林业碳汇项目基准线和监测方法学及应用分析——以贵州省贞丰县林业碳汇项目为例

气候变化给全球社会经济发展带来了重大影响,林业碳汇在适应和减缓气候变化、促进可持续发展三方面的重要作用日益被世界各国所认可。林业碳汇项目实施的难点在于准确掌握林业碳汇项目设计的规则、标准体系,重点在于基准线判别、碳汇计量、监测的方法学和工具。本文系统介绍了国际清洁发展机制造林再造林(CDM A/R)项目方法学和国内碳汇造林项目方法学、标准体系等最新成果,并以贵州省贞丰县林业碳汇项目为例,分析了基准线和监测方法学在林业碳汇项目开发设计中的实际应用。     

Analyzing the efficacy of subtropical urban forests in offsetting carbon emissions from cities

Urban forest management and policies have been promoted as a tool to mitigate carbon dioxide (CO₂) emissions. This study used existing CO₂ reduction measures from subtropical Miami-Dade and Gainesville, USA and modeled carbon storage and sequestration by trees to analyze policies that use urban forests to offset carbon emissions. Field data were analyzed, modeled, and spatially analyzed to compare CO₂ sequestered by managing urban forests to equivalent amounts of CO₂ emitted in both urban areas. Urban forests in Gainesville have greater tree density, store more carbon and present lower per-tree sequestration rates than Miami-Dade as a result of environmental conditions and urbanization patterns. Areas characterized by natural pine-oak forests, mangroves, and stands of highly invasive trees were most apt at sequestering CO₂. Results indicate that urban tree sequestration offsets CO₂ emissions and, relative to total city-wide emissions, is moderately effective at 3.4 percent and 1.8 percent in Gainesville and Miami-Dade, respectively. Moreover, converting available non-treed areas into urban forests would not increase overall CO₂ emission reductions substantially. Current CO₂ sequestration by trees was comparable to implemented CO₂ reduction policies. However, long-term objectives, multiple ecosystem services, costs, community needs, and preservation of existing forests should be considered when managing trees for climate change mitigation and other ecosystem services.     

山东黄河下游流域土壤碳储量及时空变化研究

全球气候变暖及其影响是当前人类面临的重大环境问题之一,大气CO2浓度的剧增为人类生活带来的诸多环境问题越来越严重。土壤有机碳是陆地生态系统碳库的重要组成部分,它的微小变化直接影响大气温室气体的浓度。本文利用2003~2010年多目标区域地球化学调查及20世纪80年代全省第二次土壤普查碳数据,对山东省黄河下游流域土壤碳密度、碳储量及时空变化规律和固碳潜力与机制进行了研究,结果表明,1.0 m土层有机碳库约占我国SOCP的3.28%;表现出"碳汇";水稻土碳密度最高、砂姜黑土次之,滨海盐土最低;研究区0~1.0 m土层固碳潜力为1.02×109t,相当于可减少大气中0.081%CO2浓度。通过相关性分析表明,在土壤中增施有机肥和N、P、K肥,以及施用Zn等矿质肥料可有效提高土壤中的有机碳量,提升土壤固碳能力,而含Cl量过高是滨海土壤固碳的破坏性因素。本研究为缓解大气CO2浓度的剧增的环境压力,发挥和提高我国土壤生态系统的固碳潜力提供了科学依据。     

生态系统固碳特征及其研究进展

生态系统固碳是人类应对气候变化以及全球系统变化过程的研究热点。论文结合生态系统固碳和碳汇概念,探讨生态系统自然固碳、人为工程固碳措施对生态系统功能的影响并分析生态系统固碳特征及风险。研究得出如下结论:陆地生态系统对CO₂的自然吸收与封存是相对安全有效的固碳措施,对人类与生态系统健康的影响要小于地质层与海洋层固碳。海洋生态系统固碳容易导致海水酸化以及生态系统不可逆的损害;由于地壳运动很难预测,所以地质层固碳可能面临不可预知的风险。因此,利用生态系统自然固碳能力、发展绿色固碳技术是降低人为工程固碳生态风险和减少CO₂排放到大气中的最佳选择。     

