A two-stage clustering approach to investigate lifestyle carbon footprints in two Australian cities

Andreas Froemelt,Thomas Wiedmann

doi:10.1088/1748-9326/abb502

Abstract

Given the key role of households in driving global emissions and resource use, a change in their consumption behaviours towards more sustainable levels is essential to reduce worldwide adverse environmental impacts. Thereby, focusing on cities is especially important because of today’s large share of the global population living in cities and because local authorities are close to the needs of their residents. However, devising targeted and effective policy measures implies a thorough understanding of prevailing consumption patterns and associated environmental consequences. The goal of this article is to investigate and compare household behaviours and lifestyle-induced carbon footprints in Sydney and Melbourne in order to enhance today’s understanding of household consumption in cities of a high-income, high-emission country. For this purpose, we employed a two-stage clustering approach with a Self-Organising Map and a subsequent Ward-clustering. This allowed for including expenditure data along with socio-economic attributes and thus for recognising lifestyle-archetypes. These emerging archetypes represent households with similar characteristics and comparable consumption patterns. Analysing the archetypes in detail and performing a city-comparison based on multi-dimensional scaling revealed similarities and dissimilarities between the two metropoles. ‘Older’ archetypes seem to behave more alike across cities but show different carbon footprints emphasising the importance of regionalised environmental assessments and of city-specific supply chains. Distinct patterns especially emerged in the high- and low-income segments highlighting the different importance of different lifestyles in each city. Socio-economically similar family-archetypes were found in both cities, but some of them showed diverging consumption behaviours. This article showed that studying household-induced environmental impacts in cities should not rely on macro-trends but should rather be based on city-specific analyses that capture local peculiarities and consider socio-economic characteristics and consumption data simultaneously.

Highlights

Given the fact that more than half of the World’s population lives in urban areas and facing ongoing rapid global urbanisation [1], cities have been identified as key actors to curb adverse environmental impacts (e.g. [2, 3, 4–11, 12–14])
By way of analysing two cities simultaneously, we aim at providing answers to important questions that might further our understanding of household consumption; e.g. Do similar household segments behave across the cities or do we find cityspecific behaviour? These questions are interesting in the context of Melbourne and Sydney since both cities show—except for being located in somewhat different climate zones—many similarities at first glance: same nation, similar population size, high economic importance within the country [5], and both rank among the top most liveable cities in the world [54–56]
In Sydney, the verylow-income segment is subdivided into more archetypes suggesting that the behaviours in this income group might be more distinct than in Melbourne

Summary

Introduction

Given the fact that more than half of the World’s population lives in urban areas and facing ongoing rapid global urbanisation [1], cities have been identified as key actors to curb adverse environmental impacts (e.g. [2, 3, 4–11, 12–14]). Current address: Ecological Systems Design, Institute of Environmental Engineering, ETH Zurich, Switzerland boundaries, but they are especially qualified to abate negative consequences of household consumption behaviours [2, 9–13, 15–18]. [2, 9, 10, 12, 17, 20–24, 25–29]) emphasises the inevitability of changing lifestyles towards more sustainable consumption patterns in order to keep anthropogenic impacts within the carrying capacity of the Earth [30]. This will mitigate risks for humans and environment and help to achieve political targets such as the. The development of such targeted measures that are tailored to the actual city inhabitants require a deep understanding of the variability and peculiarities of local consumption patterns [2, 5, 6–10, 13, 18, 20, 27, 36–38]

Objectives

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Conclusion