CHENNAI: Tamil Nadu has emerged as one of the pronounced drought hotspots as the South Peninsular India (SPI), among the four major climatic regions in the country, recorded the strongest long-term increase in drought-affected area, according to a 52-year climate study.
The peer-reviewed study — “Evolution of Climate Extremes Over the Indian Subcontinent Using a Revised CEI”, recently published in the International Journal of Climatology — analysed daily rainfall and temperature data from 1971 to 2022. Scientists from National Centre for Medium Range Weather Forecasting (NCMRWF), India Meteorological Department, and Atria University developed a revised India Climate Extremes Index using seven indicators, including drought, heat, heavy rainfall and dry spells.
Using the Standardised Precipitation-Evaporation Index (SPEI), which considers rainfall and atmospheric water demand, the researchers found that the drought-affected area in the SPI increased after 2000, with several years recording over 40% of the region under drought.
Spatial analysis shows that drought extremes have expanded considerably in recent decades. Between 2011 and 2021, large parts of southern, central and northeastern India recorded drought frequencies exceeding 20% per decade. “The clearest drought signal in the country is over southern India, and Tamil Nadu lies within that belt; on the eastern coast we identify as one of the most pronounced drought hotspots,” said M Rajeevan, co-author of the study and former secretary of the Ministry of Earth Sciences.
Thota Mohan, lead author and a scientist at NCMRWF, said, “Across 50 years, drought over the south has intensified more than almost any other hazard we measured.”
Tamil Nadu’s rainfall history illustrates the potential severity of drought when the northeast monsoon fails. The state received only 168.3 mm of rainfall during October-December in 2016 against a normal 440 mm -- a 62% deficit. As many as 13,305 of the 16,682 revenue villages were affected by drought, and the state declared all 32 districts drought-affected.
The TN government’s latest El Niño preparedness assessment also lists drought, water scarcity and reduced reservoir inflows among the risks that need to be monitored. Historical records cited in the report show that El Niño years can produce both drought and excess rainfall in the state. During 1997, for instance, the state received 52% excess northeast monsoon rainfall, while the 2015-16 El Niño cycle was followed by severe drought of 2016.
Meanwhile, the state’s El Niño advisory committee has highlighted water stress and drought as risks extending into 2027 and called for changes in farming practices. The committee has recommended promoting water-efficient, short-duration, heat- and drought-tolerant crop varieties, while reducing water-intensive crops in vulnerable zones through targeted incentives.
