Implications of urban structure on carbon consumption in metropolitan areas

Urban structure influences directly or indirectly the majority of all green house gas (GHG) emissions in cities. The prevailing belief is that dense metropolitan areas produce less carbon emissions on a per capita basis than less dense surrounding rural areas. Consequently, density targets have a major role in low-carbon urban developments. However, based on the results of this study, the connection seems unclear or even nonexistent when comprehensive evaluation is made. In this letter, we propose a hybrid life cycle assessment (LCA) method for calculating the consumption-based carbon footprints in metropolitan areas, i.e. carbon consumption, with the emphasis on urban structures. The method is input-output-based hybrid LCA, which operates with the existing data from the region. The study is conducted by performing an analysis of the carbon consumption in two metropolitan areas in Finland, including 11 cities. Both areas consist of a dense city core and a less dense surrounding suburban area. The paper will illustrate that the influence of urban density on carbon emissions is insignificant in the selected metropolitan areas. In addition, the utilized consumption-based method links the climate effects of city-level development to the global production of emissions.