Regulatory Constraints to Carbon Sequestration in Terrestrial Ecosystems and Geologic Formations: A California Perspective

Carbon sequestration in terrestrialecosystems and geologic formations providesa significant opportunity for California toaddress global climate change. The physicalsize of its resources (e.g., forests,agriculture, soils, rangeland, and geologicformations) and the expertise in Californiaprovides a substantial foundation fordeveloping carbon sequestration activities.Furthermore, the co-benefits of carbonsequestration – such as improved soil andwater quality, restoration of degradedecosystems, increased plant and cropproductivity, and enhanced oil recovery – are significant. In fact, carbonsequestration often represents a `noregrets' strategy – implementing carbonsequestration provides multiple benefits,even without the advent of global climatechange.Nevertheless, researchers need to addressseveral issues to determine more accuratelythe potential, benefits, and costs ofsequestering carbon in California'sterrestrial ecosystems and geologicformations, as well as to identify the mostpromising sequestration methods and theiroptimal implementation. One key issue isthe type of regulatory constraints facingdevelopers of carbon sequestrationprojects: what permits are needed fordeveloping these projects? The permittingprocess may impede the penetration ofsequestration technologies into the marketif the costs (including transaction costs)of obtaining the permits are too burdensomeand costly. For example, at least ninefederal regulations and seven stateregulations will potentially influencecarbon sequestration projects inCalifornia. This paper also provides anexample of the types of permits needed fordeveloping a carbon sequestration project,using California as an example. It ispossible that a carbon sequestrationproject may have to obtain a total of 15permits (3 federal, 6 state, 6 local),before it even starts to operate. In theconcluding section, we offer some suggestedareas for research and activities forpolicy makers.     

遥感技术与陆地生态系统碳循环研究

在人类社会日益关注全球环境问题的今天,大气中CO2和CH4等温室气体浓度升高诱发的全球气候变化已成为可持续发展的最严峻挑战。因此,针对各个陆地生态系统的碳循环研究成为气候变化和区域发展研究的重点和关键。陆地生态系统中土地利用方式、植被种类等的变化,通过时间和空间的尺度来影响着全球碳循环,而遥感技术具有宏观、速度快、周期短、信息量大、多时相等特点,因此在植被覆盖和土地利用分类、碳循环遥感模型等方面都有着重要的应用。     

Establishing A Earth Observation Product Service For The Terrestrial Carbon Community: The Globcarbon Initiative

'Greenhouse gases', especially carbon dioxide, are intimately connected to climate change. To understand the future evolution of the climate system and find ways to manage the concentration of atmospheric carbon dioxide, the processes and feedbacks that drive the carbon cycle must first be understood. However, our current knowledge of spatial and temporal patterns is uncertain, particularly over land and in regions of potentially high sensitivity to change like the boreal zone. The European Space Agency (ESA) GLOBCARBON project aims to generate fully calibrated estimates of at-land products quasi-independent of the original Earth Observation source for use primarily in Dynamic Global Vegetation Models, but also as a contribution to the Global Carbon Project, a cooperation between the International Geosphere Biosphere Programme, International Human Dimensions Programme and the World Climate Research Programme to aid understanding of global carbon cycling. The service will feature estimation of global burned area, the fraction of absorbed photosynthetically active radiation (f_APAR), leaf area index (LAI) and Vegetation Growth Cycle. The demonstrator will focus on ten complete years, from 1998 to 2007 when overlap exists between ESA Earth Observation sensors and others that are synergistic. However, the system will be flexible so that it is not dependent on any single satellite sensor and therefore can be retrospectively applied to existing archives and used with future satellite sensors.     

