The study titled 'Identifying the climate zones shifts of Indian meteorological subdivisions: insights from historical records' was made public on Friday. (File photo)Large parts of North India have turned hotter and drier over the last seven decades, while peninsular India has become wetter, according to a new study published in the India Meteorological Department’s (IMD) peer-reviewed journal Mausam.The study titled ‘Identifying the climate zones shifts of Indian meteorological subdivisions: insights from historical records’ was made public on Friday.It redraws India’s climate map using IMD data for successive 30-year climatological periods from 1951-1980 to 1991-2020.The analysis focused on four major climate zones — hot semi-arid (hot with low rainfall), tropical savannah (warm round the year with a long dry season), tropical monsoon (wettest with heavy seasonal rain) and temperate (hot summers and mild, dry winters).In Northwest India, the study found a sharp expansion of the hot semi-arid zone – from about 25 per cent of the region’s area during 1951-1980 to nearly 33 per cent during 1991-2020.Must Read | India’s east coast may soon see Arnab, the year’s first cycloneAt the same time, the temperate zone shrank from about a quarter to less than a fifth, indicating that an area equivalent to 7 per cent of the region has moved into the drier category due to rising temperatures and declining rainfall.Crucially, the dry zone that earlier ended around western Uttar Pradesh has now pushed eastwards into eastern UP, the study notes.Peninsular India showed the opposite trend.Story continues below this adThe hot semi-arid zone there shrank from around 30 per cent to 16 per cent, with most of that area shifting into the tropical savannah zone, which now covers three-fourths of the peninsula.Lead author Ananya Karmakar, scientist at IMD Pune, said the northward shift needs close monitoring for agriculture.“When we compared India’s climate map decade by decade from 1951 to 2020, the clearest change was in the north, where the hot, dry zone has pushed east into Uttar Pradesh, and because this is one of the country’s most important farming regions, the timing of sowing and harvesting there needs to be watched closely,” she said.