As sea levels rise, Shanghai is sinking–and at least one study ranks it as the most vulnerable city in the world for future floods. A new series of maps looks at what would happen to it, and other major coastal cities in China, if all of the ice sheets in the world melted.
“China has massive cities and populations right at sea level that are unmatched by anything that exists in North America,” says cartographer Jeffrey Linn, who mapped out a submerged version of the Chinese coast for ChinaFile after doing the same thing for several cities in the U.S., including New York, Los Angeles, and Portland.
While the New York City metropolitan area has a population around 19 million, and Greater LA has around 18 million, the Pearl River Delta is home to over 65 million people.
“Greater Shanghai alone has over 24 million people, and will ultimately be devastated by rising seas,” says Linn. “U.S. cities aren’t that large, and we don’t have anywhere near the populations in low-lying estuary areas that will be at risk. There are many U.S. cities that I haven’t modeled, like the Florida Panhandle and the Gulf Coast that I believe will have similar issues, but not similar populations.”
Like Linn’s other maps, these show an extreme future that’s unlikely to happen for at least a millennium, if not longer. But even if Shanghai isn’t immediately submerged, it’s still facing major short-term threats. The city has sunk around six feet since the 1920s, and its flood wall is weak. With the right combination of high tide and a typhoon, a Hurricane Sandy-like storm–or worse–is very possible. Rising sea levels make that more likely to happen.
Up the eastern coast of China, the city of Qingdao is also at risk. In Linn’s maps, most of the region around Qingdao disappears, turning the peninsula into a series of small islands. By 2070, the city could have more than $600 billion in assets at risk from flooding.
Large chunks of Taiwan would also disappear in extreme sea level rise, and today face similar short-term risks. Though Linn didn’t map the full coastline of China, the three areas he focused on show where 40% of the population resides–and populations are still quickly growing as new megacities emerge. “We really wanted to show where the greatest impacts to people would be,” he says.