India may have seen a number of record-breaking warm years in the recent decades, but there has been no let-up in the extreme cold waves in the country despite global warming, an IITM study has indicated.
The analysis, led by Indian Institute of Tropical Meteorology (IITM) scientists Raju Mandal and Susmitha Joseph, took into account the number of cold wave events in the last seven decades, 1951–2022, and found that more cold wave days are occurring in the recent decades than in the previous ones.
“In the recent decade, more cold wave days have been observed across the central and eastern parts of the core cold wave zone in India. In the zone are east and west Madhya Pradesh, Jharkhand, Vidarbha, Marathwada, Uttar Pradesh, Bihar and some areas of northwest India such as Chhattisgarh, Haryana, Chandigarh and Delhi. Over the central and eastern parts, the average number of cold wave days has increased by more than five days per decade, and even by over 15 days per decade, in some places during the 2011-2021 period,” Mandal told TOI.
On an average, he said, the central and eastern parts of the core cold wave zone in India used to record 2-5 cold wave days per 10 years during most decades from 1951-2011. This rose to nearly 5-15 days in the last decade ending 2021.
“It could hence be concluded that the cold wave events tend to occur more over the central and eastern parts of this cold wave zone in recent times — except extreme north (for example Jammu & Kashmir) where no changes are seen over the decades. The data also showed that in parts of Haryana, Chandigarh and Delhi, cold wave days have increased to 5-10 per decade during the last 20-year period, as against an average of 2-5 in the previous decades,” Mandal said.
The study found that the longest cold waves (almost 61%) that occurred during the last eight decades were associated with La Nina conditions in the equatorial Pacific Ocean. Mandal said, “We wanted to understand through the study if there can be a reduction in cold wave events amidst a global warming scenario…”
The analysis, led by Indian Institute of Tropical Meteorology (IITM) scientists Raju Mandal and Susmitha Joseph, took into account the number of cold wave events in the last seven decades, 1951–2022, and found that more cold wave days are occurring in the recent decades than in the previous ones.
“In the recent decade, more cold wave days have been observed across the central and eastern parts of the core cold wave zone in India. In the zone are east and west Madhya Pradesh, Jharkhand, Vidarbha, Marathwada, Uttar Pradesh, Bihar and some areas of northwest India such as Chhattisgarh, Haryana, Chandigarh and Delhi. Over the central and eastern parts, the average number of cold wave days has increased by more than five days per decade, and even by over 15 days per decade, in some places during the 2011-2021 period,” Mandal told TOI.
On an average, he said, the central and eastern parts of the core cold wave zone in India used to record 2-5 cold wave days per 10 years during most decades from 1951-2011. This rose to nearly 5-15 days in the last decade ending 2021.
“It could hence be concluded that the cold wave events tend to occur more over the central and eastern parts of this cold wave zone in recent times — except extreme north (for example Jammu & Kashmir) where no changes are seen over the decades. The data also showed that in parts of Haryana, Chandigarh and Delhi, cold wave days have increased to 5-10 per decade during the last 20-year period, as against an average of 2-5 in the previous decades,” Mandal said.
The study found that the longest cold waves (almost 61%) that occurred during the last eight decades were associated with La Nina conditions in the equatorial Pacific Ocean. Mandal said, “We wanted to understand through the study if there can be a reduction in cold wave events amidst a global warming scenario…”
