New York City could sink under the weight of its skyscrapers

New York City is sinking because of its own skyscrapers. The result came from a new study that modeled the geology beneath the Big Apple city against satellite data, which suggests its footprint is collapsing to Earth. Technically it takes the name of subsidence, the gradual settling or sudden sinking of the earth's surface, which occurs when soft sediments move or when the loads they carry down to the ground push it even deeper. However, there are many causes, but it is also true that the weight of the cities themselves is rarely studied. According to the study data, New York is sinking at a rate of 1-2 millimeters per year, under the weight of its skyscrapers. While millimeters may seem small to us, in reality there are some parts of the city that are subsiding much faster, on par with the faster observed rates at which tectonic plates bounce as glaciers melt. Such deformation could spell serious problems for the low-lying city that is home to more than 8 million people, so the findings should encourage further efforts to develop mitigation strategies to counter the increased risk of flooding and sea level rise. As explained by geologist Tom Parsons of the United States Geological Survey and his colleagues at the University of Rhode Island: “The point of the paper is to raise awareness that each additional high-rise built in coastal, river or lakefront environments could contribute to the future risk of floods". In this new study, later published in Earth's Future, Parsons and his colleagues calculated the cumulative mass of more than 1 million buildings located in New York City, which is 764,000,000,000 kilograms. Next, they divided the city into a grid of 100 by 100 meter squares and converted the building mass into downward pressure taking into account the pull of gravity. Their estimates include only the mass of the buildings and their contents. These new calculations improve on past observations of subsidence in the city by accounting for the complex surface geology beneath New York City that consists of sand, silt and clay deposits and rock outcrops. Working on the behavior of these substrates, the researchers showed that clay-rich soils and artificial fill are quite prone to subsidence. More "elastic" soils bounce after construction, while the rock, building many skyscrapers on it, does not move so much. Unfortunately, increased urbanization, including the drainage and pumping of groundwater, could only increase New York's subsidence problem, according to the researchers. The Big Apple could be under water by 2050, with parts of the city sinking nearly 11 centimeters a year due to groundwater extraction.