Eight energy and material flow characteristics of urban ecosystems (12 page pdf, Xuemei Bai, Ambio, Apr. 22, 2016)
Today we examine a review of current literature about two apparently conflicting urban concepts: one that is concerned with the material energy flows, the other with the ecology of wildlife and plants in a city environment. As cities become more complex and larger these concepts become more important in themselves, as well as between each other with intercity distributions and the regulation of processes across large urban areas and estimating the capacity of a city when to comes to the flow of materials, such as waste Approaching cities in this way also allows for a better defined environmental footprint, as demonstrated in one example in Barcelona, where a park designed for carbon sequestration was found after analysis to be one twelve the size needed to produce the desired absorption of carbon emissions from the city. The concluding words are worth noting: “A better understanding of the interactions between anthropogenic material and energy flows and ecosystem processes can help reduce unintended consequences of narrowly focused policy and management decisions.”
Key Quotes :
« The concept of urban metabolism has been widely used to study energy and material flows into and out of cities… recent urban energy and material flow studies have extended far beyond the original metaphor of cities as organism, and started to reveal important characteristics of urban system features and interactions..
Urban energy and material flow efficiency can be defined as how much social/economic services per unit of resource consumption or waste generation can support. It shows how efficient the urban system is in supporting its function, and is an important system performance indicator.”
“The input part of the urban metabolism includes various tangible materials such as food, water, construction and other materials, products, energy, as well as inflow of energy, capital, information, and people. Such input supports societal activities and drives urban functions within a city; forms urban stocks such as housing, building, infrastructure, and green parks; and produces products and services, as well as managed and unmanaged waste and emissions.”
“The output part consists of industrial products, services, knowledge, and various wastes and emissions. The magnitude, distribution, and internal interactions and feedbacks are regulated by policy, governance, culture, and individual and collective behaviour of the urban system.”
“Understanding biogeochemical budgets of ecosystems, in particular nutrients such as carbon, nitrogen, and phosphorus, has been one of the crucial elements of urban ecology”
“The metabolic budget can be used to assess the total ecological footprints of cities”
“The total budget and pathways of material and energy flows reveal the magnitude of impacts and other important characteristics of urban system, such as the functional role of the city, development stages (i.e., mature or growing city), level of infrastructure and development, income, and other socioeconomic characteristics of the city”
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