Table 3.
Potential solutions for addressing water scarcity of large cities*.
| City | Country | Feasibility of potential solutions | No solutions feasible | ||||||
|---|---|---|---|---|---|---|---|---|---|
| SSP1&RCP2.6a | Desalination of sea water | Groundwater exploitation | Reservoir construction | Interbasin water transfer | Domestic virtual water trade | International water transfer/virtual water trade | |||
| Delhi | India | ○ | ○ | ○ | ○ | ○ | ○ | ○ | ∎ |
| Shanghai | China | ○ | ● | ○ | ● | ● | ● | ● | |
| Mexico City | Mexico | ○ | ○ | ○ | ● | ● | ● | ● | |
| Sao Paulo | Brazil | ● | ● | ● | ● | ● | ● | ● | |
| Mumbai | India | ● | ● | ● | ● | ○ | ○ | ○ | |
| Cairo | Egypt | ○ | ○ | ○ | ● | ● | ● | ○ | |
| Beijing | China | ○ | ○ | ○ | ○ | ● | ● | ● | |
| New York | United States | ● | ● | ● | ● | ● | ● | ● | |
| Dhaka | Bangladesh | ● | ● | ○ | ○ | ● | ● | ○ | |
| Karachi | Pakistan | ○ | ● | ● | ○ | ○ | ○ | ○ | |
| Istanbul | Turkey | ○ | ● | ● | ● | ● | ● | ● | |
| Manila | Philippines | ○ | ● | ● | ● | ● | ● | ○ | |
| Tianjin | China | ○ | ● | ○ | ○ | ● | ● | ● | |
| Los Angeles | United States | ○ | ● | ● | ○ | ● | ● | ● | |
| Moscow | Russia | ○ | ○ | ● | ○ | ● | ● | ● | |
| Lahore | Pakistan | ○ | ○ | ○ | ○ | ○ | ○ | ○ | ∎ |
| Bangalore | India | ○ | ○ | ● | ○ | ○ | ○ | ○ | |
| Jakarta | Indonesia | ● | ● | ● | ● | ● | ● | ○ | |
| Lima | Peru | ○ | ● | ● | ● | ● | ● | ● | |
| Number of megacitiesb | 5 (26.3%) | 12 (63.2%) | 11 (57.9%) | 10 (52.6%) | 14 (73.7%) | 14 (73.7%) | 10 (52.6%) | 2 (10.5%) | |
| Number of large citiesb | 68 (23.3%) | 146 (50.0%) | 192 (65.8%) | 151 (51.7%) | 200 (68.5%) | 208 (71.2%) | 190 (65.1%) | 16 (5.5%) | |
*Cities with a population >10 million in 2016, which face water scarcity in 2050 under at least one scenario, were listed (sort by population from largest to smallest). Please refer to Supplementary Table 5 for all large cities. The black dots denote that the solution is applicable and probably can solve the issue, the white dots denote that the solution is inapplicable or cannot solve the issue, the black square denote that all the listed solutions are inapplicable or cannot solve the issue.
aIncluding improvement of water-use efficiency, limitation of population growth, and mitigation of climate change.
bTotal number of water-scarce megacities/large cities, which could adopt the corresponding solution to solve water scarcity issue, was listed outside parentheses while the percentage of these cities to all water-scarce megacities/large cities was provided within parentheses.
Cities with a population >10 million in 2016, which face water scarcity in 2050 under at least one scenario, were listed (sort by population from largest to smallest)*. Please refer to Supplementary Table 5 for all large cities.