We’d like to think that coastal cities can build their way out of flooding and sea level rise. Maybe it’s even theoretically true, from an engineering standpoint. But in Indonesia’s capital, GroundTruth fellow Chris Bentley finds out that extreme measures to adapt – like mass evictions along Jakarta’s rivers – can be as damaging and disruptive as the effects of climate change itself.
Behind the Science
Jakarta is a low-lying coastal city where nearly half of the population currently lives below sea level. The city has three big problems with water. First and foremost, the city is sinking. As Jakartans pump out groundwater beneath their feet, they’re causing what geologists call land subsidence. Parts of Jakarta, including the seaside area of Pluit, are sinking nearly 8 inches each year. The city is growing, and the problem is getting worse – the local water authority estimates illegal groundwater pumping has increased tenfold in recent years.
Land subsidence is not climate change. But it is exacerbating Jakarta’s other two problems with water, which are getting worse thanks to global warming.
Like most coastal cities, Jakarta is also threatened by sea level rise. As the global average temperature of the Earth rises due to the greenhouse effect, the oceans are getting bigger. This happens through a combination of thermal expansion (water expands when it’s warmed up) and the melting of ice sheets mainly in the Arctic, Greenland and Antarctica. Global sea levels have already risen about 8 inches since 1880, and the rate of sea level rise is accelerating. How much more sea level rise will occur is still hotly debated, but climate scientists predict between 2 and 7 feet by the year 2100.
Jakarta’s third problem is rain and riverine flooding. Thirteen rivers flow through the Jakarta metropolitan area, collecting rain and runoff as they meander down from the mountains to the south of the city on their way to the Java Sea. Globally, climate change is expected to supercharge storm systems because air can hold more moisture at higher temperatures. In any given area, this could lead to an overall increase in rainfall, an increase in droughts, or an increase in the number of extreme storms. In Jakarta it is increasing rainfall and making the region’s monsoon climate more extreme. Land subsidence also makes things worse here because Jakarta’s rivers are sinking along with the city, making it easier for rainfall and runoff to pool up in Jakarta instead of draining quickly to the sea.
The combination of sea level rise, extreme precipitation events and runaway land subsidence has put Jakarta in an extreme situation: If nothing is done, this city of nearly 10 million could be underwater by 2050.
Credits
- Managing producer: Rachel Rohr
- Consulting editor: Nathan Tobey
- Health & environment editor: Marissa Miley
- Sound designer: Robert Andersson
- Executive editor: Charles Sennott
Special thanks to Tom Devlin, Phil Redo, Bob Kempf and Doug Shugarts at WGBH.
