Ramaiyanpatti tank bed near Dindigul in Tamil Nadu dried up due to a lack of rain. (File photo)
| Photo Credit: KARTHIKEYAN G
Tamil Nadu is among the more pronounced drought hotspots in India, as a new 52-year analysis has found that South Peninsular India, the region that includes Tamil Nadu, recorded the strongest long-term increase in drought-affected area among the four broad climatic regions of the country.
The study, ‘Evolution of Climate Extremes Over the Indian Subcontinent Using a Revised CEI’, published in the International Journal of Climatology, analysed daily rainfall and temperature data from 1971 to 2022 to assess changes in multiple climate extremes. The researchers developed a revised India Climate Extremes Index (IndCEI) combining seven indicators, including heat, drought, dry spells, and heavy rainfall.
The study found a strong positive trend in drought-affected areas over South Peninsular India, with the trend being the strongest among the four regions. While less than 10% of the region was affected by drought in much of the period before the 1990s, several years after 2000 saw more than 40% of the region under drought conditions. The researchers noted that severe and persistent drought conditions were particularly evident during the 2010s and early 2020s.
The study’s regional classification places Tamil Nadu within South Peninsular India. A media note accompanying the research identifies Tamil Nadu, along with Odisha and Andhra Pradesh, among the eastern coastal States where the area affected by drought increased by 20% to 30% during 2011–2021, compared to the 1980s.
The researchers used the Standardised Precipitation-Evapotranspiration Index (SPEI) to assess drought. Unlike an indicator based only on rainfall, SPEI incorporates both precipitation and potential evapotranspiration, thereby capturing the influence of increasing temperatures on water availability.
The findings also point to a growing heat burden over southern India. The area experiencing high maximum-temperature extremes has increased in South Peninsular India, particularly since the 2010s. The researchers said the increase in heat exposure could be linked to declining rainfall, urban heat-island effects, and broader climate change impacts.
The Heat Index, which combines temperature and humidity to indicate heat stress, also showed a steady increase over South Peninsular India. The study attributes the intensification partly to rising minimum temperatures and high humidity associated with the region’s proximity to the Bay of Bengal. Urbanisation and warmer sea-surface temperatures were also identified as factors that could amplify heat stress.
However, the study found that consecutive dry days did not show a significant long-term increase over South Peninsular India. The researchers recorded strong year-to-year variability, including a prominent peak in 2002, but the overall trend was nearly flat. They cautioned that the use of May–October for this indicator may have dampened the long-term trend because of the inclusion of pre- and post-monsoon months.
The researchers said the findings underline the need for region-specific adaptation, particularly drought resilience in southern India. The accompanying media note calls for a cross-sectoral response covering agriculture, water management, health, and infrastructure, alongside finer-scale monitoring to identify localised climate extremes.
The study was conducted by scientists from the National Centre for Medium Range Weather Forecasting, India Meteorological Department, and Atria University, using IMD’s 1° × 1° gridded rainfall and temperature datasets covering 1971–2022.
Published – September 26, 2026 08:32 pm IST
