Half of China’s largest cities are sinking – Researchers

Almost half of China’s big cities are sinking into the ground, which could cause flooding for millions of people as the sea levels rise. This information comes from a study that looked at satellite data from all over the country.

The researchers who wrote the article in the journal Science discovered that 45% of China’s cities are sinking at a rate of more than 3 millimeters per year, and 16% are sinking at a rate of more than 10 mm per year. This is happening because the water levels are going down and the weight of the buildings is pushing the land down.

“China has a lot of people living in cities, over 900 million. If the land starts sinking, it could be a big problem for the cities,” said the researchers.

Sinking land in China is causing big problems and costs a lot of money every year. In the next 100 years, about a quarter of the land near the coast could be lower than the sea, putting many people at risk of flooding. This could affect hundreds of millions of people.

“Robert Nicholls at the Tyndall Centre for Climate Change Research at the University of East Anglia said it shows that this is a problem for all of China, not just a few places. ” “And it represents what is happening in the rest of the world in a small way. ”

Tianjin, a city in the north with over 15 million people, was one of the hardest hit. 3,000 people had to leave their homes because of a sudden earth disaster. Investigators said it happened because there wasn’t enough water and because people had been building geothermal wells.

A lot of China’s old coal areas have been damaged because there was too much mining. Sometimes, officials have to put concrete into the falling apart holes in the ground to make the land stronger.

The problem is not just in China. Another research published in February found that about 6. 3 million square kilometers of land around the world could be in danger. Indonesia is one of the countries that has been hit the hardest, with many areas of the capital city Jakarta now underwater.

Nicholls said cities that are at risk could learn from Tokyo’s example. Tokyo used to sink by about 5 meters until it stopped taking water from the ground in the 1970s.

“We need to take subsidence seriously, but we can’t prevent all of it. So, we should also focus on adapting and building dykes,” he said.

In a study from Singapore in 2022, it was found that out of 44 big cities by the coast with a problem, 30 of them were in Asia.

Matt Wei, who is an expert in studying the Earth, said that when more people move to cities and the population grows, there is a bigger demand for water. This can cause the ground to sink.