Northwest India has been experiencing "unusual" rise in temperatures this February. An alarm was sounded across the country when the India Meteorological Department (IMD) issued an early heatwave alert in some parts of Maharashtra, Konkan and Kutch regions earlier this week. Skymet Weather said on Wednesday that a heatwave is possible in the first week of March.

But why is India seeing such an unusual rise in temperature, what will be its impact and what lies in future ahead? CNBCTV-18 spoke with Skymet Weather Services president GP Sharma to find answers.

Why is the temperature in India rising early than usual?

This is because of weak western disturbances and subsequent less rainfall. Sharma said the temperatures are mainly controlled..."over northern or the central part...by the western disturbance, which we know that they start early in the month of November, carry on for December, January and February. Then march onwards, they start shifting towards the north."

However, there were no significant western disturbances in November and December. "Whenever they are mostly inactive, there's rainfall deficiency in plains and hilly regions. The shortfall gets on accumulating and it will be reflected in terms of the temperature profile in parts of Haryana, Delhi, Rajasthan and even Madhya Pradesh."

"In January, we have seen intense snowfall because of western disturbance, but again from February, the intensity of western disturbance has reduced while the frequency has increased," Mahesh Palawat, vice president of Skymet weather, was quoted by The Print as saying.

GP Sharma further explained the role of prevailing La Niña conditions in rising temperatures. "We are going through La Niña condition for the third consecutive year (it adversely impacts the Indian monsoon)...this condition gives less than normal rainfalls...you can expect more heat...I'm worried about this as it will spill onto March." During La Niña events, trade winds are even stronger than usual, pushing more warm water toward Asia.

Meteorologist Navdeep Dahiya further adds that an anti-cyclone — clear skies and no rain — over India also added to the heat woes. "A very early and strong anti-cyclonic circulation is dominating the atmosphere over India and has already resulted in one of the earliest 40°C maximum temperatures in India," he tweeted on February 16.

What is the impact of rising temperature?

While this may not be a sign of early summer, these high temperatures can adversely affect wheat crop which is approaching the reproductive growth period — which is sensitive to temperature, the IMD says.

Sharma raised concerns saying that the early "soaring temperature above the normal" in North India will lead to some anxious moments for the farming community of the country.

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"High temperature during flowering and maturing period lead to loss of yield," the weather department said. Sharma also added that the "excess temperature for February, which will extend to March, will damage the grain filling...this will in turn affect the Rabi crops in general and wheat in particular."

"There could be an impact on other standing crops and horticulture," the IMD noted.

What in the future?

Sharma expects this condition to get prolonged year after year. "Abnormal and high impact weather events are frequented by climate change. It gets prolonged...these events would be a little more frequent... they might get prolonged in the coming years also."

When is a heatwave alert issued?

Heatwave is declared if the maximum temperature of a station reaches at least 40 degrees Celsius or more for plains and at least 30 degrees Celsius or more for hilly regions.

Advisory to farmers

Farmers are advised to check if the crop appears to be under stress and light irrigation can be provided. They are also advised to add mulch material in the space between two rows of vegetable crops for the conservation of soil moisture and to maintain the soil temperature.

(With inputs from Abhimanyu from CNBCTV18)

(Edited by : Pradeep John)

First Published:Feb 22, 2023 5:22 PM IST