A quantitative comparison and analysis on the assessment indicators of greenhouse gases emission

Anthropogenic greenhouse gases （GHG） emission and related global warming issues have been the focus of international communities for some time. The international communities have reached a consensus to reduce anthropogenic GHG emissions and restrain global warming. The quantitative assessment of anthropogenic GHG emissions is the scientific basis to find out the status of global GHG emission, identify the commitments of each country, and arrange the international efforts of GHG emission reduction. Currently the main assessment indicators for GHG emission include national indicator, per capita indicator, per GDP indicator, and international trade indicator etc. The introduction to the above indi- cators is put forward and their merits and demerits are analyzed. Based on the GHG emission data from the World Resource Institute （WRI）, the US Energy Information Administration （EIA）, and the Carbon Dioxide Information Analysis Center （CDIAC）, the results of each indictor are calculated for the world, for the eight G8 industrialized countries （USA, UK, Canada, Japan, Germany, France, Italy and Russia）, and the five major developing countries including China, Brazil, India, South Africa and Mexico. The paper points out that all these indicators have some limitations. The Indicator of Industrialized Accumulative Emission per Capita （IAEC） is put forward as the equitable indicator to evaluate the industrialized historical accumulative emission per capita of every country. IAEC indicator can reflect the economic achievement of GHG emission enjoyed by the current generations in every country and their commitments. The analysis of IAEC indicates that the historical accumulative emission per capita in indus- trialized countries such as UK and USA were typically higher than those of the world average and the developing countries. Emission indicator per capita per GDP, consumptive emission indicator and survival emission indicator are also put forward and discussed in the paper.

Air pollutants and greenhouse gases emission inventory for power plants in the Antarctic

Emissions of air pollutants and greenhouse gases into the atmosphere in Antarctica from power plants with diesel generators(the main sources of energy at Antarctic research stations and the main stationary sources of anthropogenic emissions in the Antarctic)were assessed.A bottom-up approach was used to compile an emission inventory for the Antarctic.This involved estimating emissions at various spatial levels by sequentially aggregating estimate emissions from point emission sources.This is the first time this approach has been proposed and used.Emissions of CO2,NOx,particulate matter(PM10),and CO in the modern period were estimated at the research station,geographic region,natural domain,biogeographic region,continent section,and whole continent scales.Yearly emissions are presented here,but the approach allows emissions at different averaging periods to be estimated.This means mean or maximum yearly,monthly,daily,or hourly emissions can be estimated.The estimates could be used to model pollutant transmission and dispersion,assess the impacts of pollutants,and develop emission forecasts for various scenarios.

Emissions of Biogenic Sulfur Gases(H2S,COS)from Phragmites australis Coastal Marsh in the Yellow River Estuary of China

Emissions of biogenic sulfur gases(hydrogen sulfide(H_2S) and carbonyl sulfide(COS)) from Phragmites australis coastal marsh in the Yellow River estuary of China were determined during April to December in 2014 using static chamber-gas chromatography technique with monthly sampling. The results showed that the fluxes of H_2S and COS both had distinct seasonal and diurnal variations. The H_2S fluxes ranged from 0.09 μg/(m^2·h) to 7.65 μg/(m^2·h), and the COS fluxes ranged from –1.10 μg/(m^2·h) to 3.32 μg/(m^2·h). The mean fluxes of H_2S and COS from the P. australis coastal marsh were 2.28 μg/(m^2·h), and 1.05 μg/(m^2·h), respectively. The P. australis coastal marsh was the emission source of both H_2S and COS over the whole year. Fluxes of H_2S and COS were both higher in plant growing season than in the non-growing season. Temperature had a dramatic effect on the H_2S emission flux, while the correlations between COS flux and the environmental factors were not found during sampling periods. More in-depth and comprehensive research on other related factors, such as vegetation, sediment substrates, and tidal action is needed to discover and further understand the key factors and the release mechanism of sulfur gases.

