Cologne city center: White flags for shade and cooling off!

Cologne city center: White flags for shade and cooling off!

Since today, white flags have been flying over Hohe Strasse in downtown Cologne, which are not only eye-catching but also have a practical use. These flags are intended to provide welcome cooling in the summer heat by casting shadows. The project called “Cologne City Center Climate Laboratory” is significantly supported by the University of Cologne and the Aachener Grund Vermögens. In addition, scientific support from students studying geography and meteorology is taking care of the evaluation of this campaign, which is being carried out for the first time as continuous, high-resolution measurements in a pedestrian zone in a large German city.

The campaign was initiated by Cologne City Marketing and has the advantage that temperature developments in areas with and without flags are systematically recorded. For this purpose, special measuring stations were installed, the data from which could form the basis for future measures in other shopping streets. The flag campaign is financed by the city of Cologne and federal funds. This shows the importance of finding creative solutions to rising temperatures and the challenge of climate change. As ksta.de reports, the initiative is accompanied by intensive scientific analyzes to confirm its effectiveness.

Heat loads in the city

The question of urban heat pollution is not new. Studies by the German Weather Service show that the number of hot days in Cologne could increase dramatically by the middle of the century. According to the urban climate model Muklimo_3, an increase in hot days of up to 150 percent can be expected when comparing the years 1971 to 2000 with the forecasts for 2021 to 2050. This means that temperatures can rise above 40 degrees Celsius on summer days. The need for effective cooling measures is constantly growing, which makes projects like the climate laboratory particularly relevant. An analysis shows that the dominant warming is exacerbated by urban structures.

But how does this intensive urbanization and the resulting high temperatures come about? The urban heat island effect (UHI) contributes significantly to the temperature differences between urban and rural areas. Wherever density of urban structures accumulates, temperatures see an increase of 3°C to 12°C, depending on geographical location. This not only has an impact on the well-being of citizens, but also on general climate conditions, as stadt-koeln.de notes.

Global warming in focus

In addition to local effects, researchers worldwide note that urban areas make up only 4% of the global land area, yet most weather stations are located there. This influences the picture of climate change, as temperatures in cities are shown to be higher and higher due to urbanization factors. A recent study suggests that urban heat islands could explain up to 40% of the temperature increase since 1850. Critics warn that this bias influences our perception of climate change and the actions needed.

In summary, the initiative in downtown Cologne not only presents an innovative solution to summer heat, but also stands in a larger context in which the fight against global warming and urban heat islands play a central role. Here it becomes clear how locally conceived projects can meet global challenges. The findings from the campaign could soon be well received in other cities.

For further details, we encourage our readers to follow the comprehensive reports on eike-klima-energie.eu and the latest analyzes on urban climate footprints on stadt-koeln.de. The future of Cologne city center depends on the decisions we make today.