The Impacts of Urban Structure and the Related Consumption Patterns on the Carbon Emissions of an Average Consumer

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Abstract

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.

Papers of the dissertation

• Paper I: Heinonen, Jukka; Junnila, Seppo; Kuronen, Matti (2010): A Life Cycle Assessment of Carbon Mitigation Possibilities in Metropolitan Areas, SB10 Finland, Sustainable Community - BuildingSMART, Espoo, 22.-24.9.2010, Finnish Association of Civil Engineers RIL, Conference Proceedings.
• Paper II: Heinonen, Jukka; Junnila, Seppo (2011): Case study on the carbon consumption of two metropolitan cities, International Journal of Life Cycle Assessment, 16, 569-579.
• Paper III: Heinonen, Jukka; Junnila, Seppo (2011): Implications of urban structure on carbon consumption in metropolitan areas, Environmental Research Letters, 6, 014018.
• Paper IV: Heinonen Jukka; Junnila Seppo (2011): Carbon Consumption Comparison of Rural and Urban Lifestyles, Sustainability, 3 (8), 1234-1249.
• Paper V: Heinonen, Jukka; Kyrö, Riikka; Junnila, Seppo (2011): Dense downtown living more carbon intense due to higher consumption: a case study of Helsinki, Environmental Research Letters, 6, 034034.

The author’s contribution in the papers

• Paper I: The author is responsible for writing the paper.
• Paper II: The author is responsible for writing the paper.
• Paper III: The author is responsible for writing the paper.
• Paper IV: The author is responsible for writing the paper.
• Paper V: The author is responsible for initiating the paper, conducting

the assessments and writing the first manuscript of the paper as well as several parts of the final paper.

Introduction

Climate change, in the form of global warming, has been a hot topic throughout the present millennium. Despite some counterarguments [e.g. 1, 2], the phenomenon has been widely accepted [3, 4] and it is often stated as the most severe global environmental problem of our age. Embracing this paradigm set the course for this dissertation.

The overall leading purpose of the dissertation is to analyze the climate change implications of different types of communities living in different types of urban structures. In other words, the aim is to integrate inhabitants into the analysis of the emissions of buildings and urban structures, with the idea that buildings are necessary goods for living, and the building, the urban structure and the location may all affect the lifestyle of the inhabitant. Based on these factors, the dissertation aims to account for all the emissions from consumption, including the upstream emissions of production and supply chains.

The need for this type of consumption-based greenhouse gas (GHG) assessment approach, accounting for all life cycle emissions from consumption, has been recently expressed by several authors [5, 6, 7, 8]. While some such approaches have also been reported in academic journals in the past years [5, 8, 9], space for new contributions is still ample. Within the field, this dissertation contributes especially to the area of city and subcity level GHG assessments, where the academic research tradition is thin [10]. However, the topic is important, as both cities and urban areas appear to be accountable for the majority of all GHG emissions in developed countries [8, 11] and are important contributors in reaching carbon mitigation targets if willing to reduce their emissions [10-12].

While a variety of different calculation tools have been developed by academics and consultants, especially the techniques for a consistent consumption-based GHG assessment on a city or sub-city level are still insufficient. Cities worldwide are setting ambitious GHG reduction targets, but the ways to attain these, and even to assess whether they are reached or not, are still under development. Cities and urban areas in developed countries are demand and consumption centers [5, 8, 13] where the majority of all consumed goods are imported from outside of the geographical city area. Thus, the traditional geographically restricted assessment methods cannot produce sufficient information for effective carbon management, mainly because the results depend heavily on the presence or absence of heavy industries [37]. For example, the carbon footprint of an average resident of Helsinki, the capital of Finland as well as one of the case cities of this dissertation, has been reported in different publications to vary from roughly four tons of GHGs to almost 13. The minimum is reached with assessments limited in scope in both a geographic and a life cycle perspective [14], whereas the consumption-based approach of the dissertation, aiming to account for all life cycle emissions related to all consumption of goods and services of an average resident of the city, results in the highest figure. Neither of these can be claimed to be false as such, but the approach based on limited scopes can hardly be argued to produce sufficient data for efficient city-level management of the global phenomenon of climate change.

