‘Asian water towers’ are not a sustainable solution to the downstream water crisis

Abstract

Quantifying climate change- and socioeconomic development-induced changes in the ‘water tower’ function is a major challenge in high-mountain Asia (HMA), especially when considering the affected downstream areas. This study applies historical monsoon-influenced rainfall patterns and the water stress index to quantify the climate change- and socioeconomic growth-induced changes in the ‘Asian water tower’ function through the middle of the 21st century by nonparametric empirical quantile mapping and empirical orthogonal function analysis. Water pressures are predicted to intensify in 25.84 ± 7.87 % of ‘water tower’ downstream watersheds. Enhancements in the ‘Asian water tower’ function are vulnerable to help stop the deterioration of downstream water pressure while increasing the water sufficiency probability by 7.97 ± 15.52 %. Water withdrawals are projected to explain 55.90 ± 21.77 % of water security in the ‘water tower’ function-affected watersheds in 2050; thus, this study calls for more effective policies and the development of technologies to reduce the water crisis in downstream HMA.