The impacts of urban structure and the related consumption patterns on the carbon emissions of an average consumer

Climate change, in the form of global warming, has been a hot topic throughout the present millennium, and is currently becoming a more and more widely accepted phenomenon. Urban areas hold a central position in the search for feasible climate change mitigation opportunities as a significant share of all the global greenhouse gas (GHG) emissions is closely related to urban structures. Embracing the situation, cities worldwide are setting ambitious GHG reduction targets. However, the strategies to attain these are still evolving. One explanation is that the cities and urban areas in developed countries are demand and consumption centers where the majority of all consumed goods are imported from outside of the city boundaries. Thus, the traditional geographically restricted assessment methods cannot produce sufficient information for effective carbon management. The dissertation argues that in order to create city level carbon mitigation strategies, which would materialize the potential related to urban areas, it is necessary to identify and understand the emissions caused by the consumers. Derived from this, the dissertation strived to account for all the carbon emissions caused by the inhabitants in different types of urban structures, i.e. their carbon consumption, including the upstream emissions of production and supply chains. To create a clear understanding of the issue, a multiple case study approach was chosen in the Finnish context with each of the individual studies reported in academic journals or conference publications.The studies employ a method based on hybrid life cycle assessment, along with an assessment model developed to calculate city and sub-city level carbon consumption. The main argument of the dissertation is that in the context of the study, the urban structure of an area per se seems to have little effect on the carbon emissions of an average consumer of the area. Rather, the overall consumption volume seems to affect the carbon consumption so strongly that a higher consumption volume indicates higher carbon consumption regardless of the type of the urban structure. The urban structure has a direct impact only on the emissions related to private driving, whereas the emissions from other consumption activities closely follow the overall consumption. Thus, while the environmental, social and functional importance of high urban density and the building type have been demonstrated in a number of studies, from the climate change perspective these factors are not decisive and they are not sufficient measures for effective city level carbon management.