Water

Country Water Action: People’s Republic of China
Shanghai Prepares for Climate Change
September 2007

Few people in Shanghai ever think that their future could be defined by the ocean’s rising tides. Despite dire climate change predictions from scientists and the media, the public could not imagine their city being engulfed by seawaters. But city officials and local experts know they are racing against time to win a knotty battle with global warming. Will their plans hold water?

Contents Saving Sinking Shanghai Top Global-Warmer Land Versus Sea Shanghai Water Gate Great Sea Wall

Shanghai is the most bustling metropolis in the People’s Republic of China (PRC). Located at the mouth of the Yangtze River, it is also one of the largest port cities in the world. Very soon, though, it may be a part of the East China Sea as rising sea-levels resulting from drastic shifts in the earth’s climate threaten to engulf the city.

“The rise of sea levels is indisputable,” says Zheng Hongbo, a professor at the School of Ocean and Earth Science at Shanghai Tongji University. “We could continue to search for the exact causes for a long time but in terms of the dangers it poses to Shanghai, we have little time. We have to take it very seriously.”

The scenario Shanghai faces may not be as frightening as presented in the acclaimed environmental documentary “An Inconvenient Truth,” where former United States vice-president Al Gore warns of the city’s submergence. Nevertheless, it has already caused some marine experts to call for drastic counter-measures—from building water gates to prevent sea storms to erecting an ocean embankment all along the coastal line.

But Shanghai residents refuse to contemplate the worst. Local resident Hu Yang is typical in his aloof reaction to apocalyptic predictions about the sinking of his city: “It is hard to know for sure about all these scientific predictions, but if the sea indeed rises a lot, a mere embankment will not help us.”

Still, Shanghai leaders are bracing for the slow effects of creeping sea water—coastal erosion, salt water intrusion into the fresh water of the Yangtze river, and giant sea waves created by storms.

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Scientists have been at odds over who would suffer most from the consequences of global warming. A report by the Intergovernmental Panel on Climate Change (IPCC) analyzing the impact of greenhouse gas emissions states that the most vulnerable people in Asia will be the rural poor who rely on river delta for their livelihoods. Britain-based International Institute of Environment and Development, meanwhile, says Shanghai and other coastal cities in Asia are at risk. Their figures suggest that sea levels at Shanghai and Tianjin, another coastal city in northern China, could rise by 60 centimeters by 2050.

With much of its energy from coal-fired power stations, China has become the second biggest emitter of greenhouse gases that are linked to global warming. The country is in the midst of unprecedented industrialization and some experts expect it will surpass the United States this year as the world’s top global-warmer. The country is also particularly vulnerable to climate change because its water and land resources are already stretched thin and many of its major economic centers sit in low-lying coastal areas.

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Shanghai’s climate change problems are further complicated by the city’s constant reclamation of land from the sea to satisfy the needs of its relentless growth. A rise of 60 centimeters in seawater is a significant threat to Shanghai’s 18 million people. The city itself lies in a low-elevated area of the Yangtze River delta, and the area where the Yangtze pours into the East China Sea sits only at 3-5 meters above sea level.

“Such rise in sea levels would destroy the fragile equilibrium between economic growth and land reclamation,” warns geologist Zheng. “If land growth slows down, the economy would slow down too. This is the biggest worry for the government.”

Shanghai is often described as one of the world’s biggest construction sites, reclaiming roughly 3,000 hectares of land from the sea every year. Reclaimed land is now a feature of Shanghai daily life. Some of the city’s impressive new landmarks, like its futuristic airport in the financial district of Pudong, are all built on reclaimed land. And city leaders are now thinking of building a brand new eco-city on the marshy land of Shanghai’s Chongming island, another reclaimed area.

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Shanghai experts are now proposing to build a water gate at Wu Song Kou Wai, near the Yangtze estuary, to prevent sea storms and lower the risk of flooding. It was a plan first put forward in the 1990s, but was never implemented.

Since 1998’s devastating summer floods, however, when Yangtze’s swollen waters killed more than 3,000 people and left 14 million homeless, talks about the water gate plan for Shanghai resurfaced. Local experts argue that building such a gate would be less costly and more effective than raising and re-enforcing the current river dykes.

Meteorologists have warned of more typhoons, floods and drought this year than at any time in the past decade because of global climate change. “The most severe floods since 1998 might hit the Yangtze this summer,” said Zheng Guoguang, director of the China Meteorological Administration.

“We have been looking at plans to build a water gate near the river estuary as a way of lessening the flooding aftermath of a severe sea storm,” says Zhang Zhenyu, spokesman of Shanghai Flood Risk Information Center.

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Another proposal—to erect sea walls, the equivalent of a coastal Great Wall—has been put forward by experts in Tianjin, hoping that such embankments can also fend off the advancing tides. But some have dismissed such proposals as missing the core of the crisis.

Shanghai-based columnist Chen Weihua argued that instead of building sea walls, China should tackle its deteriorating environment to preempt doomsday scenarios for its coastal cities. “Erecting a strong embankment may not make people feel safe,” Chen said. “Just look at the numerous cases of fortifications rupturing along China’s major rivers and lakes in the last few decades, and the cracking of a sea wall will surely inflict damage of much larger magnitude, considering the might of the ocean as demonstrated in the Asian tsunami of December 2004.”