13 U.S. coastal cities sinking beneath the waves

U.S. Cities Are Sinking, Some at a Fraction of a Millimeter per Year

Recent research indicates that around 32 coastal cities in the United States are experiencing gradual subsidence, a process that can range from a whispering few millimeters per year to more pronounced six millimeters annually. The phenomenon, described by Virginia Tech geophysicist Manoochehr Shirzaei as a “slow-moving yet widespread hazard,” underscores a looming challenge for urban planners and disaster risk managers.

What Drives Subsidence?

• Infrastructure Weight – The mass of skyscrapers, bridges, and other heavy structures exerts downward pressure on the ground.
• Water Extraction – Drawing groundwater from aquifers can cause underlying layers to collapse.
• Glacial Legacy – Residual effects from the last Ice Age influence soil and rock stability.

Why Should We Care?

Coastal regions worldwide already face catastrophic flooding as sea levels rise. Adding subsidence can triple global vulnerability, a 2019 study found. In the United States, the combined impact of sea‑level rise and subsidence could expose $109 billion of coastal property to high‑tide flooding by 2050, according to Shirzaei’s calculations.

Solutions Are Within Reach

Shirzaei emphasized that subsidence can be managed without breaking the bank. “We still have sufficient time to mitigate this risk,” he told Business Insider. The key: proactive measures and engineering innovations can stabilize ground levels before the next wave of flooding.

Top U.S. Cities Experiencing the Highest Subsidence

Listed in geographical order starting from the northern East Coast:

1. Boston, Massachusetts – Rapid urban development pushes the ground downward.
2. New York City, New York – Dense, high‑value real estate exerts substantial pressure.
3. Philadelphia, Pennsylvania – Industrial activity and water extraction contribute to sinking.
4. Miami, Florida – A tropical hotspot where subsidence and sea‑level rise intersect.
5. Houston, Texas – Petroleum infrastructure and heavy construction create downward strain.

These findings highlight an urgent, yet solvable, crisis that demands prompt, calibrated action from governments, scientists, and local communities.

Boston, Massachusetts

Boston’s Subsurface Story

Shirzaei and collaborators highlight pronounced subsidence disparities across the city. The uneven sinking, spanning roughly 1 mm to 4 mm annually, exerts varied pressure on infrastructure.

• Some neighborhoods experience a yearly drop of about 1 mm.
• Other sectors settle nearly 4 mm per year, amounting to roughly 4 cm over a decade.

New York City

NYC is Shrinking by About 1.5 mm Every Year

The Big Apple’s skyline is gradually dropping 1.5 mm per year, according to a 2024 study co‑authored by Shirzaei. Three airports in the region are also sinking, with rates that reflect the city’s broader subsidence problem.

Airport Submersion Rates

• JFK is sinking at 1.7 mm per year.
• LaGuardia is falling at 1.5 mm per year.
• Newark is dropping at 1.4 mm per year.

LaGuardia’s Countermeasures

LaGuardia has already built water pumps, berms, flood walls, and flood doors to protect the airport from rising levels. Prior estimates projected monthly flooding by 2050 and full submersion by 2100—those numbers do not yet account for the ongoing subsidence.

Implications for the Lower Manhattan Sunset

A man wades through the Morris Canal Outlet as the sun sets on the lower Manhattan skyline behind him. The scene captures a city that is physically receding, while its major transportation hubs are deliberately combatting the risk.

Jersey City, New Jersey

Jersey City’s Ground Sinks at 1.5 mm per Year

Container Ship One Manhattan Balances the Port

Shipping containers sit aboard the container ship One Manhattan at Port Jersey in Jersey City, New Jersey.

City Matches New York’s Sinking Pace

• Jersey City’s land subsides at roughly 1.5 mm per year, matching the progression of nearby New York City.
• Sub‑annual measurements rely on satellite radar.

InSAR Maps Granular Deformations

Shirzaei and co‑authors employ Interferometric Synthetic Aperture Radar (InSAR) to chart minute ground deformations across the city’s downtown.

Atlantic City, New Jersey

Beach Replenishment Project Near Ocean Casino Resort

Project Overview

• A strategic plan to restore sea‑bank sediments around the Ocean Casino Resort in Atlantic City.
• The initiative is designed to counteract sea‑level rise and coastal erosion.
• Key objectives include the stabilization of dune systems and the protection of marina infrastructure.

