Future global urban water scarcity and potential solutions

• Published in: Nature communications 2021-08, Vol.12 (1), p.4667-11, Article 4667
• Main Authors: He, Chunyang, Liu, Zhifeng, Wu, Jianguo, Pan, Xinhao, Fang, Zihang, Li, Jingwei, Bryan, Brett A.
• Format: Article
• Language: English
• Subjects: 704/172; 706/2805; 706/2808; Cities; Climate change; Humanities and Social Sciences; Megacities; multidisciplinary; Population; Science; Science (multidisciplinary); Urban areas; Urban populations; Urbanization; Water demand; Water scarcity
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-25026-3

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. This paper quantifies global urban water scarcity in 2016 and 2050 and explores potential solutions. One third to nearly half of the global urban population is projected to face water scarcity problems.