Climate change vs. socio-economic development: understanding the future South Asian water gap
Climate change vs. socio-economic development: understanding the future South Asian water gap
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DOI：
10.5194/hess-22-6297-2018
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发表时间：
2018-12
影响因子：
6.3
通讯作者：
R. Wijngaard;H. Biemans;A. Lutz;A. Shrestha;P. Wester;W. Immerzeel
中科院分区：
文献类型：
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作者：
R. Wijngaard;H. Biemans;A. Lutz;A. Shrestha;P. Wester;W. Immerzeel
抽象。印度河、恒河和雅鲁藏布江流域为大约9亿人提供了用于农业、家庭和工业的水资源。这些河流流域被标记为“气候变化热点”，预计气候变化将影响季风动态和冰雪融水量，从而影响可用水量。与此同时，人口的迅速和持续增长以及强劲的经济发展可能会导致对水的需求迅速增加。由于缺乏对这些未来趋势的量化，因此很难确定未来南亚水资源缺口将如何发展。为此，我们评估的综合影响，气候变化和社会经济发展的未来“蓝色”水的差距在IGB，直到世纪结束。我们采用耦合建模方法，包括分布式cryosphere水文模型SPHY，它模拟当前和未来的上游供水，和水文和作物生产模型LPJmL，它模拟当前和未来的下游水的供应和需求。我们迫使耦合模型与合奏的8个代表性的降尺度的大气环流模型（GCM），从RCP4.5和RCP8.5的情况下，和一组土地利用和社会经济的情况下，是一致的共享的社会经济途径（SSP）标记情景1和3。模拟输出用于分析水的可用性，供应，需求和差距的变化。结果表明，增加地表水的可用性接近21世纪世纪，这主要是由于季风降水的增加。然而，尽管地表水供应量增加，但强劲的社会经济发展和相关的水需求增加可能会导致世纪水缺口的扩大。这表明，社会经济发展是未来南亚水资源缺口演变的主要驱动力。未来环境流量的侵入可能会受到限制，在季风季节有持续的环境流量需求，在印度河和恒河流域的低流量季节没有满足环境流量需求。
Abstract. The Indus, Ganges, and Brahmaputra (IGB) river basins provide about 900 million people with water resources used for agricultural, domestic, and industrial purposes. These river basins are marked as “climate change hotspots”, where climate change is expected to affect monsoon dynamics and the amount of meltwater from snow and ice, and thus the amount of water available. Simultaneously, rapid and continuous population growth as well as strong economic development will likely result in a rapid increase in water demand. Since quantification of these future trends is missing, it is rather uncertain how the future South Asian water gap will develop. To this end, we assess the combined impacts of climate change and socio-economic development on the future “blue” water gap in the IGB until the end of the 21st century. We apply a coupled modelling approach consisting of the distributed cryospheric–hydrological model SPHY, which simulates current and future upstream water supply, and the hydrology and crop production model LPJmL, which simulates current and future downstream water supply and demand. We force the coupled models with an ensemble of eight representative downscaled general circulation models (GCMs) that are selected from the RCP4.5 and RCP8.5 scenarios, and a set of land use and socio-economic scenarios that are consistent with the shared socio-economic pathway (SSP) marker scenarios 1 and 3. The simulation outputs are used to analyse changes in the water availability, supply, demand, and gap. The outcomes show an increase in surface water availability towards the end of the 21st century, which can mainly be attributed to increases in monsoon precipitation. However, despite the increase in surface water availability, the strong socio-economic development and associated increase in water demand will likely lead to an increase in the water gap during the 21st century. This indicates that socio-economic development is the key driver in the evolution of the future South Asian water gap. The transgression of future environmental flows will likely be limited, with sustained environmental flow requirements during the monsoon season and unmet environmental flow requirements during the low-flow season in the Indus and Ganges river basins.