CO2 emission hotspots analysis on supply chains for wooden houses in Japan.

Ninety-four percent of CO2 emissions induced by final demand in the global construction sector stem from the supply chain. Therefore, it is necessary to identify the CO2 emission hotspots within the supply chain and implement targeted reduction measures. This study proposed a supply chain clustering approach considering the functional unit of houses and identified CO2 emission hotspots within the supply chain structure of wooden houses, which accounted for approximately 90% of the total housing stock in Japan. We founded that the top ten CO2 emission clusters (i.e., emission hotspots) account for approximately 40% of the carbon footprint (38 t-CO2) of a wooden house. Specifically, the iron and steel cluster, which includes the pig iron and crude steel sectors, and the cement cluster, comprising the cement and ready-mixed concrete sectors, collectively contribute to approximately 75% of the CO2 emissions within the top 10 clusters. Therefore, the reduction of CO2 emissions from these clusters is of paramount importance. Decision-makers should promote renovation and remodeling policies for vacant houses and prioritize the reuse of foundations, predominantly constructed using steel and cement products, to reduce the supply-chain emissions from wooden houses.

Reduction of life-cycle CO2 emissions by expanding car-sharing services: A case study on Japan.

Carbon neutrality is a growing concern for all global economies. We considered the number of new and used cars registered during 2009-2018 in Japan and estimated the total number of private and shared cars, assuming that when owners abandoned their old cars, a certain percentage of the owners chose to use a car-sharing service (i.e., car rental service), instead of buying a new private car. We estimated the CO2 emissions generated during the manufacturing, driving, and disposal stages of cars, to analyze the impact of car sharing on CO2 emissions. Then, we determined the changes in the life-cycle CO2 emissions of all the cars for three car-sharing penetration rates (0, 5, and 100%), assuming that all the cars were gasoline-powered. Additionally, we analyzed how electric vehicles can optimize the proposed strategy. An increase in car-sharing services significantly reduced vehicular CO2 emissions; the decrease in CO2 emissions from private cars when owners switched to car services significantly exceeded the increase in the CO2 emissions associated with the increased number of cars. The proposed model can serve as a reliable framework to analyze the current status of CO2 emissions and simulate the future changes in car-sharing services.

Production efficiency and cost reduction potential of biodiesel fuel plants using waste cooking oil in Japan.

Biodiesel fuel (BDF) is a potentially carbon-neutral fuel that could play a potentially important role in preventing global warming. However, its high production cost poses a challenge for many BDF producers. To establish an efficient method for BDF production and increase its cost competitiveness, the production efficiencies of 35 BDF plants in Japan, which produce BDF from waste cooking oil, were evaluated. Moreover, the cost reduction potential associated with improved efficiency was estimated. The empirical analysis revealed that (1) approximately 92% of the BDF plants have inefficient production; (2) they exhibit two predominant types of inefficiencies, technical and scale inefficiencies, and (3) improvement of production inefficiency can lead to an average production cost reduction of 3.52 yen per liter of BDF. To increase the production efficiency, it is important to improve the quality of the waste cooking oil used and increase the production scale. It is recommended that operators of inefficient BDF plants learn the production activities of the most efficient plants identified in this study. Furthermore, government policies focused on efficient BDF plants are essential to increase BDF production with limited resources.

Consumption in the G20 nations causes particulate air pollution resulting in two million premature deaths annually.

Worldwide exposure to ambient PM2.5 causes over 4 million premature deaths annually. As most of these deaths are in developing countries, without internationally coordinated efforts this polarized situation will continue. As yet, however, no studies have quantified nation-to-nation consumer responsibility for global mortality due to both primary and secondary PM2.5 particles. Here we quantify the global footprint of PM2.5-driven premature deaths for the 19 G20 nations in a position to lead such efforts. G20 consumption in 2010 was responsible for 1.983 [95% Confidence Interval: 1.685-2.285] million premature deaths, at an average age of 67, including 78.6 [71.5-84.8] thousand infant deaths, implying that the G20 lifetime consumption of about 28 [24-33] people claims one life. Our results indicate that G20 nations should take responsibility for their footprint rather than focusing solely on transboundary air pollution, as this would expand opportunities for reducing PM2.5-driven premature mortality. Given the infant mortality footprint identified, it would moreover contribute to ensuring infant lives are not unfairly left behind in countries like South Africa, which have a weak relationship with G20 nations.

