Over a third of urban Chinese live in sinking cities

Across the world, many cities are slowly sinking. Most are on the coast, including tropical megacities like Jakarta in Indonesia or Manila in the Philippines, or places like New Orleans, Vancouver or much of the Netherlands. Other sinking cities, like Mexico City and many of those in China, can be well inland. Yet this still remains a widely overlooked hazard.

In my three decades assessing this topic, I have reviewed evidence of subsidence in cities around the world. The problem is especially significant in Asia, where about 60% of the world’s population lives and the cities are growing rapidly. However, some cities have also shown there are things that can be done to stop subsidence.

The problem is illustrated by a recent study by researchers in China which found more than a third of the country’s urban population – some 270 million people – living in sinking cities.

The authors analyzed satellite-derived data from 2015 to 2022 across China’s 82 most important cities to produce accurate and consistent maps of vertical land movement. Consistently measuring subsidence in all these cities, with a collective population of nearly 700 million people, is a great achievement.

They found that 37 of the 82 cities they looked at are sinking, and nearly 70 million people are experiencing rapid subsidence of 10mm a year or more. This may not sound much but the subsidence accumulates over time and can damage infrastructure and buildings, and make floods more dangerous.

Where China’s sinking cities are found:

There are a number of sinking hotspots in China mainly in the east of the country, especially near the coast. These include the inland capital Beijing and the nearby (London-sized) port city of Tianjin.

Why cities sink

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