<p>Sharing the information of product environmental performances among multi stakeholders is critically important to promote eco-design by producers and replacement of ordinary products to eco-products in the society. These results of assessment should be based on scientific approach and these results should also be comprehensive to cover the significant environmental impacts as far as possible. The authors developed an environmental hotspot analysis method which integrate the following three methods; an updated Japanese inventory database（IDEAv2）, waste input output analysis（WIO）which includes downstream processes of products and services, and Japanese impact assessment method including weighting among endpoints（LIME2）. We carried out hotspot analysis for 100 products and services in Japan using the method developed in this research project. These calculated results are shared with program holders of TypeI ecolabel and TypeIII ecolabel and these results are expected to increase the reliability of evaluation criteria in these programs.</p>

<p>In recent years, in order to establish a recycling-oriented society, Japan has been working on the improvement of resource recovery rate, on waste reduction and on the increase of the waste treatment energy efficiency under the 4th Fundamental plan for establishing a sound material-cycle society. Therefore, in this research, based on an input-output approach, we tried to calculate the Japanese waste footprint by using the extended waste input-output table. The amount of waste generated and landfilled waste through the life-cycle of each industrial sector were highlighted. Later, the waste footprint was compared with the carbon footprint, it was shown that reducing waste for "food manufacturing", "eating and drinking services" and "building construction" would lead to the mitigation of climate change.</p>

Since its development at the end of the previous century, the waste input–output (WIO) model has been extended to wide areas of industrial ecology including material flow analysis (MFA), life-cycle costing (LCC), regional analysis, and linear programming (LP)-based technology selection. To our knowledge, the dynamics of waste generation and recycling is an area of possible conceptual extension that remains least explored. Building upon our recent work on dynamic MFA, in this work, we develop a dynamic WIO (dWIO) model that fully considers the issue of quality in recycling that involves mixing, dissipation, and contamination.

The prevention and recycling of food waste contribute to a circular economy due to improvements in resource efficiency and energy recovery. This study introduces a framework for evaluating the prevention and utilization of food waste using Japanese food industry data from 2008 to 2015. To elucidate the changes in the amount of unutilized food waste, this study applies a decomposition analysis framework that classifies five factors: waste prevention, food recycling, heat recovery, volume reduction, and production scale. The results show that the amount of unutilized food waste throughout the food industry decreased between 2008 and 2011, primarily due to three factors: increased food waste recycling, volume reduction, and a decrease in production scale. However, the key factors driving changes in food waste management varied by food industrial sectors. The primary drivers of the decline in unutilized food waste were recycling in the food manufacturing industry, waste prevention in the retail industry, and a decrease in production scale in the food service industry. Thus, policies for food waste management should account for the diversity of characteristics across food industries and the food waste management strategies employed.

Importance of end-of-life vehicles (ELVs) as an urban mine is expected to grow, as more people in developing countries are experiencing increased standards of living, while the automobiles are increasingly made using high-quality materials to meet stricter environmental and safety requirements. While most materials in ELVs, particularly steel, have been recycled at high rates, quality issues have not been adequately addressed due to the complex use of automobile materials, leading to considerable losses of valuable alloying elements. This study highlights the maximal potential of quality-oriented recycling of ELV steel, by exploring the utilization methods of scrap, sorted by parts, to produce electric-arc-furnace-based crude alloy steel with minimal losses of alloying elements. Using linear programming on the case of Japanese economy in 2005, we found that adoption of parts-based scrap sorting could result in the recovery of around 94-98% of the alloying elements occurring in parts scrap (manganese, chromium, nickel, and molybdenum), which may replace 10% of the virgin sources in electric arc furnace-based crude alloy steel production.

Alloying metals are indispensable ingredients of high quality alloy steel such as austenitic stainless steel, the cyclical use of which is vital for sustainable resource management. Under the current practice of recycling, however, different metals are likely to be mixed in an uncontrolled manner, resulting in function losses and dissipation of metals with distinctive functions, and in the contamination of recycled Steels. The latter could result in dilution loss, if metal scrap needed dilution with virgin iron to reduce the contamination below critical levels. Management of these losses resulting from mixing in repeated recycling of metals requires tracking of metals over multiple life cycles of products with compositional details. A new model (MaTrace-alloy) was developed that tracks the fate of metals embodied in each of products over multiple life cycles of products, involving accumulation, discard, and recycling, with compositional details at the level of both alloys and products. The model was implemented for the flow of Cr and Ni in the Japanese steel cycle involving 27 steel species and 115 final products. It was found that, under a high level of scrap sorting, greater than 70% of the initial functionality of Cr and Ni could be retained over a period of 100 years, whereas under a poor level of sorting, it could plunge to less than 30%, demonstrating the relevance of waste management technology in circular economy policies.

Substantial amounts of post-consumer scrap are exported to other regions or lost during recovery and remelting, and both export and losses pose a constraint to desires for having regionally closed material cycles. To quantify the challenges and trade-offs associated with closed-loop metal recycling, we looked at the material cycles from the perspective of a single material unit and trace a unit of material through several product life cycles. Focusing on steel, we used current process parameters, loss rates, and trade patterns of the steel cycle to study how steel that was originally contained in high quality applications such as machinery or vehicles with stringent purity requirements gets subsequently distributed across different regions and product groups such as building and construction with less stringent purity requirements. We applied MaTrace Global, a supply-driven multiregional model of steel flows coupled to a dynamic stock model of steel use. We found that, depending on region and product group, up to 95% of the steel consumed today will leave the use phase of that region until 2100, and that up to 50% can get lost in obsolete stocks, landfills, or slag piles until 2100. The high losses resulting from business-as-usual scrap recovery and recycling can be reduced, both by diverting postconsumer scrap into long-lived applications such as buildings and by improving the recovery rates in the waste management and remelting industries. Because the lifetimes of high-quality (cold-rolled) steel applications are shorter and remelting occurs more often than for buildings and infrastructure, we found and quantified a tradeoff between low losses and high-quality applications in the steel cycle. Furthermore, we found that with current trade patterns, reduced overall losses will lead to higher fractions of secondary steel being exported to other regions. Current loss rates, product lifetimes, and trade patterns impede the closure of the steel cycle. (C) 2016 Elsevier B.V. All rights reserved.

