Linda Poon is a staff writer at CityLab covering science and urban technology, including smart cities and climate change. She previously covered global health and development for NPR’s Goats and Soda blog.
Researchers studying the potential of organic materials such as seashells say future cities may emulate the ultimate designer—nature.
In her lab at Cambridge University, the bioengineer Michelle Oyen has been busy making samples of artificial bone and eggshells. The samples are only centimeters in length, but she hopes that they’ll someday make up high-rises and skyscrapers. And in that way, cities of the future will emulate one of the most ingenious designers out there: nature.
That future is still decades away, but scientists like Oyen have been studying how processes found in nature—the way leaves self-clean, for example, or the way ants stay afloat in water—can solve some of humanity’s most challenging problems, like combatting climate change and building sustainable cities.
Perhaps the way forest ecosystems thrive can teach urban planners how to build cities that can withstand extreme weather events. Or maybe architects could model skyscrapers after termites mounds in the desert, which remain cool on the inside. It all falls under an umbrella field of study known as biomimicry.
“The natural world and ecological system are maybe the best picture for what a sustainable world looks and performs like,” says Erin Rovalo, a senior principal of design at the consulting firm Biomimicry 3.8. “And if our built environment can function like these ecosystems, maybe thats the pinnacle of what sustainable design can be.”
Oyen is trying to replicate the natural formation of bones to make building materials that are more sustainable than concrete and steel. The concrete industry alone accounts for as much as 10 percent of global carbon dioxide emissions, due in part to the high temperature (more than a thousand degrees) needed to produce cement. Meanwhile, “natural materials are made at room or body temperature,” Oyen says. “They don’t need this huge amount of energy, so they’re always going to be more sustainable.”
Bones and eggshells also have the advantage of being strong: Bone is stronger than steel on a ounce-by-ounce basis, and eggshells are hard to crack open yet are also lightweight. That’s owed to their makeup of minerals and proteins. Minerals make bones stiff and resistant to breaking on a per-weight basis, while the protein makes them lightweight.
To make her samples, minerals are “templated” into commercial gelatin, a byproduct of the natural protein collagen. “We've been doing a very literal-interpretation bone biomimicry,” she says. The next step is to replace the gelatin with a polymer that is just as mechanically robust as real human bone.
As a formal field of study, biomimicry didn’t gain momentum until the 1970s, in part as a result of the environmental movement of the 1960s. Biomimetics, a branch of biomimicry that deals with applying nature’s design to fields like engineering, medicine, and materials science, spiked in popularity in the 1990s after the emergence of nanotechnology, according to Oyen. The field sometimes gets called “an emerging discipline of an ancient practice,” says Rovalo. “Humans have always looked to the natural world as a source of inspiration.”
Today, you can find examples of biomimicry in a slew of places, and in many different forms. Think of the nose design of Japan’s speedy bullet trains and how they resemble a bird’s beak. Or Antoni Gaudi’s 19th- and 20th-century buildings in Barcelona, with curvy rooftops that mimic the design of leaves and columns that look like tree trunks.
Lavasa, India, a hill city prone to monsoons, droughts, and threats of erosion, has been modeled after the ecosystem of the dense forest around it. “The design team started to ask, ‘Well how come the local ecosystem can deal with this monsoon without losing all of it soil?’” says Rovalo, whose firm worked with the design company HOK to build a community there.
So they started to study the ecosystem, and considered how rainwater-storage systems could be designed to mimic trees that take in water during the rainy season and store it for later. They also looked at designs that would help slow down the speed of rainfall—much like what leaves do in a forest.
“One of the issues in the built environment is that when the site is cleared, you're removing a lot of that vertical structure, so the first surface that [rain] hits is at maximum velocity,” she says. “The ecosystem is structured with the shrub layer, the mid-level tree layer, the canopy layer, and all those layers slow down the rain drop so that, by the time it actually hits the soil, it's very soft and absorbed very quickly.”
Indeed, in the future, biomimicry could be seen in the way houses are built or the way our transit networks are laid out. And inspiration could come from pretty much anywhere, from entire ecosystems to the individual plants and insects inside them. It could come from slime molds, or from the human body.
“We forget that we are nature, too. And that we are, just as any other species, basically biology, and have something that we can emulate and learn from,” says Arndt Pechstein, who runs Biomimicry 3.8’s sister think tank Biomimicry Germany. A neuroscientist in Berlin, Pechstein is working with researchers at the Audi Urban Future Initiative to rethink the city’s transportation network—and he’s modeling a vision after the way “cargo” moves within the cells of our bodies.
Proteins and organelles—the “cargo”—are transported via carriers called motor proteins that travel along different microtubules, or “streets.” “One motor protein is not only able to carry one specific cargo, so it can be decoupled from that cargo and can take on another,” Pechstein says. “You also have different motor proteins that can switch between different infrastructures without any waiting time or delay.”
And motor proteins communicate with one another, signaling what they’re carrying and where they need to drop it off, preventing traffic jams in our cells. That’s far more efficient than what happens in our cities, where cars sit idle most of the time and where rush hour can lead to grueling gridlock.
In studying the pattern that facilitates this sort of efficiency, Pechstein and his team redesigned the car as a concept, and dubbed it Flywheel. In this new, more modular design, the car is round and the passenger cabin seats two people. To seat more people or carry other cargo, it can merge with other vehicles to form a “train.” And instead of taking up space in the city, the team proposed an infrastructure design in which the cars—like motor proteins—can switch between being on the road and underground.
“If we can reduce the amount of transit on the surface by guiding it somewhere else, then we would dramatically reduce the noise, pollution, and space required for transport in the city,” he says.
Chances are we won’t see Pechstein’s design or Oyen’s vision for a city made of bones come to pass for several decades. While biomimicry invites scientists from all different fields, Pechstein says biomimicry hasn’t yet gone mainstream in the context of urban planning.
Biomimicry, he says, is as much about innovation as it is about changing people’s behavior. People have to want it. Oyen also acknowledges that much of her work is experimental, and there are plenty of challenges, like costs and strict building codes.
Plus, responsible implementation of nature-inspired design is a form of biomimicry in itself. “You can have disruptive change,” he says. “But in nature very often, evolution is not disruptive but more incremental.”