New York City is sinking: Understanding the Risks and Consequences of Subsidence

If these figures may seem insignificant, they are significant enough to worry the scientific community. Especially since these results only represent an average. Thus some neighborhoods, such as lower Manhattan and parts of Brooklyn or Queens, are sinking much faster (up to twice as fast) as the rest of the city. This difference is explained by the nature of the soil consisting of a mixture of clay, sand and silt.

This phenomenon is called by scientists: “subsidence”. It is a sinking of the earth’s crust, due to an addition of charges to this crust. The risk of this phenomenon is accentuated by the fact that New York is a city located on the coast, that its buildings are therefore located at a very low altitude and that the city is overcrowded. Up to 8 million people are therefore threatened by the waters.

“The aim of this article is to raise awareness that each new high-rise building built by the sea, river or lake could contribute to the risk of future flooding”, says Tom Parsons, geologist at the United States Geological Survey. Parsons and his colleagues calculated the cumulative mass of more than one million buildings in the city, or 764,000,000 tons of buildings, without taking into account the roads, sidewalks, bridges, railways which also accumulate the tons .

With climate change leading to more and more natural disasters, severe weather and rising sea levels, New York is therefore threatened by flooding. The lower part of Manhattan is already between 1 and 2 meters below sea level and is therefore particularly at risk of submersion. In 2012, Hurricane Sandy had already caused flooding in the city. In 2021, forty people lost their lives in a flood caused by the Ida storm.