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A key strategy for social development and sustainable urban expansion is building sustainable and affordable transport systems. In this study, we aim to test the validity of the environmental Kuznets curve (EKC) hypothesis and reveal the impact of infrastructure investment in transportation systems in China, Turkey, India, and Japan over the period 1995-2020 on environmental degradation. According to dynamic ordinary least squares (DOLS) method analysis, per capita GDP and per capita GDP 3 have a significant positive impact on per capita CO 2 emission, while per capita GDP 2 has a significant adverse impact on per capita CO 2 emission. These results confirm the validity of the N-shaped EKC assumption, while inconsistent with the results of the FMOLS technique, showing that per capita GDP is significantly positive, while per capita GDP 2 and per capita GDP 3 have a significant negative impact on per capita carbon emissions. Moreover, as clarified by the fully modified ordinary least squares (FMOLS) and DOLS methods, road infrastructure investment (RO), aviation infrastructure investment, trade openness, and foreign direct investment (FDI) have significant positive effects, while railway infrastructure investment (RA) has a significant negative effect on per capita carbon emission. Country-level estimates of per capita carbon emission-based DOLS strategies in the model show that only China and Japan have N-shaped EKC hypothesis. Road infrastructure investment, aviation infrastructure investment, and trade openness have significant positive effects, while railway infrastructure investment has a significant negative effect on per capita CO 2 emission in selected central and east Asian countries. The latest electrified rail systems are well thought out and less polluting, so the contribution of rail infrastructure investment to the transport mix can support sustainable and safe transport systems at city center and intercity levels and reduce environmental pollution in central and east Asian countries. Moreover, the implementation of the basic environmental settings of trade agreements should be strengthened to condense the growing impact of free trade on environmental pollution., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The significant contribution of the transportation sector to carbon dioxide emissions (CO 2 e) has become a developing concern for legislators and environmental experts. Innovation in hybrid electric vehicle-related technologies (IHVRTs) has been identified as a possible strategy for reducing CO 2 e in the transportation industry. Even though IHVRTs have the potential to reduce CO 2 e, there are insufficient studies on their impact in the top three Asian knowledge-based economies (Japan, South Korea, and Japan). This study attempts to address this gap in the literature by investigating the association between innovation in IHVRTs and CO 2 e in the top three Asian knowledge-based economies, with independent variables gross domestic product per capita (GDPPC), economic complexity (ECC), renewable energy consumption (RNEC), and financial development (FD). The model's coefficients are estimated using the augmented mean group, which considers cross-country dependencies and country-specific effects. The empirical findings indicate that IHVRTs have a substantial negative effect on CO 2 e. In addition, FD has a favorable relationship with CO 2 e, whereas ECC has a negative relationship with CO 2 e. The results also demonstrated that RNEC reduces CO 2 e, whereas the GDPPC reduces CO 2 e. The policy implications of the results imply an urgent need for additional investment in IHVRTs and a transition towards more environmentally conscious and less ecologically damaging economic activity., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

A key factor in social development and sustainable urban expansion is the establishment of sustainable and affordable transport systems. This study aims to investigate the impact of transport infrastructure investment on environmental degradation and economic growth and to test the validity of the EKC hypothesis in China, India, Russia, and Japan over the period 1995-2020. The results show that GDP has a significant positive effect, and GDP 2 and GDP 3 have significant adverse effects on environmental degradation, respectively. These results confirm the validity of the inverted U-shaped EKC hypothesis in selected emerging Asian economies. Rail infrastructure investment has significant adverse effects, while road infrastructure investment and aviation infrastructure investment have significant positive effects on environmental degradation. Likewise, the impact of investment in transport infrastructure system (roads, rail, and aviation) on economic growth is positive and statistically significant. Country-level estimates confirm the validity of the inverted U-shaped EKC hypothesis in China, India, and Russia, while the N-shaped EKC is only valid in Japan. Investments in rail infrastructure based on modern rail systems that run on electricity are believed to be less polluting in the transport mix, help create sustainable and safe transport systems, and reduce emissions at the urban and intercity levels in emerging Asian countries. In addition, the growing impact of free trade on environmental pollution should be strengthened to harmonize the strict enforcement of environmental conditions dominated by trade agreements., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The seven leading industrial countries, called the G7, are becoming a pivotal group to fulfil their emissions-reduction commitments to manage the climate crisis. This paper investigates the relationships between R&D intensity, globalization, and carbon emissions in the context of the G7 countries for the period from 1970 to 2017. Our analysis, which examines these relationships, focuses on the wavelet coherence approach to conduct time-frequency domain analyses. The empirical results show that there is heterogeneity across different time scales and frequencies for R&D intensity, globalization, and carbon emissions within each country. Specifically, R&D intensity and globalization are negatively correlated with carbon emissions for the G7 countries, except Japan, for which they are positive. The long-term correlations between R&D intensity, globalization, and carbon emissions are higher than those in the short- and medium-term periods. In addition, the multiscale connectedness network results reveal that the strongest bidirectional correlations exist between energy consumption, economic growth, and carbon emissions. Our results provide a useful reference for policymakers in the G7 countries to effectively regulate carbon emissions., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Environmental changes such as seasonality, decadal oscillation, and anthropogenic forcing may shape the dynamics of lower trophic-level organisms. In this study, 9-years (2010-2018) of monitoring data on microscopic protists such as diatoms and dinoflagellates, and environmental variables were analyzed to clarify the relationships between plankton and local/synoptic environmental changes. We found that time-series temperature increased in May, whereas it decreased in August and November. Nutrients (e.g., phosphate) decreased in May, remained unchanged in August, and increased in November from 2010 to 2018. The partial pressure of CO 2 increased in May, August, and November over time. It is notable that the change in seawater temperature (-0.54 to 0.32 °C per year) and CO 2 levels (3.6-5.7 μatm CO 2 per year) in the latest decade in the eastern Tsugaru Strait were highly dynamic than the projected anthropogenic climate change. Protist abundance generally increased or stayed unchanged during the examined period. In August and November, when cooling and decreases in pH occurred, diatoms such as Chaetoceros subgenus Hyalochaete spp. and Rhizosoleniaceae temporally increased from 2010 to 2018. During the study period, we found that locally aquacultured scallops elevated soft tissue mass relative to the total weight as diatom abundance increased, and the relative scallop soft tissue mass was positively related to the Pacific Decadal Oscillation index. These results indicate that decadal climatic forcing in the ocean modifies the local physical and chemical environment, which strongly affects phytoplankton dynamics rather than the effect of anthropogenic climate change in the eastern Tsugaru Strait., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Ninety-four percent of CO 2 emissions induced by final demand in the global construction sector stem from the supply chain. Therefore, it is necessary to identify the CO 2 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 CO 2 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 CO 2 emission clusters (i.e., emission hotspots) account for approximately 40% of the carbon footprint (38 t-CO 2 ) 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 CO 2 emissions within the top 10 clusters. Therefore, the reduction of CO 2 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., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The impact of climate change on power demand in Japan and its related CO 2 emissions is a matter of concern for the Japanese authorities and power companies as it may have consequences on the power grid, but is also of global importance as Japan is a significant contributor to global greenhouse gas emissions. In this study, we trained random forest models against daily power data in ten Japanese regions and for different types of power generation to project changes in future power production and its carbon intensity. We used climate variables, heat stress indices, and one variable for the level of human activities. We then used the models trained from the present-day period to estimate the future power demand, carbon intensity, and pertaining CO 2 emissions over the period 2020-2100 under three Shared Socioeconomic Pathways (SSPs) scenarios (SSP126, SSP370, and SSP585). The impact of climate change on CO 2 emissions via power generation shows seasonal and regional disparities. In cold regions, a decrease in power demand during winter under future warming leads to an overall decrease in power demand over the year. In contrast, the decrease in winter power demand in hot regions can be overcompensated by an increase in summer power demand due to more frequent hot days, resulting in an overall annual increase. From our regional models, power demand is projected to increase the most in most Japanese regions in May, June, September, and October rather than in the middle of summer, as found in previous studies. This increase could result in regular power outages during those months as the power grid could become particularly tense. Overall, we observed that power demand in regions with extreme climates is more sensitive to global warming than in temperate regions. The impact of climate change on power demand induces a net annual decrease in CO 2 emissions in all regions except for Okinawa, in which power demand strongly increases during the summer, resulting in a net annual increase in CO 2 emissions. However, climate change's impact on carbon intensity may reverse the trend in some regions (Shikoku, Tohoku). Additionally, we assessed the relative impacts of socioeconomic factors such as population, GDP, and environmental policies on CO 2 emissions. When combined with these factors, we found that the climate change effect is more important than when considered individually and significantly impacts total CO 2 emissions under SSP585. The contrasting results observed in the warm and cold regions of Japan can offer valuable insight into the potential future variations in energy demand and resulting CO 2 emissions on a global scale., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Global warming due to greenhouse gas emissions has led to record-breaking heat waves, torrential rains and droughts on a global scale in recent years. For this reason, people around the world are more keenly aware of the need to reduce greenhouse gas emissions. The construction industry is one of these sources of greenhouse gas emissions. A lot of ground improvement techniques have been developed and applied to improve the physical and mechanical properties of soil in order to achieve stability improvement, ground settlement control, reinforcement, liquefaction prevention, etc. These techniques use a lot of natural materials such as sand and crushed stone and industrial products such as cement. In order to reduce their environmental impact and to economize these techniques, many kinds of industrial waste and by-products have been beneficially used in many types of ground improvement techniques. In response to the growing awareness of carbon neutrality in recent years, it is necessary to further promote initiatives such as the beneficial use of the industrial materials that have been used so far and the development of new materials and construction methods to reduce carbon dioxide emissions. It is expected that various biomass materials will be applied in ground improvement techniques to enhance "negative emission technology". In this paper, recent developments and applications of certain sorts of environmentally friendly ground improvement techniques, soil densification techniques and soil stabilization techniques are briefly introduced. It is to be expected that these will be further developed and applied to contribute to the reduction in carbon dioxide emissions. [ABSTRACT FROM AUTHOR]

