The causes of land subsidence can be broken down into three main categories: groundwater extraction, sea level rise, and the sheer weight of modern infrastructure. 

First, the most visible reason is the weight of buildings. 

“When we have a city, we have millions of people clustered in a small area, and they bring all kinds of things: water, oil, groceries, building materials, roads, pavement, and concrete. All these things are concentrated in a small area,” Parsons said.

A study published in Earth’s Future found the total weight of the infrastructure in New York City to be about 1.68 trillion pounds. They then calculated the downward force exerted by these buildings and found greater impacts in areas with softer soil types, such as clay. 

These imprints then lead to land compression, causing the city to sink. 

Furthermore, in Jakarta, an abundance of hurried infrastructure development has led to increased pressure on the already sinking land. 

“One of the main causes of Jakarta sinking is the rapid construction of high-rises, skyscrapers, new apartments, and new malls,” said Anna Winoto, a Jakarta resident. “I don’t see any further controls or restrictions on building new skyscrapers, apartments, and high-rises.” 

The most notable cause of land subsidence is groundwater extraction, which is the process of pumping fresh water from underground aquifers through wells, according to QED Environmental Systems. 

Groundwater extraction can quickly become excessive and lead to land subsidence. 

“Groundwater and petroleum take up a lot of volume in the basins where there are all these sand and rock particles. When it’s under pressure, it holds up,” Parsons said. “If you start pumping a lot of groundwater out, then the ground drops because that empty space has collapsed now.”

In fact, overpumping groundwater is the leading cause of city sinkage, according to the World Economic Forum.

Finally, sea level rise is occurring as a result of global warming, and melting glaciers mainly affect coastal regions. 

A team of scientists led by Rutgers found that modern sea level rise is occurring at the fastest rate in 4,000 years, according to the Rutgers Climate and Energy Institute.

When the ground sinks and the sea level rises, a phenomenon known as relative sea level rise occurs. In New York City, this issue has been particularly apparent. 

“There’s about two millimeters a year of sinking and two millimeters a year of ocean rising. The biggest concern is that when you have storms coming in from the ocean, with that double feature of the city sinking at the same time, it allows water to start entering the city,” Parsons said.

Many important cities across the world are located on low-level coastal plains, which makes them especially susceptible to sea level rise. While some countries are building seawalls to prevent the inflow of excess water, this can also result in coastal erosion, as found by Reduce Flood Risk.

While land subsidence affects most U.S. urban areas, it also has a significant impact on cities worldwide. The most notable example is Jakarta, which is infamous for being the fastest-sinking city on Earth. 

“Jakarta sank 30 cm because of the groundwater pumping out,” Parsons said. 

PBS also reports that around 40% of the city is below sea level, with nearly half of the city becoming uninhabitable by 2050.

Jakarta is not alone. Cities such as Bangkok, Shanghai, Houston, and Mexico City face similar crises. 

“What concerns me is that the government doesn’t seem to do much about it other than move the capital to another province,” Winoto said. “We want a future in Jakarta, but yet there’s not much being done to avert the situation other than building a seawall, which is not going to last for long.”

The National Capital Integrated Coastal Development program, a $40 billion seawall project known as the Great Garuda, remains indefinitely postponed after ongoing lawsuits and environmental pushback. Meanwhile, the Indonesian government is continuing to relocate the capital to Nusantara on the island of Borneo, aiming for completion by 2028. 

However, local urban planning critics warn that most of Jakarta’s population, particularly lower-income residents, will be left behind. 

Additionally, flooding has been a significant issue in Jakarta, affecting 100,000 people and displacing 90,000 during the storms in March 2025, according to the Resilience Development Initiative in Bandung.

“We hoped that we would always have a home to come back to in Jakarta, but with the current situation, it’s likely that our home will no longer exist,” Winoto said. 

This same phenomenon has been occurring in the backyards of many Bay Area residents. Redwood Shores, a region of Redwood City built largely on reclaimed wetlands and landfill, is particularly susceptible to sinkage. 

“I live in Redwood Shores, and it’s really at risk to all this sort of stuff because it’s level with the ocean and was built on the marshes,” said Zoe Hardman, a Carlmont freshman. 

However, the change isn’t always noticeable. Since sinkage happens at just millimeters every year, it often goes unrecognized. 

“At first, you don’t see it, because it’s your whole house, your whole driveway,” said Christine Smith*, a longtime resident of Redwood Shores. “But over time, you can see the slope.”

In fact, subsidence is most obvious during floods, which the city is particularly prone to. First Street, which specializes in climate risk financial marketing, finds that 98.4% of Redwood Shores properties are at risk of flooding. Additionally, the Water Education Foundation notes that the city holds the greatest risk for severe flooding in California.

In December 2022, Northern California experienced significant rain events that led to flooding in Smith’s home. 

“The soil, which is basically landfill, was 100% soaked. And your house is on a foundation that is 100% soaked,” Smith said. “Your house is sinking, literally sinking.”

Not only did this incur expensive reparation fees for homeowners, but the excess rainwater also led to issues with drainage. Sewage and garbage seeped into many roadways.

“There were days when I could smell the sewage water in my street,” Smith said. 

Many are also concerned about the future of Redwood Shores if the sinking is not properly addressed.

“People would have to adapt and figure out how to protect their stuff depending on how high the flooding is,” Hardman said.

Despite this, many are looking for ways to mitigate the impacts of sinking cities. Residents, local officials, and nonprofit organizations are actively working toward solutions.

“The most common response to coastal flooding is to build seawalls that armor the coastline,” Parsons said. 

For example, Redwood Shores recently launched an initiative to expand its network of levees, protecting approximately 11,500 residents. While it can be difficult for smaller cities to grapple with these issues, partnering with larger organizations, such as OneShoreline, can help expedite the process.

“You need a bigger organization that can help you think through this and have that experience. You can work with them to implement their recommendations based on the scientific research,” said Sue Exline, the assistant director of Community Development and Transportation for Redwood City. 

Additionally, reducing urban development in vulnerable cities is another popular solution. By decreasing the weight of infrastructure, the land becomes less susceptible to sinkage. 

“Part of our role is to look at how high the building needs to be built, how much land you need to put up, and what the ground floor can look like,” Exline said. 

Beyond government initiatives, individuals are advocating for change. In Redwood Shores, community members have taken a stand against new construction.

“I try to oppose the new housing development because the more you build on the landfill, the more it’s going to sink and the more it’s going to use up the already strained resources,” Smith said.

The Sinking Cities Project, a global initiative led by Unbias the News and Hostwriter, seeks to highlight the dangers of sinkage and the necessity for change.

“It showed that there were clear, human actions that were leading to sea level rise and endangering lives,” said Ankita Anand, editor for Unbias the News and contributor to the Sinking Cities Project. “Our reporters wanted to hold governments accountable for their inaction, while depicting that climate change is a problem across the world.”

These solutions come at a dire time, when many cities are already facing the impacts of sinkage. It is imperative that local governments allocate funding and resources to mitigate the long-term effects. 

“We knew it was coming. It’s a huge problem with significant implications on our day-to-day lives, but we’re acting too late,” Winoto said.