Urban Climate Risk Archetypes: A Multi-Hazard Assessment of European Waterfronts

Coastal waterfronts are among the most dynamic and vulnerable parts of the urban fabric, concentrating population, economic activity, critical infrastructure and cultural heritage at the land-sea interface. These areas are increasingly exposed to interacting climate hazards and cascading impacts, demanding a shift from single-hazard assessments to a multi-risk perspective consistent with recent IPCC guidance. Here we present a methodology to identify and compare “Urban Climate Risk Archetypes” across the waterfronts of 31 major European coastal cities, providing an evidence base to support risk-informed adaptation planning.

We discretize the coastal urban zone using a 25×25 m grid within a 300 m coastal buffer to capture fine-scale spatial heterogeneity. Risk is assessed through a compound framework that integrates hazard intensity, exposure, and vulnerability across seven interrelated hazards: coastal flooding, heatwaves, wildfires, drought, extreme precipitation, sea-surface temperature anomalies, and extreme winds. This approach explicitly takes into account the interactions of climate hazards and compound events within risk. Exposure is quantified using economic, physical, demographic, and territorial indicators, while vulnerability is represented through human, infrastructural, and ecosystem fragility profiles, incorporating variables such as age structure, access to health services and income-related sensitivity.

To handle high-dimensional, multi-hazard information and enable cross-city comparability, we apply a hybrid unsupervised learning workflow to derive recurrent risk patterns within 14 land-use groups. The resulting clusters define “risk archetypes” that transcend geography, revealing how comparable waterfront configurations (e.g., industrial port areas versus residential areas or existing marinas) can exhibit similar multi-risk signatures across different European regions. Archetypes are evaluated for present conditions using historical data and for future climates using projections for 2050-2070 and 2080-2100 under SSP2-4.5 and SSP5-8.5.

The archetype framework supports decision-making by (i) highlighting hotspots where multiple hazards co-locate with high exposure and vulnerability, (ii) enabling transfer of adaptation lessons between cities with similar risk profiles, and (iii) clarifying synergies and trade-offs among measures across land-use contexts. Overall, the approach offers a scalable pathway from multi-risk diagnosis to targeted adaptation strategies that strengthen urban waterfront resilience under compound and cascading extremes.