PerspectiveJakarta’s Giant Sea Wall Is Useless If the City Keeps Sinking

Published 31 July 2019

Late last week, president Joko Widodo of Indonesia told the AP that he’s fast-tracking a decade-in-the-making plan for a giant sea wall around Jakarta, a city that’s sinking as much as 8 inches a year in places—and as seas rise, no less. Models predict that by 2050, a third of the city could be submerged. It’s an urban existential crisis the likes of which the modern world has never seen.

Late last week, president Joko Widodo of Indonesia told the AP that he’s fast-tracking a decade-in-the-making plan for a giant sea wall around Jakarta, a city that’s sinking as much as 8 inches a year in places—and as seas rise, no less. Models predict that by 2050, a third of the city could be submerged. It’s an urban existential crisis the likes of which the modern world has never seen.

Matt Simon writes in Wired that deploying a sea wall, however, is a massive political and engineering problem in any country, to say nothing of Indonesia’s struggles with a literal underlying crisis: Jakarta’s people are pumping too much groundwater, and consequently the land is collapsing underneath them. If Jakarta can’t find a way to hydrate its people some other way, it’ll keep sinking, pulling that new sea wall down with it. It’s a glimpse of a dark future for much of human civilization, which stubbornly clings to coasts around the world.

Think of Jakarta as sitting on top of giant water bottles, aka aquifers. Forty percent of its 10 million residents get their water from pumping, so they’ve been draining those bottles, which consequently collapse, leading to land subsidence. This, by the way, is not unique to Jakarta: California’s Central Valley has sunk by as much as 30 feet for the same reason. But because other nations have dealt with the problem, Jakarta knows how to fix it.