Published in the peer‑reviewed journal Mausam on Friday, the study—titled ‘Identifying the climate zones shifts of Indian meteorological subdivisions: insights from historical records’—uses 30‑year blocks to redraw India’s climate map. Researchers sifted through IMD data spanning 1951‑2020, a standard climate window, to track how temperature and rainfall have reshaped the country’s four main zones.
In the north‑west, the hot semi‑arid zone swelled from about a quarter of the region’s area to one‑third, while the temperate zone shrank from a quarter to less than a fifth. That means roughly 7% of the region’s land has crossed into drier, hotter territory as temperatures climb and rainfall recedes.
Peninsular India, in contrast, has shed hot semi‑arid areas, dropping from 30% to 16%, with most of that land moving into the tropical savannah zone that now blankets three‑quarters of the peninsula. The southern shift indicates a wetter trend, a reversal of the north’s drying.
Ananya Karmakar, IMD Pune’s lead author, warned that the north’s expansion could disrupt the timing of sowing and harvesting in a farming heartland. “Because this is one of the country’s most important agricultural regions, the window for crop cycles needs close scrutiny,” she said. Farmers in eastern Uttar Pradesh already report earlier onset of heat waves and reduced monsoon rains, forcing them to adjust seed varieties.
The government has slated a review of its crop‑planning guidelines for the upcoming fiscal year, and the Ministry of Agriculture has convened a technical committee to assess the study’s implications. The IMD will publish a follow‑up analysis next quarter, and an international climate conference in New Delhi is scheduled for November to discuss the findings.