The current study projects the increase in surface temperature and CO 2 emissions using the EGM (1,1, α, θ) grey model for the six most significant CO 2 contributing countries, namely China, the USA, India, Russia, Japan, and Germany. The study uses time series data for surface temperature (in degree celsius) from 2010 to 2020, and CO 2 emission (metric tons per capita) data from 2009 to 2019. The empirical results show a downward trend in CO 2 emissions from Japan, Germany, the USA, and Russia by 2028. However, in the same time period, CO 2 emissions are expected to increase for India and remain nearly constant for China. This study indicates an increase in surface temperature at a significant rate in all the 6 countries: by 6.70 °C for China, 7.52 °C for Germany, 2.95 °C for India, 2.66 °C for Japan, 3.61 °C for Russia, and 13.48 °C for the USA by the end of 2028. The study compares the EGM (1,1, α, θ) grey model with the general EGM (1,1) grey model and finds that the EGM (1,1, α, θ) model performs better in both in-sample and out-of-sample forecasting. The paper also puts forward policy suggestions to mitigate, manage, and reduce increases in surface temperature as well as CO 2 emissions., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The development of globalization has separated the production and consumption of products spatially, and the international trade of products has become a carrier of embodied carbon trade. This paper adopted the perspective of value-added trade to calculate the amount of embodied carbon trade of China from 2006 to 2015 and perform a structural decomposition analysis of the changes in China's embodied carbon trade. This study found that: (1) China's embodied carbon exports are much larger than its embodied carbon imports, and there are differences between countries. China imported the largest amount of embodied carbon from South Korea, and it exported the largest amount of embodied carbon to the United States. (2) The structural decomposition analysis shows that changes in the value-added carbon emission coefficient during the study period would have caused China's embodied carbon trade to decrease, and changes in value-added trade would have caused China's embodied carbon trade to increase. Therefore, countries trading with China need to strengthen their cooperation with China in energy conservation, emission reduction, and product trade. In order to accurately reflect China's embodied carbon trade, it is necessary to calculate embodied carbon trade from the perspective of value-added trade., Competing Interests: The authors have declared that no competing interests exist.

Finding the essential factors driving carbon emissions is vital for the carbon reduction policy-making. Different from the existing research, this paper studied the separate influence of internal and external input structural changes on global carbon emissions. We applied structural decomposition analysis (SDA) to decompose the global carbon emission change into six factors: namely, the carbon emission intensity, the domestic input structure, the international input structure, consumption pattern, consumption volume and population. The results firstly showed that the contributions of different factors to global carbon emissions changed over time. In recent five years, structural changes of domestic inputs became the principle driver of decrease in global carbon emissions. Secondly, the results showed that there were significant differences for countries in their factors for carbon emissions. In India and Russia, domestic input structural change was the major contributor to the decrease in carbon emissions. In Japan and Germany, the most important factor for the increase in carbon emissions was the international input structure. Finally, the results showed the factors for carbon emission changes were correlated to economic development. The international input structural changes significantly increased carbon emissions in high-income countries. Our findings suggested that some countries such as India and Russia, improving the usage efficiency of domestic carbon-intensive products would help reducing carbon emissions. For most high-income countries such as Japan and Germany, they should reduce the dependence on the imported carbon-intensive products by turning the external input sources to countries with technology advantages. In addition, technology exportation of high-income countries would also be beneficial for the global carbon reduction., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

