.-') _      .-') _  
                      ( OO ) )    ( OO ) ) 
          .-----. ,--./ ,--,' ,--./ ,--,'
         '  .--./ |   \ |  |\ |   \ |  |\  
         |  |('-. |    \|  | )|    \|  | ) 
        /_) |OO  )|  .     |/ |  .     |/  
        ||  |`-'| |  |\    |  |  |\    |   
       (_'  '--'\ |  | \   |  |  | \   |
          `-----' `--'  `--'  `--'  `--'
       lite.cnn.com - on gopher - inofficial
       
       
       ARTICLE VIEW: 
       
       270 million people are living on sinking land in China’s major
       cities, new study finds
       
       By Rachel Ramirez, CNN
       
       Updated: 
       
       2:00 PM EDT, Thu April 18, 2024
       
       Source: CNN
       
       underneath millions of peoples’ feet in China’s major cities due to
       human activities, putting the country’s coastal areas more at and
       rising sea levels, new research shows.
       
       Nearly half of China’s urban areas comprising 29% of the country’s
       population are sinking faster than 3 millimeters (about 0.12 inches)
       per year, according to the published Thursday in the journal Science.
       That’s 270 million people living on sinking land.
       
       Meanwhile, 67 million people are living on land that is subsiding
       faster than 10 millimeters (0.4 inches) each year.
       
       China’s rampant groundwater extraction is one of the primary factors
       for subsidence, researchers said. Cities have been pumping water from
       underground aquifers faster than it can be replenished, a situation
       exacerbated by climate change-fueled drought. Excessive pumping lowers
       the water table and causes the overlying land to sink.
       
       The land is also sinking due to the growing weight of cities
       themselves. Soil can compact, naturally from the weight of sediments
       accumulating over time and from heavy buildings pressing down on the
       ground, causing the land to steadily sink.
       
       Land subsidence isn’t just a problem in China. In the US, , including
       , are sinking. In the Netherlands, 25% of its lands have sunk lower
       than sea levels. And in , likely the world’s fastest subsiding city,
       land is sinking at the speed of up to 50 centimeters, or nearly 20
       inches, a year.
       
       The impact of sinking is typically worse along the coasts, where the
       sea level is rising at the same time. This combination exposes more
       land, people and property to destructive flooding.
       
       The study suggests roughly a quarter of China’s coasts will be lower
       than sea level because of subsidence and projected sea level rise,
       priming the area for colossal damage and putting lives at risk.
       Tianjin, Shanghai and areas around Guangzhou are significantly exposed
       to both issues, the study found.
       
       But some coastal areas in China have already built physical protection
       from the growing risk of inundation, and the study does not take those
       protections into account. In Shanghai, for example, Shengli Tao,
       co-author of the study and professor at Peking University, said the
       city has built “impressive” dike systems that are meters tall.
       
       “Such massive coastal dike systems will largely reduce the risk of
       being inundated even given both land subsidence and sea level rise,”
       Tao told CNN. “I am not aware of other countries that have built such
       massive dike systems.”
       
       Thursday’s study is “scientifically robust” and did “a fine
       job” of highlighting that subsidence is not just a “coastal
       problem,” said Leonard Ohenhen, a doctoral researcher at Virginia
       Tech who recently published a study on land subsidence in the US.
       
       “Most urban cities experience land subsidence, but we focus our
       attention on coastal cities because of sea level rise,” Ohenhen, who
       was not involved with the study, told CNN. “However most urban
       cities experience land subsidence at rates comparable or even greater
       than subsidence in coastal cities.”
       
       Tao said the Chinese government is addressing the sinking in a few
       ways, including implementing strict laws to control groundwater pumping
       in the last few years. Shanghai and surrounding areas have been
       limiting groundwater withdrawals, which has slowed the region’s rate
       of subsidence. Decades ago, Shanghai’s subsidence was a significant
       issue, Tao said.
       
       China has also been pumping water from the Yangtze River in southern
       China to northern China – including to Beijing – which has suffered
       from water shortages. The project prevents the need for over-pumping
       groundwater and has stopped land subsidence in Beijing, the study
       found.
       
       “I believe China’s government efforts will address the issue of
       land subsidence,” Tao said. “But I would suggest to keep
       controlling groundwater withdrawals for major cities and constantly
       maintain dike systems in coastal lands.”
       
   DIR  <- back to index