Equity

The level of risk associated with climate change in a given area is the product of three parameters: local climate hazards, the exposure of a population to these hazards, and the vulnerability of the exposed population. At all scales, these three parameters are characterized by high variability. In terms of hazards, for example, the temperature anomaly in 2024 was +2.92°C in Europe compared to +1.60°C globally (relative to the period 1850-1900), while the center of Paris recorded temperatures up to +8°C on summer evenings compared to the Bois de Vincennes (July 25, 2019). Exposure is also highly variable, ranging from unoccupied areas to cities with more than 20,000 inhabitants per square kilometer. In terms of population vulnerability, the level of aging of residents, quality of housing, and access to vegetation can vary greatly from one country to another and from one neighborhood to another. Climate action must be planned with the criticality level of these three parameters as input data.

Focusing on France, the situation is the same, with sometimes very high levels of risk and/or sensitivity in certain neighborhoods, from northeast Paris to the Mediterranean coast and Mayotte. Seventy percent of residents in the city's priority neighborhoods report suffering from excessively high temperatures in their homes in summer, compared to an average of 56%. Beyond the intrinsic quality of the buildings, this type of area often suffers from aggravating environmental factors such as air pollution, noise, and a lack of green spaces, which limit the ability to cope with extreme weather events (inability to open windows at night or cool off in a park).

Of course, each part of the city must be adapted according to development and redevelopment opportunities. Nevertheless, given financial and time constraints, it seems necessary to prioritize action to target particularly vulnerable areas and thus correct their sensitivity in order to offer decent living conditions to the entire population. Renovation projects in precarious and degraded urban areas must therefore embrace adaptation, whether in public or private spaces, indoors or outdoors, to avoid situations of vulnerability to extreme weather events, as was and still is the case with energy prices in relation to the thermal renovation of buildings. Although less visible than those affecting heritage or tourist sites, these adaptation projects must be placed at the top of the list in order to contribute to a certain degree of climate equity.