On evaluating accuracy of national methane inventories

In the last few years, nearly all industrialized countries have submitted estimates of national inventories of methane and other greenhouse gases as required under the Framework Convention on Climate Change. National inventories of methane emissions in industrialized countries are fairly complete but give some suggestion of underestimation when inventory totals are compared with recent atmospheric measurements and global budgets. In this paper, possible discrepancies are assessed for fossil fuel sources and landfills based on comparisons between independent estimates and national communications. The Kyoto Protocol to the Framework Convention and the European Union make new provisions to develop procedures for technical review of national inventories and projections, and requirements for more thorough documentation from parties, which should improve accuracy. Limits to accuracy and the political implications of underestimation are discussed in this article, along with suggestions for improving inventories through better analysis, documentation and review procedures.     

Forgotten carbon: indirect CO2 in greenhouse gas emission inventories

National governments that are Parties to the United Nations Framework Convention on Climate Change (UNFCCC) are required to submit greenhouse gas (GHG) inventories accounting for the emissions and removals occurring within their geographic territories. The Intergovernmental Panel on Climate Change (IPCC) provides inventory methodology guidance to the Parties of the UNFCCC. This methodology guidance, and national inventories based on it, omits carbon dioxide (CO₂) from the atmospheric oxidation of methane, carbon monoxide, and non-methane volatile organic compounds emissions that result from several source categories. The inclusion of this category of “indirect” CO₂ in GHG inventories increases global anthropogenic emissions (excluding land use and forestry) between 0.5 and 0.7%. However, the effect of inclusion on aggregate UNFCCC Annex I Party GHG emissions would be to reduce the growth of total emissions, from 1990 to 2004, by 0.2% points. The effect on the GHG emissions and emission trends of individual countries varies. The paper includes a methodology for calculating these emissions and discusses uncertainties. Indirect CO₂ is equally relevant for GHG inventories at other scales, such as global, regional, organizational, and facility. Similarly, project-based methodologies, such as those used under the Clean Development Mechanism, may need revising to account for indirect CO₂.     

Use of IPCC GHG key sources analysis to Mexico’s environmental policy

Intergovernmental Panel on Climate Change (IPCC) Tier 1 key sources level 1 assessment was applied to the 1994–1994 National Greenhouse Gases (GHG) emission inventory for Mexico in order to identify and analyze the key sources within it. Top key sources were from land use change and energy combustion contributing to about 60% of total national emissions. In addition, a Tier 1 trend assessment revealed some changes with respect to Tier 1 level assessment: Top key sources according to this analysis are waste disposal and delayed emissions from land clearing. Important insight for cost effective preventive mitigation actions can be extracted from this analysis. A comparison with other countries was carried out to find similarities in the GHG national emissions inventories related to common features on economic development.     

Errors and uncertainties in a gridded carbon dioxide emissions inventory

Emission inventories (EIs) are the fundamental tool to monitor compliance with greenhouse gas (GHG) emissions and emission reduction commitments. Inventory accounting guidelines provide the best practices to help EI compilers across different countries and regions make comparable, national emission estimates regardless of differences in data availability. However, there are a variety of sources of error and uncertainty that originate beyond what the inventory guidelines can define. Spatially explicit EIs, which are a key product for atmospheric modeling applications, are often developed for research purposes and there are no specific guidelines to achieve spatial emission estimates. The errors and uncertainties associated with the spatial estimates are unique to the approaches employed and are often difficult to assess. This study compares the global, high-resolution (1 km), fossil fuel, carbon dioxide (CO₂), gridded EI Open-source Data Inventory for Anthropogenic CO₂ (ODIAC) with the multi-resolution, spatially explicit bottom-up EI geoinformation technologies, spatio-temporal approaches, and full carbon account for improving the accuracy of GHG inventories (GESAPU) over the domain of Poland. By taking full advantage of the data granularity that bottom-up EI offers, this study characterized the potential biases in spatial disaggregation by emission sector (point and non-point emissions) across different scales (national, subnational/regional, and urban policy-relevant scales) and identified the root causes. While two EIs are in agreement in total and sectoral emissions (2.2% for the total emissions), the emission spatial patterns showed large differences (10~100% relative differences at 1 km) especially at the urban-rural transitioning areas (90–100%). We however found that the agreement of emissions over urban areas is surprisingly good compared with the estimates previously reported for US cities. This paper also discusses the use of spatially explicit EIs for climate mitigation applications beyond the common use in atmospheric modeling. We conclude with a discussion of current and future challenges of EIs in support of successful implementation of GHG emission monitoring and mitigation activity under the Paris Climate Agreement from the United Nations Framework Convention on Climate Change (UNFCCC) 21st Conference of the Parties (COP21). We highlight the importance of capacity building for EI development and coordinated research efforts of EI, atmospheric observations, and modeling to overcome the challenges.

