Wiped off the map? The deadly consequences of the world's sinking cities

In 2017, Houston was flooded as water from a reservoir added to floodwaters from Tropical Storm Harvey. Photo / AP

It's hard to fathom how a city of 10 million people can pick up and move to an entirely new island.

But Jakarta isn't the only city with that mammoth task ahead. There are several others at risk of sinking around the world, reports news.com.au.

This week Indonesia's president Joko Widodo announced the country's capital will move to a site in the sparsely populated East Kalimantan province on Borneo island, known for rainforests and orangutans.

Jakarta is sinking faster than anywhere else in the world and must move because it's overcrowded and over-polluted.

Experts have labelled the plan as 'very risky', warning if the country is not careful it will just create the same problems elsewhere.

Here's a look at the other cities at risk of going under.

Jakarta is sinking faster than anywhere else in the world. Photo / 123rf

NEW ORLEANS

The US city is vulnerable to flooding because it's sinking, built on loose soil and situated close to the coastline.

Scientists say it's going under at a rate of 1cm a year.

The National Academy of Sciences projected in 2016 that New Orleans could be one of the hardest hit cities in the world when it comes to rising sea levels, along with Manila, Jakarta, and Bangkok.

According to the The Times-Picayune, by the 1930s one-third of the city was below sea level, and by the time Hurricane Katrina struck in 2005, that number was up to about 50 per cent.

The soil subsidence has deadly consequences, with several houses exploding in the city from 1975, injuring dozens of people. Buried gas lines twisted and ruptured, leaving the gas to accumulate in cavities beneath concrete slabs or wafting up into attics.

New Orleans is vulnerable to flooding because it's sinking, built on loose soil and situated close to the coastline. This is from 2005. Photo / Getty

MANILA

Scientists reported that the mean sea-level in Manila Bay in the Philippines abruptly rose in the late 1960s.

In September 2009 Tropical storm Ondoy brought one month's worth of rain in less than a day and left more than 80 per cent of the city submerged in water.

Hundreds of people were killed and thousands more were left displaced.

The sinking is being caused by catastrophic subsidence from groundwater being pumped out from below, often through unregulated wells for homes, factories and farms.

The provinces of Pampanga and Bulacan have sunk between 4 and 6cm annually since 2003, according to satellite monitoring.

Residents wade through the floodwaters as they evacuate to safer grounds following flooding in Calumpit township, Bulacan province, north of Manila, in 2011. Photo / AP

BANGKOK

The Thailand government released a report three years ago that warned the capital city could be under water within 15 years.

While that might sound shocking, with an elevation of only 1.5m above sea level and a sinking rate of 2cm per year, the outlook for Bangkok doesn't look good.

One of the culprits is the immense number of buildings in the city.

The Sinking cities report revealed about 700 buildings with 20 floors or more and 4000 buildings with 8-20 floors are putting considerable pressure on the land.

For the 10 million people living there, flooding is a recurring and deadly problem.

The 2011 flood event cost the country US$46 billion in repairs and rehabilitation - US$8 billion of that spent on Bangkok alone. More than 800 deaths were recorded and 13 million people were affected by the flooding.

For the 10 million people living there, flooding is a recurring and deadly problem in Bangkok. Photo / AP

HOUSTON

The US city has been sinking for decades.

According to data from the US Geological Survey, parts of Harris County, which includes the Texan metropolis, have dropped between 3 and 4m since the 1920s.

Some areas are sinking by as much as 5cm a year.

Like other cities sinking, Houston has been drawing too much groundwater, leaving the region prone to serious flooding.

Houston sits in one of the nation's largest subsidence bowls, and there are several other smaller bowls that drop in elevation, leaving water to pool in these areas.

SHANGHAI

The central business district has sunk 2.6m since 1921 when the first surveys were done.

Excessive groundwater use is a major factor here too but there's also a lack of sediment recharge as sediment is trapped by upstream dams or is extracted for building material.

Like Bangkok, heavy buildings also play a part. In 2012, an 8m long crack opened up at the foot of the Shanghai Tower project.

The sinking was estimated to have cost the city more than US$2 billion between 2001 and 2010.

Subsidence affects more than 50 cities, where 78,858 sqkm of land has dropped at least 20cm.

Workers carry plastic plants over flooded waters as heavy monsoon rains continue in Manila this month. Photo / AP

LAGOS

A study from 2012 revealed that because Nigeria's coastline is so low, a sea level rise of just 1 to 3m "will have a catastrophic effect on the human activities in these regions".

The city with a growing population of 21 million people - the most populous city on the African continent - is especially vulnerable because of the lack of adequate drainage systems and subsidence caused by groundwater extraction.

Some estimates suggest that a sea level rise of 20cm could cause 740,000 people to lose their homes across Nigeria.

Its low coastline continues to erode.

BEIJING

A 2016 study revealed the city is sinking by as much as 10cm in some areas each year.

Again like other sinking cities, the problem is due to depleting groundwater, with over-extraction causing the soil to dry up and compact.

The study noted Beijing was ranked as the fifth most water-stressed city in the world.

Groundwater is the main water source for the city, with estimates the capital requires 3.5 billion litres of water per year.

The rapid sinking could affect buildings and public works projects, including the city's rail network.

DHAKA

It's estimated rising sea levels could flood 17 per cent of the city of Bangladesh, leaving about 18 million of citizens displaced by 2050.

The city is sinking at a rate of 1.5cm a year and while that might not seem as dramatic as Jakarta's situation, the sea level in the Bay of Bengal is rising 10 times faster than the global average.

Millions in the city's coastal areas have already fled, migrating to Dhaka's overcrowded slums. Like Jakarta, the situation is being exacerbated by groundwater extraction at an unsustainable rate, as well as shifting tectonic plates.