Urban Geo-climate Footprint (UGF) for Classifying Italian Cities by Geological and Climatic Features

Urban areas are increasingly exposed to complex interactions of geological, climatic, and anthropogenic pressures. The UGF methodology (Lentini et al., 2024), already applied to more than 40 European cities, provides a structured approach to assess these multi-dimensional conditions and support urban planning and risk management. In this study, UGF was applied to 21 Italian regional capitals, selected to capture the geographic, climatic, and structural diversity of the country, from alpine regions to coastal plains and southern volcanic districts. Italy thus represents an ideal natural laboratory to test the methodology, offering a wide range of geological and climatic settings within a single country.

The methodology integrates multiple drivers: deep geological processes (DEE, e.g., seismicity and volcanism, gas emissions), superficial processes (SUP, e.g., landslides, subsidence, floods, coastal erosion), exogenous processes (EXO, e.g. heavy rains, droughts, sea level change), geological complexity (GEO, e.g., stratigraphy, groundwater, slope), and anthropogenic pressures (SAP, e.g., land use change, soil sealing, pollution). For each city, the UGF Index quantifies the intensity of these drivers, allowing classification into four UGF classes that reflect the spectrum of urban geo-climatic conditions.

Results from Italy highlight a wide range of situations: Trento and Campobasso fall into UGF-1, indicating minimal geologic-climatic pressures, while Napoli and Genova are classified as UGF-4 due to the combined influence of high-intensity drivers, including active volcanism, high seismicity, subsidence, and strong anthropogenic pressures. Intermediate classes (UGF-2 and UGF-3) include cities such as Milano, Firenze, Bari, and Venezia, where moderate interactions of these drivers prevail.

Geographical patterns emerge from the analysis of drivers. UGF index generally increases southward, reflecting higher exposure to Mediterranean climatic extremes, active seismicity along the Apennines, and southern volcanic districts. Coastal cities show high SUP and EXO contributions due to erosion, storm surges, and sea-level rise, while SAP is prominent in large urban centers, reflecting land consumption, groundwater contamination, and subsurface instability. The GEO driver is relatively consistent across the country, emphasizing Italy’s intrinsic geodiversity.

It is important to note that UGF classes do not rank cities by “risk” or “misfortune,” but rather identify the prevailing geological, climatic, and anthropogenic pressures to support planning and mitigation. A semi-qualitative assessment of geo-benefits further highlights positive contributions to urban systems, with cities such as Milano, Napoli, Palermo, Roma, Trento, Trieste, and Venezia showing higher scores.

Overall, the UGF approach provides an explicit and concise understanding of urban geo-climatic conditions, also integrating natural hazards, climatic pressures, and human impacts. It highlights local differences often masked by traditional indicators and offers a valuable tool for evidence-based urban planning, climate adaptation, risk reduction, and sustainable urban regeneration. The methodology emphasizes the recognition of the subsurface as a primary urban infrastructure, essential for resilient city development.

 

Lentini, A., Galve, J. P., Benjumea, B., Bricker, S., Devleeschouwer, X., Guarino, P. M., Kearsey, T., Leoni, G., Puzzilli, L. M., Romeo, S., Venvik, G., & La Vigna, F. (2024). The Urban Geo-climate Footprint approach: Enhancing urban resilience through improved geological conceptualisation. Cities, 145, 105287. https://doi.org/10.1016/j.cities.2024.105287