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Agriculture is a significant anthropogenic source of methane (CH4) and nitrous oxide (N2O). This review provides an overview of the emissions of the two greenhouse gases (GHGs) from agricultural fields and mitigation options based on previously published field studies mainly conducted in Japan. Rice paddy fields in Japan emitted 11,982 kt CO2eq of CH4, accounting for 43.6% of the total CH4 anthropogenic emissions in 2021. Global meta-analysis shows that mid-season drainage (MD) is more effective in reducing CH4 emissions from rice paddy fields than continuous flooding. In the regions where MD is already practiced, prolonged MD (a week longer than usual MD) has been proposed to further reduce CH4 emissions compared to conventional MD. A field survey conducted at nine sites across Japan showed that prolonging MD reduced CH4 emissions and global warming potential (CH4 + N2O) by 30% and 28%, respectively. Moreover, in Japan, the autumn incorporation of rice straw was shown to reduce annual CH4 emissions by 54% on average compared with spring incorporation. Subsurface drainage and the application of iron-containing materials have been shown to reduce CH4 emissions from paddy fields, although further field studies testing various conditions are needed. In addition to CH4 emissions from rice paddy fields, agricultural soil in Japan in 2021 emitted 5962 kt CO2eq of N2O, accounting for 28.9% of the total anthropogenic N2O emissions. Meta-analyses indicated that nitrification inhibitors and polymer-coated fertilizers were effective in reducing N2O emissions after the application of synthetic N fertilizers. Moreover, biochar application was shown to be effective in sequestering soil carbon and has also been investigated as a mitigation option to reduce CH4 and N2O emissions; however, the results were inconclusive. The Ministry of Agriculture, Forestry, and Fisheries is now promoting prolonged MD and autumn incorporation of rice straw through a direct payment program to reduce CH4 emissions from paddy fields in Japan. In addition, prolonged MD and biochar application have been approved as J-Credit methodologies to reduce CH4 emissions from paddy fields and sequester soil carbon, respectively. Further studies are warranted to develop practical mitigation strategies to reduce GHG emissions while maintaining productivity. [ABSTRACT FROM AUTHOR]

Methane (CH4) emission from tree stems (stem CH4 emission) is a previously overlooked emission pathway in forested wetlands. Despite growing evidence of its significance to both regional and global CH4 budgets, the drivers and mechanisms of stem CH4 emission in wetlands are not fully understood. To clarify the environmental drivers of stem CH4 emission, we conducted chamber-based flux measurements for mature Alnus japonica and Fraxinus mandshurica trees in a forested wetland in northern Japan over four snow-free seasons, as well as a short-term flooding experiment and an isotopic analysis of stem-emitted and soil porewater CH4. Stem CH4 fluxes varied seasonally and annually. The highest flux, exceeding 10,000 µg CH4 m−2 h−1, occurred in August 2016 following a record-breaking rainfall. Soil temperature and water-table depth had significant effects on stem CH4 flux. Artificial flooding remarkably increased stem CH4 flux more than tenfold within 4 days and elevated fluxes persisted for at least 1 day after the floodwater receded. Stem-emitted CH4 was depleted in 13C by an average of 2–3‰ relative to porewater CH4, implying isotopic fractionation of CH4 by diffusion and/or oxidation along its emission pathway. Belowground environmental conditions exhibited considerable control over stem CH4 emissions in forested wetlands; the biogeochemical and biological mechanisms of this influence should be further explored. [ABSTRACT FROM AUTHOR]

