A new study claims that New York City is sinking, increasing the risk of flooding in the city. The study was published this month in the journal Earth’s Future, and it suggests that some areas are sinking far faster than average, descending at an average rate of between one to two millimeters per year.
This phenomenon is known as subsidence, and as the city continues to sink, experts say that it will only see the dangers of flooding grow, especially as sea levels continue to rise. “A deeply concentrated population of 8.4 million people faces varying degrees of hazard from inundation in New York City,” the study warns.
It might sound scary to think of New York City sinking, but it really shouldn’t be much of a surprise, as the city is estimated to weigh a cumulative of 1.68 trillion pounds, according to a report from The Times of Israel. It’s also important to note that the researchers only calculated the weight of the buildings and their contents. They did not measure in the weights of roads, subways, and bridges.
The reason we’re seeing so much sinkage with New York City is that much of the city is built on softer sand and clay. The majority of the city is also built on water, with the more densely packed central Manhattan area being on a narrow island. Because the bulk of the island is over the water, and kind of sinking could open the door to more flooding, which could leave people and buildings in danger.
The researchers say they determined how much New York City is sinking by measuring the weight of the city’s buildings and then modeling how much downward pressure they exert. They found that most of the skyscrapers exert the most downward pressure, though they are built on bedrock, unlike many of the other buildings in the city.
The natural effects of the local tectonic plates can also shift and cause more sinking. It’s definitely something that researchers plan to keep an eye out for as sea levels rise. That’s especially true since the Atlantic Coast faces rising levels three to four times higher than the global average, the study notes.