Vulnerability Assessment of Historic Areas to Heat Waves. The Case Study of Bilbao

The impacts of climate change, such as extreme events and progres-sive global warming, threaten the conservation and habitability of urban cultural heritage. Understanding climate risks to heritage must be part of planning and policy decision-making processes to increase the resilience and sustainability of both social and built environmental systems.. However, despite a large body of literature on climate-related hazards, there is a notable knowledge gap regarding a holistic conceptualization of hazards in historic urban areas, especially in the case of heat waves and urban heat island phenomena. The main goal of this study was to analyze and represent the interaction between historic built environment and heat waves via Geographic Information Systems (GIS) data, considering the vulnerability of historic areas both as urban systems and as heritage areas. To frame a holistic approach, socio-economic, cul-tural, governance (services and resources) and physical (gathering tangible characteristics of all infrastructures, elements and buildings) aspects of the system are taken into ac-count. To this end, a multicriteria risk assessment methodology is developed. Key performance indicators, criteria and requirements addressing relevant vulnerable elements of historic urban areas are identified for the development of the methodology. Moreover, as the foundation for the risk assessment, a categorization based on vulnerability to heat waves is proposed for both buildings and urban spaces. Here, this methodology’s results and its application on a GIS-based model in the historic area of Bilbao (Basque Country, Spain) are presented. This work aims to be replicable and to serve as a reference for future holistic assessments of heatwaves risks in historic urban areas worldwide.