Repositioning fertilizer manufacturing subsidies for improving food security and reducing greenhouse gas emissions in China

China removed fertilizer manufacturing subsidies from 2015 to 2018 to bolster market-oriented reforms and foster environmentally sustainable practices.However,the impact of this policy reform on food security and the environment remains inadequately evaluated.Moreover,although green and low-carbon technologies offer environmental advantages,their widespread adoption is hindered by prohibitively high costs.This study analyzes the impact of removing fertilizer manufacturing subsidies and explores the potential feasibility of redirecting fertilizer manufacturing subsidies to invest in the diffusion of these technologies.Utilizing the China Agricultural University Agri-food Systems model,we analyzed the potential for achieving mutually beneficial outcomes regarding food security and environmental sustainability.The findings indicate that removing fertilizer manufacturing subsidies has reduced greenhouse gas(GHG)emissions from agricultural activities by 3.88 million metric tons,with minimal impact on food production.Redirecting fertilizer manufacturing subsidies to invest in green and low-carbon technologies,including slow and controlled-release fertilizer,organic-inorganic compound fertilizers,and machine deep placement of fertilizer,emerges as a strategy to concurrently curtail GHG emissions,ensure food security,and secure robust economic returns.Finally,we propose a comprehensive set of government interventions,including subsidies,field guidance,and improved extension systems,to promote the widespread adoption of these technologies.

Effect of rice cultivar on greenhouse-gas emissions from rice-fish co-culture

In aquaculture,co-culturing rice with fish may mitigate greenhouse-gas emissions.In this study,co-culture of four rice cultivars in a laboratory-scale rice–fish system reduced CH_(4)and N_(2)O emissions relative to fish monoculture.Differences in CH_(4)and N_(2)O emissions among rice cultivars primarily stem from the differential effects of rice plants on plant-mediated CH_(4)transport,CH_(4)oxidation and nitrogen absorption.

Greenhouse gas emissions from a constructed wetland for municipal sewage treatment

The fluxes of greenhouse gases (methane and nitrous oxide) emission from a constructed wetland in the Eastern China as municipal sewage treatment were measured from June 1999 to August 2000 by the closed chamber method. The constructed wetland for municipal sewage treatment is a significant source of methane, up to 976 6×10 6 g CH 4/a, which was emitted from the constructed wetland with the area of 495000 m 2 and wastewater loading rate of 12000 m 3/d. Its daily mean methane flux reached 5 22 g CH 4/(m 2·d), 250 times as much as that in natural wetland in the same latitude region. 227 8 mg CH 4 was produced from the treatment of 1 liter wastewater, up to 700—1000 times as much as that in the secondary treatment. The emission of nitrous oxide from the constructed wetland is not higher than that from secondary treatment of wastewater, only 0 07 mgN 2O/L.

Greenhouse gas emissions from shallow uncovered coal seams

This study discusses a method of quantifying emissions from surface coal mining that has been trialled in Australia. The method is based on direct measurement of surface emissions from uncovered coal seams in mine pits, concurrent measurement of residual gas content of blasted coal in mine pits, and measurement of pre-mining gas content of the same seam from cores retrieved from exploration boreholes drilled away from active mining. The results from one of the mines studied are presented in this paper. In this mine,the pre-mining gas content of the target seam was measured using cores from an exploration borehole away from active mining. Gas content varied from 0.7 to 0.8 m3/t and gas composition varied from16% to 21% CH4(84–79% CO2). In-pit measurements included seam surface emissions and residual gas content of blasted and ripped coal. Residual gas content varied from 0.09 to 0.15 m3/t, less than twofold across the mine pit. Composition of the residual gas was in general 90% CO2and 10% CH4, with slight variation between samples. Coal seam surface emissions varied from 1.03 to 7.50 mL of CO2-e per minute and per square meter of the coal seam surface, a sevenfold variation across the mine pit.

Scenario analysis on abating industrial process greenhouse gas emissions from adipic acid production in China

Adipic acid is an important petrochemical product,and its production process emits a high concentration of greenhouse gas N_2 O.This paper aims to provide quantitative references for relevant authorities to formulate greenhouse gas control roadmaps.The forecasting method of this paper is consistent with the published national inventory in terms of caliber.Based on the N_2 O abatement technical parameters of adipic acid and the production trend,this paper combines the scenario analysis and provides a measurement of comprehensive N_2 O abatement effect of the entire industry in China.Four future scenarios are assumed.The baseline scenario(BAUS) is a frozen scenario.Three emission abatement scenarios(ANAS,SNAS,and ENAS) are assumed under different strength of abatement driving parameters.The results show that China's adipic acid production process can achieve increasingly significant N_2 O emission abatement effects.Compared to the baseline scenario,by 2030,the N_2 O emission abatements of the three emission abatement scenarios can reach 207-399 kt and the emission abatement ratios can reach 32.5%-62.6%.By 2050,the N_2 O emission abatements for the three emission abatement scenarios can reach 387-540 kt and the emission abatement ratios can reach 71.4%-99.6%.

