For half a century, the land surrounding our towns has been eaten away at an astounding rate: 20,000 to 30,000 hectares are artificialized each year, or the equivalent of four to five football stadiums…per hour! A progression four times faster than that of the population. At the origin of this very French phenomenon, the dream sold on glossy paper to millions of households to own, one day, a detached house with a garden in a suburban area, stretching the distances between living space, shops, leisure and work. , and making the use of a car essential.
The disappearance of habitats is accelerating the loss of biodiversity
In 2020, the Citizens’ Convention for the Climate defined the artificialization of soils as “any action which consists in transforming open land (natural spaces, gardens and public parks, agricultural plots, forests, etc.) into building land, infrastructure (roads, structures, car parks, etc.) or in artificial spaces (sports fields, paths and construction sites, artificial green spaces)”.
This transformation has, over time, serious environmental consequences: first, the disappearance of habitats accelerates the impoverishment of biodiversity; sealed soils also impede water circulation and carbon storage, cascadingly increasing the risk of flooding and worsening climate change. Then, the reduction of agricultural land also limits production capacities while episodes of droughts and water shortages increase, which threatens the country’s food security. Finally, development and maintenance efforts (roads, electricity, sanitation) are costly and add to the list of nuisances for fauna and flora (pollution, light, noise).
The public authorities were slow to become aware of the phenomenon. In 2018, the government of Edouard Philippe launched the “zero net artificialisation” (ZAN) objective in its biodiversity plan. An intention now integrated into the Climate and Resilience law for 2050, with the addition of a first stage of reducing the rate of space consumption by half over the next ten years (2021-2031). To achieve such an objective, the State intends to work in close collaboration with local authorities, regions and town halls, in particular within the framework of the ELAN law. On the financial side, funds have been deployed via the France Relance plan, with in particular a cumulative sum of 750 million euros allocated to the conversion of wasteland. Urban recycling and the transformation of obsolete buildings are indeed one of the major levers of action against the artificialization of soils. Badly taken into account, with an underestimated real cost and environmental consequences in series, urban sprawl is far from being controlled.
What types of urban recycling?
The Center for Studies and Expertise on Risks, the Environment, Mobility and Development (Cerema) lists on its “cartofriches” site more than 8,200 wastelands (industrial, commercial, tertiary, housing, etc.)
Retraining: the change of use makes it possible to revalorize well-established urban wastelands, but with obsolete or poorly adapted buildings.
Densification : rehabilitation of a roof to add a floor, restoration of a castle transformed into housing or offices. The redevelopment work allows the space to be multiplied without touching the floor surfaces.
Reconstruction : the pollution or degradation of certain structures sometimes involves the partial destruction of buildings in order to rebuild healthier. Old elements can then be kept and reused (façade, basement, load-bearing walls, etc.).
Renaturation : Old or outlying buildings will have difficulty being recycled. It is therefore better to return the site to nature, after depollution and destruction of the infrastructures.
