New York is sinking fast, and new research shows that the “bigger is better” tenet of real estate developers is to blame.
A team from the US Geological Survey and the University of Rhode Island has found that the weight of the city’s huge skyscrapers is causing the five boroughs to sink by one to two millimeters a year.
The team analyzed the weight of 1,084,954 buildings constructed in a 302-square-mile city, including more than 6,000 high-rise buildings and 247 skyscrapers over 150 feet tall.
As these giants push the ground beneath them closer to sea level, climate change is lifting the ocean to accommodate them.
While a few millimeters might not sound catastrophic, some parts of the city are sinking much more rapidly, keeping pace with the fastest movements at which Earth’s tectonic plates are known to move.
For their new study, the scientists first calculated the total mass of over a million buildings in New York: 764,000,000,000 kilograms or 1.68 trillion pounds
“It can be made worse by storms,” geologist and study co-author Tom Parsons of the US Geological Survey told .
“Obviously there have been some events in New York City where hurricanes have come in.”
A sinking city and rising ocean tides, Parsons said, would put New York at greater risk of being swamped by flooding the next time a hurricane like Sandy or Ida hits the Atlantic Seaboard.
“That’s where a lot of the flood risk comes from,” says Parsons. “Not necessarily that the island will be completely submerged — at least not anytime soon.”
“But when these extreme events happen, there can be flooding.”
Parsons and his colleagues said they are probably underestimating the seriousness of the situation because their research didn’t take into account the exposure to other heavy elements like asphalt roads, concrete sidewalks, railroads or the rest of New York City’s infrastructure.
Last year, some of the co-authors of the University of Rhode Island study listed the Big Apple alongside 98 other coastal cities around the world that are also drowning under the weight of their majestic skylines.
In most of the cities they studied, the land below them is receding faster than sea levels are rising due to climate change — a dangerous combination that threatens residents with greater risks of flooding faster than today’s climate models predict.
For this new study, the scientists first calculated the total mass of the more than one million buildings in New York: 764,000,000,000 kilograms, or 1.68 trillion pounds.
Dots marked in blue show where researchers have detected the strongest sinking as observed by satellite. Each point reflects a drop greater than −2.75 mm/year
In this image, the same bruises are compared to modeled estimates of the pressure caused by heavy building loads
By examining the total weight distributed across a grid of 100-by-100-meter squares, the team was able to convert the building’s mass into a clear measure of the downward force pressing on the bedrock beneath the city.
They then compared this work to satellite imagery, which can be used to measure changes in land surface elevation, and matched those measurements to their citywide estimates to compare their model with real-world data.
They said another missing factor that could exacerbate the problem even faster is groundwater drainage and pumping, which could essentially help support the pressure coming down from buildings to further ingest the dirt and rock underneath condense.
“The purpose of the paper,” write USGS’s Parsons and his University of Rhode Island colleagues, “is to raise awareness that each additional high-rise built on the coast, river, or lakefront contributes to could contribute to future flood risk.’