中国西南喀斯特森林土壤有机碳空间变化及影响因素

喀斯特地区土壤碳储量及其影响因素的认识是评估我国陆地土壤生态系统碳汇能力不可或缺的内容。本文通过对中国西南北起秦岭北坡南至中越边境一条剖面上土壤有机碳的分析,研究了喀斯特森林0~10cm土壤有机碳空间变化及其控制因素。研究发现西南地区土壤有机碳含量和碳密度平均为32.3 g/kg和33.1t/hm2。无论是在整个西南区还是其省市范围内,二者均低于非喀斯特森林土壤。通径分析表明,影响喀斯特表层土壤碳含量和密度的主要因素有土壤容重、地形海拔和有机质C/N;粘粒含量和年平均气温的影响很小,而降水量仅在地处最北部的陕西省构成了土壤碳密度的影响因素。此现象与世界许多地区特别是高纬度地区形成鲜明对比。本研究结果表明,不同区域/气候带土壤碳库的主要影响因素会存在很大差异,这对认识气候变化背景下土壤碳库的反馈作用具有重要意义。     

A new way of carbon accounting emphasises the crucial role of sustainable timber use for successful carbon mitigation strategies

The roles of forest management and the use of timber for energy in the global carbon cycle are discussed. Recent studies assert that past forest management has been accelerating climate change, for example in Europe. In addition, the increasing tendency to burn timber is an international concern. Here, we show a new way of carbon accounting considering the use of timber as a carbon neutral transfer into a pool of products. This approach underlines the robust, positive carbon mitigation effects of sustainable timber harvesting. Applying this new perspective, sustainable timber use can be interpreted not as a removal but a prevention of carbon being converted within the cycle of growth and respiration. Identifying timber use as a prevention rather than a removal leads to the understanding of timber use as being no source of carbon emissions of forests but as a carbon neutral transfer to the product pool. Subsequently, used timber will then contribute to carbon emissions from the pool of forest products in the future. Therefore, timber use contributes to carbon mitigation by providing a substantial delay of emissions. In a second step, the carbon model is applied to results of a previous study in which different timber price scenarios were used to predict timber harvests in Bavarian forests (Germany). Thus, the influence of the economic dimension “timber price” on the ecological dimension carbon sequestration was derived. It also shows that these effects are stable, even if an increasing tendency of burning timber products for producing energy is simulated. Linking an economic optimization to a biophysical model for carbon mitigation shows how the impact of management decisions on the environment can be derived. Overall, a sustainably managed system of forests and forest products contributes to carbon mitigation in a positive, stable way, even if the prices for (energy) wood rise substantially.     

全球二氧化碳浓度非均匀分布条件下碳排放与升温关系的统计分析

为定量评估全球二氧化碳浓度非均匀分布条件下碳排放与升温的关系,采用空间自相关分析与空间联立方程组模型,基于1度、2度与3度空间分辨率的全球二氧化碳浓度,碳排放与近地面气温等格点数据,揭示了2003—2015年全球二氧化碳浓度的空间分布聚集特征并估计了碳排放对升温的影响系数。结果发现：二氧化碳浓度在空间上表现为北半球高浓度值聚集与南半球低浓度值聚集的分布型。利用二氧化碳浓度非均匀分布的参数条件对碳排放与升温影响的估计结果表明,代入二氧化碳浓度非均匀分布这一参数会小幅拉低碳排放对升温影响的估计结果。研究表明,全球二氧化碳浓度非均匀分布是当前评估碳排放升温影响亟待引入的参数;同时由于估计结果的空间尺度效应的存在,相关参数的空间范围与分辨率的选择也需要关注。     

