Interacting cities and surroundings – the impact of strategic spatial planning on the local climate (INTERFERE)

The consequences of the human made climate change are omnipresent – the recent years were marked by droughts, extreme and deadly precipitation events, extreme hot temperature records, wildfires and overall warmer than average temperatures. Especially the warmer summer temperatures are further increased within (densely) built areas due to the different characteristics of sealed versus unsealed areas. The awareness of this so-called urban heat island (UHI) effect has increased over the past as has the understanding of the negative impacts due to soil sealing. Nevertheless, the trend of urban sprawling is undamped that is also seen by the city of Graz and which relates to sealing green areas for infrastructure (roads, rail network) and so far, mostly single-family homes. Yet, this process has an impact on the local (micro-) climate, as well as on the climate of the surrounding areas or adjacent cities, which has not been investigated in detail so far. Thus, the key focus of INTERFERE is not the urban area as usual, but the developments in the surroundings of the city, the suburbs and the urban sprawl. The densification and sealing in this area will highly impacts the local micro-climate but might additionally influence the whole urban area including the city centre. Therefore, the following aspects are analysed: • interactions and impact of the growing and densification of the suburbs (residential areas, shopping areas, roads) surrounding Graz on the suburbs’ local micro-climate conditions and on the city’s climate under different climate conditions (current, future scenarios) • the ability of different models (regional climate model (RCM), RCM with specific urban model coupled, urban climate model, microclimate model) to simulate the interactions mentioned above at the different spatial scales (several meters to some kilometers) • Quantitative information on the adaptive potential of green and blue infrastructure measures at different scales. • Assessing the potential of strategic spatial planning to reduce soil sealing and to strengthen, secure und enhance ecosystem services relevant for the local climate and people. The quantitative analysis of the impact of urban sprawling and the potential of strategic spatial planning is analysed by defining future spatial development concepts based on local and regional expertise with respect to spatial planning concepts, including mobility and zoning plans as well as an active discussion with local and regional stakeholders. These development plans are then translated into the chosen models to quantify the impact of planning concepts on the local (micro-) climate within the suburbs / surroundings of Graz as well as on the (micro-)climate of Graz during a heatwave. The conclusions drawn within INTERFERE are communicated to the relevant stakeholders to ensure a sustainable impact.