Projected Climate Extremes over Agro-climatic Zones of Ganga River Basin under 1.5, 2 and 3-degree Global Warming Levels

Abstract

Abstract In the present study, we have evaluated the extreme precipitation and temperature indices over the 10 agro-climatic zones falling under Ganga River basin (GRB)utilizing a high resolution daily gridded temperature and precipitation multi-model ensembled CMIP6 dataset (0.25°x0.25°) under global warming levels of 1.5°C, 2°C, and 3°C.We found that annual daily minimum temperature(TNN) showing higher rise of about 67% than maximum temperature (TXX)of 48%in GRB. The basin also experiences a greater increase in the frequency of warm nights (TN90P) of about 67.71% compared to warm days (TX90P) of 29.1% for 3°C global warming level.Along with extreme indices, population exposed due to the impact of the extreme maximum temperature has also been analysed for progressive warming levels. Population exposure to extreme temperature event (TXX) has been analysed with 20-year return period using GEV distribution method. The study concludes that exposed population to extreme temperature event experienced an increase from 46.99–52.16% for whole Ganga Basin. Consecutive Dry Days (CDD) and Consecutive Wet Days (CWD) both show a significant increasing trend, but CWD has significant increase in majority of the zones, while CDD show significant decreasing trend for some of the zones for three warming levels periods.Extreme climate indices help to understand the frequency and intensity of the extreme weather events such as heavy rainfall, droughts, heatwaves etc. to develop early warning systems and adaptation strategies to mitigate such events.