Potential carbon sequestration in China’s forests

Forests are believed to be a major sink for atmospheric carbon dioxide. There are 158.94 million hectares (Mha) of forests in China, accounting for 16.5% of its land area. These extensive forests may play a vital role in the global carbon (C) cycle as well as making a large contribution to the country’s economic and environmental well-being. Currently there is a trend towards increased development in the forests. Hence, accounting for the role and potential of the forests in the global carbon budget is very important.In this paper, we attempt to estimate the carbon emissions and sequestration by Chinese forests in 1990 and make projections for the following 60 years based on three scenarios, i.e. “baseline”, “trend” and “planning”. A computer model F-CARBON 1.0, which takes into account the different biomass density and growth rates for the forests in different age classes, the life time for biomass oxidation and decomposition, and the change in soil carbon between harvesting and reforestation, was developed by the authors and used to make the calculations and projections. Climate change is not modelled in this exercise.We calculate that forests in China annually accumulate 118.1 Mt C in growth of trees and 18.4 Mt in forest soils, and release 38.9 Mt, resulting in a net sequestration of 97.6 Mt C, corresponding to 16.8% of the national CO₂ emissions in 1990. From 1990 to 2050, soil carbon accumulation was projected to increase slightly while carbon emissions increases by 73, 77 and 84%, and net carbon sequestration increases by −21, 52 and 90% for baseline, trend and planning scenarios, respectively. Carbon sequestration by China’s forests under the planning scenario in 2000, 2010, 2030 and 2050 is approximately 20, 48, 111 and 142% higher than projected by the baseline scenario, and 8, 18, 34 and 26% higher than by the trend scenario, respectively. Over 9 Gt C is projected to accumulate in China’s forests from 1990 to 2050 under the planning scenario, and this is 73 and 23% larger than projected for the baseline and trend scenarios, respectively. During the period 2008–2012, Chinese forests are likely to have a net uptake of 667, 565 and 452 Mt C, respectively, for the planning, trend and baseline scenarios. We conclude that China’s forests have a large potential for carbon sequestration through forest development. Sensitivity analysis showed that the biggest uncertainty in the projection by the F-CARBON model came from the release coefficient of soil carbon between periods after harvesting and before reforestation.     

Vulnerability of land systems to fire: Interactions among humans,climate, the atmosphere,and ecosystems

Fires are critical elements in the Earth System, linking climate, humans, and vegetation. With 200–500 Mha burnt annually, fire disturbs a greater area over a wider variety of biomes than any other natural disturbance. Fire ignition, propagation, and impacts depend on the interactions among climate, vegetation structure, and land use on local to regional scales. Therefore, fires and their effects on terrestrial ecosystems are highly sensitive to global change. Fires can cause dramatic changes in the structure and functioning of ecosystems. They have significant impacts on the atmosphere and biogeochemical cycles. By contributing significantly to greenhouse gas (e.g., with the release of 1.7–4.1 Pg of carbon per year) and aerosol emissions, and modifying surface properties, they affect not only vegetation but also climate. Fires also modify the provision of a variety of ecosystem services such as carbon sequestration, soil fertility, grazing value, biodiversity, and tourism, and can hence trigger land use change. Fires must therefore be included in global and regional assessments of vulnerability to global change. Fundamental understanding of vulnerability of land systems to fire is required to advise management and policy. Assessing regional vulnerabilities resulting from biophysical and human consequences of changed fire regimes under global change scenarios requires an integrated approach. Here we present a generic conceptual framework for such integrated, multidisciplinary studies. The framework is structured around three interacting (partially nested) subsystems whose contribute to vulnerability. The first subsystem describes the controls on fire regimes (exposure). A first feedback subsystem links fire regimes to atmospheric and climate dynamics within the Earth System (sensitivity), while the second feedback subsystem links changes in fire regimes to changes in the provision of ecological services and to their consequences for human systems (adaptability). We then briefly illustrate how the framework can be applied to two regional cases with contrasting ecological and human context: boreal forests of northern America and African savannahs.     

Project Specific Monitoring and Verification: State of the Art and Challenges

Adequate monitoring of carbon sequestered by forestry activities is essential to the future of forestry as a climate change mitigation option. A wide range of approaches has been taken to monitor changes in forest carbon attributable to project activities. This paper describes simple, least-cost/least-precision methods, remote sensing, periodic carbon inventories, and traditional research methods. Periodic carbon inventories are the preferred approach because they are cost-effective, provide measurements with known levels of precision, and allow the monitoring of other values such as biodiversity and commercial timber volumes. Verification of monitoring estimates is discussed as an auditing process designed to evaluate reported carbon sequestration values. The limitations of remote sensing for biomass determination and the potential for changes in monitoring approaches due to improvements in technology are briefly reviewed.     

