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Increased Heat Risk Due To Humidity

Urban regions are experiencing greater heat stress as global temperatures hit record-high levels. Compared to nearby rural terrain, cities are typically dryer and warmer. Urban humid heat is a further problematic element in the Global South.

A study by Yale School of the environment

Researchers from the Yale School of the Environment, Lee, YSE, and Keer Zhang, recently published a study in Nature that used observation data and an urban climate model calculation to examine the combined impact of humidity and temperature on urban heat stress. Researchers discovered that the local climate affects the burden of heat stress and that a humidifying influence can negate the cooling effects of flora and trees. Accordingly, they were driven to look into the problem because of a number of factors, including the fact that a sizable portion of the world’s population lives in cities.


Air temperature and air humidity

The researchers created a theoretical framework to explain how urban land affects both air temperature and air humidity, and they demonstrated that, in contrast to other heat indices that prioritize temperature over humidity, the wet-bulb temperature measures heat stress by giving equal weight to both effects. To quantify humid heat, wet-bulb temperature adds humidity to the temperature of the dry air. The authors acknowledge that the study’s findings present significant issues.