In the empirical literature, there is no agreement on the linkage between environmental deterioration and economic growth. Thus, this paper aims to explore the long-run and causal effects of CO 2 emissions, globalization energy usage, trade openness and urbanization on economic growth in Japan by employing new econometric techniques. The paper uses a dataset spanning from 1970 to 2015 and employs recent econometric techniques. To the best of the investigator's understanding, no prior studies have examined this linkage utilizing the wavelet coherence technique for Japan. The novelty of the wavelet is that it can capture the causality and long-run linkage between economic variables at different frequencies and periods. Thus, the study's aim is to address the following questions: (i) Is there a long-run and causal linkage between economic growth, energy usage, urbanization, CO 2 emissions, trade openness and globalization? (ii) What is the interaction between economic growth and the regressors at various frequencies and periods? The paper utilizes the ARDL, DOLS and FMOLS to catch the long-run effects, whereas the wavelet coherence technique is employed to capture the causal effects among the indicators. The outcomes of the ARDL show that urbanization, CO 2 emissions, globalization and energy usage trigger economic growth, while no significant linkage is found between trade openness and economic growth. The wavelet coherence approach reveals (i) positive co-movements between economic growth and the regressors and (ii) a one-way causality from CO 2 emissions and energy usage to economic growth., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.)

Disputes around trade inequality have been growing over the last 2 decades, with different countries claiming inequality in different terms including monetary deficits, resource appropriation and degradation, and environmental emission transfer. Despite prior input-output-based studies analyzing multidimensional trade consequences at the sector level, there is a lack of bottom-up studies that uncover the complexity of trade imbalances at the product level. This paper quantifies four types of flows, monetary, resource, embodied energy use, and embodied greenhouse gas (GHG) emissions, resulting from aluminum trade for the four economies with the highest aluminum trade, that is, the United States, China, Japan, and Australia. Results show that the United States has a negative balance in monetary flows but a positive balance in resource flows, embodied energy use, and GHG emissions. China has a positive balance in monetary and resource flows but a negative balance in embodied energy use and GHG emissions. Japan has a positive balance in all flows, while Australia has a negative balance in all flows. These heterogeneous gains and losses along the global leaders of aluminum trade arise largely from their different trade structures and the heterogeneities of price, energy use, and GHG emission intensities of aluminum products; for example, Japan mainly imports unwrought aluminum, and its quantity is 3 times that of the exported semis and finished aluminum-containing products that have similar energy and GHG emission intensities but 20 times higher prices, while Australia mainly exports bauxite and alumina that have the lowest prices, the quantity of which is 25 times that of imported semis and finished products. This study suggests that resource-related trade inequalities are not uniform across economic and environmental impacts and that trade policies must be carefully considered from various dimensions.

A critical reason for China-United States trade friction is that China has a huge trade balance, especially the trade balance of goods. However, this huge trade balance is based on the results of official statistics and does not reflect the real economic benefits and environmental costs embodied in China-US trade, where both refer to trade in value-added and embodied CO 2 emission costs, respectively. This paper calculates the trade in value-added and carbon emission transfer between China and the United States based on the World Input-Output Database. Results demonstrate that: (1) Gross trade statistics seriously overestimate China's benefits in China-US trade. The China-US trade surplus, based on gross trade statistics, is 20% higher than when based on trade in value-added accounting. (2) In China-US bilateral trade, China mainly adopts the trade model of importing intermediate products and exporting final products，whereas the United States mainly adopts the trade model of importing final products and exporting intermediate products. China's exports to the United States contain many of value-added in Korea, Taiwan, and Japan. (3) From 2000 through 2014, China maintained a large surplus of CO 2 emissions exports to the United States, and China paid a huge environmental cost in its trade with the United States. (4) In China-US trade, China's environmental costs per unit value-added is 3.02 times that of the United States., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Recent years, the energy consumption and carbon emissions released from the residential sector have increased rapidly due to the improvement of living standards. Japan, as one of the most developed countries worldwide, is found to be the fourth largest CO2 emitter in the world. Meanwhile, Japan is currently promoting social electrification from varied aspects. And this action further brings the household residential consumption to the vital place for overall energy conservation and emission reduction plans. Although electricity consumption and prediction analysis have been widely discussed. However, previous studies mainly focused on the estimation and analysis of energy consumption at the national level, without enough discussion from prefecture-level insights. To bridge this knowledge gap, this study established a factor-based bottom-up model to estimate the electricity consumption and carbon emissions during the 2015-2040 periods in the Japanese residential sector, considering the prefectural characteristics including per capita gross domestic product, population size, household size, residential floor space area, lifestyle, weather condition, and transition effect of appliance in the future. Nine scenarios that combine three levels of household size and three levels of growth of per capita gross domestic product are taken into account to estimate the electricity consumption for space heating and cooling, water heating, cooking, and appliances. Results indicate that the total residential electricity consumption will reach a peak during 2020s. The total carbon emissions will keep decreasing by 51.14-72.16 Mt between 2015 and 2040. Based on the results of this paper, policy recommendations are given for the Japanese government., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

This paper empirically investigates the effect of carbon emissions on sovereign risk? To answer this question, we use fixed effects model by using annual data from G7 advanced economies, which includes Canada, France, Germany, Italy, Japan, UK and USA, for the period from 1996 to 2014. We employ a novel extreme value theory to measure sovereign risk. The results indicate that climate change (carbon emissions) are likely to increase sovereign risk significantly. We also expand our analysis to some specific sectors, as some of the sectors emit more carbon than others. Specifically, we take top three polluting sectors namely: transportation, electricity and industry and show that they are more likely to increase the sovereign risk. Our results are robust to change in risk measures, estimation in differences and dynamic version of econometric models. Therefore, we have robust consideration that the carbon emissions significantly explain the sovereign risk., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

This paper contributes to the growing literature regarding the role of Information and Communication Technologies as well as Innovation on driving the level of carbon dioxide emissions and economic growth in context of the 21st conference of the Parties to the Climate convention (COP21). Drawing the data from 13 selected G-20 countries (including Argentina, Canada, China, France, Germany, Italy, Japan, Mexico, Republic of Korea, Russian Federation, Turkey, United Kingdom, United States) during the period of 15 years, our study achieves significant results. First, only five factors impede the carbon emissions namely energy price, foreign direct investment, technology, spending on innovation and trade openness while the remainder of determinants contribute to contamination of environment, including financial development. Second, when it comes to economic growth, information and communication technological and financial development are positive driving factors. Our results do reject the absence of Environmental Kuznets Curve (EKC) from our sample. Finally, our study empirically suggests that the work of controlling consumption of oil and environmentally friendly process including manufacture-trading in these economies will limit the amount of pollution., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

