Assessing the Effect of Glacier Runoff Changes on Basin Runoff and Agricultural Production in the Indus, Amu Darya, and Tarim Interior Basins

Abstract

Climate change is leading to a substantial reduction in glacier mass, and it is anticipated that during this century, the peak water contribution of glaciers to runoff will occur in major glacierized basins around the world. Glacier runoff is a crucial source of water in mountain basins, and a decrease in its contribution can affect agricultural production. In this study, we modeled the agricultural sector's response to changes in glacier runoff in the Asian basins of Amu Darya, Tarim Interior, and Indus, using the Global Change Analysis Model, which was driven by surface runoff derived from the Xanthos hydrological model and the Open Global Glacier Model. Our findings indicate that under SSP5-8.5, there is an increase in accessible water during the Peak-Water Glacier Runoff compared to the Historical Glacier Runoff scenario. However, accessible water under SSP58.5 falls below the Historical Glacier Runoff scenario in the last decades of the 21st century. The initial increase in accessible water drives the GCAM agricultural model to increase the production of oil crops, root tubers, sugar crops, and fruits, but only temporarily until peak glacier runoff occurrence. In Pakistan, we observe the adaptive response of neighboring basins (increased production) to a reduction in crop production in the Amu Darya and Indus and vice versa. Our results support the argument that policymakers should implement a holistic long-term perspective, in which the apparent positive economic effect of the temporary increase in accessible water is balanced with the threat to intergenerational access to freshwater and ecosystem conservation.