Humanity’s challenge of the century: Conserving Earth’s freshwater systems
Many dryland cities like Los Angeles, Cairo and Tehran have already outstripped natural water recharge, but are expected to continue growing, resulting in a deepening arid urban water crisis. … The situations in arid and semi-arid cities like Phoenix, Arizona; Bamako, Mali; or Dubai, UAE, differ in their particulars, but rhyme in their impending disastrous trajectory. These, and other arid-region cities, are approaching the edge of an ecological cliff: dependent on sustaining growth, which itself requires a growth in water supplied by faraway and finite sources, and delivered by aging infrastructure. But water in dryland regions is getting scarcer and supplies more unpredictable.