Urban climate risk assessments (Hamburg, Germany)

Hamburg, a city with various climate-related risks, needs to adapt to climate change in a systematic, sustainable and cross-sectoral approach. At the organisational level, the interaction between administration and public companies is crucial for implementing adaptation strategies and consideration of the interactions between the various actors and sectors of the urban system, which is a prerequisite for sustainable adaptation planning. In addition, adaptation and mitigation must be weighed against each other to assess trade-offs and avoid incompatibilities (e.g., urban densification versus adaptation to climate-induced stressors), requiring tailored state-of-the-art climate and adaptation scenarios (e.g., Representative Concentration Pathways RCPs and Shared Socioeconomic Pathways SSPs).

Adaptation at the city scale requires very fine-scaled (high-resolution) data. Granulated data on exposure and vulnerability of urban sectors, infrastructure and population as well as data on climate-induced stressors is managed by different city authorities under the Hamburg City Senate, and not always publicly available. Understanding climate risks and barriers to adaptation at urban scale requires a concerted effort across city authorities for data curation and sharing. Data related to climate-induced stressors are often not updated or do not utilise European or global data portals (e.g. Copernicus). So far 572 datasets (e.g., on green spaces, city trees, population data, infrastructure data, building characteristics, soil properties, noise levels, air pollution, weather station data) from different sources or authorities is gathered in a data portal (Geoportal Hamburg), containing metadata and maps in pdf format. Hamburg’s adaptation portals are referenced in Climate-ADAPT but only in terms of qualitative information.