Impacts of changes in climate, cryosphere, and vegetation on freshwater supply in the southeastern Tibetan Plateau

Cryosphere degradation and vegetation dynamics due to climate change on the Tibetan Plateau profoundly impact runoff and water security downstream, yet their contributions remain largely unquantified. Here, we quantify the contributions of these cryospheric factors to runoff dynamics in southeastern Tibetan Plateau basins using state-of-the-art attribution methods. Results show runoff increased by 14 %–83 % from the period 1982–1995 to the period 1996–2010 in the upper Brahmaputra, Salween, and Yangtze basins, respectively. Precipitation increase dominates the runoff increase in the upper Salween basin. In contrast, the accelerating melt of glaciers and ice-rich permafrost plays a prominent role in the runoff increases in the upper Brahmaputra and Yangtze basins. Vegetation greening enhances evapotranspiration, partly counteracting the runoff increases in these basins. Despite the increase in the runoff of these large rivers, the downstream water availability per capita decreases after 1995 due to population growth. This study provides new insights into the interactions of climate, cryosphere, and vegetation on water availability in the Tibetan Plateau and supports forward-looking local water management.