13 coastal cities in the US that are slowly sinking

Yahoo

05-05-2025

Cities all over the world, including on the US East and Gulf Coasts, are sinking.
This phenomenon, called subsidence, can make extreme flooding worse and damage infrastructure.
From New York to Houston, these 13 cities are losing height each year.
Cities are sinking across the US, some at a few fractions of a millimeter each year, while others lose up to six millimeters a year.
This phenomenon, called subsidence, is a "slow-moving yet widespread hazard," said Manoochehr Shirzaei, a geophysicist at Virginia Tech who co-authored a study published in Nature in March that measured subsidence in 32 coastal cities in the US.
Sinking can come from the sheer weight of skyscrapers and infrastructure, or from people drawing water from underground. Some of it is leftover from the last Ice Age.
Coastal cities worldwide are already prone to catastrophic flooding as sea levels rise because of the climate crisis. Factor in sinking, and the world's vulnerability to future coastal flooding triples, according to a 2019 study.
In the US, sea-level rise combined with subsidence could expose $109 billion of coastal property to high-tide flooding by 2050, according to Shirzaei's calculations.
The good news is that there are relatively inexpensive solutions to subsidence, Shirzaei told Business Insider in an email.
"The key takeaway is that we still have sufficient time to manage this hazard," he said.
Here are the biggest cities that are sinking the most, according to his new study, in geographical order starting from the northern East Coast.
Boston, Massachusetts
Shirzaei and his co-authors have found that there's a lot of variation in subsidence throughout Boston. When sinking occurs at different rates like that, it can put extra strain on infrastructure.
For example, some areas of Boston are sinking about 1 millimeter per year, give or take. Others sink nearly 4 millimeters a year — which translates to almost 4 centimeters per decade.
New York City
The Big Apple is losing about 1.5 millimeters of height each year.
All three airports in the NYC area are sinking, too, according to a study Shirzaei co-authored in 2024. JFK is sinking about 1.7 mm per year, LaGuardia at 1.5 mm per year, and Newark's airport is clocking 1.4 mm per year.
LaGuardia, for one, has already installed water pumps, berms, flood walls, and flood doors. Previous estimates had Laguardia flooding monthly by 2050 and fully underwater by 2100 — and that's without subsidence.
Jersey City, New Jersey
Just across the Hudson River, Jersey City is matching NYC's pace of about 1.5 millimeters per year.
To measure sinking at such a granular level, Shirzaei and his co-authors mapped ground deformations using a satellite-based radar technique called InSAR (short for Interferometric Synthetic Aperture Radar).
Atlantic City, New Jersey
A little further south, Atlantic City has its neighbors beat with a subsidence of about 2.8 millimeters per year.
A portion of the East Coast's subsidence is a leftover reaction from the disappearance of the Laurentide ice sheet, which covered much of North America during the last Ice Age. The ice sheet's bulk caused the exposed land around its edges to bulge upward — and the mid-Atlantic region is still settling down from the ice sheet's retreat.
Virginia Beach, Virginia
Virginia Beach, Virginia, is sinking 2.2 millimeters per year. Meanwhile, sea level rise has become a growing concern for locals.
In 2021, residents voted in favor of a $568 million program to build infrastructure that guards against rising sea level, according to PBS news.
Charleston, South Carolina
Charleston is the most populous city in South Carolina and its downtown sits on a peninsula flanked by the Ashley River and Cooper River. The city overall is sinking at a median rate of 2.2 millimeters per year, though in some areas its more dramatic at a rate of 6 millimeters per year.
Savannah, Georgia
Savannah is losing almost 2 millimeters per year, though some areas are sinking as much as 5 millimeters per year.
Over 13,000 properties in Savannah are at risk of flooding over the next 30 years, according to the climate risk analysis group First Street. That's over 23% of all homes in the city.
Miami
Last year, a study found that luxury high-rises were slowly sinking on the barrier islands surrounding Miami, possibly due to vibration from nearby construction. Shirzaei found the mainland is sinking, too, by about half a millimeter each year.
Mobile, Alabama
Mobile is losing 1.87 millimeters per year. The Gulf Coast city experiences some of the highest volume of rain in the US, according to the city's official website, and encourages all residents to have disaster survival kits, including canned foods and flashlights, on hand in the event of a flooding emergency.
Biloxi, Mississippi
Biloxi has the most drastic subsidence of all the US cities Shirzaei's team assessed. On the whole, Biloxi is sinking about 5.6 millimeters per year, with a lot of variation. Some parts of the city may be sinking as much as 10 millimeters per year.
New Orleans
New Orleans is losing 1.3 millimeters per year. First Street reports that 99.6% of all properties in the city are at risk of flooding in the next 30 years.
Houston and Galveston, Texas
Shirzaei found that Galveston, Texas, is sinking more than 4 millimeters a year, but inland parts of Houston have also been sinking for decades due to groundwater extraction.
Corpus Christi, Texas
Corpus Christi is sinking almost 3 millimeters per year. Some researchers think local oil and gas drilling has contributed to subsidence, reported local ABC outlet KIIV
"Extraction, generally, we believe it initiates and activates movement around faults and those could initiate land subsidence in some areas," Mohamed Ahmed, a geophysics professor at Texas A&M-Corpus Christi, told the outlet.
What about the West Coast?
Shirzaei's team didn't find much subsidence in California's coastal cities, although the state's inland Central Valley is sinking due to groundwater extraction.
As for Oregon and Washington, the researchers simply don't have good enough data yet to say what's happening to the ground there.
Read the original article on Business Insider