Key facts
- China's coastal cities like Shanghai and Hong Kong face sea-level rise 15-20% higher than the global average.
- Melting Antarctic ice and gravitational shifts are contributing to higher sea levels.
- Land subsidence, often from groundwater extraction, exacerbates sea-level rise in Chinese delta regions.
- Shanghai has sunk over 1 meter in some areas due to groundwater use.
- Annual economic losses from rising seas and subsidence in China are estimated at $1.5 billion.
- China is implementing adaptation strategies including groundwater regulation and "Sponge City" concepts.
International scientists warn that China's densely populated coastal cities, including Shanghai and Hong Kong, are facing sea-level rise that will be 15 to 20 percent higher than the global average. This phenomenon is driven by gravitational shifts caused by melting Antarctic ice, which redistributes water across the globe.
Research indicates that global sea levels have been rising at the fastest rate in at least 4,000 years, averaging 1.5 millimeters per year since 1900. China's coastal regions are particularly vulnerable due to a combination of global sea-level rise and localized land subsidence, often exacerbated by excessive groundwater extraction. Some areas of Shanghai have sunk more than one meter during the 20th century due to this practice, significantly increasing their sensitivity to rising seas.
The consequences of this "double crisis" include increased flooding, damage to property and infrastructure, and threats to the global supply chain. The estimated average annual economic losses for China from these factors have reached $1.5 billion. Coastal erosion and saltwater intrusion also pose risks to freshwater supplies and ecosystems.
In response, China has recognized its vulnerability and is implementing adaptation strategies. These include stricter land-use planning, ecological protection, regulating groundwater use to slow subsidence, and developing the "Sponge City" concept for stormwater management. The country has also constructed and reinforced over 12,000 km of dykes.