RESPONSE OF RIVERINE SEDIMENT FLUXES TO CLIMATE CHANGE IN HIGH MOUNTAIN ASIA AND ITS MARGINS

Abstract

Rivers originating in High Mountain Asia (HMA) are experiencing amplified climate change, glacier retreat, and permafrost thaw. However, the sedimentary impacts of climate change remain poorly understood. This study holistically addresses this knowledge gap by integrating all the available multi-decadal fluvial sediment flux data in HMA and its margins, examining their temporal trends, investigating and quantifying the driving factors, and assessing their downstream impacts. I find substantial increases in both annual runoff and annual sediment fluxes over the past six decades in 28 headwaters, with accelerating increases after the mid-1990s, in response to the warming and wetting climate. The total sediment flux from HMA is projected to more than double by 2050 under an extreme climate change scenario. These findings have far-reaching implications for the region’s hydropower-food-environmental security.