As climate change intensifies, people around the world are learning firsthand how dangerous high temperatures can be. But prolonged heat becomes even more dangerous, and deadly, when paired with high humidity — a one-two punch known as a humid heat wave. Scientists report that humid heat waves have intensified rapidly over recent decades and are projected to worsen, raising the risk of significantly more heat-related mortalities. But quantifying the origins of these extreme weather events has remained challenging. A new study published in Nature Geoscience has identified and quantified a likely cause. It traced a strong connection between coastal waters heated by climate change and the development of humid heat waves that spread out over large areas inland — an effect especially pronounced in the tropics. “Compared with mid-to-high latitudes, the tropics encompass most [humid heat wave] high-risk areas and exhibit stronger land-ocean linkages, highlighting the critical role of tropical oceans,” according to the study conducted by researchers from Germany’s Potsdam Institute for Climate Impact Research (PIK), Princeton University in the U.S., and Sun Yat-sen University in China. Humid heat waves — periods when high temperatures couple with high humidity — are particularly dangerous for human survival, Fenying Cai, study lead author with PIK, told Mongabay in a phone interview. Previous research indicated that even young, healthy people can experience dangerous heat stress when a wet-bulb thermometer (measuring ambient temperature plus relative humidity) has readings exceeding 31° Celsius (87.8° Fahrenheit), a point at which the body can no longer effectively…This article was originally published on Mongabay

From Conservation news via This RSS Feed.