By Elaine Kurtenbach
The Associated Press
SHANGHAI (AP) — This city of 20 million rose from the sea and grew into a modern showcase, with skyscrapers piercing the clouds, atop tidal flats fed by the mighty Yangtze River.
Now Shanghai’s future depends on finding ways to prevent the same waters from reclaiming it.
Global warming, melting glaciers, and polar ice sheets are raising sea levels worldwide, leaving tens of millions of people in coastal areas and on low-lying islands vulnerable to flooding and other weather-related catastrophes.
Shanghai, altitude roughly 10 feet above sea level, is among dozens of great world cities — including London, Miami, New York, New Orleans, Mumbai, Cairo, Amsterdam, and Tokyo — threatened by sea levels that are now rising twice as fast as projected just a few years ago, expanding from warmth and meltwater. Estimates of the scale and timing vary, but Stefan Rahmstorf, a respected expert at Germany’s Potsdam Institute, expects a 3-foot rise in this century and up to 15 feet over the next 300 years.
Chinese cities are among the largest and most threatened. Their huge populations — the Yangtze River Delta region alone has approximately 80 million people — and their rapid growth into giant industrial, financial, and shipping centers could mean massive losses from rising sea levels, experts say.
The sea is steadily advancing on Shanghai, tainting its freshwater supplies as it turns coastal land and groundwater salty, slowing drainage of the area’s heavily polluted flood basin and eating away at the precious delta soils that form the city’s foundations.
Planners are slow in addressing the threat, in the apparent belief that they have time. Instead, Shanghai has thrown its energies into constructing billions of dollars worth of new infrastructure: new ports, bridges, airports, industrial zones, right on the coast.
“By no means will Shanghai be under the sea 50 years from now. It won’t be like the ‘Day After Tomorrow’ scenario,” says Zheng Hongbo, a geologist who heads the School of Earth Science and Engineering at Nanjing University.
“Scientifically, though, this is a problem whether we like it or not,” says Zheng, pointing to areas along Shanghai’s coast thought to be shrinking due to erosion caused by rising water levels.
“We used to play on the river banks and swim in the water when I was growing up. But the river is higher now,” says Ma Shikang, an engineer overseeing Shanghai’s main flood gate, pointing to homes below water level near the city’s famed riverfront Bund.
Twice daily, the 330-foot-wide barrier, where the city’s Suzhou Creek empties into the Huangpu River, is raised and lowered in tandem with the tides and weather, regulating the city’s vast labyrinth of canals and creeks.
Shanghai is considering building bigger barriers — like those in London, Venice, and the Netherlands — to fend off potentially disastrous storm surges, most likely at the point 18 miles downstream where the deep, muddy Huangpu empties into the Yangtze.
“We are studying this, but it is extremely complicated,” said Sang.
“If the research determines that the sea level will rise further, then we will need to build the walls higher. But this is still under research,” he said.
Such projects usually require several decades of planning and construction, and with sea levels rising, they will likely have to be adjusted, given the unknowns of climate change.
“Nobody — no municipal or provincial government, and no central government agency — is preparing adaptation plans for Shanghai or the Yangtze Delta,” says Edward Leman, whose Ottawa-based consultancy Chreod Ltd. has published research on the issue. “They must begin now, as investments and decisions made today will have a major impact in the coming years.”
Extreme weather will aggravate the already precarious situation for many. In September, Tropical Storm Kestana left 80 percent of the Philippine capital, Manila, under water. Newspaper photos showed much of Haikou, on China’s southern coast, flooded, as Vietnam evacuated more than 350,000 people from the storm’s path.
Impoverished Bangladesh is spending billions of dollars on dikes and storm shelters, while seeking international aid to help it adapt to flooding that could force up to 35 million of its people to relocate by 2050.
In the future, communities unable to move may instead end up adapting buildings and infrastructure to accommodate higher water levels, says Hui-Li Lee, a landscape architect who is working on several projects in the region.
“There are many things we cannot account for, but if we know an area is going to flood, then we have to plan for that,” Lee said. “When we look at a map, we have to think that 30 years later or 50 years later, everything will be below sea level.” ♦