Explained: Why Indonesia's Jakarta Is The Fastest Sinking City In The World

Jakarta, one of the world's most heavily occupied cities, is sinking and has been vanishing into the ground for decades now. According to specialists at the Bandung Institute of Technology, over 95 percent of North Jakarta will be drowned by 2050.

Current situation

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North Jakarta has fallen 2.5 metres in ten years and is still sinking at a rate of up to 25 centimetres annually in some areas, and over twice the global average for coastal megacities. Jakarta is sliding at a rate of 1-15cm each year, according to media reports, and nearly half of the state is currently under sea level.

Not only the north, but the remainder of Jakarta is also sinking, although at a moderate pace. According to the report, the land in West Jakarta is dropping by as much as 15cm every year, 10cm in the east, 2 cm in Central Jakarta, and only 1cm in South Jakarta.

Climate change

According to experts, climate change is expected to raise the risk by double, perhaps more. Changing climate has melted 3 glacial zones on Earth, according to reports: Antarctica in the southern polar areas, Greenland in the north, and the Mountain range in the north. As a consequence, sea levels have risen and seas have extended, placing coastal communities at risk of drowning.

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The issues of rising water are exacerbated by strong surges, cyclones, and waves brought on by climate change. Furthermore, Jakarta is frequently flooded as a result of severe rains from upstream or local rains.

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It has been regarded as the world's fastest sinking metropolis, with one-third of the city expected to be inundated by 2050 if current trends continue. Uncontrolled groundwater exploitation is the primary cause, which has been compounded by the expanding Java Sea as a result of climate change.

Sinking land due to drinking water

According to the World Economic Forum, it is among the world 's rapidly vanishing cities. About half of the town is now submerged.

The major cause of the city's sinking is a lack of enough water for the majority of the population. The town does not lack freshwater; it receives 300 days of rain per year and has thirteen rivers flowing through it. The issue is that this water is not maintained since regions that were formerly marshlands with mangroves have been covered in and built over to make way for retail malls, office and apartment buildings. Jakarta's wetlands have been converted to concrete jungle to the tune of 97 percent.

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"There are no green spots left in Jakarta. Rather than concrete areas, we need more woodland and wetlands" Dicky Edwin Hindarto, a climate expert based in Jakarta, told Mongabay.

People are pushed to draw water from aquifers as piped water is unreliable, irregular, and expensive. The pumps go deep in the earth to draw water from aquifers, which are subsurface rock strata that retain groundwater. It seeps into the porous spaces of the rock.

Excess groundwater use leads the ground above it to fall, resulting in land subsidence, a phenomenon in which rock and silt pile up on top of one another.

The longer water extracted, the more it diminishes, compacting and collapsing the soil and sinking the earth above it. Pumps on their own will not be equipped to accomplish this. Although some levels of the earth would never regain their water, aquifers are normally restored naturally whenever it rains, according to experts.

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However, this is becoming increasingly rare in Jakarta. Jakarta has been rapidly rising for years and is now completely encased in concrete. As a result, rainwater that would normally fill the aquifers is not absorbed. It's grown so severe that residents in coastal locations prone to flooding, such as the fishing village of Muara Baru, have created temporary bridges to get around.

According to a Reuters report, the Jakarta administration does not even disclose records on groundwater use quantity. In 2014, Governor Basuki Tjajaja Purnama stated that unlawful use of aquifers had reached dangerous proportions. The Ministry of Environment's 2009 regulation to restore the water sources failed due to a lack of enforcement mechanisms. According to the decree, householders and commercial buildings were compelled to soak and retain rainwater on their premises in 3-foot-deep biopore cylinders.

Floodwaters during high tide and rainy seasons have become much more deadly as a result of this, especially in combination with sea level rise. Such as in 2007, when one of the greatest floods in Jakarta's modern history struck.

Climate change

Coastal areas are being impacted by sea level rise as a result of global warming. Thermal expansion (water rising due to extra heat) and polar ice melting are two factors that contribute to rising sea levels, according to a BBC report.

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The water level is increasing and the north shore of Java is sinking. According to sources, Demak Regency, which contains Timbul Sloko, is one of the hardest devastated areas along the coast. While water levels around the globe are rising about an eighth of an inch per year as a result of global warming, the ground here is sinking as much as four inches per year. Every year, the Java Sea takes about a thousand acres of land from Demak, accounting for roughly half of its total area.

The impacts are exacerbated by the fact that all of the difficulties are present. Environmental disruption will make supplies more erratic as the urban population grows, increasing water requirements. This will expand groundwater exploitation even more.

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Mangroves should be reintroduced, and ponds that were formerly part of old Jakarta should be rejuvenated, according to experts. Since 2011, the Indonesian administration claims to have planted over three million mangroves throughout Central Java, encompassing 900 acres, to absorb the force of the waves and tides. By 2023, the goal is to cover about 2,000 acres.

Poor planning

According to a media report, economic growth has aggravated the impacts of the sinking. When settlements tend to grow near low-lying regions, the effect of deflation, which is mostly caused by groundwater extraction, is magnified. According to the same report, the number of households in risky coastline regions of Indonesia was 47.2 million in 2010, making it one of the largest in the world and up 35% since 1990.

Without sufficient groundwater recharge, unchecked urbanisation can have disastrous consequences. The events of flooding in Chennai, Tamil Nadu, in 2015 were an outcome of this.

Solutions to increase resiliency

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The Jakarta municipality has sought to minimize major customers' groundwater consumption to decrease the impact of the principal source of land subsidence. However, there really is no other source of water. According to reports, the local Jakarta administration is still unable to deliver water for domestic use to the city's 9 million residents and another 15 million people who work and travel in the city during the day.

As a precaution to defend the town from the storm of seawater, the National Capital Integrated Coastal Development Programme is also underway. It also entails the construction of a massive seawall.

And, in order to relieve the pressure on Jakarta, Indonesian President Joko Widodo stated that the nation's capital will be relocated from Java's heartland to East Kalimantan, on Borneo's forest region. The main factors highlighted by Widodo were Jakarta's growing pollution and overpopulation.

"The site is really important - it's in the centre of Indonesia and adjacent to urban regions," Widodo said in a speech in 2019, according to The Guardian.

Jakarta's load as a centre of administration, commerce, economics, trade, and services is currently too high."

A look at some other rapidly sinking cities

Houston has been sinking for years now, and even here exploitation of groundwater is partly responsible, as it is in Indonesia. According to statistics from the US Geological Survey, sections of Harris County, which includes Houston, have fallen from 10 and 12 feet (about 3 metres) since the 1920s, reports the Houston Chronicle.

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Likewise, Lagos, Nigeria 's largest metropolis, is built partially on the mainland and partly on several neighbouring islands. It is also the most populated city in Africa. Lagos' topography makes it particularly vulnerable to flooding, and the coastline is already deteriorating. The city is becoming increasingly vulnerable as sea levels rise as a result of global change.

As Nigeria's shoreline is so flat, a sea level rise of merely 3 to 9 feet (approximately 1 to 3 metres) would "have a disastrous impact on people's activity in these places," according to a 2012 research.

A 2016 research highlighted that Beijing is sinking by as much as 4 inches (10 cm) annually in some locations. The reason for the subsidence, according to researchers, was a lack of water, similar to the scenario in Indonesia and Houston.

Beijing, as a non-coastal metropolis, is primarily reliant on groundwater as a flow of clean water. The water had been gathering for years, but its removal had dried up the soil and caused it to compress, causing it to sink.

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