Heat wave vulnerability varies greatly within cities, study finds

A research group at the University of the Basque Country (EHU) has assessed how vulnerable different parts of cities are to heat waves. The group reported that vulnerability varies greatly from one area to another within a city. The work was published in the journal Cities and carried out by the SAREN (Sustainable And Resilient built ENvironment) group, led by Leire Garmendia. The group applied its method in Bilbao, Madrid and Cáceres, three cities in different climate zones.

Researcher Irantzu Álvarez said the risk posed by heat waves is not measured solely by temperature and has multiple dimensions. According to the group, the assessment takes into account how the city is built, including buildings and public spaces; which areas are hardest hit by high temperatures; and how many people are affected and how vulnerable they are. Researcher Laura Quesada said the team measured the vulnerability of each building and open space in the three cities.

The methodology produces urban vulnerability maps that show where priority action should be taken to tackle heat waves, the group said. The group stated that adaptation measures can be implemented much more effectively with this type of study. Applying the method in the three cities showed it is fully replicable and can be used anywhere, which the group said makes it more robust and a useful tool for municipalities.

In all three cities, the study highlighted the importance of socioeconomic variables when measuring vulnerability, according to the research group. The group stated that people with low incomes and older people are far more vulnerable. It also said a building may be sensitive to heat while its residents have the financial means to protect their home from it.

The group said vulnerability is not the same throughout a city, so it is not enough to say that one city is more vulnerable than another. It said there are different hot spots within a city, and there may also be different situations within the same neighborhood, which is why this type of detailed research is necessary. The research used socioeconomic variables, building characteristics and environmental variables drawn from a variety of sources.