The Weight of Cities: A Case Study of the Region of Waterloo

Abstract

The global population is growing at a fast rate, which is resulting in the growth of urban areas worldwide. With the additional 2.1 billion people living in cities by 2050, the urban population will reach 6.5 billion by this year. As a result of this growth and change in society’s affluence, global material consumption will increase from 50 billion tonnes in 2015 to 90 billion tonnes in 2050. Construction materials are one of the major contributors to material consumption in cities. These materials are continuously used to build city stocks, such as buildings and infrastructure to provide services for the growing urban population. Accounting for the current and future material stocks helps policy makers to have an understanding of the quantity of materials that is embedded in cities and how much is required to provide for the future demand. This thesis investigates the quantity of construction materials in residential, non-residential building, road, and sidewalk stocks from 2003 to 2018 in the cities of Kitchener and Waterloo, located in the fastest growing urban area in Canada. The methodology used for this research is in two parts: a bottom-up retrospective approach to account for the quantity of materials from 2003 to 2018, and a mix of demand-driven and bottom-up approaches in the same group of stocks to project the required materials by 2041. The results of this study indicate that the quantity of construction materials in Kitchener and Waterloo has grown from 53Mt in 2003 to 65Mt in 2018, with 24Mt in Waterloo and 41Mt in Kitchener. Material use is estimated to be 160t/capita in Waterloo and a 171t/capita in Kitchener in the year 2018. Based on the growth of population in these cities it is estimated that by 2041 an additional 12Mt of materials will be added to Kitchener and Waterloo’s building and road stocks. This research provides insight for decision makers at the city level to implement more sustainable resource and waste management strategies in the buildings and construction sector.