Rising sea levels are a growing worry for many coastal cities around the world. While all are expected to be impacted, some like Indonesia's capital Jakarta, are more vulnerable. Located in the northwest coast of the Java Sea, Southeast Asia's most populous city lies on a low flat basin at the mouth of the Ciliwung River on the Jakarta Bay. Though its average elevation is 8-meters (26 feet), 40% of the city lies below sea level and is sinking by as much as six inches, annually. Experts speculate that if this pace continues, much of northern Jakarta will be underwater by 2030.