For some years now, we have been experiencing long, dry heatwaves in Wiesbaden in the summer. They put a strain on human health. Elderly people, small children and the sick are particularly affected, as media reports on retirement homes, clinics and day care centers have shown. However, the effects can also be felt in many other areas. Road surfaces, for example, were damaged by so-called "blow ups" due to the heating of the asphalt. Agriculture suffered considerable crop losses due to the prolonged drought. In the weakened urban forest, clear-cut areas are on the increase due to bark beetle infestation in spruce stands. There was also an increase in forest and field fires due to the drought. Low water levels in the Rhine and Main became a problem for wildlife, but also for shipping and thus for the economy, and at the same time there was an increase in heavy rainfall events and flooding. All of this shows that climate change affects the most diverse areas of life.

Are we only dealing with extreme weather periods or a trend that is becoming more permanent and can be expected to cause even greater stress in the future? There is much to suggest the latter. The forecasts of the German Weather Service as part of the cross-state and cross-city project "Climate Change in Practice" (KLIMPRAX for short) have confirmed this for Wiesbaden and Mainz.

This poses major challenges for the city and its residents - especially in the areas of housing and mobility.

The task of sustainable urban development is to sustainably secure and improve the quality of life. To this end, green spaces and trees that traditionally characterize our cityscape must be permanently preserved and additional ones created in the sense of a double inner development.

At the same time, Wiesbaden also needs considerably more living space. The aim must be to create healthy living and working conditions in existing and new development areas. Existing neighborhoods must not be allowed to deteriorate under any circumstances.

Urban densification creates living space, shortens distances and protects the open countryside. At the same time, however, this also increases the risk of heat islands and flooding. A dilemma that we must solve.

The KLIMPRAX project has succeeded in describing the predicted effects of climate change for the cities of Wiesbaden and Mainz in more detail and identifying the affected fields of action. From this, guiding principles and visions must be derived that show compatible and sustainable utilization concepts. The results of the project provide important information in this regard:

Using the model municipalities of Wiesbaden and Mainz as examples, administrative action and planning practice on urban climate were examined and recommendations for action were derived in the form of an action guide for municipalities. The guide contains recommendations for the following levels of action: "Awareness and motivation", "Technical principles", "Overall strategies" and "Cooperation and coordination".

In addition, an action guideline for municipal climate adaptation was developed for all Hessian municipalities for the fields of action "Heat and health". This contains a catalog for municipal (urban development) planning with concrete measures and implementation proposals.

The results of the KLIMPRAX Stadtklima project have been published on the website of the Climate Change Center in the form of a report and a brochure.

As part of the KLIMPRAX project, the German Weather Service has carried out a "Model-based analysis of the urban climate as a basis for climate adaptation using the example of Wiesbaden and Mainz". It describes the current climate and projects the future climate for both cities. The models show a significant increase in summer days, hot days and tropical nights up to the year 2060. The warming will be greater in the Rhine Valley than in the Taunus. The warming will also be more noticeable in built-up areas than in contiguous areas without buildings. This supports the assumption that there will be greater warming in the already polluted areas of cities and urban districts than in the surrounding countryside. The increase in tropical nights is therefore highest in built-up areas and along the Rhine, while it is lower in the forest-free and undeveloped areas of the valleys. This means that the function of so-called cold air corridors, which channel cooler air into overheated areas, will become even more important in the future.

Based on this, intersections with demographic and socio-economic parameters were carried out. In this way, it was determined which population groups will be particularly affected by the urban overheating that will occur even more frequently in the future. At the same time, measures were developed to protect the affected population.