As cities continue to encroach on agricultural and wilderness areas, many researchers, urban planners and architects are thinking of another approach: biomimicry.

L'Atelier BNP Paribas - June 2017, by Alain Clapaud

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According to figures published by the United NationsMore than 50% of humans now live in urban areas, and this will rise to 70% by 2050. In France, nearly 80% of the population already lives in cities that drain energy, food and consumer goods from hundreds of kilometres away. These sprawling cities have often been built without regard for their environment. They are devastating to biodiversity and have a large environmental footprint. In addition, they are highly vulnerable to climatic hazards. Between ever-increasing urbanisation and the effects of climate change, some believe that we now need to rethink the way our cities are designed and built. " It is time to change the paradigm and take inspiration from nature to reconnect cities to the environment  "says Olivier Floch, organiser of Biomim'Expo with the Ceebios (European Centre of Excellence in Biomimicry in Senlis) who adds " Cities must be re-vegetated, because the more people are in contact with nature, the better off they are!. Experts in what is known as biomimicry believe that nature should be copied, or rather inspired, in order to design cities that are more liveable for their inhabitants and have less environmental impact.

Biomimicry, a concept that is making a comeback

Biomimicry is an approach that has been around for a long time. Leonardo da Vinci, with his bird-inspired flying wing, is probably one of the most famous precursors of a discipline that has been brought up to date by the American biologist Janine Benyus. She emphasised the great resilience of nature in the face of the worst disasters, a model for the design of cities of the future. " It has identified between 17 and 20 biomesecozones" that are remarkable for their qualities, their resilience says Olivier Floch, who uses the example of one of these biomes, identified in India. "Every year, millions of cubic metres of water flow into this area during each monsoon. These colossal volumes of water are absorbed thanks to an incalculable number of plants that have developed a unique capacity to absorb water. Similarly, the mangroves are increasingly appearing as a natural bulwark against the rising water levels expected in the coming years. The observation of nature provides elements as to how cities can be redeveloped. Today, these biomes are being analysed in detail by researchers in order to copy or rather transpose them into cities. Wetlands planted with reeds in parks to pre-filter run-off water, green roofs, green ditches and ditches are now among the many solutions inspired by natural ecosystems. More and more mayors are turning to these nature-inspired solutions to make their cities more resilient to climate hazards.

For example, following the floods that paralysed New York after Hurricane Sandy in 2012, former New York City Mayor Michael Bloomberg created 100ResilientCitiesThis initiative brings together cities from all continents, both developed and emerging, to share experiences in areas as diverse as flood control, hurricanes, earthquakes and other natural disasters. This initiative brings together cities from all continents, both in developed and emerging countries, and promotes the sharing of experience in areas as diverse as the fight against floods, hurricanes, earthquakes, but also ageing populations, social inequalities and crime.

The architectural firm HOK has imagined restructuring the Indian city of Lavasa into 5 villages capable of accommodating between 30,000 and 50,000 inhabitants, with a limited environmental footprint (Photo credit: HOK)

Guillaume Porcheron, an expert in the sustainable development of business districts and a project manager for Versailles Grand Parc, believes that this bioinspired approach could be applied anywhere in the world: " It is necessary to study the local biotope carefully. At present, cities are increasingly designed to be above ground in relation to their natural environment. A traditional village in an oasis was built by adapting to its environment, as opposed to a city like Dubai, which is nothing more than a Manhattan in the desert. Today, this model is being reproduced all over the world, resulting in cities that consume a lot of energy and age badly in the face of the elements. For me, the ideal city is fluidity for all: the inhabitants, the plant and animal species.