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Squid-jigging has one of the highest levels of fuel consumption and greenhouse gas emission per kg of fish production of any of Korea's fisheries. The lights on squid-jigging vessels are the primary reason for their high fuel use and account for about 65% of total fuel costs for these vessels. This suggests that a high-efficiency lighting system would improve fisher's profits and reduce environmental impact. This study analyzed the economic feasibility of changing the fishing lights on squid-jigging vessels from metal halide (MH) lights to light-emitting diodes (LED) lights in terms of managing fuel costs and decreasing greenhouse gas emissions. Net present value (NPV) and benefit-cost ratio (BCR) approaches were used including with a sensitivity analysis of a governmental subsidy of the fishery for the use of LED lights. Fuel use would be reduced by 65,163 kL (USD 54,999,302) and GHG emissions would be reduced by 172,486 tCO 2 e annually if all offshore squid-jigging vessels changed to LED lights. The annual economic benefits ranged from KRW 1034.9 million (USD 932,351) to KRW 1724.9 million (USD 1,553,919) when the minimum and maximum values for Korean carbon trading prices were applied, respectively. Furthermore, the NPV and BCR results showed that it would be economically feasible to use LED lights if a vessel operated for 10 years after changing its system. The NPV that included benefits of fuel reduction and greenhouse gas emission reduction credits was 89% (USD 22,786) higher than when considering fuel reduction alone. The benefit of Government subsidies for installing LED lights was sensitive to catch rate and was only necessary if catches fell below 78.9% of that achieved with MH lights. The subsidy rate with the NPV set to zero increased about 9.3% when the catch production ratio of squid decreased by 1%. This analysis shows there is substantial opportunity for reducing emissions in fisheries by adopting lower emission technology. Adoption can require Government intervention, such as with subsidy in this case despite long run benefits of reduced fuel use and thus cost through the adoption of LED lights. [ABSTRACT FROM AUTHOR]

To address greenhouse gas emissions from international shipping, the International Maritime Organization has adopted technical and operational measures, and discussed the possibility of adopting market-based measures. China, Japan and South Korea are major shipbuilding nations in the world, and have differing responses towards the IMO's regulatory initiatives. This paper conducts a comparative assessment of these three countries' positions on regulatory principles of the greenhouse gas issue, and concludes that their differentiated perspectives on this matter reflect their different regulatory interests. It is significant to take their differentiated interests into account in the developing regulatory regime to avoid disproportionate burdens being placed on certain countries, in particular developing countries. [ABSTRACT FROM AUTHOR]

Abstract: Coffee is an important global beverage, and has received significant attention especially in terms of the social and environmental sustainability of its production. This paper calculates the product carbon footprint (PCF) and conducts an analysis of energy usage for six alternative coffee products. The analysis shows that espresso coffee had the lowest impact (0.13 kWh and 49 g CO2 per serve), while canned coffee provided the highest impact (0.76 kWh and 223 g CO2 per serve). The latte had the second highest embodied energy impact, with 0.54 kWh and the highest PCF of 224 g CO2 per serve. On a per millilitre basis however, espresso coffee provided the highest impact (0.0048 kWh/mL and 0.8 g CO2-eq/mL), followed by canned coffee and the latte. This indicates that care must be used in the selection of an appropriate functional unit, as the ranking of PCF can be overturned according to the basis of comparison. The highest contributing factors were the emissions from milk, packaging (for the can) and the production stages of the green coffee beans. Despite only holding around 17% of the market share of consumed coffee, the canned coffee product contributes around half of the national carbon footprint from coffee consumption. Current commercial incentives for consumers to use their own cups were compared to carbon taxation and found to value carbon approximately three orders of magnitude higher than carbon market rates. [Copyright &y& Elsevier]

