Climate change can make most human diseases worse

Nicole Wetsman - Yesterday 
The Verge

Polio is back, monkeypox isn’t slowing down, COVID-19 is still around — and now there’s more not-so-good news on the infection front: over 200 human diseases could get worse because of climate change, according to a new study.


© Photo by Stefan Jaitner/picture alliance 

Researchers have known for a long time that the changing climate affects disease. Warmer temperatures can make regions newly hospitable to disease-carrying mosquitoes, while floods from more frequent storms can carry bacteria in their surges of water.

Most research, though, only focused on a handful of threats or one disease at a time. The new study, published in Nature Climate Change, built a comprehensive map of all of the ways various climate hazards could interact with 375 documented human infectious diseases.

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The authors reviewed over 77,000 scientific articles about those diseases and climate hazards. They found that, of those 375 diseases, 218 could be aggravated by things like heatwaves, rising sea levels, and wildfires.

The study found four main ways climate change exacerbates diseases. First, problems happen when changes cause disease-carrying animals to move closer to people. For example, animal habitats are disrupted by things like wildfires that drive bats and rodents into new areas, increasing the likelihood they’ll transmit diseases like Ebola to people. Other research shows that climate change makes viruses more likely to jump from animals to people, as happened with the coronavirus that causes COVID-19. That phenomenon also likely contributed to the 2016 Zika outbreaks.

People also move closer to disease-causing animals during climate-driven events. Diseases like cholera and Lassa fever were linked to human movement after storms and floods. Third, climate hazards also give pathogens a boost — like how disease-carrying mosquito populations grow in warmer temperatures. Finally, climate changes make people less able to cope with diseases. For example, large swings in temperature can weaken the human immune system, which might be the reason for flu outbreaks.

If you’re interested in taking a closer look at exactly all the diseases that are affected, the study authors built an interactive chart that connects every disease to the climate hazards that amplify it. So you can see, for example, how drought, fires, and floods make health problems caused by sand flies — including fevers and parasitic skin conditions — more common. Happy (or not so happy) scrolling!