- New York City is sinking at a rate of 1 to 2 mm per year, according to a recent US government study.
- Venice, Italy — the “floating city” — is sinking at the same rate.
- The problem of subsidence is likely to worsen as coastal cities continue to grow in population.
New York City, with its towering skyscrapers and seemingly never-ending construction, is so heavy that it’s sinking at the same rate as Venice, Italy — perhaps the most famous rapidly-submerging city.
More than 8 million people call the Big Apple home, and a recent US government report warns that New Yorkers, as well as other residents of coastal cities around the world, are facing a wave of intense subsidence, or the gradual caving in or sinking of an area of land.
And the problem is likely to worsen as coastal cities around the world continue to grow in population and building density, researchers said.
A May report from the United States Geological Survey titled “The weight of New York City: Possible contributions to subsidence from anthropogenic sources” found that New York City is sinking 1 to 2 mm per year as sea levels rise and hurricanes increasingly threaten the region.
Researchers calculated the mass of all the buildings in New York and modeled the subsidence caused by the pressure that those buildings are exerting on the earth. And while 1 to 2 mm is the average throughout the city, some parts of New York City are subsiding even faster.
The threat of sea level rise is three-to-four times higher in New York than the global average along the Atlantic Coast, according to the study, and sea levels around the world are expected to rise 200 to 600 mm by 2050.
New York’s 1 to 2 mm loss per year puts the East Coast city at the same sinking rate as Venice, Italy, the collection of islands known as “the floating city,” according to Venezia Lines, the leading ferry company in the north Adriatic.
Government officials have constructed special barriers to reduce the amount of water that spills over at high tide in Venice, but the ever-encroaching saltwater has already had a “crumbling” effect on Venice’s buildings, Venezia Lines said. The ground floors of many apartments throughout the city are no longer habitable due to subsidence, and experts have suggested the city could be entirely underwater by 2100.
Other cities around the world, including several in the US, are sinking at an even more alarming rate.
“New York is emblematic of growing coastal cities all over the world that are observed to be subsiding,” government researchers wrote in the study. “Meaning there is a shared global challenge of mitigation against a growing inundation hazard.”