Just look at it.

A monument to human achievement.

Over 1.5 trillion pounds of modern megaliths, scratching at the heavens.

A metropolis ever-soaring.

Up.

Up.

Up.

And then one day you find out, it's literally going down.

New York City is sinking.

And all that high-up human achievement isn't helping.

The city is sinking under its own weight.

Researchers at the United States Geological Survey and the University of Rhode Island calculated the weight of all the city's buildings and found that it is contributing to what they call subsidence.

There's more than a million buildings in the city.

So it's a massive amount of weight.

Engineers know that each building they construct settles into the earth over time.

How much it settles depends on what's underneath.

It's going to be really important for us to learn more about the natural geology underlying New York City, which we tend to forget because it's so paved over.

As you get down into lower Manhattan, there's a lot of fill where people have essentially just dumped stuff.

And then they're like, hey, now we've got land here, let's build on it.

And those areas are really susceptible to sinking.

All told, the skyscrapers are not the main culprit.

The bigger truth is that New York is sinking for a variety of reasons.

Turns out there are heavier things than buildings.

They're called glaciers.

The majority of the sinking is caused by GIA.

So it's Glacier Isostatic Adjustment.

During the last glacial maximum, an ice sheet miles thick covered the land north of New York.

And that held it down.

And when it held it down, actually the land to the south of the ice sheet bulged up.

It's a little bit like a barge that was loaded on one side and we are on the upside.

And when you remove the weight of the glaciers... the barge gets unloaded, comes up, and New York goes down.

Of course, the ground going down... is not the only thing to worry about here.

The story with the sinking of Manhattan from the weight of the building is a little bit like a monkey compared to the elephant in the room, which is sea level rise combined with storm surges.

The term we use is relative sea level rise.

So you have to account everything, including how fast the water is going up and also whether your land is going up or down.

Add the average sea level rise of 3 to 4 millimeters per year to New York's subsidence of 1 to 2 millimeters per year, and you start to get a serious problem.

So how can we stop the sinking?

In New York, there's probably not much that can be done to stop the sinking.

Cool.

Then how do we adapt?

New York needs to turn itself into a sponge.

What we need to make sure is that every piece of infrastructure can hold and absorb water so our 100-year sewer system can catch up and process it.

There's a lot of coastal infrastructure projects, such as one called the Big U, which wraps around all of Manhattan, kind of in a U shape.

And that is under construction right now.

And there is something the buildings can do.

Buildings are actually our primary source of greenhouse gas emissions.

So 70% of our heat traffic gas emissions in New York City come from the buildings themselves.

There's a lot of new technologies that we could start to adapt very rapidly to reduce the emissions from our buildings here in New York City and serve as a model for cities all over the globe.

But at some point, the situation may call for more drastic action.

Eventually, you have to retreat to higher ground.

Luckily, New York City has high topography.

We have to move together a little bit, and we have to make room for water.