The Carbon Footprint of our Urban Areas

This is my first blog post and I want to take this opportunity to reflect on how the scholarly literature on urban sustainability, as well as planning and policy practice, has mostly dealt with cities as geographically bounded spaces. This perspective shapes how we think sustainability as it relates to cities (as well as strategies to foster sustainable transitions).  Research in this domain, for example, has emphasized how buildings, land use patterns, and transportation systems affect the sustainability of cities. These are clearly important foci. However, consumer products and their consumption are largely ignored in urban sustainability discourse and practice, despite the enormous volume of materials and embodied energy used in their manufacture, distribution, and disposal, and the geographically variable impacts of their supply chains.

Emerging research, however, points to the enormous environmental and social implications of consumption by urban dwellers.  In an interesting paper (“Implications of urban structure on carbon consumption in metropolitan areas”) recently published in the journal, Environment Research Letters, two scholars from Finland (Jukka Heinonen and Seppo Junnila) concluded that urban density played a relatively insignificant role in the carbon footprint of the two metropolitan areas that they studied. This finding runs counter to the prevailing belief that dense metropolitan areas have lower per capita carbon emissions than the lower density surrounding areas. They came to this conclusion using a hybrid input-output Life Cycle Assessment method to calculate a consumption-based carbon footprint of the two metropolitan areas. The two authors argue that income level can better explain the reason for the variation and they point to the large embodied energy in consumer products in the overall footprint.

While I take issue with some of the methodological approaches used to calculate the consumption-based urban footprints in this study, I foresee a slew of articles on the crucial role of consumer products in the overall carbon footprint of our urban areas. Recently, I reviewed a manuscript for the same journal that quantified the carbon footprint of the urban metabolism for multiple cities and it also points to the large role of product consumption by urban dwellers.

Stay tuned!