Climate change increases the instability of the water supply for hydropower stations on the Tibetan Plateau

In recent decades, global warming has had a significant impact on the streamflow across the Tibetan Plateau. As the largest tributary in the upper reaches of the Yangtze River, the Yalong river is known for its abundant hydropower resources, and the world’s largest multi-energy complementary base has been built in the Yalong River Basin. However, prudent water resource planning is limited by the lack of long-term, detailed and reliable streamflow records over the Yalong river basin. Here, we develop an October–June streamflow reconstruction for the Yalong River, based on composite tree-ring chronology of Picea likiangensis from seven sampling sites. The reconstruction goes back to 1480 CE, and accounts for 46.5% of the instrumental streamflow variance during 1962–2012. This record indicates that the Interdecadal Pacific Oscillation and the Atlantic Multi-decadal Oscillation were the major contributing factors to streamflow variations. A significant and stable correlation with temperature was found over the past few centuries on the interannual scale. Projections suggest that future climate change may lead to more frequent flood disasters in the Yalong River Basin.