Malaria, dengue fever, encephalitis, Lyme disease… Up to 58% of infectious or allergic diseases that affect humanity have, at some point, been aggravated by climatic hazards linked to the emission of greenhouse gases ( GES). That is 218 of the 375 known human diseases linked to pathogens. Conversely, 16% of these illnesses were sometimes alleviated. These are the main conclusions of an American study, published on August 8 in the scientific journal Nature Climate Change.
The authors, coordinated by Erik Franklin, a geographer from the University of Hawaii, scrutinized the impact, on human diseases caused by pathogens, of nine climatic upheavals linked to GHGs: atmospheric warming, but also drought. , heat waves, wildfires, extreme rainfall and flooding, warming oceans, increased storms and rising sea levels. They also analyzed another consequence of these emissions, the modification of terrestrial vegetation cover.
“This bibliographical analysis seems to me to be quite serious.estimates the virologist Yannick Simonin, of Inserm, at the university of Montpellier. The rate of 58% must be put into perspective, but it has the merit of giving an order of magnitude and alerting to the importance of climate change in the increase in human diseases linked to pathogens, whether these diseases are emerging or more old. »
The Hawaiian team first searched the Google Scholar database for all published studies that presented concrete examples of pathogenic diseases affected by one or other of these climatic risks. In total, the researchers reviewed more than 77,000 titles. They retained 830 of them, which reported an explicit climatic risk (heat waves, floods, etc.) affecting a given disease (malaria, dengue fever, etc.), in a region and/or over a given period.
More and more zoonoses
Results: 58% of known human pathogenic diseases (i.e. 218 out of 375) have been affected, at one time or another, by at least one of these climate changes. Of these, 160 diseases have been aggravated by warming, 122 by excessive rainfall, 121 by floods, 81 by droughts, 71 by storms, 61 by land cover changes, 43 by ocean warming, 21 by fires, 20 by heat waves and 10 by sea level rise.
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