Lower-income households in France are more exposed to ‘heat islands’

Lower-income households in France are disproportionately more affected by ‘heat island’ effects, when urban areas experience higher temperatures than surrounding rural areas, according to a new study by Insee.

‘Within cities, the heat island phenomenon affects neighbourhoods differently, depending on the density and quality of buildings, vegetation and levels of human activity,’ Insee noted.

Geographical differences

The French statistics agency noted that in cities like Paris, Bordeaux, Lille, and Nantes, both affluent and lower-income households experience heightened exposure to urban heat islands, as both groups are often concentrated in central, densely populated areas.

However, in other French cities, such as Lyon, Marseille, Montpellier, Nice, and Strasbourg, the pattern is reversed. Lower-income households tend to be more typically more exposed to the heat island effect in these cities, because they live in more densely populated, older urban districts, which lack sufficient greenery and have a higher concentration of buildings that trap heat.

At the same time, more affluent residents tend to live in newer, more suburban, and greener areas where heat accumulation is lower, reducing their exposure to high temperatures.

Keeping cool

In general terms, the study found that lower-income households, particularly those with young children or elderly members, are more vulnerable to heat waves due to several factors. These households are often less likely to have air conditioning, which can help mitigate the effects of extreme heat, and they are less likely to have access to a second home where they might escape high temperatures.

This vulnerability exacerbates the public health risks associated with extreme heat, as poor households with sensitive members are more at risk of heat-related illnesses.

The study, which was authored by Insee’s Julie Sixou alongside Céline Grislain-Letrémy (Banque de France, CREST-ENSAE) and Aurélie Sotura (Banque de France), underlines the importance of addressing urban planning and infrastructure issues to reduce temperature disparities and enhance resilience for vulnerable communities during extreme heat events. Read more here