North India getting hotter, drier, South wetter: A study of 70-year climate trends uncovers worrying climate shift

India’s climate zones are not shifting uniformly. The North West and North East homogeneous regions have moved toward drier conditions. Much of peninsular India has moved toward a wetter climate. This matters because climate zones influence farming, water availability, and local livelihoods.

The clearest exception is interior Maharashtra. Marathwada and west Vidarbha were mostly in the tropical savannah zone, which is warm year-round with a long dry season. By 1991–2020, they had moved into the hot semi-arid zone. The researchers linked this change mainly to rising daytime and night-time temperatures.

Along the southern coast, the tropical monsoon zone has spread across Konkan, Goa, coastal Karnataka, and Kerala. Rainfall has generally increased over southern India but declined across the northern plains. The study connects northern drying partly to rising temperatures, falling rainfall, and the negative phase of the Victoria Mode.

A climate zone groups places with similar long-term temperature and rainfall patterns. These patterns help describe the conditions people, crops, and ecosystems experience over many years. The study used climate-zone categories to track how India’s regional climate has changed.

The article describes tropical savannah as warm throughout the year with a long dry season. A hot semi-arid zone is hot and receives low rainfall. Temperate zones are identified through their temperature and rainfall patterns; some areas shifted from temperate to arid steppe, while others moved from hot tropical Savannah to temperate, hot-summer conditions.

These categories can change when average heat or rainfall changes over decades. Interior Maharashtra’s move from tropical savannah to hot semi-arid conditions was mainly linked to rising daytime and night-time temperatures. The study therefore treats climate zones as measurable patterns, not fixed labels.

The study measured climate-zone shifts across broad Indian meteorological regions. In both the North West and North East homogeneous regions, nearly 7% of the area transformed toward a drier climate zone during the historical period examined. The researchers linked these changes to increasing temperatures and decreasing rainfall.

Peninsular India showed the opposite pattern. About 15% of that homogeneous region shifted from hot arid steppe to tropical savannah, a wetter zone. The study attributed this change mainly to increasing rainfall in more recent periods. This broad regional result excludes the Central Deccan Plateau around Vidarbha and Marathwada, which became hotter and drier.

The figures describe area that changed climate classification, not the percentage change in rainfall or temperature. They show that the direction of change differs across India. Northern regions generally dried, southern areas generally became wetter, and interior Maharashtra followed the drier trend.

Interior Maharashtra and southern India are experiencing different combinations of temperature and rainfall change. Marathwada and west Vidarbha moved from tropical savannah to hot semi-arid conditions by 1991–2020. This shift matters because both regions already face drought-related pressure and farmer suicides.

The study’s lead author attributed Maharashtra’s change mainly to rising daytime and night-time temperatures. In contrast, rainfall increased across much of southern India in recent epochs. The wetter trend helped parts of peninsular India move from hot arid steppe toward tropical savannah. Along the coast, the wet tropical monsoon zone also spread farther across several southern areas.

Maharashtra’s interior and coastline therefore changed in opposite directions. The article connects northern and interior drying with higher temperatures and reduced rainfall, while southern wetting is mainly associated with increased rainfall. These regional contrasts show why India’s climate shift cannot be described with one national pattern.

Climate zones provide conditions that agriculture, water systems, and communities have adapted to over time. If tropical savannah and temperate zones continue shrinking, areas may face unfamiliar combinations of heat and rainfall. That could make food production and water planning more difficult.

The study specifically warns about risks to food security, water resources, and regional livelihoods. A hotter, drier zone can increase pressure on farming and water supplies, especially in places already affected by drought. The article also says the disappearance of these climate zones could create problems related to local population displacement.

These risks matter for future socioeconomic development. The researchers call for large-scale climate variability to be included in long-term agricultural planning and climate-adaptation strategies. Their findings suggest that food and water policies should account for regional differences, including wetter southern areas and increasingly dry northern and interior regions.

The researchers detected shifts by analysing historical meteorological observations, along with proxy records and historical accounts. They redrew India’s climate map for successive 30-year periods, called epochs, from 1951–1980 through 1991–2020. The maps showed how regional temperature and rainfall patterns changed over time.

The study compared periods such as 1951–1980, 1961–1990, and 1991–2020 rather than relying on single years. It found, for example, that interior Maharashtra moved from mostly tropical savannah into the hot semi-arid zone by 1991–2020. It also identified expanding wet conditions along parts of the southern coast.

Thirty-year periods are the standard span used to measure climate, according to the article. A single year can be unusually wet, dry, hot, or cool. Longer periods reveal persistent averages and trends instead of short-term fluctuations. That makes them more suitable for identifying genuine climate-zone shifts.

Weather is what the atmosphere does over a short period, such as a day, week, or season. Climate is the longer-term pattern of conditions in a place. The study examined climate because it focused on average temperature and rainfall across standard 30-year periods, rather than isolated events.

Climate zones depend on those long-term measurements. If temperatures rise while rainfall declines, an area can move toward a drier classification. That pattern occurred in the North West and North East, where nearly 7% of each region shifted toward drier zones. Interior Maharashtra also became hotter and semi-arid as daytime and night-time temperatures increased.

The reverse can happen when rainfall rises over many years. About 15% of Peninsular India shifted from hot arid steppe toward tropical savannah because rainfall increased in recent epochs. These changes show why long-term averages alter the climate zone where people live, work, and farm.