This study seeks to understand the role of primary processing, i.e. the first post-mining stage, in supply risk, by means of a case study on three critical metals (neodymium, cobalt, and platinum) in the context of Japan. Applying the footprint' concept with a multiregional input-output model, we have quantified the direct and indirect vulnerability of the Japanese economy to such risks. Considering the supply risks associated with primary processors, we find that Japanese final consumers are exposed to relatively higher supply risks for neodymium as compared with cobalt and platinum. Our study shows that the primary processing stage of a metal's supply chain may contribute significantly to the overall supply risks, suggesting that this stage should be taken into due account in understanding and mitigating supply-chain vulnerability through, e.g. supplier diversification and alternative material development.

There has been a sharp increase in the production of automobiles over the past decade. In 2010, one billion automobiles were in circulation worldwide. The automobile industry is one of the largest metals consumers and plays an important role in their sustainable use. Steel materials, including alloy steels that contain alloying elements (AEs) such as manganese, chromium, nickel, and molybdenum, are the main component of automobiles. The recycling of end-of-life vehicles (ELVs) significantly affects the cycling of iron, steel, and AEs. Currently, ELV recycling is performed using the electric arc furnace (EAF). In this method, losses of AEs are likely to occur because their presence is rarely considered. This study evaluated the environmental and economic benefits of alternative ELV recycling schemes, which allow more efficient utilization of AEs found in ELV-derived steel scrap (ELV-dSS). The AE contents in ELV-dSS (as car-parts) were estimated by means of a waste input-output material flow analysis (WIO-MFA) model extended for the detailed analysis of automobile composition. Using Japanese data, it was found that sorting ELV-dSS by parts can result in a significant recovery of AEs; more specifically, a 10-fold saving in AEs was achieved by sorting exhaust parts. The recoverable mass of AEs from sorted ELV-dSS was found to correspond to 8.2% of the annual consumption of AEs in Japan, as virgin resources in EAF steelmaking. ELV-dSS sorting was found to be significantly effective in the conservation of AE resources. (C) 2015 Elsevier B.V. All rights reserved.

Meeting the 2-degree global warming target requires wide adoption of low-carbon energy technologies. Many such technologies rely on the use of precious metals, however, increasing the dependence of national economies on these resources. Among such metals, those with supply security concerns are referred to as critical metals. Using the Policy Potential Index developed by the Fraser Institute, this study developed a new footprint indicator, the mining risk footprint (MRF), to quantify the mining risk directly and indirectly affecting a national economy through its consumption of critical metals. We formulated the MRF as a product of the material footprint (MF) of the consuming country and the mining risks of the countries where the materials are mined. A case study was conducted for the 2005 Japanese economy to determine the MF and MRF for three critical metals essential for emerging energy technologies: neodymium, cobalt and platinum. The results indicate that in 2005 the MFs generated by Japanese domestic final demand, that is, the consumption-based metal output of Japan, were 1.0 x 10(3) t for neodymium, 9.4 x 10(3) t for cobalt, and 2.1 x 10 t for platinum. Export demand contributes most to the MF, accounting for 3.0 x 10(3) t, 1.3 x 10(5) t, and 3.1 x 10 t, respectively. The MRFs of Japanese total final demand (domestic plus export) were calculated to be 1.7 x 10 points for neodymium, 4.5 x 10(-2) points for cobalt, and 5.6 points for platinum, implying that the Japanese economy is incurring a high mining risk through its use of neodymium. This countrys MRFs are all dominated by export demand. The paper concludes by discussing the policy implications and future research directions for measuring the MFs and MRFs of critical metals. For countries poorly endowed with mineral resources, adopting low-carbon energy technologies may imply a shifting of risk from carbon resources to other natural resources, in particular critical metals, and a trade-off between increased mining risk and deployment of such technologies. Our analysis constitutes a first step toward quantifying and managing the risks associated with natural resource mining.

The aim of this article is to propose a method for forecasting future secondary material flows by combining a product lifetime distribution analysis with a waste input-output analysis and present a simple case study of automobiles. The case study demonstrates that the proposed method enables us to estimate replacement demand of new vehicles, number of end-of-life (EOL) vehicles arising from the aging of vehicles, volume of shredder scraps recovered from EOL vehicles, and volume of shredder scraps required to meet final consumption in the future.

Understanding the industrial structure of a national or regional economy is one of the central issues in economics. The triangulation of an input–output table (IOT) can be employed to understand the production structure of an economy. Inter-temporal and inter-regional comparisons of multiple IOTs have addressed interesting and important issues pertaining to international trade, economic growth, and inter-industry relationships in the economy. Rank correlation coefficients between sector rankings obtained by solving optimization problems have been utilized to quantify similarities among production structures. However, it is well known that calculated rank correlations might be weak even if underlying structures are similar because the optimization problem inherently has multiple optimal solutions, thus leading to erroneous interpretations. This paper proposes a new method to triangulate IOTs based on mixed integer programs (MIPs) for comparing the production structures of multiple economies. The proposed new method does not suffer from non-uniqueness of optimal solutions and is consistent with maximization of the Kendall rank correlation coefficient. The application of the proposed method to the Japanese economy demonstrates stability of the Japanese production structure during 1995–2005. Comparisons of triangulated IOTs further reveal similarities in production structures of the Chinese, Japanese, and the U.S. economy for the year 2009. Electronic Supplementary Material The online version of this article (doi:10.1186/2193-2409-3-2) contains supplementary material. JEL Classification: C61, C67, L16.