This paper explores the role of negative emissions technologies (NETs) in energy systems, bioenergy with carbon capture and storage (BECCS) and direct air capture (DAC) with geological carbon storage (DACCS) in particular, using a bottom-up energy system model TIMES-Japan that participated in the 35th study of the Stanford Energy Modeling Forum (EMF 35 JMIP) focusing on the energy transitions for the long-run climate goals. Modeling results show that large-scale deployment of NETs is essential to achieve the net-zero vision of Japan's long-term strategy, however, these NETs might not be enough in the case of the highest energy service demands. Within the feasible solution space, earlier deployment of BECCS with domestic biomass can contribute effectively to achieve the target with the support of the DACCS at the later period if both technologies are available. It shows feasible results without DACCS only in the lowest energy service demands, implying the importance of urgent research, development, and deployment of DACCS. Furthermore, this study shows that earlier deployment of DAC system with CO2 utilization in fuel production is a cost-effective way to lead the large-scale deployment of the DAC as NETs. [ABSTRACT FROM AUTHOR]

The problem of modal choice between rail and air arises as public awareness of carbon dioxide (CO) emissions by the transportation sector rises. In this paper, we answer this question quantitatively by performing an efficiency benchmarking analysis that takes into account life-cycle CO emission due to transport service provision. The paper employs nonparametric efficiency estimation methods, namely a slacks-based inefficiency measure, as well as a more conventional directional distance function approach. We apply them to a panel data set for three major railway companies and the aviation sector in Japan for the period from 1999 to 2007. Results shows that, contrary to the common argument, air transport can still be more socially efficient than rail transport, even when the environmental load due to CO emission is incorporated. This is due to the aviation sector's extremely low user cost, measured in terms of in-vehicle time. In other words, aviation is a necessary transportation mode for those with a very high willingness to pay for their time. [ABSTRACT FROM AUTHOR]

This paper is concerned with the main activities of Japan's 'Disclosure of CO2 emissions' programme, aimed at illustrating the CO2 emissions associated with consumer products as a 'carbon footprint' (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 CO2 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 CO2 emissions coverage greater than a certain predefined level and keep data and labour costs at a minimum. [ABSTRACT FROM AUTHOR]

This paper aims to offer a quantitative contribution to energy-environment policy in Japan in the aftermath of the Fukushima nuclear power accident. Since then, nuclear power energy supply has almost entirely been banned, and consequently, an intensive search for alternative forms of energy supply (ranging from fossil fuels to renewable forms of energy, such as solar or thermal power) has started. There is no clear-cut direction for energy policy, as each option involves costs and CO consequences; Japan has even withdrawn from the Kyoto protocol. A balanced energy-environment policy is difficult to achieve in the short term, and therefore, there is an urgent need for a comprehensive efficiency and performance analysis of the Japanese energy sector. A popular standard tool to judge the efficiency or performance of a decision-making unit (DMU) is a data envelopment analysis (DEA). The existence of multiple efficiency-improvement solutions has prompted much criticism in recent years. In the meantime, much progress has been made in extending this approach in several directions. An example is the euclidean distance minimisation (EDM) method, based on a generalised distance function, which serves to improve a DMU's performance by tracing the most appropriate movement towards the efficiency frontier. The EDM model is able to calculate an optimal input reduction value and an optimal output increase value in order to reach an efficiency score of 1.0, even though in reality this may be hard to achieve for low-efficiency DMUs. In contrast, high-efficiency DMUs might find it easier to reach an efficiency score of 1.0, or in the case of a super-efficiency DEA, a score of above 1.0. This paper aims to present a newly developed adjusted DEA model, emerging from a blend of the EDM and the target-oriented (TO) approach based on a super-efficiency model, for generating an appropriate efficiency-improving projection model. The TO approach specifies a target-efficiency score (TES) for inefficient DMUs. This approach can compute an input reduction value and an output increase value in order to achieve a higher TES. The abovementioned TO-EDM model will be applied to an efficiency analysis of the energy-environment interface for 10 regions in Japan. The focus will be on one input cost criterion (viz. expenditures) and two output performance criteria (viz. electricity generation and CO emission). Based on an extensive database, a comparative performance analysis of the 10 Japan regions under consideration will be pursued. [ABSTRACT FROM AUTHOR]

Using annual data from 1970 to 2014, this paper examines the effects of globalization on CO2 emissions in Japan while accounting for economic growth and energy consumption as potential determinants of carbon emissions. The structural breaks and asymmetries arising due to policy shifts require attention, and hence, an asymmetric threshold version of the ARDL model is utilized. The results show the presence of threshold asymmetric cointegration between variables. Threshold-based positive and negative shocks arising from globalization increase carbon emissions, while the impact of the latter is more profound. Energy consumption (economic growth) also has a significant positive effect on carbon emissions. Globalization, economic growth, and energy consumption significantly increase carbon emissions in the short run. We suggest that policy makers in Japan consider globalization and energy consumption as policy tools in formulating their policies regarding protecting sustainable environmental quality in the long run. Otherwise, the Japanese economy may continue to face environmental consequences such as undesirable climate change and massive warming at the micro and macro levels as a result of potential shocks arising from globalization and energy consumption. [ABSTRACT FROM AUTHOR]