Critical supply chains for mitigating PM2.5 emission-related mortalities in India.

Air pollution and its health-related effects are a major concern globally, and many people die from air pollution-related diseases each year. This study employed a structural path analysis combined with a health impact inventory database analysis to estimate the number of consumption-based PM2.5 emission-related deaths attributed to India's power supply sector. We identified critical supply chain paths for direct (production) electricity use and indirect (consumption) use. We also considered both domestic and foreign final demand and its effect on PM2.5 emission-related deaths. Several conclusions could be drawn from our results. First, the effect of indirect electricity usage on PM2.5 emission-related deaths is approximately four times larger than that for direct usage. Second, a large percentage of pollution-related deaths can be attributed to India's domestic final demand usage; however, electricity usage in the intermediate and final demand sectors is inextricably linked. Third, foreign final demand sectors from the Middle East, the USA, and China contribute indirectly toward PM2.5 emission-related deaths, specifically in the rice export supply chain. The results show that the Indian government should implement urgent measures to curb electricity use in rice supply chains in order to reduce the number of PM2.5 emission-related deaths.

Determinants of technical inefficiency in China's coal-fired power plants and policy recommendations for CO2 mitigation.

This study applies data envelopment analysis (DEA) to estimate the technical efficiency (TE) and CO2 emission reduction potential of 1270 coal-fired power plants in 28 Chinese provinces and municipalities. The large dataset used in the study includes 727 combined heat and power (CHP) plants and 543 thermal power plants. Results show an average TE score of 0.57 for the CHP power plants and 0.58 for the thermal power plants, suggesting a significant potential to reduce coal consumption in both types of coal-fired plants. Total CO2 emission reduction potential was estimated to be 953 Mt-CO2, or 19% of the total CO2 emissions of China's electricity and heat producing sectors, indicating that China's coal-fired power plants have a significant potential to mitigate CO2 emissions through technological improvement. In the second stage of the study, a Tobit regression analysis was conducted to identify the determinants of TE. Factors such as the plant's annual operation rate and capacity utilization rate were found to be significant influences. Based on our results, we propose that the Chinese government create a power distribution structure that generates electricity using technologically efficient equipment in areas rich in coal resources and distributes the generated electricity to other areas of the country.

Driving propensity and vehicle lifetime mileage: A quantile regression approach.

This study aims to determine the relationship between motor vehicle lifetime and lifetime mileage, while considering drivers' propensity to drive and its effects on vehicle CO2 emissions. To do this, we analyze the relationship between lifetime mileage and vehicle lifetime for two vehicle types; a hybrid and a gasoline vehicle. We also employ a quantile regression approach to estimate the effects of drivers' propensity to drive on lifetime mileage. By estimating the CO2 emissions based on driver's propensity to drive, we analyze the effects of propensity to drive on vehicle CO2 emissions. Our results show that, for drivers who drive longer distances, the rate of decrease in average mileage grows as the vehicle age increases. Further, the results of our analysis, which considers this decrease in mileage, show that the cumulative CO2 emissions calculated under the assumption of uniform average annual mileage have been overestimated. The actual lifecycle CO2 emissions for the Prius are therefore smaller than previously reported by the previous studies, leading us to conclude that the hybrid is a more environmentally friendly vehicle than previously thought. Those of the Premio as a conventional gasoline vehicle, however, is approximately twice that. We suggest that vehicle lifecycle assessments should take into account the annual decrease in mileage demonstrated in this study.

Supply Constraint from Earthquakes in Japan in Input-Output Analysis.

Disasters often cause exogenous flow damage (i.e., the [hypothetical] difference in economic scale with and without a disaster in a certain period) to production ("supply constraint"). However, input-output (IO) analysis (IOA) cannot usually consider it, because the Leontief quantity model (LQM) assumes that production is endogenous; the Ghosh quantity model (GQM) is considered implausible; and the Leontief price model (LPM) and the Ghosh price model (GPM) assume that quantity is fixed. This study proposes to consider a supply constraint in the LPM, introducing the price elasticity of demand. This study uses the loss of social surplus (SS) as a damage estimation because production (sales) is less informative as a damage index than profit (margin); that is, production can be any amount if without considering profit, and it does not tell exactly how much profit is lost for each supplier (upstream sector) and buyer (downstream sector). As a model application, this study examines Japan's largest five earthquakes from 1995 to 2017 and the Great East Japan Earthquake (GEJE) in March 2011. The worst earthquake at the peak tends to increase price by 10-20% and decrease SS by 20-30%, when compared with the initial month's prices/production. The worst damage tends to last eight months at most, accumulating 0.5-month-production damage (i.e., the sum of [hypothetical] differences in SS with and without an earthquake [for eight months] is 50% of the initial month production). Meanwhile, the GEJE in the five prefectures had cumulatively, a 25-month-production damage until the temporal recovery at the 37th month.

