Contrasting Fate of Western Third Pole's Water Resources Under 21st Century Climate Change

Seasonal melting of glaciers and snow from the western Third Pole (TP) plays important role in sustaining water supplies downstream. However, future availability region, even today's runoff regime, are both hotly debated inadequately quantified. Here, we characterize contemporary flow regimes systematically assess evolution total availability, seasonal shifts, dry wet discharge extremes four most meltwater-dominated basins TP, by using a process-based, well-established glacier-hydrology model, well-constrained historical reference climate data, ensemble 22 global models with an advanced statistical downscaling bias correction technique. We show that these face sharply diverging futures under 21st century change. In RCP scenarios 4.5 8.5, increased precipitation glacier Upper Indus Yarkant more than compensate for decreased winter accumulation, boosting annual summer through end century. contrast, Amu Syr Darya will become reliant on rainfall as ice decline. river-flows, already low, fall 16%–30% end-of-century, striking increases peak flood (by >60%), drought duration >1 month) intensity factor 4.6) compound considerable water-sharing challenges this major transboundary river.