In the next few years, Indonesia will start moving its capital city from one island, Java, to another, Kalimantan, the Indonesian part of Borneo. There are a few reasons for the move, but one of the biggest is that the country’s current capital, Jakarta, is sinking at an alarming rate. By the middle of this century, one-third of the city will be underwater.

It would be easy to mistake Jakarta’s pending demise as the work of sea level rise. Yet the city’s decline is actually being driven by another force — land subsidence spurred by groundwater extraction.

Projections of sea level rise have put a countdown on several coastal cities. But a new study shows that the combination of coastal subsidence and sea level rise acts like a welcome mat for water. Using satellite data, the researchers measured subsidence rates in 99 coastal cities around the world. They found that most are sinking faster than sea levels are rising. In many cities, such as Manila in the Philippines, Tampa in Florida, and Alexandria in Egypt, this means coastal flooding will become an issue much sooner than predicted by models of sea level rise alone.

The worst affected cities are all in Asia. These cities, including Chattogram in Bangladesh, Semarang in Indonesia, and Ho Chi Minh City in Vietnam, have areas with subsidence rates of more than 20 millimeters per year, which is 10 times higher than the global mean sea level rise of two millimeters per year. In one-third of the 99 cities studied, however, at least part of the city is sinking by 10 millimeters or more per year.

Read the full article about coastal cities by Michael Allen at Grist.