Hydrofluorocarbons (HFCs) are powerful anthropogenic greenhouse gases (GHGs) with high global-warming potentials (GWPs). They have been widely used as refrigerants, insulation foam-blowing agents, aerosol propellants, and fire suppression agents. Since the mid-1990s, emissions of HFCs have been increasing rapidly as they are used in many applications to replace ozone-depleting chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) whose consumption and production have been phased out under the Montreal Protocol (MP). Due to the high GWP of HFCs, the Kigali Amendment to the MP requires the phasedown of production and consumption of HFCs to gradually achieve an 80 %–85 % reduction by 2047, starting in 2019 for non-Article 5 (developed) countries with a 10 % reduction against each defined baseline and later schedules for Article 5 (developing) countries. In this study, we have examined long-term high-precision measurements of atmospheric abundances of five major HFCs (HFC-134a, HFC-143a, HFC-32, HFC-125, and HFC-152a) at Gosan station, Jeju Island, South Korea, from 2008 to 2020. Background abundances of HFCs gradually increased, and the inflow of polluted air masses with elevated abundances from surrounding source regions were detected over the entire period. From these pollution events, we inferred regional and country-specific HFC emission estimates using two independent Lagrangian particle dispersion models and Bayesian inversion frameworks (FLEXPART-FLEXINVERT + and NAME-InTEM). The spatial distribution of the derived "top-down" (measurement based) emissions for all HFCs shows large fluxes from megacities and industrial areas in the region. Our most important finding is that HFC emissions in eastern China and Japan have sharply increased from 2016 to 2018. The contribution of East Asian HFC emissions to the global total increased from 9 % (2008–2014) to 13 % (2016–2020). In particular, HFC emissions in Japan (Annex I country) rose rapidly from 2016 onward, with accumulated total inferred HFC emissions being ∼ 114 Gg yr -1 , which is ∼ 76 Gg yr -1 higher for 2016–2020 than the "bottom-up" (i.e., based on activity data and emission factors) emissions of ∼ 38 Gg yr -1 reported to the United Nations Framework Convention on Climate Change (UNFCCC). This is likely related to the increase in domestic demand in Japan for refrigerants and air-conditioning-system-related products and incomplete accounting. A downward trend of HFC emissions that started in 2019 reflects the effectiveness of the F-gas policy in Japan. Eastern China and South Korea, though not obligated to report to the UNFCCC, voluntarily reported emissions, which also show differences between top-down and bottom-up emission estimates, demonstrating the need for atmospheric measurements, comprehensive data analysis, and accurate reporting for precise emission management. Further, the proportional contribution of each country's CO 2 -equivalent HFC emissions has changed over time, with HFC-134a decreasing and HFC-125 increasing. This demonstrates the transition in the predominant HFC substances contributing to global warming in each country. [ABSTRACT FROM AUTHOR]

Japan ranks amongst the biggest emitters of greenhouses gases in the world, but still lacks convincing policies to reach its climate targets. However, since 2005, Japan has been experimenting with cap-and-trade. By applying established environmental economics methods, this paper analyzes the most important programs, the national Japan Voluntary Emissions Trading Scheme (JVETS) and the local Tokyo Metropolitan Government Emissions Trading Scheme (TMG ETS). By doing so, the paper shows that in comparison JVETS can only be considered a pilot program with limited success, whereas the TMG ETS is more promising in design. [ABSTRACT FROM AUTHOR]

In this paper, the significance of CO 2 -free hydrogen is discussed using a long-term global energy system. The energy demand–supply system including CO 2 -free hydrogen was assumed, though there are still large uncertainties as to whether a global CO 2 -free hydrogen energy system will be deployed. System analysis was conducted using the global and long-term intertemporal optimization energy model GRAPE under severe CO 2 emission constraints. Applied global CO 2 constraints for 2050 were a 50% reduction from 1990 levels. CO 2 constraints accounting for Intended Nationally Determined Contributions (INDCs) in each region were also considered. A variety of energy resources and technologies were considered in this model. Hydrogen can be produced from low-grade coal or natural gas with CO 2 capture and electricity from renewable energy. The hydrogen CIF (cost, insurance, and freight) price for Japan was about 3.2 cents/MJ in 2030. Hydrogen demand technologies considered in this paper are hydrogen-fired power plants, direct combustion, combined heat and power (fuel cells, gas engines, and gas turbines), fuel cell vehicles, and hydrogen internal combustion engine vehicles. The majority of CO 2 -free hydrogen was deployed in the transportation sector. CO 2 -free hydrogen was utilized in the power sector, where deployment of other zero emission technology has some constraints. From an economic viewpoint, CO 2 -free hydrogen can reduce the global energy system cost. From the viewpoint of a localized region, such as Japan, deployment of CO 2 -free hydrogen can improve energy security and environmental indicators. [ABSTRACT FROM AUTHOR]

Tectonic instability may be measured directly using extensometers installed across active faults or it may be indicated by anomalous natural gas concentrations in the vicinity of active faults. This paper presents the results of fault displacement monitoring at two sites in the Bohemian Massif and Western Carpathians. These data have been supplemented by radon monitoring in the Mladeč Caves and by carbon dioxide monitoring in the Zbrašov Aragonite Caves. A significant period of tectonic instability is indicated by changes in the fault displacement trends and by anomalous radon and carbon dioxide concentrations. This was recorded around the time of the catastrophic MW=9.0 Tōhoku Earthquake, which hit eastern Japan on 11 March 2011. It is tentatively suggested that the Tōhoku Earthquake in the Pacific Ocean and the unusual geodynamic activity recorded in the Bohemian Massif and Western Carpathians both reflect contemporaneous global tectonic changes., (© The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Coastal warming, acidification, and deoxygenation are progressing primarily due to the increase in anthropogenic CO 2. Coastal acidification has been reported to have effects that are anticipated to become more severe as acidification progresses, including inhibiting the formation of shells of calcifying organisms such as shellfish, which include Pacific oysters (Crassostrea gigas), one of the most important aquaculture resources in Japan. Moreover, there is concern regarding the combined impacts of coastal warming, acidification, and deoxygenation on Pacific oysters. However, spatiotemporal variations in acidification and deoxygenation indicators such as pH, the aragonite saturation state (Ωarag), and dissolved oxygen have not been observed and projected in oceanic Pacific oyster farms in Japan. To assess the present impacts and project future impacts of coastal warming, acidification, and deoxygenation on Pacific oysters, we performed continuous in situ monitoring, numerical modeling, and microscopic examination of Pacific oyster larvae in the Hinase area of Okayama Prefecture and Shizugawa Bay in Miyagi Prefecture, Japan, both of which are famous for their Pacific oyster farms. Our monitoring results first found Ωarag values lower than the critical level of acidification for Pacific oyster larvae in Hinase, although no impact of acidification on larvae was identified by microscopic examination. Our modeling results suggest that Pacific oyster larvae are anticipated to be affected more seriously by the combined impacts of coastal warming and acidification, with lower pH and Ωarag values and a prolonged spawning period, which may shorten the oyster shipping period and lower the quality of oysters. [ABSTRACT FROM AUTHOR]

This paper examines the potential of integrated waste and utility power management over the mid-term planning horizon in Japan. Energy recovery and CO(2) emission reduction were estimated under two situations: (1) energy recovery efforts within the current waste management/power generation framework and (2) integrated waste management with sewage treatment systems and electric power industries. Scenario simulation results showed that under the current policy framework it is not feasible to achieve large energy recovery and CO(2) emission reduction, while the integrated waste management scenarios show the potential of large energy recovery which is equivalent to about an 18 million t-CO(2) emission reduction. The utilization of dry wastes for power generation at existing fossil power stations is significant in achieving the result. We also consider the effects of the 'CO(2) emission per GW generated' for electric power generation on the total CO(2) emission reduction because it varies by country and assumptions selected. Although this research did not include an economic analysis, based on estimated CO(2) emissions and energy recovery, the integrated scenarios indicate a large potential in countries that have high dependence of fossil power generation and relatively low power generation efficiency.

