A hybrid material flow analysis for quantifying multilevel anthropogenic resources

This study develops a hybrid material flow analysis (HMFA) method to evaluate the annual additional quantity of material stock, known as net additions to stock (NAS) at both micro- and macro-levels through analyzing the fixed capital formation (FCF) and total supply in input-output tables (IOTs). HMFA turns NAS from a balance indicator in the top-down approach to an indicator with meaningful value in terms of urban ore evaluation. To verify the validity of HMFA, this study compares the developed HMFA with a top-down approach and a bottom-up approach through assessing the NAS of Taiwan and Germany. The quantity of NAS estimated by HMFA is considered as a more conservative upper bound than that by the top-down approach, while underestimation often occurs with a bottom-up approach. HMFA has been proven as an efficient and rational evaluation method which overcomes a key limitation in assessing micro-level material stock by a top-down approach, and solves the data demanding problem of the bottom-up approach for quantifying material stock.