Development of National Greenhouse Gas Emissions Inventories in the Context of International Climate Negotiations

Based on the principle of common but differentiated responsibilities, the UNFCCC has different requirements on national GHG inventories submitted by Annex I and non-Annex I parties. Since 2007, the transparency of mitigation actions by developing countries, the submission frequency of national communications cored on national inventory and the relevant international consultation and analysis have become the key issues in climate negotiations. Relevant responsibilities of developing countries showed an increasing trend. Through the analysis of these different requirements, particularly on technical review system of national inventories on developed countries and of the current situation of China's inventory development, the challenges faced by China are identified and the corresponding countermeasures are also put forward, including improving institutional arrangements and statistic system, building country-specific and comprehensive database and preparing for time-series inventory development.

Effects of Biochar Application on Soil Properties, Plant Biomass Production, and Soil Greenhouse Gas Emissions: A Mini-Review

Biochar has been applied extensively as a soil amendment over the past decades. This review summarizes the general findings of the impacts of biochar application on different aspects from soil physical, chemical, and microbial properties, to soil nutrient availabilities, plant growth, biomass production and yield, greenhouse gases (GHG) emissions, and soil carbon sequestration. Due to different biochar pyrolysis conditions, feedstock types, biochar application rates and methods, and potential interactions with other factors such as plant species and soil nutrient conditions, results from those studies are not inclusive. However, most studies reported positive effects of biochar application on soil physical and chemical properties, soil microbial activities, plant biomass and yield, and potential reductions of soil GHG emissions. A framework of biochar impacts is summarized, and possible mechanisms are discussed. Further research of biochar application in agriculture is called to verify the proposed mechanisms involved in biochar-soil-microbial-plant interactions for soil carbon sequestration and crop biomass and yield improvements.

Analysis of Solid Waste Management and Greenhouse Gas Emissions in México: A Study Case in the Central Region

In this work, an analysis of the generation, composition and management of the urban solid waste in Mexico and its relation to greenhouse gas emissions is described;as well a case study in Morelos, a state in the central region of the country. Data were collected from the scientific literature and existing data bases at state and national levels. In addition, the emissions of greenhouse gas were calculated for a period of 14 years, using the Intergovernmental Panel on Climate Change (IPCC) methodology. The municipal solid waste data collected from 1998 to 2012 reveal an increase in the amount of waste generated in Mexico and in Morelos (38% and 43%, respectively), which have been influenced by the urbanization process and the population increase. According to the official data, the composition of the urban solid waste in Mexico, is mostly organic matter (50%), represented by food and garden residues, as well as paper and cardboard (near to 14%). While in Morelos, the percentages of generation for these materials are 44% and 9%, respectively. The management of the urban waste mainly consists of house collection, principally in metropolitan zones and medium and small cities, representing 78.7% in Mexico and 89.2% in Morelos. The second way to eliminate the solid wastes is open burning (mostly in semi-urban and rural areas), representing 14.5% and 6.7% for Mexico and Morelos, respectively. During this period, the nationwide greenhouse gas emissions derived from solid waste management (SWM) increased by 180%, while in Morelos, an increase of 42.5% was calculated. Thus, the population increment and urbanization process were correlated with the rise in the amount of residues generated in Mexico and Morelos.

Optimal scenario balance of reduction in costs and greenhouse gas emissions for municipal solid waste management

To reduce carbon intensity, an improved management method balancing the reduction in costs and greenhouse gas(GHG)emissions is required for Tianjin's waste management system. Firstly, six objective functions, namely, cost minimization, GHG minimization, eco-efficiency minimization, cost maximization, GHG maximization and eco-efficiency maximization, are built and subjected to the same constraints with each objective function corresponding to one scenario. Secondly, GHG emissions and costs are derived from the waste flow of each scenario. Thirdly, the range of GHG emissions and costs of other potential scenarios are obtained and plotted through adjusting waste flow with infinitely possible step sizes according to the correlation among the above six scenarios. And the optimal scenario is determined based on this range. The results suggest the following conclusions. 1) The scenarios located on the border between scenario cost minimization and GHG minimization create an optimum curve, and scenario GHG minimization has the smallest eco-efficiency on the curve; 2) Simple pursuit of eco-efficiency minimization using fractional programming may be unreasonable; 3) Balancing GHG emissions from incineration and landfills benefits Tianjin's waste management system as it reduces GHG emissions and costs.