This study, encompassing 231 countries and regions, quantifies the global transfer of three critical metals (neodymium, cobalt, and platinum) considered vital for low-carbon technologies by means of material flow analysis (MFA),. using trade data (BACI) and the metal contents of trade commodities, resolving the optimization problem to ensure the material balance of the metals within each country and region. The study shows that in 2005 international trade led to global flows of 18.6 kt of neodymium, 154 kt of cobalt, and 402 t of platinum and identifies the main commodities and top 50 bilateral trade links embodying these metals. To explore the issue of consumption efficiency, the flows were characterized according to the technological level of each country or region and divided into three types: green ("efficient use"), yellow ("moderately efficient use"), and red ("inefficient use"). On this basis, the shares of green, yellow, and red flows in the aggregate global flow of Nd were found to be 1.2%, 98%, and 1.2%, respectively. For Co, the respective figures are 53%, 28%, and 19%, and for Pt 15%, 84%, and 0.87%. Furthermore, a simple indicator focusing on the composition of the three colored flows for each commodity was developed to identify trade commodities that should be prioritized for urgent technical improvement to reduce wasteful use of the metals. Based on the indicator, we discuss logical, strategic identification of the responsibilities and roles of the countries involved in the global flows.

In this paper, we develop a new approach that combines the spectral clustering method and input-output analysis to detect environmentally important supply chain clusters. The newly developed method was applied to automobile manufacturing in Japan, and major clusters with high energy intensities in the automobile supply chain were identified. This paper proposes that the car manufacturers will be able to regularly publish their life-cycle assessment reports with a focus on the indirect energy consumptions within the critical supply chains and request key auto-part manufacturers in the cluster to reduce the indirect consumptions through the relevant supply chain engagement.

This paper proposes an optimal combinatorial method for finding groups of industries with relatively large CO2 emissions through industrial relations. Using an economic input-output table, we estimated a non-symmetric matrix describing how much CO2 is emitted in producing the commodity of industry i, which was purchased to produce commodity of industry j, to meet the final demand for a specific commodity. A symmetric strength of relations matrix describing the CO2 emissions associated with the industrial relations was further estimated using the non-symmetric matrix. The strength of relations matrix can be viewed as a representation of the supply-chain network of the final commodity. In this study, we estimated the strength of relations matrix associated with the final demand for automobiles and applied the multiway cut approach using nonnegative matrix factorization to the matrix in order to find environmentally important industry clusters in the Japanese automobile supply chain. According to our empirical results, the optimal number of industry clusters is 19, and 4 industry clusters are playing a key role in CO2 emission reduction. © 2013 Elsevier B.V.

Steel is not elemental iron but rather a group of iron-based alloys containing many elements, especially chromium, nickel, and molybdenum. Steel recycling is expected to promote efficient resource use. However, open-loop recycling of steel could result in quality loss of nickel and molybdenum and/or material loss of chromium. Knowledge about alloying element substance flow is needed to avoid such losses. Material flow analyses (MFAs) indicate the importance of steel recycling to recovery of alloying elements. Flows of nickel, chromium, and molybdenum are interconnected, but MFAs have paid little attention to the interconnected flow of materials/substances in supply chains. This study combined a waste input-output material flow model and physical unit input-output analysis to perform a simultaneous MFA for nickel, chromium, and molybdenum in the Japanese economy in 2000. Results indicated the importance of recovery of these elements in recycling policies for end-of-life (EoL) vehicles and constructions. Improvement in EoL sorting technologies and implementation of designs for recycling/disassembly at the manufacturing phase are needed. Possible solutions include development of sorting processes for steel scrap and introduction of easier methods for identifying the composition of secondary resources. Recovery of steel scrap with a high alloy content will reduce primary inputs of alloying elements and contribute to more efficient resource use. © 2013 American Chemical Society.

Metals can in theory be infinitely recycled in a closed-loop without any degradation in quality. In reality, however, open-loop recycling is more typical for metal scrap recovered from end-of-life (EoL) products because mixing of different metal species results in scrap quality that no longer matches the originals. Further losses occur when meeting the quality requirement of the target product requires dilution of the secondary material by adding high purity materials. Standard LCA usually does not address these losses. This paper presents a novel approach to quantifying quality- and dilution losses, by means of hybrid input-output analysis. We focus on the losses associated with the recycling of ferrous materials from end-of-life vehicle (ELV) due to the mixing of copper, a typical contaminant in steel recycling. Given the quality of scrap in terms of copper density, the model determines the ratio by which scrap needs to be diluted in an electric arc furnace (EAF), and the amount of demand for EAF steel including those quantities needed for dilution. Application to a high-resolution Japanese IO table supplemented with data on ferrous materials including different grades of scrap indicates that a nationwide avoidance of these losses could result in a significant reduction of CO2 emissions.

