Growing concern regarding environmental, social, economic and food quality outcomes of the modern global industrial food system as well as the implications of climate change on food security and food system sustainability have fomented interest in, and action to advance localized food systems. Environmental stewardship is an oft-touted benefit of food system localization. However, few studies have comparatively examined actual environmental benefits of local versus global supply systems and most focus on only one aspect (e.g., GHG emissions). The study reported here comparatively analyzes land, water, carbon and ecological footprints of a localized food supply and contemporary global food supply for the South-West British Columbia (Canada), bioregion (SWBC). The footprint family approach utilized allows measuring overall biophysical loads for the studied region. We quantified regional rates of reliance on imported biophysical services; measured the performances of specific food products grown locally in comparison with their imported counterparts; and identified those commodities that have better and worse local biophysical performances. For the SWBC bioregion, only 35% of the food consumed in the region is locally produced. Supplying the region's food demands requires 2 million hectares of land and 3 billion m3 of water, generating approximately 2.8 million tons of CO2e, with an eco-footprint of 2.5 million gha. Examining a large number of commodities grown and consumed in the bioregion revealed that only some commodities grown locally have absolute or significant biophysical advantages, while the rest have very little to no local advantage. Our analysis challenges the notion that local food systems are necessarily more environmentally sustainable from a biophysical resource use perspective and therefore may not represent the most compelling argument(s) for food system localization. We call for better and more comprehensive comparative analysis of existing and desired food systems as a mean to advance sustainability.

Although many cities are engaged in efforts to calculate and reduce their greenhouse gas (GHG) emissions, most are accounting for "scope one" emissions i.e., GHGs produced within urban boundaries (for example, following the protocol of the International Council for Local Environmental Initiatives). Cities should also account for the emissions associated with goods, services and materials consumed within their boundaries, "scope three" emissions. The emissions related to urban consumption patterns and choices greatly influence overall emissions that can be associated with an urban area. However, data constraints and GHG accounting complexity present challenges. In this paper we propose one approach that cities can take to measure the GHG emissions of their material consumption: the solid waste life cycle assessment (LCA) based approach. We used this approach to identify a set of materials commonly consumed within cities, and reviewed published life cycle assessment data to determine the GHG emissions associated with production of each. Our review reveals that among fourteen commonly consumed materials, textiles and aluminum are associated with the highest GHG emissions per tonne of production. Paper and plastics have relatively lower production emissions, but a potentially higher impact on overall emissions owing to their large proportions, by weight, in the consumption stream.

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