The findings highlight the significance of heat-related deaths since 2014 and the need to strengthen adaptation measures in the context of rapid climate change. They also show that the impact of heat is not limited to heat waves alone but extends to periods of high temperatures throughout the summer. Santé publique France is therefore strengthening its prevention measures regarding behaviors to adopt during periods of high heat to protect the entire population.

Nearly 33,000 heat-related deaths between 2014 and 2022

The report published today highlights that heat waves are the extreme weather events associated with the highest human toll in metropolitan France. Beyond heat waves, high temperatures—which are often perceived as posing no health risk—also lead to significant risks. Santé publique France has developed an original method to estimate, at the departmental level, the annual mortality attributable to the general population’s exposure to heat, for all age groups and for people aged 75 and older.

The main findings for the summer periods of 2014–2022, across all metropolitan departments, show:

• Nearly 33,000 deaths are attributable to heat between June 1 and September 15 of each year, including 23,000 deaths among people aged 75 and older.

• Of these deaths, 28% occurred during heat waves as defined by the heat wave management plan, even though such periods accounted for only 6% of the days studied, thereby justifying particularly enhanced monitoring and prevention efforts.

The report thus highlights that the impact of heat is not limited to the most extreme periods. The population’s exposure to heat outside of heatwave periods, associated with a lower but more frequent risk, contributes more to the total impact than extreme heat associated with a higher but rarer risk. Between 1,000 and 7,000 deaths are attributable to heat each year, depending on weather conditions. These estimates of heat-related deaths complement heatwave assessments, which estimate excess deaths from all causes during heatwave periods (see box).

As expected, about two-thirds of the impact primarily affects people aged 75 and older, but it should be noted that a significant portion (one-third) affects people under the age of 75.

Santé publique France’s Heat Wave Alert and Monitoring System

Heat has a very rapid impact on the body. During periods of extreme heat, health can quickly deteriorate and require urgent care. Every year, between June 1 and September 15, Santé publique France activates the Heat Wave and Health Alert System (SACS) to anticipate heat waves likely to have a major health impact and enable the rapid implementation of prevention and management measures. Daily monitoring during heat waves focuses on the use of emergency care (visits to emergency rooms and SOS Médecins consultations), with a focus on the most specific indicators of heat exposure in summer (hyperthermia/heatstroke, dehydration, hyponatremia).

Taking Individual and Collective Action to Protect Ourselves from Extreme Heat

During periods of extreme heat, it is considered that the entire population must modify its behavior to protect itself. Overexposure (related to the environment or physical activity), the inability to avoid exposure (for practical or medical reasons), and individual susceptibility (age, health status, use of certain medications, etc.) are the main risk factors.

According to Météo-France, the heat waves of summer 2022 would have been “highly unlikely and significantly less intense without the impact of climate change.” Reducing the health impact of heat waves, which are becoming more frequent due to climate change, requires enhanced public health prevention efforts, prioritizing the most environmentally friendly and energy-efficient solutions, as well as fundamental interventions to make cities more resilient to heat.

On May 15, Santé publique France launched a new health promotion initiative aimed at instilling in the public health-promoting behaviors related to heat in daily life, not just during heat waves. Practical advice is thus provided to certain populations particularly exposed to heat (due to housing conditions or physical activity) to help them better adapt to recurring heat waves.

This initiative is supplemented during heat waves. As soon as an orange heat wave alert is issued in certain departments, Santé publique France mobilizes social media to disseminate messages tailored to the target population (adults, parents of children, and older adults). In the event of an orange or red heatwave alert covering most of the country, and upon instruction from the Ministry of Health and Prevention, the Authority for the Regulation of Audiovisual and Digital Communication (formerly the CSA) requires national TV and radio stations to broadcast all TV and radio spots produced by Santé publique France.

• Learn more: prevention tools

Today, in the face of increasing exposure to heat waves, it is necessary—in addition to prevention messages—to adopt a strengthened strategy for climate change mitigation and adaptation at the national and regional levels, with structural and systemic interventions to reduce the risk to human health throughout the summer.

In this regard, Santé publique France highlights several approaches to support municipalities in preventing the health impacts of heat waves on residents. These include protecting schoolchildren, the homeless, and vulnerable individuals (through municipal registries that identify elderly and/or disabled people for alert and protection purposes), as well as helping cities adapt to heat—notably through the concept of “nature in the city” (greening, heat-reflective surfaces, water fountains, water features)