Affluent countries inflict inequitable mortality and economic loss on Asia via PM2.5 emissions.

This research sets out to quantify the mortality and economic loss in individual Asian countries caused by the PM2.5 emissions induced by the consumption of the world's five highest-consuming countries (US, China, Japan, Germany, UK). In 2010 alone, the economic impact of these five countries' consumption caused a loss of almost 45 billion US dollars due to the premature deaths of more than 1 million people in Asia, including 15 thousand children younger than 5 years old. The percentage ratio of economic loss to value-added driven by consumers via trade differed greatly among the impacted countries. For the US, the highest percentage loss was 4.1% in Laos, followed by 2.0% in Bangladesh, both markedly higher than the figures for the more developed countries, such as 0.21% for Japan and 0.18% for Korea. This reflects the inequitable value chain existing between consumer countries and impacted countries, and implies that developing countries are obtaining value-added in exchange for unintentionally increased health risks, delaying their development and potentially creating a vicious circle that hinders much-needed improvements in areas like poverty reduction and public health. This inequitable situation needs to be redressed through introduction of clean energy and other types of technological assistance to help achieve United Nations Sustainable Development Goals 7, 10 and 13. Such as move is essential if premature infant deaths are to be curtailed.

Impacts of productive efficiency improvement in the global metal industry on CO2 emissions.

This study focused on 14 metal sectors of the 40 countries that are the largest CO2 emitters and developed a new analysis framework to estimate CO2 reduction potentials based on the Greenhouse Gas Protocol through efficiency improvement of the inefficient metal sector of these countries. The analysis framework was developed by combining a multi-regional input-output database with data envelopment analysis. We found that there were 20 inefficient countries in the basic iron and steel sector, which is the largest CO2 emitter among 14 metal sectors, and their efficiency improvements can contribute to reducing CO2 emissions by 354 Mt, accounting for 1.4% of the global CO2 emissions. We further proposed efficiency improvement schemes targeting the inefficient countries in order to help those countries to effectively reduce CO2 emissions according to their sectoral and national characteristics.

Role of vehicle inspection policy in climate mitigation: The case of Japan.

In 1951, the Japanese government introduced a vehicle safety inspection system and this system has an effect of shortening the 'economic' lifetimes of automobiles and increasing CO2 emissions associated with vehicle life-cycle. This study develops an integrated assessment framework by combining dynamic discrete choice analysis with life-cycle environmental accounting analysis based on a dynamic stock model. From the empirical results, we found that (1) the economic lifetime of a Prius in the benchmark model is surprisingly short, 5.07 years, due to the strict car inspection system, and this replacement cycle has contributed to increasing CO2 over time; and (2) abolishing car inspections at the third and fifth years would considerably contribute to reducing life-cycle CO2 emissions associated with Prius sold during the study period, 1997 to 2016, accounting for approximately one million tons-CO2 eq. over 20 years. Thus, we conclude that modifying the regulation policy with a focus on the car inspection system to induce car owners to keep their automobiles longer would have environmental benefits.

Global mining risk footprint of critical metals necessary for low-carbon technologies: the case of neodymium, cobalt, and platinum in Japan.

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 × 10(3) t for neodymium, 9.4 × 10(3) t for cobalt, and 2.1 × 10 t for platinum. Export demand contributes most to the MF, accounting for 3.0 × 10(3) t, 1.3 × 10(5) t, and 3.1 × 10 t, respectively. The MRFs of Japanese total final demand (domestic plus export) were calculated to be 1.7 × 10 points for neodymium, 4.5 × 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 country's 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.

MaTrace: tracing the fate of materials over time and across products in open-loop recycling.

