Heat stress may affect 1.2 billion people annually by 2100, according to a Rutgers study.
This study on heat stress titled "Escalating global exposure to compound heat-humidity extremes with warming" applied a measure of heat stress that takes into account temperature, humidity and other environmental factors, such as sun angle, wind speed, and solar and infrared radiation.
The researchers examined how combined extremes of heat and humidity intensify on a warming Earth. The researchers used 40 climate simulations to acquire statistics on rare events.
Published in the journal Environmental Research Letters, the study revealed that annual exposure to extreme heat and humidity may affect areas that have 500 million people if the planet warms by 1.5 degrees Celsius (2.7 degrees Fahrenheit).
Moreover, the heat of the planet already increased by about 1.2 degrees (2.2 degrees Fahrenheit).
The study showed that an estimated 1.2 billion people would experience 3 degrees Celsius (5.4 degrees Fahrenheit) of warming.
"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," said senior author Robert E. Kopp, director of the Rutgers Institute of Earth, Ocean, and Atmospheric Sciences and a professor in the Department of Earth and Planetary Sciences in the School of Arts and Sciences at Rutgers University-New Brunswick.
"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," said lead author Dawei Li, a former Rutgers post-doctoral associate now at the University of Massachusetts.
