New York City Sinking at Alarming Rate: Skyscrapers Pose Risk for Inhabitants and Flooding

You couldn’t imagine New York City without its colossal skyscrapers. However, the weight of these buildings now represents a danger for those over 8 million inhabitants. A study published on May 8 in the journal Earth’s Future estimates that the largest city in the United States is facing a risk of flooding due to sea level rise and subsidence.

What is called sag is a progressive lowering of the surface of the Earth which can be caused in particular by groundwater pumping or the weight of cities. This is what is happening in New York. According to new geology research, the metropolis is sinking on average at a rate of 1 to 2 millimeters per year. It may not seem like much, but some parts sag much faster. Part of the Manhattan neighborhood is only 1 or 2 meters away above sea level.

To arrive at this estimate, the authors made numerous calculations and estimations. For example, they assessed the total mass of more than one million New York buildings, i.e. 764,000,000,000 kilograms. A huge weight that does not take into account roads, sidewalks, bridges and railways.

They also used satellite data and studied soil composition. The city’s surficial geology consists of silt, sand, clay lake, beach deposits and rock outcrops among others, the study reads. Soils rich in clay and artificial fill are particularly susceptible to subsidence, say the researchers.

New York, Jakarta, soon under water?

The subsidence could be made worse by the construction of new buildings but also by the extraction of groundwater combined with rising sea levels, they warn. There world population increases, and a projection estimates that 70% from her goes live in big cities by 2050, they add.

In the future, floods could increase. New York is one of the cities most at risk from future flooding. She’s not the only one. In Indonesia, the capital Jakarta could be under water in barely twenty-five years. Some neighborhoods are sinking nearly 11 centimeters a year due to groundwater pumping.

“The purpose of the article is to raise awareness that each additional high-rise building built on coastlines, rivers or lakeshores could contribute to future flood risk”, write the authors. The challenge is great to try to mitigate the risk of flooding.

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