Urbanization comes with a cost. A huge cost, perhaps.

China is presenting a grim picture. How?

Nearly half of China’s major cities are sinking because of water extraction and the increasing weight of rapid expansion, the latest BBC reports say.

Scientists blame the new cause for worry is because China is rapidly expanding. 

Some cities in the country are sinking rapidly, with one in six exceeding 10mm a year. 

Other major urban centers in Asia, including Osaka and Tokyo in Japan, also face the issue of subsidence. 

What does the future hold for people living in urban cities, then? 

If this trend continues unchecked, the people, especially those living in the coastal regions, are threatened with flash flooding as the sea level (alarmingly) rises every year. 

Shanghai in China has sunk more than 3mm in the past century.

A team of researchers from several Chinese universities observed the period between 2015 and 2022 using data from Sentinel – 1 satellites. 

They found 45% of urban areas are subsiding (sinking) by more than 3mm per year.

The scientists say that around 16% of urban land is sinking faster than 10mm a year. They say it’s a rapid descent.

That means a whopping 67 million people are currently living (at risk) on this fast disappearing stretch of land. 

What influences the scale of decline? 

The soil, the weight of buildings and, to a major extent, the extraction of groundwater water determine the decline.

This pattern is noticeable in several major urban areas around the world now, including Houston, Mexico City and Delhi.

“I think water extraction is, to my mind, probably the dominant reason,” said Prof Robert Nicholls, from the University of East Anglia.

The other major cause of worry is urban transportation systems and uncontrolled mining for minerals and coal.

The researchers say hundreds of millions of people are at the risk of flooding as the land is sinking faster than the sea level rising. The latter because of climate change, as you know.

Gone are the days when people in the 1970s used piped water and were less dependent on bore-wells. 

It’s time the authorities sat and enacted a law that makes it illegal to extract water (unscrupulously) from the ground.

Will they do? 

Because that might help save the ground fast disappearing under our feet and help save a million people living in the coastal regions.