Scientists identify 99 coastal cities worldwide – home to at least 200 million people – that are SINKING … is YOUR home at risk?
At least 200 million people worldwide could be forced from their coastal homes after scientists revealed they are sinking at up to five centimeters a year.
Researchers from the University of Rhode Island analyzed 99 places and found that most are sinking faster than sea levels are rising, but 34 places are sinking by more than an inch per year.
The team discovered four sinking ‘hotspot’ cities in Bangladesh, China, the Philippines and Pakistan, with annual subsidence rates of up to five centimeters.
The Tampa Bay Area, Florida, is also sinking quickly; New Zealand Auckland; Taipei in Taiwan; and the Turkish capital Istanbul, these cities are home to more than 22 million people.
Researchers from the University of Rhode Island analyzed 99 places and found that most are sinking faster than sea levels are rising. Four hotspots have been identified in Asia. Tampa Bay Florida is also sinking quickly
The study used satellite images of all six continents from 2015 to 2020, finding that every continent had at least one sinking city.
The European satellites collected the data by sending microwave signals to Earth and then recording the bouncing waves.
By measuring the timing and intensity of those reflected waves, the team determined the height of the ground to the nearest millimeter.
And because each satellite flies over the same part of the planet every 12 days, the researchers were able to track how the ground deformed over time. Scientific news reports.
Meng (Matt) Wei, an oceanographer at the University of Rhode Island and one of the study’s authors, said, “Many cities are planning for sea level rise, but they are unaware of the amplifying effect of coastal subsidence.”
For example, Wei didn’t observe it land subsidence in Barcelona, Spain, but found that the airport, port and a residential area are all sinking faster than rising sea levels.
The team uncovered four cities with more than 386 square kilometers of land under a 10-meter elevation that is rapidly sinking: Chittagong (Bangladesh), Tianjin (China), Manila (Philippines), and Karachi (Pakistan).
Scientists say the sinking is due to excessive groundwater extraction, but other lands are sinking due to human activities such as mining, constriction and fossil fuel extraction.
The team’s analysis focused on finding threats of coastal flooding, focusing on storm surges, which led them to investigate areas in low-lying areas.
This led them to uncover four cities with more than 386 square kilometers of land under a 10-meter elevation that was rapidly sinking: Chittagong (Bangladesh), Tianjin (China), Manila (Philippines), and Karachi (Pakistan).
And the combined population of these four cities is 59 million.
‘The maximum subsidence rate in Tianjin exceeds 4 cm/yr LOS (nearly 20x average sea level rise), in Chittagong and Manila exceeds 20 mm/yr LOS (nearly 10x average sea level rise), and in Karachi exceeds 1 mm/yr (approximately 5x average sea level rise),” reads the study published in the journal Geophysical research letters.
Scientists say the sinking is due to excessive groundwater extraction, but other lands are sinking due to human activities such as mining, constriction and fossil fuel extraction.
The group includes the Tampa Bay Area in Florida, consisting of Tampa, St. Petersburg and Clearwater and home to more than three million residents, making it the eighth largest metropolitan area in the US.
A stretch of 24 kilometers along the coast is sinking faster than more millimeters per year.
While the results may sound shocking, there is hope that some of these cities will recover. Land subsidence in Jakarta, Indonesia has been significantly reduced over the past twenty years, from 23.5 centimeters per year to 2.5 centimeters per year.
The Turkish capital Istanbul has a population of 15 million and the study shows that this city is sinking at the same rate as the Tampa Bay Area.
Nigeria’s Lagos, Taiwan’s Taipei, Mumbai in India and Auckland, New Zealand’s largest city, are also declining by two millimeters per year.
Together these cities are home to 63 million people.
While the results may sound shocking, there is hope that some of these cities will recover.
Parts of California sank rapidly about 60 years ago, but the subsidence was stopped by changes in groundwater management.
And even land subsidence in Indonesia has been significantly reduced over the past twenty years, from 23.5 centimeters per year to 2.5 centimeters.