The warmest average maximum temperature since 1901 was recorded in February 2023, according to the India Meteorological Department (IMD). It was almost 29.54 °C outside.
While February is categorised by the IMD as both a “spring” and a “winter month,” it is also obvious that there has been a progressive increase, with even low temperatures reaching new highs. The average maximum temperature was 1.73°C higher than average, and the average minimum temperature was 0.81°C higher than average.
In its most recent assessment, the IMD forecasted that these patterns would most likely persist into the summer. The majority of India’s northeast, east, centre, and northwest are expected to see “above normal” temperatures. During March and May, the majority of India is expected to suffer heatwaves, with the exception of the north-east, Jammu & Kashmir, Uttarakhand, Himachal Pradesh, Kerala, and coastal Karnataka.
A heatwave is a time when temperatures are unusually high. In India, they frequently happen from May through June, and in a few exceptional cases, they may even persist into July.
In order to classify heat waves, the India Meteorological Department (IMD) divides the nation into various temperature zones.
In India, there were 413 heatwave days between 1981 and 1990 and 600 days between 2011 and 2020, according to IMD.
This considerable rise in the number of heatwave days is attributable to the escalating effects of climate change.
Criteria for the Declaration of a Heatwave:
A heatwave is considered to have occurred when a station’s maximum temperature reaches at least:
40°C for the plains.
37 °C for coastal areas.
30°C for areas that are steep.
Increases of 5 to 6°C over the station’s usual maximum temperature, which is 40°C or lower, are considered to be heat wave conditions.
Additionally, a temperature increase of 7°C or more above average is considered a severe heat wave condition.
When the maximum average temperature is higher than 40°C, circumstances are considered to be in a heat wave when there are increases of 4 to 5°C from the station’s typical temperature. In addition, a rise of 6°C or more is considered a severe heat wave situation.
In addition, regardless of the typical maximum temperature, a heat wave is declared if the actual highest temperature remains at 45°C or greater.
The National Disaster Management Authority (NDMA) published suggestions on heatwaves in 2016 in attempt to create significant national-level policy for lessening the effects of heatwaves.
Climate change’s effects on crops:
Studies show that India is now more susceptible to heat waves as a result of climate change. According to a Lancet study, India lost 167.2 billion hours of potential work in 2021 due to an increase of 55% in heat-related mortality.
The extreme heat has had an impact on wheat yields throughout time. India produced 106.84 million tonnes of wheat in the 2021–22 crop season, down from 109.59 million tonnes in the 2020–21 crop season, due to a warmer than usual March that had an impact on the crop throughout its growth phase.
What these temperatures mean for this year’s monsoon is uncertain until March, when global forecast models are better equipped to analyse sea-surface conditions and safely extrapolate. In three of the last four years, India has seen above-average precipitation, primarily as a result of La Nina, or colder-than-normal temperatures in the Equatorial Pacific. Although it is expected that this will pass, it is not known if it will eventually develop into an El Nio and dredge moisture from India’s coastlines.
El Nio is a recurring warming of the Central-east Equatorial Pacific oceans (Warm phase off the coast of Peru). El Nio raises the surface temperatures of the equatorial Pacific.
As a result, the east-west trade winds, which blow near the equator, are diminished. El Nio causes the trade winds that begin in the Americas and go towards Asia to change into westerlies. As a result, the western Pacific provides warm water to America.
The El Nino event occurs unpredictably every 2 to 7 years; it does not follow a predictable cycle. El Nino and the Southern Oscillation both occur together. Together, they form the phenomenon known as El Nino-Southern Oscillation (ENSO).
El Nino events in India are directly linked to less monsoon rains, which leads to higher average temperatures and a drier than typical climate. Agriculture’s gross value added (GVA) is significantly impacted along with crop yield.
The research supporting the idea that heatwave intensity has increased due to “climate change” is still in flux, notwithstanding how simple it is to make this assertion. Complex interactions exist between regional climate and weather. But this ought to act as a wake-up call to improve public health systems and make them better ready to respond to issues brought on by changing climatic conditions.
Although some States have action plans and early warning systems, outreach is poor, particularly in rural India. Greater attention should be paid to supporting farmers in adapting their soil and water management practises, as well as selling newer crop varieties with earlier maturities.