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.     

Carbon accounting for forest harvesting and wood products: review and evaluation of different approaches

Under the United Nations Framework Convention on Climate Change, more than 160 countries are required to report their national greenhouse gas inventories. To help countries meet this requirement, the Intergovernmental Panel on Climate Change (IPCC) prepared guidelines for inventorying greenhouse gases. These guidelines are regularly reviewed to ensure that they are based on the best scientific knowledge. In May 1998, in Dakar, Senegal, an IPCC expert meeting reviewed and evaluated three approaches for accounting for carbon from forest harvesting and wood products. They are the atmospheric-flow, stock-change and production approaches. In the future, governments may decide to include one of the three approaches in the land-use change and forestry module of the IPCC Guidelines for National Greenhouse Gas Inventories. Here, we demonstrate how such approaches can be evaluated using technical, scientific and policy criteria. The purpose of this evaluation is to help policy-makers potentially choose an approach for the IPCC Guidelines. This paper presents the framework of the evaluation by separating the technical and policy issues of each approach, but it does not make policy recommendations. On technical and scientific grounds, a group of experts found that the three approaches gave similar results at a global level. Data availability is not a critical factor in choosing between the approaches. However, at the national level, the approaches can differ significantly, for example, in terms of their system boundaries. Depending on technical features of each approach, credits and debits for CO₂ flows or changes in carbon stock in wood products are accounted for differently among countries that produce or consume wood. This leads to differing incentives for conserving or enhancing carbon stocks in forests, the use of imported wood products and woodfuels and waste minimisation strategies. Each approach has different implications.     

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.     

四川盆地气矿天然气开发过程中温室气体的排放特征

天然气开发过程是化石能源系统重要的排放源之一. 包括我国在内的发展中国家对于油气系统温室气体排放的研究尚处于起步阶段,并且也无统一的计算方法. 为研究我国天然气开发过程中温室气体排放情况,以四川盆地某较大规模(年产气量约16×108 m3)的天然气气矿为研究对象. 利用甲烷泄漏浓度检测仪对该气矿井口、集气站、配气站等场站的所有元件的潜在泄漏点进行了逐一检测,同时采集油田水和天然气样品,在实验室对油田水露天放置过程和天然气火炬燃烧过程的温室气体排放进行了模拟研究,计算了该矿2011年天然气开发过程中温室气体排放量. 结果表明:2011年研究气矿CH₄和CO₂排放量分别为1 033.32和1 295.56 t,折合CO₂当量为27 128.56 t. 与采用IPCC(政府间气候变化专门委员会)《2006年国家温室气体清单指南》第一层次方法计算的结果对比发现,IPCC方法计算结果(CH₄和CO₂排放量分别为20 287.39、12 479.74 t,折合CO₂当量为519 664.74 t)远高于实测法计算结果,因此,IPCC方法总体上严重高估了我国温室气体排放量.      

A distributed approach to accounting for carbon in wood products

With an evolving political environment of commitments to limit emissions of greenhouse gases, and of markets to trade in emissions permits, there is growing scientific, political, and economic need to accurately evaluate carbon (C) stocks and flows—especially those related to human activities. One component of the global carbon cycle that has been contentious is the stock of carbon that is physically held in harvested wood products. The carbon stored in wood products has been sometimes overlooked, but the amount of carbon contained in wood products is not trivial, it is increasing with time, and it is significant to some Parties. This paper is concerned with accurate treatment of harvested wood products in inventories of CO₂ emissions to the atmosphere. The methodologies outlined demonstrate a flexible way to expand current methods beyond the assumption of a simple, first-order decay to include the use of more accurate and detailed data while retaining the simplicity of simple formulas. The paper demonstrates that a more accurate representation of decay time can have significant economic implications in a system where emissions are taxed or emissions permits are traded. The method can be easily applied using only data on annual production of wood products and two parameters to characterize their expected lifetime. These methods are not specific to wood products but can be applied to long-lived, carbon-containing products from sources other than wood, e.g. long-lived petrochemical products. A single unifying approach that is both simple and flexible has the potential to be both more accurate in its results, more efficient in its implementation, and economically important to some Parties.     

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.     

