The Materials Book

199 cities use billions of tons of raw materials, from fossil fuels, sand, gravel, and iron ore to biotic resources such as wood and food. The high demand for such raw materials far exceeds what the planet can provide. Resources should now become a central policy concern. Furthermore, the long-term historic de-densification trend of 2 percent per year (i.e., that cities are becoming less compact) threatens to increase global urban land use from just below one million km² to over 2.5 million km² by 2050, putting agricultural land and food supplies at risk. The Weight of Cities report proposes three major interventions to halve urban resource requirements by 2050: 1. Introduction on a mass scale of resource-efficient urban infrastructure (specifically, bus rapid transit instead of passenger cars, green commercial buildings instead of conventional office blocks, and district energy instead of boilers and air conditioners). This could achieve a 24 to 47 percent reduction in impacts on water, energy, land, and metals by 2050 in comparison with a baseline for these sectors. 2. Reverse the century-long de- densification tendency using various interventions, resulting in a ten-fold reduction in resource consumption. 3. Implement new modes of urban governance that foster accelerated experimentation and innovation across all major urban sectors, with special attention to mobility, housing, food, and energy. Urban dematerialization on this scale will not happen via market mechanisms alone. It will require purposeful interventions by public-sector institutions at different levels in order to ensure that the transitions are just and deep. However, this does not advocate for a return to a Weberian bureaucratic golden age where development is determined exclusively by the state. Instead, public-sector institutions should support the emergence of the urban commons—the shared physical and virtual spaces that conjoin within newly configured urban spaces and allow urban settlements to thrive in an environment of abundance and cultural flowering. Dematerialization, in this context, becomes the organizing framework for new modes of urban living, prosperity, and human flourishing. In order to get a handle on how to address the quantified domestic material consumption of coming urbanization, it is important to recognize that the configuration of urban form and infrastructure, functions, and metabolisms has changed several times and quite radically over the past 150 years. Appreciating this track record makes it easier to understand what may be emerging following the 2007–8 financial