Title: Humid Heat Already Exceeding Human Tolerance in Some Regions | American Association for the Advancement of Science
Headings: Humid Heat Already Exceeding Human Tolerance in Some Regions
Humid Heat Already Exceeding Human Tolerance in Some Regions
Content: In high humidity — when the air is more saturated with water vapor — the water cannot evaporate as easily so the cloth stays hot. If the wet cloth cannot cool below the air temperature, neither can human skin. "Physiologically," Raymond said, "there's a point when heat and humidity will become not just uncomfortable, but actually impossible to acclimate to." In 2010, scientists Steven C. Sherwood and Matthew Huber suggested that a person in perfect health, at total rest, in full shade and with unlimited water will still overheat if heat and humidity combine to stop sweat from cooling their skin below 35°C (95°F). Since these ideal conditions are rarely realized, even lower wet-bulb temperatures are dangerous. The 2003 European heatwave and the 2010 Russian heatwave, for instance, each killed tens of thousands of people with wet-bulb temperatures no higher than 28°C (82.4°F). Most climate scientists believed wet-bulb temperatures never rose above 35°C, and never would until the effects of global warming grew stronger later in the 21 st century. But these temperatures are already occurring, said Raymond and colleagues. Researchers had not yet noticed them because of a quirk in how global climate researchers study data from individual weather stations. Computer climate models use and project weather data as if weather stations were organized in a neat grid around the planet and as if they collect data at synchronized time intervals.