Combining Social Aspects of Climate Change with Urban Heat Stress Modelling – a Case Study from Bremerhaven, Germany

The impacts of climate change create interconnected ecological, economic, and health challenges that act as multiple drivers shaping local social conditions in urban areas. While municipal adaptation strategies increasingly address physical risks such as heat, flooding, and drought, the social dimensions of climate change often remain underrepresented. Vulnerability to climate impacts, however, is not evenly distributed. Certain population groups – such as older people, children, people experiencing homelessness, and individuals with low income – are particularly at risk. Moreover, low-income neighborhoods are often disproportionately affected by heat waves. This is partly due to the fact that these areas typically have below- average access to open spaces such as parks or water bodies. Furthermore, the distance to public recreational areas often increases as household income decrease. Against this background, the paper presents a case study on heat stress modeling in Bremerhaven, Germany. The analysis focuses on the Goethestraße district, which faces significant socio-economic challenges and holds the lowest social index of the city. Bremerhaven itself is characterized by the second-highest unemployment rate and the highest rate of over-indebtedness among all German cities. The case study employs a top-down approach using scientific data – including environmental parameters, weather observations, and regional climate projections – as inputs for model simulations conducted with the “Tygron Platform”. This was complemented by a bottom-up approach involving key stakeholders from the city administration to integrate expert knowledge, local perspectives, and community-based assessments. Through this transdisciplinary and co-creative process, all major decisions – like the definition of the current and future climate scenarios to be taken into account, the potential adaptation measures to improve the thermal comfort (mainly the integration of green spaces, urban trees, and water areas), the integration of aditional stakeholders from the city admistration, the future communication of the modeling results – were taken collaboratively and on an equal footing. Beyond conventional urban climate modeling approaches and indices commonly applied in Germany, the study also incorporates planning principles from the Netherlands, notably the 3-30-300 rule. In addition to presenting modeling results, the paper discusses possible practical adaptation options and first next steps to strengthen socially inclusive climate adaptation strategies.