Enhanced Spatial Dry–Wet Contrast in the Future of the Qinghai–Tibet Plateau

Abstract

The geographical uniqueness of the Qinghai–Tibet Plateau (QTP) determines its significance as ‘Asia's Water Tower’. It is expected that climate change in this area will cause extreme weather occurrences, stress water resources and increase the vulnerability of ecosystems in the future. However, the precise quantitative impact of climate change on the QTP remains uncertain. In this study, using coupled model intercomparison project (CMIP) phase 6 multi-model data and a distributed time-variant gain hydrological model (DTVGM), we examined the spatiotemporal attributes of climate and hydrology across the QTP under various socioeconomic progress trajectories and greenhouse gas emission scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5). Over the next 80 years, an overall warming trend was observed on the QTP, accompanied by a decrease in annual total water resources. The drier the arid regions, the wetter are the humid regions on the future QTP. Runoff will decrease by 74.92% in the region, and evaporation will increase by 84.93% from 2020 to 2099. In SSP5-8.5, the precipitation change rate was −6.22 mm/10a, and the runoff change rate was −8.84 mm/10a. After a year of abrupt precipitation change (2052–2064), the decrease in runoff became significantly faster. The total runoff was approximately 58.00% of the surface runoff. Unlike the runoff trend, evaporation displayed a fluctuating upward pattern, with an average change rate of 2.78 mm/10a. Spatially, the variations in dry–wet conditions became more evident, showing a substantial decrease in runoff and a noteworthy increase in evaporation on the northeastern plateau. In the southeastern region of the Yarlung Tsangpo River Basin, the precipitation and runoff increase rates were notably higher than those in other regions. Moreover, there was a significant surge in runoff in areas adjacent to the glaciers. In conclusion, this study offers valuable insights into decision-making concerning future developmental trajectories in the region.