#35 - 3 July 2020

Zero net artificialization: good intentions, wrong methodology?

We have included the principle of zero net artificialization in the biodiversity plan. What you are now proposing goes further and stronger. So let's go for it! You suggest avoiding new construction that bites into nature when rehabilitation is possible, so let's take a stance! Let's go! You advocate for a moratorium on new commercial zones on the outskirts of cities, let's go! Let's go, let's take action!”. The speaker delivering this inflamed speech is none other than Emmanuel Macron, speaking to the members of the Citizens' Climate Convention on Monday. The "zero net artificialization" objective (ZNA), i.e. the aim to suspend any net increase in the total amount of artificial surfaces, seems praiseworthy: at a time of ecological emergency, protecting biodiversity and natural soils is necessary. But what about the method? "Zero net artificialization" has several hidden flaws.

First of all, no one knows very precisely what artificialization is, or how to measure it. The government's definition of artificialization includes any agricultural, forested, or natural soils the use of which has been modified, which means that parks and gardens are considered artificial, regardless of the ecological services they might provide. With this definition, a garden is considered no better than a parking lot, both being equally artificial! The measurement of artificialization also leaves to be desired: the evaluations carried out use widely different methodologies, allowing them to conclude, for some, that French soils are 9.3% artificialized, and for others, only 5.6%.

Second pitfall: there is a fundamental misunderstanding of artificialization, too often equated with urban sprawl and the image of an "ugly France" devoured by commercial areas. Reality is more nuanced: artificialization concerns both densely populated urban areas and rural territories. Nor is it the systematic consequence of vigorous demographic and economic growth, as it affects territories that are in demographic and economic decline. In Corrèze, for example, the rate of artificialization increased by 13% between 2006 and 2015, even as population grew by only 0.4%.

Third point: the ZNA policy suffers, fundamentally, from insufficient consideration of complexity. Thus, ZNA does not signal the end of soil artificialization, but rather enshrines the need to "renature" artificial surfaces as more are artificialized. While the idea may seem virtuous on paper, it does not stand the test of reality: soils and their characteristics are not identical or even similar and are therefore not interchangeable at will. ZNA also obscures the fact that not all artificialization is necessarily bad. Artificialized soils are mainly used for housing: half of the artificial surfaces between 2006 and 2014 were artificialized for housing, according to INRA and IFSTTAR.

Perhaps the debate on artificialization should be one about fragmentation instead. The latter threatens territorial equilibrium much more than the former, as sociologist and urban planner Éric Charmes pointed out as early as 2013. "It is not so much the disappearance of agricultural land, which is relatively limited anyway, that poses a problem as the nature and location of the artificial land and in particular the urban sprawl of rural areas […] The agricultural world is wrong to demand a halt to artificialization," he concluded at the time. "It would be wiser to call for better organization of urban extensions and better planning. Charmes warns against the pitfalls of "land Malthusianism ", "a source of functional urban sprawl and a contributor to the housing crisis". - Marie Baléo, Head of Studies and Publications


No time to read? La Fabrique de la Cité has got you covered.

WHEN GREY TURNS GREEN (AND GREEN TURNS GREY) – Pandemic, teleworking: the French want to live in green places. Individual homes with gardens and small/medium-sized cities poll well and metropolises cast green votes. Yet, ecologically and economically, it is in the grey concrete heart of metropolises that the grass is greener, as Jean-Marc Vittori reminds us. – Cécile Maisonneuve, President

– The expansion of e-commerce has dealt brick-and-mortar retail a hard blow: more than half the department stores in malls could close by 2021. What will become of these vacant spaces? The Lynnwood project, located north of Seattle, is a laboratory of "large-scale suburban mall-to-housing conversion": by 2022, this former mall will be turned into 300 apartments and some retail spaces for low to middle-income households living in the neighborhood. – Sarah Cosatto, Research Officer

“ALL MODELS ARE WRONG” – “…but some are useful”, said statistician George Box. Although “nothing could have prepared us for what happened as a result of the pandemic”, modelling can help us make more informed decisions. That is the purpose of Pr. Michael Batty’s project, which models the impact of social distancing on land use at the small scale (supermarket), the large scale (land use in general) and in the long term (public transportation). – Chloë Voisin-Bormuth, Director of Studies and Research

NO FLYING CARS IN 2050? – As part of a global reflection on the world of 2050, Politico offers a glance at the future of the European city. Do not expect flying cars or any type of technological fantasy here, but perspectives on the evolution of the city-making philosophy. Beyond the vision of a carless city, metropolises may change metrics to encourage walking, solidarity and inclusion. – Romain Morin, Research Assistant

SPICK AND SPAN, LOUD AND CLEAR – While the overall drop in public transportation ridership (partly for fear of contagion) calls into question its economic sustainability, Parisian networks are presented as a model for resuming public transport operations during a pandemic: daily disinfection of carriages, provision of masks and hand sanitizer, clear communication on social distancing, etc. According to an article published in CityMetric, these elements contribute to users’ trust in mass transit. – Sarah Cosatto

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