Environmental Context

The Atlantic City region experiences a subsidence rate of roughly 2.8 millimeters per year.

Subsequent settlement is a lingering reaction to the retreat of the Laurentide ice sheet, which once spanned vast portions of North America during the last Ice Age. The heavy ice mass forced the exposed land around its perimeters to bulge upward. The mid‑Atlantic area continues to settle downward as the ice sheet’s disappearance unfolded.

Benefit to Local Community

• Enhanced protection of coastal properties.
• Improved resilience for commercial enterprises such as the Ocean Casino Resort.
• Contribution to the broader effort of sustaining Atlantic City’s shoreline and its vibrancy.

Virginia Beach, Virginia

Virginia Beach residents brace for the future of sea level rise

In 2016, Ellen Ughetto, a homeowner on the Virginia Beach coast, began pre‑paring her house for the approaching storm‑season Hurricane Matthew. Today, the same shores confront a different kind of threat: rising tides.

• Virginia Beach is sinking at 2.2 millimeters a year.
• Local voters approved a $568 million plan in 2021 to protect the city’s infrastructure.
• Sea‑level concerns now shape community decisions, as residents invest in long‑term coastal resilience.

What “protecting” looks like

According to PBS News, the city’s new program funds seawall, dock, and flood‑gate upgrades that will guard against future inundation. The initiative reflects a shift from emergency response to sustainable planning.

Looking ahead

As climate change accelerates, Virginia Beach residents keep their eyes on the horizon—ready to keep the city’s shoreline safe.

Charleston, South Carolina

A flooded Charleston street turns into a dramatic scene

A vehicle passes through a Charleston street that has been inundated, showcasing the everyday impact of rising water levels on the city’s bustling streets.

Key facts about the city’s geography and sinking trend

• Geographical context: The downtown area of Charleston occupies a peninsula bounded by the Ashley and Cooper Rivers, providing a unique waterfront landscape.
• Submergence rate: Nationwide average sinking rates hover around 2.2 millimeters per year, yet specific districts are experiencing a steeper decline, reaching up to 6 millimeters annually.

These figures underscore the accelerating threat of sea‑level rise for Charleston’s historic waterfront, prompting urgent action from local authorities and residents alike.

Savannah, Georgia

Savannah Faces Rising Waters

Greenswood Fire Department’s Recent Effort

Firefighters Ron Strauss and Andrew Stevenson carried emergency meals to stranded residents, illustrating the city’s urgent need for proactive relief strategies.

Subtle Sinking Trend

Continued Shallow Drift

Savannah’s shoreline is subsiding at an average rate of nearly 2 millimeters per year, with certain districts experiencing a more accelerated decline, reaching up to 5 millimeters annually.

At-Risk Properties

• Flooding Outlook
  
  Over the forthcoming three decades, the climate analysis firm First Street projects that 13,000 or more homes in Savannah will confront heightened flood threats.
  
• Homeshare Percentage
  
  This figure translates into over 23% of the city’s total residences, underscoring the growing vulnerability of the area’s private sector.
  

Summary

The information above highlights both the immediate and long-term escaping flood risk facing the city’s families and property owners, propelling the city to invest in cutting-edge defense techniques.

Miami

Miami’s Barrier Islands Face a Surprising Sink

Luxury Towers and the Mainland Both Gradually Subside

Recent research has revealed that not only high‑rise condominiums on the barrier islands surrounding Miami are slowly sinking, but the mainland itself is also experiencing a modest downturn. The study, undertaken last year, points to a contractile phenomenon that could be driven by vibration from nearby construction activity.

• High‑rise Towers: Luxury residences on the islands are gradually dropping in height at a noticeable rate.
• Mainland Submergence: The mainland’s elevation is receding by approximately 0.5 millimeters each year.

These findings suggest that both built‑up coastal structures and the surrounding natural terrain are susceptible to gradual downward shifts. Continued monitoring is essential to understand the full extent of the sinking trend and to guide future urban planning decisions.

Mobile, Alabama

Mobile, Alabama: Coastal Urban Resilience

Location & Landscape

Mobile’s downtown anchors the southern edge of Mobile Bay, an inlet that opens toward the Gulf of Mexico.

Sea‑Level Challenges

• Annual tide rise averages 1.87 mm in the Mobile area, gradually reshaping the city’s waterfront.
• Regional rainfall is among the highest in the United States, intensifying flood risks for the Gulf Coast.

