In order to determine that Frankfurt must adapt to climate change, Rosemarie Heilig (The Greens), head of the environmental department, first looks at the extreme weather in Spain and Italy with heat and drought as early as spring and subsequent flash floods. But also on your own doorstep: In 2018, Frankfurt was the warmest city in Germany throughout the year. In July 2019, the highest temperature to date was measured at 40.1 degrees. "Circulatory diseases increase in such heat waves, especially small children and the elderly suffer," said Heilig on Tuesday in the shadow of the Senckenberg Research Institute and Natural History Museum, whose courtyard has been planted with shrubs and trees for several years. A role model for Heilig.

Bernhard Biener

Editor at the Rhein-Main-Zeitung

  • Follow I follow

Since 10 May, an open space statute has been in force in Frankfurt, the declared task of which is "climate adaptation". Among the most important points is the ban on so-called gravel gardens and the obligation to green facades and flat roofs. This sounds plausible at first: "An overgrown wall is eleven degrees cooler than a bare one," says the head of the environmental department. Not all regulations are new at their core. The Hessian building code also provides for areas to be greened, said the designated head of the planning department, Marcus Gwechenberger. Gravel gardens are therefore not really allowed so far. However, the statutes set out the rules more concretely.

Hopes and fears

"We apply the same standards to inner development as we do to new neighborhoods," said Gwechenberger. He cited Bockenheim, Nordend and Sachsenhausen as examples. The climate function map of Frankfurt shows that the densely built-up districts of the city centre have the greatest "overheating potential".

An understandable goal is one thing, mediation is another, as the Greens are currently experiencing on the subject of heat pumps. A brochure that has now been presented is intended to provide information on the matter of open space statutes, which can be accessed at the Internet address www.bauaufsicht-frankfurt.de and is also handed out to the builders in printed form during construction consultations.

On 75 pages in large format, it explains in detail what is meant by the individual paragraphs. It could be that some of the hopes of the proponents are put into perspective as well as some of the fears of the opponents. The one with the three meters, for example: That's how high facades have to be greened, but only to 50 percent and minus the window areas. This means that in many cases you don't even need a ladder for maintenance, because the greenery only has to reach 1.50 meters high over the entire wall. Not to forget that instead of 20 square meters of exterior wall greening, a medium and large-crowned deciduous tree suitable for the location can also be planted. In some places, this sounds a bit like the "bureaucratic monster" that the open space statute is not supposed to be, according to Gwechenberger.

Assumption of half of the costs

He relies on the simple formula: "Bushes and trees bring the most." In the search for a real-life solution, the construction consultation should help. "At the same time, we also want to make greening palatable to private individuals," said Simone Zapke, head of the building supervision. The statutes only have to be applied in the case of a conversion or new construction. "If you renovate the roof, you don't have to plant the whole property." For the new roof, however, the greening obligation already applies, if the angle of inclination is not too large.

What remains are the complaints of the homeowners' association and the Chamber of Industry and Commerce about the increase in the cost of construction. Heilig pointed out that half of the costs up to an amount of 50,000 euros would be covered by the "Frankfurt refreshes" program. "A tree on an area of 200 square meters does not make a project uneconomical," Gwechenberger added. Zapke, on the other hand, cited the required parking spaces as a real cost factor. Here, in turn, the city has created a relief option with the innovation clause. In Frankfurt, for example, a car-sharing agreement or the provision of cargo bikes can replace a certain number of parking spaces.

Senckenberg Director Andreas Mulch promoted creativity in order to meet the demands of people and nature. Science can say what is good. It is up to politicians to define the boundary conditions.