     

The role of biotic carbon stocks in stabilizing greenhouse gas concentrations at safe levels

The goal of the Climate Convention and its Kyoto Protocol is to stabilize greenhouse gas concentrations in the atmosphere at a safe level. This requires both strict limits on emissions from fossil fuels and effective management of biotic carbon stocks. If fossil fuel emissions from 1990 to 2100 are limited to 600 PgC, biotic carbon stocks must increase by 120 PgC to stabilize CO₂ concentrations at 450 ppmv. Establishing an appropriate policy regime to accomplish this goal is complicated by a factor of six discrepancy between estimates of the current biotic sink based on national emissions inventories compared with global carbon cycle model calculations. Appropriate policies must also be designed to create incentives for technological innovation in the energy sector and minimize the risk of granting emission credits for biotic carbon sequestration that proves to be temporary.     

Achieving forest carbon information with higher certainty: A five-part plan

International negotiations on the inclusion of land use activities into an emissions reduction system for the UN Framework Convention on Climate Change (UNFCCC) have been partially hindered by the technical challenges of measuring, reporting, and verifying greenhouse gas (GHG) emissions and the policy issues of leakage, additionality, and permanence. This paper outlines a five-part plan for estimating forest carbon stocks and emissions with the accuracy and certainty needed to support a policy for Reducing Emissions from Deforestation and forest Degradation, forest conservation, sustainable management of forests, and enhancement of forest carbon stocks (the REDD-plus framework considered at the UNFCCC COP-15) in developing countries. The plan is aimed at UNFCCC non-Annex 1 developing countries, but the principles outlined are also applicable to developed (Annex 1) countries. The parts of the plan are: (1) Expand the number of national forest carbon Measuring, Reporting, and Verification (MRV) systems with a priority on tropical developing countries; (2) Implement continuous global forest carbon assessments through the network of national systems; (3) Achieve commitments from national space agencies for the necessary satellite data; (4) Establish agreed-on standards and independent verification processes to ensure robust reporting; and (5) Enhance coordination among international and multilateral organizations.     

Influence of Methodology and Assumptions on Reported National Carbon Flux Inventories: An Illustration from the Canadian Forest Sector

The Intergovernmental Panel on Climate Change (IPCC) has developed guidelines to standardize the international reporting of greenhouse gas emissions and removals by signatory nations of the UN Framework Convention on Climate Change. With regard to forest sector carbon fluxes, the IPCC guidelines require only that those fluxes directly associated with human activities (i.e., harvesting and land-use change) be reported. In Canada, the Carbon Budget Model of the Canadian Forest Sector (CBM-CFS2) has been used to assess carbon fluxes from the entire forest sector. This model accounts for carbon fluxes associated with both anthropogenic and natural disturbances, such as wild fires and insects. We combined model results for the period 1985 to 1989 with additional data to compile seven different national carbon flux inventories for the forest sector. These inventories incorporate different system components under a variety of seemingly plausible assumptions, some of which are encouraged refinements to the default flux inventory described in the IPCC guidelines. The resulting estimated net carbon fluxes varied from a net removal of 185,000 kt carbon per year of the inventory period to a netemission of 89,000 kt carbon per year. Following the default procedures in the IPCC guidelines, while using the best available national data, produced an inventory with a net removal of atmospheric carbon. Adding the effect of natural disturbances to that inventory reversed the sign of the net flux resulting in a substantial emission. Including the carbon fluxes associated with root biomass in the first inventory increased the magnitude of the estimated net removal. The variability of these results emphasizes the need for a systems approach in constructing a flux inventory. We argue that the choice of which fluxes to include in the inventory should be based on the importance of these fluxes to the overall carbon budget and not on the perceived ease with which flux estimates can be obtained. The results of this analysis also illustrate two specific points. Even those Canadian forests which are most free from direct human interactions—forests in which no commercial harvesting occurs—are not in equilibrium, and their contribution to national carbon fluxes should be included in the reported flux inventory. Moreover, those forest areas that are subject to direct management are still substantially impacted by natural disturbances. The critical effect of inventory methodology and assumptions on inventory results has important ramifications for efforts to “monitor” and “verify” programs aimed at mitigating global carbon emissions.     