Here we have investigated the emission of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) from long- and short-term organic farming Andosols in Matsumoto city of Nagano, in central Japan. We focus on three upland plots in Matsumoto, distinguished by how long they had each experienced continuous organic farming (OF)—in these three cases, since 1971, 2009, and 2010 (plots hereafter termed M39-OF, M1-OF, and M1F-OF, respectively). Since 2001, in M39-OF, mainly rye (Secale cereale L., as green manure) and soybeans [Glycine max (L.) Merril, as crop] were cultivated, in winter and summer respectively, without tillage, other fertilizers and agro-chemicals. In contrast, from 2001 to 2008 in M1-OF, and from 2001 to 2009 in M1F-OF, these plots underwent conventional farming of some vegetables with tillage, fertilizer and agro-chemicals. Soils sampled from M39-OF and M1-OF in August 2009 were incubated for 4 weeks in darkness at 25°C. During these 4 weeks, M39-OF emitted 8.0 times more CO2 and 274 times more N2O than M1-OF. Less than 2 µg carbon (C) kg–1 dry soil of CH4 was emitted from both soils. From February 2010 until January 2011, CO2, CH4, and N2O emission rates of M39-OF and M1F-OF were measured almost monthly, using a closed-chamber method. Annual CO2, CH4, and N2O emissions were 317, –1.7, and 27 g CO2-C equivalent m–2 in M39-OF, and 138, –0.2, and 21 g CO2-C equivalent m–2 in M1F-OF, respectively. The rye yield in M39-OF was 334 g C m–2. Soybeans in M39-OF and M1F-OF yielded 290 and 286 g C m–2, and withdrew 230 and 224 g C m–2, respectively. Greenhouse gas (GHG) balance was calculated at –52 and 97 g CO2-C equivalent m–2 in M39-OF and M1F-OF, respectively. Negative GHG balance indicated that M39-OF was acting as a GHG sink, with higher CH4 absorption than M1F-OF. Further, this beneficial function for global warming was thought to be based on its cultivation system, which had included green manure application since 2001. The difference in gas exchange between incubation and field experiments was considered a reason for the difference in N2O emission between incubation and field experiments. [ABSTRACT FROM PUBLISHER]

Species in the Miscanthus genus have been proposed as biofuel crops that have potential to mitigate elevated atmospheric carbon dioxide (CO2) levels and nitrous oxide (N2O) and methane (CH4) emissions. Miscanthus sinensis is widespread throughout Japan and has been used for biomass production for centuries. We assessed the carbon (C) budget and N2O and CH4 emissions over the growing season for 2 years in a M. sinensis-dominated grassland that was naturally established around 1972 in Tomakomai, Hokkaido, Japan, which is near the northern limit for M. sinensis grassland establishment on Andisols. Average C budget was −0.31 Mg C ha−1, which indicates C was released from the grassland ecosystem to the atmosphere. Dominant components in the C budget appeared to be aboveground net primary production of plants (1.94-2.80 Mg C ha−1) and heterotrophic respiration (2.27-3.11 Mg C ha−1). The measurement of belowground net primary production (BNPP) of plants in the M. sinensis grassland was extremely variable, thus only an approximate value could be calculated. Mean C budget calculated with the approximated BNPP value was 1.47 and −0.23 Mg C ha−1 for 2008 and 2009, respectively. Given belowground biomass (9.46-9.86 Mg C ha−1) was 3.1-6.5 times higher than that of aboveground biomass may provide additional evidence suggesting this grassland represents a C sink. Average CH4 emissions across years of −1.34 kg C ha−1 would indicate this grassland acts as an atmospheric CH4 sink. Furthermore, average N2O emissions across years were 0.22 kg N ha−1. While the site may contribute N2O to the atmosphere, this value is lower compared with other grassland types. Global warming potential calculated with the approximated BNPP value was −5.40 and 0.95 Mg CO2 Eq ha−1 for 2008 and 2009, respectively, and indicates this grassland could contribute to mitigation of global warming. [ABSTRACT FROM AUTHOR]