To build a life cycle assessment (LCA) database of Japanese products embracing their global supply chains in a manner requiring lower time and labor burdens, this study estimates the intensity of embodied global environmental burden for commodities produced in Japan. The intensity of embodied global environmental burden is a measure of the environmental burden generated globally by unit production of the commodity and can be used as life cycle inventory data in LCA. The calculation employs an input-output LCA method with a global link input-output model that defines a global system boundary grounded in a simplified multiregional input-output framework. As results, the intensities of embodied global environmental burden for 406 Japanese commodities are determined in terms of energy consumption, greenhouse-gas emissions (carbon dioxide, methane, nitrous oxide, perfluorocarbons, hydrofluorocarbons, sulfur hexafluoride, and their summation), and air-pollutant emissions (nitrogen oxide and sulfur oxide). The uncertainties in the intensities of embodied global environmental burden attributable to the simplified structure of the global link input output model are quantified using Monte Carlo simulation. In addition, by analyzing the structure of the embodied global greenhouse-gas intensities we characterize Japanese commodities in the context of LCA embracing global supply chains.

In recent years, greenhouse gas emission controls that incorporate the supply chains of products and services, thereby emphasizing the role of consumers rather than producers, have been drawing increasing attention. A country's consumption-based emissions, including those due to global supply chains, reflect the total emissions on which the national economy relies. To design effective emissions control strategies there is therefore an urgent need for countries to elucidate the structural relationship between their domestic economy and emissions occurring through global supply chains. Here we consider the structural characteristics of consumption-based emissions in Japan, which in 2005 totaled 1675 Mt CO(2)eq. Outside the country the Japanese economy generated global emissions of 541 Mt CO(2)eq, 35.7% of which were UNFCCC Annex I emissions and 64.3% were non-Annex I and other emissions. This figure of 64.3% reveals that Japan is actually relying to a considerable degree on emissions that are subject to no international obligations. We identify key economic contributors to consumption-based emissions at the commodity level and specify items of household expenditure that are effective options for both financial savings and emissions reduction. We then discuss the importance of emissions control for evolving toward a "carbon-debt-free country".

The operation of an economy is supported by the stock of materials in the form of durables and infrastructure such as machinery, equipment, buildings, and structures. The amount of durables and infrastructure or "capital stock" in the economy is of great interest in the literature of economics, and is usually measured in monetary terms based on the data on capital expenditure. In spite of its wide use by economists, this measure of "capital stock" is of very limited use for sustainable management of material stock because of its neglect of physical properties such as the mass and material composition. This paper proposes a new method of measuring the stock of long-lived durables and infrastructure in terms of the mass of its materials. This method is based on the WIO-MFA method [S. Nakamura et al. J. Ind. Ecol. 11 (2007) 50-63] and the capital formation matrix that is one of the supplementary tables of the input-output table. The method is applied to the Japanese input-output data with 400 sectors, with 9 types of metals (iron, ferroalloy, copper, zinc, lead, tin, aluminum, silver, and gold) and 8 types of plastics (thermo-setting resins, PE (low), PE (high), PS, PP, PVC, high-performance resins, and other resins) occurring as materials. It was found that substantial variations exist among sectors while fixed capital formation in the year 2000 weighs 518 kg per million Japanese yen on average in metals and plastics.

Identification of the flow of materials and substances associated with a product system provides useful information for Life Cycle Analysis (LCA), and contributes to extending the scope of complementarity between LCA and Materials Flow Analysis/Substances Flow Analysis (MFA/SFA), the two major tools of industrial ecology. This paper proposes a new methodology based on input-output analysis for identifying the physical input-output flow of individual materials that is associated with the production of a unit of given product, the unit physical input-output by materials (UPIOM). While the Sankey diagram has been a standard tool for the visualization of MFA/SFA, with an increase in the complexity of the flows under consideration, which will be the case when economy-wide intersectoral flows of materials are involved, the Sankey diagram may become too complex for effective visualization. An alternative way to visually represent material flows is proposed which makes use of triangulation of the flow matrix based on degrees of fabrication. The proposed methodology is applied to the flow of pig iron and iron and steel scrap that are associated with the production of a passenger car in Japan. Its usefulness to identify a specific MFA pattern from the original 10 table is demonstrated.

Vehicle replacement schemes such as the "cash for clunkers" program in the U.S. and the "scrappage scheme" in the UK have featured prominently in the economic stimulation packages initiated by many governments to cope with the global economic crisis. While these schemes were designed as economic instruments to support the vehicle production industry, governments have also claimed that these programs have environmental benefits such as reducing CO(2) emissions by bringing more fuel-efficient vehicles onto the roads. However, little evidence is available to support this claim as current energy and environmental accounting models are inadequate for comprehensively capturing the economic and environmental trade-offs associated with change&apos;s in product life and product use. We therefore developed a new dynamic model to quantify the carbon emissions due to changes in product life and consumer behavior related to product use. Based on a case study of Japanese vehicle use during the 1990-2000 period, we found that extending, not shortening, the lifetime of a vehicle helps to reduce life-cycle CO(2) emissions throughout the supply chain. Empirical results also revealed that even if the fuel economy of less fuel-efficient ordinary passenger vehicles were improved to levels comparable with those of the best available technology, i.e. hybrid passenger cars currently being produced in Japan, total CO(2) emissions would decrease by only 0.2%. On the other hand, we also find that extending the lifetime of a vehicle contributed to a moderate increase in emissions of health-relevant air pollutants (NO(x), HC, and CO) during the use phase. From the results, this study concludes that the effects of global warming and air pollution can be somewhat moderated and that these problems can be addressed through specific policy instruments directed at increasing the market for hybrid cars as well as extending lifetime of automobiles, which is contrary to the current wisdom.

This study proposes a method of combining a waste input output material flow analysis (WIO-MFA) model with trade statistical data to identify the flows of substances embedded in trade commodities. We focused on the case of Japan as a typical processing and trading country, and we estimated each mass of iron and aluminum embedded in the imports and exports of 300 product items categorized in the WIO-MFA. We found that iron ore imported from Australia, Brazil, and India as a raw material is processed and exported to South Korea, China, and other Asian countries as steel materials and to the United States as steel materials and automobiles. Primary aluminum imported from Russia, Australia, and Brazil as a raw material is processed and exported to Asia as rolled materials and to the United States as rolled materials and automobiles.