The Emission Reduction Potential of Non-CO_2 Greenhouse Gases in China and Its Policy Implications

Using the improved Energy-Environmental Version of the GTAP Model (GTAP-E) and the sixth version of emission database of non-CO2 greenhouse gases, we simulate the emission reduction potential of non-CO2 greenhouse gases in China and its policy implications. The results show that at present, China is a country with the greatest emission of non-CO2 greenhouse gases in the world, and the emission will account for about 20% of the world's total emission in 2020. The proportion of emission of non-CO2 greenhouse gases from the agricultural sector reaches 73%. In the next 10 years, the emission of non-CO2 gases from cattle and sheep, industry and service industry will experience the highest growth rate; the growth rate of emission from service industry will be higher than that of emission from industry, and the emission from service industry will exceed that from industry after 2010. China can implement emission reduction policy of non-CO2 greenhouse gases to ease the international pressure of CO2 emission reduction. Although the high carbon tax collected can reduce considerable non-CO2 emission, there is little difference in policy efficiency between high carbon tax and low carbon tax. So, in the implementation of emission reduction carbon tax policy of non-CO2 gases, it is necessary to control the carbon tax at a low level.

A study of emissions and marker gases from smouldering combustion in Larix gmelinii plantations of the Daxing'an Mountains

Underground fires are characterized by smouldering combustion with a slow rate of spread rate and without flames.Although smouldering combustion releases large amounts of gaseous pollutants,it is difficult to discover by today's forest fire monitoring technologies.Carbon monoxide(CO),nitrogen oxides(NO_(x))and sulfur dioxide(SO_(2))were identified as high concentration marker gases of smouldering combustion-easily-be monitored.According to a two-way ANOVA,combustion time had a significant impact on CO and NO_(x) emissions;smoldering-depth also had a significant impact on NO_(x) emissions but not on CO emissions.Gas emission equations were established by multiple linear regression,C_(co)=156.989-16.626 t and C_(NOx)=3.637-0.252 t-0.039 h.

Quick Measurement of CH_4, CO_2 and N_2O Emissions from a Short-Plant Ecosystem

Combining improved injector, gas line and valve-driving models, a gas chromatograph (GC) equipped with Hydrogen Flame Ionization Detector (FID) and Electron Capture Detector (ECD), can measure CH4, CO2, and N2O simultaneously in an air sample in four minutes. Test results show that the system has high sensitivity, resolution, and precision; the linear response range of the system meets the requirement of flux measurements in situ. The system is suitable for monitoring fluxes of the main greenhouse gases in a short-plant field since it is easy to use, efficacious, and constant and reliable in collecting data.

Mitigation Options for Methane, Nitrous Oxide and NitricOxide Emissions from Agricultural Ecosystems

An experimental study on mitigation of greenhouse gas (CH4, N2O and NO) emission has been conducted in a typical cropping system of Southeast China for 4 years. By simultaneous measurement, the CH4, N2O and NO emission fluxes from rice-wheat rotation fields, effects of fertilization, water management, temperature and soil moisture were investigated. Temperature, fertilization and water status were found to be the key factors to regulate CH4, N2O and NO emis-sions. Based on the experimental results, some agricultural measures were recommended as techni-cal options to mitigate greenhouse gas emissions from rice-wheat rotation ecosystems. These miti-gation measures are reducing mineral N input, coupling organic manure with chemical fertilizers, applying fertilizers which release available N slowly during periods with intensive plant activity, and applying dry fermented organic manure and well management of water and fertilizer. Key words Mitigation options - Emission - Greenhouse gases - Ecosystems This study was supported by projects “ Experimental and Modeling Study on N2O Emission from the Rice-Wheat Rotation Fields of Southeast China” and “ Experimental and Modeling Study on NO Emission from Croplands” , which were granted by the National Natural Science Foundation of China, the State Key Fundamental Research Project “ Predicting the Future (20–50 years) Trend of Environmental Change in China”, and the project of Chinese Academy of Sciences “ Theory and Methodology on Air Pollution Prediction”.Thanks are due to Professor Zhang Wen, Dr. Bai Jianhui, Mr. Gong Yanbang, Mrs. Luo Dongmei and Mr. Liu Guangren from the Institute of Atmospheric Physics, Chinese Academy of Sciences for their help in experiments.

