What is the importance of wet-bulb temperatures in a warming world?

The summer is here and the heat is upon us. Much of India experiences hot weather, exposing over a billion people to tough conditions. While you might be tracking the daily temperatures of your region that can be seen in weather forecasts, that might not be a fair reflection of the conditions.

The temperatures we see in weather forecasts are called air temperatures, also referred to as dry-bulb temperatures by meteorologists. Humidity, which plays a big role in how we experience heat, is not factored into air temperatures.

What is wet-bulb temperature?

Wet-bulb temperatures, on the other hand, combine the dry air temperature that we can see on a thermometer with humidity. It is for this reason that wet-bulb temperatures are a better measure of heat-stress conditions on humans in direct sunlight.

The name is a reflection of how this temperature is measured. When a wet cloth is slid over the bulb of a thermometer, the thermometer cools down due to water evaporating from the cloth. This lower temperature is the wet-bulb temperature and cannot go above air temperature.

The evaporating water cooling down the thermometer is akin to how our hodu temperature is lowered when we sweat. The sweating helps, however, only when the humidity in the surrounding air is low.

Sweating and humidity

If the humidity is high then it means that the air is already more saturated with water. As a result, less evaporation will occur and the wet-bulb temperature will be closer to the dry temperature. In such a scenario where the humidity is very high, sweating might not cool you as the sweat needs to evaporate off our skin for cooling to occur.

While it was long believed that a wet-bulb temperature of 35 degree Celsius was the maximum a human could endure for extended durations, a study in ?0?? suggested that it could he much lower – around 31 degree Celsius. With the world’s temperatures fast rising, extreme weather events, including heatwaves, are being encountered far more often in a warming world.

When the wet-bulb temperature in your region is high, it is important to take good care of yourself. If you are forced to be outside for a considerable length of time, then it is recommended that you wear a hat and lightweight, loose-fitting, light-coloured clothes. It goes without saying that you should try to take frequent breaks in areas with shade and keep yourself hydrated by taking plenty of fluids.

Picture Credit : Google

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