Disaster Preparedness

The city’s official website urges every resident to assemble a flood‑survival kit that includes:

• Canned food for extended shelf life.
• Flashlights to illuminate power‑outage scenarios.
• Water‑purification tablets for safe drinking supplies.

Key Takeaway

Mobile’s community resilience hinges on both long‑term tide‑rise adaptation and daily emergency preparedness, ensuring the city remains ready for coastal and climate‑related challenges.

Biloxi, Mississippi

b>Biloxi’s Evolving Ground: Rapid Subsidence Threats

Morning residents in Biloxi, Mississippi, watched Courtney Green prepare hurricane‑board supports on his front door as a severe storm loomed.

Key Findings on Biloxi’s Ground Stability

• Biloxi exhibits the most pronounced subsidence among U.S. cities examined by Shirzaei’s research team.
• On average, the city is sinking roughly 5.6 millimeters per year, though local variation is substantial.
• Certain city sectors may be experiencing subsidence rates as high as 10 millimeters annually.

Implications for Residents and Infrastructure

• The rapid subsidence increases the likelihood of structural damage during hurricanes.
• Emergency officials recommend regular ground‑monitoring and infrastructure reinforcement plans.

Next Steps for Biloxi’s Community

Biloxi residents and local authorities are urged to:

1. Install protective supports like those used by Green.
2. Engage in ground‑monitoring programs to detect early subsidence signs.
3. Coordinate with engineering experts to design long‑term resilience strategies.

New Orleans

New Orleans Faces Accelerated Flood Threat

Heavy rain on Bourbon Street highlights a growing crisis. In 2023, a relentless storm turned a celebrated party hotspot into a flash flood scene, underscoring the urgent need for adaptation.

Key Findings

• The city’s average sea level is rising at a rate of 1.3 mm per year.
• 99.6% of all properties in New Orleans are projected to experience flooding within the next 30 years.

Implications for Residents

Local governments and homeowners must urgently review building codes, invest in resilient infrastructure, and develop comprehensive flood‑management plans to safeguard communities.

Houston and Galveston, Texas

Galveston Faces Rising Flood Threats

A resilient shop owner, Shirzaei, has carefully assembled sandbags around a storefront to brace the building against the looming street‑level flooding that is targeting Galveston, Texas, after the destructive Hurricane Beryl.

Groundwater Extraction Triggers Decades‑Long Settling

• Shirzaei’s research reveals that Galveston is sinking more than 4 millimeters a year.
• Inland regions of Houston, where groundwater extraction has been ongoing for decades, have also experienced significant settling.

As the region’s flooding continues to intensify, the local community’s proactive efforts—including the strategic deployment of sandbags—demonstrate a strong commitment to mitigating the outsized impact of the storm.

Corpus Christi, Texas

Corpus Christi Faces Accelerating Ground‑Sinking Amid Flood‑Season Worries

Eyewitnesses capture the 2020 Hurricane Hanna floods, but the city’s subsidence continues to grow.

Source: Eric Gay/AP

Corpus Christi is now dropping at a rate of nearly 3 mm every year—an alarming trend that many experts trace back to the region’s thriving oil and gas extraction industry.

Geophysics professor Mohamed Ahmed of Texas A&M‑Corpus Christi emphasized that underground drilling can stir movement around fault lines, which in turn may trigger land subsidence. He added, “Extraction generally initiates and activates movement around faults, and those could initiate land subsidence in some areas.”

• Subsidence Rate: 3 mm per year
• Suspected Cause: Oil and gas drilling
• Expert Insight: Fault‑line activity activated by extraction efforts

What This Means for Residents

As the ground keeps sinking, local authorities are pushing for tighter flood‑control measures and more robust land‑stability monitoring. Citizens are advised to stay alert to changes in street conditions and water‑level warnings.

What about the West Coast?

California Ground‑Sinking Study

Visitors Relax Near San Francisco’s Painted Ladies

A gentle gathering takes place in a park just in front of the historic Painted Ladies houses in San Francisco, where people sit while the historic houses provide a picturesque backdrop.

Minimal Subsidence Along Coastal Cities

• Shirzaei’s research team did not observe significant subsidence in California’s coastal urban areas.

Central Valley’s Subsidence Due to Groundwater Extraction

• In contrast, the inland Central Valley is sinking because of excessive groundwater extraction.

Oregon and Washington: Data Still Inconclusive

• Researchers simply do not yet have reliable data to determine the subsidence conditions in Oregon or Washington.