Forest Management for Greenhouse Gas Benefits: Resolving Monitoring Issues Across Project and National Boundaries

Demand for new environmental services from forests requires improved monitoring of these services at three scales: project-, regional-, and national-level. Most forest management activities are organized at the project scale, while the Framework Convention on Climate Change (FCCC) recognizes the nation as the party to the agreement. Hence, measurement and monitoring issues are emerging at the intersections of the project and national scales, referred to here as monitoring-domain edge effects. The following actions are necessary to improve existing monitoring capabilities and to help resolve project/national edge effects: (1) consensus on standard methods and protocols for monitoring mitigation activities, their off-site greenhouse gas (GHG) impacts, the fate of forest products and their relation to national GHG inventories (baselines); (2) a global program for collecting land use, land cover, biomass burning, and other data essential for national baselines; (3) the development of new nested-monitoring-domain methods that allow projects to be identified in national GHG inventories (baselines), and permit tracking of leakage of GHGs and wood product flows outside project boundary and over time; and (4) presentation of a set of credible, carefully designed, and well-documented forest mitigation activities that resolve most of the current issues.     

Improving the quality of national greenhouse gas inventories

This paper summarises the findings of an Intergovernmental Panel on Climate Change (IPCC) Expert Meeting on Methods for the Assessment of Inventory Data Quality held in Bilthoven, The Netherlands, 5–7 November 1997. Under the Kyoto Protocol of the Climate Convention, reliable inventories of national greenhouse gases (GHG) are needed for verifying compliance. Four approaches are suggested for assessing and improving the quality of greenhouse gas inventories: inventory quality assurance; inventory comparisons; model comparisons; and direct emission measurements. The paper presents recommendations for improving the quality of emission estimates of carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O).     

Leakage of nitrous oxide emissions within the Spanish agro-food system in 1961–2009

In this paper we examine the trends of nitrous oxide (N₂O) emissions of the Spanish agricultural sector related to national production and consumption in the 1961–2009 period. The comparison between production- and consumption-based emissions at the national level provides a complete overview of the actual impact resulting from the dietary choices of a given country and allows the evaluation of potential emission leakages. On average, 1.5 % of the new reactive nitrogen that enters Spain every year is emitted as N₂O. Production- and consumption-based emissions have both significantly increased in the period studied and nowadays consumption-based emissions are 45 % higher than production-based emissions. A large proportion of the net N₂O emissions associated with imported agricultural goods comes from countries that are not committers for the United Nations Framework Convention on Climate Change Kyoto Protocol Annex I. An increase in feed consumption is the main driver of the changes observed, leading to a remarkable emission leakage in the Spanish agricultural sector. The complementary approach used here is essential to achieve an effective mitigation of Spanish greenhouse gas emissions.     