This paper proposes a new method for evaluating the eco-efficiency of a household based on Factor X, which was proposed by Yamamoto and colleagues in 1999. We had proposed methods for evaluating Factor X of a household which consists of a building and home appliances, and implemented empirical evaluations. However, there remained the following two issues to be considered. One is how to quantify the function of a household. The other is how to take account of the so-called synergy effects. It proposes the method for calculating the overall functions of one household using the purchasing price as a weighting coefficient. This method is the same as Laspeyres quantity index in economics fields. As a synergy effect, the insulating effect in the building, etc. are considered. The result showed that the annual greenhouse gas emission of a typical household drastically decreased by 52.2% from 1990 to 2009 while the aggregated function of the household slightly decreased by 0.2% during the same period so that Factor X was 2.1 with respect to global warming. It was thus shown quantitatively that Factor X of households in Japan presumably improved during the period although only limited assessments were implemented.

This paper is concerned with the main activities of Japan&apos;s &apos;Disclosure of CO(2) emissions&apos; programme, aimed at illustrating the CO(2) emissions associated with consumer products as a &apos;carbon footprint&apos; (CF). Although the current, provisional guidelines for calculating product carbon footprints specify that only the bottom-up approach is to be used for this purpose, this paper presents useful applications of input-output analysis that can improve the reliability of the method considerably, by taking full advantage of the strengths of input-output analysis. To this end, we first estimated the global carbon footprint (GCF) of food and consumables in Japan, using a global link input-output (GLIO) model comprising 804 economic sectors in Japan and 230 foreign countries and regions. By visualizing the GCF on a world map, the global distribution (including Middle East and African countries) of the induced CO(2) emissions of each of the Japanese sectors were identified. To investigate the scope for reducing the data collection burden for CF practitioners, GCFs were compared with CFs obtained using a single-region input-output model. This showed that there are certain commodity groups with a CF equating to 70% to over 90% of the corresponding GCF, even if the imported goods used for producing a Japanese domestic product are considered environmentally equivalent to their domestically produced counterparts. Furthermore, it was identified which data should preferably be collected by the bottom-up approach to secure CO(2) emissions coverage greater than a certain predefined level and keep data and labour costs at a minimum.

A general analytical model of materials flow analysis (MFA) incorporating physical waste input-output is proposed that is fully consistent with the mass balance principle. Exploiting the triangular nature of the matrix of input coefficients, which is obtained by rearranging the ordering of sectors according to degrees of fabrication, the material composition matrix is derived, which gives the material composition of products. A formal mathematical definition of materials (or the objects, the flow of which is to be accounted for by MFA) is also introduced, which excludes the occurrence of double accounting in economy-wide MFAs involving diverse inputs. By using the model, monetary input-output (IO) tables can easily be converted into a physical material flow account (or physical input-output tables [PIOT]) of an arbitrary number of materials, and the material composition of a product can be decomposed into its input origin. The first point represents substantial saving in the otherwise prohibitive cost that is associated with independent compilation of PIOT. The proposed methodology is applied to Japanese IO data for the flow of 11 base metals and their scrap (available as e-supplement on the JIE Web site). © 2007 by the Massachusetts Institute of Technology and Yale University.

This paper is concerned with a new integrated analytical model for evaluating environmental loads induced by consumer behavior. The model consists of two components: One is the waste input-output (WIO) model that is a consistent framework for the hybrid life-cycle assessment and life-cycle costing. The other is an economics model of consumer behavior within the constraints of limited income and time based on the concept of consumption 'technologies.' Because consumers are regarded as industrial sectors in the newly developed model, not only time and income rebound effects but also a part of the so-called economy-wide rebound effects is accounted for.

Goal, Scope and Background. This paper is concerned with a life cycle assessment (LCA) and life cycle costing (LCQ by the use of the waste input-output (WIO) quantity- and price model of air conditioners with different energy efficiency at the use phase (high-end, lowend and average models) that were available in Japan as of winter 2002. The functional unit is an air conditioner of the 2.5kW type that is used for 10 years, and then subjected to an end-of-life (EoL) process that is consistent with the Japanese law on the recycling of appliances.
Methods. This is the first simultaneous application of the WIO methodology to an LCA and LCC over the entire life-cycle of a product including the use phase, and represents a methodological extension (in the sense of considering the use phase) and integration (in the sense of a simultaneous application) of previous studies by us (Kondo and Nakamura, Int J LCA 2004, Nakamura and Kondo, Ecol Econ 2006). The main body of data is provided by the WIO table for the year 2000, an update of the previous table for 1995 that was used in the above WIO studies. Compared with the WIO table for 1995 that consisted of only about 80 industry sectors, the current one consists of about 400 industry sectors, and includes air conditioner as a separate sector. The data on the purchase price and efficiency of air conditioners indicate wide variations: the cheapest one (the lowend model) costs half of the most expensive one (the high-end model), but its efficiency is about half of the latter.
Results and Discussion. When the cost in the use and EoL phases is included, the low-end model becomes the most expensive one, and the high-end model with the highest purchase cost the least expensive. This reversal of the relative cost levels is attributed to the difference in the efficiency in the use phase. A sensitivity analysis indicates that a reduction of the electricity price in the use phase by about 40% does not alter the significant superiority of the high-end model over the low-end model. In spite of the largest amount of input in the production phase, the high-end model performs the best in terms of both global warming potential (GWP) and landfill, while the low-end model performs the worst. The use phase generates the largest amount of waste for landfill across the three models, the largest component of which is flyash generated from coal firing power plants. A possible internalization of externality in the form of carbon tax was found to work in favor of the high-end model. The cost advantage of the high-end model, however, is sensitive to the rate of discounting of future costs: discounting at 15% diminishes its advantage over the low-end model.
Recommendation and Perspective. The results indicate the effectiveness of the pricing based on the life cycle cost for achieving sustainability, that is, for promoting the shift of the demand away from appliances with low environmental performance to the one with higher environmental performance. Acceptance by society of pricing based on life cycle costing would require, among other things, an economywide standardization of the LCC concept (in a manner analogous to ISO-LCA) that can be used complementary to ISO-LCA.

