Nearly Half of China’s Major Cities Are Sinking Based on Satellite Data [Study]

The big cities in China are already slowly sinking. This puts locals at risk of flooding and more.

Major Cities In China Are Sinking

A new study examined 82 cities in China with a population of over 2 million. It used radar pulses from satellites to identify the changes in distance between the satellites and the ground and measured the elevation of the cities that had changed from 2015 to 2022.

They discovered that 45 percent of urban land in the country was sinking faster than 3 mm annually, while 16 percent was sinking at over 10 mm a year.

According to the study, Shanghai had already sunk about 3 m over the previous 100 years, but it was still subsiding. Beijing and Tianjin, among other cities, were particularly impacted.

According to Robert Nicholls, a University of East Anglia professor of climate adaptation who was not involved in the study, the subsidence is caused by various reasons.

From a geological perspective, many people in China reside in recently sedimented regions. Thus, these regions diminish as groundwater is removed or soils are drained.

Nicholls issued a warning, pointing out that subsidence increases the risk of flooding brought on by climate change and jeopardizes the structural integrity of important infrastructure and structures, especially in coastal towns that exacerbate sea-level rise.

Due to subsidence, China already loses more than 7.5 billion yuan, or roughly $1.05 billion, annually.

That being said, the issue is not exclusive to China. Approximately 2.4 million square miles, or 6.3 million square kilometers, of land, were at risk of subsidence worldwide, with Indonesia being one of the worst-affected nations.

According to the United States Geological Survey (USGS), the issue has also affected areas of the United States, directly affecting more than 17,000 square miles of land in 45 states.

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Mexico City Is Sinking, Too

Mexico City's topography is reducing, and the city is currently losing 1.5 feet of land each year in some places. The subsidence was causing the city to sink dangerously. Geophysicist Enrique Cabral-Cano spoke with Dario Solan-Rojas about the city's disorienting construction layout. According to the most recent simulation run by the two researchers and their colleagues, certain parts of Mexico City are sinking up to 20 inches a year.

According to their estimates, places could drop by as much as 65 feet over the next 150 years. The center of Mexico City may be 100 feet underwater.

The 9.2 million city residents that are sinking the fastest in the world are facing a slow-motion calamity that began with the bending and tilting that Dario Solano-Rojas saw.

The problem stems from Mexico City's defective foundation. The Aztec capital, Tenochtitlan, was built in a hillside basin on an island in Lake Texcoco.

When the Spanish attacked, destroyed Tenochtitlan, and massacred its people, the lake had already been drained, and buildings were being built on top of it. The vast metropolis, currently known as Mexico City, remained until the lake disappeared.

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