For the best experienceDownload the Mobile App
App Store Play Store
China’s cities are sinking, putting tens of millions at risk
China’s cities are sinking, putting tens of millions at risk
China’s cities are sinking, putting tens of millions at risk

Published on: 04/18/2024

This news was posted by Oregon Today News

Go To Business Place

Description

Nearly half of the major cities in China are sinking, a new study finds. Subsidence exacerbates flooding related to sea level rise from climate change. Parts of Shanghai have subsided up to 9 feet in the last century.

Major cities across China are sinking, putting a substantial portion of the country's rapidly urbanizing population in harm's way in the coming decades, according to a sweeping new analysis by Chinese scientists.

Subsidence is the technical term for when land sinks relative to its surroundings, and it's a major threat for cities around the world. It accelerates local sea level rise from climate change, because the land is getting lower as the ocean gets higher. Urban subsidence can also affect inland cities by damaging buildings and roads, and causing drainage issues when water is trapped in sinking areas.

Out of 82 major Chinese cities, nearly half are measurably subsiding, according to the new study, which was published in the journal Science and conducted by more than 50 scientists at Chinese research institutes. The areas that are sinking are home to nearly one third of China's urban population. And the authors estimate that about a quarter of China's coastal land will be below sea level in the next hundred years, largely due to subsidence.

That means tens of millions of people are already at risk, and that could grow to hundreds of millions if China's cities continue to both grow in population and subside at their current rate, and seas continue to rise. Oceans are rising steadily due to greenhouse gas emissions from burning oil, gas and coal.

"This is a big problem," says Robert Nicholls, a subsidence expert at the University of East Anglia in England who was not involved in the study. "The scale is large. Without doubt, it brings home that this is not a local problem. This is a national, or even international, problem."

This is the first time scientists have used satellite data to systematically measure how much cities are sinking across China. The study measured how much cities subsided between 2015 and 2022. Similar recent studies in Europe and the United States have also found significant subsidence in some cities, but didn't show the same widespread sinking that is present across China.

"The places that really have high levels of subsidence are Asia," says Nicholls, who was one of the authors of a recent study that analyzed sinking cities across the U.S. Asia is at higher risk, he says, because many Asian cities are built on river deltas that are prone to sinking when you put heavy buildings on top and pump groundwater out from below. The places that are sinking most rapidly in the U.S., such as New Orleans, share that geology.

Measuring how much cities are sinking can help urban planners and government officials prevent future subsidence and even reverse some sinking that has already occurred. In places where groundwater removal is the main problem, cities can ban further pumping of groundwater from areas that are rapidly sinking. In some cases, it's even possible to pump water back into the ground to prop up land that had fallen.

For example, parts of Tokyo subsided a jaw-dropping 15 feet in the twentieth century, says Nicholls, but managed to stabilize the lowest parts of the city by enforcing strict groundwater rules.

And understanding which parts of a city are sinking the most – and why – can help urban planners make better decisions about where to build heavy buildings, and how to protect buildings from future flooding. Teasing apart those local questions will require deeper, city-by-city studies in the future.

Copyright 2024 NPR. To see more, visit https://www.npr.org.

News Source : https://www.opb.org/article/2024/04/18/china-s-cities-are-sinking-putting-tens-of-millions-at-risk/

Other Related News

Pro-Palestinian protest encampment at the University of Oregon nearly triples in size
Pro-Palestinian protest encampment at the University of Oregon nearly triples in size

05/02/2024

Students at the University of Oregon have set up a pro-Palestinian protest camp outside of...

Lightning caused wildfire south of Bend encouraged to grow
Lightning caused wildfire south of Bend encouraged to grow

05/02/2024

Sometimes lightning caused fires are a good thing in forests that will benefit from a low ...

New study shows Oregon not prepared for disaster
New study shows Oregon not prepared for disaster

05/02/2024

Here are some tips on how to prepare for wildfires earthquakes and droughts

Dear Abby: Husband accidentally discovers his wife has been cheating on him for 10 years
Dear Abby: Husband accidentally discovers his wife has been cheating on him for 10 years

05/02/2024

DEAR ABBY After 10 years of being with my wife including eight years of marriage I acciden...

Ask Amy: Husband doesn’t feel right after wife’s sister drops a truth bomb on him
Ask Amy: Husband doesn’t feel right after wife’s sister drops a truth bomb on him

05/02/2024

Dear Amy I grew up in the same town as Carly the woman I later married Her older sister Su...

ShoutoutGive Shoutout
500/500