Heatwaves carry air that is too hot and too humid to survive, researchers report in the journal Science Advance.
LONDON UK (Science Advance) – Studies warn of deadly heatwaves around the world. Scientists have repeatedly warned of lethal temperature and humidity conditions caused by heatwaves in a world battered by climate change. Bad news: the future has caught up with us, and deadly heatwaves have already arrived.
Experts have reviewed local records to identify thousands of episodes where the combination of high temperatures and high humidity has risen to levels where humans could not survive for long, in Asia, Africa, North and South America, and Australia.
There have already been a dozen such episodes in the Persian Gulf, a region that researchers warned years ago could be deadly for outdoor workers.
According to the researchers’ publication in the journal Science Advance, these outbreaks of suffocating heat and humidity have so far been limited to focused areas. They have lasted only a few hours, although they are increasing in frequency and intensity.
There are many ways in which extreme heat can cause death. In its purest form, a species adapt to maintain a stable temperature by shivering when it is cold and sweating when it is too hot. It can be overwhelmed by very high temperatures or in conditions where the body can no longer lose heat because the air is too humid to evaporate the sweat.
Scientists measure such hazards by what they call a “wet bulb” temperature, and even the strongest and best-adapted humans cannot work safely outdoors when it reaches 32 degrees Celsius.
Potentially fatal readings were identified in hourly reports from 7,877 weather stations between 1979 and 2017. Such temperatures have already reached dangerous levels in places like Saudi Arabia; Doha, in Qatar, in the United Arab Emirates; in Texas, Louisiana, Mississippi, Alabama, and Florida, in the United States; India and Bangladesh; southern China, northwest Australia, and Iran.
Researchers began warning years ago of the threat of extreme heat and humidity in a world where humans continue to burn fossil fuels and increase concentrations of greenhouse gases in the atmosphere. Repeated studies have confirmed the reality.
Previous studies projected this would happen in several decades. “Still, it’s happening now,” said Colin Raymond, who completed the research at Columbia University’s Lamont-Doherty Earth Observatory but is now at NASA’s Jet Propulsion Laboratory.
“The timing of these events will increase, and the areas they affect will grow, in direct correlation with global warming,” they concluded.
