Unequal exposure to heatwaves in French cities in a changing climate

Urban areas are commonly hotter than rural counterparts. Heat exposure leads to health risks, including excess mortality. Research suggests that marginalized groups are more exposed than the general population to environmental hazards. Inequalities of exposure to urban heat island putting higher heat stress on persons of color and people living below the poverty line have been shown for an ensemble of U.S. Cities (Hsu et al., 2021). Less is known about these inequalities of exposure in Europe. The influence of projected climate change on these inequalities is also unclear. In this study, we investigate inequalities of exposure across different types of population for 10 major French cities.

 

We combine surface temperature data with demographic data to answer these questions. The meteorological data (days with a high heat stress and number of heatwaves days) is extracted from the Urbclim model (De Ridder et al., 2015), at 100-meter resolution, with an emission scenario following the current policies. The demographic data consists of a census-derived ensemble of 28 variables at 200-meter resolution, including age classes, age of buildings, density, income level and types of households. We find that neighborhoods with households with lower income and a higher density of children below the age of 10 have a higher exposition to heatwaves than the rest of the population. The exposure to heatwaves grows for all groups with higher levels of global warming but the inequalities of exposure still remain.

 

 

Bibliography:

De Ridder, Koen, Dirk Lauwaet, and Bino Maiheu. "UrbClim–A fast urban boundary layer climate model." Urban Climate 12 (2015): 21-48.

Hsu, A., Sheriff, G., Chakraborty, T. et al. Disproportionate exposure to urban heat island intensity across major US cities. Nat Commun 12, 2721 (2021). https://doi.org/10.1038/s41467-021-22799-5