FutREuse: Understanding Urban Stocks

The Urban Metabolism1 to meet the current and future challenges of cities
The human population is growing fast, and with more than half living in urban areas. This growth is expected to continue in the coming years, with an estimated 60% of the world population expected to be living in cities by 2030 [1]. Cities have always relied heavily on the surrounding countryside to supply resources that cannot be produced directly in the city (i.e. energy, food, water, materials, etc.). Urban discharges (waste, sewage, pollution, etc.) are also often returned to these territories for treatment. Demographic growth and densification in urban areas have thus driven the intensification of both the import of goods and energy as well as the export of waste, increasing the pressure on the environment (natural resources extraction, waste production) and the distances to be covered. These observations and the awareness of our planet’s limits have led some researchers to draw a comparison between cities and the functioning of living organisms. Although the term ‘metabolism’ as applied to societies was formulated in social science works (such as Marx) as early as the nineteenth century, its concrete application as a quantitative study of the city and its relationship with the environment is more recent. The term ‘metabolism of cities’ was coined in 1965 by Abel Wolman, an American engineer. In 1977, a Belgian botanist, Paul Duvigneaud, proposed one of the first ‘urban ecosystem’ studies on Brussels city. Until then, the environmental study of urban environments had been relatively compartmentalised, and offered little overview of pollution and the extractions of resources associated with cities.