Extreme heat, air pollution, infectious diseases or mental health: climate change is a multiple and growing threat to human health, to the point that COP28, which opens Thursday, will dedicate a day to this for the first time. subject.
“To avoid catastrophic effects on health and prevent millions of deaths”, we must limit the average rise in temperature on Earth to 1.5°C, the most ambitious objective of the Paris Agreement, argues the World Health Organization (WHO), along with other health experts and environmental organizations.
But the planet is currently heading towards warming of 2.5°C to 2.9°C by 2100, according to the UN.
If no human is safe from health risks, the most vulnerable and disadvantaged are exposed faster and harder, according to experts: children, women, the elderly, migrants or inhabitants of countries the least developed — the lowest emitters of greenhouse gases.
Heat waves
The year 2023 is already shaping up to be the hottest on record. And, as global warming continues, more frequent and more intense heat waves promise to take ever greater toll on the human body.
In 2022, Earthlings have been exposed, on average, to 86 days of life-threatening temperatures.
The most vulnerable pay the heaviest price. Thus, the number of over 65s who died due to heat jumped by 85% between the years 1991-2000 and 2013-2022, according to a reference report published this week by the medical journal The Lancet.
In Europe alone, heat caused more than 70,000 deaths last summer, researchers said this week, revising upwards the previous estimate of 62,000 victims.
Nearly five times more people are likely to die globally from extreme heat by 2050, according to the World’s ‘countdown’ Lancet.
More frequent droughts are also exposing millions of people to hunger. With 2°C warming by 2100, an estimated 520 million additional humans would find themselves moderately or severely food insecure by mid-century.
And other extreme weather events, such as storms, floods or fires, cause death or illness.
Air pollution
Nearly 99% of the world’s population breathes air that exceeds the limits set by the World Health Organization.
Accentuated by climate change, air pollution increases the risk of respiratory diseases, cardiovascular accidents, diabetes or cancer and has, according to some experts, effects comparable, or even greater, than those of tobacco or tobacco. ‘alcohol.
The cause: the presence in the air of gases, heavy metals, particles and dust, mainly resulting from fossil fuels, which can cross the barrier of the lungs and enter the blood.
Notable during pollution peaks, when respiratory infections and allergies surge, the most harmful effect on health is linked to long-term exposure.
More than four million: according to the WHO, this is the number of premature deaths caused by outdoor air pollution each year in the world.
In glimmers of hope, these premature deaths have fallen by almost 16% since 2005, mainly thanks to less coal consumption, according to the “countdown” of the Lancet.
Infectious diseases
By modifying temperature and precipitation, climate change also increases infectious and parasitic diseases.
This is particularly linked to new areas of penetration of mosquitoes, birds and even mammals involved in epidemics caused by viruses (dengue, chikungunya, Zika, West Nile virus, etc.), bacteria (plague, Lyme disease, etc.), animals or parasites (malaria, etc.).
Dengue transmission could jump 36% with global warming of 2°C by 2100, says report Lancet. And, with warming oceans, more coastal areas are conducive to the transmission of the vibrio bacteria, which causes cholera.
Storms or floods can also leave stagnant water, favorable for mosquito breeding, and heat waves increase water-borne infections.
Mental Health
Anxiety, depression or even post-traumatic stress, climate change also represents a risk for mental health, even more so among people suffering from psychological pathologies, according to specialists.
In addition to the direct repercussions of natural disasters or heatwaves, there are indirect effects, such as ecoanxiety, particularly among young adults.