Washington, May 5 (Inditop.com) Reasonable worst-case scenarios for global warming could lead to deadly temperatures for humans in coming centuries, says a new research.
Researchers for the first time have calculated the highest tolerable “wet-bulb” temperature and found that this temperature could be exceeded for the first time in human history in future climate scenarios if greenhouse gas emissions continue at their current rate.
Wet-bulb temperature is equivalent to what is felt when wet skin is exposed to moving air. It includes temperature and atmospheric humidity and is measured by covering a standard thermometer bulb with a wetted cloth and fully ventilating it.
The researchers calculated that humans and most mammals, which have internal body temperatures near 98.6 degrees Fahrenheit, will experience a potentially lethal level of heat stress at wet-bulb temperature above 95 degrees sustained for six hours or more, said Matthew Huber, Purdue University professor of earth and atmospheric sciences who co-authored the paper.
“The highest wet-bulb temperatures ever recorded were in places like Saudi Arabia near the coast where winds occasionally bring extremely hot, humid ocean air over hot land leading to unbearably stifling conditions, which fortunately are short-lived today,” added Huber.
While the Intergovernmental Panel on Climate Change’s central estimates of business-as-usual warming by 2100 are seven degrees Fahrenheit, eventual warming of 25 degrees is feasible, he said.
“We found that a warming of 12 degrees Fahrenheit would cause some areas of the world to surpass the wet-bulb temperature limit, and a 21-degree warming would put half of the world’s population in an uninhabitable environment,” Huber said.
Steven Sherwood, the professor at the Climate Change Research Centre at the University of New South Wales, Australia, who is the paper’s lead author, said prolonged wet-bulb temperatures above 95 degrees would be intolerable after a matter of hours.
“The wet-bulb limit is basically the point at which one would overheat even if they were naked in the shade, soaking wet and standing in front of a large fan,” Sherwood said. “Although we are very unlikely to reach such temperatures this century, they could happen in the next.”
“These temperatures haven’t been seen during the existence of hominids, but they did occur about 50 million years ago, and it is a legitimate possibility that the Earth could see such temperatures again,” Huber said, according to a Purdue release.
These findings are slated for publication in the May 6 issue of the Proceedings of the National Academy of Sciences.
