Various transboundary river basins are facing increased pressure on water resources in near future. However, little is known about the future drivers globally, namely changes in natural local runoff and natural inflows from upstream parts of a basin, as well as local and upstream water consumption.
In this study, authors use an ensemble of four global hydrological models forced by five global climate models and the latest greenhouse‐gas concentration (RCP) and socio‐economic pathway (SSP) scenarios to assess the impact of these drivers on transboundary water stress in the past and future.
The research's results show that population under water stress is expected to increase by 50% under a low population growth and emissions scenario (SSP1‐RCP2.6) and double under a high population growth and emission scenario (SSP3‐RCP6.0), compared to the year 2010.
The key points of this paper, are:
- Water stress will mostly intensify in areas already under stress in all future scenarios for most transboundary river basins;
- Changes in water stress are dominated by local water consumption - managing local demand is thus a key strategy to alleviate future stress;
- Less natural runoff or increased water consumption in upstream areas is the dominant driver of changes in downstream net water availability.