Global Biomass Energy Potential

The intensive use of renewable energy is one of the options to stabilize CO₂atmospheric concentration at levels of 350 to 550ppm. A recent evaluation of the global potential of primary renewable energy carried out by Intergovernmental Panel on Climate Change (IPCC) sets a value of at least 2800EJ/yr, which is more than the most energy-intensive SRES scenario forecast for the world energy requirement up to the year 2100. Nevertheless, what is really important to quantify is the amount of final energy since the use of renewable sources may involve conversion efficiencies, from primary to final energy, different from the ones of conventional energy sources. In reality, IPCC does not provide a complete account of the final energy from renewables, but the text claims that using several available options to mitigate climate change, and renewables is only one of them, it is possible to stabilize atmospheric carbon dioxide (CO₂) concentration at a low level. In this paper, we evaluate in detail biomass primary and final energy using sugarcane crop as a proxy, since it is one of the highest energy density forms of biomass, and through afforestation/reforestation using a model presented in IPCC Second Assessment Report (SAR). The conclusion is that the primary-energy potential for biomass has been under-evaluated by many authors and by IPCC, and this under-evaluation is even larger for final energy since sugarcane allows co-production of electricity and liquid fuel. Regarding forests we reproduce IPCC results for primary energy and calculate final energy. Sugarcane is a tropical crop and cannot be grown in all the land area forecasted for biomass energy plantation in the IPCC/TAR evaluation (i.e. 1280Mha). Nevertheless, there are large expanses of unexploited land, mainly in Latin America and Africa that are subject to warm weather and convenient rainfall. With the use of 143Mha of these lands it is possible to produce 164EJ/yr (1147GJ/hayr or 3.6W/m²on average) of primary energy and 90EJ/yr of final energy in the form of liquid fuel (alcohol) and electricity, using agricultural productivities near the best ones already achievable and biomass gasification technology. More remarkable is that these results can be obtained with the operation of 4,000 production units with unitary capacity similar to the largest currently in operation. These units should be spread over the tropical land area yielding a plantation density similar to the one presently observed in the state of São Paulo, Brazil, where alcohol and electricity have been commercialized in a cost-effective way for several years. Such an amount of final energy would be sufficiently large to fulfill all the expected global increase in oil demand, as well as in electricity consumption by 2030, assuming the energy demand of such sources continues to grow at the same pace observed over the last two decades. When sugarcane crops are combined with afforestation/reforestation it is possible to show that carbon emissions decline for some IPCC SRES scenarios by 2030, 2040 and 2050. Such energy alternatives significantly reduce CO₂emissions by displacing fossil fuels and promote sustainable development through the creation of millions of direct and indirect jobs. Also, it opens an opportunity for negative CO₂emissions when coupled with carbon dioxide capture and storage.     

Impacts of international trade on carbon flows of forest industry in Finland

Finland is a forested country with a large export oriented forest industry. In addition to domestic forest extraction, roundwood is imported, thus displacing the environmental impacts of harvests. In this paper, we analyse the international carbon flows of forest industries in Finland from a consumption-based perspective. Quantitative analyses are available on trade embedded emissions of CO₂ from fossil fuel combustion, and here we address in a similar way the impact of trade on the carbon budget of the forest products sector in Finland. Carbon flows through the forest industry system increased substantially between 1991 and 2005. We show that the annual carbon balance related to forests and forest industry system in Finland functioned as a sink in 1991, whereas in 2005 the system was a sink on a national level, but not on a global level. Through calculating the carbon content in traded forest industry products and emissions embodied in forest industry activities, we further show that the direct impacts of the forest industry in Finland are only a minor fraction of the total CO₂ emissions related to Finnish production. Nearly all of the emissions were caused due to production of exports. Yet, direct carbon dioxide emissions of the industrial production are reported to Finland in the production based inventories.     

Wood materials used as a means to reduce greenhouse gases (GHGs): An examination of wooden utility poles

There has been growing concern over the build-up of greenhouse gase(GHGs) in the atmosphere, particularly carbon dioxide (CO₂), as acause of global warming. The IPCC Third Assessment Report (2001) suggests two ways in which the choice of materials could berelevant. First, some materials, particularly wood, have the advantage thatthey continue to hold carbon (C)in their cells even after being convertedto products. The implications of this feature are well researched. Second,an area that is not well researched relates to the different energyrequirements for producing similar products made with different materials. Using the findings of recent research, this paper compares the energyrequirements and C emissions of manufacturing a product using wood withthat of other materials. The case study of utility poles demonstrates thepositive C and global warming consequences of the lower energyrequirements of wood in the U.S., compared to other materials such assteel or concrete. It demonstrates that GHG emissions associated withutility poles are a small but significant percent of total US annual emissions. Wood utility poles are associated with GHG emission reductions of 163Terragrams (Tg) of CO₂ when compared with steel poles. This isabout 2.8 percent of US annual GHG emissions, which are estimated atabout 5.28 Petragrams (Pg) of CO₂ annually. Thus, the use ofwooden utility poles rather than steel results in a small but significantreduction in total US emissions.     

