Eight energy and material flow characteristics of urban ecosystems.

Xuemei Bai

doi:10.1007/s13280-016-0785-6

Abstract

Recent decades have seen an expanding literature exploring urban energy and material flows, loosely branded as urban metabolism analysis. However, this has occurred largely in parallel to the mainstream studies of cities as ecosystems. This paper aims to conceptually bridge these two distinctive fields of research, by (a) identifying the common aspects between them; (b) identifying key characteristics of urban ecosystems that can be derived from energy and material flow analysis, namely energy and material budget and pathways; flow intensity; energy and material efficiency; rate of resource depletion, accumulation and transformation; self-sufficiency or external dependency; intra-system heterogeneity; intersystem and temporal variation; and regulating mechanism and governing capacity. I argue that significant ecological insight can be, or has the potential to be, drawn from the rich and rapidly growing empirical findings of urban metabolism studies to understand the behaviour of cities as human-dominated, complex systems. A closer intellectual linkage and cross pollination between urban metabolism and urban ecosystem studies will advance our scientific understanding and better inform urban policy and management practices.

Highlights

The concept of urban metabolism has been widely used to study energy and material flows into and out of cities, with a rapidly growing body of literature over the last 10 years (Decker et al 2000; Warren-Rhodes and Koenig 2001; Kennedy et al 2007; Zhang and Hu 2011)
I present some important characteristics of an urban ecosystem that can be derived from urban metabolism studies, which is categorized into eight aspects
Recent urban metabolism literature shows a large potential: for some resources, over 50 % and up to a 100 % of selfsufficiency is possible by quality differentiation of resources and innovative collaboration between the public and private sectors within the city (Baccini 1997; Beatley 2007; Agudelo-Vera et al 2012)

Summary

Introduction

The concept of urban metabolism has been widely used to study energy and material flows into and out of cities, with a rapidly growing body of literature over the last 10 years (Decker et al 2000; Warren-Rhodes and Koenig 2001; Kennedy et al 2007; Zhang and Hu 2011). It has started as a metaphor of likening cities to a living organism, and while there are precursors of such thinking (FischerKowalski and Huttler 1998), modern use of the concept was pioneered by Abel Wolman in his study of an imaginary city of 1 million people, looking at total resource inputs into the city, and waste output from the city (Wolman 1965). Research has tended to focus predominantly on quantifying various flows in and out of cities, without critical analysis of the concept (Lifset 2004; Swyngedouw 2006), or conscious effort to build upon and extend beyond empiricism—little attention has been paid to understanding how such approach and accumulated empirical evidences can

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Conclusion