Contributions of natural systems and human activity to greenhouse gas emissions

In this study, we conducted a literature review of relevant research and then statistically analyzed global greenhouse gas (GHG) emissions from natural systems, including forest fires, oceans, wetlands, permafrost, mud volcanoes, volcanoes, and earthquakes. Drawing on the Global Carbon Project (GCP) report, we also summarized the global anthropogenic GHG emissions. We then compared the global annual GHG emissions from natural systems with those generated by human activity. The results indicate that the global annual GHG emissions range approximately between 54.33 and 75.50 Gt CO2-eq, of which natural emissions account for 18.13e39.30 Gt CO2-eq, with the most likely value being approximately 29.07 Gt CO2-eq. According to the GCP report, the global anthropogenic emissions have increased from 22 Gt CO2-eq in 1990 to 36.2 Gt CO2-eq in 2016. The amounts of natural and anthropogenic GHGs emissions are roughly of the same order of magnitude. Anthropogenic emissions account for approximately 55.46% of the total global GHGs emissions (2016 value), i.e., the ratio of natural to anthropogenic emissions is approximately 0.8. In addition, the annual amount of GHGs absorbed by Earth systems (ocean and terrestrial ecosystems) ranges between approximately 14.4 Gt CO2-eq and 26.5 Gt CO2-eq, with natural system GHG emissions and sinks also having roughly the same order of magnitude. This finding indicates that the GHG emissions generated by human activity exert extra pressure on what is otherwise a self-balancing Earth system.

Modeling Methane Emission from Rice Paddy Soils:Ⅰ.Model Development

With an understanding of the processes of methane production, oxidation and emission, a semi-empirical model, focused on the contributions of rice plants to the processes and also the influence of environmental factors, was developed to predict methane emission from rice paddy soils. In the present model, the amount of methane transported from the soil to the atmosphere was determined by the rates of CH4 production and an emitted fraction. The rates of CH4 production in irrigated rice soils were computed from the availability of methanogenic substrates that are primarily derived from rice plaaes and added organic matter and the influence of soil texture, soil redox potential and temperature. The fraction of methane emitted was assumed to be modulated by the rice plants and declines with rice growth and development. TO make it applicable to a wider area with limited data sets, a simplified version of the model was also derived to predict methane emission in a more practical manner.

Reducing Carbon Emissions Resulting from Livestock Production Using Ruminants: A Review

Greenhouse gas emissions are increas- ing every year and their effect on the environment is becoming increasingly serious. In 2009, the concen- tration of carbon dioxide in the earth＇s atmosphere reached 387 μL/L, the highest level in recorded histo- ry. This paper summarizes the global carbon emission situation, sources of greenhouse gases, and the con-tribution of agriculture to the accumutauon ot green- house gases. Several scientific measures are proposed to reduce greenhouse gas emissions resulting from ru- minant production such as improving animal perform- ance, regulating the rumen environment, and reduc- ing the amount of greenhouse gases emitted from live- stock manure.

Thermal efficiency of the principal greenhouse gases

Atmospheric gases are ranked according to the efficiency with which they absorb and radiate longwave radiation. The open international HITRAN database of gaseous absorption lines of high resolution together with inverse Fourier transform were used. The autocorrelation functions of the total dipole moment of the basic greenhouse gases molecules such as H2 O,CO2, O3, N2 O, and CH4 were obtained. Absorption coefficient spectra and emission power spectra of infrared radiation of these gases were calculated. Analysis of the emissive ability of all gases under consideration was carried out. Compared to CO2, all the gases under investigation have more effective emission except ozone. An efficiency criterion of IR absorption and emission is defined and is calculated for each studied gas, and the gases are ranked accordingly as follows（from strong to weak）： H2 O, CH4, CO2, N2 O, and O3.

Emergent Macrophytes Alter the Sediment Composition in a Small, Shallow Subtropical Lake: Implications for Methane Emission

Aquatic macrophytes in shallow lakes emit high levels of methane. We hypothesize that the presence of emergent aquatic macrophytes in an artificial shallow lake promotes important input of autochthonous organic matter (OM) in sediment and higher levels of methane emission via bubbles. Samplings were performed at three sites in a small, shallow subtropical lake: (1) one station in the limnetic region and (2) - (3) two stations in the littoral region ((2) inside and (3) outside aquatic macrophyte stands). A higher concentration of OM was observed at the macrophyte station, and within this site, a higher methane concentration was observed in the sediment. These results could explain the methane ebullition values at macrophyte sites. At the macrophyte station, methane emission via bubbles contributed 17% to 56% of the total methane emission;however, at the other stations, its contribution via bubbles, was lower than 1%. This research confirmed the importance of emergent macrophytes at Polegar Lake as a source of OM in sediment and methane emission via bubbles. Further, we could confirm the positive effects of temperature on methane emission, mainly by bubbles.