Estimation of greenhouse gas emissions in China and the abatement measures

The major emission sources of carbon dioxide, methane, nitrous oxide and CFCs in China have been identified, and the emission trends has been estimated. Besides fossil fuel combustion, human respiration and biomass burning are important sources. Some feasible abatement measures on energy conservation, afforestation and biomass recycling have been discussed.

Energy return on investment, energy payback time, and greenhouse gas emissions of coal seam gas(CSG) production in China: a case of the Fanzhuang CSG project

The studies and development of coal seam gas（CSG） have been conducted for more than 30 years in China, but few of China＇s CSG projects have achieved large-scale commercial success; faced with the boom of shale gas, some investors are beginning to lose patience and confidence in CSG. China currently faces the following question： Should the government continue to vigorously support the development of the CSG industry？ To provide a reference for policy makers and investors, this paper calculates the EROI_（stnd）[a standardized energy return on investment（EROI） method], EROI_（ide）（the maximum theoretical EROI）, EROI_（3,i）（EROI considering the energy investment in transport）, and EROI_（3,1＋e）（EROI with environmental inputs） of a single vertical CSG well in the Fanzhuang CSG project in the Qinshui Basin. The energy payback time（EPT） and the greenhouse gas（GHG） emissions of the CSG systems are also calculated. The results show that over a 15-year lifetime, EROI_（stnd）, EROI_（ide）, EROI_（3,1）, and EROI_（3,1＋e）are expected to deliver EROIs of approximately11：1, 20：1, 7：1, and 6：1, respectively. The EPT within different boundaries is no more than 2 years, and the life-cycle GHG emissions are approximately 18.8 million kg CO_2 equivalent. The relatively high EROI and short EPT indicate that the government should take more positive measures to promote the development of the CSG industry.

Is pork trade good for China's greenhouse gas emissions?

China produces the largest amount of pork in the world, which emits the largest amount of greenhouse gases （GHGs）. This paper calculates GHG emissions from China＇s hog production at the provincial level using newly published emission factors~ Empirical results show that GHG emissions from China＇s hog production mainly respond to the scale intensity~ Capital abundance and income contribute positively to GI-IG emissions from hog production. Pork trade increases GHG emissions from China＇s hog produc- tion with a significantly direct effect, reduces GHG emissions through indirect technique effects.

Impacts of Basic Seedling on Yield-Scaled Greenhouse Gas Emissions from Rice Fields in China

Many researches showed a comprehensive assessment of the cropping practice effect on greenhouse gas （GHG） emissions per unit yield （yield-scaled） rather than per the land area （area-scaled）, and it was noteworthy that cropping practices decided to increase or decrease grain yield, and reduce or promote greenhouse gas emissions. In this study, a meta-analysis was conducted to quantify the effects of rice basic seedlings （BS） on the global warming potential （GWP） of GHG emissions at the yield-scale in China. The results suggested that significant difference was observed in yield-scaled GWP of BS. The lowest yield-scaled GWP occurred at 80-100 BS （415.65 kg CO2 equiv/mg）. The yield-scaled GHG emission from high to low was that of the hybrid rice varieties （1 028.86 kg CO2 equiv/mg）, the conventional rice varieties （634.15 kg CO2 equiv/mg） and the super rice varieties （576.57 kg CO2 equiv/mg）. Consequently, the model of conventional rice varieties and super rice varieties at 80-100 BS could be a scientifc method of matching inthe rice cropping system. A further assessment of rice density and variety impacts on GHG emissions at yield-scale was urgently needed to develop, so as to achieve win-win policies of rice production for higher yield with lower emissions.

