Sinking City Of The World

[Darci Carlton]

Some cities are sinking due to increasing sea levels slowly encroaching on their coasts, while others are sinking because of excessive groundwater pumping that creates a change in pressure and volume that causes land to sink.

Jakarta is sinking up to 6.7 inches per year due to excessive groundwater pumping (which creates a change in pressure and volume that causes the land to sink). Much of the city could be underwater by 2050.

The Indonesian government recently approved a plan to move the capital 100 miles away from its current location on the island of Java in order to protect its 10 million residents from more flooding. The move would take about 10 years and cost $33 billion.

A 2012 study from the University of Plymouth found that a sea level rise of three to nine feet would " have a catastrophic effect on the human activities in these regions." Global sea levels are expected to rise 6.6 feet by the end of this century.

Italy began building a flood barrier consisting of 78 gates across its three inlets in 2003. It's known as Mose. The barrier was supposed to be completed in 2011, but will likely not be ready until 2022.

To help prevent flooding, especially during Thailand's summer rainy season, an architecture firm built an 11-acre park that can hold up to 1 million gallons of rainwater called Chulalongkorn University Centenary Park.

Like Bangkok's Chulalongkorn University Centenary Park, the Dutch have built "water parks" that double as reservoirs for the swelling water levels in a project called Room for the River, as well as enormous storm surge barriers.

Environmental author Jeff Goodell previously told Business Insider that " there's virtually no scenario under which you can imagine [Miami] existing at the end of the century" and referred to it as "the poster child for a major city in big trouble."

Subsidence happens for a variety of reasons. Often it's from extracting water, oil, natural gas or minerals from the ground through activities like pumping, fracking or mining. Earthquakes can cause subsidence, as well as erosion, the formation of sinkholes, soil compaction and other geologic processes.

All this is happening while climate change is causing ice in the polar regions of the world to melt, resulting in an increased volume of seawater in the world's oceans. Coastal cities are not only in danger of submerging, but also of natural disasters like hurricanes.

Java is the most populous island in the world; freshwater is scarce and groundwater is a hot commodity. The illegal boring of wells in and around Jakarta is understandable in a city where the local government can't provide fresh water for its 9 million residents, not to mention the millions of others who commute to work in the city. But the island's wetlands are being drained by illegal wells, leading to the subsidence of the entire landscape.

Joko Widodo, Indonesia's long-time president, has proposed that the capital city be moved to a location 800 miles (1,300 kilometers) away in Borneo. The new city will be called Nusantara, and construction has already begun.

"The weight and local geology is a secondary factor in the case of New York," says Matt Wei, a geophysicist and professor in the Graduate School of Oceanography at the University of Rhode Island. "The dominant reason they city is sinking is glacial isostatic adjustment."

New York is in an interesting position because it's actually sinking due to the fact that the last ice age caused it to rise because the heaviest sheets of ice were inland. Now that the ice has melted, the middle of North America is rising, while the edges sink.

"In New York, the average sinking is between 1 to 2 millimeters [0.03 to 0.07 inches] per year, plus 3 to 4 millimeters [0.11 to 0.15 inches] per year due to sea level rise," says Wei, who co-authored a 2023 study about New York's plight. "The relative sea level rise might be millimeters per year. Depending on the site elevation, you might expect 0.4 to 0.6 meters [1.3 to 1.9 feet] of relative sea level rise in 100 years."

Houston, Texas, located on the Gulf of Mexico, is experiencing rapid subsidence. Built on the flat, low mouth of a river delta, Houston has never had far to fall in terms of elevation, but like Jakarta, excessive groundwater extraction has been the main culprit in its sinking.

The port city of Rotterdam in the Netherlands is sinking at a rate of around 0.6 inches (1.5 centimeters) per year, and at this point the city is already around 90 percent below sea level. Although the Dutch are famous for protecting themselves from the sea with technologies like dams, dikes, pumps and seawalls, these are only short-term fixes.

Part of the problem has to do with the country's famous windmills. For centuries the windmills have been used to drain the country's peatlands, a special kind of wetland that sequesters carbon in the form of peat-forming organic matter. Draining the peat bogs causes subsidence at a maximum rate of 3 inches (8 centimeters) per year. Combined with factors like seas that are expected to rise by 5 to 18 inches (14 to 47 centimeters) by 2050, among other factors, the future of low-lying cities such as Rotterdam is uncertain.