To clarify the reason for the higher CH4 uptake rate in Japanese forest soils, twenty-seven sites were established for CH4 flux measurement. The first order rate constant for CH4 uptake was also determined using soil core incubation at 14 sites. The CH4 uptake rate had a seasonal fluctuation, high in summer and low in winter, and the rate correlated with soil temperature at 17 sites. The annual CH4 uptake rates ranged from 2.7 to 24.8 kg CH4 ha−1 y−1 (the average of these rates was 9.7 or 10.9 kg CH4 ha−1 y−1, depending on method of calculation), which is somewhat higher than the uptake rates reported in previous literature. The averaged CH4 uptake rate correlated closely with the CH4 oxidation rate of the topsoil (0–5 cm) in the study sites. The CH4 oxidation constant of the topsoil was explained by a multiple regression model using total pore volume of the soil, nitrate content, and C/N ratio ( p < 0.05, R2 = 0.684). This result and comparison with literature data suggest that the high CH4 uptake rate in Japanese forest soils depends on the high porosity probably due to volcanic ash parent materials. According to our review of the literature, the CH4 uptake rate in temperate forests in Europe is significantly different from that in Asia and North America. A new global CH4 uptake rate in temperate forests was estimated to be 5.4 Tg y−1 (1 SE is 1.1 Tg y−1) on a continental basis. [ABSTRACT FROM AUTHOR]

Low carbon city development and greenhouse gas (GHG) emission mitigation in urban communities are urgent. There is great potential to improve the GHG inventory at the community level. Meanwhile, building zero-waste cities and improving waste treatment efficiency have been significant environmental issues due to the rapid increase of waste generation. This research aims to develop a community-scale GHG emission inventory of the waste sector and improve its accuracy and consistency through applying the bottom-up approach. This study covers both direct and indirect emissions categories of the waste sector with the goal of building a zero-waste community. Honjo Waseda community, located in Japan, was used as a case study community. Energy consumption waste treatment sectors were evaluated and calculated through first-hand field data. GHG emission estimation of the waste sector included waste incineration, residential wastewater, and waste transport. The highest emissions originated from Beisiagate supermarket due to the large waste amount produced, and the CO2-biomass carbon emissions reached approximately 50% of the total emissions. Furthermore, a quantitative analysis of the implementation of new technologies was also conducted. This study created proposals for GHG emission reduction toward a zero-waste community through the comparison of three cases. Case 1 was business as usual; Case 2 proposed a combination of incineration bio-gasification (MBT); Case 3 introduced a combination of solid recovered fuel (SRF) and a bio-gasification system. SRF contributed the most to emission reduction, and Case 3 exhibited the highest energy recovery. Furthermore, comparing the GHG emissions produced by the use of SRF for power generation and heat supply revealed that using SRF as a heat supply reduced more GHG emissions than using SRF for power generation. [ABSTRACT FROM AUTHOR]

The scenarios for conventional puddling and no-tilling rice ( Oryza sativa L.) cultivation were compared in terms of greenhouse gas (GHG) emissions from paddy fields, fuel consumption and manufacturing of invested materials using a life cycle inventory (LCI) based analysis. Only the differences between the scenarios were examined. The no-tilling scenario omitted both tilling and puddling, but included spraying of a non-selective herbicide and used a transplanter equipped with a rotor. Fertilization was a basal single application of controlled release fertilizer in nursery boxes for all scenarios. After transplanting, there were no differences in machine work, invested materials or rice yields between the scenarios. The no-tilling scenario saved on fuel consumption, totaling carbon dioxide (CO2) output of 42 kg ha−1, which was equal to the 6% reported GHG emissions from fuel consumption by operating machines during rice production in Japan. Methane (CH4) and nitrous oxide (N2O) emissions from the paddy fields were also monitored and compared for the scenarios. Methane has a major effect on global warming as part of the GHG emitted from paddy fields. The cumulative CH4 emissions from the no-tilling cultivation were 43% lower than those from conventional puddling cultivation because the plow layer was more oxidative in no-tilling cultivation. The N2O emissions were not significantly different between the cultivation scenarios. There were no significant differences in soil respiration, soil carbon contents or straw yields between the cultivation scenarios. The effect of tillage on CO2 flux in the paddy fields did not seem to be significant in this study. Consequently, the GHG emissions from the no-tilling field counted as CO2 using global warming potentials were 1,741 kg CO2 ha−1 lower than those from the conventional puddling field. In conclusion, no-tilling rice cultivation has the potential to save 1,783 kg CO2 ha−1 calculated using the sum of fuel consumption and GHG emissions from paddy fields. No-tilling rice cultivation is considered to be environmentally friendly agriculture with respect to reducing GHG emissions. [ABSTRACT FROM AUTHOR]

