Monthly Archives: February 2013

So Posterous is Shutting Down

When Posterous first started, it sounded like a good idea: create new entries just by emailing. Further, their post editor was much better than WordPress’s. So I switched. The Posterous importer did a poor job on my existing posts from WordPress, but I’m not much for holding on to the past, so no big deal.

Fast forward a few years, and here we are. Good thing I never got around to shutting down my WordPress blog (SEO, what’s that?). So everything that was here is still here, and everything that is currently there, well, I’m going to have to figure out how to migrate it. I think I have to export, then import. Sigh.

Enough whining for now.


Let’s Pave Central Park

I’m serious. Let’s do it. I don’t mean pave as in turn it into a parking lot. I mean put up construction on it. And not just a little; I mean enough to replace the entire rest of Manhattan. In short, I propose a swap: Central Park turns into a megabuilding, and the rest of Manhattan — all of it — turns into parkland.

Central Park by the Numbers

Central Park is 843 acres, or about 37 million square feet. We’ll construct a building covering the whole thing, roughly 13,200 feet long, and 2,700 feet wide. Each floor of the building contains 37 million square feet, so the question is: how many floors will the building need?

Manhattan by the Numbers — Commercial Real Estate

Commercial real estate in Manhattan totals about 393 million square feet according to this real estate company, and 592 million square feet according to the Old Urbanist site, which claims to be quoting NYC property tax records — the link on the page is broken, and I wasn’t able to find a page on that listed the info that worked. so let’s (roughly) split the difference and call it 481 million, which conveniently works out to 13 floors in the mega-building.

What is Commercial Real Estate

1.6 million people live in Manhattan. They live in 850,000 dwellings, of which 77% are rentals. Assuming that apartments house the same number of people per unit as owner-occupied property, that means that about 1.2 million Manhattanites live in rental properties.

Even if the renters occupied all of the commercial real estate’s 480 milion square feet, that would be just 400 square feet per person, which seems low, even with Manhattan’s notoriously small apartments. Therefore, wikipedia’s definition of commercial real estate notwithstanding, let’s assume that the commercial space accounts for no dwellings.

Manhattan by the Numbers — Residential Space

So we have to house 1.6 million people. If we give them 700 square feet per person, that’s 1,120 million square feet. Another way to look at this is to consider the average number of people per unit, and the average size of the dwellings. 1.6 million people divided by 850,000 dwellings comes out to just under 2 people average per dwelling. Judging by Curbed’s data on apartment square footage, with two bedroom apartments averaging around 1,400 square feet, it seems 1,110 million square feet, or 30 floors, is about right.

Monolithic Stats

So the megabuilding on the former site of Central Park would take just 43 stories to encompass all of present-day Manhattan. It’s a fair trade giving up Central Park for this: Manhattan totals roughly 14,700 acres of land, of which less than 18% — 2,700 acres — is parkland. Central Park is less than a third of that, so paving it over more than reverses the ratio: it leaves 94 percent of the island as parkland.

This megabuilding would have a footprint more than 8x the current world record holder: the Boeing Everett Factory. It would of course also dwarf the world record holder for floor space, the Dubai International Airport Terminal 3, by a factor of about 130. The population density would be about 1.2 million people per square mile, significantly higher than any current human settlement, but still only about 40% of Kowloon Walled City.


With construction costs estimated at $300/square foot, the megabuilding’s 1,591 million square feet would cost $477,300,000,000. This of course doesn’t cover the cost of demolishing the rest of Manhattan and turning it into parkland.

Reality (a little bit)

Apart from the fact that this will never happen, a single monolithic building is impractical. It would leave the vast majority of the population living without a window, some of them a thousand feet from the nearest daylight.

Splitting the building into multiple smaller buildings involves either spreading out or building up. The megabuilding is only 43 stories. I’m not sure where the “crap, this building is tall” penalty kicks in on construction costs, but it seems safe to go to 66 stories, which would free up one-third of the land. If the megabuilding were split into 270 66-story buildings, each 300 feet square, there would be almost 70 feet between the buildings, still all within the former footprint of Central Park. That’s not ideal, but everyone gets daylight.

But of course the buildings wouldn’t all have to fit in Central Park. In fact, they could be built around it instead. Going out to the rivers and 15 blocks north and south of the park yields about 4,300 acres, which would allow each of those 270 buildings to occupy 16 acres, meaning there would be over 500 feet between any two buildings — almost everyone would have a view of the park or the rivers.


This Manhattan would have no need of cars, or roads, or parking structures, or cabs, or even buses. Mass transit, already a hallmark of the city, would be simple and effective. Arranging a few circular subway routes around the park, with enclosed moving walkways to reach them, would be simple. Likewise, enclosed bike routes would be easy to design, and biking from anywhere to anywhere in the new city would be no more than about three mles.

Energy efficiency would be significantly improved. (New York is already one of the most energy-efficient cities in the U.S.)

Infrastructure would be incredibly simpler. As one example, how hard would it be to provide high-speed wireless internet throughout those 270 buildings? Likewise for water, trash, sewer, delivery services, and more. It seems reasonable to assume significant consolidation of other services, like groceries, restaurants, doctors, hospitals, fire and police, etc.

No one would have to be exposed to the weather unless they wanted to be. Adapting the current subway system would be possible, as would building above-ground enclosed travel spaces, with windows for people to safely enjoy viewing the snow in winter.

All the economic and social benefits described by Edward Glaeser in Triumph of the City, intensified because of the extreme density of the city.

Manhattan’s daytime population is almost 4 million. An incredible number of people commute to the island every day. Up the building count to around 500 and all of those people, along with their families, could live in Manhattan and still have 80% of the island left for parkland.

So who’s with me? Let’s pave Central Park.