Methodological and Ideological Options Quantifying the sustainability of economic resource networks: An ecological information-based approach Ali Kharrazi a, ⁎, Elena Rovenskaya b, c , Brian D. Fath b, d , Masaru Yarime f , Steven Kraines e a Graduate Program in Sustainability Science, Graduate School of Frontier Sciences, University of Tokyo, Japan b Advanced Systems Analysis Program, International Institute for Applied Systems Analysis (IIASA), Laxenburg, Austria c Faculty of Computational Mathematics and Cybernetics, Lomonosov Moscow State University (MSU), Moscow, Russia d Biology Department, Towson University, Towson, MD, USA e Future Center Initiative, University of Tokyo, Japan f Graduate School of Public Policy, University of Tokyo, Japan abstract article info Article history: Received 6 January 2013 Received in revised form 19 March 2013 Accepted 22 March 2013 Available online xxxx Keywords: Economic resource networks Ecological information theory Indicators Robustness Sustainability Sustainability as a concept has multiple disparate perspectives stemming from different related disciplines which either maintain ambiguous interpretations or concentrate on metrics pertaining to single aspects of a system. Given the embedded multi-dimensionality of sustainability, systemic approaches are needed that can cope with interactions of different dimensions. Past efforts for measuring sustainability holistically have taken an accounting approach based on the availability and efficiency of resource flows. However, an accounting approach fails to fully incorporate the intensive parameters pertaining to sustainability. An eco- logical information-based approach is a promising holistic measurement which incorporates both intensive and extensive dimensions of sustainability. This paper evaluates this approach by applying it to six economic resource trade flow networks: virtual water, oil, world commodity, OECD + BRIC commodity, OECD + BRIC foreign direct investment, and iron and steel. From the perspective of biomimicry, it appears that these net- works can achieve higher levels of efficiency without weakening their robustness to resource delivery. The trends of measured efficiency and redundancy of the studied networks are demonstrated to be useful in reflecting long term changes while the trend in robustness levels were found to exhibit similar behavior to an ecosystem in its early phase of development. © 2013 Elsevier B.V. All rights reserved. 1. Introduction Sustainability is an increasingly important new paradigm of the modern age upon which to base future policies. However, a universal- ly accepted definition for sustainability has been difficult to achieve as the terminology remains open to different interpretations. Quantifi- cation of sustainability could create a common ground to compare al- ternative policies. However, existing single issue indicators examine only partial dimensions of a system. The challenge lies in the mea- surement of sustainability as a holistic metric at the system level. Previous efforts to quantify sustainability include emergy, exergy, ecological footprint, and information-based approaches. In the first three methods, sustainability is quantified from an accounting perspec- tive where the resource availability, limits to inputs, and consumption efficiencies are emphasized. This perspective is valuable in detecting unsustainable usage of resources based on their availability or ineffi- cient consumption, and it has been extensively applied not only to eco- logical systems, e.g., Odum et al. (2000); Mandal et al. (2012) but also to urban systems, e.g., Jiang et al. (2009); Huang and Chen (2005), regional systems, e.g., Sciubba et al. (2008); Lei et al. (2009), and national sys- tems, e.g., Ertesvag and Mielnik (2000); Gasparatos et al. (2009); Wackernagel et al. (1999); Dai et al. (2012). We see the accounting per- spective, however, to lack insight in two critical aspects towards mea- suring the sustainability of a system. First, we question whether one can equate increased sustainability simply with decreasing the total re- source consumption within a system — either through increasing a system's efficiency or lowering resource demand. Secondly, the ac- counting perspectives do not consider a system's dynamic response to changes such as perturbations, stress, or external shocks. Information- based approaches, on the other hand, examine the configuration of flows within a network of interactions within the system, which can shed light on these dimensions. Researchers in this avenue have evalu- ated the sustainability of the dynamic state of systems using the Fisher information definition (Cabezas and Fath, 2002) and measured growth and developments of systems (Ulanowicz, 2001) using an ecological information-based approach. This paper will consider the second eco- logical information-based approach. Being robust to changes in the flows within a network, resulting for example from stresses such as extinction, drought, climate change, and recession, is considered important for a system to be sustainable Ecological Economics 90 (2013) 177–186 ⁎ Corresponding author. Tel.: +81 471364877. E-mail address: alik@sustainability.k.u-tokyo.ac.jp (A. Kharrazi). 0921-8009/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.ecolecon.2013.03.018 Contents lists available at SciVerse ScienceDirect Ecological Economics journal homepage: www.elsevier.com/locate/ecolecon