Many firms generate large amounts of carbon dioxide and other greenhouse gases when they burn fossil fuels in their production processes. In addition, production of raw materials and other inputs the firms procure for their operations also generates greenhouse gases indirectly. These direct and indirect greenhouse gas emissions occur in many sectors of our economies. In this paper, we first present sector-specific estimates for such greenhouse gas emissions. We then show that estimates for such sector-specific greenhouse gas emissions are often required for various types of corporate as well as public policy analyses in both domestic and international contexts. Measuring greenhouse gas emissions resulting from firms' multi-stage production processes in a multi-sector context is relevant for policies related to the Kyoto protocol, an international agreement to limit global greenhouse gas emissions. For example, since the protocol allows firms to engage in trading and offsetting of their greenhouse gas emissions across national borders, provided that emissions are correctly measured, the firms can take advantage of such trading schemes by placing their energy-intensive production facilities globally and strategically. We present several case studies which illustrate the importance of this and other aspects of greenhouse gas emissions in firms' environmental management. We also argue that our modeling and estimation methods based on input-output analyses are suitable for the types of research goals we have in this paper. Our methods are applied to data for Canada and Japan in a variety of environmental management circumstances.

Abstract: In order to gain a greater understanding of firms'' ‘environmental behaviour’ this paper explores the factors that influence firms'' emissions intensities and provides the first analysis of the determinants of firm level carbon dioxide (CO2) emissions. Focussing on Japan, the paper also examines whether firms'' CO2 emissions are influenced by the emissions of neighbouring firms and other possible sources of spatial correlation. Results suggest that size, the capital–labour ratio, R&D expenditure, the extent of exports and concern for public profile are the key determinants of CO2 emissions. Local lobbying pressure, as captured by regional community characteristics, does not appear to play a role, however emissions are found to be spatially correlated. This raises implications for the manner in which the environmental performance of firms is modelled in future. [Copyright &y& Elsevier]

The NEAT model (Nonenergy-use Emission Accounting Tables) has been developed in order to estimate CO2 emissions caused by so-called nonenergy use of fossil fuels. The model is based on material flow accounting. The model has been applied to a number of countries in order to validate and improve its use. This paper discusses the case study for Japan. The NEAT analysis suggests that emissions in 1996 were 23 Mt higher than previously estimated based on the guidelines of the Intergovernmental Panel on Climate Change (IPCC). This quantity equals 1.9% of the total Japanese greenhouse gas emission. It is recommended to adjust the Japanese emission accounting practice and to apply more detailed emission estimation methods in future years. Given similar results for other countries it is also recommended to improve the IPCC guidelines.

The Great Tohoku–Kanto earthquake and the resulting tsunami have brought considerable attention to the issue of building new nuclear power plants. In this paper we argue that nuclear power is not a sustainable solution to energy problems. First, we explore the stock of uranium-235 and the different methods, fast breeder and MOX fuel reactors, developed by the nuclear power industry to exploit this resource. Second, we show that these fuel reactors are not feasible. Third, we show that the claim that nuclear energy can be used to reduce CO2 emissions is false: the emissions from the increased water evaporation from nuclear power generation must be accounted for. In the case of Japan, water from nuclear power plants is drained into the surrounding sea, raising the water temperature which has an adverse effect on the immediate ecosystem, as well as increasing CO2 emissions from increased water evaporation from the sea. Next, a short exercise is used to show that nuclear power is not needed to meet electricity demand in Japan. Such an exercise should be performed for any country considering the construction of additional nuclear power plants. Lastly, the paper is concluded with a discussion of the implications of our paper. [Copyright &y& Elsevier]

Abstract: The environmental impact of CO2 emissions has attracted increasing attention in recent years, which has redefined the modal choice between air and rail transport. Transport service provision via railway involves less marginal environmental damage than air transport, yet it entails a higher emissions burden in its infrastructure construction stage. This paper empirically investigates the environmental burden of these two transport modes by taking into account the CO2 emissions from both transport service provision and infrastructure construction. Using a panel data set from 1999 to 2007 for three Japanese railway companies and the Japanese air transport industry, which are treated as decision-making units (DMUs), this paper estimates the social efficiency of these DMUs via a nonparametric productivity measurement method that incorporates economic bads as undesirable outputs. The aviation industry is shown to be efficient, whereas results for the railway industry are mixed: JR East is efficient, JR West is inefficient throughout the observation period, and JR Tokai substantially improved its efficiency during the period to become an efficient company in 2007. [Copyright &y& Elsevier]

abstract This paper reports the results of a full year (2000) of measurements of CO2 flux at a successional forest of mature birch and growing oak with Sasa-bamboo in Sapporo, Japan. Eddy covariance fluxes of CO2 were obtained using a closed-path infrared gas analyzer. Changes in CO2 storage under the eddy-flux measurement level were quantified using vertical profiles of the CO2 concentration. Seasonal variations in net CO2 exchange between the forest and the atmosphere are discussed in terms of both phenological developments of the forest canopy and micrometeorological variables. To estimate the annual exchange of CO2 , the net CO2 exchange data both during periods of poor turbulence and during periods of missing data were replaced by simple parametric models based on measurements of soil temperatures and photosynthetically active radiation. The corrected annual carbon sequestration estimate was 260 g C m-2 . The estimates of annual gross carbon gain and loss at the forest were 1120 and 860 g C m-2 . [ABSTRACT FROM AUTHOR]

This study evaluates the progress of efficient energy use and the control of carbon dioxide (CO2) emissions in Japan between 1990 and 2012. A new indicator of energy performance is presented called environmental energy efficiency (EEE). The EEE of manufacturing industries was measured by each prefecture in Japan. We estimated the influencing factors of EEE for each industry by applying the pooled mean group (PMG) method. Our findings are as follows: First, the Japanese manufacturing industry has not been in line with the EEE improvement goals since the adoption of the Kyoto Protocol. However, the progress of each industry was relatively consistent by region. Second, EEE tends to improve and then deteriorate or monotonically increase as economic development progresses. Third, EEE is raised by expanding industry share. Finally, EEE, which focuses on energy reduction, is likely to increase with the progress of energy-saving technology. [ABSTRACT FROM AUTHOR]

Despite the rapid market penetration of hybrid vehicles (HVs), their usage and contributions to environmental protection have not been examined by vehicle traveling data. In this paper, we analyzed Japan’s used car market data to understand how HVs are used on the street. We find GV drivers with high travel demand switched from GVs to HVs during the transition period. Despite HV owners driving much longer distances than conventional gasoline vehicle (GV) owners, they emit less carbon dioxide (CO 2 ) emissions, owing to better fuel economy. We also find that HV owners spend roughly the same amount of money annually as GV owners. However, the per-kilometer travel cost of HVs is much lower than that of GVs even if the depreciation cost of the vehicle and vehicle related taxes are included in the analysis. [ABSTRACT FROM AUTHOR]

