Heat for two weeks on vacation in Andalusia or Sicily – wonderful. But a whole summer in Germany, in everyday life, in big cities? What may seem a horror to many people could soon be a recurring reality. Scientists like the Potsdam climate researcher Hans Joachim Schellnhuber are already warning of a hot period in view of climate change. How do cities in Germany adapt? Three examples:
Karlsruhe: The city is located in Germany’s warmest corner, has been dealing with the topic for a long time, but has a problem right in the center. After years of construction work on a tram tunnel, the market square is currently being restored. However, as a stone desert without trees – according to plans by the architect Friedrich Weinbrenner, 200 years old.
The city not only wants to preserve the historical character of the square. Because of the underground stop and many lines close below the surface, no trees could be planted, says Heike Dederer from the city planning office. After all, light stone slabs should soon replace the heat-shimmering asphalt pavement.
Water features on an area of 180 square meters and 31 nozzles integrated into the flooring with water jets up to 1.5 meters high should contribute to a pleasant climate, emphasizes Mayor Frank Mentrup (SPD). “I am convinced that young and old will gladly accept this offer in summers like this one.”
In the new pedestrian zone, the city wants to plant twice as many trees as originally planned. Maple or columnar oak are no longer the first choice, but the hackberry tree, which can withstand heat and drought better.
According to Mentrup’s information, Karlsruhe will have to reckon with a temperature increase of at least four degrees in the next 20 years. “That means unequivocally: We have to set the course now to make the climate in the city bearable – also for future generations,” he said recently.
In the Wilhelminian style residential quarters, planner Dederer and her team concentrate on the courtyards inside the closed apartment blocks. There were many sheds and built-up areas there over the years. There is an urgent need to create green spaces here again. “Evaporative cooling is the magic word,” says Dederer.
The new Southeast district shows how things can be done better. The multi-storey development is always open on at least one side. All flat roofs are green and a new park with a lake forms a green axis along the main road towards the city center. The facades are light in order to heat up less. White plaster reflects significantly more sunlight than dark brick, for example.
Tram lines can also serve as ventilation axes. They should, wherever possible, become green lawns. But these have to be watered to be effective. “Maybe you just hang an irrigation cart on the last tram of the day,” suggests Dederer.