Goal, Scope and Background. It has been recognized that LCA has a limitation in assessing open cycle recycling of materials because of inevitable subjective judgments in setting system boundary. According with the enforcement of recycling laws, there has been a rapid increase in recycling ratio of materials at the end-of-life of products in many industrialized countries. So, materials' life cycle is getting more complicated, which makes it difficult to quantify the environmental impacts of materials used in a product in an appropriate way. The purpose of this paper is to develop a methodology to calculate the average number of times a material is used in a society from cradle to grave. The method developed in this paper derives the average number of times material is used; this value could be used for allocation of environmental burdens of virgin material as well as an indicator for assessing the state of material,use in a certain year, based on material flow of material in that year.
Main Features. Our methodology is based on Markov chain model using matrix-based numerical analysis. A major feature of this method is that it creates transition probability matrices for a material from the way in which the material is produced, consumed, and recycled, making it possible to simply elicit indicators that assess the status of material use in products in society. Our methodology could be an alternative method to derive the average number of times material is used, which could be used for allocation of environmental burdens of virgin material.
Results and Discussions. The methodology was applied to hypothetical examples of material flows, in which a virgin material was produced and used in products, recycled and finally landfilled. In some cases, closed loop and open loop recycling of materials existed. The transition probability matrix was created for each material flow, and how many times a virgin material is used in products until all of the elements are ultimately landfilled.
Conclusions. This methodology is applicable to a complicated material flow if the status of residence of a material and its flow in a society can be figured out. All the necessary data are the amount of virgin material production, amount of the material used in products, recycling rate of the material at the end of life of each product, the amount of scrap of the material that are used for products. In Part 2 of this paper, case studies for steel were conducted.

However excellent a product may be environmentally, it would not come into wide use in the economy to realize its environmental load reducing potential unless it is also economically affordable. Life-cycle costing (LCC) is a tool to assess the cost of a product over its entire life cycle, and can be regarded as an economic counterpart of LCA. A combined use of LCA and LCC would be imperative for assessing the sustainability of a product or product systems in the economy. This paper presents a new methodology of LCC which gives the cost and price counterpart of the hybrid LCA tool (Waste Input-Output, WIO) that was developed by Nakamura and Kondo (2002) [Nakamura, S., Kondo, Y., 2002. Input-output analysis of waste management. Journal of Industrial Ecology 6 (1), 39-63.1]for LCA of waste management. Building upon the preceding LCA study by Kondo and Nakamura (2004) [Kondo, Y., Nakamura, S., 2004. Evaluating alternative life-cycle strategies for electrical appliances by the waste input-output model. International Journal of Life Cycle Assessment 9 (4), 236-246.], the applicability of the methodology is illustrated by a case study of electric appliances under alternative end-of-life scenarios: landfilling, intensive recycling that is consistent with the Japanese law on the recycling of appliances, and an advanced form of intensive recycling augmented by Design for Disassembly (DfD). Application of the proposed LCC methodology indicates that while the life-cycle cost is the highest under intensive recycling and the lowest under landfilling, the cost of recycling can be reduced by appropriate implementation of MD. The possible introduction of a carbon tax is also found to significantly reduce the cost disadvantage of recycling against landfilling. Given the high level of environmental load associated with landfilling and the possible introduction of carbon taxes, Design for Environment or EcoDesign emerges as a strategy of vital importance to achieve the sustainability of appliances. (c) 2005 Elsevier B.V. All rights reserved.

The extension of the waste input-output (WIO) model to analyze households' sustainable consumption patterns is presented in this article. We estimate direct and indirect emission loads induced by household consumption by the WIO model. The WIO model is much more suitable for the analysis of sustainable consumption than the conventional input-output model because it can deal with the disposal stage of consumed goods as well as the purchase and use stages. A simple method for evaluating income rebound effects is also introduced. As indicators of environmental loads, we estimate carbon dioxide (CO 2) emissions and landfill consumption induced by house-hold consumption. The model is applied to some typical sustainable consumption scenarios: shifting transportation modes from a private car to public transportation, the longer use of household electric appliances, and eating at restaurants instead of cooking at home. We found that the income rebound effects should be considered to evaluate environmental loads induced by different consumption patterns. © 2005 by the Massachusetts Institute of Technology and Yale University.

This paper is concerned with a decision analytic extension of the waste input-output model, based on the method of linear programming. The resulting model, which is named the waste input-output linear programming model, allows one to automatically obtain an 'optimal' waste management and recycling strategy from among a given set of alternative feasible strategies. The model can thus explore the extent to which a given measure of eco-efficiency can be maximized by an appropriate combination of existing (technological and resource) potentials. An application to Japanese data is also presented. © 2005 The International Input-Output Association.

Effects of alternative life cycle strategies of end of life electrical home appliances (EL-EHA) on the emission of CO(2), landfill volume, and the level of employment are evaluated by the waste input-output model. Extension of product life with functional upgradability is found effective to reduce the environmental effects without having negative impact on employment.

