Story at a glance:
- Dangerous temperature and humidity levels can be reached when the human body can no longer sweat to cool itself down.
- This may occur when humidity is above 95 percent and temperatures are at least 88 degrees F.
- The “feels like” weather indexes are the closest things to measuring so-called wet bulb temperatures in weather reporting.
The heat wave in the Northwest is responsible for claiming the lives of more than 100 people, with experts saying this is a phenomenon that was supposed to happen in the mid-21st century.
Dangerous wet bulb temperatures occur when the human body can no longer sweat to cool itself down at humidity above 95 percent and temperatures are at least 88 degrees Fahrenheit, according to the study.
At that point, even healthy people can be victimized, regardless of what state they are in.
“Even if they’re in perfect health, even if they’re sitting in the shade, even if they’re wearing clothes that make it easy in principle to sweat, even if they have an endless supply of water,” Lamont Research Professor Radley Horton of Columbia University’s Lamont-Doherty Earth Observatory told Vice. “If there’s enough moisture in the air, it’s thermodynamically impossible to prevent the body from overheating.”
His research, which the National Oceanic and Atmospheric Administration (NOAA) supports, proves the government does acknowledge that weather conditions can determine whether someone is healthy or spontaneously dies.
“Some locations have already reported combined heat and humidity extremes above humans’ survivability limit,” a NOAA press release stated.
NOAA is supporting projects looking closer into these dangerous conditions.
Perspiration is a natural function of the body that helps prevent people from overheating, producing fluids that are secreted by the sweat glands in the person’s skin. As the sweat evaporates, it draws heat away from the body.
But the atmosphere has a limit as to how much moisture it will absorb, and it can’t be too humid.
In humid conditions, sweat is less likely to evaporate into the atmosphere as opposed to dry conditions, Horton told Vice. Dry heat, like that of the desert, is more comfortable than humid heat for this reason.
“We need a differential between the human body and the environment, and if the air is already holding as much moisture as it can, you don’t have that gradient,” Horton said. “Your body’s not able to get the atmosphere to take that moisture from it.”
Matthew Lewis, director of communications at housing advocacy group California YIMBY, urges weather broadcasts to include wet bulb indices in temperature announcements — “as a matter of public service” — the way some do air quality and humidity metrics.
Horton says “feels like” measurements are the closest thing to wet bulb forecasts.
“The very fact that there isn’t one standard that everyone uses, and that most people couldn’t explain exactly what these mean suggests that we could do more,” Horton told Vice.
Correction: This story has been updated to better explain wet bulb temperature.
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