Climate Change Leading to Rise of Wet-Bulb Temperatures Harming Human Health

  August 13, 2021

On July 1, 2021, Delhi experienced a heatwave, when the maximum temperature rose to 43.5°C. At the same time, Ganganagar, in west Rajasthan, reported India's highest temperature of 44.5°C. Some pockets of Punjab, Haryana, Chandigarh, Delhi, north Rajasthan and west Uttar Pradesh still continue to face heatwave conditions. This issue is now prevalent world over. But the world is not only getting hotter but also wetter or more humid.

We usually consider the dry-bulb temperature to describe how hot or cold a place is. Scientists, however, have been stressing upon taking into account humidity and other factors to assess how weather conditions will affect human health and activity. Humidity is measured as wet-bulb temperature. Factoring in the humidity along with the heat, called the heat index, helps us determine what the temperature actually ‘feels like’. You may have noticed this in your mobile phones and apps as well. Humidity combined with heat is deadlier for human health and well-being. Currently, one phenomenon is severely testing the human tolerance of this heat-humidity balance: climate change!

Humans with their sweat-based cooling system, have been well-designed to beat the heat. But there is a limit to the level of heat and humidity we can cope with. A wet-bulb temperature or WBT of 35°C mark is considered the maximum limit of humidity that humans can handle. Beyond this, the body can no longer effectively cool itself via perspiration.

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