How to Death-Proof the Cities of the Future

To safeguard the future of our increasingly urban species, our cities must be sturdier, healthier and more alive.

By Annalee Newitz|Tuesday, May 28, 2013
death-proof-city
death-proof-city

An artist’s rendering of protocell reefs in Venice, Italy: Researchers believe the bioengineered organisms could stabilize the city by forming colonies around its water-logged, rotting infrastructure.

Christian Kerrigan

Cities are not static objects to be feared or admired, but are instead a living process that residents are changing all the time. Given how much bigger and more common cities are likely to become over the next century, we’ll need to change them even further. 

Using predictive models from engineering and public health, designers will plan safer, healthier cities that could allow us to survive natural disasters, pandemics and even a radiation calamity that drives us underground.

But there is an even more radical way we’ll transform our cities. Over the next two centuries, we’ll probably convert urban spaces into biological organisms. By doing this, we will make ourselves ready to prevent two of the biggest threats to human existence: starvation and environmental destruction. 

Eventually this biological transformation might result in cities unlike any that have existed before. The biological city could provide us with food and energy security for millennia to come.

bacteria-lattice
bacteria-lattice

Bioengineers try to mimic nature and then improve it: Bacteria grown on a lattice could be a potential building material.

David Benjamin

Grow a Living City

Cities might become biological entities, walls hung with curtains of algae that glow at night and sequester carbon, and floors made from tweaked cellular material that strengthens like bones as we walk on it. 

New York architect David Benjamin is part of a new generation of urban designers who collaborate with biologists to create building materials of the future. I met him in Studio-X, a branch of Columbia’s Graduate School of Architecture, Planning and Preservation. The studio is located in a bare-bones, whitewashed workspace below Greenwich Village. 

Students focused on monitors full of three-dimensional renderings of buildings, or sketched at drafting tables between cement columns. It looked like the kind of place that could, in 50 years, be sprouting a layer of grass — or something much stranger than that — from its walls.

Benjamin described the shift to biological cities using quick, precise gestures that reminded me of someone penciling lines on a blueprint. “It might look the way it looks now,” he admitted. “The city could be made with bioplastics instead of petroleum plastics, but it would look very similar. A machine for making bioplastics and other materials from genetically modified organisms would exist in factories the way they do today for making medicine and biofuels.”

So the plastic fittings around windows would be manufactured from modified bacteria rather than fossil fuels, but as a city dweller you’d notice little difference. Benjamin and a group of other architects and biologists have worked with Autodesk, the company that makes the popular AutoCAD software many architects use to design 3-D buildings, to create BioCAD, a mock-up of AutoCAD for biological designs. 

Pulling out his laptop, Benjamin showed me a demonstration of the biological design software interface. The designer can select biological materials with different properties, like flexibility or strength. Having chosen those, the designer directs the program to create structures that look like marble cake, a multicolored swirl of substances combined into a single material that gives in the right places and holds steady in others. 

Over time, these living cities would start to look different, too. They’d be transformed by synthetic biology, a young field of engineering that crafts building materials from DNA and cells rather than more traditional biological materials, like trees. 

Benjamin described a recent synthetic biology product called BacillaFilla, created by a group of college students in England. The students engineered a common strain of bacteria to extrude a combination of glue and calcium when put into contact with concrete. They applied the bacterial goo to cracks in concrete, and over time it filled the cracks completely and then died, leaving behind a fibrous, strong substance that has the same strength as concrete. 

The students described BacillaFilla as the first step toward “self-healing concrete,” and their efforts are just one among many to create biological substances that could heal ship hulls, metal girders and more. Although still in the development phase, these materials could be commercially available within the next decade. 

Extrapolating from this development in synthetic biology, Benjamin mused, “Maybe you could program a seed to grow into a house. Or maybe cities would be so in tune with ecosystems that they would grow over time and then decay over time, too.” 

