The urban revolution of the Anthropocene is not just remarkable in its scale, but also in the way cities are evolving. They are getting smarter.
One of the problems with city infrastructure and architecture is that they are designed without much flexibility. They need to meet certain structural and safety standards, to withstand worst-case weather and seismic challenges, for example, but not necessarily to operate effectively in the majority of circumstances. For buildings like lighthouses, this may not be a concern, but for most buildings and urban spaces, liveability under a range of weather conditions is also important. We adapt our clothing – why not our buildings?
The Media-TIC building in Barcelona, Spain is one example of what’s possible. It has been designed with an inflatable plastic (ETFE) skin that is regulated by a solar-powered automatic digital light sensor. As the sun changes throughout the day, different air chambers in the skin expand or contract. Compared to glass, ETFE film is 1% the weight, transmits more light and costs up to 70% less to install. It's also resilient (able to bear 400 times its own weight, self-cleaning (due to its non-stick surface) and recyclable. The responsive skin allows light to filter through, but shades people inside from direct UV rays by 85%. Other buildings are incorporating light-reactive glass in a similar way to that used in sunglasses, to reduce heat and glare during hotter parts of the day (reducing the need for air-conditioning), while allowing the maximum light through during other parts of the day (reducing the need for electric lighting). Automatic light-responsive sunshades play a similar role in other buildings.
Sensors are also used to regulate energy and resources inside the building, operating lights when movement is detected, for example, or sensing when to divert people, water or heating. For example, if a regularly trodden route of carpet starts wearing out, subtle lighting changes can encourage people to walk a fresh route, or if activity is only detected in a portion of an office space, heating can be restricted to that area.
Architects are also looking at incorporating responsive, living materials into traditional buildings to make them more environmentally sustainable and adaptive. Many now have green roofs and walls, which filter air, keep the buildings cool, conserve water, invite biodiversity and look attractive. But what about making structures themselves out of living materials? Engineers have created self-repairing concrete that uses sunlight, or that is impregnated with bacteria. Any cracks that appear in the concrete and allow water in will activate the bacteria, lying dormant in nutrient-rich capsules, and the limestone released fills the cracks.
Other proposals include growing structural parts of buildings and street furniture around frames, using synthetic biology to prompt cells to produce useful materials. One futurist architect believes that the sinking city of Venice could be saved by programming cells to create a limestone reef underneath it. Other designers imagine living, responsive buildings that act as an immersive interactive installation, able to move and breathe alongside their occupants.
Even if these ideas seem unrealistic, what’s certain is that engineers will be using ideas from biology and incorporating self-repair, light and heat response, and other adaptive features into the materials and structures of future cities.
Anthropocene citizens are likely to generate their own supplies of everything from water to electricity and fuels to supplement increasingly expensive municipal provisions as resources become scarcer. For example, many buildings will passively harvest their own rainwater, householders will filter, store and reuse “grey water” from showers and sinks for toilet flushing and watering the garden. Water conservation will become commonplace and regulatory in cities around the world, as it already is in arid countries like Australia.