Climate change promises us heatwaves and has already shown the vulnerability of the elderly. But exposure to high temperatures can also affect other segments of the population who risk seeing their health deteriorate. Others will be able to withstand the effects of global warming. What are the factors involved in these inequalities between individuals?
The heatwaves of the summer of 2022 marked the spirits of the French, with a month of July that was the hottest ever measured on a global scale. With an increase in deaths and temperatures of 16.7%. have reached more than 42°C In this period it is essential to identify the most vulnerable people to cope with climate change and the increase in the intensity and frequency of this phenomenon. In this context and in the light of the latest report of the IPCC which warns of the acceleration of climate change, one can wonder about the factors of vulnerability faced by some groups of the population.
Some are quite obvious, such as age or location: this plays an important role in regions most exposed to extreme heatwaves – such as Auvergne-Rhône-Alpes exposed to more than 20 abnormally hot days per year during June, July and August in recent years. These are the factors that are said to be tangible, that can be measured or quantified.
But other factors, more surprising and more intangible, like mental healthare also highlighted by the economic literature.
Age, inadequate housing… tangible factors
Unsurprisingly, age plays a large role in this vulnerability: the elderly are obviously most at risk in the event of a heat wave.
Thus, during the scorching summer of 2022, deaths increased by 20%. 20.2% in people over 75 due to their fragility linked to chronic diseases.
People who say they suffer from the summer heat often live in poorly insulated and difficult to ventilate houses, with maximum summer temperatures in homes exceeding 30°C – they are also victims of overcrowding.
The concept of thermal comfort takes on its full meaning. The quality of housing and the presence of comfort equipment that allows it to adapt to heat waves, such as air conditioning systems, will influence the degree of vulnerability of its occupants. Survey data conducted by us reveal that only 22.7% of households have an air conditioning system (mobile or fixed) in 2020, while 7 out of 10 people will be exposed to intense heat every year.
Adjustment, mental health… intangible factors
As regards intangible factors, whose relationship with heat waves appears less evident, the economic and psychological literature is increasingly focusing on the link between cognitive abilities and adaptation to extreme events. An individual’s cognitive abilities will influence his decision-making and reflection process, but also his perception of certain situations and his ability to adopt appropriate behaviors.
More specifically, it has been found that the state of depression exerts a negative effect on the likelihood of reacting with appropriate behaviors in the face of extreme heat waves. A fact that can be explained by reduced executive or memory faculties but also by a decision-making process strongly guided by emotions. By generating a feeling of pessimism, helplessness and doom about their lives and their future, people in a state of depression will limit their adaptation to heat waves and thus increase their vulnerability.
This point is all the more important as the cognitive abilities of individuals decrease with age and this currently occurs in almost one in five people have suffered or will suffer from depression in their lifetime.
Furthermore, in this context in which adaptation will be a tool to address one’s own vulnerability, the question of the accentuation of inequalities arises. Whether it’s through the thermal renovation of one’s home, the purchase of an air conditioning system or the increase in the energy bill to cool off, the gap with the more modest families will widen.
The cost of this adaptation will not be affordable for all families and will leave some families in critical situations where they will be highly exposed to the health consequences of heatwaves. So there are discrepancies between income quintiles and household equipment rates to cope with climate change. The observation is clear: wealthier households will be better able to cope with extreme heat waves.
Unfortunately, economic inequalities are not the only ones that could be exacerbated. Problems in accessing care can also be a source of inequalities in the face of heatwaves. Physically and mentally ill people living in medical deserts and exposed to heatwaves risk seeing their health deteriorate.
It will therefore be more than necessary to find durable solutions over the next decade to overcome these vulnerability factors, ensuring thermal comfort while ensuring that inequalities do not widen.