An Analysis of the Greenhouse Gas Emissions by the Re-Liquefaction of Boil-Off Gas of LNG Storage Tank

The pressure in liquefied natural gas (LNG) storage tank continues to increase due to the heat transfer from ambient air to low temperature LNG, which raises safety concerns. Accordingly, there is increasing interest to explore the technical approaches capable of recovering Boil-Off Gas (BOG) and even eliminating the ventilation of LNG storage tank. This research numerically analyzed the greenhouse gas emissions of the re-liquefaction of BOG using the following four approaches: 1) a Claude cycle driven by electrical motor with the electricity produced by burning coal;2) a Claude cycle driven by a gas turbine fuelled by BOG released;3) a Claude cycle driven by a SI engine fuelled by gasoline;4) burning nature gas directly released by BOG. The impact of heat transfer coefficient, LNG tank configuration, size, and percentage of LNG stored in tank on the rate of BOG and energy needed for the re-liquefaction of methane vapor were investigated. The greenhouse gas emissions (GGE) was examined and compared. The data presented in this paper provide guideline for the management of pressure development in LNG storage tank.

Effects of Nitrogen Application Rate to Late Rice on Greenhouse Gas Emissions and Soil Carbon Pool During the Growing Season of Winter Chinese Milk vetch

It is of important referential values for the further understanding of the effects of fertilization on greenhouse gas emissions and the effects of winter green manure on soil carbon pool to study the effects of fertilization on the greenhouse gas emissions and soil carbon pool during the growing season of winter Chinese milk vetch in the process of rice cultivation.This study investigated the effects of nitrogen application in late rice season on the yield of the succeeding Chinese milk vetch and greenhouse gas emissions as well as the soil carbon pool characteristics after the winter planting of Chinese milk vetch with the winter idling of no nitrogen application as the control.The results showed that the yield of Chinese milk vetch was the highest under the nitrogen application of 225 kg/hm^2 in the late rice season,reaching up to 18 388.97 kg/hm^2,which was significantly different from other treatments( P <0.05).Nitrogen application in late rice season increased the emissions of N_2 O,CH_4,CO_2 and global warming potential( GWP) in the growing season of Chinese milk vetch.Compared with the winter idling treatment,winter planting of Chinese milk vetch significantly increased the soil organic carbon and soil carbon pool management index.The yield of Chinese milk vetch was significantly positively correlated with N_2O and CH_4 emissions( P < 0.05),while it presented extremely significant positive correlations with CO_2 emissions,GWP,active organic carbon,and carbon pool management index( P < 0.01).Nitrogen application in the late rice season increased the emissions of N_2 O,CH_4,CO_2,and enhanced the greenhouse gas emission potential during the growing season of Chinese milk vetch.Therefore,without reducing the yield of rice,reducing the amount of nitrogen fertilizer in rice could reduce the greenhouse gas emissions in the growing season of succeeding Chinese milk vetch.

Qualification of Soft Costs of the US Federal Guidance When Considering Greenhouse Gas Emissions and the Effects of Climate Change in NEPA Reviews

A notice by the Council of Environmental Quality (CEQ) was published on December 14, 2014 regarding the revised “Draft Guidance for Federal Departments and Agencies on Consideration of Greenhouse Gas Emissions and the Effects of Climate Change in NEPA Reviews”. The review of this 2014 draft guidance suggested increased analysis, work, review and approvals required by the State Department of Transportation (DOT) and Federal Highway Administration (FHWA) working with and on behalf of local public agencies (LPAs) in order to authorize and obligate roadway projects funded with federal-aid money. All federal-aid-funded roadway projects require a NEPA analysis to be done on the action (project) and an environmental clearance document to be obtained prior to finalizing the design. The 2014 draft guidance may complicate an already lengthy and often critical path activity for roadway projects requiring NEPA documentation.

Quantifying Greenhouse Gas Emissions from Irrigated Rice Production Systems in Ghana

Estimation of the carbon footprint in rice cropping systems can help in identifying the major options available in the quest to reduce greenhouse gas (GHG) emissions in agricultural production. This research study assessed the greenhouse gas emissions of irrigated rice production based on field experiments and surveys. The study determined the effect of application of different nitrogen rates on crop yield, carbon footprint and net carbon in irrigated rice (Oryza sativa var KRC Baika) production systems. A three-year (one minor season followed by two major seasons) field experiment was conducted on a Vertisol in a completely randomized design with four nitrogen application rates. Biomass yield and the N content of straw and grain were determined after harvest. Additionally, data on detailed farm activities relative to the cultivation of the rice crop, input use as well as biomass yield were obtained and used to estimate the carbon footprint during the study. The results showed that between 862 and 1717 kg CO2-eq ha-1 was emitted from rice fields per season. From this study, nitrogen fertilizer with about 42% of the emissions, was the biggest contributor to total GHG emissions ha-1 of rice crop. Applying nitrogen fertilizer at 90 kg N ha-1 gave a similar yield, but with a lower carbon footprint relative to the application of 135 kg N ha-1. Therefore, applying N at 90 kg N ha-1 maintained yields, reduced GHG emissions and had a positive net carbon. The results of this study can be applied to ensure that farmers maintain yields with less cost to the environment.

