Future Transboundary Water Stress and Its Drivers Under Climate Change: A Global Study

Hafsa Ahmed Munia*, Joseph H.A. Guillaume, Yoshihide Wada, Ted Veldkamp, Vili Virkki, Matti Kummu

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review


Various transboundary river basins are facing increased pressure on water resources in near future. However, little is known ab out 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. Here we use an ensemble of four global hydrological models forced by five global climate models and the latest greenhouse-gas concentration (RCP) and socioeconomic pathway (SSP) scenarios to assess the impact of these drivers on transboundary water stress in the past and future. Our 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. As changes in water availability have a smaller effect when water is not yet scarce, changes in water stress globally are dominated by local water consumption—managing local demand is thus necessary in order to avoid future stress. Focusing then on the role of upstream changes, we identified upstream availability (i.e., less natural runoff or increased water consumption) as the dominant driver of changes in net water availability in most downstream areas. Moreover, an increased number of people will be living in areas dependent on upstream originating water in 2050. International water treaties and management will therefore have an increasingly crucial role in these hot spot regions to ensure fair management of transboundary water resources.

Original languageEnglish
Article numbere2019EF001321
Pages (from-to)1-21
Number of pages21
JournalEarth's Future
Issue number7
Early online date25 May 2020
Publication statusPublished - Jul 2020


Hafsa Munia received financial support from Maa-ja vesitekniikan tukiry and Doctoral School of Aalto University School of Engineering. Joseph Guillaume received financial support from the Academy of Finland funded WASCO project (Grant 305471) and the Emil Aaltonen Foundation funded project ?Eat-Less-Water?. In addition to these, Matti Kummu received financial support from European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (Grant Agreement 819202) and Academy of Finland funded WATVUL project (Grant 317320).

FundersFunder number
Doctoral School of Aalto University
Horizon 2020 Framework Programme819202
European Research Council
Suomen Akatemia305471
Emil Aaltosen Säätiö
Horizon 2020317320


    • climate change
    • representative concentration pathways
    • shared socioeconomic pathways
    • transboundary river
    • water stress


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