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What Would It Take to Turn New York into a Megacity?

Read More: http://io9.com/what-would-it-take-to...52944/+megneal

Something bizarre happened overnight: New York City's population grew to the size of Shanghai's, swelling from 8 million people to 24 million. It's like a natural disaster, but this tidal surge is made of human needs. Here's how we'll rebuild the city to make room for them all.

- Though the rapid change is fantastical, the transformation isn't: New York's population is likely to grow by almost this much by the end of the century. All over the world, cities are making the transition from large cities to megacities of over 15 million people. So our thought experiment isn't about wanting to escape to the city planet Coruscant from Star Wars. It offers a glimpse of what the largest city in North America might actually look like in 2114.

- New York City is already one of the most densely-packed urban spaces in the world, with 10,724 people on average per square kilometer. To triple the living spaces here, we'll need to build up — but we'll also need to build between. The city could no longer afford to devote so much street space to the products of an already-shaky auto industry, and the city's grid would change immeasurably. So would the laws that govern it.

- For efficiency's sake, Manhattan would have to retain a couple of the major avenues like Fifth, which cuts through the center of the island. But it would be reserved for trucks delivering food — or taking garbage out. Other streets would be for licensed taxis and services like Uber, while cars belonging to individuals might be routed to the edges of island, or to other boroughs entirely. Getting around in Manhattan would mean taking public transit, or paying dearly to get an Uber.

- At the same time, there would be a flowering of pedestrian walkways like Sixth and a Half Avenue, which tunnels through the skyscrapers of midtown in between Sixth and Seventh Aves. As more skyscrapers grew, walkways would also take to the skies in bridges between buildings. To keep the ground-level streets less congested, pedestrians would be invited to walk Broadway from the air, hustling from building to building via a growing network of architectural tissues that would nourish a new sidewalk culture fifteen stories off the ground.

- Some of these elevated sidewalks would be classic New York, complete with tar-gummed concrete and jagged nubs of rusted rebar poking out at odd angles. But others would look like high-tech works of art. Architectural futurist Geoff Manaugh, proprietor of BLDG BLOG, describes megacity New York like this: --- A world of Judge Dredd-like megastructures, land bridges across rivers, and pedestrianized super-corridors extending through the labyrinthine hearts of financial complexes ... carving new routes through the deep interiors of buildings, without a car in sight.

- Columbia professor of urban development Kate Ascher (author of The Works) thinks the megacity of New York would have to spread into transit corridors, with construction booming (and prices skyrocketing) near train stations that can take commuters into the city center. Many of these new nodes would also be high-density areas with little area for automobiles and elevated sidewalks shuttling commuters through their vertical towers.

- Even if we can create our own version of Pearl River Delta's city clusters along the eastern seaboard, we may still be looking at an urban disaster. New York City produces about 37,000 tons of waste per day, all of which has to be trucked out of the city, often for hundreds of miles, before finding its final resting stop in landfill. Certainly the city might begin recycling more if the population boomed, but we'd still be looking at about three times the amount of waste — so, we can assume that our 24 million New Yorkers will be pumping out 111,000 tons of garbage every day. The problem wouldn't be the garbage piles, but the infrastructure needed to move them around.

- To find a new home for the landfill, the the city might rejuvenate a 1934 plan for expansion, which would have topped up the Hudson River with landfill. At the same time, the city might also explore radical new methods for garbage disposal, including converting it into an energy source or biochar for fertilizer. The edges of the city might be ringed with enormous biochar plants that heat up all the waste until it's converted into a coal-like substance whose byproducts include carbon neutral fuels.

- Most of New York's food arrives the same way garbage escapes: on trucks. There's been a lot of excitement about building vertical farms within Manhattan, or skyscraper greenhouses packed with enough crops to feed the whole city. But there is a lot of controversy over whether such structures would save money and energy. In the more populated future, we're probably looking at bringing in food on trucks powered by alterantive fuels rather than giant hydroponic farms towering over Union Square.

- With so many people depending on imported food, however, food security expert Evan Fraser worries that the new megacity would be even less prepared for disasters than it is now. Where would the city store emergency food supplies for 24 million New Yorkers if a natural disaster were to take down the power grid or blanket the midwest in ash? "New York City is dependent on a global supply chain for its food," Fraser said. "We have no data on what kinds of food stores exist because the government doesn't store food anymore. And food companies like Walmart or Monsanto won't tell us what they have stored. It's a proprietary secret."

- Unlike many cities that are struggling under the weight of population expansions, New York has one precious resource in abundance. Partly due to smart early planning, and partly due to luck of geography, the city has many sources of drinking water, including the Catskills and Croton watersheds north of the city. Clean water from these areas tumbles into the city through viaducts, propelled by nothing more than gravity.

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Shape-shifting elevated sidewalk concept, by sanzpont