Tracing waste, material and carbon flows using input-output models

Abstract

Environmental impacts can be linked to the consumption of goods and services. Determining the extent and location of these environmental impacts can be challenging however, because of the size and complexity of the global economy. Input-output analysis provides a framework in which these supply chains may be unravelled and impacts allocated against the consumption of goods and services. Performing such analysis requires detailed input-output tables, which can be difficult to construct. The Industrial Ecology Virtual Laboratory is an online platform that makes building large scale input-output models easier through a combination of flexibility, automation and collaboration. The laboratory was employed to construct a multi-regional waste input-output table for Australia and to calculate regional waste footprints. These waste footprints were calculated using a number of published waste datasets for consumers in sub-national regions of Australia. Previous to this research, only production-based per-capita estimates of waste generation were available. Research into waste flows in Australia is hindered by a range of data issues, for example no information on the final fate of recycled materials. These issues are addressed through the construction of a time-series of physical input-output tables for Australia. These physical tables were used to estimate the flow of secondary materials back into new production, as well as additions to building stocks over time. Assessments of environmental impacts caused by sub-national regions and cities are of increasing interest. In this research, city carbon footprints are calculated at varying levels of model aggregation and data completeness to demonstrate the effect on footprint results. It is shown that city carbon footprint analyses must include input-output databases and associated calculus in order to avoid severe errors that arise from unacceptable scope limitations caused by the truncation of the footprint assessment boundary.