Viveka Palm

Materials Flow Accounting in Sweden Material Use for National Consumption and for Export

Summary This article presents Swedish economy-wide material flow accounts for the period 1987-1998. It also shows possibilities for enhancing the international comparability of aggregated data on material use, by distinguishing between materials used for consumption and export purposes. The direct material input (DMI) is used as an aggregate measure to estimate the amounts of natural resources (except water and air) that are taken from nature into the economy within a year, including imports to and production within the region in question. The division of materials used for consumption and export purposes avoids double counting trade flows when DMI is applied to a group of countries. The annual DMI in Sweden for 1997-1998, including production and imports, amounts to 24 to 27 metric tons per capita (t/c). The fossil fuel input varies only slightly over the period, from 3.2 t/c in 1991 to 3.6 t/c in 1996, a level deemed unsustainable by the Swedish Environmental Protection Agency. The input of renewable raw materials varies between 8 and 9 t/c. Ores and minerals vary between 11 and 15 t/c. The DMI puts Sweden above estimates made for Germany, the United States, and Japan and in the same range as the Netherlands. The differences in these values can mainly be explained by the relative importance of exports as compared to the size of the economy and by the variation in system boundaries for the data on natural resources. The system boundaries and data sources for natural resources need to be further defined to make the measures fully comparable. Around 5 t/c is exported, whereas the rest, around 20 t/c, is national consumption. The aggregate direct material consumption (DMC), which is the DMI minus exports, communicates the magnitude of resource use. Comparisons of the input with solid waste statistics indicate that quantity of waste (excluding mining waste) in Sweden is equal to about 10% relative of the total resource use. Material collected for recycling by the waste management system is equal to about 5% of the amount of virgin resources brought into society each year.

Data cubes and matrix formulae for convenient handling of physical flow data

Data on flows of materials and substances through the economy and the environment are collected by many different organizations and play a key role in the science of industrial ecology. In this thesis, a framework is suggested for structuring and organizing such data. First, the investigation focuses on the quantities of primary interest in material flow studies and how they can be stored and organized in a data warehouse. This process is shown to provide easy access to data, well-structured data management, a basis for knowledge discovery, and effective analysis of collected data. Secondly, a theoretical framework is proposed for handling and structuring multidimensional flow data, and for facilitating mathematics-assisted modeling in industrial ecology. In particular, it is shown how mathematical operations can be used to merge and compare flow data originating from different studies. Finally, it is illustrated how bootstrap analysis, Bayesian models and balancing procedures can be employed to systematize the quality and uncertainty assessment of physical flow data. Together, these three different aspects of handling physical flow data constitute a new framework that offers better knowledge, quality, and consistency of the data used in industrial ecology.