Even for metals, open-loop recycling is more common than closed-loop recycling due, among other factors, to the degradation of quality in the end-of-life (EoL) phase. Open-loop recycling is subject to loss of functionality of original materials, dissipation in forms that are difficult to recover, and recovered metals might need dilution with primary metals to meet quality requirements. Sustainable management of metal resources calls for the minimization of these losses. Imperative to this is quantitative tracking of the fate of materials across different stages, products, and losses. A new input-output analysis (IO) based model of dynamic material flow analysis (MFA) is presented that can trace the fate of materials over time and across products in open-loop recycling taking explicit consideration of losses and the quality of scrap into account. Application to car steel recovered from EoL vehicles (ELV) showed that after 50 years around 80% of the steel is used in products, mostly buildings and civil engineering (infrastructure), with the rest mostly resided in unrecovered obsolete infrastructure and refinery losses. Sensitivity analysis was conducted to evaluate the effects of changes in product lifespan, and the quality of scrap.

Changes in the carbon footprint of Japanese households in an aging society.

As the aging and low birthrate trends continue in Japan, and as changes in the working population and consumption patterns occur, new factors are expected to have an impact on consumption-based greenhouse gas (GHG) emissions. We present the impacts of changes in the composition of Japanese households on GHG emission structures using current (2005) consumption-based accounting on the commodity sectors that are expected to require priority efforts for reducing emissions in 2035. This is done using the Global Link Input-Output model (GLIO) and domestic household consumption data and assuming that recent detailed consumption expenditures based on the Social Accounting Matrix (SAM) will continue into the future. The results show that consumption-based GHG emissions derived from Japanese household consumption in 2035 are estimated to be 1061 Mt-CO2eq (4.2% lower than in 2005). This study can be used to reveal more information and as a resource in developing policies to more meticulously and efficiently reduce emissions based on emission and import rates for each domestic and overseas commodity supply chain.

Global flows of critical metals necessary for low-carbon technologies: the case of neodymium, cobalt, and platinum.

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.

Estimates of embodied global energy and air-emission intensities of Japanese products for building a Japanese input-output life cycle assessment database with a global system boundary.

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.

Characterization of economic requirements for a "carbon-debt-free country".

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".

Role of motor vehicle lifetime extension in climate change policy.

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 CO2 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 changes 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 CO2 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 CO2 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 (NOx, 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.

Material and energy dependence of services and its implications for climate change.

As the services industry has grown and diversified, there has been a rapid rise in the share of energy and material costs in provision of services. As a result, services, which have traditionally been considered immaterial by their nature, are now absorbing substantial amounts of energy and material goods. By decomposing the CO2 emissions embodied in material goods and services, this study quantitatively analyzes the implications of energy and materials consumption in services for the change in indirect CO2 emissions by household consumers in Japan. The results show that the domestic CO2 emissions associated with the energy and material goods absorbed by services through the supply chain increased consistently during the decade 1990-2000, thereby constituting a key element in the rise in CO2 emissions due to household consumption. The energy and materials within the supply chain underlying services that have been identified as the main causes of this increase include electric power consumption, petroleum products, building renovation and repair, distribution of printed materials, plastic products and water, all of which are necessary to support the services in question. This study highlights the increasing importance of energy and materials consumption by services in the context of climate change policy.

How has dematerialization contributed to reducing oil price pressure?: a qualitative input-output analysis for the Japanese economy during 1990-2000.

The evolution of crude oil use structure and its impacts on commodity prices are examined for Japanese economy between 1990 and 2000. We found that the out-degree of the production network, indicating the extent of the pressure on prices of downstream industries in response to higher crude oil prices, decreased in several sectors between 1990 and 2000. The results by sector showed that the decrease was greatest in the chemical product- and iron and steel manufacturing sectors, which both indirectly use crude oil. The decrease in out-degree is considered to have been caused by improved efficiency in the production of oil-related products and increase in energy savings by the manufacturing facilities in these sectors. In addition, many of the sectors having a high out-degree engage in intermediate product production. Conversely, the in-degree, which represents the extent of being pressured by other sectors with increased crude oil prices, also decreased during the period between 1990 and 2000. From the result of the in-degree, this study found that dematerialization and weight reduction of final products such as "cellular phones" and "personal computers" had a marked effect on decreasing in-degree. More importantly, for the top-ranked sectors with the high out-degree and in-degree, such as "aliphatic intermediates", "chemical fertilizers", "plastic products", "hot rolled steel", "yarn and fabric dyeing and finishing", the results suggest that the pressure due to rising crude oil prices can be more effectively eased by implementing measures targeted at upstream products and sectors, while current policy measures to alleviate oil-price induced inflation are mainly targeted at downstream products such as gasoline.