New York City is sinking -- in some neighborhoods more than others, study finds

NEW YORK -- The Big Apple is on its way to a big sink. 

A new study published this month in the journal "Earth's Future" shows New York City is slowly sinking, but there is no need to invest in a life preserver right away. It will likely take hundreds of years before New York is looking more like Venice. 

"It's inevitable," said Tom Parsons, of the U.S. Geological Survey. "The ground is going down, and the water's coming up. At some point, those two levels will meet but I just am not able to give you a date." 

Parsons research shows the city is sinking 1-to-2 millimeters per year. He says the main cause goes back thousands of years. 

"The dominant cause is the glacial effect from the last ice age that pushed down the mid-continent and caused a bulge along the eastern coastline. And when the ice melted, that reversed everything," said Parsons. 

Parsons says the sink is a natural process, happening everywhere ground is compressed. But his study shows the massive weight of the city itself is hurrying things along: Skyscrapers, homes, asphalt and humanity.  

"We have different kinds of soils across New York City, including artificial fill that can that was put in to enhance some of the land areas and that can sink just under its own weight because it's so poorly consolidated," said Parsons. "And if you build on that, of course, that it exacerbates it." 

The rate of compression varies throughout the city. The study revealed while Midtown, Manhattan skyscrapers are built mostly on rocks -- meaning, it compresses more slowly -- some parts of Brooklyn, Queens and downtown Manhattan are on looser soil and sinking faster. 

"The weight of the buildings themselves, the force that they applied to the ground and caused further subsidies," said Parsons. 

More than one million buildings are spread across the city's five boroughs. Researchers estimate the structures add up to 1.7 trillion tons of concrete, metal and glass.