Chinese Cities Are Sinking Into the Earth, Scientists Find

This is bad.

Sinking Feeling

A new study has discovered that a staggering number of Chinese cities are sinking into the Earth.

According to the study, which was conducted by a team of over 50 Chinese scientists using radar observations and published this week in the journal Science, almost half of China's 82 major cities are experiencing rapid subsidence.

Subsidence, or the scientific term for the Earth's surface effectively sinking in on itself, is a serious issue. Not only does it present obvious infrastructure and safety dangers, but as NPR notes, sinking land is also known to expedite the problem of already-rising coastlines. And by these researchers' estimates, the extreme sinking observed in China could mean that about a quarter of the nation's coastal regions are below sea level by the year 2120.

Combine the problem of sinking cities with China's massive population, and as the researchers point out in their study, you have a recipe for a human and infrastructural disaster.

"Even a small portion of subsiding land in China," the researchers write, "could therefore translate into a substantial threat to urban life."

Global concern

Subsidence isn't just a problem in China. Countries worldwide are experiencing a concerning level of land sink, and in January, a satellite-based study revealed that US' major East Coast population centers are similarly caving into the Earth, as are gulf cities like New Orleans and Houston.

"This is a big problem," Robert Nicholls, a professor of climate adaptation at the University of East Anglia in England who wasn't involved with the study, told NPR. "The scale is large."

"Without doubt," he added, this new study "brings home that this is not a local problem. This is a national, or even international, problem."

But while land sinking is an international problem, cities in Asia might be uniquely at risk. As Nicholls reportedly told NPR, Asian cities are commonly constructed on river deltas, which are particularly susceptible to subsidence. The Indonesian capital city of Jakarta, for example, was built on a river delta and is sinking beneath sea level at a deeply alarming rate.

In short, subsidence is a growing threat. And while mitigating subsidence is a complicated fix, this latest study highlights just how important those mitigation efforts might just be for protecting land for future generations.

"Our results underscore the necessity of enhancing protective measures," the researchers write, "to mitigate potential damages from subsidence."

More on subsidence: Satellites Show the East Coast Is Sinking