Characteristic changes in climate projections over Indus Basin using the bias corrected CMIP6 simulations

The Indus Basin is one of the most vulnerable regions due to climate change. This article presents the mean precipitation and temperature changes along with their extremes over the Indus Basin (IB). Here we used the statistically downscaled, bias-corrected, high-resolution data from the newly emerged Coupled Model Intercomparison Project Phase 6 (CMIP6) of two Shared Socioeconomic Pathways (SSP2-4.5 and SSP5-8.5) in response to global warming. The spatial variations of precipitation, maximum and minimum temperature obtained from the Multi-Model Mean (MMM) of CMIP6 models showed a good agreement with APHRODITE (precipitation) and CPC (temperature) for the base period (1995–2014) over the basin. Results suggest that the precipitation may increase as high as 40% from June to September (JJAS) and 25% from December to February (DJF) in the SSP5-8.5 scenario by the end of the century. Future temperature projections show that warming may continue over the basin. A significant warming was noticed in the SSP5-8.5 scenario than the SSP2-4.5 scenario, with a maximum increase of more than 4 °C towards the end of the twenty-first century. Analysis of spatiotemporal variations of future extreme precipitation indices viz RD, SDII, RX1DAY, RX5DAY, R10MM, R20MM except CDD are high in number over Upper Indus Basin (UIB) compared to Lower Indus Basin (LIB). Extreme temperature indices such as TXx, SU, CSU, TNn, FD, CFD, TR except for ID show an increase of 40% to more than 75% under the SSP5-8.5 scenario compared to the baseline period over the basin.