The SAREN group at the University of the Basque Country (EHU) has rolled out a methodology to measure the vulnerability of buildings and open public spaces to heatwaves

The methodology, applied in Bilbao, Madrid and Cáceres, has shown that socio-economic conditions and the characteristics of the urban fabric have a significant influence on vulnerability. The tool generates vulnerability maps that help determine where adaptation measures to combat heatwaves should be prioritised.

Extreme weather events are getting increasingly more frequent and severe as a result of climate change. Heatwaves are a prime example, as they have direct effects on health, thermal comfort and the liveability of cities, which is why it is vital to conduct climate risk assessments to guide cities’ adaptation policies and prioritise action in the most vulnerable areas.

The SAREN (Sustainable And Resilient built ENvironment) research group at the University of the Basque Country (EHU), led by Leire Garmendia, is assessing the effectiveness of adaptation solutions that can be used to minimise the impact of heatwaves on buildings and outdoor spaces in cities. The research is being carried out as part of the OLADAPT project, funded by Spain’s Ministry of Science, Innovation and Universities, in collaboration with the Polytechnic University of Madrid, the University of Extremadura and the UNESCO Chair in Sustainable Development and Environmental Education at the EHU, in line with the guidelines of the Intergovernmental Panel on Climate Change (IPCC).

“We are looking at how to conduct a multi-dimensional and multi-scale assessment of the risk posed by heatwaves in urban areas. The risk posed by heatwaves is not measured solely by temperature; it has multiple dimensions,” explains the group’s researcher, Irantzu Álvarez. Implementing more appropriate policies involves taking into account, firstly, how the city is built (both buildings and public spaces); secondly, the areas of the city hardest hit by high temperatures; and finally, the number of people affected by this situation and the degree of vulnerability or lack of protection of the people living there. “In this study, we have measured the vulnerability of each of the city’s buildings and open spaces in Bilbao, Madrid and Cáceres (all three located in different climate zones),” adds researcher Laura Quesada.

The methodology developed by the EHU’s SAREN research group makes it possible to produce urban vulnerability maps that clearly show where priority action should be taken to tackle heatwaves: “Adaptation measures can be implemented much more effectively with this type of study,” they say. Furthermore, applying the methodology in these three cities has shown that “the methodology is fully replicable; it can be used anywhere. This makes the methodology more robust. It is a genuinely useful tool for municipalities and cities.”

Buildings in lower socioeconomic areas are more vulnerable

In all three cities, the study has highlighted “the importance of socioeconomic variables when measuring vulnerability. People on low incomes, older people, etc. are far re vulnerable,” the research group states. Vulnerability is not the same throughout a city. It is therefore not enough to say that one city is more vulnerable than another, because there are different hotspots within the city. There may also be different situations within the same neighbourhood, which is why this type of detailed research is necessary.”

The research used a large amount of data drawn from a variety of sources. Socioeconomic variables, building characteristics and environmental variables were all taken into account. For example, “a building may be sensitive to heat, but its residents may have the financial means to protect their home from it,” they explain. Álvarez and Quesada explain that the fact that the unit of analysis is the building is what allows adaptation measures to be better targeted: “This methodology shows which buildings or types of buildings should be renovated or adapted first.” Furthermore, the impact of the surrounding environment on the building has also been measured, which has made it possible to link the building’s vulnerability to that of open public spaces: “Buildings may be highly vulnerable but have plenty of green areas and shade around them. Taking all of this into account means that adaptation measures can be implemented in different ways.”

Additional information

Laura Quesada is an architect specialising in the restoration and conservation of historic heritage, and works at the Vitoria-Gasteiz School of Engineering. Irantzu Álvarez is a Technical Engineer in Surveying and holds a degree in Geography, and works at the Bilbao School of Engineering. Both are lecturers on the Master’s Degree in Construction Engineering at the Bilbao School of Engineering.

Bibliographic reference

Laura Quesada-Ganuza, Irantzu Álvarez González, Ane Villaverde García, Leire Garmendia Arrieta

Assessing urban heatwave vulnerability through a multiscale and multicriteria GIS-based approach: Evidence from three Spanish cities

Cities

DOI: 10.1016/j.cities.2026.107514