The initiative for the natural and gentle development of the Butterberg takes this as an opportunity to renew its demand to the city. The city should have the consequences of the Butterberg development for the microclimate in the center examined. According to the initiative, it has so far refused to do so, and there is also no political mandate.

"Our city center is apparently heating up faster and more strongly than the surrounding area and than other city centers throughout NRW," the initiative says. Exactly there, where in the past years living space had been created, senior citizen facilities have been built and for it green and open spaces had been sealed, with increasing expansion in the direction of Grüner Mitte and Butterberg-Areal.

The initiative refers, for example, to large-scale tree felling between Grantham-Allee and today's Technical Town Hall in 2007, and the grove between the university and the Rhein-Sieg-Gymnasium (RSG), which had to make way for the construction of the student houses in 2014. Or the old gravel pit between the RSG and the Children's Hospital, which is overgrown with trees and shrubs and was leveled in 2015 for the Ronald McDonald Oasis.

He said it was important to have experts investigate whether and how the heat island in the city center will change if the edge of the center towards the Grüne Mitte is built on. This is because further new structures are planned within the Butterberg development, including a parking garage up to seven stories high, office buildings and an experimental hall.

Building structures store heat, but can also block ground-level winds to equalize temperatures, the initiative said. That's why, during last year's citizen participation, they asked the city to examine whether and how a Butterberg development could negatively or perhaps positively affect the microclimate in the city center, they replied. "The city currently largely rejects this investigation with reference to large-scale studies for the Rhine Valley and the Victory Valley," the initiative said.

Instead, the city had referred to the planned planting of shrubs and trees and the creation of a water management concept with "water areas" that "will have a particularly high, cooling effect on the microclimate in the plan area." In more recent documents for the Butterberg development, which were submitted in the spring of 2022, however, only "infiltration swales" are planned instead of the water areas, according to the initiative.

To underline its demand, the Butterberg Initiative refers to a report of the German Meteorological Service, which addresses the investigation of the urban climatic changes of Bonn and also the city edges up to the Hangelarer Heide and the Butterberg.

The Intergovernmental Panel on Climate Change, the North Rhine-Westphalia Ministry of Construction and professional associations had also emphasized the need for microclimatic studies and climate change-compatible development in urban areas. In addition, the Federal Ministry of Construction has announced a funding program of 790 million euros for 2022 to make cities and neighborhoods climate-resilient and, in particular, heat-resilient.

The coalition agreement of the new black-green NRW state government also recognizes the great importance of fresh air corridors for city centers and sets them down as a binding goal, says initiative spokesman Andreas Fey. He and his fellow campaigners miss such a clear commitment from the city, but also from Sankt Augustin's politicians. (Original text: Nadine Quadt / Translation: Mareike Graepel)