Why does climate change lead to more diarrhea? Is it because people drink more E.Coli-contaminated water? Or does it multiply and contaminate a fixed volume of water more at warmer temperatures? Or does it contaminate more water sources somehow?

  • Just some wild theories: maybe climate change negatively affects clean fresh water availability. Maybe also E.Coli benefits from increased temperatures. When multiplying in the human body, it has a temperature of 37 degrees Celsius. When multiplying in the environment, especially in water, not so likely.
    – juhist
    Nov 13, 2022 at 13:28
  • Diarrhea comes from Contaminated water. This proliferation in the 3rd world is result lack of sanitation....
    – LazyReader
    Dec 3, 2022 at 19:46

1 Answer 1


I’m not aware of any definitive studies or reputable sources of information that directly link climate change to increased cases of diarrhea. I’d be interested to see any if anyone happens to have a link to anything along those lines.

However, it doesn’t take a rocket scientist (or a biological scientist) to see clear potential reasons as to why climate change could cause diarrhea to become more prevalent.

For example: climate change has been linked to drought and dry conditions in many areas, which lowers the water table and reduces the number of water sources available. For people who rely on rivers and other non-groundwater sources of drinking water, the lowered water levels that drought causes can turn a free-flowing river or stream into a trickle interspersed with pools of nearly stagnant water which are also much warmer than the flowing water that’s been replaced.

Stagnant water or extreme lack of current provides ideal habitat for ample populations of algae, bacteria, and various other microbes that are unable to flourish in cooler, flowing water. As the water becomes concentrated and subject to excessive water temps as it sits in the sun all day, so too do nutrients and pathogens, etc become concentrated. The abundance of nutrients in the water, warmer than usual water temperatures, and lack of circulation/oxygenation are all factors that lead to the water no longer being potable.

A spot that typically has safe drinking water due to dilution of any microbes via current, and less productive living conditions (flowing water, cooler temps, no stagnant areas to allow pathogens to thrive) , quickly can become overrun with algae, bacteria, etc…

Failure to abandon this source of water as it is negatively impacted via climate change, in favor of a cleaner source could certainly lead to more cases of diarrhea.

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    To add to this, the lack of water can also a reduction of person hygiene practices which result in the increased likelihood of people injecting microbes that would have been washed off with adequate water supplies being injected & subsequently resulting in diarrhea or other gastrointestinal conditions.
    – Fred
    Nov 14, 2022 at 9:06

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