Smart buildings that utilize innovative technologies such as artificial intelligence (AI), the internet of things (IoT), and cloud computing to improve comfort and reduce energy waste are gaining popularity. Smart buildings comprise a range of sensors to measure real-time indoor environment variables essential for the heating, ventilation, and air conditioning (HVAC) system control strategies. For accuracy and smooth operation, current HVAC system control strategies require multiple sensors to capture the indoor environment variables. However, using too many sensors creates an extensive network that is costly and complex to maintain. Our proposed research solves the mentioned problem by implementing a machine-learning algorithm to estimate unmeasured variables utilizing a limited number of sensors. Using a six-month data set collected from a three-story smart building in Japan, several extreme gradient boosting (XGBoost) models were designed and trained to estimate unmeasured room temperature, relative humidity, and CO2 concentrations. Our models accurately estimated temperature, humidity, and CO2 concentration under various case studies with an average root mean squared error (RMSE) of 0.3 degrees, 2.6%, and 26.25 ppm, respectively. Obtained results show an accurate estimation of indoor environment measurements that is applicable for optimal HVAC system control in smart buildings with a reduced number of required sensors. [ABSTRACT FROM AUTHOR]

Blast furnace technology is currently aiming at low reducing agent operation so as to decrease CO2 emissions. At the same time, the inner volume of blast furnaces has frequently been enlarged so as to increase production rate in some countries, including Japan. Operating conditions designed for low reducing agent in a large blast furnace tend to cause unfavorable phenomena such as slipping of the burden and gas channeling due to the decrease in coke rate. Mathematical models help to clarify the in-furnace phenomena under these situations. From the above backgrounds, a new model has been developed that combines Discrete Element Method with Computational Fluid Dynamics (DEM-CFD) to simulate precisely the gas flow and solid motion in a blast furnace. The present study aimed to develop a three-dimensional mathematical model based on DEM-CFD for simultaneous analysis of gas and solid flow in the whole blast furnace. The unbalanced gas flow in the case of clogging of the particular tuyere was analyzed to clarify the circumferential unevenness in the lower part of the blast furnace. Based on the combined DEM with CFD model, the non-uniform gas flow in the lower part of the blast furnace was precisely evaluated. [ABSTRACT FROM AUTHOR]

Abstract: Recently, energy service providers (ESP) have increased due to deregulation in the power market. They install energy supply equipment at their own cost and supply the necessary energy to the client. The Tokyo Metropolitan Government started Asia''s first cap-and-trade program in April 2010. This program caps energy-related carbon dioxide emissions from some 1,330 offices and factories in Tokyo. Then, ESPs have to manage the many risks of energy service project directly linked to the profits. In this paper, we describes the risk analysis and investment optimization for energy service projects using financial engineering. [Copyright &y& Elsevier]

Abstract: This paper discusses voluntary CO2 emissions reduction schemes and, in particular focuses on the voluntary plan by the Japanese airline industry. Econometric analysis identifies statistically significant improvement of 3–4% in CO2 emissions intensity (CO2/RPK) subsequent to initiation of the voluntary plan in 1998. [Copyright &y& Elsevier]

Abstract: In this paper we present the results of an integrated field and experimental study on the geochemical reactions in a sandstone reservoir at Nagaoka, Japan, where the first Japanese pilot project of CO2 geological storage is underway. Prior to the CO2 injection, we collected formation water and rock samples from the reservoir, and conducted laboratory experiments to investigate the geochemical reactions when injecting CO2 into the reservoir. About 1 year after stopping the CO2 injection, we again collected formation fluid using a Cased Hole Dynamics Tester (CHDT) at one of the three observation wells where CO2 breakthrough was confirmed by time-lapse well logging. Chemical analyses of the post-CO2 injection samples indicate a high HCO3 − concentration compared to original formation water. Concentrations of Ca, Mg, Fe, Mn and Si also increased. The field results were quite similar to the laboratory experiments on CO2–water–rock reactivity. Our results demonstrated the potential of CO2 storage by formation water dissolution and mineral trapping of CO2. [Copyright &y& Elsevier]

Abstract: The Yubari pilot at the southern part of the Ishikari coalfield of Hokkaido represents Japan''s first CO2 storage field trial in coal seams. Following a micro-pilot and two multi-well CO2 injection tests (involving an injection and a production well) between May 2004 and October 2005, a three-stage N2 flooding test, including two separate CO2 injection periods prior to and after the flooding, was performed in 2006 to evaluate the effectiveness of N2 flooding on improving well injectivity. The test showed that the daily CO2 injection rate was boosted by up to four-fold by the N2 flooding, but only temporarily. This paper reports the latest field test results and a history-matching and reservoir simulation study of the field data, using the Imperial College in-house ECBM simulator METSIM2 with its dynamic permeability modelling capability. History-matching of 2004 and 2005 multi-well field tests has shown that CO2 injection caused approximately one-order of magnitude reduction in the near wellbore permeability and thus in well injectivity. This is consistent with the reported well test results. The calibrated reservoir and permeability model was then used to evaluate the performance of the N2 flooding test. The simulation results indicate that an increase in the wellbore permeability of over two-order of magnitude (one order over the in situ permeability) is responsible for the observed dramatic short-term increase in the post-flooding CO2 injectivity. [Copyright &y& Elsevier]

Road transportation is rapidly increasing its share worldwide due to its convenience and economic merits. On the other hand, it has also brought about serious environmental impacts including CO2 emissions and essential energy security issues. This paper describes the current situation regarding those environmental issues of road transportation with its background, and countermeasures to solve the issues. Then, it discusses recent Japanese policy and measures to meet the CO2 reduction targets of the Kyoto Protocol, which is now one of the most serious issues for road transportation. [ABSTRACT FROM AUTHOR]

Today's material welfare has been achieved at the expense of consumption of finite resources and generation of environmental burdens. Over the past few decades the volume of global consumption has grown dramatically, while at the same time technological advances have enabled products with greater efficiencies. These two directions of change, consumption growth and technological advance, are the foci of the present paper. Using quantitative measures for these two factors, we define a new indicator, ‘eco-velocity of consumption’, analogous to velocity in physics. The indicator not only identifies the environmental soundness of consumption growth and technological advance but also indicates whether and to what extent our society is shifting toward sustainable consumption. This study demonstrates the practicability of the indicator through a case study in which we calculate the eco-velocities of Japanese household consumption in 2 years: 1995 and 2000. The rate of technological advance during the periods concerned is quantified in terms of the embodied carbon dioxide emission per yen of product. The results show that the current growth rate of Japanese household consumption is greater than the rate of technological advance to mitigate carbon dioxide emissions. The eco-velocities at the level of individual commodity groups are also examined, and the sources of changes in eco-velocity for each commodity are identified using structural decomposition analysis. [ABSTRACT FROM AUTHOR]