Pledges for climate mitigation: the effects of the Copenhagen accord on CO2 emissions and mitigation costs

The UN Framework Convention of Climate Change 15th Conference of the Parties Copenhagen Accord has been followed up by national pledges of greenhouse gas emissions reductions in the year 2020 without specifying measures to enforce actions. As a consequence, the capacity of parties to fulfil their obligations is of basic interest. This article outlines the effects of full compliance with pledges on greenhouse gas emissions, economic growth, and trade. The study is based on the global computable general equilibrium model global responses to anthropogenic changes in the environment (GRACE) distinguishing between fossil and non-fossil energy use. Global emissions from fossil fuels in 2020 turn out to be 15 % lower than in a business as usual scenario and 3 % below the global emissions from fossil fuels in 2005. China and India increase their emissions to 1 % and 5 % above business as usual levels in 2020. India and Russia increase their net export of steel corresponding to around 30 and 45 % of their production levels in 2020. In spite of some leakage of energy intensive production also to China, we find that structural change remains the dominant factor behind the rapid reduction of CO₂ emission intensity in China towards 2020.     

城市能源碳排放估算方法探究

作为目前世界上最大的碳排放国家,中国在2015年巴黎气候变化大会上做出承诺,到2030年碳排放量要达到峰值并且单位GDP排放要在2005年水平上下降60%～65%.但现阶段中国碳排放数据主要集中在省级和国家层面,城市作为碳减排措施实施的主要区域,由于基础数据缺乏,长久以来没有完整的碳排放清单.为解决这一问题,本文构建了一套城市级CO_2排放估算方法.该方法从各省能源平衡表(EBT)出发,采取从省级到市级的比例分配方法,选取最为贴近城市碳排放的指标数据,对42个地级市2012年的能源消费型碳排放情况进行估算,并与中国高分辨率碳排放数据(CHRED)进行对比,发现差异均在10%以内,验证了该方法的准确性.同时揭示了此类自上而下的估算方法所带来的区域性差异,并且进一步分析了采用不同来源的化石燃料的排放因子所可能导致的不确定性,建议之后的研究在进行中国城市碳排放核算时采取最恰当的本地化化石燃料排放因子.本文为获得在时间尺度和空间尺度上均连续的中国城市碳排放数据提供了参考方法和合理思路,也能为在城市层面制定科学的碳减排措施提供可靠的数据支撑.     

Emission inventory on company level: lessons from Russia

Developing a transparent,accurate greenhouse gas (GHG) emissionsinventory is the first step toward buildingan effective GHG management system. Todate, GHG inventories have been conductedprimarily at national levels. Theinternationally accepted inventorymethodology developed by theIntergovernmental Panel on Climate Change(IPCC) is oriented to countrywideinventories. The electricity company RAOUESR is the largest single corporateemitter of GHG in the Russian Federation. The company is responsible for about 1/3 ofRussia's CO₂ emissions; RAO's fossil fuelemissions are comparable to the fossil fuelemissions of the United Kingdom. The GHGinventory prepared by RAO is the first suchcorporate emissions inventory undertaken ina non-OECD country. In this article wepresent a detailed independent examinationof the methodology RAO applied for theinventory. We identify the most importantsources of uncertainty and we estimate theuncertainty. The main conclusion of theindependent review is that the methodologyutilized by RAO and the informationsupporting the methodology are reliable andpresent a reasonably accurate company-widepicture of RAO's CO₂ emissions. The shareof other greenhouse gases is negligiblysmall and we did not focus on this fractionof RAO's GHG emissions. As a next step, RAOmay wish to conduct more precisefacility-by-facility inventories in orderto create a robust GHG emission managementsystem.     

Earth observations for estimating greenhouse gas emissions from deforestation in developing countries

