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August 18, 2022
58% of infectious diseases known today are influenced in one way or another by climate change. And this is just the beginning, warn scientists.
A major concern of our societies, climate change would also be involved in the spread of pathogens that affect us directly, and very often in a negative way. This is the finding revealed by a study published on August 16 in the journal Medical News Today. This is not the first study on the subject, but this one has the advantage of quantifying the effects of 10 climatic hazards linked to greenhouse gases, such as drought, extreme precipitation, sea level or changes in land use.
277 illnesses out of 375 aggravated by the climate
For the analysis, the researchers reviewed more than 77,000 studies looking for empirical examples of climate risks impacting pathogenic diseases, such as influenza, malaria and SARS.
Ultimately, the team concluded that 58% of the 375 infectious diseases documented as affecting humanity worldwide have been impacted by climatic hazards at some point in time. Of these 286 pathogenic diseases, 277 diseases would be aggravated by at least one climatic hazard, and only 9 were mitigated by these. An observation tinged with pessimism for scientists: “There there are simply too many diseases and transmission routes for us to think we can truly adapt to climate changeevokes Dr. Camilo Mora, professor in the Department of Geography and Environment at the University of Hawaii at Manoa, and lead author of the recent scientific analysis. This highlights the urgent need to reduce greenhouse gas emissions globally “.
Concretely, how can climate change aggravate already present human pathogenic diseases? Dr. Tristan McKenzie, from the University of Gothenburg, also author of the analysis, pointed to 4 distinct mechanisms.
- Environmental changes tend to bring pathogens closer to humans, spreading them to where they live.
- Climatic hazards also bring humans closer to the cradles of pathogens, by forcing certain populations to move, for example.
- The climate and its evolution would also tend to strengthen the resistance of diseases by accustoming them to more extreme conditions.
- Finally, these same climatic hazards would tend to make us more vulnerable to infections by imposing additional stress on our body.
Analyzes that must continue: the research team specifies that it has not assessed the impact of climatic hazards on the frequency, severity or prevalence of infections.