Impacts of climate change and freeze–thaw cycles on water and sediment fluxes in the headwater region of the Yangtze River, Qinghai–Tibet Plateau

•Climate change fueled substantial increases in water and sediment fluxes.•The seasonal freeze-thaw cycles changed the soil erosion patterns.•Higher-frequency rainstorm events exacerbated freeze-thaw erosion.•In the initial thaw and freezing periods, sediment fluxes substantially increased.•The extension of the thawing duration increased the sediment supply.