Synthetic biology might also help solve one of the biggest problems with new buildings, which is water leakage. Architects could design a building that is semipermeable, with membranes that allow the circulation of air and water at various times. It’s easy to imagine a future architect fashioning just such a thing with BioCAD, with patches of permeable materials built right into the fabric of the walls. The water could be purified and used, and the air could become part of a natural cooling or heating system.

Xylem-Cell
Xylem-Cell
An artichoke’s magnified and 3-D- printed xylem cell could inspire new structural designs.
David Benjamin

This building might also use computer networks to monitor its community of local buildings to figure out when to gather solar energy and send it to the grid to share, as well as when to lower louvers to keep residents cool. 

“I sometimes imagine urban landscapes that are integrated into their ecosystems with a combination of vegetation and constructed materials,” Benjamin said. “They look almost like ruins in the jungle, but they’re actually fully functional, occupied cities.”

Benjamin’s visions of the future end where his fellow synthetic biology designer Rachel Armstrong’s begin. Armstrong, a designer based in London, is an outspoken advocate for what she calls “the living city,” or urban structures that she told me we’d create in the same way we cook or garden. 

We met in a cafe in the heart of London, overlooking a busy street near Tottenham Court Road, and almost immediately Armstrong was imagining how she’d rebuild the city around us. 

“You’d have surfaces creeping down buildings like icing. Strange, colored panels would glow through windows at night, and you’d have bioluminescent streetlights. Bridges will light up when we step on them.” She paused, but continued staring outside, deep in thought. “We’d keep the bones of buildings steel and concrete, but rewrap those spaces with increasingly more biological facades. Some will be porous and attract water; others will process human waste. Mold won’t be something you clean off a surface but will be something you garden.” 

Armstrong’s vision sounds like science fiction, but she’s just describing what tomorrow’s air and water filtration systems might look like. Instead of filling our walls with rusting pipes and ducts, we’d swathe our buildings in engineered bacteria and mold to process our waste, generate energy and even purify our water. 

Armstrong is fascinated by bacteria and mold, which she and other synthetic biology designers view as the building blocks of future cities. “We are full of microbes,” she asserted firmly. “Maybe instead of using environmental poisons to create healthier environments inside, we should be using probiotics.” 

Glowing bacteria could live in our ceilings, lighting up as the sun goes down. Other bacteria might purify the air, scrubbing out carbon. Every future urban home would be equipped with algae bioreactors for both fuel and food.

Such a future may be closer than you think. Recently, Armstrong worked with a group of biologists and designers who hope to use experimental protocells — basically, a few chemicals wrapped in a membrane — in a project that could prevent Venice from sinking into the water. The city was built on a marsh, and water periodically bubbles up, rotting the infrastructure over time. 

Protocells are semibiological and can be designed to carry out very simple chemical processes. In Venice, engineers would release protocells into the water. Designed to prefer darkness, the protocells would head for the rotting pilings beneath the city’s dwellings. Once attached to the wood, the protocells would slowly undergo a chemical transformation, turning their flexible membranes into calcium shells. 

Over time, these shells would form the core of a new artificial reef. As wildlife discovered the calcium deposits, a natural reef would form, and the city’s shaky foundations would become a stable ecosystem. Already, Armstrong and her group have had some success creating small-scale versions of the protocell reef in the lab, and they’re moving on to experiments in controlled natural areas. 

If our cities do evolve to be more like biological organisms and ecosystems, it could change the way communities form within their walls. “We might start to experience the city as something we have to take care of the way we take care of our bodies,” Armstrong suggested. 

In a biological city, using a toxic chemical in your kitchen might cause your algae lights to die. “We’ll take more care of the city because we feel its injuries more deeply.” It’s possible this could generate a sense of collective responsibility for our buildings and avenues. Neighbors would tend their buildings together, trading recipes for making fuel the way people today trade recipes for holiday cakes. 

