Global warming: a major threat to human health

---

Extract from the article: From sweltering heatwaves to devastating floods and the insidious proliferation of infectious diseases, climate disruption poses a complex and growing threat to humanity. The World Health Organization (WHO) sounded the alarm at the UN climate...

---

From sweltering heatwaves to devastating floods and the insidious proliferation of infectious diseases, climate disruption poses a complex and growing threat to humanity. The World Health Organization (WHO) sounded the alarm at the UN climate conference in late 2024, calling climate change the greatest threat to human life.

This environmental crisis acts like a silent epidemic, undermining not only the direct environment, but also the functioning of vital organs and the ability of healthcare systems to protect effectively. From the quality of the air we breathe, to the safety of the food we eat, to the emergence of new disease vectors, the climate's impact on health is profound, multi-faceted, and demands urgent, concerted action.

Health consequences

The health repercussions of climate change can be divided into two main categories : firstly, direct consequences linked to extreme events, and secondly, indirect consequences resulting from a cascade of chain reactions. The direct consequences are mainly manifested through the intensification of heat waves and the multiplication of extreme climatic events. Heatwaves, for example, lead to an increase in hyperthermia, dehydration, kidney disorders, strokes, as well as cardiovascular and respiratory complications, which can lead to fatal organ failure. A study published in “The Lancet” in October 2024 reveals that in 2023, the global population was exposed to an average of 50 additional days of intense heat, resulting in significant excess mortality, particularly among people over 65.

At the same time, the intensification of storms, floods and droughts is causing drowning, heart attacks, injuries and significant psychosocial consequences. Valérie Masson-Delmotte, climatologist at the French Atomic Energy and Alternative Energies Commission (CEA) and expert on the Intergovernmental Panel on Climate Change (IPCC), highlights the profound impact of these phenomena on psychological health, ranging from the trauma of population displacement to growing anxiety about the degradation of the planet, a phenomenon now known as eco-anxiety. Indirect impacts are a complex set of reactions. The resurgence of infectious diseases is a worrying example.

Climate change creates favorable conditions for the proliferation and geographic expansion of disease vectors such as mosquitoes, responsible for the transmission of dengue fever, chikungunya and malaria. The climate now affects all regions, making them more vulnerable to climate change. "The seasonal duration of mosquito-borne diseases will increase. Diseases such as dengue fever and chikunguny will become major concerns in northern countries," explains epidemiologist Arnaud Fontanet, in November 2024 at the Institut Pasteur. The risk of dengue transmission has increased by 46% over the last decade, with 5 million cases reported in over 80 countries by 2023. Arnaud Fontanet also highlights the role of deforestation, linked to global warming, in accelerating the exchange of viruses between animals, increasing the risk of pandemics. Food insecurity is another major indirect consequence. Temperature variations and extreme climatic events disrupt agricultural systems, leading to malnutrition and food-borne diseases. The Lancet study points out that climate change exacerbates food insecurity by reducing agricultural yields, labor capacity and access to water, while disrupting supply chains and compromising marine resources. Water scarcity, exacerbated by heat waves, leads to dehydration and heat-related illness, particularly affecting vulnerable communities, as the Research Institute points out.

In addition, air pollution, whose health effects are comparable to those of tobacco according to experts, is exacerbated by climate change, increasing the risk of respiratory diseases, cardiovascular accidents, diabetes and cancers. While 99% of the world's population breathes air that exceeds WHO limits and : “12% to 20% of new cases of respiratory disease in children and 7% to 13% in adults are attributable to prolonged exposure to air pollution”, explains Sylvia Médina, epidemiologist and coordinator of the air and health program at Santé publique France.

Climate change is weakening healthcare systems. It leads to malfunctions in essential services such as electricity and water, disruptions to roads and difficulties in accessing healthcare infrastructures. It delays patient care, with fatal consequences.

Yendoumi K.

 Source : “ Medisite ”