The relationship between fire severity and burning efficiency for estimating wildfire emissions in Mediterranean forests

Forests are exposed to changing climatic conditions reflected by increasing drought and heat waves that increase the risk of wildfire ignition and spread.Climatic variables such as rain and wind as well as vegetation structure,land configuration and forest management practices are all factors that determine the burning potential of wildfires.The assessment of emissions released by vegetation combustion is essential for determining greenhouse gases and air pollutants.The estimation of wildfire-related emissions depends on factors such as the type and fraction of fuel(i.e.,live biomass,ground litter,dead wood)consumed by the fire in a given area,termed the burning efficiency.Most approaches estimate live burning efficiency from optical remote sensing data.This study used a data-driven method to estimate live burning efficiency in a Mediterranean area.Burning severity estimations from Lands at imagery(dNBR),which relate to fuel consumption,and quantitative field data from three national forest inventory data were combined to establish the relationship between burning severity and live burning efficiency.Several proxies explored these relationships based on dNBR interval classes,as well as regres sion models.The correlation results between live burning efficiency and dNBR for conifers(R=0.63)and broad-leaved vegetation(R=0.95)indicated ways for improving emissions estimations.Median estimations by severity class(low,moderate-low,moderate-high,and high)are provided for conifers(0.44-0.81)and broad-leaves(0.64-0.86),and regression models for the live fraction of the tree canopy susceptible to burning(<2 cm,2-7 cm,>7 branches,and leaves).The live burning efficiency values by severity class were higher than previous studies.

Fire-induced carbon emissions from tropical mixed broad-leaved forests of the Terai–Siwalik region,central Nepal

Forest fires are one of the major environmental issues globally.In Nepal,substantial amounts of forest biomass and carbon are lost due to fire.Nepal’s high value lowland forests are particularly vulnerable to fire.However,there are limited studies on the estimation of biomass loss and carbon emissions due to fire.Thus,this research addresses the information gap in the tropical mixed broad-leaved forests of Nawalparasi District.The forests were divided into three strata:Lower Tropical Sal Mixed Broad-leaved Forest,Hill Sal Forest and Riverine Forest,and from these four community-managed forests were selected for estimating above ground biomass.Ninety-two sample plots were set out for above ground biomass estimation in burnt and non-burnt areas.Forest fire incidences from 2001 to 2017 were acquired from the MODIS fire data.Forest biomass and carbon emissions were estimated using standard allometric equations.The fuel fraction consumed during the fire was estimated through field surveys during the forest fire season.The results show that every year,over 3158 ha of forests are burnt,resulting in some 1108 tons of carbon emissions,equivalent to approximately 4066 t CO_(2),2581 t CO and 1474 t CH4.Among the forests,the Hill Sal Forest was more vulnerable to fire.Forest management strategies,therefore,should include construction of fire lines and conservation ponds along with capacity building and raising awareness among local communities and stakeholders.

Life-Cycle Analysis of Bio-Ethanol Fuel Emissions of Transportation Vehicles in Greater Houston Area

Study is conducted on the life cycle assessment of bio-ethanol used for transportation vehicles and their emissions. The emissions that are analyzed include greenhouse gases, volatile organic compounds, sulfur oxide, carbon monoxide, nitrous oxide, particulate matter with the size less than 10 and 2.5 microns. Furthermore, various blends of bio-ethanol and gasoline are studied to learn about the impacts of higher blend on emissions. The Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model software are used to simulate for emissions. The research analyzes two pathways of emissions: Well-to-Pump and Pump-to-Vehicle analyses. It is found that the fuel cell vehicles using 100% bio-ethanol have shown the most reduction in the amount of all the pollutants from the Pump-to-Vehicle emission analysis. The Well-to-Pump analysis shows that only greenhouse gases (GHGs) reduce with higher blends of bio-ethanol. All other pollutants VOC, CO, NOx, SOx, PM10 and PM2.5 emissions increase with the higher blending ratios. The Pump-to-Vehicle analysis shows that all the pollutant emissions reduce with the percentage increase of bio-ethanol in the fuel blends.

