Who is to blame? The skyscrapers. That’s the conclusion of a study on the future of this city. Yes: New York is sinking. The article was published in Earth Future.
The city sinks between one and two millimeters a year due to the weight of its towering buildings. But some parts of the city sink much faster. Almost at the same rate that tectonic plates rebound when glaciers melt.
Slow sinking
Deformation could pose a problem for this low-lying city, home to more than eight million people. Strategies are expected to be developed to counteract the increasing risk of flooding and rising sea levels.
“The aim of the report is to raise awareness. Every high-rise building constructed in coastal, riverine, or lake areas could contribute to the risk.” Geologist Tom Parsons of the U.S. Geological Survey writes this.
What was done in this new study? They calculated the cumulative mass of the more than one million buildings in New York. It turned out to be 764,000,000,000,000 kilograms. They converted the mass of the buildings into downward pressure by taking into account the force of gravity.
Clay-rich soils and artificial fills are especially prone to subsidence. The average at a sample site in Lower Manhattan is 294 mm. This was compared with satellite data measuring land surface height. The team plotted their subsidence estimates citywide.
Emblematic
New York is sinking. It ranks third in terms of its exposure to future flooding. Much of Lower Manhattan is only one and two meters above present sea level.
“New York is emblematic among coastal cities that are sinking. There is a shared global challenge to mitigate against a growing flood hazard,” they conclude. A 2022 study of 99 coastal cities concludes that land subsidence could be a bigger problem than sea level rise. In most of the cities studied, land sinks faster than sea level rises. Residents will experience flooding sooner than climate models predict.
