Climate change is the greatest global health threat facing the world in the 21st century. Climate change profoundly impacts public health and well being through, for example, extreme weather and climate events, the spread of infectious diseases, and ecosystem degradation. In the next decades, substantial increases in morbidity and mortality are expected in association with a range of health outcomes, including heat-related illnesses, illnesses caused by poor air quality, under-nutrition from reduced food quality and security (1).

The model of climatic risk developed by the Intergovernmental Panel on Climate Change (IPCC) (2) is particularly adapted for public health. It presents the emergence of risk from interactions between specific types of climatic hazards, the exposure and vulnerability to those hazards, and the responses taken within the health sector and by communities (3).

Climate change will impact human health and well-being in a variety of direct and indirect ways that depend on exposure to extreme (e.g., floods) and chronic (e.g., changing climate normals) hazards.

These hazards can be associated with direct (e.g., daily temperature rising), indirect (e.g., migration) or vicarious (e.g., media depictions of climate change) exposure(s). For example, every 1^°C rise in temperature increases the incidence of age-adjusted diabetes by 0.314 per 1000 (4).

Finally, individual and collective characteristics over-expose people to climate hazards. These vulnerabilities increase the risks of climate-sensitive disorders, injuries, morbidity, or deaths. The 2022 IPCC report identified people with cardiovascular and respiratory diseases, cancer, diabetes and poor mental health among the most vulnerable subgroup to chronic and extreme climate hazards.

Thus, limiting the dramatic consequences of climate change for public health means (see Figure): identifying and modifying adaptation strategies that reduce exposure, identifying the most vulnerable groups of people to improve individual and collective resilience, and promoting strategies with benefits in terms of greenhouse gas reductions and health prevention.

• 1. Haines A, Ebi K. The Imperative for Climate Action to Protect Health. Solomon CG, éditeur. N Engl J Med. 17 janv 2019;380(3):263‑73.
• 2. Corvalan C, Villalobos Prats E, Sena A, Campbell-Lendrum D, Karliner J, Risso A, et al. Towards Climate Resilient and Environmentally Sustainable Health Care Facilities. Int J Environ Res Public Health. janv 2020;17(23):8849.
• 3. Intergovernmental Panel On Climate Change (Ipcc). Chapter 7: Health, Wellbeing and the Changing Structure of Communities. In: Climate Change 2022 – Impacts, Adaptation and Vulnerability: Working Group II Contribution to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. 1^re éd. Cambridge University Press; 2023
  
• 4. Al-Shihabi F, Moore A, Chowdhury TA. Diabetes and climate change. Diabet Med. 2023;40(3):e14971.

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