Will Mexico City Run Out of Water?

The Threat of Water Shortages in Mexico City

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, 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.

Water Shortages Worldwide

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.

The Impact of Aquifer Depletion

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.

On supporting science journalism

If you’re enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.

The Need for Sustainable Solutions

Overreliance on aquifers is part of a global trend. “Water [sources] that have been deep underground have been an insurance policy” against drought, Kapnick says, “but they are finite resources.”

Piecemeal construction as the city grew also created an inefficient and unwieldy water system that is difficult to repair, says Gabriel Eckstein, director of the Energy, Environmental and Natural Resource Systems Law Program at Texas A&M University. Bezaury says that improper maintenance of the region’s infrastructure has led to a system that loses up to 40 percent of its water to leaks.

Mexico City might be able to learn some lessons from elsewhere. In 2018 Cape Town’s 4.5 million people were hit by a drought that was much worse than any in the past. The city was already approaching the limits of water extraction, and it was almost entirely dependent on surface reservoirs. “The major problem in the Cape Town case was having one [type of] source of water that as a result of climate change was at much greater risk than it had been prior,” says Barton Thompson, a senior fellow at the Woods Institute for the Environment at Stanford University. He says all of Cape Town’s reservoirs were dangerously low because of a lack of rain. Even though Cape Town had “spent years conserving water,” the city’s continued growth left the system unable to adjust.

To prevent collapse, Cape Town “doubled down” on conservation efforts, Thompson says. Measures included restricting domestic and commercial use of water and reducing water consumption by farms surrounding the city. The restrictions were particularly onerous for businesses such as restaurants and hotels, forcing them to find alternative water sources. The Westin Hotel built its own desalination apparatus to take advantage of the seawater infiltrating its basement.

Conservation efforts pushed out the impending Day Zero date, staving off reservoir exhaustion until the winter rains came. Despite the reprieve, though, Cape Town is still in a precarious position. Cape Town was only saved because of “a combination of extreme conservation and luck,” Thompson says.

Other water-stressed areas around the world are trying to implement sustainable solutions. “The key thing cities can do to avoid these Day Zero situations is to diversify their water sources,” Thompson says, adding that “as water becomes scarcer, cities become far more creative in the way they try to diversify their supply.” San Diego has invested heavily in desalination, as well as in water recycling—filtering suspended solids and bacteria from a community’s sewage and storm runoff and using ultraviolet light to sterilize the filtered water. San Diego is also looking to exploit new external sources beyond the Colorado River, such as the nearby San Luis Rey River and local groundwater bas

SDGs, Targets, and Indicators

1. Which SDGs are addressed or connected to the issues highlighted in the article?

SDG 6: Clean Water and Sanitation

The article discusses the threat of water shortages in Mexico City and other cities around the world. This issue is directly connected to SDG 6, which aims to ensure availability and sustainable management of water and sanitation for all.

SDG 11: Sustainable Cities and Communities

The article highlights the challenges faced by Mexico City due to its inefficient and unwieldy water system, as well as the sinking of the city caused by the depletion of the aquifer. These issues are related to SDG 11, which focuses on making cities inclusive, safe, resilient, and sustainable.

SDG 13: Climate Action

The article mentions that climate change is changing the likelihood of extreme events, such as droughts, which are depleting Mexico City’s reservoirs. This connection to climate change aligns with SDG 13, which aims to take urgent action to combat climate change and its impacts.

2. What specific targets under those SDGs can be identified based on the article’s content?

Target 6.1: By 2030, achieve universal and equitable access to safe and affordable drinking water for all

The article highlights the threat of water shortages in Mexico City, indicating that achieving universal access to safe and affordable drinking water is a target that needs to be addressed.

Target 11.5: By 2030, significantly reduce the number of deaths and the number of people affected and substantially decrease the direct economic losses relative to global gross domestic product caused by disasters, including water-related disasters, with a focus on protecting the poor and people in vulnerable situations

The article mentions the risks faced by Mexico City due to its inefficient water system and sinking caused by aquifer depletion. This target focuses on reducing the impact of water-related disasters, which is relevant to the issues discussed.

Target 13.1: Strengthen resilience and adaptive capacity to climate-related hazards and natural disasters in all countries

The article highlights the impact of climate change on Mexico City’s water supply and the need for resilience and adaptive capacity. This target emphasizes the importance of addressing climate-related hazards and natural disasters.

3. Are there any indicators mentioned or implied in the article that can be used to measure progress towards the identified targets?

The article does not explicitly mention any indicators related to the identified targets. However, the following indicators can be used to measure progress:

Indicator 6.1.1: Proportion of population using safely managed drinking water services

This indicator can be used to measure progress towards achieving universal access to safe and affordable drinking water for all.

Indicator 11.5.1: Number of deaths, missing persons, and directly affected persons attributed to disasters per 100,000 population

This indicator can be used to measure progress in reducing the number of deaths, affected persons, and economic losses caused by water-related disasters.

Indicator 13.1.1: Number of deaths, missing persons, and directly affected persons attributed to disasters per 100,000 population

This indicator can be used to measure progress in strengthening resilience and adaptive capacity to climate-related hazards and natural disasters.

4. SDGs, Targets, and Indicators

Copyright: Dive into this article, curated with care by SDG Investors Inc. Our advanced AI technology searches through vast amounts of data to spotlight how we are all moving forward with the Sustainable Development Goals. While we own the rights to this content, we invite you to share it to help spread knowledge and spark action on the SDGs.

Fuente: scientificamerican.com

Join us, as fellow seekers of change, on a transformative journey at https://sdgtalks.ai/welcome, where you can become a member and actively contribute to shaping a brighter future.