Impacts of climate change on the glacier melt runoff from five river basins

This study assesses the impacts of climate change on river flow from highly glaciered river basins using the Soil and Water Assessment Tool (SWAT). Analyses are conducted for five river basins that are global in coverage and vary in climatic condition. These include the Narayani (Nepal), Vakhsh (central Asia), Rhone (Switzerland), Mendoza (central Andes, Argentina), and central dry Andes (Chile). The predicted future climate change by two RCP (representative concentration pathway) climate change scenarios (RCP4.5 and RCP8.5) and six CMIP5 (Coupled Model Intercomparison Project 5) models are presented. Simulations of mean annual runoff, mean monthly runoff, high (Q5) and low (Q95) monthly runoff, and flow duration curves under baseline (1979-2008) and climate change scenarios are presented. Results showed that mean annual water yield under RCP4.5 and RCP8.5 increased 17% and 40%, respectively, for Rhone, 50% and 80% for Narayani, 65% and 116% for Vakhsh, 28% and 55% for Mendoza, and 17% and 30% for Chile. For a GCM ensemble and RCP8.5, all glaciers with 100 m water equivalent will disappear by 2100 across the Rhone, Narayani, and central Chilean river basins, while in Mendoza and Vakhsh at least 41% and 2%, respectively, of the glaciers will remain.