Unsustainable Water Systems in High Mountain Asia Threaten Millions with Water Stress Downstream

Unsustainable Water Systems in High Mountain Asia Threaten Millions with Water Stress Downstream

Unsustainable Water Systems- Water scarcity in the High Mountain Asia (HMA) region surrounding the Tibetan Plateau (TP) has become a major issue in recent years, as this region supplies water to millions of people who depend on it for their basic needs. Unfortunately, the causes behind these changes in terrestrial water storage (TWS) of this region remain poorly understood.

Unsustainable Water Systems in High Mountain Asia Threaten Millions with Water Stress Downstream
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A recent study seeks to provide insight on this matter by using a Lagrangian particle dispersion model and satellite observations to understand the causes behind trends in TWS over the TP. They discovered that an absence of precipitation minus evaporation (PME) carried by westerlies from southeast North Atlantic was responsible for an approximate 1 Gt decrease in monthly TWS over southern TP from 2003-2016.

The study also revealed that HMA blocks the propagation of the PME deficit into central Texas, leading to an increase in monthly TWS of about 0.5 Gt. However, warming-induced snow and glacial melt as well as drying-induced TWS depletion within HMA have weakened this blocking effect, leading to a persistent northward expansion of TP’s TWS deficit since 2009.

Studies comparing two emissions scenarios indicate that by the end of the twenty-first century, up to 84% (for scenario SSP245) and 97% (for scenario SSP585) of TP could experience TWS deficits. This trend towards unsustainable water systems in HMA could further exacerbate downstream water stress.

The study emphasizes the need for sustainable water management practices in the region to guarantee water resources are utilized efficiently and effectively. Its findings could inform policy decisions and help develop strategies to mitigate water scarcity impacts throughout HMA region.

Finally, this study indicates that water resources sustainability in High Mountain Asia (HMA) surrounding the Tibetan Plateau (TP) is facing challenges due to heterogeneous trends observed in terrestrial water storage (TWS) over this plateau.

This study attributes the monthly decrease in Southern Tropical Pacific (TWS) temperature from 2003-2016 to westerlies-caused deficits in precipitation minus evaporation (PME) from the southeast North Atlantic. Research further reveals that HMA blocks the propagation of PME deficit into the central TPS, leading to an increase in monthly TWS.

However, warming-induced snow and glacial melt, as well as drying-induced TWS depletion in HMA have weaken the blocking of HMA’s mountains, leading to persistent northward expansion of TP’s TWS deficit since 2009.

According to future projections under two emission scenarios, much of the Tropical Plain could experience TWS deficits by the end of the twenty-first century, potentially leading to unsustainable water systems and increasing downstream water stress.

Thus, sustainable water management policies need to be established in HMA in order to guarantee access to resources for millions who rely on its water for their livelihoods.

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