12 Rapidly Sinking Cities.

Alexandria, Egypt

The second largest city in Egypt, historic Alexandria sits along the Nile Delta, which has slowly been eroding the land along it. According to a 2018 study, due to overpopulation and natural and anthropogenic land deformation, the coastal city’s future most likely includes severe sea encroachment. Alexandria faces a loss of arable land and aquaculture resources, destruction of infrastructure, population migration, saltwater intrusion, and salinization of groundwater resources. By 2100, scientists expect about 1,000 square. miles of land will be inundated by seawater, changing the lives of about 5.7 million people who live in Alexandria and other communities in the northern Delta.1

Amsterdam, Netherlands

Subsidence and climate change-fueled sinking has been an issue in the Netherlands since 1000 AD due to the country’s soft peatland ground. Only about 50 years ago, the Netherlands started implementing mitigation measures, though it might have come too late. Amsterdam is one of a few coastal Dutch cities currently sitting below sea level. The iconic Dutch windmills used to irrigate the extra water inland has contributed greatly to the coast’s growing instability. By 2050, the cost of repairing and maintaining damaged infrastructure is expected to reach € 5.2 billion. By 2100, it is expected that the sea level along the Netherlands will rise to about 2.5 feet.

Bangkok, Thailand

Scientists anticipate that by the next century, the rising sea level will submerge Bangkok in its entirety. Sea level rising, bringing with it food insecurity and infrastructure damage, will endanger and uproot millions of people. The city’s sinking future is all but definite in part due to the foundation of Bangkok: a layer of soft clay (known as “Bangkok clay”) above a swampland. In 2020, parts of the city had already sunk a meter below sea level. Despite improvements to infrastructure and subsidence management, sinking and flooding have persisted, with a dire future ahead if sweeping changes are not implemented.

Charleston, South Carolina

The peninsula city of Charleston has a long history of flooding. When the area was first colonized, the land already sat at low elevation. This factor combined with rising sea level and worsening storms have stressed the land even further. The loose salt-marsh sediment that Charleston resides on has contributed to the sinking. In a five-year period ending in 2013, the number of flood days experienced by Charleston rose to 23.3 days per year, a massive jump from the average 4.6 days per year felt in the 1960s. The 2014 National Climate Assessment named Charleston as one of the U.S. cities most threatened by rising sea level.

Dhaka, Bangladesh

Dhaka has some of the most severe subsidence in the world. The problem was first actualized after people started investigating the increased frequency of flooding. Bangladesh produces just a fraction of global emissions driving climate change yet it is one of the countries most vulnerable to ripple effects due to the positioning of the Ganges Delta, the world’s largest river delta.

Bangladesh is one of the most densely populated countries in the world, and the land in Dhaka is low-lying, making it very vulnerable to rising sea level as a growing number of people flock to this more inland city from coastal villages. Due to climate change and subsidence, scientists expect rising sea levels with cover about 17% of the coastal land by 2050, displacing millions of people as a result.

Ho Chi Minh City, Vietnam

Rapid urbanization and population growth has led Ho Chi Minh City to sink below sea level. The stress of human activity has caused severe subsidence and increased flood risks. Subsidence has been observed in the city since 1997, though officials have disagreed on the impacts of the problem. Accurate data is scarce due to poor monitoring of the city’s subsidence and groundwater extractions. There is also rampant unregistered extraction from aquifers for domestic water supply adding to the worsening problem.

Houston, Texas, USA

Groundwater pumping and oil and gas extraction over several decades have made Houston’s subsidence problem severe. The Houston-Galveston region is one of the largest areas of subsidence in the U.S. By 1979, almost 10 feet of subsidence (about 3,200 squares) occurred in the region. Infrastructure damage, flooding and loss of wetland habitats have increased in recent years. Subsidence of the low-lying land has already altered Houston’s position on the coastline, with changes visibly apparent. The San Jacinto Battleground State Historical Park is now partly submerged.

Jakarta, Indonesia

While Jakarta is taking steps to reduce groundwater extraction due to subsidence, the city has continued sinking rapidly, fasting than any other large city in the world. Jakarta’s subsidence has worsened as many illegal users continue to tap aquifers. If illegal aquifer usage continues, it is expected that parts of North Jakarta will sink by an additional 2 to 4 meters by 2100.The illegal wells dug have had a major impact on the rapidity of sinking. In 2017, 40% of the city was below sea level.

Lagos, Nigeria

Much of the Nigerian coast is already low-lying but the stress of a rapidly growing population has exasperated the issue. The continental shelf Lagos rests on is sinking, bringing the Gulf of Guinea closer while the Sahara Desert grows larger due to drought. As Africa’s largest city, those living in Lagos are at the mercy of flooding dangers, erosion, and food insecurity. Millions of people could be displaced in the coming years.

Miami, Florida

The low-lying region of South Florida is extremely susceptible to rising sea level. Miami is particularly vulnerable due to its dense population and infrastructure. The southern tip of the Florida peninsula has already risen a foot since the 1990s. City planners are preparing for a two-foot increase by 2060 and by 2100, five to six feet. This eventuality will displace about a third of the region’s population since Miami would become uninhabitable. The city is in a precarious position currently. Just six inches of sea level rise would threaten Miami-Dade’s drainage system which keeps the swamp land out of densely populated communities.

New Orleans, Louisiana, USA

With the nearby Mississippi Delta, New Orleans has long lacked a strategy for mitigating subsidence. A persistence of oil and gas extraction for economic benefits with little thought to environmental impacts has worsened the land’s subsidence. Human activity accounts for multiple centimeters of subsidence each year. Increased flood risks from rising sea levels have also had an impact on the city’s instability. Infrastructure has already shown evidence of damage which will result in costly spending in the future.

Venice, Italy

Venice has gradually been sinking for many years due to rising sea levels and increased flooding. While this problem has been known for quite some time, the issue gained worldwide attention in 2019 when the city was devastated by extreme flooding. The frequency of high tides peaked that year causing the worst flooding in decades. Natural barriers currently protecting the city are expected to drop by 150 to 200 millimeters in the next 40 years, making the city more vulnerable.