COMPARATIVE STUDY OF GREENHOUSE GAS EMISSIONS FROM HAND TUNNELING AND PILOT TUBE METHOD UNDERGROUND CONSTRUCTION METHODS

The negative effects of greenhouse gas(GHG)emissions,such as climate change and global warming,have become major environmental concerns,especially for the construction industry,which is the third-highest source of GHG emissions among industrialized countries.Presently,underground utility projects are considered one of the most common types of construction,primarily due to aging infrastructure across North America and the subsequent rehabilitation of old pipelines and installation of new pipelines and facilities.Given the increasing demand being placed on the industry,the need to study airborne emissions associated with different underground construction technologies has risen,which will be helpful in selecting the most sus-tainable underground construction methods.This study investigates pollutant emis-sion from two common trenchless methods used in underground construction,hand tunneling and pilot-tube method(PTM),through their varying GHG footprint sources and emissions measured by the United States Environmental Protection Agency(EPA).This paper analyzes a case from Edmonton,Canada,in which both PTM and hand tunneling were used by comparing the suggested indexes,including HC,CO,NO_(3) PM,CO_(2),and SO_(2).In this case study,both methods were used in the installation of a new 68-cm diameter(27 in.)clay sewer line with an overbur-den depth of 12.9 m(42 ft)and length of 60 m(197 ft).Results indicated that the amount of airborne emissions was reduced between 17%and 36%through the use of PTM compared to the traditional hand tunnelling method.

Terahertz emission in tenuous gases irradiated by ultrashort laser pulses

Mechanism of terahertz (THz) pulse generation in gases irradiated by ultrashort laser pulses is investigated theoretically. Quasi-static transverse currents produced by laser field ionization of gases and the longitudinal modulation in formed plasmas are responsible for the THz emission at the electron plasma frequency, as demonstrated by particle-in-cell simulations including field ionization. The THz field amplitude scaling with the laser amplitude within a large range is also discussed.

水力发电生命周期评价及碳足迹区域化分析

基于生命周期评价方法,对我国典型水电站水力发电生命周期碳足迹及其他环境影响进行了评估,并分析讨论了不同区域水力发电碳足迹的差异性及原因。结果显示,三峡水电站单位水电碳足迹(以CO_(2)当量计)为12.7 g/(kW·h),主要来源于运行阶段,造成其他环境影响的主要阶段为土建工程阶段,其次为机电设备制造阶段;我国不同省级行政区单位水电碳足迹差距较大,与全国平均值相差±20%以上的省级行政区有24个;各省级行政区运行阶段碳足迹占比为47.94%~96.82%,占比超过80%的省级行政区有19个。研究结果可以为我国及省级发电清单编制与电网结构调整提供数据支撑。

牛舍各种温室气体减排控制研究

温室气体指能够吸收地球大气层中长波辐射并导致大气温度升高的气体,其中二氧化碳、甲烷、氧化亚氮和氟气等是对气候变化影响最为突出的气体。畜牧业产生的温室气体排放量占全球排放总量的比例较大,因此,为减少畜牧业对气候变化的影响,控制牛舍的温室气体排放尤为重要。目前,控制牛舍温室气体排放的主要途径有两种方法:通过改善畜牧业生产方式和管理模式以减少温室气体产生;通过技术手段控制温室气体的排放。文章阐释了牛排出的温室气体在舍内的毒性作用,着重分析了影响温室气体排放的相关因素及其控制方法,从饲料成分及添加剂调控、舍内环境安置吸附剂、舍外环境优化等角度出发探讨了多种牛舍温室气体减排控制措施,剖析现有技术的优势与存在的问题,为推动环境友好型、可持续发展的科学畜禽养殖实践提供参考。

上海市典型城镇污水处理厂温室气体排放特征研究

以上海市2家典型城镇污水处理厂Ⅰ和Ⅱ为例,核算近年来因直接排放和间接排放产生的碳排放量。污水厂Ⅰ和Ⅱ的碳排放主要来自于对N污染物的处理,分别占总碳排放的61.36%、46.18%;污水厂Ⅰ电耗产生的碳排放从2015年到2022年翻了一番,污水厂Ⅱ电耗产生的碳排放占比达45.20%。2家污水厂单位进水的总排放强度分别为1065.02、1110.26 g CO_(2)eq/m^(3),与国内某些厂相比属较高水平;与IPCC缔约国相比,2座厂人均碳排放强度分别为1.76、1.93 kg CO_(2)eq/人,属较高水平。此研究运用指南进行核算,有助于了解上海污水厂碳排放基本情况,进而细化核算方法、完善排放因子,是减污降碳、实施双控的基础工作。