While the precepts of biomimicry can be applied at the scale of eco-neighbourhoods or new cities, their implementation can also help improve the existing urban fabric. City planners are beginning to chase away the heat islands that form in areas without vegetation, in order to plant trees to limit the heat during hot spells and thus improve the well-being of local residents. It is also possible to reintroduce some biodiversity into urban areas, in particular by seeking to develop green and blue webs  in cities. Linking these grids together helps to promote biodiversity at the city level. In contrast to the mineral cities where concrete was the rule (the La Défense slab in Paris), ecologists are now pushing for the creation of brown screens, areas of permeable soil capable of absorbing rainwater. This approach is defended by Marc Barra, an ecologist at Natureparifregional nature and biodiversity agency: " Cities have a cumulative impact on nature through urbanisation, soil sealing, pollution and fragmentation. Beyond the fact that nature is not doing well, there is also a direct interest in health, well-being and quality of life, but also an economic interest. Reintegrating nature into urban development can be less expensive than a traditional development and concrete costs more than vegetation. Natureparif is conducting a study in various fields where biomimicry is applied and intends to demonstrate that, in addition to the purely ecological aspects and the well-being of inhabitants, there can be a real economic interest in implementing alternative approaches.

Architects and builders also on deck

The construction sector and architects are increasingly interested in biomimicry concepts. For example, the famous Bosco vertical " by Studio Boeri in Milan inspired the future M6B2 tower to be built in Paris in the 13th arrondissement. " When analysing these projects, it is clear that the plants and trees in the Bosco Vertical towers have to be watered with drip irrigation. Over the whole life cycle of the building, its environmental footprint remains high. These projects are interesting as demonstrators but other approaches are more effective. I have much more faith in the "25 verde" project in Turin, designed by the architect Luciano Pia, whose approach requires much less watering and maintenance. His vision is more human in terms of neighbourhood life. "

More and more architects are starting to integrate the principles of biomimicry into their work, as Nicolas Vernoux-Thélot, Architect DPLG at In Situ Architecture : " As an architect, this approach speaks to me directly because it pushes innovation with an environmental and ecological dimension. This awakening to biomimicry goes back to a meeting with a researcher in plant biology at the CNRS, Teva Vernoux. Ten years ago, we noticed that a habitat and a plant have several points in common: they are both immobile, they need natural light to function, they need water and are subject to external climatic constraints (wind, heat, cold, etc.). The parallel between plants and buildings seemed to us particularly fruitful and promising for architecture. "An R&D partnership now unites In Situ Architecture and the Reproduction and Development of Plants laboratory of the CNRS. " We have developed a bioinspired numerical model that allows one or more buildings and their various parts to be projected as densely as possible onto a site in order to optimise its exposure and passive energy inputs. The immediate gains are the energy efficiency of the buildings and the good health of the occupants. "For Nicolas Vernoux-Thélot, the implementation of the precepts of bioinspiration does not stop at the large projects resulting from public commissions or the campuses of large companies: " Even with a standard implementation and thus controlled construction costs, a building and its parts can be organized in such a way that its occupants benefit from the best sunlight and see their energy expenses decrease significantly thanks to the contributions of passive energy from the sun. Plants do it wonderfully, why not a building?  "

In addition to the pioneering architects, construction giants such as Eiffage, a member of Ceebios, are interested in biomimicry. Iswann Ali Benali, a member of EIFFAGE's Sustainable Development and Transversal Innovation Department, emphasises: " For Eiffage, biomimicry is considered to be a lever for innovation in our research on sustainable cities. In 2007, we created a foresight laboratory, called Phosphore, with the aim of imagining the city of tomorrow. This R&D project brought together a hundred or so of the group's employees. This laboratory generated a series of conceptual and technical innovations that we are trying to implement today in our operational projects, notably eco-districts or new public facilities. This is notably the case for the Euroméditerranée 2 eco-district built by Eiffage in Marseille, which is a kind of demonstrator of the concepts imagined by Phosphore.

