Despite water, shade or cool clothing, after a certain point the heat can kill. Wet bulb temperature is the reason

The heat wave continues its torture as the mercury rises in an unprecedented way. India suffers from excessive sunshine. Banda in eastern Uttar Pradesh recorded a jaw-dropping record high of 47.4 degrees Celsius for April, with many other places also recording record high temperatures for the month.

Climatologists are concerned about the effects of this heat wave. Not only because it indicates an increased cycle of the worst weather effects that climate change brings. But also because there is only a point to which man can adapt to these changes.

According to reports, heat waves are the worst type of natural disaster. Indeed, they disproportionately affect socially vulnerable communities, and are only expected to get worse. When the severity and frequency of high heat increases, there is a marker to determine the possibility of death, which is wet bulb. News18 dives into the concept and what it means amid India’s scorching heat.

What is the wet bulb temperature?

The amount of heat and humidity people can tolerate is one of the most critical hard limits on the effects of a heat wave. This is measured by scientists using the wet bulb temperature, which is the highest temperature at which water does not evaporate in a given amount of moisture. It acts as an indicator of how efficiently the human body can regulate its temperature. The highest wet bulb temperature acceptable to humans is 95°F (35°C) for six hours. Beyond this point, even healthy people begin to develop serious, often fatal health problems, according to a report by Voice.

On several occasions, parts of Iran, Pakistan and India, all densely populated countries, have approached or exceeded this level. Climate change is increasing the number and severity of extreme heat events as global average temperatures rise. Since 1979, the number of areas on the planet reaching the human wet bulb temperature limit has doubled, the report further explains.

The wet bulb temperature, in terms of the human body

Sweating is one of the body’s main cooling mechanisms when there is not enough moisture in the air. Our body controls heat by releasing it in the form of water, which evaporates on the surface of the skin; for this water to evaporate into the atmosphere, it must flow in a gradient of high to low vapor pressure, explains the insider in a report.

Sweating alone does not cool the body; heat must be removed from the body by evaporation. The pressure differential that would normally allow perspiration to evaporate does not exist when there is enough water vapor in the environment. Without a duct, sweat clings to the body and heats up indefinitely, increasing the risk of overheating and failure of the body’s basic systems.

Wet-bulb temperatures can reach a threshold where they are “beyond human tolerance,” as Radley Horton, Lamont Research Professor at Columbia Climate School, described in a 2020 study in the peer-reviewed journal. of Science Advances reading. His research indicates that a wet bulb temperature of 35 degrees Celsius (95 degrees Fahrenheit) is the upper physiological limit. A temperature over 35 degrees Celsius is deadly, the report says.

And there is no escaping such effects…even with water and shade at will.

“Even if they are in perfect health, even if they sit in the shade, even if they wear clothes that in principle facilitate perspiration, even if they have an inexhaustible supply of water”, said Horton. as the report says.

“If there is enough moisture in the air, it is thermodynamically impossible to prevent the body from overheating.”

Where is India on wet bulb temperature limits

Researchers from Columbia University in New York have found that hotspots on “East Coast India” and “North West India” are within 99.9% the highest wet bulb temperature (with a low of 31 degrees C) based on weather data collected from 1979 to 2017, according to a Wire report.

More generally, at least one study found that maximum wet bulb temperatures in parts of Central America, North Africa, the Middle East, northwest and southeast India and Southeast Asia have already approached or exceeded the 35°C threshold, contrary to our belief in 2010 that such temperatures were still a long way off.

The concept involves a deeper response to heat waves and its disturbances

The general limit of heat we should live within is a wet bulb temperature of 35°C, which is a measure of both the temperature and the humidity of the air. Beyond that, the body struggles to cool down.

Many communities in northern Mali, for example, have to adapt to a three-month rainy season, from July to September. Temperatures reach 50°C the rest of the year. The ramifications have been disastrous, affecting human health, agriculture and cattle production. Younger generations have no choice but to flee as they are unable to survive under these circumstances, according to a Reuters report.

Extreme heat can be hazardous to health. Heat stress causes the body to redirect blood flow to the skin and produce sweat, which cools the body. These fluctuations in blood flow put more strain on the heart, making it work harder. More sweating can promote dehydration, which reduces blood volume, puts extra pressure on the heart, and damages organs like the kidneys.

But excessive heat has received less attention than other climate hazards like floods and drought, the report says.

The 26th Conference of the Parties to the United Nations Framework Convention on Climate Change (COP26) provides an opportunity to take a closer look at the health implications of excessive heat in African countries and abroad. Particular attention should be given to how vulnerable groups such as women, newborns and the poor could be helped to manage or mitigate these impacts.

This is a frightening reality for many people

People will be affected in a variety of ways as temperatures rise.

Heat waves, which are defined as several days of unusually hot weather accompanied by high humidity, increase the risk of death from heatstroke. When the body is unable to regulate its temperature, it quickly rises to 40°C or more, causing damage to internal organs.

It also indicates that people with specific diseases, such as kidney or respiratory problems, are more likely to die, the Reuters report states.

Infectious diseases such as malaria and dengue fever will spread faster when temperatures rise. Indeed, more places will be ideal for vectors, such as malaria-carrying mosquitoes.

The drought will worsen as the temperature rises, leading to crop losses and livestock mortality. This will result in undernutrition and malnutrition, especially in children, with higher or worse rates of stunting. Malnutrition is expected to increase significantly in sub-Saharan Africa, according to projections based on climate change. For example, by 2100, the prevalence of wasting is estimated to have increased by 37% in West Africa and 25% in Central and East Africa.

With contributions from Reuters

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