HYDERABAD: Telangana’s drought-prone districts are facing a growing climate challenge as rising temperatures combine with highly variable rainfall, with Rangareddy emerging as the most vulnerable among the six districts studied over 43 years.
The study, titled “Integrated Drought Diagnostics in Telangana (1981-2023): Trend Analysis, Multi-index Assessment, Quadrant Framework, and Interpretable Machine Learning”, analysed India Meteorological Department (IMD) gridded rainfall and temperature data for Adilabad, Khammam, Mahbubnagar, Medak, Nalgonda and Rangareddy between 1981 and 2023.
The strongest signal was the rise in maximum temperatures. The analysis found statistically significant increases across most of the six districts, with estimates indicating warming of 0.03°C to 0.06°C per year. Minimum temperatures also increased in some areas, but the changes were weaker and generally not statistically significant.
May emerged as the hottest month, with maximum temperatures reaching 42-44°C across the districts. Khammam recorded the highest extreme in the dataset at 44.1°C in 1984.
Rainfall, however, did not show a uniform long-term increase or decline. Instead, substantial year-to-year variability was recorded. Rainfall coefficients of variation ranged from 22% in Khammam to more than 35% in Rangareddy, indicating much greater variability in the latter. The combination of warming and unpredictable precipitation poses a particular challenge for drought management.
Rangareddy recorded the lowest average rainfall among the six districts at 548.9 mm, compared with 927.6 mm in Khammam. Its rainfall variability was also the highest. The climate-stress analysis placed Rangareddy in the High Risk Climate Stress Zone, where low rainfall, high variability and peak maximum temperatures above 42°C converge.
The study also linked Rangareddy’s vulnerability to its geographical and soil characteristics. With an area of about 7,493 sq km, it was the smallest of the six districts studied and is characterised by red sandy, shallow soils. Its cropping intensity was estimated at around 115%, with paddy, maize and vegetables among the key crops.
Drought, however, was not restricted to Rangareddy. Multiple drought indices showed that 20-30% of years were drought-affected, particularly in Mahbubnagar and Rangareddy. Negative ZSI values also indicated recurrent below-normal rainfall anomalies.
The researchers used the Standardised Precipitation Index (SPI) to assess different dimensions of drought. SPI identified six to nine severe drought years in each district. The study found that nearly 79% of Telangana’s annual precipitation comes from the southwest monsoon. August accounted for 29.7% of rainfall, followed by July at 21.2% and September at 18.6%, highlighting the state’s dependence on monsoon fluctuations for water availability and agricultural conditions.
Using a quadrant-based framework combining rainfall magnitude, variability, extremes and temperature, the researchers divided the districts into four climate-stress categories.
