Will Mexico City Run Out of Water?

May 10, 2024

By Jordan Kinard, Scientific American

May 10, 2024

The global press recently warned that as early as June 2024, Mexico City, home to 22 million people, could face “Day Zero”—the complete loss of fresh water at the taps. The situation on the ground, although dire, is more nuanced. “Day Zero is a bit of an exaggeration,” says Juan Bezaury, until recently the Mexico country representative at the Nature Conservancy. Instead, Bezaury says, Mexico City, North America’s largest city, is facing the exhaustion of the Cutzamala aqueduct system, which brings the metropolis up to 25 percent of its water, from reservoirs across the surrounding state of Mexico. Scientists say the persistent drought much of the country has suffered is depleting its reservoirs. “Climate change is changing the [likelihood] of these extreme events,” says Sarah Kapnick, chief scientist at the U.S. National Oceanic and Atmospheric Administration.

Even if total shutdown is an exaggeration, the threat of water shortages is high, and it is rising worldwide as well. Cape Town, South Africa, came perilously close to a Day Zero in 2018. Cities around the globe, from those in Colombia to India, are at great risk of losing fresh water. In April, Bogotá began rationing in response to drought.

Most of the rest of Mexico City’s water is drawn from the aquifer on which it is built, which brings its own risk. “The more the aquifer dries up, the more Mexico City sinks,” Bezaury says. Some parts of the city are sinking by up to 20 inches per year. He adds that Mexico City is already pumping more than twice the water from the aquifer that can be replaced by surface water infiltration. This deterioration cannot solely be attributed to climate, however. The population of the area has risen relentlessly. Centuries of development have compromised the aquifer’s replenishment. “We paved the hell out of [the Valley of Mexico],” Bezaury says, “and there is almost certainly no infiltration.” Most of the rainwater lingering on the surface evaporates.

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