Material flow analysis (MFA) is a specific environmental accounting approach for quantifying social metabolism at various geographic and institutional scales. MFA at the national level (denoted as economy-wide MFA – see Figure) is probably most advanced in terms of methodological standardisation and indicator development. Economy-wide MFAs are consistent compilations of the annual overall material throughput of national economies, expressing all flows in tonnes per year. As MFA accounts for materials entering and leaving a system, the ‘mass balance principle’ applies, which states that matter can neither be created nor destroyed. All material inputs into a system over a certain period equal all outputs over the same period plus the stock increases minus the releases from stock. In principle, net stock changes can be positive, indicating net accumulation, or negative, indicating stock depletion. In MFA, the mass balance principle is used to check the consistency of accounts. It also allows for the estimation of net additions to stock.
A flow is a variable that measures a quantity per period, whereas a stock is a variable that measures a quantity at a given point in time. MFA is a pure flow concept. It measures the flows of material inputs, outputs and stock changes within the national economy in metric tonnes per year. This means that in MFA stock changes are accounted for but not the quantity of the socio-economic stock itself. Although MFA is a flow concept, it is still important to define carefully what is regarded as a material stock of a national economy, because additions to stocks and stock depletion are essential parts of the MFA framework.
Fischer-Kowalski , M., Krausmann , F., Giljum , S., Lutter , S., Mayer, A., Bringezu, S., Moriguchi, Y., Schütz, H., Schandl, H., and Weisz, H. (2011) ‘Methodology and indicators of economy wide material flow accounting. State of the art and reliability across sources’, Journal of Industrial Ecology, 15: 855 – 876.
This glossary entry is based on contributions by Willi Haas, Simron Jit Singh and Annabella Musel
EJOLT glossary editors: Hali Healy, Sylvia Lorek and Beatriz Rodríguez-Labajos