The Great Wall of China was built centuries ago to defend against nomadic tribes from the north. While this threat is now dead and buried, a new menace is lapping at China’s frontiers: rising sea levels. Could another great wall be the solution?
Climate change has raised the average global sea level by around 24 centimeters (9 inches) since 1880, as per the National Oceanic and Atmospheric Administration (NOAA), primarily due to melting glaciers and ice sheets, plus the thermal expansion of seawater as it warms. China's coastline is one part of the world that is extremely vulnerable to this shift and it’s already feeling the burn of record-breaking sea level rise, enduring significantly higher levels than the global average.
Its shores are also home to millions upon millions of people living within many of the country’s bustling economic hubs, including Shanghai, Shenzhen, Guangzhou, Dongguan, and Hong Kong.
Some Chinese cities are already preparing for the storm by building improved drainage systems, artificial wetlands, and underground storage. Scientists and engineers have suggested that a retractable barrier system could be built at the mouth of the Huangpu River to protect Shanghai, much like London's Thames Barrier. However, city officials have reportedly been discussing this project for decades with little progress.
One ambitious idea is to construct a “Great Seawall” complex in defense of its coasts. The Chinese government has built extensive sea walls since World War Two, but this system is likely to be inadequate with the new specter of climate-driven sea level rise.
To update the old system, a network of seawalls – measuring 430 kilometers (267 miles) in total – is currently under construction in China and some experts are forecasting a massive seawall construction effort in the coming decades, the Economist reports.
How this might take shape is uncertain, although it’s clear many other coastal countries in Asia have already made major infrastructure plans to remedy the issue. Since 2014, Indonesia has been building the Giant Sea Wall Jakarta, a vast megaproject that involves constructing a giant seawall, water reservoirs, and reclaiming flooded land. With Jakarta continuing to literally sink, the 46-kilometer (29-mile) wall is set to guard the city by 2030.
Serious floods have hit the Indonesian capital every few years, with tens of thousands of people often displaced. The threat of sea-level rise has become so severe it’s estimated that one-third of the city could be submerged by 2050 and the government is seriously looking to relocate the capital to Kalimantan, a yet-to-be-built city on the island of Borneo.
Drowning cities are a problem that many parts of the world will have to face in the next few decades, not excluding Europe and North America. For instance, coastal cities like Miami, Houston, and New Orleans could be facing real problems with sea-level rise much sooner than previously thought.
While China is not alone with its future flooding troubles, their recent track record shows they have a taste for colossal engineering megaprojects – and often the means to deliver them.