'Ahmedabad faces 67.5% higher heatwave risk', Western India heating up, eastern cities cooling down: Study

Paul John / TNN / Updated: Apr 3, 2025, 07:57 IST

Text Size

Small
Medium
Large

A study finds western India, including Ahmedabad, is heating up with more intense heatwaves, while eastern cities like Patna and Varanasi cool down. The research attributes this difference to the Atlantic Nino affecting atmospheric circulation and moisture patterns over India. The changes are based on temperature data from 1961 to 2023.

'Ahmedabad faces 67.5% higher heatwave risk', Western India heating up, eastern cities cooling down: Study

A study finds western India, including Ahmedabad, is heating up with more intense heatwaves, while eastern cities like Patna and Varanasi cool down

AHMEDABAD: A new study has revealed a sharp contrast �?western India is heating up alarmingly, while parts of the east are cooling down. The research, spanning over six decades of temperature data, found that Ahmedabad and other western cities face longer, more intense heatwaves, whereas eastern counterparts like Patna and Varanasi are seeing fewer extreme heat events.

What is east-west heatwave asymmetry

Scientists link this to the Atlantic Nino, a climate pattern that shifts moisture-laden winds away from the west, allowing extreme heat to build up. With Ahmedabad's heatwave probability surging by 67.5%, researchers warn of an increasingly scorching future
The study found Ahmedabad now has a 67.5% higher probability of four-day heatwaves compared to 1961�?990, while the likelihood of six-day heatwaves has jumped 59%. In contrast, Patna has seen a 78% drop in four-day heatwaves over the same period.

Ahmedabad's average temperature during a 7-day heatwave with a 2-year return period increased from 42.5°C (1961�?990) to 42.8°C (1991�?023), while Varanasi saw a cooling trend, with similar heatwaves dropping from 44.3°C to 43.4°C.
These findings were presented in abstract "EGU25-592" for the EGU General Assembly 2025 and published in Environmental Research Letters. It utilises daily maximum temperature data from the Indian Meteorological Department spanning from 1961 to 2023.
What's behind this drastic disparity? The study, conducted by researchers from the Indian Institute of Technology (ISM) Dhanbad, IIT Bombay, EPFL Valais Wallis in Switzerland, and the International Centre for Theoretical Physics, identifies a major culprit: the Atlantic Nino.
Unlike the well-known El Nino phenomenon in the Pacific, the Atlantic Nino influences weather patterns over India by altering atmospheric circulation. The Atlantic Nino reverses the usual cross-equatorial wind flow during March-June. Normally, winds transport moisture from the northern Indian Ocean to Southeast Asia and the South China Sea, keeping northern India's humidity low.

About the Author

Paul John

Paul John is special correspondent at The Times of India, Ahmedabad and reports on urban infrastructure, RTI and taxation related issues. His enjoys doing human interest stories and going to rural areas and reporting on issues affecting people there.

End of Article