The most famous sinking city by far is Venice, Italy. Home to an intricate web of canals, Venice was built in the 5th century and has always had the Adriatic Sea, with its exceptional acqua alta high tides, to contend with. The city's founders partially knew what they were doing when they built the city on a salt marsh completely surrounded by water. What they couldn't know was that the city sits on a tectonic plate.

Venice is subsiding at the rate of 0.08 inches (0.2 centimeters) every year due to groundwater extraction while sea levels rise, and its heavy buildings have been compacting the underlying soil for centuries. But plate tectonics is also causing Venice to sink, as well as tilt slightly to the east. This means the western side of the city is higher than the eastern side.

Sinking cities are urban environments that are in danger of disappearing due to their rapidly changing landscapes. The largest contributors to these cities becoming unlivable are the combined effects of climate change (manifested through sea level rise, intensifying storms, and storm surge), land subsidence, and accelerated urbanization.[2] Many of the world's largest and most rapidly growing cities are located along rivers and coasts, exposing them to natural disasters. As countries continue to invest people, assets, and infrastructure into these cities, the loss potential in these areas also increases.[3] Sinking cities must overcome substantial barriers to properly prepare for today's dynamic environmental climate.

The vast majority of sinking cities are located in coastal lowlands. These areas are particularly vulnerable to climate related hazards, but since ancient times, have also been preferred areas for human settlement. Soil fertility, availability of fresh water from rivers, accessibility due to flat topographical relief, and sea and waterways allowing for trade routes, have long made coastal plains valuable agricultural and economic resources. Throughout history, these areas have continued to develop, and today, are some of the most densely populated regions in the world.[4]

The growing physical risks to many coastal cities stem from a combination of factors relating to rapid urbanization, climate change, and land subsidence. Many of these natural hazards are largely anthropogenic in origin.[2] In many cases, the fundamental aspects that lead to sinking cities become tightly interwoven, and over time, are increasingly difficult to resolve.

For the first time in human history the majority of people live in urban areas. The United Nations estimates that approximately 68% of the world's population will be living in urban areas by 2050.[3] Urbanization has vast implications including the urban planning, geography, sociology, architecture, economics, and public health of a region.[6] The rate at which urbanization occurs is also important. Slower rates of urbanization allow city planners time to make thoughtful planning decisions. Once cities reach maturity, it can take decades for local governments to develop, fund, and execute major infrastructure projects to alleviate the issues brought on by rapid urbanization.

In particular, some regions in Asia are currently experiencing unprecedented urban growth. Currently, the Asian urban population is increasing by 140,000 per day and is expected to nearly double from 1.25 billion in 2006 to 2.4 billion by 2030.[2] The more troubling fact is that much of this growth is taking place along the coasts. In China, population growth in urban coastal locations was three times the national growth rate.[2] Rapid increases in population growth challenge the carrying capacity of these urban environments often leading to mismanagement of natural resources. For sinking cities, the most common result has been over-extraction of groundwater ultimately resulting in land subsidence.

Low-lying cities are especially prone to the most devastating effects of climate change. The risks posed by climate change will continue to grow into the next century, even if a dramatic reduction in greenhouse gas emissions is achieved, due to the built-in momentum from previous emissions.[2] Moreover, recent reports by the United Nations have shown that climate change may be accelerating rather than slowing down. The 2019 Emissions Gap Report confirmed that GHG emissions continue to rise, despite highly publicized political commitments.[7] The report goes on to emphasize that countries must increase their Intended Nationally Determined Contributions threefold to remain below the 2 C goal and more than fivefold to achieve the 1.5 C goal.[7]

Coastal cities will bear the largest impacts of climate change due to their proximity to the sea. Storm surges and high tides could combine with sea level rise and land subsidence to further increase flooding in many regions.[8] Oftentimes even recently completed infrastructure projects have not properly accounted for the rapidly changing climate. Asia's coastal megacities are particularly at risk as certain cities' flood protection measures have been cited as inadequate even for 30-year flood events.[2]

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