The Effect of Catena Position on Greenhouse Gas Emissions from Dambo Located Termite (<i>Odontotermes transvaalensis</i>) Mounds from Central Zimbabwe

Methane (CH4), carbon dioxide (CO2) and nitrous oxide (N2)O) are greenhouse gases (GHGs) which cause global warming. Natural sources of GHGs include wetlands and termites. Previous studies have quantified GHG emissions from upland termites and no study has reported GHG emissions from seasonal wetlands (dambo) located termite mounds. The objective of this study was to evaluate the effect of dambo catena position on termite mound distribution and GHG emissions. It was hypothesized that mound density and GHG emissions from Odontotermes transvaalensis mounds, vary with catena position. The evaluated catena positions were margin, mid-slope, lower slope and bottom. Mound density was significantly lower in the bottom when compared to the other catena positions. The mean GHG fluxes were 88 μg m2 hr-1, 0.78 mg m2 hr-1 and 1361 mg m2 hr-1 for N2) O, CH4 and CO2 respectively. Fluxes varied with catena position and were 0.48, 0.72, 1.35 and 0.79 mg m-2 hr-1 for CH4 , and 1173.7, 1440.7, 1798.7 and 922.8 mg m-2 hr-1 for CO2 in the margin, mid-slope, lower slope and the bottom catena position respectively. For N2) O, there were no significant differences between catena positions. It was concluded that dambo located Odontotermes transvaalensis termite mounds are an important source of GHGs, and emissions varied with catena position for CO2 and CH4.

Decoupling of greenhouse gas emissions from economic growth in Cameroon

Knowledge of decoupling indicators and its determinants is useful for formulating targeted policy recommendations. To this end, the Log-Mean Divisia Index and Tapio models were applied in this paper to study the decoupling relationship among economic growth and GHG emissions in Cameroon over the period 1971-2014. The analyzes were conducted according to the three major periods that marked Cameroon after independence and the decoupling indicators were broken down into seven factors while considering the three main GHGs emitted in this country (i.e. CO2, CH4, and N2O). The results showed that weak decoupling, strong decoupling, and strong negative decoupling occurred in Cameroon during the periods 1971-1984 and 1994-2014 which represent the periods before and after the economic crisis, respectively. In addition to these three decoupling statuses, recessive decoupling only appeared during the economic crisis period (1984-1994). From 1971 to 1984 and between 1994 and 2014, carbon intensity, economic activity, population, and emission factor not only contributed to the increase of Cameroon’s GHG (particularly CO2) emissions but also prevented decoupling. Unlike the period 1984-1994, energy intensity contributed to reducing environmental pollution while promoting decoupling during the periods 1971-1984 and 1994-2014. Although all played an important role in decoupling, we found that after the introduction of natural gas into the country’s energy mix from 2007, the effect of renewable energies on the mitigation of Cameroon’s CO2 emissions remained higher than the substitution of fossil fuels. However, to develop a cleaner economy, Cameroon should maintain modest economic growth and continuously transform economic development pathways, while encouraging the use of renewable energy to further reduce energy intensity per unit of GDP per capita.

Greenhouse gas emission analysis and measurement for urban rail transit: A review of research progress and prospects

Rail transit plays a key role in mitigating transportation system carbon emissions.Accurate measurement of urban rail transit carbon emission can help quantify the contribution of urban rail transit towards urban transportation carbon emission reduction.Since the whole life cycle of urban rail transit carbon emission measurement involves a wide range of aspects,a systematic framework model is required for analysis.This research reviews the existing studies on carbon emission of urban rail transit.First,the characteristics of urban rail transit carbon emission were determined and the complexity of carbon emission measurement was analyzed.Then,the urban rail transit carbon emission measurement models were compared and analyzed in terms of the selection of research boundaries,the types of greenhouse gas(GHG)emissions calculation,and the accuracy of the measurement.Following that,an intelligent station was introduced to analyze the practical application of digital collaboration technology and energy-saving and carbon-reducing system platforms for rail transit.Finally,the urgent problems and future research directions at this stage were discussed.This research presents the necessity of establishing a dynamic carbon emission factor library and the important development trend of system integration of carbon emission measurement and digital system technology.