In response to the United Nations Framework Convention on Climate Change (UNFCCC) process investigating the technical issues surrounding the ability to reduce greenhouse gas (GHG) emissions from deforestation in developing countries, this paper reviews technical capabilities for monitoring deforestation and estimating emissions. Implementation of policies to reduce emissions from deforestation require effective deforestation monitoring systems that are reproducible, provide consistent results, meet standards for mapping accuracy, and can be implemented at the national level. Remotely sensed data supported by ground observations are key to effective monitoring. Capacity in developing countries for deforestation monitoring is well-advanced in a few countries and is a feasible goal in most others. Data sources exist to determine base periods in the 1990s as historical reference points. Forest degradation (e.g. from high impact logging and fragmentation) also contribute to greenhouse gas emissions but it is more technically challenging to measure than deforestation. Data on carbon stocks, which are needed to estimate emissions, cannot currently be observed directly over large areas with remote sensing. Guidelines for carbon accounting from deforestation exist and are available in approved Intergovernmental Panel on Climate Change (IPCC) reports and can be applied at national scales in the absence of forest inventory or other data. Key constraints for implementing programs to monitor greenhouse gas emissions from deforestation are international commitment of resources to increase capacity, coordination of observations to ensure pan-tropical coverage, access to free or low-cost data, and standard and consensual protocols for data interpretation and analysis.     

我国空气污染物人为源排放清单对比

空气污染物排放清单是影响数值模式结果准确性的关键因子之一. 定义不同排放清单中同一污染物排放量最大值与最小值之差与平均值的比值为差异度,对比分析了4个国内外广泛应用的人为污染源排放清单(TRACE-P、INTEX-B、REAS1.1和REAS2.0). 结果表明:INTEX-B、REAS1.1和REAS2.0清单中给出的2006—2007年我国(不包括港澳台地区数据)SO₂排放量差异度为12%,而在SO₂排放量较大的省份(如山东、河北和河南等)差异度达30%以上; NO_x和NMVOC(非甲烷挥发性有机物)的排放量差异度分别为51%和30%,在山东、江苏、浙江、北京和上海等经济较发达地区的差异度达到20%~80%. 相对于2000年的排放清单,2006—2007年排放清单各污染物的排放量增长明显,SO₂、NO_x和NMVOC的排放量在INTEX-B、REAS1.1和REAS2.0清单中的平均值分别为TRACE-P清单的1.6、1.9和1.5倍. 近年来经济的高速发展、能源消耗的增长和空气污染控制技术的应用等都会影响人为活动水平和排放因子的选取,这也是造成排放清单间存在差异的主要原因.      

Contribution of industrial and developing countries to the atmospheric CO2 concentrations: — impact of the Kyoto protocol

The UN Framework Convention on Climate Change and the Kyoto protocol made under the Convention, aim at controlling the greenhouse gas emissions and their concentrations in the atmosphere. The contributions of fossil fuel use in industrial and developing countries to the atmospheric CO₂ concentration are calculated using estimates for emission developments and a simple carbon cycle model. The contribution of the industrial countries to the CO₂ concentration increase, above the preindustrial level, is estimated to be about 50 ppm in 1990 if only the emissions from fossil fuels are considered. The contribution from developing countries is about 15 ppm. The contribution from industrial countries would increase by about 20 ppm between 1990 and 2010 if no emission reductions were assumed and by about 15 ppm in the considered rather strict reduction scenario. According to the Kyoto protocol the emissions from industrial countries should be reduced by 5.2% from the 1990 level in about 20 years. This development of the emissions would cause a concentration increase of 18 ppm. The concentration increase due to developing countries between 1990 and 2010 would be about 15 ppm. In order that the present global increase rate of CO₂ concentration 1.5 ppm/a would not be exceeded, steeper reductions than those made in Kyoto should be agreed. Increasing global emissions and slow removal of CO₂ from the atmosphere makes it difficult to reach the ultimate objective of the Climate Convention, the stabilisation of the atmospheric concentration.     

Tropical deforestation in a future international climate policy regime—lessons from the Brazilian Amazon

