• Adika Witoelar

Jakarta Sinking


The global sea level has risen, on average, by 3.6 millimeters per year from 2006-2015, more than double the average rate of 1.4 millimeters per year for most of the twentieth century. The current ocean level in 2021 sits at about 99 millimeters. The number itself might seem trivial, and we might think that it’s not a big deal that the ocean is increasing in such a minuscule amount, yet the reality is that it is much worse than most people expect. A staggering amount of people — more than 600 million — live in coastal areas that are less than ten meters above sea level, and rising sea levels present a clear danger to them in areas such as food production (i.e. fisheries), trade, and even health. There are two main causes of sea-level rise: changes in the volume of water due to the recent increase in the melting of glaciers, and the warming of water, which causes the deep ocean to expand ever so slightly. Moreover, there are location-specific factors that can also worsen the effects of sea-level rise — one such location that needs to be focused on is Jakarta — the capital city of the world’s largest archipelago, Indonesia.

Below are pictures of Northern Jakarta and Jakarta Bay. We can observe that since 1990, a huge part of the coastline has been engulfed by water.

Pictured in 1990.

Pictured in 2019.

Jakarta and its surrounding metropolitan area (Jabodetabek) represent the second most populous cities globally, with a population just above 30 million. The rising sea level has been tough on the millions of citizens living near its low-lying rivers and coastal areas. Major devastating floods due to more frequent rainstorms and poor infrastructure have caused displacement and hundreds of millions of dollars in property damages — one such case of a damaging flood happened back in 2013, wherein the Central Business District and governmental agencies were forced to close as the flood inundated roads and adversely impacted roughly a quarter-million people. In total the flood caused at least 490 million USD in losses, begging the question: Why is Jakarta suffering so much from trends in sea-level rise?

Though Jakarta experiences the same average sea-level rise as other coastline cities in the world, it is particularly vulnerable because unprecedented groundwater extraction and rapid development and urbanization contribute to the topographic phenomenon of land subsidence. Groundwater extraction through wells and pumps essentially depletes the city’s aquifers, causing the land to sink further and at a much higher rate than before. This particular method of acquiring water is used by about half of Jakarta’s residents, primarily for drinking water and toilet use. Demand for water has been rising in recent decades due to massive population growth and has made groundwater extraction much more popular; additionally, the alternative method of piped water is still limited to the smaller population of Jakarta citizens that live more inland (and are frankly richer). On top of that, the people that generally utilize groundwater extraction do not have the privilege or means to move to a better area that does have piped water, forcing them to use this method. Jakarta is developing fast and at such a monumental scale, yet it fails to take into account the unequal and harmful nature of its water infrastructure.

A seawall separating the sea and an urban village in Jakarta.

An additional reason for land subsidence getting increasingly worse is rapid development and poor infrastructure planning in northern parts of Jakarta and around Jakarta Bay. Groundwater usually replenishes with rainwater, and Jakarta — with 300 days of rain and 13 rivers flowing through the city — has no problem regarding freshwater sources. Unfortunately, Jakarta’s marshlands and wetlands (especially in the Northern areas) have been mostly paved over and filled in with buildings, shopping malls, offices, hotels, and apartments by prominent real-estate developers, which leads to freshwater not being retained by the ground and unable to drain out to the sea. As a result, storm surges and heavy rainfall can and often do cause catastrophic floods.

Time is of the essence when it comes to creating solutions that are both effective and green. There are some solutions already taking place and fortunately some great ideas to be implemented in the near future. One such solution, which actually might not be as effective as the government thought, is building giant sea walls around certain areas prone to flooding. One wall located at the Muara Angke urban village stretches eight kilometers and was once high enough to protect residents from rising sea levels. As the years go by, the village has become increasingly prone to frequent flooding from rainwater trapped within; yet at the same time, the wall will need to be built higher as the sea level keeps continues rising. It is estimated, however, that doing this repeatedly and investing in a giant sea wall around the city would cost about 42 billion dollars.

A more sustainable example would be controlling waterways and closing down illegal wells while simultaneously creating infiltration wells: Artificial systems that absorb water into the ground, whether it be rainwater, water from ablution, or other types of wastewater. Another would be to clean river pollution, as it clogs up the waterways necessary for freshwater to drain to the ocean — this has proven though to be quite labor-intensive. A current proposed solution is to reduce the amount of groundwater extraction in general, either by taxing groundwater consumption, developing alternative water supplies, or relocating groundwater users outside of critical zones. Nonetheless, this solution could be controversial as it forces a burden upon citizens who do not have the privilege of good water infrastructure in the first place.

The situation in Jakarta has so far sounded bleak, and the complex problem of climate change, sea-level rise, and groundwater-related subsistence in the Northern areas of Jakarta seem impossible to solve. Although the present and proposed solutions are far from perfect and at times ineffective and unsustainable, we can still be hopeful. The much-needed publicity directed towards this problem has been positive, as it raises awareness among the city’s own citizens and government. Public schools are even starting to incorporate environmental science within their curriculums! Citizens of the city have become much more environmentally aware over the past few years regarding the framework of the problem. It is important to utilize this awareness as a momentum to keep pressuring the governments and corporations to collaborate and brainstorm sustainable solutions, as the longer we keep delaying action, the faster the city will sink.

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