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• DOES HUMIDITY MAKE WEATHER FEEL WARMER PLUS

Many of these hot spots, which can be seen in this interactive map, have already been flagged by models. Weather stations in these places recorded approximately 1000 incidents registering at 31☌, while the wet bulb temperature broke 33☌ about 80 times, according to the researchers. Areas in the Caribbean, West Africa, and southern China also had extreme readings. They include Mexican towns near the Gulf of Mexico and the Gulf of California, and the coastal city of San Francisco in Venezuela. Weather stations in several other places stood out. And in 2017, wet bulb conditions topped 30☌ 1000 times- more than double the number in 1979, they write today in Science Advances. They discovered a handful of individual spots-including shorelines along the Persian Gulf and river valleys in India and Pakistan-had crossed the 35☌ wet bulb threshold, though only for an hour or two at a time. To find out, he and his colleagues combed through 39 years of hourly data from weather stations on six continents, dating back to 1979. Raymond wondered whether that might obscure specific hot spots where geography and weather are already conspiring to create intolerable conditions. Likewise, analyses of past weather data assess conditions over grids of more than 700 square kilometers, potentially missing localized spikes.

But their models estimate temperatures for relatively large swaths of land. In the heat wave that ravaged Europe, wet bulb temperatures hit 28☌.Ĭlimate change will likely make these conditions more common in places such as southwest Asia, India, and China, researchers say. Although that temperature might seem low, it equates to almost 45☌ at 50% humidity, and what it would feel like 71☌ using the U.S.

DOES HUMIDITY MAKE WEATHER FEEL WARMER PLUS

To measure the effects of heat plus humidity, scientists use wet bulb temperatures-the lowest temperature to which air can be cooled via evaporation.Īt wet bulb temperatures above 35☌, researchers estimate that even fit people will overheat and potentially die within 6 hours. Humidity is deadly when it prevents the evaporation of sweat-a remarkably efficient way for the human body to cool itself. A 2003 heat wave, for example, killed more than 70,000 people in Europe, when outdoor temperatures reached more than 40☌. "Previous studies projected that this would happen several decades from now, but this shows it's happening right now," says Colin Raymond, a postdoctoral researcher at NASA's Jet Propulsion Laboratory who led the study. An analysis of 4 decades of data from thousands of weather stations shows that a handful of hot spots around the globe are experiencing a potentially lethal mix of heat and humidity-something most of these places weren't expected to experience until midcentury. From the shores of the Persian Gulf to the foothills of Mexico's Sierra Madre Occidental mountains, hot weather is reaching levels humans can't endure.