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Environmental, economic, and social equilibrium are the three pillars of a sustainable city. Pie in the sky? Not really. Across the planet, traditional cities are gradually upping their sustainable credentials. From Vancouver in Canada to Montevideo in Uruguay, Reykjavik in Iceland, Portland in the United States, Cape Town in South Africa, and the densely populated territory of Hong Kong in China, efforts are starting to yield results.
But in practice, what is a sustainable city? A sustainable city recalibrates its development policies to give priority to low-energy housing, renatures its environment, limits urban sprawl, and encourages a mix of housing, services and shops, density, and micromobility. Able to stand the test of time, it can resist future extreme weather events. A convenient city, its residents enjoy a decent quality of life, and it doesn’t pass on costs and problems to future generations. A sustainable city is also a metropolis where everyone works together again for the future.
Some people may also see this ideal city as a threat to their routines, personal comfort, and freedoms. They fear the limitations imposed by the multiple obligations they need to fulfil in order to achieve its “sustainable and responsible” goals. Are they right to be afraid? To set the record straight, we asked Philippe Outrequin, a specialist in urban sustainable development and the author of multiple works on the subject*, to help us debunk 14 popular beliefs and misconceptions about the sustainable city.
A sustainable city is not a more expensive city. Or it shouldn’t be, because a sustainable city should primarily be an inclusive city, somewhere everyone can live, however much they earn. It takes money to renovate and build, of course, but one of its main goals is to help us use less energy and fewer resources, travel less, produce less waste and therefore, in the long run, be more accessible, because by saving energy, everyone is more comfortable for less. This is the point made Pierre-André de Chalendar, Chairman and CEO of Saint-Gobain, in his latest book, The Urban Challenge. Reviving the desire to live in a city. “Today, there is no proper choice but to think sustainable from the outset - this will cost a little more at the beginning but, when the life expectation and running costs of a building are properly assessed, the benefits are obvious.”
The idea of a sustainable city accessible to everyone applies to people around of the world - not just to a privileged few in the West. “In many developing countries we are seeing the emergence of a middle class that is not satisfied with a basic housing standard and is looking forward to a dwelling capable of meeting comfort standards, far above the low cost that one would presume," explains Pierre-André de Chalendar. Over the last four years, the urban community of Douala, a highly dense, sprawling city in Cameroon, has run a sustainable redevelopment pilot in the district of Makèpè Missokè. The aim is to identify best practices to apply across the agglomeration in order to build a resilient city. But a sustainable city is also a “social” city. This is why the Brazilian city of Curitiba, where residents can trade waste for bus tickets and food, for example, has pursued a policy as “green” as it is social since the 1970s.
A sustainable city contains its geographical sprawl and seeks to “renature” itself. This means densifying already inhabited areas and building denser homes. But denser does not necessarily mean higher. Densifying buildings is more about collective solutions, like small- and medium-height buildings with terraces, balconies, or modest gardens. Houses for three or four families - a familiar sight in Germany - are much more practical and denser than single-family homes on fenced plots.
It’s an understandable assumption that, for a city to be sustainable, homes have to be smaller, to save on materials and energy. But not always. We can be reasonable and live in a house of a size adapted to our family and its needs, without compromising on our comfort. Especially since the impact of highly energy-efficient buildings can be positive.
On the other hand, yes, in a sustainable city, there’s more emphasis on sharing and developing common service spaces, such as meeting spaces, laundry rooms, shared guest rooms, etc. This may seem restrictive, but it saves energy... and money (you access and use the spaces only when you need them, and share maintenance costs), and frees up space at home for personal belongings, for example.
Construction is central to the sustainable city because a growing population boosts demand for housing. But because we need to grow the sustainability of existing cities, which are already built and lived in and occupy a finite amount of space, the most viable solution to replace old housing stock (some old properties are heat sieves) is to renovate it. Interviewed by Pierre-André de Chalendar for his book, the urban planner and teacher Sylvain Grisot discusses his latest concept: circular urban planning. “The idea is to apply the principles of the circular economy (a model of production and consumption which promotes sharing, leasing, refurbishing and re-cycling) to produce a flexible city, capable of continuously adapting to changing needs and which optimises the use of already-available artificial land***”.
More and more people agree that building at all costs is no longer a solution. In 2011, many European countries committed themselves to the NNLT (No Net Land Take) scheme to stop the loss of undeveloped land to human-developed land by 2050 and to compensate for any new land taken by “denaturalizing” equivalent areas. To achieve No Net Land Take we therefore need to build “the city within the city”, without occupying the agricultural land that feeds us. The result is an improved, modified, renovated and more efficient urban area... without the sprawl.
The terms “natural” and “bio-based” are misleading when it comes to materials because they give the impression they’re sustainable and good for our health and environment. But this is not always the case. Lead is a natural material, for example. A bio-based material may also contain toxic additives. It’s not as simple as it seems!
