The 28 Biggest U.S. Cities Are Sinking, Satellites Say. Here's Why
A new study using recent satellite data finds that all cities in the United States with populations ... More of more than 600,000 are sinking — and Houston, Texas, the most.
America's most populous cities are finding themselves on increasingly unstable ground, with data from satellites revealing that 28 major U.S. cities are sinking, according to new research. About 34 million people are potentially affected, about 12% of the population. The culprit is the extraction of water from underground aquifers, many of which crumble and compact in the ground.
The research, published in Nature Cities, revealed that metropolises, including New York, Dallas-Fort Worth, Houston and Seattle have urban areas that are sinking by between two and 10 millimeters per year.
At least 20 percent of the urban area in each of the 28 cities is sinking, the data suggests, though the problem is much more serious in most affected cities, with 25 of the 28 cities having at least 65% of the urban area sinking.
A new study using recent satellite data finds that all cities in the United States with populations ... More of more than 600,000 are sinking to one degree or another.
The 28 cities are Austin, Boston, Charlotte, Chicago, Columbus, Dallas, Denver, Detroit, El Paso, Fort Worth, Houston, Indianapolis, Jacksonville, Las Vegas, Los Angeles, Memphis, Nashville, New York, Oklahoma City, Philadelphia, Phoenix, Portland, San Antonio, San Diego, San Francisco, San Jose, Seattle and Washington, D.C.
It's putting more than 29,000 buildings at risk in high and very high damage risk areas, say the authors, with even a slight shift of the land downward threatening the structural integrity of buildings, roads, bridges and dams.
The research is based upon radar measurements from the Sentinel-1 constellation of satellites.
The research is based upon radar measurements from the Sentinel-1 constellation of satellites that use their Synthetic Aperture Radar instruments to measure land elevation changes in all U.S. cities with populations exceeding 600,000. The data was used to create high-resolution maps of subsidence in the 28 most populous U.S. cities. The same technology is often used to measure changes in sea ice, oil spills and land-use change.
"A lot of small changes will build up over time, magnifying weak spots within urban systems and heighten flood risks," said Leonard Ohenhen, lead author and a former graduate student at Virginia Tech's Earth Observation and Innovation Lab.
The fastest-sinking city is Houston, where more than 12% of its area subsides more than 10 millimeters (about 1/5 inch) per year and some localized spots up to 5 centimeters (2 inches) per year. Two other Texas cities, Fort Worth and Dallas, are not far behind. Some localized fast-sinking zones in other places include areas around New York's LaGuardia Airport and parts of Las Vegas, Washington, D.C. and San Francisco.
There is a similar localized impact in New York, Las Vegas and Washington, D.C. However, New York, Chicago, Seattle, Denver [and five other cities] are sinking by the least amount, at about two millimeters per year.
Much of New York City is slowly sinking, with some hot spots, especially around La Guardia Airport, ... More and parts of Jamaica Bay and Staten Island.
In terms of population density, eight cities (New York, Chicago, Los Angeles, Phoenix, Houston, Philadelphia, San Antonio and Dallas) account for more than 60% of the people living on sinking land. These same eight cities have had more than 90 significant floods since 2000, state the authors, with lowering topography as one of the causes.
The cause, according to the researchers, in 80% of cases is the extraction of groundwater, with fast-growing cities rapidly expanding their extraction of freshwater from aquifers faster than they can be replenished. In Texas, the problem is exacerbated by the pumping of oil and gas, the paper says. 'As cities continue to grow, we will see more cities expand into subsiding regions,' said Ohenhen. 'Over time, this subsidence can produce stresses on infrastructure that will go past their safety limit.'
The authors suggest managing groundwater extraction more carefully, using more resilient buildings and infrastructure, and monitoring more. 'As opposed to just saying it's a problem, we can respond, address, mitigate, adapt,' said Ohenhen. 'We have to move to solutions.'
In 2023, scientists discovered that New York City's over one million buildings — and relentless construction — may be causing the city to subside, exacerbating the risk of future flooding.
Wishing you clear skies and wide eyes.
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