The sweltering heat has begun to torment regions, with temperatures crossing the 40°C mark in several areas. The meteorological department predicts that the heat will intensify in May. A surge in temperatures above the average is expected in most parts of the country during this period.
The department also anticipates an increase in the number of heatwave days this May, especially endangering North India including Delhi.
A press release issued by the meteorological department highlighted that southern Rajasthan, western Madhya Pradesh, Vidarbha, Marathwada, and Gujarat might experience heatwaves for 8 to 11 days in May. In other areas, heatwaves could last for 5 to 7 days.
This is especially worrisome because typically, North and Central India face a maximum of three heatwave days in May. Recent trends indicate that April witnessed an alarming 15 heatwave days in parts of West Bengal and 16 days in Odisha - a record in itself.
The Escalating Heat
India's temperatures have been steadily increasing. Over the past few years, each year has successively broken heat records. According to the meteorological department, 2023 ranks as the second hottest year since 1901.
The country's temperature in 2023 averaged 0.69°C higher than normal. Previously, 2016 held the record for the highest increase at 0.71°C. It's alarming to note that the five hottest years on record have all occurred within the last 14 years: 2016, 2023, 2009, 2017, and 2010, with the temperature increments at 0.55°C, 0.54°C, and 0.53°C, respectively.
According to the Ministry of Statistics, 2022 had 190 days of heatwaves across different parts of the country. The previous year, in contrast, experienced only 29 days of heatwaves. Moreover, 2023 recorded 166 days of heatwaves.
Source: aajtak
What Qualifies as a Heatwave?
Heatwaves are defined by specific criteria. A heatwave declaration occurs when temperatures exceed 40°C in the plains, 37°C in coastal areas, and 30°C in hilly regions.
Moreover, a heatwave is announced when any region's temperature rises between 4.5°C to 6.4°C above the normal average.
Measuring Temperatures
There are two main types of thermometers used to measure temperature globally: 'Dry Bulb' and 'Wet Bulb'. The dry bulb thermometer measures air temperature, while the wet bulb is used to gauge humidity or mugginess in the air. The latter's readings are particularly significant for us.
How Much Heat Can We Withstand?
Our body's normal temperature is around 37°C, while our skin's temperature sits at 35°C. The variance in temperature is what causes us to sweat. As sweat evaporates, it takes body heat with it.
But when the wet bulb temperature reaches 35°C, it's a different story. Such temperatures can spell danger since 35°C or more creates excessive humidity, preventing sweat from evaporating. This brings about a surge in body heat, which can be fatal if persisting for over six hours.
Yet no situation has arisen where the wet bulb temperature exceeded 35°C for more than six hours. Nonetheless, areas in Iran came close in 2015, the same year when India witnessed over 2,000 deaths from the heat, the highest number of heatstroke deaths in a single year.
Scientists believe climate change is exacerbating the heat. In the coming decades, the global temperature is expected to rise by over 2.5°C, resulting in more frequent 35°C events.
As global temperatures rise rapidly due to climate change, the predicted fatalities from heatwaves are expected to quadruple by 2050 compared to the present day. In Europe alone, the summer of 2022 saw upwards of 62,000 heat-related deaths.
It's not only India—temperatures worldwide are increasing, with deaths from heat on the rise each year. A report from the Ministry of Earth Sciences on climate change warns that by 2100, India's temperature could soar by 4.4°C.
The Paris Climate Agreement of 2015 aimed to cap the rise in global temperature to 1.5°C by the year 2100. However, countries around the world, including India, are struggling with severe heat, making it challenging to meet this target by 2100.
Even with preventive measures, a report by the World Bank predicted that India's average annual temperature would still increase by 1 to 2°C by 2050. Without interventions, the increase might reach between 1.5°C to 3°C per year.
According to Germanwatch, India is the 14th most climate-vulnerable country globally. About half of India's population, roughly 600 million people, live in areas that could face serious consequences of climate change by 2050.
