Future changes in extreme precipitation and warm days over megacities of India and the semi-arid Tirupati district

Abstract

We study future changes in extreme precipitation and warm days over selected megacities of India and the semi-arid Tirupati district. This work synthesises projected changes in climate extremes using indices from the Expert Team on Climate Change Detection and Indices (ETCCDI). It utilises gridded rainfall and temperature data from IMD for the historical period and future projections from the NEX-GDDP-CMIP6 dataset under moderate (SSP2-4.5) and high (SSP5-8.5) warming scenarios for 2026-2100. Projections indicate a consistent increase in both mean annual precipitation and the number of heavy rainfall days across the analysed cities, with larger increases under the high-emissions scenario. Changes in consecutive wet days exhibit spatial heterogeneity, displaying complex patterns without a uniform trend across all cities. A consistent and accelerating warming trend is projected across all cities, leading to a significant increase in warm-day frequency throughout the century, particularly under the SSP5-8.5 scenario. For the Tirupati district, annual precipitation is projected to increase under both scenarios, with the southwest monsoon season showing particularly notable enhancement. Substantial warming is also projected across all seasons for Tirupati, with the pre-monsoon season expected to experience the most severe warming. These findings emphasise the critical need for tailored, region-specific adaptation strategies and highlight how future emissions pathways will significantly influence the severity of climate impacts.