Abstract: Utilization of livestock residue is important not only for energy recovery and material recycling but also for preventing environmental pollution. This paper focuses on the following options from the viewpoint of the Law on Promoting Proper Management and Use of Livestock Excreta and the Kyoto protocol: energy use from livestock residue, reductions in CO2 emissions resulting from substitution of fossil fuels, and reduction of other greenhouse gas emissions through appropriate treatment of livestock residue. Bioenergy potential of livestock residue in Japan was estimated to be 167PJ in the year 2000. This is equivalent to about 0.7% of total primary energy supply. Biogas production with methane fermentation and burning poultry residue at power plants can produce 4.1TWh of electricity and 46PJ of heat. The amount of CO2 substitution for fossil fuels is 6.9Mt-CO2. This corresponds to about 0.6% of total CO2 emissions in 1990. This also has an additional effect of reducing other greenhouse gas (CH4 and N2O) emissions from conventional treatment of livestock residue. Development of biogas plants, promotion of biogas utilization, and effective use of fertilizer components extracted from livestock residue are expected to gain importance in the future. [Copyright &y& Elsevier]

In Japan, most cows are fed indoors, so cow manure must be carefully treated and used to manage soil fertility. The objective of this study was to compare the net greenhouse gas (GHG) balance (NGHGB) of Italian ryegrass - corn (maize) double-cropping fields receiving farmyard manure (FYM), slurry, or methane fermentation digestion liquid (MFDL). FYM, Slurry, MFDL, mineral fertilizer only (Fert.), and no-N control (Cont.) plots were set up in a randomized block design (n = 3). FYM, slurry, or MFDL was applied to meet the K requirement for forage production, and then mineral fertilizers were supplemented to meet the N and P requirements. From September 2017 to September 2020, C inputs as manure and crop residue, heterotrophic respiration (R H ), and emissions of methane (CH 4 ) and nitrous oxide (N 2 O) from soil were determined. The similarity of the total yields in FYM, Slurry, MFDL, and Fert. plots reflected judicious fertility management. However, the residue-C input of Italian ryegrass was 38% greater in FYM plots than in the other plots. Manure-C input decreased in the order of FYM > Slurry > MFDL plots. R H was greater in FYM and Slurry plots than in MFDL plots. Net ecosystem C balance (NECB) ([residue-C + manure-C] - [R H -C + CH 4 -C]) decreased in the order of FYM > Slurry > MFDL plots. N 2 O emission was greater in Slurry and MFDL plots than in FYM plots. Consequently, NGHGB ([CH 4 and N 2 O emissions] - NECB) in terms of CO 2 equivalent decreased in the order of MFDL > Slurry > FYM plots, so FYM application contributed most to GHG mitigation. Yield-scaled NGHGB was smallest in FYM plots owing to the synergy of the greatest residue-C and manure-C inputs, less N 2 O emission, and the achievement of a high enough yield, reflecting judicious fertility management based on manure and mineral fertilizer., 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 © 2021 The Author. Published by Elsevier B.V. All rights reserved.)