Greenhouse gas emissions in restored secondary tropical peat swamp forests

Restoration of deforested and drained tropical peat swamp forests is globally relevant in the context of reducing emissions from deforestation and forest degradation. The seasonal flux of carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O) in a restoration concession in Central Kalimantan, Indonesia, was measured in the two contrasting land covers: shrubs and secondary forests growing on peatlands. We found that land covers had high, but insignificantly different, soil carbon stocks of 949?+?56 and 1126?+?147 Mg ha^?1, respectively. The mean annual CO₂ flux from the soil of shrub areas was 52.4?±?4.1 Mg ha^?1 year^?1, and from secondary peat swamp forests was 42.9?±?3.6 Mg ha^?1 year^?1. The significant difference in mean soil temperature in the shrubs (31.2 °C) and secondary peat swamp forests (26.3 °C) was responsible for the difference in total CO₂ fluxes of these sites. We also found the mean annual total soil respiration was almost equally partitioned between heterotrophic respiration (20.8?+?1.3 Mg ha^?1 year^?1) and autotrophic respiration (22.6?+?1.5 Mg ha^?1 year^?1). Lowered ground water level up to ??40 cm in both land covers caused the increase of CO₂ fluxes to 40–75%. These numbers contribute to the provision of emission factors for rewetted organic soils required in the national reporting using the 2013 Supplement of the 2006 Intergovernmental Panel on Climate Change (IPCC) Guidelines for wetlands as part of the obligation under the United Nations Framework Convention on Climate Change (UNFCCC).

     

生活垃圾制备衍生燃料(RDF-5)——以重庆市为例

以重庆市生活垃圾为例,通过分选、破碎和干燥预处理后,得到以塑料、纸类、竹木、织物和厨余为主要成分的制备衍生燃料(RDF-5)的原料,测试了不同含水率和成型压力条件下制得的RDF-5的理化性质.结果表明,原料含水率为8%,成型压力为10 MPa时,RDF-5的延展率和耐性指数良好,便于贮存和运输.燃烧试验表明,RDF-5燃烧后灰渣的热灼减率满足《生活垃圾焚烧污染控制标准》(GB 18485—2014)的要求(5%).另外,根据2006 IPCC国家温室气体名录导则和生命周期评价(LCA),制备RDF-5对温室气体排放贡献为455.92 g·kg-1RDF-5(以CO2当量计).     

Reside0ntial solar water heating as a potential Clean Development Mechanism project: A South African case study

A community-based Clean Development Mechanism (CDM) project – asolar water heating project in a low-income community in South Africa –is analysed to illustrate the methodological and policy challenges that faceimplementation of the Kyoto Protocol to the United Nations FrameworkConvention on Climate Change. We evaluate four baseline options, andthree potential CDM interventions. The emissions reductions range from –670 to +5 929 Mg CO₂ per year, with all option but oneshowing positive emission reductions. Using metered solar water heatingwith liquefied petroleum gas back-up as the CDM intervention, and electricstorage geysers as the baseline, the annual emissions reductions are 5686 Mg CO₂. The cost-effectiveness from the national perspective,which is the incremental life cycle costs divided by the lifetime emissionsreductions, is –$18 per Mg CO₂ From the perspective of theCDM investor, however, the cost-effectiveness is $5.2 per mgCO₂, assuming that the investor receives all of the carbon credits forproviding the incremental capital investment. From our analysis, weconclude that using the current technology (kerosene stoves) as a baselineis probably not appropriate because it does not reflect likely future trendsand also penalises the community for their poverty and current lack ofinfrastructure. We also highlight the importance of credit sharing, and howit affects the cost-effectiveness of the project from the CDM investor'sperspective. The lessons from this analysis are important for the currentinternational policy debate on how to preferentially treat small-scale CDMprojects.     

Trees as carbon sinks and sources in the European Union

The carbon (C) sinks and sources of trees that may be accounted for under Article 3.3 of the Kyoto Protocol during the first commitment period from 2008 to 2012 were estimated for the countries of the European Union (EU) based on existing forest inventory data. Two sets of definitions for the accounted activities, afforestation, reforestation and deforestation, were applied. Applying the definitions by the Food and Agricultural Organization of the United Nations (FAO), the trees were estimated to be a C source in eight and a C sink in seven countries, and in the whole EU a C source of 5.4 Tg year⁻¹. Applying the definitions by the Intergovernmental Panel of Climate Change (IPCC), the trees were estimated to be a C source in three and a C sink in 12 countries, and in the whole EU a C sink of 0.1 Tg year⁻¹. These estimates are small compared with the C sink of trees in all EU forests, 63 Tg year⁻¹, the anthropogenic CO₂ emissions of the EU, 880 Tg C year⁻¹, and the reduction target of the CO₂ emissions, 8%. In individual countries, the estimated C sink of the trees accounted for under Article 3.3 was at largest 8% and the C source 12% compared with the CO₂ emissions.     