The possibility of adopting national targets for carbon dioxide (CO₂) emissions from tropical deforestation in a future international climate treaty has received increasing attention recently. This attention has been prompted by proposals to this end and more intensified talks on possible commitments for developing countries beyond the United Nations Framework Convention on Climate Change Kyoto Protocol. We analyze four main scientific and political challenges associated with national targets for emissions from tropical deforestation: (1) reducing the uncertainties in emission inventories, (2) preserving the environmental integrity of the treaty, (3) promoting political acceptance and participation in the regime, and (4) providing economic incentives for reduced deforestation. We draw the following conclusions. (1) Although there are large uncertainties in carbon flux from deforestation, these are in the same range as for other emissions included in the current Kyoto protocol (i.e., non-CO₂ GHGs), and they can be reduced. However, for forest degradation processes the uncertainties are larger. A large challenge lies in building competence and institutions for monitoring the full spectrum of land use changes in developing countries. (2 and 3) Setting targets for deforestation is difficult, and uncertainties in future emissions imply a risk of creating ‘tropical hot air’. However, there are proposals that may sufficiently deal with this, and these proposals may also have the advantage of making the targets more attractive, politically speaking. Moreover, we conclude that while a full carbon accounting system will likely be politically unacceptable for tropical countries, the current carbon accounting system should be broadened to include forest degradation in order to safeguard environmental integrity. (4) Doubts can be cast over the possible effect a climate regime alone will have on deforestation rates, though little thorough analysis of this issue has been made.

A Land Cover Change Monitoring Program: Strategy for an International Effort

An international system for monitoring land cover change is needed to support a range of scientific and policy objectives. Although much of the technology and methods are readily available, such a program has yet to be implemented. This paper outlines the rationale, requirements, and strategy for implementing a land cover-monitoring program using satellite remote sensing, field and ground measurements, and models and assessments. The proposed program builds on existing activities throughout the world and is designed to simultaneously meet the needs of the international policy, global change research, and national resource management. Outputs from this program would provide support to the Framework Convention on Climate Change, lead to the development of consistent country-level emission inventories, and address important scientific problems in global change research such as closing the global carbon budget.     

京津冀城市群大气污染传输规律研究——两组排放清单的比较分析

利用WRF/CALPUFF耦合模型,在同样重污染气象条件下,选择了当下模拟应用最广的两组排放清单对4种主要污染物（NO_x,SO₂,PM_2.5和PM₁₀）进行京津冀城市间区域传输贡献比较分析.其中一组排放清单来自政府的环境统计（以下称：环统排放清单）,另一组排放清单是来自中国多尺度排放清单（以下称：MEIC排放清单）.污染物的浓度空间分布表明,两种排放清单下污染物浓度均呈现北部以唐山中心,南部以石家庄-邯郸为中心的分布特征,均是由两个浓度最高的中心向外逐渐降低.但是环统排放清单下模拟的污染物浓度高值区范围更大,更接近实际监测数据.基于不同的清单输入,一些城市的传输角色存在一些差异.例如,对于4种污染物,两种排放清单模拟出的沧州与周边城市的净传输方向完全相反,在MEIC排放清单中,沧州以向外净传输为主,即为源;而在环统排放清单中,沧州则变成了净输入城市,即为汇.这些结论将影响大气联防联控中各城市源汇责任的认定,在实际环境管理中应注重多源数据的选择、验证和比较.     

Comparison of CH4 emission inventory data and emission estimates from atmospheric transport models and concentration measurements

CH₄ emissions from two sources of emission inventory data i.e. the National Communications and the EDGAR/GEIA database, are compared with emission estimates from six global and two regional atmospheric transport models. The emission inventories were compiled using emission process parameters to establish emission factors and statistical data to derive activity data. The emission estimates were derived from an evaluation of atmospheric transport modelling results and measured concentrations of CH₄. The comparison of emission inventories and the emissions derived from atmospheric transport models shows the largest differences on the global scale to occur in biogenic CH₄ emissions, i.e. by wetlands and biomass burning. Anthropogenic CH₄ emissions due to oil and gas production and distribution, also appear rather uncertain, especially with respect to the spatial distribution of the sources. A comparison of CH₄ emissions on a smaller scale (NW Europe) showed a fair amount of agreement between National Communications, EDGAR data and results of inverse atmospheric modelling. Because most of the CH₄ emissions in this area come from reasonably well-known CH₄ emission sources like ruminants and landfills, this is a good argument. CH₄ emission from some areas in the North Sea was underestimated by inventories. This could be due to CH₄ emissions of oil production platforms in the North Sea.