others.
Demographic change in Germany encompasses both quantitative and qualitative changes in society (Kirk 2010). The diversity of demographic change in Germany is considerable: growing and shrinking cities are often found side by side, but all cities are going to have to deal with a significant increase in older cohorts, leading to different demands at city level. These elements of demographic change appear spatially diverse, as shown in Figure 2. In particular, the eastern parts of Germany are facing a decline in population. Bertelsmann Stiftung (2015; see also Figure 2) has identified nine different demographic types at city level, based on an analysis of 2,916 German cities using over 220 indicators.
Source: Bertelsmann Stiftung 2015.
Another project, DeKliWa,  provides an analysis of the impacts of demographic change (e.g. aging, shrinkage, and heterogeneity of the population) on the sensitivity of different types of urban structures with respect to climatic changes. This nationwide analysis was intended to provide arguments for integrated planning approaches to the two megatrends. One of the main objectives of the project was the identification of assessable combinations of climate change and demographic change in the near future (around 2035). The analysis had two main goals: to find representative case studies for each combination of climate and demographic change, and to identify spatial patterns. The methodology for the intersections followed the “parallel modeling approach” (Greiving et al. 2015), whereby climatic and demographic changes are modeled in parallel to achieve the best possible information on future climate-change impacts (see Greiving et al. 2018 and Figure 3). This methodology was applied at the intersection of representative data for climate change and demographic change, as shown in Figures 1 and 2.
The planning implications of intersecting changes
Our approach allowed us to draw conclusions about the specific socioeconomic characteristics of cities and regions affected by climate change, now and in the future (for more information on the analysis and detailed conclusions see Schulze-Dieckhoff et al. 2018). The two main conclusions regarding Germany that emerged from this study were as follows:
- cities with a growing population are more likely to be found in climate regions with higher levels of warming;
- cities with a significantly older and shrinking population are more likely to be found in regions with more arid climates.
These two conclusions lead to a number of interrelations, which should be targeted by adaptation actions.
Both climate change and demographic change lead to demands on future cities and regions. For example, cities with aging populations are likely to experience an emerging need to improve the accessibility of public spaces for disabled people, and to mitigate urban heat’s effect on people with cardiovascular disease. This is particularly urgent in growing regions, as the increasing population puts pressure on the usage of these areas. Decisions about the densification of vacant lots or the sealing of fresh-air corridors may—if climatic concerns are not granted a greater role in land development—lead to an intensification of urban heat-island effects. Even in shrinking regions, the absolute number of heat-sensitive seniors will increase in the medium term despite a decline in the total population (Schulze-Dieckhoff et al. 2018).
In cities and regions where the population is declining, there is great potential to adapt to climate change by dismantling or unsealing built-up areas, and by expanding and linking cold-air production areas and green corridors. Another opportunity is to encourage population to retreat from areas prone to fluvial or pluvial flooding, or endangered by alpine hazards such as landslides, rockfalls or avalanches.
In cities experiencing population growth, the risks are greater. For example, adaptation measures to promote age-appropriate mobility (e.g. lowering curbs) can influence climate impacts, such as surface runoff during a heavy rainfall event, increasing the potential for damage. It is therefore necessary to include information about potentially endangered areas in the planning and implementation of accessibility measures. Similarly, the allocation of social infrastructure, such as nursing homes and retirement homes, should not be conducted without first taking urban climate conditions into consideration. Already-stressed areas should be avoided as much as possible and facilities operated with appropriate shading and precautionary structural measures, for instance.
Challenges for spatial planning
As shown above, there are many interrelations between climate and social change which should be taken into account when dealing with climatic adaptation. Information about changes in the sensitivity of the population subject to future climate impacts is just as necessary as information about climate change itself. Only through a joint and integrated view can forward-looking adaptation measures be developed and implemented.
However, the national spatial visions for Germany—“Securing services of general interest,”  “Shaping climate change and energy transition,”  “Controlling and sustainably developing spatial functions,”  and “Strengthening competitiveness” —are not linked to one another. There is therefore a need to improve these visions in order to highlight interconnections between climate change and demographic change in Germany, and raise awareness of these intersections among regional and local planning actors. Through coordination at national policy level, regional and local adaptation strategies should become more integrative, capturing the emerging synergies and conflicts projected over space and time.
Spatial planning, because of its interdisciplinary character, is well placed to promote an integrated view of climate and demographic change. Spatial planning is always beset with uncertainties regarding population and environment. Its processes and instruments have the potential to deal with these uncertainties, yet they are often used in quite a traditional way that disregards the need for adaptive planning. Building flexible and adaptive structures becomes more important in the context of climate and demographic change. Elements like multifunctional usage of areas (e.g. using a park both for stormwater retention and as a ventilation channel) is an example of adaptive planning. Because of the durability of structures built based on spatial planning decisions (buildings are supposed to last for decades or more), it is especially necessary to work with different demographics and climate-change scenarios.
- Bertelsmann Stiftung. 2015. “Demographietypen”, Wegweiser Kommune.
- Buth, M., Kahlenborn, W., Savelsberg, J., Becker, N., Bubeck, P., Kabisch, S., Kind, C., Tempel, A., Tucci, F., Greiving, S., Fleischhauer, M., Lindner, C., Lückenkötter, J., Schonlau, M., Schmitt, H., Hurth, F., Othmer, F., Augustin, R., Becker, D., Abel, M., Bornemann, T., Steiner H., Zebisch, M., Schneiderbauer, S. and Kofler, C. 2015. Germany’s Vulnerability to Climate Change. Summary, “Climate Change” series, no. 24/2015, report produced by Adelphi (Berlin)/Plan + Risk Consult (Dortmund)/Eurac Research (Bolzano/Bozen) for the German Federal Environment Agency, Dessau-Roßlau: Umweltbundesamt (German Federal Environment Agency).
- Greiving, S., Arens, S., Becker, D., Fleischhauer, M. and Hurth, F. 2018. “Improving the Assessment of Potential and Actual Impacts of Climate Change and Extreme Events Through a Parallel Modeling of Climatic and Societal Changes at Different Scales”, Journal of Extreme Events, 12 April.
- Greiving, S., Zebisch, M., Schneiderbauer, S., Fleischauer, M., Lindner, C., Lückenkötter, J., Buth, M., Kahlenborn, W. and Schauser, I. 2015. “A consensus-based vulnerability assessment to climate change in Germany”, International Journal of Climate Change Strategies and Management, vol. 7, no. 3, pp. 306–326.
- Kirk, D. 2010. “Demographic Transition Theory”, Population Studies, vol. 50, pp. 361–387.
- Schulze-Dieckhoff, V., Becker, D., Wiechmann, T. and Greiving, S. 2018. “Spatial Patterns: Demographic Change and Climate Change in German Cities”, Raumforschung und Raumordnung, 17 April, Berlin/Heidelberg: Springer.