infectious diseases, famines… Yes, climate change is also disrupting global health

Don't forget: humans are part of biodiversity. And therefore does not escape the crisis that threatens it. A few days before the opening of COP 29, this November 11, the World Health Organization (WHO) recalled that the current climate upheaval is “a question of life and death”. Forcing world leaders, meeting in Baku (Azerbaijan) until November 22, to address the health threat that disruption represents for humanity. However, despite the necessity, this is only the second time that the subject has been raised during a Cop.

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The deadly nature of the disruption has, however, been established. Still according to the WHO, by 2030, the climate crisis could cause 250,000 additional deaths per year. An estimate which could be below reality, certain effects of the disruption being particularly complex to understand. Heat waves, extreme rains, droughts… These events, expected to be more and more frequent and intense, will cause thousands of deaths in all regions of the globe, furthermore promising to cause epidemics and famines. While CO2 emissions from the combustion of fossil fuels will reach a record again this year despite warnings, new causes of death will increase inexorably in the years to come.

Deadly heat

France painfully understood this during the heatwave of 2003: excessive temperatures can in themselves prove deadly. Around 15,000 excess deaths were recorded that summer. Since then, heat victims have been piling up. Heatwaves are even the extreme climatic events associated with the highest human burden in mainland France, according to a Public Health France report published last year.

And even outside of heatwave episodes, high temperatures carry significant risks: during the summer periods from 2014 to 2022, nearly 33,000 deaths are attributable to heat between June 1 and September 15 of each year, including 23,000 deaths. people aged 75 and over.

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In August, the WHO reported 489,000 heat-related deaths recorded each year by the WHO between 2000 and 2019, including 175,000 in Europe. Thus, the number of people over 65 who have died due to heat has jumped by 167% worldwide since the 1990s. And, for those who still doubt the responsibility of industrial activities, recent research puts it at 37%. from heat-related deaths to human-induced climate change.

What do you die of when it's too hot? Excessive heat can lead to kidney problems, strokes, cardiovascular and respiratory diseases, organ failure and sometimes death. This risk now concerns most countries, except, unsurprisingly, those furthest north and furthest south, in which the rise in mercury still remains below dangerous temperatures for the body. More than 70% of the world's working population is exposed to excessive heat.

Multiple disasters

The recent floods in Spain are irrefutable proof: extreme events are increasingly deadly, and globally affect all regions of the world. These can be devastating storms, landslides, etc. Although extreme precipitation is causing more and more victims, they are not the only disasters to prove deadly. On the other side of the Atlantic, the United States and Cuba are still dealing with the consequences of recent hurricanes, notably Hurricane Milton which caused more than ten deaths.

Another figure: 45,000 deaths were caused by floods, storms, heat and cold waves, forest fires and landslides between 1980 and 2021 in Europe, according to figures published by the Agency European Environment Commission in June 2023 – which does not include deaths caused by heat waves.

READ ALSO: One in 4 French people affected: like Spain, France very vulnerable to flooding

If the least developed countries often face increased risk, particularly due to the inadequacy of urban infrastructure to climatic hazards, the Spanish death toll of more than 220 deaths shows that this risk must be taken into account throughout the world.

Microbe paradise

A warmer, sometimes more humid world is a haven for viruses, bacteria and parasites. Result: the greater spread of infectious and parasitic diseases. The cause in particular is the expansion of areas where birds or mammals are present, but especially mosquitoes, capable of transmitting viruses (dengue, chikungunya, Zika, West Nile virus, etc.), bacteria (plague, Lyme disease, etc.). ), or parasites (malaria, etc.). These diseases, called vector-borne since transmitted by a “vector”, are already responsible for more than 700,000 per year. Balance sheet which risks increasing.

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Rising temperature alone increased the global transmission potential of the tiger mosquito, the vector of dengue fever, by 42.7% between the 1950s and the 2010s, according to the Lancet. And 2023 recorded more than five million cases of dengue, transmitted by this mosquito, a new record. Especially since heavy rains, or even floods, can be a boon for the tiger mosquito: they can leave stagnant water, favorable to its reproduction and therefore its proliferation.

These stagnant waters are also the second vector of the explosion of the risk of infection, since in addition to being a breeding ground for mosquitoes, they can become reservoirs for communicable diseases – cholera, typhoid and diarrhea. Low-income countries and small island developing states (SIDS) face the most severe health impacts, with health measures more complex to establish and sanitation systems far less secure.

Increasingly widespread famines

Droughts, floods and other extreme weather events increase the risk of famine. Already, because they reduce agricultural yields, or even devastate crops, depriving populations of food resources. Then, because they lower the quality of crops and foodstuffs and thus make water and food diseases more frequent. 600 million suffer from foodborne illnesses each year, with 30% of foodborne deaths affecting children under 5 years old, according to the WHO.

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Thus, in 2020, 770 million people suffered from hunger, mainly in Africa and Asia, and the toll will increase in the coming years, with climate change exacerbating the food and nutritional crises.

Air pollution

Here too, it is difficult to find regions of the world that are completely spared, even if it is now obvious that large urban and industrial centers are the most affected by this other climate killer: pollution. The latter is in fact accentuated by climate change, and increases the risk of respiratory diseases, cardiovascular accidents, diabetes or cancer. To the point, according to some experts, of being as dangerous, or even more so, than tobacco or alcohol.

Nearly 99% of the world's population breathes air exceeding the limits set by the WHO. At the beginning of November, Lahore, Pakistan's second city, recorded a concentration of PM2.5 microparticles in the air more than 40 times higher than the level deemed acceptable by the WHO.

Notable during pollution peaks, the effect on health is all the greater the longer the exposure exists. More than seven million premature deaths are, according to the WHO, caused by air pollution each year worldwide, pollution which also causes preterm births and low birth weight.

A glimmer of hope, the number of people killed by air pollution generated by fossil fuels fell by around 7% worldwide between 2016 and 2021, “mainly thanks to the closure of coal-fired power stations”according to a report by The Lancet. Still light to ensure the salvation of humanity.