The Amazing Potential of Brownfields
Brownfields are an environmental problem that mainly affects cities, as these types of spaces have lost much of their ecological potential. These brownfields, often the result of a former industrial or commercial use, are abandoned spaces that can represent an opportunity for sustainable urban development.
I. Brownfields and soils artificialization
What is a brownfield ?
A brownfield is land that has been abandoned after having been used for industrial, commercial or residential activities. Such land can be left abandoned for a variety of reasons, such as the relocation of industries, the closure of businesses, or changes in land-use policies. Brownfield sites can present environmental risks due to the potential pollution of soil and groundwater by noxious and toxic substances released during the activity of former structures. However, they also offer opportunities for urban redevelopment and the creation of green spaces in cities to improve the resilience of our cities.
Brownfields, a solution against soil artificialization?
The artificialization of soils, which refers to the transformation of natural or agricultural spaces into built environments, has significant social, economic, and environmental impacts. According to the AR6 IPCC reports, soils artificialization leads to diverse issues and exacerbate climate risks :
Economically, even if it creates short-term benefits by creating new infrastructures and increases property values, it results in long-term costs including the loss of productive agricultural lands, which can affect food security. Also, those costs include the management of the environmental impacts of the artificialization on itself.
Environmentally, it can lead to a loss of biodiversity and so the ecosystemic services as it destroys natural lands to make way to built environments. Artificialization of the soils leads to a poor permeability of the lands, encouraging water runoff and aggravating the risk of flooding, which in turn is exacerbated by climate change.
Socially, the IPCC highlights that it can increase poverty and social inequalities, as soils artificialization leads to the displacement of local communities depending on their land for their livelihoods to convert those spaces into urban and industrial use.
Brownfields, due to their previous industrial or commercial use, are often located in urban or peri-urban areas, making them prime locations for redevelopment. This can limit the need for further land artificialization, as it utilizes already disturbed land rather than encroaching on natural or agricultural spaces.
II. Other brownfield’s potential
Brownfield sites offer great potential for the ecological transition.
Rehabilitating brownfields, an ally for Circular Economy
On the one hand, it enables plots of land to be reused by giving them new, appropriate and up-to-date uses; on the other hand, by potentially reusing existing structures and materials, or recycling what can be recycled, it reduces the carbon impact of new constructions. According to the French Urbanist Sylvain Grisot, rehabilitating brownfields is one of the necessary loops in circular urbanism, a vision of urban planning based on the circular economy to create the city of tomorrow. Indeed, it helps to create more frugal cities by limiting the artificialization of land outside cities and recycling vacant spaces.
A solution against land scarcity
As local governments are fighting more and more against soils artificialization, that can lead to threatening developers in the future as it will undeniably lead to a scarcity of land available for new construction. Therefore, brownfields represent an opportunity as they are a great source of land already available and artificialised in our cities.
While the initial investment for brownfield redevelopment can be substantial, it often yields medium to long-term benefits. For instance, it can enhance the attractiveness of a location, recreate city centers, and improve the quality of life. Residents living near a rehabilitated brownfield often see their property values increase. Moreover, it can generate infrastructure savings: in the case of urban expansion, connecting the new district to the city would require creating roads, sidewalks, and drawing electricity and water networks, which would need maintenance for decades. For users and residents, the cost of travel would also be minimized.
The benefits of redevelopment are not only measured in economic terms. Preserving an agricultural surface maintains carbon in the soils and the ability to store it in the long term. Recreating natural spaces in the city can restore soil ecological functions or reconstitute ecological corridors. Avoiding car travel reduces greenhouse gas emissions and thus mitigates climate change. Not to mention the health benefits of having green spaces in the city center. In the case of the Sevran brownfield, France, the improvement in air quality, the creation of a cool island, and the preservation of biodiversity have been noticed, enhancing the health and the quality of life of the residents.
Restoring the ecological potential of cities and improving their resilience
When rehabilitated, brownfield sites can be both depolluted and desartificialized. This makes it possible to reintroduce numerous ecosystem services essential to the city, thanks to the potential renaturation of soils. For instance, if those soils are even partially restored, then their permeability is enhanced: the risk of flood, increased by global warming and highly present in South East Asia, is reduced. The same applies for urban heat islands, reduced by the evapotranspiration phenomenon and the shade caused by the new vegetation onsite. Thus, the restoration of brownfields can lead to an adaptation of the city facing the ineluctable effect of global warming and improving their global resilience.
In conclusion, a brownfield is at first glance obsolete, but it offers enormous potential. Rehabilitating them is part of a logic of land sobriety, limiting soils artificialization and reintroducing environmental, social and economic benefits to our cities.
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