Climate change has a decisive influence on the use to which spaces will be put in the future. It can influence the use of space directly, as in the case of a floodplain, or indirectly, as through changes in water availability. Climate change also brings with it additional demands on space and land use.
The task of spatial planning is to record the various demands on space resulting from a wide range of human activities and needs, to weigh them up against each other and to coordinate the implementation of the results. Spatial planning controls on a large scale where in space which uses are located (e. g. settlements, transport infrastructures, recreational areas, agricultural production areas).
According to the German Spatial Planning Act (ROG), spatial significance is defined as the use of space or the influence on the spatial development or function of an area. Climate change and its impacts are highly spatially significant. The impacts potentially influence all areas of spatial development and a variety of spatial uses. They affect the activities, uses and demands of many economic sectors (e. g. agriculture, forestry, tourism), the spatial demands of a wide range of population groups, as well as natural systems and their ecosystem services (e. g. protective effect of forests, provision of water, production of food). Priority climate impacts with spatial planning relevance are in particular: Flood risks in river basins, dangers from sea-level rise and increased storm surge levels in coastal regions, stresses from heat in settlement areas, impairment of water supply and water availability due to prolonged dry periods and threats to biodiversity.
Flood risks: Depending on regional and local conditions, floods, inundations, flash floods and landslides may increase in river basins as a result of extreme precipitation. This increases the risk of damage to settlement areas and their infrastructures. An increase in damage from inland flooding and flash floods is also due to the expansion of settlement areas and post-densification and a corresponding increase in the existing values of infrastructures and buildings in floodplains. Land at risk is no longer available for sensitive uses due to more frequent flooding.
Sea level rise and storm surges: Due to sea level rise, storm surges could occur more frequently in the future with high water levels. The consequences are coastal flooding, reduction of wetlands, coastal erosion and increasing salinisation of agricultural land. Coastal erosion results in more frequent break-off on steep coasts and removal of material on flat coasts, accelerating coastal retreat. Flooding can damage coastal housing and infrastructure and threaten populations in low-lying coastal areas. Other consequences include saltwater intrusion into groundwater and agricultural soils, which can render irrigated cropland and drinking water reservoirs unusable as a consequence.
Extreme temperatures and heat waves: Higher extreme temperatures, less cooling at night, as well as more frequent and more intense periods of heat, combined with dense building development, a high proportion of sealed surfaces, too little green space, and waste heat from industry, buildings and traffic, increase the formation of heat islands in inner cities. This can lead to high heat stress for urban residents, with consequences for their well-being and health. This applies in particular to the elderly, people in need of care and sick people, as well as small children and pregnant women. Heat, combined with drought, can also affect green spaces and protected areas and thus biodiversity in urban areas.
Water supply and availability: Rising temperatures and changing precipitation conditions can have a fundamental impact on the quantity of groundwater resources. Thus, in the course of climate change, a decrease in groundwater recharge is to be expected. With more frequent dry periods, areas could be increasingly affected by temporary water shortages in the future. If the usable water resources are restricted, this will affect almost all spatial functions (e. g. settlements, open spaces, transport, water and energy infrastructures). In addition, it can be assumed that more frequent heavy rainfall events may endanger the quality of drinking water through the contamination of near-surface sources, which in turn requires additional effort for drinking water supply.
Threat to biodiversity: From the perspective of spatial planning, the shifting of vegetation zones, range shifts of species and changes in habitats due to climate change play an important role for the concerns of biodiversity and nature conservation. Changes in the geographical distribution of species (e.g. spread of warmth-loving species, decline of cold-tolerant species, displacement by immigrant species) have consequences for the species inventory, the species composition and thus for the structure of habitats and entire ecosystems. Particularly endangered habitats are forests, wetlands (e. g. bogs due to increasing summer drought, coastal habitats (e. g. salt marshes due to higher water levels) and protected areas. The change in the natural potential of protected areas due to climate change will have an impact on the protection and conservation objectives.
The increasing discrepancy between the demand for space and the availability of space, in particular the shortage of available land, leads us to expect increasing conflicts over space and land use as a result of the consequences of climate change. Settlement development, commerce, tourism, coastal protection and nature conservation, drinking water supply, agriculture as well as forms of regenerative energy production for climate protection that depend on the use of land (e.g. solar open space plants, wind farms, biomass cultivation) are in competition for land. For example, in water management, problems result from increasingly competing groundwater withdrawals during dry periods (agriculture vs. drinking water supply), and problems arise in creating new retention areas that could be used as floodplains in the event of an inland flood (e. g. agriculture vs. flood control).
Spatial planning is characterised by a high degree of connectivity with other fields of action that occupy land or indirectly influence the use of space. Cross-relationships exist in particular with the field of action of the economy (e.g. designation of suitable sites for industry, commerce and service facilities), the energy industry (e.g. designation of wind power sites), transport planning (e.g. expansion of transport infrastructure), nature conservation (e.g. designation of protected areas) and water management (e.g. securing flood plains). There is also often a close connection between planning and health aspects. For example, the urban structure, i.e. the dimensioning and design of open spaces, streets, built-up areas and individual buildings, has an influence on summer heat generation and ventilation and thus on the well-being and health of the urban population.
Due to its cross-sectional character, spatial planning plays a decisive role in shaping the respective living environment, i.e. the conditions for living, working and leisure activities. Consequences of climate change can be mitigated by using space in a way that is as climate-adapted as possible.
