Warming and wetting-driven increases in landscape instability and river sediment loads in High Mountain Asia

Abstract

High Mountain Asia, encompassing the Tibetan Plateau and the surrounding high Asian mountains, has been experiencing a warmer and wetter climate since the 1950s. The amplified climate change has resulted in rapid glacier retreat and permafrost degradation that further cause mountain landscape instability associated with frequent cascading hazards including (rock-ice) avalanches, landslides, debris flows, and outburst floods from glacial- and landslide-dammed lakes. Moreover, the mountain erodible landscapes are expanding and greater amounts of sediment are mobilized in both glacierized and permafrost basins. The river sediment loads in High Mountain Asia have been increasing at a rate of 13% per decade since the 1950s and will likely double by 2050 under an extreme climate change scenario. The climate change-driven mountain landscape instability, increases in river sediment loads and changes in seasonal sediment-transport regimes affect water quality, carbon cycle, floods, infrastructure, and livelihoods. Such findings have implications for other high mountain areas and polar regions and we call for a global assessment of the warming and wetting-driven erosion and sediment transport.