From New York to Baltimore, the US East Coast cities are sinking. Here’s why

The unsettling truth that New York City, Long Island, and other coastal cities in the United States must face is that they are sinking. In a new study, although the sinking may appear to be slow, the researchers stress that the repercussions are genuine and pose a threat to these places’ future. It serves as a reminder to both citizens and legislators to solve this escalating issue. But why are US East Coast cities sinking? Let’s take a closer look. What is causing the land to sink? According to research published in the Proceedings of the National Academies of Sciences, buildings and natural processes are causing the land to drop at a concerning rate of two millimetres (.08 inches) every year, which raises questions about flooding and long-term viability. The US Geological Survey and Virginia Tech research team used radar and satellite imagery to produce digital terrain maps that pinpoint the precise locations where critical infrastructure is most at risk from land subsidence. “We measured subsidence rates of two millimetres per year, affecting more than two million people and 800,000 properties on the East Coast,” Virginia Tech professor and researcher Manoochehr Shirzaei said, according to NDTV. The anticipated current rate of sea level rise worldwide is four millimetres per year, which further complicates the situation. Additionally, according to Science Alert, there is a sinking of more than five millimetres (0.2 inches) per year in various regions along the mid-Atlantic coast, spanning up to 3,700 square kilometres, or more than 1,400 square miles. That exceeds the speed of the sea level increase by four times. The study also emphasises the effects that sinking ground can have on large cities such as Virginia Beach, Norfolk, and Baltimore. The sinking soil only increases the risk for these coastal cities, which are already vulnerable to weather-related problems like storms. Lead author Leonard Ohenhen, a graduate student working with Shirzaei, said in a press release, “Continuous unmitigated subsidence on the US East Coast should cause concern. This is particularly in areas with a high population and property density and a historical complacency towards infrastructure maintenance.” How dangerous is it? “Here, we show that 2,000 to 74,000 square kilometres land, 1.2 to 14 million people, 476,000 to 6.3 million properties, and greater than 50 per cent of infrastructures in major cities … are exposed to (these) subsidence rates,” the study said. “We know to some extent that the land is sinking. Through this study, we highlight that the sinking of the land is not an intangible threat. It affects you, me, and everyone; it may be gradual, but the impacts are real.” The authors highlight the serious threat that rising sea levels pose to large metropolitan regions like New York, Norfolk, and Baltimore, where valuable properties and dense populations are directly intersected. “The problem is not just that the land is sinking. The problem is that the hotspots of sinking land intersect directly with population and infrastructure hubs,” said Ohenhen, according to Science Alert. “For example, significant areas of critical infrastructure in New York, including JFK and LaGuardia airports and [their] runways, along with the railway systems, are affected by subsidence rates exceeding 2 millimeters per year.” The National Aeronautics and Space Administration reported in September that between 2016 and 2023, the areas surrounding LGA and Arthur Ashe Stadium, home of the US Open, had decreased at rates of 3.7 and 4.6 millimetres annually, as per the New York Post. In September, a widely shared video also showed a terrifying flood situation at LaGuardia Airport, with travellers having to wade through ankle-deep water. In addition to having serious negative effects on the environment, infrastructure collapse can result in a significant loss of life. What are experts saying? “All climate change models show that in the future, the storms, the hurricanes will get more intense,” Klaus Jacob, a professor emeritus at Columbia University’s Lamont-Doherty Earth Observatory, previously told The Post, adding_,_ “So that probably means stronger storm surges, higher storm surges, and that’s more risk and lost protection for the city.” One glaring example of these concerns is this week’s nor’easter, which left a terrible amount of floodwaters in coastal areas like Long Island and Connecticut. However, Jacob cautions that the immediate tri-state region is not the only area at risk. “Long Island, Staten Island, Brooklyn, Queens, the Bronx—you name it. The Hudson Valley all the way up to Troy… I would say anything at elevation 20 [feet above sea level] and below is an extreme risk. There’s a marginal risk for elevations between 20 and 30 feet.” In his opinion, New York City—particularly downtown Manhattan—will have to transform into a contemporary Venice by the end of the century. “If we want to keep skyscrapers and other buildings functioning, they will need to become mini islands that are standing in the water,” Jacob said. With inputs from agencies