J Arid Land https://doi.org/10.1007/s40333-022-0081-1 Science Press Springer-Verlag Implications of future climate change on crop and irrigation water requirements in a semi-arid river basin using CMIP6 GCMs Kunal KARAN 1 , Dharmaveer SINGH 2* , Pushpendra K SINGH 3* , Birendra BHARATI 1 , Tarun P SINGH 2 , Ronny BERNDTSSON 4 1 Department of Water Engineering and Management, Central University of Jharkhand, Brambe, Ranchi 835205, India; 2 Symbiosis Institute of Geo-informatics, Symbiosis International (Deemed University), Pune 411016, India; 3 Water Resources Systems Division, National Institute of Hydrology, Roorkee 247667, India; 4 Division of Water Resources Engineering & Centre for Advanced Middle Eastern Studies, Lund University, Lund Box 117, 22100, Sweden Abstract: Agriculture faces risks due to increasing stress from climate change, particularly in semi-arid regions. Lack of understanding of crop water requirement (CWR) and irrigation water requirement (IWR) in a changing climate may result in crop failure and socioeconomic problems that can become detrimental to agriculture-based economies in emerging nations worldwide. Previous research in CWR and IWR has largely focused on large river basins and scenarios from the Coupled Model Intercomparison Project Phase 3 (CMIP3) and Coupled Model Intercomparison Project Phase 5 (CMIP5) to account for the impacts of climate change on crops. Smaller basins, however, are more susceptible to regional climate change, with more significant impacts on crops. This study estimates CWRs and IWRs for five crops (sugarcane, wheat, cotton, sorghum, and soybean) in the Pravara River Basin (area of 6537 km 2 ) of India using outputs from the most recent Coupled Model Intercomparison Project Phase 6 (CMIP6) General Circulation Models (GCMs) under Shared Socio-economic Pathway (SSP)245 and SSP585 scenarios. An increase in mean annual rainfall is projected under both scenarios in the 2050s and 2080s using ten selected CMIP6 GCMs. CWRs for all crops may decline in almost all of the CMIP6 GCMs in the 2050s and 2080s (with the exceptions of ACCESS-CM-2 and ACCESS-ESM-1.5) under SSP245 and SSP585 scenarios. The availability of increasing soil moisture in the root zone due to increasing rainfall and a decrease in the projected maximum temperature may be responsible for this decline in CWR. Similarly, except for soybean and cotton, the projected IWRs for all other three crops under SSP245 and SSP585 scenarios show a decrease or a small increase in the 2050s and 2080s in most CMIP6 GCMs. These findings are important for agricultural researchers and water resource managers to implement long-term crop planning techniques and to reduce the negative impacts of climate change and associated rainfall variability to avert crop failure and agricultural losses. Keywords: climate change; crop water requirement; irrigation water requirement; CMIP6 GCMs; emission scenario; Pravara River Basin Citation: Kunal KARAN, Dharmaveer SINGH, Puspendra K SINGH, Birendra BHARATI, Tarun P SINGH, Ronny BERNDTSSON. 2022. Implications of future climate change on crop and irrigation water requirements in a semi-arid river basin using CMIP6 GCMs. Journal of Arid Land, https://doi.org/10.1007/s40333-022-0081-1. ∗ Corresponding authors: Dharmaveer SINGH (E-mail: veermnnit@gmail.com); Puspendra K SINGH (E-mail: pushpendras123@ gmail.com) Received 2022-07-27; revised 2022-09-10; accepted 2022-09-21 © Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Science Press and Springer-Verlag GmbH Germany, part of Springer Nature 2022 http://jal.xjegi.com; www.springer.com/40333