The dissertation consists of altogether five individual but interrelated studies reported in four academic journal papers in 2011 and one conference proceeding in 2010. The studies analyze the consumption-based carbon emissions of the inhabitants in different types of urban structures in the Finnish geographical context, examining the impact of the structure and the consumption volume of the emissions. Thus, while the work with the assessment techniques contributes to the field of city-level consumptionbased GHG assessments, the key argument of the dissertation arises from the findings of the five studies. This argument, explained and discussed in detail throughout 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. The key factors lie elsewhere. 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. 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 sufficient indicators. However, the research also indicated means to break the connection between consumption volume and carbon consumption, as will be discussed later.

The result contradicts with some earlier findings [15, 16], but the reasons for the contradiction have been found and reported in some earlier studies as well. For example, Sovacool and Brown (2010) find that the carbon footprints of city residents are substantially higher than country averages in many developing countries, whereas in the developed countries the situation is reversed in general [10]. They state the significantly higher level of the standard of living in the urban areas in the developing countries as one of the key reasons for the result. According to this dissertation, the same argument may also apply in the context of a developed country when the consumption of all the goods and services and their life cycle emissions, which were excluded from the inventory of Sovacool and Brown, are included. City residents outsource a significant amount of their emissions, especially in the developed countries where the heavy industry is often located outside of the cities and even the countries, and imports form a significant share of the overall supply. Thus, their per capita emissions may well be substantially higher than those of the surrounding areas when comprehensive consumption-based analyses are conducted. The results reported by Ramaswami et al. (2008) and Schulz (2007 & 2009) on cities importing a significant share of the goods consumed, and thus GHGs as well, also support the finding of city residents outsourcing their emissions [5, 8, 13]. Evidence for the outsourcing of the emissions taking place on an economy level has also been presented by Wagner (2010), who argues that the energy embedded in the imports of the developed countries may cause their per capita emissions to actually increase even when national inventories would seem to show decreasing patterns [17].

As said above, the argument of the dissertation results from altogether five studies. In the studies, a comprehensive consumption-based assessment model is developed for carbon consumption assessments in different types of areas. The papers present together a coherent set of multiple case studies, all producing similar outcomes. The overall key argument was initially reported already in Paper I of the dissertation. The latter studies, published in Papers II-V, all support the initial finding. In the five papers, the carbon effects of urban structure and consumption volume are analyzed in different types of urban structures and on different levels of urbanization: on the city level with multiple cases of different types of cities (Papers I and II), on the level of metropolitan areas with two distinct metropolitan centers including several cities (Paper III), on a national level based on four types of urban structures (Paper IV), and finally on a sub-city level (Paper V).

The remainder of the dissertation is structured as follows. Section 2 presents the research problem and the context in which the problem is analyzed. Section 3 concentrates on the methodology, presenting first the methods employed in the different papers of the dissertation, and then the wider methodological context of the whole dissertation. In Section 4 the contributions of individual papers are summarized and linked to the research problem as well as to the overall argument of the dissertation. Section 5 summarizes the results and the contribution of the dissertation is put together. Section 5 also evaluates the validity and reliability of the research and assesses needs for future development around the topics of the dissertation. Papers I-V follow the references in Section 6.

Terminology

The dissertation aims at consistent and generally accepted use of terms. However, some terminology is employed in multiple meanings and some may be specific to the research. Short explanations are given below to clarify these.

Research

In the dissertation, the term “the research” refers to the entirety of the dissertation as a whole.

Study/studies

The dissertation consists of multiple interconnected but individual studies. The terms “the study” or “the studies” refer to the individual studies reported in the published papers of the dissertation.

Carbon emissions

In the dissertation, including the individual publications, the term “carbon emissions” refers to all the included GHGs (CO2, CH4, N2O and HFC/PFCs) in carbon dioxide equivalents (CO2e).

Carbon consumption

The term “carbon consumption” is employed to indicate the GHGs released as a result of consumption, when a consumer responsibility perspective is utilized, that is, allocating to a consumer the life cycle emissions (including production and delivery chains) of all his/her consumption.