Future upstream water consumption and its impact on downstream water availability in the transboundary Indus Basin

[摘要] The densely populated plains of the lower Indus Basin largelydepend on water resources originating in the mountains of the transboundaryupper Indus Basin. Recent studies have improved our understanding of thisupstream–downstream linkage and the impact of climate change. However, wateruse in the mountainous part of the Indus and its hydropolitical implicationshave been largely ignored. This study quantifies the comparative impact ofupper Indus water usage, through space and time, on downstream wateravailability under future climate change and socio-economic development.Future water consumption and relative pressure on water resources will varygreatly across seasons and between the various sub-basins of the upperIndus. During the dry season, the share of surface water required within theupper Indus is high and increasing, and in some transboundary sub-basinsfuture water requirements exceed availability during the critical wintermonths. In turn this drives spatiotemporal hotspots to emerge in the lowerIndus where seasonal water availability is reduced by over 25 % comparedto natural conditions. This will play an important, but previously unaccountedfor, compounding role in the steep decline of per capita seasonal wateravailability in the lower Indus in the future, alongside downstreampopulation growth. Increasing consumption in the upper Indus may thuslocally lead to water scarcity issues, and increasingly be a driver ofdownstream water stress during the dry season. Our quantified perspective onthe evolving upstream–downstream linkages in the transboundary Indus Basinhighlights that long-term shared water management here must account forrapid socio-economic change in the upper Indus and anticipate increasingcompetition between upstream and downstream riparian states.

[学科分类] 妇产科学