Goal, Scope and Background. In 2001, a new law on the recycling of end-of-life electric home appliances (EL-EHA) was put into effect in Japan; it was the first legislation of its sort in the world, and deserves to be called the 'Japan model.' This article is concerned with the LCA of alternative life-cycle strategies for EL-EHA, which consist of recycling as prescribed by the law, 'ecodesign' strategies such as the implementation of design for disassembly (DfD) and the extension of product life (EPL), with and without ex-post functional upgradability, and the once-dominant treatment methods such as landfilling and simple shredding.
Methods. We use the waste input-output (WIO) analysis, a new method of hybrid LCA that was developed by the authors [I]. The WIO extends the conventional input-output analysis to explicitly take into account the interdependence between the flow of goods and the flow of waste in the whole economy, and. hence provides an optimal platform for LCA involving waste treatment and recycling. Furthermore, the WIO enables us to evaluate not only environmental impacts, but also economic: impacts such as sectoral output and employment. Our analysis is based on the WIO table for 1995 and detailed process data. on recycling.
Results and Discussion. Recycling was found to outperform the 'traditional' treatment method strategy with regard to the reduction of CO2 emission, landfill consumption, and the demand for abiotic resources. Thanks to efficient utilization of the existing retail network system, it was also found to be more efficient economically. Additional implementation of DfD and the associated increase in the quality of recovered materials (plastics) were found to augment the positive environmental impacts of recycling. The EPL without upgrading resulted in a significant reduction in the environmental impacts, but also in the level of employment. On the other hand, the EPL with upgrading was found to outperform the recycling strategy in terms of environmental impacts without having significant negative economic impacts.
Conclusion and Recommendation. Recycling of EL-EHA, as prescribed by the Japanese law on the recycling of EL-EHA, was found to be effective in reducing CO, emission, depletion of abiotic resources, generation of waste, and landfill consumption, provided the rate of retrieval remains at a high level. Our results also indicate the possible effectiveness of ecodesign strategy toward the realization of a sustainable economy.

A decision analytic model of life cycle assessment (LCA) for waste management based on the waste input-output (WIO) model is presented. The resulting WIO-LP model can help environmental decision making with regard to choosing an "optimal" waste management from among a set of possible technological alternatives to meet given policy objectives under consideration of given physical, economic, and institutional constraints. Its implementation to Japanese data reveals the presence of a trade-off relationship between the reduction of CO2 emission and the consumption of landfill capacity. © 2004, The Institute of Electrical Engineers of Japan. All rights reserved.

Economic and emission effects of alternative life-cycle strategies for electric home appliances were analyzed by use of waste input-output (WIO). The strategies consist of (1) landfilling, (2) conventional shredding with iron recovery, (3) integrated recycling with the recovery of metals, glass, and plastics, and (4) extension of products lives without and with increased maintenance and updating activities. It was found that strategy 3 outperformed strategies 1 and 2 in terms of both CO2 emission and landfill consumption. The result was robust to the variation of transport conditions. The overall increase in labor cost under strategy 3 turned out almost neutral. Strategy 4 outperformed strategy 3 in terms of environmental effects. The extent to which the reduced sales of new appliances were compensated by the increased demand for maintenance was found to have significant effects on the level of employment.

We study the rental office market in the Tokyo central business district by estimating hedonic equations for the office rent for 1985-94 fiscal years. This period includes the "Bubble" of asset prices, followed by its deflation. We find that the characteristics related to transportational conveniences are less effective in explaining office rents than the characteristics related to the agglomeration of offices and the amenity characteristics of the office buildings themselves. Using a skewed error-term specification, we show that the discount in rental transactions is not irrelevant. The hedonic office rent indices and possible policy implications are also presented. JEL Classification Numbers: L85, R32.

In 1998, the Japanese government passed a law for the recycling of specified kinds of electrical home appliances, which is to be put in full operation in 2001. Under the law, the manufacturers of TV sets, refrigerators, washing machines, and air conditioners, who operate in Japan, are obliged to recycle specified percentage of discarded appliances. While the recycling is said to be technically feasible, uncertainty remains with respect to its overall effects on the environment and economy. Using the Waste Input-Output Model (WIO, [1]) we evaluated these effects, and found that the landfill consumption and carbon dioxide emission could be reduced without reducing the level of employment.

Using a model that represents global supply-chain networks, we identified supply-chain clusters with high CO2 emissions within more than 300 million individual supply chains. We distinguished 4756 significant CO2 clusters and found that in 2008, global supply-chain networks associated with U.S. construction demand included relatively large CO2 clusters in China, accounting for 10% of the U.S. CO2 footprint. Due to the sensitivity issue, there is a danger of overfitting of the results. In order to confirm the robustness and stability of the obtained clusters, we proposed a simulation-based experiment. We further developed an economic network analysis to find environmentally critical transmission sectors, transactions and paths in global supply chain networks. The edge betweenness centrality in the global supply chain networks is newly formulated. High-priority supply-chain clusters were visualized using both edge betweenness centrality and vertex betweenness centrality

A global link input-output model of multiregional input-output model, which combined global material flow data on metal resources and Japanese input-output table, measured material footprints (MF) of the resources and greenhouse gases emissions induced by final demand in Japan through the international supply chain. Mining risk on each metal resource was also quantified by using the political risk of mining countries and the global market concentration of the metal output, and attribution of the mining risk to Japanese economy was calculated based on the magnitude of the Japanese MF. In addition, focusing on changes in the household composition and the population the due to the declining birth rate and the aging population, the household consumption by household type from 2005 to 2035 were estimated and employed to analyse the future changes in the consumption-based GHG and MFs of rare metals associated with household consumption in Japan

