Climate change and its effects on our habitat are becoming increasingly clear year after year. In addition to measures to decarbonise transport, industry and energy supply, infrastructural adjustments are also needed to respond to the consequences of global warming. In the “Grüne Zentren” project (Green Centres), a team led by Eva Schwab from the Institute of Urbanism, together with the Technical Office for Landscape Planning and Landscape Ecology led by graduate engineer Maria Baumgartner, analysed the effects of climate change that have already occurred in the Styrian Central Region consisting of Graz, Greater Graz and Voitsberg and, on the basis of the analysis, have produced a guide called Climate-Smart Green Spaces for municipalities. The guide provides suggestions for more sustainable spatial planning and shows, among other things, green-blue elements (plants, trees or green spaces and water areas or bodies of water) that can help to align future land use with the expected climate-related needs. The sponsor for this research was the regional management of the Styrian central region.
Analysis before measures
“In order for municipalities to best prepare for the effects of climate change, a data-based inventory of how the changing climate has made itself felt was first needed. The consequences affect each community differently, in one it is far too dry, in another there is too much precipitation and others experience both alternately. This is due to the respective topography, the soil conditions and the degree of sealing. A precise regional analysis was therefore essential in order to provide the right orientation,” says Eva Schwab.
In its analysis, the team recorded and overlaid mapped data on temperature development, sealing, heavy rainfall, flow paths, landslides, soil types and flooding and, based on this, identified the regional needs for green-blue infrastructure. These are types of infrastructure that utilise plants and water in such a way that residential and commercial areas are better equipped to cope with extreme weather conditions. These include green spaces or green roofs and façades as well as ponds, lakes, canals and areas such as large meadows where water can collect during heavy rainfall. In addition to the data analysis, community interviews were conducted to identify specific effects and existing measures.
Broken down to individual areas of the Styrian central region, the researchers found in their analysis that the southern part of the region is increasingly affected by heat development and dry periods. Graz and the neighbouring areas to the south increasingly form heat islands due to soil sealing, which leads to heat waves during the summer months. The south-western part of the region is considered to be particularly prone to severe weather, which, in combination with increasing soil sealing, raises the risk of flooding during heavy rainfall events. In the Styrian hill country to the west and east of Graz, there is a risk of landslides due to the topography and soil conditions.
Rethinking needed
In order to minimise these effects as much as possible, new approaches need to be taken in spatial planning and land use. In addition to soil sealing, it is particularly dried-out soils that are responsible for heavy rainfall no longer being able to be absorbed by the soil. Infrastructure adjustments, such as the expansion of drainage systems and retention basins as well as improved early warning systems, are therefore an important countermeasure. Natural floodplains and the rewilding of riverbanks would further increase the absorption capacity of water bodies. One of the most important aspects is sustainable land use, which keeps land sealing to a minimum.
The issue of sealing particularly affects growing municipalities, which is why the “örtliche Entwicklungskonzept” (Local Development Plan (LDP)) presented in the guide is primarily intended to sensitise them and encourage them to rethink their approach. Quote from the guide: “The LDP offers the opportunity to plan the development of the municipality for the next 15 years. It is strategically the best and most important way of thinking about green-blue infrastructure on a truly large scale and anchoring landscape and green space protection in the municipality at the highest level with objectives and measures. Here, for example, settlement boundaries, free zones, suitability zones and priority zones can be defined. Specifications can be made for the desired development of buildings, as well as natural and cultural spaces, and for the design of the road network in the sense of a pedestrian- and cyclist-friendly place of short distances.” One focus here should also be on the development of the town centres in such a way that the outskirts are not further sealed while the town centre becomes increasingly extinct.
In addition, the researchers also present highly targeted measures that address the respective climatic conditions of the communities. For areas with extended dry periods, the research team recommends water reservoirs and efficient irrigation systems for water supply in agriculture. The cultivation of drought-resistant plants and the improvement of soil quality can also reduce the effects of drought. In urban areas, urban planning and green space management help to avoid heat islands. At the same time, the promotion of natural water retention basins and floodplains in accordance with the sponge-city principle can minimise the impact of heavy rainfall events. In addition to geotechnical investigations and early warning systems, the researchers recommend the use of drainage and deep-rooted planting to reduce erosion and increase the stability of the subsoil in the event of landslides.
Keeping the impact of climate change as low as possible
However, it is up to the municipalities themselves to implement all the recommendations, and the project team is aware that this can be a challenge. Nevertheless, the team members are convinced that implementation will not only serve adaptation to climate change, but also promote the vitality of the town centres and active mobility in the town and makes economic sense. If there are any doubts, the guide also offers a fact check on the most common “green myths” to dispel objections such as “We can’t afford it anyway” or “There’s no room for planting”.
“We are increasingly feeling the effects of man-made climate change. In addition to measures to keep it within limits, we want to use the proposed strategies to help minimise its consequences,” says Eva Schwab. “We also strongly advocate protecting and restoring natural ecosystems and sensitising the population to the effects of climate change. This also includes promoting water-saving measures to protect against drought and heat.”
This article is part of the TU Graz Dossier "Cities in a Changing Climate". You can find further Dossiers at www.tugraz.at/en/go/dossiers