Another area of interest to Eiffage is urban agriculture. "This is an area that is a little more mature and can be promoted in our eco-district projects," explains Iswann Ali Benali. "We have worked with Inspire Institute on its urban farm concept La Marcotte" A pedagogical project that seeks to explain how urban agriculture can be integrated with its short circuit and closed loop logic in order to enhance the value of in-situ production. Finally, Eiffage is interested in new construction processes, particularly 3D printing, which will make it possible to reproduce shapes inspired by nature, which is difficult to achieve with current construction methods. Better still, new bio-sourced materials such as straw and wood could be more widely used in construction and thus reduce the environmental footprint of new buildings. Among the research projects that have attracted Eiffage's attention are those of the XTU architectural firm. The architects Anouk Legendre and Nicolas Desmazières propose to apply facades containing microalgae to buildings. "Their algofaçade concept could soon be implemented on one of our projects in Ile de France. hopes Iswann Ali Benali. " There is a promise of thermal regulation of the building and possible use of biomass, but the problems linked to maintenance have yet to be evaluated. It is still an emerging innovation project on which we are making gradual progress. A demonstrator will make it possible to test the solution before considering its industrialisation. "

Another French start-up is also working on microalgae with the aim of depolluting city centres. Fermentalg is developing "Morris columns" with Suez, glass cylinders which, when placed in the most polluted places in large cities, trap CO2 and generate oxygen. " What is doubly interesting in this approach is that these microalgae on the one hand trap pollution, and on the other hand generate a biomass which, if properly exploited, will produce methane which will supply homes with gas or district heating. explains Olivier Floch who adds: "We are finally beginning to see waste as a resource, particularly for urban agriculture. We are thus entering a virtuous loop to move, not towards total autonomy for cities, but at least to limit the way they draw on the planet's resources.

Startups such as Glowee or Tangram Architects are exploring another direction, not to produce energy, but to light up the city of the future. Inspired by the bioluminescence of plankton, their devices could one day light our streets with a soft light that has the advantage of being less aggressive than current lighting, whose negative effects on biodiversity are now well known.

Producing energy in the heart of cities, a technological challenge

While ecologists dream of one day creating self-sufficient cities, energy remains a key issue in reducing the environmental footprint of cities. " An ecosystem is a system that lives on itself and depends only on solar energy and water "Olivier Floch points out. The problem of energy remains, as making cities self-sufficient, which alone consume 40% of the energy consumed on the planet, is a complex challenge. Researchers and architects are pursuing various avenues, including covering buildings with solar panels and wind turbines.

While there have been some attempts to integrate large wind turbines into towers in the Emirates, this seems unrealistic at present. Faced with the disadvantages of wind turbines as we know them today, researchers are considering copying the skin of whales to eliminate the noise caused by the blades, while the Moroccans of Tayer Wind propose to copy the wings of the hummingbird. Even more original, the design firm Atelier DNA has come up with the WindstalkThe windmill is an artificial reed that can generate electricity by lying down facing the wind. These quieter wind turbines may one day find their way into cities, but the initial investment is high and the commercial failure of Newwind with its urban wind turbine inspired by a tree, shows that it is still very difficult to find an economic model.

 

With its falling prices, photovoltaic technology appears to be a means of producing energy in the heart of cities, but the energy yield of panels, in the order of 24 to 25% for the most efficient, is still insufficient to meet all the needs of a city. Many experts are pinning their hopes on research into artificial photosynthesis. Imitating the photosynthesis of plants, researchers are aiming for yields close to 100%. Solar energy would then become an abundant and inexhaustible source of energy, without having to mobilise huge areas to the detriment of agriculture. Numerous research laboratories around the world are working to develop devices that will generate energy more efficiently and quickly than natural photosynthesis, but it will be many years before the technology is mastered and finally available on an industrial scale.

Nature's intelligence could even be found in the algorithms used to steer the millions of drones and autonomous cars that will roam the streets of these cities of the future. Researchers are drawing inspiration from the behaviour of schools of fish and the flight of starlings to develop algorithms for regulating urban traffic. When we know that a swarm of starlings can number several million individuals and move quickly without any of them hitting their companions, nature still has a lot to teach us.