Scientists say parts of planet set to be too hot to live in

Extreme heat and humidity are increasing across the globe, threatening millions of lives and economies in places where it could become fatal to work outdoors.

Parts of Australia, India, Bangladesh, the Persian Gulf, China, Mexico and the United States have experienced hundreds of previously rare incidents of extreme heat and humidity since 1979, said a study in the journal Science Advances.

These punishing conditions have lasted only one to two hours but climate change is likely to prolong them to about six hours at a time by 2060 and expand the affected areas, said lead author Colin Raymond.

“That’s kind of a conservative estimate but that’s still earlier than anyone else had projected,” said Raymond, who did the research as a PhD student at Columbia University and now works for NASA.

Moist, humid conditions make it harder for people to sweat away excess heat, leading to health risks including heat stroke, which can kill or disable victims who go untreated, according to the US Centers for Disease Control and Prevention.

Many scientists are examining the potential increase in extreme heat and its impact on economies and health, with mental health problems set to soar as people have trouble sleeping and working.

‘Near-unlivable heat’

Limiting warming to 1.5 degrees Celsius above pre-industrial times is the most ambitious goal of the 2015 Paris Agreement on climate change and world temperatures have already risen by 1.2 degrees Celsius.

A separate paper published this week by the Netherland’s Wageningen University warned of “near-unlivable” heat of above 29 degrees Celsius for a third of humanity by 2070.

In the Columbia University-led study, data from nearly 8,000 weather stations showed readings approaching or exceeding 30 degrees Celsius have doubled since 1979, and two — in the Persian Gulf and Pakistan’s Indus River Valley — reported values above 35 degrees Celsius.

“We may be closer to a real tipping point on this than we think,” Radley Horton, co-author and climate scientist at Columbia’s Lamont-Doherty Earth Observatory, said in a statement. The highest readings were in parts of Saudi Arabia, Qatar and the United Arab Emirates, home-to-some 3 million people.

Surviving in these conditions would require adapting buildings and human behavior, which includes minimizing outdoor labor.

This could severely disrupt farming and commerce, with many poor people unable to afford air conditioning, said Horton.

The study focused on “wet bulb” temperatures, which scientists say reflect the combined effects of temperature and humidity, a more useful indicator of heat stress.