Facing the sinking cities in the midst of climate change

Jakarta, Hanoi, Kobe, and Houston are 4 out of the ten fastest-sinking cities in the world[1]. The problem is aggravated by climate change, which causes coastal cities to face massive flooding as sea levels rise. Certain districts of Jakarta, especially near Jakarta Bay, have sunk more than 4 meters since the 1970s, directly resulting from excessive and uncontrolled groundwater use[2]. Besides excessive groundwater extraction, rapid urbanization and population growth are major causes of severe land subsidence[3]. In urban areas, residential areas such as multi-story apartments, landed houses in real estate, and informal settlements are primary drivers for land subsidence due to the massive groundwater use. In some countries, government regulation in groundwater use is fully enforced, and the water piping systems are in place, so groundwater use is under control. But for informal settlements and slums, the condition is different. Over 1 billion people live in slums and informal settlements across the Global South without formal access to potable water, sewage, or electricity[4]. Therefore, it is urgent to support the people in that settlement so they can reduce groundwater use significantly.

Several housing programs have already been launched, such as repair, seismic retrofitting, and other home improvement programs. Due to this urgency, the program should be redesigned to incorporate access to potable water and reduce electricity use. The difference with the current home improvement program is that the new support should cover all inhabitants within the area. For instance, the seismic retrofitting and house improvement program is carried out only for the selected household that falls into the program category, such as those who fall into vulnerable criteria and live in a house that is vulnerable to hazards.

Challenges in the current program are on the demand side. For instance, even seismic retrofitting is crucial to have earthquake-resistant houses; only a few people are willing to retrofit them. They do not prioritize the initiative primarily because of the cost, and earthquake events do not happen regularly. People will raise their house level, even if expensive, since they realize that floods or rising water levels always occur. If it happens, it is already too late.

Hence, facing the sinking problem, adapting to climate change, and having resilient houses should be supported by various agencies since they will be integrated across sectors and carried out simultaneously. Housing actors can provide technical assistance in having robust houses that abide by the building code. Moreover, the provision of design that might reduce energy consumption and use low-power electronics should be introduced. Municipalities and water agencies provide water systems to cover the needs of all households in the area. Once all are in place, policy on the prevention of groundwater use should be enforced. Educating the community on how to use water wisely should be done continuously. However, the most important is improving their livelihood; all tend to fail if they live in poverty. Informal settlements in coastal towns should be prioritized to have this assistance very soon.

Arwin Soelaksono 

Photo: Artistpix/Shutterstock

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[1] Squires. C, These are the 10 fastest sinking cities in the world. World Economic Forum. 2022. https://www.weforum.org/agenda/2022/04/coastal-cities-flooding-sinking-climate-change/

[2] Walton, B. Indonesia: As seas rise, unchecked groundwater use sinks coastal cities. PreventionWeb. 2019. https://www.preventionweb.net/news/indonesia-seas-rise-unchecked-groundwater-use-sinks-coastal-cities  

[3] Erkens, G. et al. Sinking coastal cities. 2015. doi:10.5194/piahs-372-189-2015

[4] GSG. Informal Settlements: No Longer Invisible. The role of impact in scaling capital mobilization to fund slum-upgrading programs globally. 2022