How do rising temperatures and more hot days affect cities, especially the heat stress on public squares? And what needs to be done in response to climate change? A team of Heidelberg University geographers led by Dr Kathrin Foshag investigated these questions using locations in the Heidelberg urban area. They collected local climate data and simulated various shading options using geoinformatics methods. They also surveyed users on their preferences and discussed design issues with local experts. To keep such public spaces usable in future, they need more greenery and variety, according to the interdisciplinary study. The results were published in the journal "Sustainable Cities and Society".
The researchers investigated heat stress and possible countermeasures on University Square in Heidelberg’s historic old town as well as the "Schwetzinger Terrasse" in Bahnstadt, the newly built passive house district. Meteorological parameters such as temperature, wind speed, and humidity were recorded in the summer of 2018 to analyse the baseline situation. The data showed especially the "Schwetzinger Terrasse" to be affected by very high temperatures. "The surface colour and the texture of these sites play an important role. Green areas do provide temperature regulation but only in their vital state," explains Dr Foshag, whose study is based on her doctoral thesis at Heidelberg School of Education and the Institute of Geography at Heidelberg University. Using methods from geoinformatics, the researchers also modelled the solar irradiation on the sites. They were able to simulate the effect of different shading options such as trees or solar sails on the small-scale climate on the public squares.
"When measuring during the summer months, we noticed that very few people lingered in either place. Using questionnaires and so-called mental maps, we asked passers-by and residents why," reports Dr Foshag. "It turned out that the desire to implement measures to adapt to the heat in the city is tied to the need for attractive and functional design, greenery and variety in public spaces." These findings enabled the researchers to develop solutions to improve the quality of these environments in cooperation with local experts, including the Heidelberg Office of Environmental Protection, Trade Supervision and Energy.
Dr Kathrin Foshag is currently working as a post-doctoral researcher at TdLab Geography, established by Dr Nicole Aeschbach at the Institute of Geography of Heidelberg University in 2018. Based on a transdisciplinary approach that combines methods from both the natural and social sciences, the work takes into account climate change issues in research, teaching and communication. Analyses, concepts, and solution approaches are developed in cooperation with experts working in the field.
K. Foshag, N. Aeschbach, B. Höfle, R. Winkler, A. Siegmund, W. Aeschbach: Viability of public spaces in cities under increasing heat: A transdisciplinary approach. In: Sustainable Cities and Society.