That said, some natural materials, such as raw earth, in use for thousands of years, offer potential avenues for sustainable construction and have begun to find favor among builders.
The sustainable city, ultimately a showcase for good practices, is more likely to focus on renewable or recycled materials, or even non-renewable but recyclable materials. Materials requiring too much energy to transform, or which are too polluting to transport are excluded.
The opposite is true. The sustainable city is designed to guarantee our thermal comfort, so we are neither too hot nor too cold. How? Because in the sustainable city, engineers develop solutions to this problem and old buildings are renovated using materials that guarantee their heat efficiency. New technology makes it easier to recover heat from wastewater for heating in winter and cooling in summer. At the same time, this system “reduces CO2 emissions - from heating or cooling buildings - by 30 to 70% and promotes energy-efficient heating”**. The result is energy-efficient buildings, properly insulated and designed to store heat when it is cold and optimize cooling by wind and at night in summer. Some can even produce their own renewable energy: positive energy buildings.
But again, it’s not about banning things. Everyone needs to travel as they go about their daily business. An artisan who cannot use his or her vehicle is placed at a disadvantage. The aim is rather to reduce the “need” to travel, especially for short journeys. Emerging solutions include functional diversity - locating homes, facilities such as schools, administrative buildings, health centers, and shops close together - and the development of short supply chains to limit the transportation of goods. Fostering digital technology to promote remote working, e-commerce, e-health, and the like, is another way to reduce the need for transport. Finally, the sustainable city makes it easier to adopt and use micromobility rather than cars for some journeys.
We must change. Fostering the development of sustainable cities is a long-term process. Although the transition shouldn’t punish people living in urban areas by imposing a series of restrictions on them, we still need to find ways to reduce waste and unnecessary travel. Because we simply cannot sustain the “Western” way of life as it exists today. But not everything rests on the shoulders of residents. Maintaining the same standard of living with fewer resources will require a change in the way markets work and political will to push through rules and regulations, provide financial support, and set up an appropriate system of taxation or tax incentives. In short, a comprehensive policy driven by the community.
Although a more sustainable movement can be top-down, through organizations, regulations, legislation, and the like, we still need individual initiatives to make it work. Tontines, peer-to-peer organizations that save for common projects in Africa, participatory housing in Norway, where residents share a maximum of services to reduce costs, and even small-farming organizations in France, are all initiatives led by individuals. But each one, in its own way, helps reduce individualism and create a city of solidarity and collective intelligence - the driving force behind the sustainable city.
“Degrowth implies a drop in the economic wealth of a territory, or even the disappearance of a civilization”, explains Philippe Outrequin. But this is not what the development of a sustainable city requires. It involves a different kind of growth. A type of growth in which non-renewable resources, the earth and nature increase in value. It’s about ending the financialization of the economy and the return of a people-centered economy.
Since a city cannot produce everything it needs to function, the pursuit of self-sufficiency is a path to degrowth. It also fosters distrust, whereas sustainable cities only make sense when people cooperate. The “sustainability” of a city may make it appealing and different, but there must be a consistency of solidarity with the surrounding environment.
But let's be honest: this is already the case in countless cities around the world, “sustainable” or not. Nevertheless, Philippe Outrequin believes that we should not focus on the “control” that results from it - which can sound alarming - but rather on the opportunity offered by these new technologies, which can help raise our awareness of our actions and their consequences.
In 2009, for example, San Francisco decided to give residents and private actors free access to its municipal data for the purpose of improving the city. Since then, more than 60 apps have been developed in the fields of health, mobility and biodiversity which make life easier for residents. In Singapore, a smart city if ever there was one, online gas and electricity bills allow the customer to see their usage but also to compare the consumption of their neighborhoods, so they can adapt it as a result.
Rather than control and repression, the sustainable city relies on the education and culture of its residents and future generations.
But remember, the word ecological has a double meaning. A sustainable city is ecological in the scientific sense because it conserves biodiversity and gives priority to the dynamics of ecosystems, the materials it uses, and above all its resilience - in other words, its ability to adapt to future weather conditions. This does not mean it is necessarily “ecological” in the political sense or led by a team from a “green” party.
A sustainable city cannot be built without the sharing, education, and solidarity that form the cornerstone of its values. Equal opportunities, gender equality, the inclusion of people with disabilities and equality between generations are central to the sustainable city.
* Philippe Outrequin is the author of L'urbanisme durable. Concevoir un éco-quartier (published by Le Moniteur, May 2011) and Nouvelles architectures écologiques (published by Le Moniteur, May 2016)
** in The Urban Challenge. Reviving the desire to live in a city by Pierre-André de Chalendar (published by Odile Jacob, May 2021)
*** in “Manifesto for circular urban planning” by Sylvain Grisot (published by Dixit.net, February 2020)
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