We developed a mathematical model and applied it to visualization of supply chains, which encourages exchange of views among stakeholders and facilitates decision making to promote an effective reduction of greenhouse gas emission. The developed model is an extension of a well-known method of input-output economics, called structural path analysis, with which a total emission can be disaggregated into the contributions of parts constituting a supply chain. Moreover, we improved an existing method for triangulating input-output tables, the results of which can be used to analyze economic structures and visualize supply chains, and demonstrated the usefulness of the improved method through empirical analyses

This study proposes clustering techniques for finding groups of industries with relatively large CO2 emissions through industrial relations, that is CO2 cluster. According to our empirical results, the optimal number of industry clusters from the automobile supply-chain network is 19, and 4 industry clusters are playing a key role in CO2 emission reduction. In addition, this study attempted to detect CO2 clusters from the industrial structures of Japan, U.S.A., and China by applying the environmentally-extended Asian input-output table to the clustering technique. The results show that the Japanese economy, US economy, and Chinese economy include 5 clusters, 11 clusters, and 7 clusters, respectively and reveal a variety of cluster structures in their economies

A new method for material flow analysis(MFA), termed the unit physical input-output by material(UPIOM), was developed. The UPIOM diagram can effectively visualize inter-sector material flow, in particular, when there are a lot of sectors and loops. The UPIOM diagram can be complementary to the Sankey diagram, which is well-known in the literature of MFA. In constructing the UPIOM and Sankey diagrams, it is vital to reduce information and/or place boxes representing sectors at appropriate positions. New methods for carrying out these vital steps were developed. These methods are triangulation of input-output tables, structural path analysis, and path-based matrix decomposition analysis(PMDA). These methods were applied to MFA of metal species and carbon in Japanese economy

(1) We estimated imputed costs on global environment by abatement cost and quantity of pollutants Japan discharged and by production cost and quantity of resources Japan imported. But, we excluded some resources whose imputed costs are in dispute.(2) We made an trial estimates of Japanese environmental and economic accounting of 26X27 matrix in 1990 and 1995 which include effects of economic activities on global environment.(3) According to these estimates of Japanese environmental and economic accounting which include effects on global environment, environmentally adjusted NDP of Japan increased during these five years. It does not mean sufficient condition for "economic" sustainability and any "physical" sustainability, but a kind of necessary condition for "economic" sustainability.(4) There are two approaches for measurement of national income; i.e. Hicksian income and national welfare. We showed that since environmentally adjusted NDP belongs to the former, theoretically it is a linear approximation for "true" national income, so it is not sufficient for managing environmental problems

今年度を含む研究期間(平成12-13年度)において,以下の研究を行った.1.東京中心業務地区における賃貸オフィスについてのヘドニック分析を行い,ヘドニック価格指数を推定した.特定化の誤りを避けてセミパラメトリック法を用いたが,時点ダミーが財の諸特性と平均に関して独立であることから,クロス・バリデーション,特定化検定などを実行する際の興味深い問題点が明らかになった.また,その対処方法を示した.2.ヘドニック価格指数の推定における標本選別問題,すなわち,成約したオフィスのデータだけを用いて推定した場合の推定結果に無視し難い偏りが生じる可能性を検討した.実証分析結果として,統計的検定により標本選別の存在が示されたが,ヘドニック価格指数の推定値自体への影響は大きく無いとの知見を得た.3.パネル・データが利用可能な場合の回帰微係数の新たなノンパラメトリック推定法を開発した.この推定方法は,既存の推定方法と比較して,計算が同程度にしか複雑でない,相対的により有効である,という理論的特徴を持つ.計算実験により,漸近理論に基づく理論的特徴が小標本においても確認された.4.最小絶対偏差推定量のための効率的算法を開発した.最小絶対偏差推定量は,線形計画問題の解として得られる.開発した算法は,双対単体法を改良したものであり,計算量が少ないという特徴を持つ

次の4つの分析モデル(1)〜(4)を組み合わせることにより,ライフスタイルに起因する環境影響を評価可能な統合モデルを開発した:(1)家計生産の理論に基づく消費者行動モデル,(2)家計消費部門を内生化した産業連関モデル,(3)廃棄物産業連関数量モデル,(4)廃棄物産業連関価格モデル。(1)消費者行動モデルにおいては,同じ目的(例えば摂食)を達成するための消費技術を複数(例えば内食,中食,外食)想定し,効用最大化の仮定に基づいて,所得と諸財価格が与えられたときの最適な各消費技術の稼動水準の組合せが選択されるものとした。消費者の行動において,所得と時間に関する制約が常に等式で満たされることから,所得に関するリバウンド効果および時間に関するリバウンド効果を含めた環境影響評価が可能となっている点に,このモデルの特徴がある。(2)家計消費部門の内生化により,労働供給量の選択も含めた消費者行動の考慮と,市場を介したリバウンド効果の一部を含めた環境影響評価が可能となっている。開発したモデルを応用して,自家用車と公共交通(電車,バス),内食と中食・外食の選択と,その他の消費技術の選択と環境負荷との関係について分析を行った。自家用車利用の抑制と内食の抑制を同時に実施すると,価格と所得の変化を通じた消費者行動の変化により,安価で時間のかかる活動であるテレビを見る時間などが増加して,環境負荷低減に効果があるとの結果が得られた。移動と摂食の代替的消費技術の選択に主たる興味のある分析であるが,余暇時間も含めた選択行動が結果として得られており,余暇時間の活動を詳細に分類することにより,環境負荷低減効果の評価結果が変わることも予想されるため,この点での拡張も残された重要な課題である