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ANDERSON SERANGOON JUNIOR COLLEGE H1 GEOGRAPHY THEME 2 -URBAN CHANGE TOPIC 2.1 SuSTAINABLE URBAN DEVELOPMENT lo5 MANAGEMENT OF TRAFFIC CONGESTION 1. 2 big picture'quantification of the productive processes within Overview: o city and the consequent inputs and outputs Urban Metabolism Due to CLUSTER 1: SuSTAINABLE FUTURE AND CLIMATE CHANGE TOPIC 1.1 CITIES INA SUSTAINABLE FUTURE Introduction: 03 Demand Placed on Natural Environments Takes the form of: High demand placed on natural environments High concentrations of waste Large ecological footprint Sustainable Urban Development Reflected by: Resources absorbed by Demand placed on natural environments 2.1. High concentration of waste 2.2. Large ecological footprint 4 Conclusion cities from surroundings Updated Mar 2023 1.1. Urban Metabolism and Sustainable Urban Development Circular Urban Metabolism 2.3.2. City demand for water resources Linear Urban Metabolism Leods to: 2.3.1. Extraction of biofuels to meet energy demands of cities 3.1. Waste not viewed as a potential resource 2.3. Vast quantities of resources absorbed by urban areas from the surrounding areas 3. Consequences of the high demand placed on natural environments 3.2. Environmental problems in surrounding areas Leads to: 3.2.1. Example -Consequences of logging 3.2.2. Example-Consequences of extraction of groundwater Hinders Impacts of high demand on natural environments Waste not viewed as potential resource Environmental problems in surrounding areas

ANDERsON SERA NCAAM ANDERSON SERANGOON JUNIOR COLLEGE H1 GEOGRAPHY THEME 2 -URBAN CHANGE TOPIK 2.1 SusTAINABLE URBAN DEVELOPMENT I Os MANAGEMENT OF TRAFFIC CONGESTION Key Question: How does the demand placed on natural environments by urban areas influence progress towards sustainable development? 1. Introduction m Te previous lecture, we discussed urban population trends and how the high urbanisation rates and rapid urban growth pose serious challenges to sustainable urban development. Specifically, high urbanisation rates and urban growth is a key driver of resource consumption and Waste generation, which then leads to environmental issues that become a challenge to sustainable urban development: City-based production currently accounts for the majority of resource consumption and waste generation worldwide. Cities consume more than two-thirds of global energy and produce over 70 percent of carbon emissions (World Bank, 2010). Cities alsO present a number of environmental problems associated with the demands they place on ecosystems, resources and sinks of the surrounding region. In this lecture, we explore how the demands placed on natural environments by urban areas influence progress towards sustainable development. 1.1 Urban Metabolism and Sustainable Urban Development as: The concept of urban metabolism stems from the idea that cities are similar to organisms, as they both consume resources from their surroundings and excrete waste. Hence, the study of a city's urban metabolism involves 'big picture' quantification of the inputs, outputs and storage of energy, water, nutrients, materials and wastes for an urban region. 'Inputs' refer to the resources needed in the city In order to progress towards sustainable development, a better understanding of how natural resource use correlates with urban economic activities is necessary. The concept of urban metabolism is helpful in doing so 'Outputs' refer to the result of consumption of resources -e.g. generation of waste. Assessing the metabolism of urban areas provides important clues about the direct and indirect environmental impacts of consuming natural resources. The framework of urban metabolism can also help identify the most effective infrastructure design and technology choices for diverse cities in different development contexts, such as those for waste management, as well as the potential for establishing a "circular economy" (see Box 1). Box 1: Circular Economy A circular economy is a framework of production and consumption that incorporates sharing, leasing, reusing, repairing, refurbishing and recycling of materials and products up to their maximum lifespan: This approach addresses global issues such as pollution, waste, and climate change, by focusing on three basic principles that provides the transformation to a circular economy: eliminating waste and pollution Updated Mar 2023 circulating products and materials, and 2

ANDERSON SERANGOON JUNIOR CoLLEGE H1 GEOGRAPHY THEME 2 -URBAN CHANGE TOPIC 2.1 SUSTAINABLE URBAN DEVELOPMENT os MANAGEMENT OF TRAFFIC CONGESTION the regeneration of nature. A circular economy is often seen as contrasting the traditional linear economy. Urban metabolism therefore provides a framework for analysing the technical and socioeconomic processes tnat ocCur in cities, as if the city were an ecosystem. It can be used to analyse how urban areas function with regard to resource use and the underlving infrastructures, and more broadly, the relationship between human activities and the (natural) environment. IMPORTs (Rest of the countr) IMPORTs (Rest of the orld) LOCAL EXTRACTION ECONOMIC ACTIVITY ECONOMIC ACTIVITY 3 Updated Mar 2023 ECONOMIC ACTIVITY 1 URBAN BOUNDARIES URBAN ECONOMY 4 ECONOMIC ACTIVITY FINAL CONSUMPTION ADDITION TOSTOK NDALLING Fig. 1 Schematic Representation of Urban Metabolism WASTES& EMISSIONS EXPORTS (Rest of the country) Imports to an urban area may come from the rest of the country or from abroad. EXPORTS (Resta Fig. 1 is a schematic representation of urban metabolism, where the material flows of an urban area are illustrated. the Together with locally extracted materials, imports are used by the urban economic activities to produce goods and services that will be consumed within the city by other economic activities and by the citizens, or exported (to the rest of the country and to the rest of the world). A portion of the materials consumned is accumulated in the material stock of the local economy (as buildings, infrastructure, and durable goods). The rest leaves the economy as valuable products, waste, and emissions (to the local environment or beyond). The difference between natural ecosystems and cities is in how inputs and outputs mcve through the system: In natural ecosystems, the output of an organism is frequently also an input that renews and sustains the environment-hence inputs and outputs move in a cyclical fashion. However, inputs and outputs move through a city in a linear fashion (Fig. 2): E.g. Raw materials are extracted, combined and processed into consumer goods, many of which end up as non-biodegradable waste that cannot be absorbed into the natural environment.

ANDERSON SERANGoON JUNIOR CoLEGE H1 GEOGRAPHY THEME 2-URBAN CHANGE TOPIC 2.1 SuSTAINABLE URAAN DEVELoPMENT I os MANAGEMENT OF TRAFFIC cONGESTION E.g. Nutrients are taken from the land when harvested from food. However, these nutrients are not returned as most urban sewage systems discharge into rivers and coastal waters. Food Energy Updated Mar 2023 Goods Water FOoa Ronowablo ener gy Goods water Linear metabosm cities consume and pollute at a nigh rate Inputs Clty Inputs Circuiar metabollsm, ctles minimize nevw inputs and maximlze retyciing Organie waste recyciea CIty Inorganic waste recycled Outputs Outputs Fig. 2 Comparison between linear and circular metabolism Organic waste Emissions Inorganlc waste Waste water 4 Zero emissions As seen from Fig. 2, this impedes progress towards sustainable development because a linear nature of production, consumption and disposal in cities is unsustainable in the long run, with both the use of resources and the amount of generated waste increasing to staggering proportions. It has therefore been argued that cities need to move towards a resource-efficient circular metabolism. The latter differs in that all wastes produced are recycled and reused as inputs for ci