Divergent Changes of Water Supply and Demand on the Tibetan Plateau over the Last 30 Years

Water resources are closely linked to contemporary societal development, particularly crucial for the “Asian Water Tower” Tibetan Plateau. This study investigated water supply at various scales on the Tibetan Plateau and assessed supply-demand risks by combining water demand. The results indicate: (1) 2005 was a turning point, with different trends observed before and after 2005 at both the basin and 1 km2 raster scales. (2) The demand for water on the Tibetan Plateau has exhibited an east-high-west-low distribution pattern over the past 30 years, with the increased areas mainly concentrated in the east. In terms of water supply and demand, the proportion of areas facing water supply shortages on the Tibetan Plateau in 2020 increased by 5.59% compared to 1990. (3) Low-risk areas occupied most of the Tibetan Plateau. Compared to the period from 1990 to 1995, high-risk areas on the Tibetan Plateau increased from 2015 to 2020, indicating an overall rise in supply-demand risk. The research findings can provide theoretical support for regional water resource sustainable management and planning.