COP28 - Climate Change, a Threat to Human Health

Humanity is facing increasingly numerous threats, many of which are self-inflicted, and nature seems less willing to aid humans. Experts argue that we have reached a point of no return, and if humanity does not realize the gravity of the situation, the future will not be bright at all. Climate change poses a multiple threat to human health, and the United Nations Climate Action Conference (COP28), starting on Thursday, will dedicate, for the first time in the event's history, a day to this subject.

"To avoid catastrophic effects on health and prevent millions of deaths," the World Health Organization, along with other health experts and environmental organizations, asserts that the average temperature increase on Earth must be limited to 1.5 degrees Celsius, the ambitious goal of the Paris Agreement. However, the planet is currently heading towards a warming of 2.5 to 2.9 degrees Celsius by 2100, according to the UN. Although no human being is immune to the health effects, the most vulnerable and disadvantaged, including children, women, the elderly, migrants, or inhabitants of underdeveloped countries - which emit the least amount of greenhouse gases - are exposed more rapidly and with greater impact, according to experts.

The year 2023 is already forecasted to be the hottest ever recorded. As global warming continues, more frequent and intense heatwaves will increasingly impact the human body. In 2022, Earth's inhabitants were exposed, on average, to 86 days of potentially lethal temperatures. The most vulnerable individuals pay the heaviest toll. The number of people over 65 who lost their lives due to heatwaves increased by 85% in the periods 1991-2000 and 2013-2022, according to a landmark report published this week in the medical journal The Lancet. In Europe alone, heat caused over 70,000 deaths last summer, researchers stated this week, following a revised estimate increase from the previous figure of 62,000 victims. Nearly five times as many people globally are at risk of dying from extreme heat effects by 2050, according to a "countdown" published by The Lancet. Increasingly frequent droughts also expose millions of people to famine. From the perspective of a 2-degree Celsius warming by 2100, millions more people than at present will be affected by moderate to severe food insecurity by mid-century. Other extreme weather events, such as storms, floods, and fires, cause deaths or promote the onset of conditions.

Exacerbated by climate change, air pollution increases the risk of respiratory diseases, cardiovascular accidents, diabetes, or cancer, and, according to experts, has comparable, or even more severe, effects than smoking or alcohol. Thus, the atmosphere contains gases, heavy metals, fine particles, mainly resulting from fossil fuels, which can pass through the lung barrier and enter the bloodstream. Although more visible during peak pollution periods when respiratory infections and allergies increase, the most harmful effects are associated with long-term exposure. Over four million: this is, according to the WHO, the number of premature deaths caused by outdoor air pollution globally every year. As a ray of hope, these premature deaths have decreased by almost 16% since 2015, mainly due to reduced coal consumption, according to The Lancet's "countdown."

Climate disruptions - temperature and precipitation changes - also intensify infectious and parasitic diseases. This particularly concerns new areas affected by mosquitoes, birds, but also mammals involved in epidemics caused by viruses (dengue, chikungunya, Zika, West Nile virus), bacteria (plague, Lyme disease), animals, or parasites (malaria). The spread of dengue fever could increase by 36% with a global warming of 2 degrees Celsius by 2100, according to The Lancet report. And, with the warming of the oceans, more coastal areas will become conducive to the transmission of the Vibrio bacterium, which causes cholera. Storms and floods can create stagnant water, favorable for mosquito breeding, while heatwaves favor waterborne infections.

Anxiety, depression, or post-traumatic stress - climate disruptions also pose a risk to mental health, especially for individuals with clinical pathologies, according to specialists. The direct effects of natural disasters and heatwaves are compounded by indirect effects, such as eco-anxiety, which particularly affects young people.