Home / Environment / Cities Are Sinking: Global Subsidence Crisis Worsens
Cities Are Sinking: Global Subsidence Crisis Worsens
12 Aug
Summary
- Nearly all major cities face subsidence, with 44 sinking faster than sea levels rise.
- Building weight, groundwater extraction, and geology cause urban land to sink.
- New York, Shanghai, Miami, and San Francisco face significant sinking challenges.
A concerning global trend reveals that nearly all major cities are experiencing land subsidence, with many sinking faster than sea levels are rising. This gradual sinking of the ground surface is driven by various factors including the cumulative weight of massive urban structures, extensive groundwater extraction creating underground 'droughts', underlying weak geological formations, and the sheer mass of millions of buildings.
In the United States, New York City's approximately one million buildings contribute to an average subsidence of 1 to 2 millimeters annually. Miami, built on porous limestone and facing rising sea levels, is also at high risk, with projections suggesting significant portions could be below sea level by 2060.
Internationally, cities like Shanghai and Tokyo face similar threats. Shanghai's subsidence is exacerbated by construction on alluvial soil and heavy groundwater pumping. Tokyo, despite reduced groundwater extraction, sees its eastern districts vulnerable due to numerous high-rise projects near Tokyo Bay.
Other US cities like San Francisco and Houston also exhibit significant subsidence. San Francisco's Millennium Tower has sunk over 18 inches, while parts of the Bay Area are subsiding rapidly. Houston has experienced sinking of over 10 feet due to urban development and resource extraction.
The issue is a stark reality, with a 2022 study in Nature Sustainability finding that in 44 out of 48 studied major cities, land is sinking faster than the sea is rising. This ongoing crisis presents immense challenges for urban planning and resilience.
