Indonesia made a stunning announcement last week that it will relocate its capital from Jakarta. The decision validates decades of warnings about the city's catastrophic flood risk due to sinking land and rising seas. While Jakarta is especially vulnerable to the threat of rising seas, it serves as a profound wake-up call for hundreds of major cities, Washington included.

In making his decision, Indonesian President Joko Widodo said the move is necessary, given that the city can no longer support its massive population in the face of environmental threats, as well as concerns of traffic congestion and water shortages. Surely at the top of his concerns is the fact that the city is sinking, a phenomenon known as subsidence. In the past 30 years, Jakarta sank more than 3m - a problem made only worse as the world's great ice sheets melt.