Section: Application Domains

Ecological accounting and material flow analysis

One of the major issues in the assessment of the long-term sustainability of urban areas is related to the concept of “imported sustainability”. Indeed, any city brings from the outside most of its material and energy resources, and rejects to the outside the waste produced by its activity. The modern era has seen a dramatic increase in both volume and variety of these material flows and consumption as well as in distance of origin and destination of these flows, usually accompanied by a spectacular increase in the associated environmental impacts. A realistic assessment of the sustainability of urban areas requires to quantify both local and distant environmental impacts; greenhouse gas emissions are only one aspect of this question.

In order to produce such an assessment for a given territory or urban area, one must first establish different types of ecological accounting: one must identify and quantify the different types of material and energy uses on the one hand, and the different types of impact associated to these uses. Two approaches are being investigated. The bottom-up approach relies on Material Flow Analysis (MFA) and Life Cycle Assessment (LCA). One of the major challenges here is to obtain reliable MFA data at the region and département scales, either directly, or through appropriate disaggregation techniques. The top-down approach is based on Environmentally-Extended Input-Ouput Analysis (EE-IOA). This technique which originated from economic sciences has been widely used in recent years in the fiels of ecological economics and industrial ecology. In both cases, the methods aim at tracking environmental flows from the producer to the consumer making them relevant tools for decision-making regarding local modes of production and consumption.

STEEP has started a research program on this theme with three major aims in mind: 1) Creating a comprehensive database enabling such analyses; 2) Developing methodology and models resolving scaling issues, and developing algorithms allowing to rigorously and automatically obtain the adequate assessments; 3) Providing a synthetic analysis of environmental impacts associated to the major material flows, at various geographic levels (employment catchment area, département and région, for France). This research is currently done within an industrial grant with ARTELIA.