A new study predicts that by the year 2100, heat stress could affect over 1.2 billion people each year.
For those who don’t know what heat stress is, it is an illness caused by exposure to extreme heat when the human body is no longer able to cool down properly through sweating. Essentially, it is what happens when our bodies are unable to maintain a healthy temperature in response to a hot environment. Symptoms range from mild ones like a heat rash or cramps to more serious ones including full blown heat exhaustion, which is more common. Heatstroke is no joke and can be fatal.
For those who are not used to the heat down here in the southern United States where I’m from, heat stress is common. I grew up in it and was taught from an early age to drink not 8 glasses of water but 16 glasses daily during the spring, summer, and early fall months.
“When we look at the risks of a warmer planet, we need to pay particular attention to combined extremes of heat and humidity, which are especially dangerous to human health.” — Robert E. Kopp, director of the Rutgers Institute of Earth, Ocean, and Atmospheric Sciences and senior author of the study published on IOP Science.
The Rutgers Institute of Earth, Ocean, and Atmospheric Sciences study predicts that heat stress caused by extreme heat and humidity will affect areas now home to 1.2 billion people by 2100 if we take into consideration current greenhouse gas emissions. Compared to today, that is more than 4 times the number of people affected and more than 12 times the number who would have been affected without any anthropogenic global warming.
“Every bit of global warming makes hot, humid days more frequent and intense. In New York City, for example, the hottest, most humid day in a typical year already occurs about 11 times more frequently than it would have in the 19th century.” — Dawei Li, University of Massachusetts and lead author
The study observed how a combination of extreme heat and humidity is increasing on a warming Earth. It used 40 climate simulations to get statistics on uncommon events and focused on a measure of heat stress accounting for temperature, humidity, and other environmental factors such as wind speed and the angle of the sun.
It found that current emission levels would result in an average temperature increase of a staggering 5.4 degrees Fahrenheit. The result would pin the burden of global emissions on 1.2 billion people in the form of extreme heat on a regular basis.
Featured image credit: NASA’s Scientific Visualization Studio.


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