Abstract: Carbon dioxide (CO2) emissions from the passenger-car sector in Japan are increasing rapidly and should be reduced cost-effectively in order to stabilize energy-related CO2 emissions in Japan. The purpose of the present paper is to clarify the most cost-effective mix of vehicles for reducing CO2 emissions and to estimate the subsidy that is necessary to achieve this vehicle mix. For this analysis, the energy system of Japan from 1988 to 2032 is modeled using a MARKAL model. The most cost-effective mix of vehicles is estimated by minimizing the total energy system cost under the constraint of an 8% energy-related CO2 emissions reduction nationally by 2030 from the CO2 emissions of 1990. Based on the results of the analysis, hybrid vehicles are the only type of clean-energy vehicle, and their share of the passenger car sector in 2030 will be 62%. By assuming the subsidization of hybrid vehicles, the same vehicle mix can be achieved without constraining CO2 emissions. The peak of the total subsidy estimated to be necessary is 1.225 billion US$/year in 2020, but the annual revenue of the assumed 31 US$/t-C carbon tax from the passenger car sector is sufficient to finance the estimated subsidy. This suggests that we should support the dissemination of hybrid vehicles through subsidization based on carbon tax. [Copyright &y& Elsevier]

Carbon taxation affects carbon dioxide (CO2) emissions through the price of fossil fuels, and hence can also affect emissions of air pollutants. Based on this fact, this study aims at exploring the impact of the carbon tax in Japan on various pollutants' emissions, using a regression-based approach. The main contribution of this study is to assess the impact of a tax that is mainly directed at cutting CO2, on other gases, namely sulphur dioxide (SO2), suspended particulate matter (SPM), carbon monoxide (CO) and nitrogen oxide (NOX), as well as analyzing the impact of this tax on different sectors of the Japanese economy. Our results imply that the introduction of the carbon tax in Japan effectively reduced non-CO2 greenhouse gases (GHGs) and pollutants, even when controlling for demographic and economic variables. The results of this study can be explained by a partial decoupling of fossil fuel consumption and GHG emissions, possibly through investment in anti-pollution measures. [ABSTRACT FROM AUTHOR]

Combined NO2 and CO2 observations have the potential to constrain the identification of the locations and strength of urban CO2 emissions, in particular, point sources such as power plants. We report the first results of airborne spectroscopic NO2 and CO2 observations over an urban area in Japan in February 2018. Inversed emission rates of two stacks of the coal‐fired power plant for CO2 showed relatively good agreement with those estimated by a bottom‐up inventory—the Regional Emission inventory in ASia (REAS) v3.1—within −7% to 40% because the plume shapes were well identified due to constraint by NO2 measurements. The estimated NOx emission rates showed discrepancies more than 80% with those estimated by the REAS v3.1, mainly due to the uncertainties in activity data and emission factors, or in the greatly varying NO/NO2 ratios in fresh plumes, which warrant further investigations when estimating NOx emissions from satellite NO2 observations on km‐scales. Plain Language Summary: Burning of fossil fuels at high temperatures constitutes a major anthropogenic source of nitrogen oxides (NOx) and carbon dioxide (CO2). While CO2 stays in the atmosphere for hundreds of years, thereby being a well‐mixed gas, NO2 has a much shorter lifetime of only a few hours. This substantial difference in lifetime between NO2 and CO2 means that concurrent NO2 and CO2 observations obtained by the same platform can be used to identify the locations and strength of CO2 emissions from point sources such as power plants. In February 2018, for the first time, we obtained concurrent airborne spectroscopic NO2 and CO2 observations over an urban area, to demonstrate the traceability of NO2 to CO2. The plumes of co‐emitted NO2 and CO2 were derived from measured spectra. The plumes of NO2 and CO2 co‐emitted from the stacks of power plants were well identified owing to constraint by NO2. Uncertainties of inversed emission rates were statistically derived. For CO2, the results were within 40% in agreement with a bottom‐up emission inventory known as REAS v3.1. For NOx, however, a disagreement of 80% was identified, likely due to the uncertainties of the inventory data or in the NOx partitioning in fresh plumes. Key Points: Concurrent observations of NO2 and CO2 in fresh plumes from a large single point source using airborne spectrometers were reportedColumnar enhancements of NO2 and CO2 due to power plant emissions were up to 3.8 × 1016 molec.cm−2 and 75 ppm, respectivelyPlume shapes of CO2 emitted from power plants were well identified and constrained by NO2 plume shapes [ABSTRACT FROM AUTHOR]

Existing optimal control systems for vehicles that consider the effect of road slopes use a cost function with fixed weights related to speed deviation, regardless of driving states on slopes. As a result, gravitational potential energy is not efficiently exploited and braking at down-slopes (which wastes energy) becomes unavoidable. Thus, there is still significant scope to improve fuel saving behavior on slopes. To address this opportunity, in this paper, we present a dynamic eco-driving system (EDS) for a (host) vehicle based on model predictive control (MPC) with fuzzy-tuned weights, which helps efficiently utilize the gravitational potential energy. In the proposed EDS, we formulate a nonlinear optimization problem with an appropriate prediction horizon and an objective function based on the factors affecting vehicle fuel consumption. The objective function's weight is tuned via fuzzy inference techniques using information of the vehicle's instantaneous velocity and the road slope angle. By considering the vehicle longitudinal dynamics, preceding vehicle's state, and road slope information (obtained from the digital road map), the optimization generates velocity trajectories for the host vehicle that minimizes fuel consumption and CO 2 emission. We also investigate the traffic flow performance of following vehicles (behind the host vehicle) in dense traffic; this was not considered in existing works on hilly roads. The effectiveness of the proposed EDS is evaluated using microscopic traffic simulations on a real road stretch in Fukuoka City, Japan, and the results demonstrate that the fuzzy-tuned MPC EDS significantly reduces fuel consumption and CO 2 emission of the host vehicle compared to the traditional driving (human-based) system (TDS) for the same travel time. In dense traffic, the fuel consumption and CO 2 emission of following vehicles are noticeably reduced. • A fast fuzzy-tuned MPC framework is developed for eco-driving on hilly roads. • A dynamically tunable cost function is introduced to optimize the use of gravity. • The framework is tested in dense traffic using data of a road in Fukuoka, Japan. • The controlled and following cars show improved fuel consumption and CO 2 emission. [ABSTRACT FROM AUTHOR]