Are New York City’s Buildings Causing it to Sink?

Newsletter: The Growing Concern of New York City Sinking

A recent study has shed light on the alarming situation of New York City sinking into the ground. The weight of the city’s buildings, estimated at a staggering 1.68 trillion pounds, coupled with rising sea levels, poses a potential threat to the city’s future. The scenario could be similar to Venice, which is gradually slipping into the Mediterranean Sea. Alternatively, New York City might experience a repeat of the devastating Hurricane Sandy that struck in 2012, resulting in flooding caused by ocean water surges.

The gravity of the situation is compounded by the projected rise in sea levels, anticipated to be between 20 and 60 centimeters by 2050. Lower Manhattan, in particular, faces a dire outlook, as it currently sits just 1 to 2 meters above sea level and is sinking at a rate of 1 to 4 millimeters each year. Although the study doesn’t offer a specific timeline for when New York City might dip below sea level, it’s a possibility that could become a reality within a few decades.

So, why is New York City sinking? One contributing factor is the composition of the city’s foundation. Much of Manhattan, as well as Brooklyn, Queens, and Staten Island, was built on sand, clay, and vast amounts of “artificial fill,” including garbage and other debris. This combination of materials seems to accelerate the sinking process. Additionally, the weight of the city’s 1.08 million buildings, along with the effects of the Last Ice Age and excessive groundwater extraction for various purposes, might also contribute to the sinking phenomenon. Moreover, human interference with the land through constant construction and land reshaping further exacerbates the issue. The study also highlights how the development of the East and Harlem rivers has hindered the natural flow of sediment, aggravating the problem.

To measure the extent of the sinking, researchers from the U.S. Geological Survey and the University of Rhode Island Graduate School of Oceanography utilized satellite data. Their findings revealed that New York City has been sinking at an average rate of about 2 millimeters per year between 2015 and 2020, based on the satellite data. Furthermore, GPS data showed an average annual sinking rate of 1.5 millimeters. To determine the impact of buildings, the team employed a pixel-reading algorithm from Microsoft to create 3D models from satellite images. Through this process, they estimated building heights and assumed that reinforced concrete, the most common building material in the city, accounted for everything. Ultimately, this calculation yielded a total weight of 1.68 trillion pounds. The model indicated that lower Manhattan and areas of Brooklyn with substantial amounts of artificial fill would experience the most significant sinkage.

Considering these factors, it raises the question of whether New York City will eventually be underwater. The ever-changing coastline of the city has undergone significant shifts throughout history. Approximately 20,000 years ago, when glaciers receded, the waterline moved about 50 miles inland. If the direst climate predictions come to fruition, there is a possibility that parts of lower Manhattan could be submerged by 2050. This predicament is not unique to New York City; many other coastal cities around the world face similar or even more severe threats. Jakarta, the capital of Indonesia, has already been impacted by extensive flooding, leading the country to plan the construction of a new capital. By 2050, a quarter of the current capital could be underwater.

It is essential to address this growing concern promptly and take precautionary measures to mitigate the potential consequences. The implications of a sinking New York City extend far beyond the city itself, impacting the local economy, infrastructure, and the lives of millions of residents. The study serves as a sobering reminder of the urgent need to address climate change and the rising sea levels that pose a significant threat to coastal cities worldwide.