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What do Venice, Jakarta, Manilla and Bangkok have in common? They are or were sinking cities. Wageningen researcher Philip Minderhoud studies the causes of subsidence in these cities. Groundwater extraction plays an important part in all cases. The good news is that this can be avoided.

The best-known example of a sinking city is Jakarta. Large sections of the Indonesian city have dropped by three to four meters since the '80s, and continue to do so by up to ten centimeters annually. Some 40% of the city is below sea level, prompting the Indonesian government to move the capital to Kalimantan.

Sinking cities are mainly the result of groundwater extraction, says Minderhoud. Tragically, in the case of Jakarta, this cause has been ignored for many years.

"A professor of tectonics in Jakarta claimed that subterranean tectonic shifts were causing the subsidence. This may, indeed, cause subsidence, but the effect of groundwater extraction was not sufficiently considered," Minderhoud notes.

The fact that water extraction delivers clean drinking water and drives economic development, and as such, benefits many may have contributed, says Minderhoud. "Although it is technically simple to stop extracting groundwater, doing so is a socioeconomic challenge."

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