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: They also found that dangerous bouts of wet-bulb temperatures of over 27°C (80.6°F) have more than doubled since 1979. These extreme temperatures were not found in previous studies because occurrences were brief and highly localized, concentrated near the Persian Gulf, South Asia and the Gulf of California. "That these conditions are already occurring, and that people didn't realize they were already occurring gives extra incentive for figuring out how to adapt," said Raymond, who largely performed this research as a doctoral student at Columbia before beginning post-doctoral work at NASA's Jet Propulsion Laboratory. To keep cool, humans shed excess heat through sweat, which evaporates into the air. High humidity prevents sweat from evaporating as readily, making humid heat more dangerous than dry heat. Without the opportunity to cool off, people can suffer from elevated heart rate, high blood pressure and even organ failure and death. Wet-bulb temperature is a measure of heat and humidity that expresses how human bodies will experience the temperature. It is so named because it is calculated by wrapping the bulb of a thermometer in a wet cloth. In low humidity, water will evaporate from the cloth, carrying away heat and cooling the thermometer in the same way sweat cools the human body. In these conditions, the wet-bulb temperature will be lower than the air temperature.