Extreme Climate and Weather Events in India: A Comprehensive Analysis from CMIP6 Data and Projections under different SSP Scenarios

Abstract

This study utilises 13 data sets from the Coupled Model Intercomparison Project Phase 6 (CMIP6) to analyse extreme temperature and precipitation indices as defined by the ETCCD. The indices were classified according to heat wave, cold wave, flood, and drought. The indices have been computed for historical events spanning from 1951 to 2014, as well as for near-future events from 2015 to 2040, mid-future events from 2041 to 2070, and far-future events from 2071 to 2100. These calculations were performed using bias-corrected CMIP6 data, specifically under the Shared Socioeconomic Pathways (SSP) scenarios: SSP126, SSP245, SSP370, and SSP585. The ensemble mean indicates an increase in the average minimum and maximum temperatures, as well as an increase in average precipitation, across the Indian region. The analysis of the ensemble mean reveals a significant increase in the summer days (SU25), warm days (TX95p), tropical nights (TR20), and warm nights (TN90p) over the north-eastern region of India. Conversely, the central and northern parts of the Himalayan region of India experience an increase in the cold spell duration indicator (CDSI) and cool nights (TN10p). The northern plane region, central region, and western region are expected to experience an increase in heatwave number (HWN), frequency (HWF), duration (HWD), and amplitude (HWA). The analysis of the ensemble mean indicates that there is an observed increase in RX1DAY, RX5DAY, R10MM, R20MM, and CWD in the Western Ghats and north-eastern regions of India. Conversely, there is a decrease in CDD across the entire Indian region. The region of Central India exhibits dynamic behaviour in terms of precipitation and temperature indices under various climate change scenarios. The various scenarios of the SSP demonstrate a notable rise in the occurrence of extreme events such as floods and heatwaves in the medium and distant future. Keywords: CMIP6, Ensemble mean, Extreme temperature and precipitation indices, ETCCDI, Heat wave, Cold wave, Flood, Drought