M. Sc. Jasmin Uttner
Heat risk in German cities: Vulnerability and exposure of the urban population
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Background and research gap
Cities heat up more than their surrounding areas (urban heat island effect). This problem is exacerbated further by climate change, which results in more frequent and intense heatwaves. As a result, urban populations are particularly affected by heat, which can lead to serious health issues and even death.
However, city residents are affected by heat in different ways. Firstly, heat is distributed unevenly within urban areas, meaning that people are exposed to varying degrees of heat (exposure). Secondly, certain population groups, such as the elderly, young children and people with pre-existing medical conditions, are more sensitive to heat than others (sensitivity). Thirdly, people have varying abilities to protect themselves from heat or cope with its effects in daily life (adaptive capacity). These three dimensions are key components of the risk framework developed by the Intergovernmental Panel on Climate Change (IPCC, 2019).
In order to effectively reduce heat-related health risks with limited municipal resources, targeted climate adaptation measures are necessary. This requires detailed information on exposure, vulnerability, and adaptive capacity in order to identify the population groups most at risk. However, previous studies have mostly examined only individual aspects of heat risk, and there is a need for more comprehensive research. While the spatial distribution of heat in many German cities has already been well researched, studies on sensitive population groups often rely on statistical data. In contrast, the population’s adaptive capacity has been considered less frequently to date. Furthermore, there is a lack of insight into how heat stress varies across neighborhoods and population groups. The experiences of those affected and the knowledge of local stakeholders have also only been taken into account to a limited extent so far. Therefore, research approaches that consider all three risk dimensions together, combining quantitative data with subjective experiences of heat and local knowledge, are needed.
Research objective and research questions
The aim of the study is to identify population groups that are particularly affected by heat at a sub-city level. In this context, the study applies the IPCC risk framework and its three dimensions (exposure, sensitivity, and adaptive capacity). The findings will be used to derive targeted recommendations for climate adaptation.
The following research questions are therefore addressed:
- Which population groups are particularly affected by heat, and why?
- In which everyday situations is heat stress particularly high?
- What differences in heat stress arise at the neighborhood level?
Research method
To answer the research questions, a mixed-methods approach combining quantitative and qualitative research methods is being used.
First, a systematic literature review is conducted to establish the theoretical basis for the subsequent empirical analysis. This provides valuable insights into the factors that influence the three dimensions of heat risk, which are essential for designing the household survey. The quantitative online survey will be conducted in neighborhoods particularly affected by heat stress in the two case study cities, Dresden and Frankfurt am Main. As well as assessing exposure and sensitivity, the survey focuses on the subjective perception of heat stress in various everyday situations and the individual coping strategies of city residents. Secondary data, such as climate function maps, municipal statistics, and the results of other research projects, will also be incorporated. Furthermore, interviews with experts and local stakeholders will provide important, location-specific background information to help answer the research questions.
