Academic journal article Sustainability : Science, Practice, & Policy

Can Sustainability Plans Make Sustainable Cities? the Ecological Footprint Implications of Renewable Energy within Philadelphia's Greenworks Plan

Academic journal article Sustainability : Science, Practice, & Policy

Can Sustainability Plans Make Sustainable Cities? the Ecological Footprint Implications of Renewable Energy within Philadelphia's Greenworks Plan

Article excerpt


Municipal sustainability plans typically include laudable environmental goals, but they rarely explain the connection between these goals and a larger conception of sustainability (Dilworth et al. 2011). In this article, we introduce a relatively simple measurement--an ecological footprint (EF) measured per city rather than per capita--that could be used to gauge the extent to which sustainability plans would reduce local consumption of resources from outside the cities' limits. A city that consumes energy produced within its borders to a greater extent than previously would be more sustainable in the sense that 1) it is more self-sustaining and 2) it is less of a resource burden on the larger society. We illustrate our measurement by applying it to one target in the Philadelphia sustainability plan Greenworks, to increase the proportion of electricity used in the city coming from renewable sources to 20%.

EFs are typically calculated at an individual level, by multiplying the land required to sustain the consumption of one person by the number of people that live in some area of interest, such as a city. Using this system of per capita calculation, Wackernagel & Rees (1996) answer the question, "How large an area of productive land is needed to sustain a defined population indefinitely, wherever on Earth that land is located?" By contrast, city sustainability plans look through the opposite end of the telescope, as it were, to ask how their specific land areas, located in specific places on Earth, can be made more sustainable, no matter how many people live on that land. In this article, we thus examine the alternative energy targets within Greenworks regarding not only the degree to which they might reduce the city's overall energy footprint, in terms of the total land required to produce that energy, but also the extent to which their implementation could shift that energy footprint from outside to inside the city.

Since its introduction by Rees & Wackernagel in the 1990s (see Rees, 1992; Rees & Wackernagel, 1994; Wackernagel & Rees, 1996), EF analysis has become increasingly technically advanced, as our literature review describes below. This article contributes to the conceptual rather than technical advancement of EF analysis by suggesting how it might be applied to city sustainability plans and, in turn, how that application might reformulate the measurement of EFs. As we explain in more detail below, using EF analysis to evaluate a municipal sustainability plan implies that a city becomes more sustainable if it becomes more self-sufficient, and a city becomes more self-sufficient if consumption within the city is sustained to a greater extent by land that is also within the city. By this definition, a shift in consumption that increases the total land used to sustain city needs, but that reduces the amount of land used outside of a city, would make a city more sustainable. Such a scenario indicates one of the potentially perverse and unwanted (and, given typical city land-use patterns and regulations, highly unlikely) outcomes of measuring footprints per city rather than per capita, and one we address to a greater extent in the discussion section below. The point of mentioning it here is simply to illustrate the degree to which an energy footprint measured per city is qualitatively distinct from one measured per capita. And rather than resulting in such unwanted outcomes as actually increasing total resource consumption, we suggest that city-level EF analysis, at least with regard to energy, might encourage creative solutions, such as using individual properties for multiple purposes within city boundaries. The renewable energy subsections of this article include a variety of examples.

City Sustainability Plans and Greenworks

Only a limited number of cities in the United States participated in the earlier Local Agenda 21 initiatives sponsored by the International Council of Local Environmental Initiatives (ICLEI) in the 1990s (Lake, 2000). …

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