Climate Risk Assessment and Adaptation Options Assessment: Application of CLIMAAX toolbox for Genoa

Climate Risk Assessment (CRA) consists of four components based on the IPCC framework: (a) hazard, (b) exposure, (c) vulnerability, and (d) response/adaptation. Such assessment is essential not only to understand how each hydroclimatic hazard can have an impact on urban areas, but also to develop climate adaptation strategies. 

Although a wide range of  tools for  CRA have been developed, several challenges  limit their consistent application in the urban environment. First, a typical urban area can be exposed to multiple natural hazards, which requires a framework to assess multi-hazard multi-risk impacts. Furthermore, characteristics of hydroclimatic hazards (e.g., magnitude and spatio-temporal variations) can alter due to climate changes. Finally, future projections are scenario-based, which inevitably introduces uncertainty in CRA. 

In this context, CLIMAAX presents a comprehensive CRA toolbox including a series of practical workflows in terms of Python scripts, each focusing on a specific climate hazard. Together, the workflows enable consistent multi-hazard assessments. The hazards considered in the CLIMAAX toolbox include river and coastal flooding, heavy rainfall, urban heatwaves, relative and agriculture droughts, wildfire, heavy snowfall and blizzards, and windstorm. The toolbox is available for implementation to any European region, but it can be extended  to other regions with minor modifications to input data. To select climate projections, the CLIMAAX toolbox provides a workflow assessing bias and uncertainty of climate models/scenarios for any region in Europe. Using the CRA outputs, the toolbox supports key risk assessments that account for severity, urgency and capacity, enabling the integration of risk responses as the final step of CRA.

This study has a twofold aim. First, it attempts to showcase applications of three CLIMAAX workflows, including river flooding, heavy rainfall, and coastal flooding, to the city of Genoa, Italy. Genoa’s river networks have experienced multiple flood events, like the ones in November 2011 and October 2014. Furthermore, the city is also affected by intense rainfall, as shown by the heavy precipitation event in November 2025, which caused flash flooding and street inundation. Moreover, coastal flooding represents an additional hazard, with  the October 2018 event impacting beaches and coastal infrastructure. Based on the CRA results, river flooding was identified with the highest risk priority in Genova.  

Second, flooding hazard-specific risk outputs were translated into a spatially-explicit data-driven assessment of public-private adaptation infrastructure options at the city scale. Building on the CLIMAAX workflows, neighborhood-scale risk layers were mapped for pluvial flooding from heavy rainfall, fluvial flooding along Genoa’s river network, and coastal flooding to study adaptation options targeting different risk components. For a set of these options, alternative deployment strategies were explored, and avoided impacts alongside capital expenditures and operation and maintenance costs were quantified. This enables sub-city cost-benefit comparison of individual and combined infrastructures that best align with severity, urgency and capacity constraints, producing a basis for prioritizing adaptation pathways across Genoa’s neighborhoods.
Acknowledgement: This research work was carried out as part of the CLIMAAX project with funding received from the European Union’s Horizon Europe – the Framework Programme for Research and Innovation (2021-2027) under grant agreement No. 101093864.