Reducing water stress worldwide

IIASA researchers have identified six water management strategies that can help reduce water stress. Implementing all six strategies, which include increased water recycling and improved irrigation techniques, would reduce the population living with water stress by 12% by 2050.

Water scarcity is not just a problem for the developing world [1]. In California, USA, legislators are currently proposing a US$7.5 billion emergency water plan to their voters; and the US federal officials warned residents of Arizona and Nevada in 2016 that they could face cuts in Colorado River water deliveries. Climate change, wasteful irrigation techniques and industrial and domestic demand lie at the root of the problem, and if current trends continue, water demand would more than double by the year 2050 [2][3][4]. But despite what appears to be an insurmountable problem, it is possible to turn the situation around and significantly reduce water scarcity in just over 35 years, IIASA research has found.

“Water stress” is a term used to describe a situation where more than 40% of the water from the rivers in an area is unavailable because it is already being used [5][6]. Currently, about a third of the global population is affected, and as many as half the people in the world may be coping with water stress by the end of the century, if the current pattern of water use continues [7][8]. Researchers from the IIASA Water Program and their collaborators have outlined six key strategies that they believe can be combined in different ways in different parts of the world to effectively reduce water stress.

The six strategies can be divided into either “hard-path” measures, involving building more reservoirs and increasing sea water desalination, or “soft -path” measures that focus on reducing water demand rather than increasing water supply. These latter often work via community-scale efforts and decision-making, and include improving irrigation efficiency and industrial water use. While there are some economic, cultural, and social factors that may make certain soft-path measures difficult, such as population control, in general the soft path offers a more realistic way forward in terms of reducing water stress.

There is no single silver bullet to deal with the problem around the world. However, by looking at the problem on a global scale, the researchers calculated that if four of these strategies were applied at the same time the number of people in the world who are facing water stress would stabilize rather than continue to grow, which is what will happen if we continue with business as usual. Significant reductions in the number of people suffering water stress are possible by 2050, but a strong commitment and strategic efforts are required to make this happen.

The impact of strategies for reducing global water stress. The six strategies, or water-stress wedges, collectively lead to a reduction in the population affected by water stress by 2050, despite an increasing population. For simplicity, the water-stress wedges are shown here as straight lines, although the proposed efforts are unlikely to produce such consistent and linear results. The climatic variability of precipitation is included in the colored lines, whereas the water-stress wedges are simplified straight-line projections.


[1] Gain AK, Giupponi C, & Wada Y (2016). Measuring global water security towards sustainable development goals. Environmental Research Letters 11 (12): e124015.

[2] Nasta P, Gates JB, & Wada Y (2016). Impact of climate-indicators on continental-scale potential groundwater recharge in Africa. Hydrological Processes 30 (19): 3420-3433.

[3] Wada Y, Lo MH, Yeh PJF, Reager JT, Famiglietti JS, Wu R-J, & Tseng Y-H (2016). Fate of water pumped from underground and contributions to sea-level rise. Nature Climate Change 6 (8): 777-780.

[4] van Vliet M, van Beek LPH, Eisner S, Flörke M, Wada Y, & Bierkens MFP (2016). Multi-model assessment of global hydropower and cooling water discharge potential under climate change. Global Environmental Change 40: 156-170.

[5] Pokhrel YN, Hanasaki N, Wada Y, & Kim H (2016). Recent progresses in incorporating human land-water management into global land surface models toward their integration into Earth system models. Wiley Interdisciplinary Reviews: Water 3 (4): 548-574.

[6] Wada Y, de Graaf IEM, & van Beek LPH (2016). High-resolution modeling of human and climate impacts on global water resources. Journal of Advances in Modeling Earth Systems 8 (2): 735-763.

[7] Wada Y, Flörke M, Hanasaki N, Eisner S, Fischer G, Tramberend S, Satoh Y, van Vliet M, et al. (2016). Modeling global water use for the 21st century: Water Futures and Solutions (WFaS) initiative and its approaches. Geoscientific Model Development 9: 175-222.

[8] Asoka A, Gleeson T, Wada Y, & Mishra V (2017). Relative contribution of monsoon precipitation and pumping to changes in groundwater storage in India. Nature Geoscience 10.


  • Taikan Oki, UNU Tokyo and University of Tokyo, Japan
  • Marc Bierkens, Utrecht University, the Netherlands
  • Tom Gleeson, University of Victoria, Canada
  • Richard Taylor, University College London, UK
  • Eric Wood, Princeton University, USA
  • Vimal Mishra, Indian Institute of Technology, India ‎
  • Ruishan Chen, East China Normal University, China
  • Matti Kummu, Aalto University, Finland
  • Albert Van Dijk, Australian National University, Australia
  • Martina Flörke, Kassel University, Germany
  • Carlo Giupponi, Università Ca’ Foscari, Italy