China’s Sinking Cities: The Looming Crisis of Subsidence and Rising Sea Levels

Introduction

China’s coastal cities, home to over 400 million people, are facing a dual threat of subsidence and rising sea levels, according to a recent study. The study, published in the journal Science, found that a quarter of China’s coastal land will sink below sea level within a century, putting millions of lives and trillions of dollars in infrastructure at risk.

Subsidence and Sea Level Rise

Subsidence, or the sinking of the land, is a natural process that occurs when the ground settles or compacts over time. However, in China’s coastal cities, the process is being accelerated by human activities, such as the over-extraction of groundwater and the weight of buildings.

The study, conducted by researchers from the Chinese Academy of Sciences and the University of California, Berkeley, analyzed satellite data and found that the rate of subsidence in China’s coastal cities has increased by up to 50% in the past decade. The researchers also found that the subsidence is linked to changes in groundwater levels and the weight of buildings.

At the same time, sea levels are also rising due to climate change. According to the National Oceanic and Atmospheric Administration (NOAA), sea levels have risen by about 3.3 millimetres per year over the past 25 years. In China’s coastal cities, the combination of subsidence and sea level rise is creating a crisis that is only expected to worsen in the coming decades.

Impact on Coastal Cities

The impact of subsidence and sea level rise on China’s coastal cities is already being felt. In Shanghai, the city’s iconic Bund waterfront has sunk by up to 2.6 meters over the past century, while in Tianjin, the city’s central business district has sunk by up to 2.5 meters.

The subsidence is causing a range of problems, from increased flooding to damage to buildings and infrastructure. In some areas, the subsidence has caused roads and buildings to crack, while in other areas, it has led to the flooding of entire neighbourhoods.

The cost of addressing the subsidence and sea level rise crisis in China’s coastal cities is estimated to be in the trillions of dollars. The Chinese government has already spent billions of dollars on measures such as building sea walls and pumping sand onto eroding beaches. However, these measures are only a temporary solution and do not address the root causes of the subsidence.

Expert Opinions

Experts warn that the subsidence and sea level rise crisis in China’s coastal cities is a ticking time bomb. “The situation is very serious and requires urgent action,” said Dr. Xiaojun Yin, a researcher at the Chinese Academy of Sciences and one of the authors of the study. “We need to reduce the extraction of groundwater and find ways to reduce the weight of buildings.”

Dr. Robert Nicholls, a professor of coastal engineering at the University of Southampton, agrees. “China’s coastal cities are facing a perfect storm of subsidence and sea level rise,” he said. “The Chinese government needs to take urgent action to address the root causes of the subsidence and invest in long-term solutions to protect its coastal cities.”

Conclusion

China’s coastal cities are facing a crisis of subsidence and sea level rise that is only expected to worsen in the coming decades. The crisis is being driven by human activities, such as the over-extraction of groundwater and the weight of buildings. The Chinese government needs to take urgent action to address the root causes of the subsidence and invest in long-term solutions to protect its coastal cities.

The cost of addressing the crisis is estimated to be in the trillions of dollars, but the cost of inaction is likely to be much higher. Millions of lives and trillions of dollars in infrastructure are at risk. The Chinese government must act now to prevent a catastrophic flood from engulfing its coastal cities.