Of course, it’s impossible to predict what the consequences would be for people in cities whose buildings were half-alive. Armstrong is willing to admit her ideas are utopian, and that’s the point. “You need something to aim at,” she said with a smile.

skyscraper-farm
skyscraper-farm

Solar-powered skyscraper farms — such as this artist's rendering from Dickson Despommier's The Vertical Farm — could feed our growing cities of the future.

Blake Kurasek

Feed a Hungry City

In his book The Vertical Farm, Columbia environmental health professor Dickson Despommier argues that cities of the future might feed themselves by creating farms inside enormous, glass-walled skyscrapers where every floor is a solar-powered greenhouse. All the water in these skyscraper farms would be recycled, and the structures themselves would be designed to be carbon neutral. 

While critics question whether it would be possible to heat, power, light and tend skyscraper farms without wasting a lot of energy, Despommier’s thought experiment is a good one. We are going to need ways to produce enormous amounts of food in cities, often indoors, and trying to figure out how we’d do that in a skyscraper — or an underground cavern, for that matter — is a step in the right direction.

Our future buildings may be sprouting gardens on the outside, too. A popular way to transform cities in Germany is by building green roofs, which are basically special systems designed to convert rooftops into gardens. 

This isn’t just a matter of heaping some dirt up and throwing seeds on it. Green roofs are a complex system of layers designed to protect the roof, absorb water and hold soil in place. Some studies have shown that green roofs help cut energy costs by keeping homes cooler in the summer months. They also reduce storm water runoff, which is a huge issue in cities. 

Because most cities are covered in nonporous, nonabsorbent surfaces, all the grime, toxins and trash in the city are washed out by rainwater during storms — and washed into the nearby waterways, farms and oceans. Having a roof that can absorb rainwater does a tremendous amount of good for the local environment and cuts costs related to water purification and treatment.

Bringing natural environments into cities isn’t just about feeding ourselves. It’s also about figuring out how to manage our energy consumption using tricks borrowed from nature, such as growing shade plants on our roofs, which can help cut energy costs in summer. Natural ecosystems conserve energy remarkably well.

public-health-surveillance
public-health-surveillance
Local and state-based public health surveillance networks track flulike symptoms and are often the first to see outbreaks with pandemic potential.
Lloyd Fox/Baltimore Sun

Ensure a Healthy City

Although the Centers for Disease Control and Prevention (CDC) and the World Health Organization are the organizations we think of first when it comes to containing a pandemic, the greatest asset in any surveillance network is always going to be your local health department, where the signs of an outbreak are going to be registered first. 

David Blythe manages health surveillance for the Maryland public health department, which coordinates with dozens of regional health departments to track what are called “flulike symptoms.” Blythe said that one of the main ways the CDC tracks potential outbreaks is with a network called ILINet (for influenza-like illness surveillance program), a volunteer effort where local doctors, nurses and other health care workers report any infectious, flulike symptoms they see cropping up in patients. 

It’s key that they report symptoms rather than try to diagnose what they see, since one of the main things ILINet is designed to catch is a new, deadly flu strain. If that happens, the collection of symptoms may not match any known illness. Every week, analysts with ILINet pore over the data, looking for suspicious patterns. 

What’s crucial here is that this health surveillance is happening on a city-by-city basis. When the next big pandemic starts brewing, city health-care workers are going to notice it long before national and international agencies do.

To supplement the work of ILINet, Maryland also has a network of volunteer labs that send samples of flu strains they’ve collected to the state health department for testing on a regular basis. “This is a lab that’s just designed for surveillance,” Blythe said. “We can do the testing that tells us whether it’s AH3 or N1, and we can determine if it’s a pandemic strain.”

subterranean-city
subterranean-city

Subterranean urban centers of the future could integrate natural light and flowing water to simulate surface living, as in this artist’s rendering.

Andrew Kudless/Matsys Design

Build a Subterranean City

If we’re going to survive nuclear war, meteor strike or radiation event, there is no doubt we’ll have to live underground for months or even years as the planet recovers. The good news is that 3 feet of packed dirt over your head can significantly reduce the intensity of radiation, and a layer of cement can provide more safety still. 

