Portside

This week, amid devastating flooding, Indonesia announced it's planning to move its capital out of Jakarta, which really is nothing new—the country’s first president was talking about it way back in 1957. Part of the problem is extreme congestion, but today the city of more than 10 million is facing nothing short of obliteration by rising seas and sinking land, two opposing yet complementary forces of doom. Models predict that by 2050, 95 percent of North Jakarta could be submerged. And Jakarta is far from alone—cities the world over are drowning and sinking, and there’s very little we can do about it short of stopping climate change entirely.

Jakarta is a victim of climate change, the fault of humans the world over (though mostly the fault of corporations), but it’s also a victim of its own policies. The city is sinking—a process known as land subsidence—because residents and industries have been draining aquifers, often illegally, to the point that the land is now collapsing. Think of it like a giant underground water bottle: If you empty too much of it and give it a good squeeze, it’s going to buckle. Accordingly, parts of Jakarta are sinking by as much as 10 inches a year.

That’s destabilizing buildings in the short term—some structures have sunk straight down, enveloping their lower levels in mud—but in the long term it means that about half the city is now beneath sea level. All it takes is one storm surge to inundate a huge chunk of the metropolis: In 2007, for instance, a monsoon left half of Jakarta under as much as 13 feet of water, causing more than half a billion dollars in damage.

Jakarta’s situation may be particularly dire, but it isn’t the only coastal metropolis that’s sinking. “Almost every coastal city around the world builds on loose sediment, and all of them are subsiding, regardless of pumping groundwater,” says Arizona State University geophysicist Manoochehr Shirzaei, who studies land subsidence. “In fact, vertical land motion is as important as sea level rise, but unfortunately it gets very little attention, because the process is slow.”

Consider the San Francisco Bay Area. Last year, Shirzaei published a study that showed most of its coastline is sinking around .07 inches a year, not because of groundwater drainage but because of the natural settling of soils or landfill. That’s tiny compared to Jakarta’s 10 inches of annual sinkage, sure. (And well short of Mexico City, perhaps the fastest-sinking place on Earth, at a foot a year. Also notable: California’s Central Valley, which has sunk almost 30 feet in places due to groundwater overexploitation.) But that adds up over time—the analysis estimated that the San Francisco airport could be underwater by 2100.

That’s an inevitable consequence of building on landfill, but Jakarta has the power to cut back on the groundwater pumping that’s the root of the crisis. Except, even that won’t save the day. “This has been happening for so long, that when you remove water from the ground the porous structure collapses,” says University of Oregon earth scientist Estelle Chaussard, who’s studied land subsidence in Jakarta. “The problem is that a large amount of this subsidence, and this decrease in porous storage of the aquifer, is irreversible.” Not only that, layers of the porous earth will keep deforming even if you stop pumping groundwater, potentially causing further subsidence, though at least a smaller amount of it.

Even if Jakarta could stop land subsidence, it’s still sitting on the edge of the sea, and seas are rising. The city has already deployed a network of canals and seawalls to stave off the threat, but with climate change the threat will only grow worse.

It is, in short, the makings of a humanitarian crisis, not just in Jakarta but around the globe. Those who can afford to move away from sinking and flooding coastal cities will find comfort elsewhere while the poor drown. Sewage will fill the streets, bringing disease. Physical health will fail, but so too will mental health, which no one wants to talk about under normal circumstances and even less so in the context of climate change.

What policymakers do have, however, is better data with which to face the future. Satellites can see with increasing granularity how coastlines are transforming. The spacecraft do this by firing radar signals at the Earth to determine in fine detail how fast the land is moving either toward the satellite or away from it. “It a tremendous resource, not just to identify the longer-term rates of change, but also you can see seasonal variability,” says USGS coastal geologist Patrick Barnard. “Like when the aquifer is recharged in the winter, you can actually see the ground swelling, and when it's more depleted in the summer, you can see it subsiding.”

This kind of data can help inform, for example, which areas of land are becoming too risky to support human life, given the threat of storm surges. “Now we have a better understanding of how we can affect the motion of the land,” says Barnard. “It's not just the ocean, and it's not just the land—they have to be considered together.”

Meanwhile, the population needs to drink: Only a quarter of Jakarta’s people are hooked up to a piped water system. The rest either get their water from their own wells or buy it from vendors, who also pull from wells. The temptation might be to switch over to desalination to quench Jakarta’s thirst, as Israel has done to produce more freshwater than it needs. But it’s not so simple. “You could desalinate until you're blue in the face and you won't be able to fill the void,” says Michael Kiparsky, director of the Wheeler Water Institute at UC Berkeley. “The scale of water use in Jakarta is immense, and the cost of the infrastructure and the cost of the energy to desalinate the ocean water would be massive.”

“The message here is that technology can't get us out of this,” Kiparsky adds. “You need something more difficult—you need institutional solutions, you need political will to do something radical.”

In this case, one radical solution might indeed be moving the capital to less compromised ground. As for where New Jakarta will rise, or when, the Indonesian government has given almost zero details. Meanwhile, the sea will gnaw ever more violently at one of the great metropolises of the world.