New York City is sinking—satellite data show that the metropolis is plunging 1 to 2 millimeters on average each year. Some of this is natural, such as residual effects of land settling after the last ice age, and some is caused by people withdrawing groundwater. But the immense weight of the Big Apple’s buildings is also playing a role, according to a study published this month in the journal Earth’s Future.
With the land slowly sinking, the threats already posed by rising sea levels and intense storms just get worse. And New York City isn’t the only coastal urban area that’s sinking.
“Sea level rise is eventually going to pose inundation challenges in New York and globally,” Tom Parsons, a co-author of the study and geophysicist at the U.S. Geological Survey, tells Live Science’s Charles Q. Choi.
The city’s 1,084,954 buildings weigh about 1.68 trillion pounds, the researchers estimated—almost double the weight of all of humanity combined. To predict the amount of sinking due to this tremendous load, the team modeled the buildings and the various types of land beneath them. They found that depending on the underlying types of soil, bedrock and other factors, buildings have the potential to sink as much as 600 millimeters, or almost two feet.
“It’s not something to panic about immediately, but there’s this ongoing process that increases the risk of inundation from flooding,” Parsons tells the Guardian’s Oliver Milman.
Human-caused global warming also compounds the risk of flooding, both by melting ice sheets and glaciers and by warming seawater, causing it to expand. Globally, sea levels have risen eight to nine inches since 1880, but in New York City, the water has climbed around that much in the last 73 years alone, per the Guardian. About three decades from now, sea levels could be an estimated 8 to 30 inches higher around New York City, according to the Verge’s Sebastián Rodríguez.
Flooding, wind and rain from Hurricane Sandy in 2012 and Hurricane Ida in 2021 caused extensive damage across New York City and, combined, these storms killed dozens of people. The city ranks third in the world for the highest amount of assets likely to be exposed to coastal flooding in the future, according to the study.
Brooklyn, Queens and the Bronx have not received as much support as Manhattan has gotten for protecting against climate disasters, writes Grist’s Lylla Younes. And people living in public housing developments are particularly vulnerable to storms.
A sinking city adds to the risk of future flooding. “Sea-level rise at New York is about 1 to 2 millimeters per year, so every millimeter of subsidence is equivalent to moving a year ahead in time with regard to rising ocean levels,” Parsons tells Live Science.
Currently, though, other effects of climate change cause more problems than flooding does, says Eddie Bautista, executive director of the New York City Environmental Justice Alliance, to Grist. For example, 350 people on average die in the city each year from heat-related causes.
“I could see why this study is a point of interest, but frankly there are far more pedestrian, daily vulnerabilities and literally people at risk of dying,” Bautista, who was not involved in the study, tells the publication. “There’s a ton more that the government could be doing to make New Yorkers more resilient to increasing impacts from climate change.”