We have the engineering ability to create radiation-shielded cities by going underground. The question is how we would live there. 

Concordia University city planning professor John Zacharias has studied several underground cities, especially in Japan and China, and told me that the biggest challenge is psychological. Studies of people who work all day in underground space without any access to the outside show rising stress levels. 

“It’s not dramatic, but is measurable,” he said. “Going down very deep is also something people don’t like.” The new Oedo train line in Tokyo is 180 feet below the surface, and Zacharias said people tend to avoid it in favor of an overcrowded line it was supposed to relieve. 

In Finland and Sweden, where underground buildings are common, studies have shown that people are disturbed by the process of descending into the Earth, and that they complain of the monotony in subterranean buildings. 

The solution, argue civil engineers John Carmody and Raymond Sterling in their underground engineer omnibus, Underground Space Design, is to make sure underground spaces are “stimulating, varied environments” that give the impression of spaciousness and daylight. 

Ideally, different areas of the city would have dramatically different designs to give the feeling of neighborhoods and landmarks that we use above ground to figure out where we are. Privacy will also be a premium in spaces like these where people have a tendency to feel trapped. 

As we turn our tunnels into our homes, we’ll want to remember to create places to be alone, as well as vast, high-ceiling rooms that will make us feel like we’re outdoors even if we aren’t.

piston-versus-concrete-column
piston-versus-concrete-column

It's massive piston vs. concrete column at UC Berkeley's Earthquake Simulator Laboratory.

Peg Skorpinski

Engineer an Unshakable City

I met UC Berkeley civil engineer Shakhzod Takhirov inside a three-story warehouse that’s home to the university’s Earthquake Simulator Laboratory. Located in the city of Richmond, Calif., the lab is easily identified by its proximity to piles of shattered wood beams, twisted girders and giant cracked columns of concrete. 

But this was no junkyard. As I wandered through the rubble, I noticed that every crack and break had been carefully labeled with measurements in permanent marker. 

The instruments of destruction that created these piles occupy most of the lab. Towering over my head as I walked in was a 65-foot-tall steel piston that can deliver up to 4 million pounds of compression to whatever structure or material is unlucky enough to be in its grip. 

Behind the mega-piston, I could see that day’s main experiment. Lab technicians had built a life-size frame for a single-story building in the middle of the warehouse-size space. Attached to the frame were huge, hydraulic motors: actuators that looked a bit like pared-down robot arms, braced between the building and a strong, concrete wall and controlled by researchers in a room packed with computers. 

With the press of a button, the engineers could deliver small, precise earthquakes to the building — or bone-rattlingly big ones. Sensors on the structure could measure every deformation and shake that propagated through it. 

Takhirov’s colleagues and students used their giant actuators to imitate how earthquake forces would deform the building, but they were doing it in slow motion. There was none of the violent motion you would see in an earthquake, but those robot arms carried the same force as a quake would. 

“We do this so we can look at each step,” Takhirov said. The researchers can also create a “hybrid simulation” that combines a mathematical model of a building with the physical object in the lab. The experiment that I was watching with the one-story building turned out to be a model of a two-story building — the second story existed only in software. 

We know enough about earthquake engineering at this point that we can actually extrapolate how a second story might behave based on what the first story does when it is slowly crushed by giant motors. Hybrid simulations make it easier for engineers to calculate how city buildings might respond in a quake, even if they aren’t able to build an entire 50-story building and wiggle it. 

Excerpted from SCATTER, ADAPT, AND REMEMBER: How Humans Will Survive a Mass Extinction by Annalee Newitz. Copyright © 2013 by Annalee Newitz. Published by arrangement with Doubleday, an imprint of The Knopf Doubleday Publishing Group, a division of Random House, Inc. and Penguin Group (Canada), a division of Pearson Canada, Inc.

[This article originally appeared in print as "How to Death-Proof a City."]

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