Managing the cost of emissions for durable,carbon-containing products

We recognize that carbon-containing products do not decay and release CO₂ to the atmosphere instantaneously, but release that carbon over extended periods of time. For an initial production of a stock of carbon-containing product, we can treat the release as a probability distribution covering the time over which that release occurs. The probability distribution that models the carbon release predicts the amount of carbon that is released as a function of time. The use of a probability distribution in accounting for the release of carbon to the atmosphere realizes a fundamental shift from the idea that all carbon-containing products contribute to a single pool that decays in proportion to the size of the stock. Viewing the release of carbon as a continuous probabilistic process introduces some theoretical opportunities not available in the former paradigm by taking advantage of other fields where the use of probability distributions has been prevalent for many decades. In particular, theories developed in the life insurance industry can guide the development of pricing and payment structures for dealing with the costs associated with the oxidation and release of carbon. These costs can arise from a number of proposed policies (cap and trade, carbon tax, social cost of carbon, etc), but in the end they all result in there being a cost to releasing carbon to the atmosphere. If there is a cost to the emitter for CO₂ emissions, payment for that cost will depend on both when the emissions actually occur and how payment is made. Here we outline some of the pricing and payment structures that are possible which result from analogous theories in the life insurance industry. This development not only provides useful constructs for valuing sequestered carbon, but highlights additional motivations for employing a probability distribution approach to unify accounting methodologies for stocks of carbon containing products.     

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.     

The effect of increasing lifespan and recycling rate on carbon storage in wood products from theoretical model to application for the European wood sector

The use of wood products is often promoted as a climate change mitigation option to reduce atmospheric carbon dioxide concentrations. In previous literature, we identified longevity and recycling rate as two determining factors that influence the carbon stock in wood products, but no studies have predicted the effect of improved wood use on carbon storage over time. In this study, we aimed at evaluating changes in the lifespan and the recycling rate as two options for enhancing carbon stock in wood products for different time horizons. We first explored the behaviour over time of both factors in a theoretical simulation, and then calculated their effect for the European wood sector of the future. The theoretical simulation shows that the carbon stock in wood products increases linearly when increasing the average lifespan of wood products and exponentially when improving the recycling rate. The emissions savings under the current use of wood products in Europe in 2030 were estimated at 57.65 Mt carbon dioxide (CO₂) per year. This amount could be increased 5 Mt CO₂ if average lifespan increased 19.54 % or if recycling rate increased 20.92 % in 2017. However, the combination of both strategies could increase the emissions saving almost 5 Mt CO₂ more by 2030. Incrementing recycling rate of paper and paperboard is the best short-term strategy (2030) to reduce emissions, but elongating average lifespan of wood-based panels is a better strategy for longer term periods (2046).     

Measuring countries’ cooperation within the international climate change regime

We present a method how to estimate and compare the cooperative behavior of countries within the international climate change regime. Two indicators measure whether and how fast countries have committed to the United Nations Framework on Climate Change (UNFCCC) and the Kyoto Protocol (KP). Three additional indicators quantify whether and how effectively measures have been implemented in line with these agreements. These three measures are reporting, financial contributions, and development of per capita CO₂ emissions in relation to the per capita gross domestic product of each country. Results show that developed countries with emission targets under the KP ratified the protocol more often and faster, submitted their report timelier, and paid their annual financial contributions to the UNFCCC secretariat more regularly than the other countries. However, concerning CO₂ emissions, developing countries are evaluated more positively than developed countries. The five indicators are aggregated to a ‘Cooperation Index’ that evaluates 198 countries’ cooperative behavior within the international climate regime on a scale between 0 (=least cooperative) and 6 (=most cooperative). According to this Cooperation Index, the following large countries are ranked after their level of cooperation in ascending order: United States of America, Australia, Russia, Canada, Brazil, China, India, South Africa, and large European countries.     

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).     

中国水泥碳排放测算的影响因素分析与不确定度计算

作为水泥生产大国和CO_2排放大户,中国水泥行业的CO_2排放在国际上受到越来越广泛的重视,然而不同的研究结果之间存在不同程度的差异.为了定量研究中国水泥碳排放测算的影响因素,对碳排放因子的测算、运营边界的界定及水泥熟料或水泥成品的产量这3个影响因素做了详细分析,并对碳排放因子的不确定度做了定量计算.结果发现,影响中国水泥碳排放测算的最主要因素是碳排放因子,而该因素又与生产工艺、燃料和熟料水泥比等密切相关.本研究结果比IPCC、EDGAR、CDIAC和WBCSD/CSI等研究结果均低,并且差异逐年显著,以水泥碳排放来自碳酸盐分解的部分为例,2000年相差约65 Mt,而2012年差值接近450 Mt.计算表明,中国水泥碳排放不确定度为12%~22%.因此,水泥碳排放测算的影响因素较多,在计算中国水泥碳排放量时不可照搬国外研究的参数.