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Shanghai Struggles to Save Itself from the Sea

The global financial capital may face flooding from rising sea levels as a result of climate change



Michel_r/Wikimedia Commons

SHANGHAI -- Some 1,000 years ago, the Chinese named this city "Shanghai" based on its location. It literally means "above the sea." Those pioneers probably never imagined the situation that confronts this city today: Shanghai is on its way to being below the sea.

Climate change is pushing up the sea level globally. While in Shanghai, such rise is roughly the length of a rice grain in each of recent years, the low-lying city with a population of more than 20 million has had to pour billions of dollars into rebuilding infrastructure to protect against potential floods. It is also revising its growth plans, hoping to reduce its vulnerabilities.

It has used its perch on the Yangtze River Delta to become one of the world's prime financial and shipping centers, but now it also finds itself being menaced by other hazards rooted in climate change. During the past years, the city has suffered more extreme weather, missed rain during the normal wet season and seen a temperature hike almost four times higher than the global level.

Climate change threatens Shanghai's economy in various ways. Because global warming is heating up the sea, local fisheries are expected to see their business drop. Scientists have discovered that fish here do not flourish in hotter water. Typhoons and other forms of extreme weather are scaring away tourists and giving large cargo ships reasons to seek other ports.

But the city's biggest concern remains the slow, steadily mounting threat that comes from sea level rise. Higher tides are washing away the precious delta soil upon which the city's foundations are built, and water supplies are becoming more tainted as seawater intrudes more deeply into the fresh water of the Yangtze.

What stands between Shanghai and drowning is an average 13 feet of land. Construction of thousands of high-rise buildings, combined with the pumping of groundwater, is making the soil subside. The removal of groundwater is now under tighter controls, and water is actually being pumped back to wells, a move that has slowed the city's slump into the East China Sea.

Build a floodgate on the Yangtze?
But that won't save it from another danger. Meteorologists warn of more floods, as giant storm surges can ride in on higher tides to invade the city. To defend Shanghai, engineers have stretched hundreds of miles of levees along its rivers. The lowest of those levees were built to withstand a one-in-1,000-year tidal surge.

Along some major waterways, including by the landmark Bund financial center, where century-old architecture and some ultra-modern glass and steel buildings stand on its two sides, river dikes were built even higher.

Such ambitious infrastructure has already defended Shanghai against the highest tidal surge in modern times, which came during a 1997 typhoon. Experts think it might be able to handle the incremental sea level rise as far out as 2100. But this city was not built on hope; it wants more guarantees.

Zhang Zhenyu, spokesman of Shanghai Flood Control Headquarters, said that the city is considering building a floodgate near the Yangtze estuary. The gate could be raised and lowered in accordance with tide and weather, controlling water flowing in and out of the river.

Although the plan is still under discussion, mainly for its possible negative impacts on ships and nature, it is most likely to get a go-ahead, disclosed Zhang.

"After all, building of such gate would be more effective and less costly [than raising and re-enforcing levees]," Zhang explained, adding that more than $6 billion has already been poured into flood control infrastructure over the last decade.

Destroying natural sea barriers
Shanghai keeps reinforcing riverside barriers, but sometimes it has also been the effort's worst enemy. To catch up with its population boom and support an economy that grows at a double-digit rate almost every year, the land-scarce city has dried up coastal wetlands and filled them with new factories and apartments in its never-ending hunt for more space.

This fuels the city's economy, but it is also weakening the battlefront against climate change, says Yang Fuqiang, a climate expert at the Natural Resources Defense Council. As bulldozers wiped out wetland flora, Shanghai lost its natural barriers that can mitigate erosion and absorb the shock of storm surges, Yang explained. He added that the city should start restoring wetlands instead of reclaiming them.

Ren Wenwei, who heads the Shanghai conservation program at the World Wide Fund for Nature, agrees. "The wetland is not only a home for wildlife, but also serves as a safeguard for the city's 22 million residents," Ren said.

To rebuild this safeguard, Ren and others say, Shanghai is shifting to a new economic engine. The city plans to steer away from land-hungry factories and lure in more bankers who need little more than a desk and computer.

Moreover, Shanghai is showing more enthusiasm about attacking the core cause of climate change: greenhouse gas emissions.

Building a rooftop 'Central Park'
Since 1994, Shanghai has been developing its urban rail network from scratch. Now it is the longest in the world, luring commuters to leave their cars at home.

Meanwhile, the city is also cleaning up its power sources. It demonstrated the first Chinese commercial project to sell solar-derived electricity to the grid. It built the world's first large-scale offshore wind farm outside Europe. And with the help of a more advanced power grid, electricity generated from hydropower is being sent over a thousand miles to Shanghai, allowing it to style itself as the biggest clean energy-consuming city on Earth.

Still, half of the city's power comes from coal, a high carbon-emitting fuel. To emit less greenhouse gases, Shanghai must consume less energy. To that end, regulators have ordered more buildings to be equipped with solar water heaters. They have also doubled electricity prices for some inefficient industries that are high electricity consumers, including steel, cement and leather makers.

Along with this exercise in Chinese command and control come a few carrots. Factories can access financial incentives to upgrade technologies. And residents get subsidized prices for energy-saving light bulbs and more efficient air conditioners.

As a result, Shanghai has cut its energy use by 20 percent, measured against each unit of economic output during the last five years. Looking to the next five years, Shanghai has promised not only to continue this trend, but also for the first time to cap the total amount of energy that it can use.

Impressive as all this sounds, it may not be enough. Until now, Shanghai has been neglecting another key contributor to climate change, says Yang of the Natural Resources Defense Council. Yang notes that as more buildings are constructed here, fewer areas covered with plants, trees and soil are left, weakening the city's ability to absorb carbon dioxide.

Recently, Shanghai began pushing construction to go hand in hand with gardening. According to its plan, by 2015, the building, roofs and walls of new structures and some existing structures will be strewn with newly planted grasses, bushes and flowers. The hope is that, cumulatively, this will create a new carbon-absorbing mass nearly half the size of New York's Central Park.

The added greenery will add some more cool to the city that is trying to save itself from the sea.

Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC. www.eenews.net, 202-628-6500

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