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. 2021 Aug 3;12(1):4667.
doi: 10.1038/s41467-021-25026-3.

Future global urban water scarcity and potential solutions

Chunyang He  1   2 , Zhifeng Liu  3   4 , Jianguo Wu  1   2   5 , Xinhao Pan  1   2 , Zihang Fang  1   2 , Jingwei Li  6 , Brett A Bryan  7
Affiliations

Future global urban water scarcity and potential solutions

Chunyang He et al. Nat Commun. .

Abstract

Urbanization and climate change are together exacerbating water scarcity-where water demand exceeds availability-for the world's cities. We quantify global urban water scarcity in 2016 and 2050 under four socioeconomic and climate change scenarios, and explored potential solutions. Here we show the global urban population facing water scarcity is projected to increase from 933 million (one third of global urban population) in 2016 to 1.693-2.373 billion people (one third to nearly half of global urban population) in 2050, with India projected to be most severely affected in terms of growth in water-scarce urban population (increase of 153-422 million people). The number of large cities exposed to water scarcity is projected to increase from 193 to 193-284, including 10-20 megacities. More than two thirds of water-scarce cities can relieve water scarcity by infrastructure investment, but the potentially significant environmental trade-offs associated with large-scale water scarcity solutions must be guarded against.

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Conflict of interest statement

The authors declare no competing interests.

Figures

Fig. 1
Fig. 1. Current urban water scarcity.
a spatial patterns of large cities in water-scarce areas (cities with population above 10 million in 2016 were labeled). b Water-scarce urban population at the global scale. c Water-scarce urban population at the national scale (10 countries with the largest values were listed). Please refer to Supplementary Data for urban water scarcity in each catchment.
Fig. 2
Fig. 2. Changes in urban water scarcity from 2016 to 2050.
a Changes in water-scarce urban population at the global scale. Bars present the simulated results using the ensemble mean of runoff from GCMs, the total values (i.e., perennial and seasonal), and percentages are labeled. Crosses (gray/black) present the simulated results (total/perennial) using runoff from each GCM. b Changes in water-scarce urban population at the national scale (10 countries with the largest values were listed). Bars present the total values simulated using the ensemble mean of runoff from GCMs. Crosses present the total values simulated using runoff from each GCM. Please refer to Supplementary Data for urban water scarcity in each catchment.
Fig. 3
Fig. 3. Changes in large cities subject to water scarcity from 2016 to 2050 under the four socio-economic and climate change scenarios.
Only the water-scarce cities are listed. Cities with a population >10 million in 2016 are labeled.
Fig. 4
Fig. 4. The effects of different factors on growth in global urban population exposed to water scarcity from 2016 to 2050.
Bars present the simulated results using the ensemble mean of runoff from GCMs, crosses present the simulated results using runoff from each GCM.
See this image and copyright information in PMC

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