A Demand-Centered, Hybrid Life-Cycle Methodology for City-Scale Greenhouse Gas Inventories

Department of Civil Engineering, University of Colorado Denver, Denver, Colorado, USA.
Environmental Science and Technology (Impact Factor: 5.33). 10/2008; 42(17):6455-61. DOI: 10.1021/es702992q
Source: PubMed


Greenhouse gas (GHG) accounting for individual cities is confounded by spatial scale and boundary effects that impact the allocation of regional material and energy flows. This paper develops a demand-centered, hybrid life-cycle-based methodology for conducting city-scale GHG inventories that incorporates (1) spatial allocation of surface and airline travel across colocated cities in larger metropolitan regions, and, (2) life-cycle assessment (LCA) to quantify the embodied energy of key urban materials--food, water, fuel, and concrete. The hybrid methodology enables cities to separately report the GHG impact associated with direct end-use of energy by cities (consistent with EPA and IPCC methods), as well as the impact of extra-boundary activities such as air travel and production of key urban materials (consistent with Scope 3 protocols recommended by the World Resources Institute). Application of this hybrid methodology to Denver, Colorado, yielded a more holistic GHG inventory that approaches a GHG footprint computation, with consistency of inclusions across spatial scale as well as convergence of city-scale per capita GHG emissions (approximately 25 mt CO2e/person/year) with state and national data. The method is shown to have significant policy impacts, and also demonstrates the utility of benchmarks in understanding energy use in various city sectors.

Full-text preview

Available from:
  • Source
    • "Therefore a consumption-based approach to urban environmental sustainability is suggested to add to the possibilities for influencing global issues through local actions (Holden and Norland 2005;Neuman 2005;Eaton et al. 2007;Hoornweg et al. 2011). The logic of a consumption-based evaluation is that urban areas are considered to be responsible for all the direct and indirect environmental impacts of all the products and services the inhabitants consume, regardless of where geographically the environmental impacts take place (Ramaswami et al. 2008;Weber and Matthews 2008;Kennedy et al. 2010). This article discusses the rationale of current urban development policies and practices in their push for the reduction of environmental load as it relates to a consumption-based idea of urban environmental sustainability . "

    Full-text · Article · Dec 2015
  • Source
    • "Greenhouse gas emissions for individual cities more frequently have been estimated rather than observed or measured (Marcotullio et al., 2012). Researchers have developed inventory protocols to help in the estimation process (Ramaswami et al., 2008; Kennedy, 2012; Kennedy et al., 2009a,b). Urban emissions variables, dimensions and indicators in the typology were derived from a review of existing literature and include aspects of how GHGs are estimated in total and per different energy fuel mixes, what category of emissions dominate (i.e. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Urban areas are key sources of greenhouse gas (GHG) emissions and also are vulnerable to climate change. The recent IPCC Fifth Assessment Report illustrates a clear need for more research on urban strategies for climate change adaptation and mitigation. However, missing from the current literature on climate change and urban areas is a conceptual framework that integrates mitigation and adaptation perspectives and strategies. Because cities vary with respect to development histories, economic structure, urban form, institutional and financial capacities among other factors, it is critical to develop a framework that permits cross-city comparisons beyond simple single measures like population size.The primary purpose of this paper is to propose a conceptual framework for a multi-dimensional urbanization climate change typology that considers the underlying and proximate causes of GHG emissions and climate change vulnerabilities. The paper reviews some of the basic steps required to build such a typology and associated challenges that must be overcome via a demonstration of a pilot typology with nine case study cities. The paper shows how the proposed framework can be used to evaluate and compare the conditions of GHG emissions and climate change vulnerability across cities at different phases in the urbanization process.
    Full-text · Article · Nov 2015 · Urban Climate
  • Source
    • "Other organizations have constructed accounting systems to deal with different scales, including the GRIP system for the European Metropolis (Carney et al., 2009), the ICLEI system (mentioned above) for cities, and the World Resources Institute/World Business Council on Sustainable Development system for enterprises (WRI/WBCSD, 2009). Based on the research that led to these systems , Ramaswami et al. (2008) accounted for the carbon emission of Denver at three scales, and distinguished between carbon emission inside and outside of the city's boundary. Although the focus and objectives differed among these organizations, they all provided empirical coefficients that can be used in carbon accounting and that have greatly reduced the difficulty of such accounting. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Global climate change has aroused widespread interest in reducing carbon emissions and increasing carbon sequestration. Thus, an urban carbon inventory must consider both emissions and sequestration. In this context, we analyzed the main contributors to the flows that comprise a city's carbon metabolic processes employing methods and concepts from ecological science. The carbon emissions and sequestration by urban carbon metabolic processes can be compared to ecological catabolism and anabolism, respectively. We used empirical coefficients to estimate the rates of carbon catabolism and anabolism and calculate the resulting carbon imbalance index. Our analysis reveals the contributions of individual metabolic actors and the distribution of the metabolic flows among them. Taking Beijing as a case study, we found that the catabolic rate of the metabolic actors was more than five times the anabolic rate from 1995 to 2010, leading to a carbon imbalance index that was twice the average Chinese level. The major catabolic actors were the other services and domestic sectors. These catabolic rates were primarily influenced by the flows of electricity, heating energy consumption, and mobile energy consumption. The overall carbon imbalance resulted from greatly reduced metabolic flows in farmland anabolism due to conversion of farmland into urban land. Identifying the metabolic actors and flows in this manner will inform government mitigation efforts by identifying where reduction is required and guiding planning of appropriate mitigation actions. Our study also provides directions for conservation of the urban ecological environment.
    Full-text · Article · Nov 2015 · Ecological Modelling
Show more