IMD study finds southern India growing wetter over seven decades
Research by India Meteorological Department scientists reveals a dramatic contraction of semi-arid zones in southern India amid long-term rainfall gains.
Southern India has turned noticeably wetter over the last seven decades as climate zones across the peninsula shifted towards higher rainfall patterns, according to a comprehensive study by the India Meteorological Department (IMD) and the Indian Institute of Tropical Meteorology (IITM), Pune.
The research, published in the IMD peer-reviewed journal MAUSAM, reveals that the proportion of peninsular India classified as hot semi-arid nearly halved between 1951 and 2020. Scientists analyzed 70 years of temperature and precipitation observations to trace a transition from semi-arid conditions into wetter tropical savannah climates, delivering crucial insights for long-term agricultural resilience.
Mapping climate shifts across regions
Using the Köppen-Geiger climate classification system, researchers evaluated shifts across meteorological subdivisions over consecutive 30-year windows. While southern states gained rainfall, parts of north-western India experienced declining precipitation and expanding semi-arid belts.
| Region | Climate Trend (1951–2020) | Key Shift Drivers |
|---|---|---|
| Peninsular India | Semi-arid zone shrank from 30% to 16% | Sustained rainfall gains; tropical savannah expansion |
| North-West India | Semi-arid zone expanded eastward | Declining rainfall extending into eastern Uttar Pradesh |
| National Overview | Warming trend across subdivisions | Rise in both daytime and night-time temperatures |
The study identified that the transition in southern India accelerated sharply during the 1981–2010 and 1991–2020 periods. Tropical savannah zones, characterized by higher rainfall coupled with a distinct dry season, now cover nearly three-quarters of peninsular India, compared to around three-fifths in the 1950s.
Strengthening agricultural planning
Lead author Ananya Karmakar of IMD Pune noted that long-term increases in rainfall provide pivotal baseline data for regional water management and cropping decisions, especially in states dependent on seasonal monsoon systems.
IMD Director-General Mrutyunjay Mohapatra confirmed that the department's seasonal weather advisories and agricultural forecasts actively incorporate these historical climate trends alongside real-time monitoring. By integrating long-term climate findings into farmer guidance and water planning, India continues to enhance farm productivity and national food security against evolving global climate patterns.
Key numbers
| What | Figure | Source |
|---|---|---|
| Hot semi-arid climate area in peninsular India | Halved from 30% to 16% | IMD and IITM Pune study published in MAUSAM |
| Tropical savannah climate coverage in peninsular India | Expanded from ~60% to ~75% | IMD and IITM Pune study published in MAUSAM |
| Historical analysis timeframe | 1951 to 2020 (70 years) | IMD and IITM Pune study published in MAUSAM |
In this story
| Name | Role in the story |
|---|---|
| India Meteorological Department | Conducted and published the long-term climate classification study. |
| Southern India | Region identified as growing wetter over seven decades. |
| Indian Institute of Tropical Meteorology | Co-authored the joint study on shifting climate zones. |
