In a context marked by increasingly early and intense heat waves, mental health has become a central challenge in climate adaptation.
Heatwaves Undermine Psychological Well-Being
For several years now, scientific work has converged: extreme heat has direct effects on the mind. In a chapter titled “Mental Health and Climate Change” in its report “The Health Impacts of Climate Change on Populations: Understanding, Anticipating, and Acting,” IPCC – Pays de la Loire notes that the scientific literature now documents “an increase in anxiety levels and a deterioration in overall quality of life.” Researchers describe climate change as “amplifiers” of pre-existing vulnerabilities. Social, economic, or professional conditions can thus intensify the psychological effects of heat episodes. The authors of this report observe that when temperatures exceed seasonal norms, negative emotions rise within the population.
The studies cited in their report show that extreme heat is associated with greater psychological distress, a decline in positive emotions, increased fatigue, and an overall drop in well-being. Scientists also note a rise in depressive-toned language on social media and more self-reported mental health difficulties among people themselves.
These phenomena are not merely a temporary discomfort. According to the World Health Organization, heat places a significant burden on the body. The body struggles more to regulate its internal temperature, placing a heavy load on the cardiovascular system and the kidneys. WHO also notes that hot spells worsen several chronic conditions, including cardiovascular and respiratory diseases, as well as certain mental health disorders.
The health consequences of heatwaves are now well documented in France. Public Health France notes that around 15,000 additional deaths were recorded during the 2003 heatwave in just fifteen days. More recently, heat episodes caused nearly 2,816 excess deaths in 2022. While these data primarily concern the physical effects of heat, they illustrate the magnitude of the health stress caused by repeated heat waves.
Heatwave, Anxiety, and Mental Distress: Measurable Effects
The Pays de la Loire IPCC report also draws on recent regional data. Public Health France’s 2024 Health Barometer indicates that 79.8% of adults in the Loire region report having faced at least one extreme climate event in recent years. More than 60% say they have experienced at least two. Heatwaves are by far the most frequently mentioned events, ahead of droughts, storms, or wildfires.
This repeated exposure to climate events is not psychologically neutral. The survey shows that 10.9% of people who faced an extreme climate event in the past two years report psychological suffering. Women report greater mental health consequences than men. Researchers also observe that extreme climate events encourage the onset of post-traumatic stress symptoms, depression, or anxiety, regardless of age. Socially or economically vulnerable populations appear even more vulnerable.
The very anticipation of natural disasters affects morale. In the Pays de la Loire, 73.9% of residents think that an extreme climate event could occur in the near future, within the next two years. Among them, 67.8% associate this prospect with negative consequences for their physical or mental health. This rise in climate anxiety comes as heat waves become more frequent: France today experiences roughly four times as many heat waves as at the start of the 2000s.
Eco-Anxiety Rises with Heat and Climate Change
The heatwave also fuels a well-recognized phenomenon: eco-anxiety. The Pays de la Loire IPCC report defines it as “a psychological state of mental and emotional distress that an individual may feel in response to the threat of climate change.” A large international study of 10,000 young people aged 16 to 25 across ten countries, including France, already in 2021 showed that 59% described themselves as “extremely” or “very anxious” about climate change. More than 45% believed that this anxiety affected their daily life.
More recent work, however, nuances the idea of a phenomenon strictly generational. A 2025 survey conducted in France found that 75% of the population says they are little or not eco-anxious. Conversely, 10% of French people consider themselves highly eco-anxious and 15% moderately concerned. Women generally show higher anxiety levels than men.
In the Pays de la Loire, 5% of residents are strongly eco-anxious, a level close to the national average. Another study of 852 young people aged 18 to 30 in the region shows that 9% are strongly eco-anxious, while 25% are moderately so.
The proliferation of heat waves contributes to this concern. In its latest report, The Lancet Countdown on health and climate estimates that the global rise in temperatures now causes about 546,000 heat-related deaths each year between 2012 and 2021, a 23% increase from the 1990s.
High Temperatures, a Major Public Health Challenge
For specialists, the psychological distress associated with heat waves should not automatically be treated as a pathology. The regional IPCC report emphasizes a “continuum” idea: climate anxiety can stay moderate and sometimes even push people to engage more in collective or environmental action. However, the most severe forms can foster the development of anxiety or depressive disorders. The report’s authors therefore deem it necessary to improve screening and care for the most affected individuals.
French health authorities now stress the importance of prevention. Public Health France notes that heat waves can cause a very rapid deterioration in health, sometimes requiring urgent care. Public authorities recommend staying hydrated, keeping homes cool, and limiting physical exertion during peak heat periods.
The report also calls for avoiding overly alarmist rhetoric. Experts advocate for messages more focused on concrete solutions and societies’ adaptive capacities in the face of warming. Training health professionals in eco-anxiety and climate-related mental health also emerges as an increasingly important issue.
In a context where mental health has been designated a “Grande Cause Nationale” in France for 2025 and extended into 2026, the links between heat waves, extreme temperatures, and psychological balance are likely to occupy an increasingly prominent place in public policy.