Vehicle electrification represents a promising solution to address the challenges of energy security and sustainable mobility. The environmental performance of electric vehicles is heavily dependent on the energy structure which is undergoing a profound transition. Moreover, the deployment of electric vehicles is critically affected by policies. In this context, this study investigated the impact of energy structure transition and penetration uncertainty on emissions of electric vehicles in Japan from 2000 to 2030. The results suggested that the greenhouse gas and reactive nitrogen were mitigated for both energy sources of electricity mix transition and ammonia energy carrier compared with the baseline. Trade-off between the electricity mix transition and ammonia energy carrier scenarios was observed. Specifically, the electricity mix transition results demonstrated a more significant emission reduction of reactive nitrogen, while an ammonia energy carrier led to a more significant emission reduction of greenhouse gas. Finally, key policy implications were summarized by providing insights into energy portfolio planning and electric vehicle deployment from the perspective of climate change mitigation and sustainable reactive nitrogen management. • Modeled penetration and energy structure transition for electric vehicles. • Electricity mix transition led to more reactive nitrogen emission reduction. • Ammonia energy carrier resulted in more greenhouse gas emission reduction. • Implications were discussed providing insights into policy making. [ABSTRACT FROM AUTHOR]

Background: China and other developing countries in Asia follow similar economic growth patterns described by the flying geese (FG) model, which explains the "catching-up" process of industrialization in latecomer economies. Japan, newly industrialized economies, and China have followed this path, with similar economic development trajectories. Based on the FG model, we postulated a "flying S" hypothesis stating that if a country is located within an FG region and its energy matrix is relatively constant, its per capita CO 2 emission curve will mirror that of "leading geese" countries in the same FG group., Method: Historical CO 2 emissions data were obtained from literature review and national reports and were calculated using bottom-up methods. A sigmoid-shaped, non-linear mixed effect model was applied to examine ex post data with 1000 simulated predictions to construct 95% empirical bands from these fits. By multiplying by estimated population, we predicted total emissions of selected FG countries., Results: Per capita CO 2 emissions from the same FG group mirror each other, especially among second and third industrial sectors. We estimated an annual 18,252.24 million tons of CO 2 emissions (MtCO 2 ) (95% CI = 9458.88-23,972.88) in China and 8281.76 MtCO2 (95% CI = 2765.68-14,959.12) in India in 2030., Conclusion: This study bridges the macroeconomic FG paradigm to study climate change and proposes a "flying S" hypothesis to predict greenhouse gas emissions in East Asia. By applying our theory to empirical data, we provide an alternative framework to predict CO 2 emissions in 2030 and beyond., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

We estimated the nitrogen (N), phosphorus (P), potassium (K) and magnesium (Mg) excretion factors of broiler and layer chickens in Japan, using two approaches and the latest data available. In the top-down approach, we determined the nutrient amounts in the feeds and those in the products (i.e. the liveweight gain, eggs), and the national nutrient excretions were determined as the difference between these amounts. We then calculated the nutrient excretion factors by dividing the national excretions by the number of animals. In the bottom-up approach, we calculated the amounts of nutrients in the feed and product per head using productivity parameters (feed conversion ratio, etc.). The differences between these amounts were considered the nutrient excretion factors. The average nutrient excretion factors of broilers (g/day/head) estimated using the top-down and bottom-up approaches were: N, 1.40 and 1.87; P, 0.36, 0.50; K, 0.54, 0.77; Mg, 0.13, 0.18, respectively. The excretion factors obtained by the top-down approach can be used to calculate the national/regional excretions. The two approaches resulted in almost the same excretion factors for layers, and the average nutrient excretion factors of layers (g/day/head) estimated were: N, 2.20; P, 0.55; K, 0.68; Mg, 0.23. The estimated excretion factors for N (only) are smaller than the reported factors. [ABSTRACT FROM AUTHOR]

This paper considers synergisms between the impacts of two global processes, climate change and economic globalization. Both processes entail long-term changes that will have differential impacts throughoutthe world. Despite widespread recognition that there will be 'winners' and 'losers' with both climate change and globalization, the two issues are rarely examined together. In this paper, we introduce the concept of double exposure as a framework for examining the simultaneous impacts of climate change and globalization. Double exposure refers to the fact that certain regions, sectors, ecosystems and social groups will be confronted both by the impacts of climate change, and bythe consequences of globalization. By considering the joint impacts of the two processes, new sets of winners and losers emerge. [ABSTRACT FROM AUTHOR]