14.07.2022, Spanien, Sevilla: Eine Frau kühlt sich in einem Park ab. Die derzeitige Gluthitze-Periode in Spanien soll mindestens bis zum kommenden Dienstag anhalten. Foto: Rosa Veiga/Europapress/dpa +++ dpa-Bildfunk +++

If the occasion were not so worrying, one could speak of ideal timing. While the heat and drought are once again urging the public and politicians to take action, a new volume by Bernd W. Krupka was published in mid-July, which, in addition to roof and façade greening, is primarily dedicated to the further development of urban vegetation techniques.

The cities must finally be better protected against high temperatures and heavy rain. Almost two decades after the first periods of sweltering heat and heavy rain events, the time has come. Also in Germany. However, considerations such as those of the Federal Environment Agency alone will not do the trick. “We have to rebuild our cities in order to be able to live with climate change,” President Dirk Messner told the German Press Agency. “This includes, above all, a lot more greenery in the cities. It cools you down significantly.” Krupka wrote down what that could look like in concrete terms. He agrees with Messner that areas such as parking lots, streets and paved squares in large cities should be unsealed. In addition, the green roof expert has arcades as green tunnels in urban space, green wall systems, extensive green roofs, vegetation mats for adjacent traffic areas, such as traffic islands and lane dividing strips. To name just a few examples. These would be wonderful jobs for functioning parks departments.

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“With the federal program for adapting urban areas to climate change, we are supporting cities and communities in the preservation and development of green and open spaces,” said Federal Minister for Building and Urban Development Klara Geywitz on July 19 in Potsdam. “Where there is greenery and water, the environment is cooler.” The federal government wants to take on up to 85 percent of the eligible costs.

The author has not concerned himself with the costs of his urban ecological application examples – and he does not have to: In view of the dramatic changes that are taking place around us on land, in the water and in the air, money is (almost) irrelevant more.

On July 21, Leif Miller, national director of the Nature Conservation Union (Nabu), criticized the fact that there was still no real trend reversal in land use. “The federal government is miles away from meeting its self-imposed goal of a maximum of 30 hectares per day of land use by 2030,” Miller said. For example, rows of huge logistics properties would be placed in the landscape. The sealing would cut up habitats, affect the groundwater balance and emit more CO2, since new settlements and traffic areas cause more traffic. In cities, districts overheat because the evaporative cooling of unsealed surfaces is missing. According to the Federal Environment Agency, around 45 percent of settlement and traffic areas in Germany are sealed. They are built on, concreted, asphalted, paved or sealed airtight and watertight with foils.

The aim of the book is to provide assistance in planning and implementing the revitalization of densely populated urban areas and adapting to climate change. Krupka’s basic idea: to design urban nature as a demonstrably efficient urban ecosystem for the future. “This ecosystem consists of a network of vital urban spaces,” the expert suggests: “The basic components of soil, water and vegetation are intended to achieve lasting, climate-effective and health-promoting effects.” is about his favorite topic: “The visible consequences of climate change in the shifting of the seasons have a stronger effect on the extreme planting location on the roof than on ground-based greening.” Unfortunately not in a positive way. On hot summer days, the greenery on the roof has a cooling effect like natural air conditioning. “Black bitumen cardboard and gravel roofs can heat up to 80 degrees Celsius when it’s hot,” says Krzysztof Pompa, an expert at BHW-Bausparkasse, “on the other hand, the maximum temperatures for planted roofs are only around 20 to 25 degrees.”

With a view to the new district developments, which other city would be better suited than Berlin to take into account climate change, which is now undisputed, when drawing up urban land use plans? Unfortunately, no concrete urban ecological measures against the effects of climate change were written into the “Act to Promote Climate Protection in Development in Cities and Municipalities” in 2011. This omission should urgently be made up for with the help of this volume in order to come to urban redevelopment areas that improve living conditions in a comprehensive sense. “We have to establish green climate oases in the cities,” said Gerd Landsberg, Managing Director of the German Association of Towns and Municipalities, to the Handelsblatt. Kupka’s practical recommendations for action in the form of “green building blocks” for various types of greening would be a good start. If they are read and implemented .

According to a survey by the BHW Bausparkasse, 64 percent of homeowners would like more greenery in the neighborhood. Many still underestimate the enormous positive effects of green roofs and facades on the climate. Greening can lower the temperature around the house by up to five degrees and have a cooling effect on the urban climate in particular. However, according to the BHW survey, only very few of those surveyed know this (9 percent).