Mexico: World's 'sinking' city

Category
Environment
Published
5th Mar, 2024

Context

A new study in Advancing Earth and Space Science unveils a concerning reality - Mexico City is gradually sinking 30 centimetres every year.

Dimension 1: What’s at ‘stake’?

Mexico Cityis one of the largest metropolises globally. It is the home to over 21 million people.
This subsidence, which has persisted for over a century, has intensified in recent years, reaching a staggering half a metre annually.
The potential for an additional descent of 30 metres is a looming threat, contingent on the absence of a severe water crisis.

Similar shrinking patterns around the world
Jakarta	Jakarta is the largest city and capital of Indonesia. Jakarta is congested, polluted, prone to earthquakes, and rapidly sinking into the Java Sea. It has been described as the world’s most rapidly sinking city and it is estimated that one-third of the city could be submerged by 2050.
Florida	Low-lying south Florida, at the front line of climate change in the US, will be swallowed as sea levels rise
Islands in India	India has a fragile network of over 1,382 islands. However, several of these islands are under threat due to unseasonal cyclonic storms, sea erosion and new development projects. One such island in Lakshadweep has entirely disappeared from the map. Islands across the country that are under threat: Lakshadweep, Vaan island, Andaman and Nicobar islands, Ghoramara, Majuli island, Munroe Thuruthu
Joshimath (Uttarkhand)	Joshimath, the ancient Uttarakhand town has become a cause of concern. Though the town of Joshimath has been witnessing cracks emerging for the past two decades, things have escalated over a few days when the area was declared a disaster prone region.

Dimension 2: Reason behind the situation

Extensive extraction of water: The primary culprit behind this phenomenon is the extensive extraction of underground water, with 70 percent of the city's drinking water sourced from aquifers located in a

The Cutzamala water system, a network of reservoirs, pumping stations, canals and tunnels, supplies about 25% of the water used by the Valley of Mexico, which includes Mexico City.

Destruction of protective walls: The city's history plays a significant role in this subsidence. Originally established on the Aztec city Tenochtitlán and Lake Texcoco, the Spanish arrival in the 16th century led to the destruction of protective walls that prevented flooding.
Climate change: Years of abnormally low rainfall, longer dry periods and high temperatures have added stress to a water system already straining to cope with increased demand.

Dimension 3: Reversal

The damage is almost irreversible due to the weight of the city and its shallow foundations causing soil compaction.
Unless water levels rise significantly, the subsidence is likely to persist.