The impact of climate change under different thinning regimes on carbon sequestration in a German forest district

The objective of this paper is to assess how much carbon (C) is currently stored in a forest district in Thuringia, Germany, and how the carbon stocks will develop up to the year 2099 with a changing climate and under various management regimes (including no management), with different assumptions about carbon dioxide (CO₂) fertilization effects. We applied the process-based model 4C and a wood product model to a forest district in Germany and evaluated both models for the period from 2002 to 2010, based on forest inventory data for the stands in the district. Then, we simulated the growth of the stands in the forest district under three different realizations of a climate change scenario, combined with different management regimes. Our simulations show that in 2099, between 630 and 1149 t C ha^?1 will be stored in this district. The simulations also showed that climate change affects carbon sequestration. The no management strategy sequestered the highest amount of carbon (8.7 t C ha^?1 year^?1), which was greater than the management regimes. In the model, the possible fertilization effect of CO₂ is an important factor. However, forest management remains the determining factor in this forest district.     

不同源汇信息提取方法对区域CO2源汇估算及其季节变化的影响评估

从大气二氧化碳(CO2)浓度观测资料中准确提取源汇或本底信息对区域及全球碳源汇及大气CO2浓度长期变化趋势的定量估计至关重要.本研究以瓦里关大气CO2浓度观测资料为例,探讨了同期地面风和同期一氧化碳(CO)浓度观测资料作为源汇信息提取或本底值筛选因子的有效性.结果表明,地面风和同期CO浓度在冬季可作为筛选因子,但是夏季将其作为筛选因子不是十分有效.采用局部近似回归法(robust estimation of background signal,REBS)、傅里叶变换法(Fourier transform algorithm,FTA)和新发展的平均移动过滤法(moving average filtering,MAF)进行大气CO2浓度源汇及本底信息提取.结果表明,MAF法因其以每2周为一个拟合窗口,采用不断变化和调整的过滤标准,避免了在局部将抬升浓度或吸收浓度百分比过高或者过低估计,优于另外两种方法.3种方法对因区域排放源导致的大气CO2的抬升量的结果无显著差异,但对因区域吸收汇导致的大气CO2降低量差异明显.结果表明,3种方法均可以对受到人类活动排放源影响的CO2抬升浓度合理地筛分,但只有MAF法可对夏季吸收浓度较好地判别.MAF法获得的1995~2008年瓦里关大气CO2多年平均季振幅为约10.3×10-6(摩尔分数,下同),与前期观测结果一致;而REBS法得到的大气CO2逐年季振幅约为9.1×10-6,将会导致低估区域或全球CO2通量值.     

Active Amplification of the Terrestrial Albedo to Mitigate Climate Change: An Exploratory Study

To date, international efforts to mitigate climate change have focussed on reducing emissions of greenhouse gases in the energy, transportation and agriculture sectors, and on sequestering atmospheric carbon dioxide in forests. Here, the potential to complement these efforts by actions to enhance the reflectance of solar insolation by the human settlement and grassland components of the Earth's terrestrial surface is explored. Preliminary estimates derived using a static two dimensional radiative transfer model indicate that such efforts could amplify the overall planetary albedo enough to offset the current global annual average level of radiative forcing caused by anthropogenic greenhouse gases by as much as 30% or 0.76 Wm^{− 2}. Terrestrial albedo amplification may thus extend, by about 25 years, the time available to advance the development and use of low-emission energy conversion technologies which ultimately remain essential to mitigate long-term climate change. While a scoping analysis indicates the technical feasibility of sufficiently enhancing human settlement and grassland albedos to levels needed to achieve reductions in radiative forcing projected here, additional study is required on two fronts. Firstly, the modelled radiative forcing reductions are static estimates. As they would generate climate feedbacks, more detailed dynamic climate modelling would be needed to confirm the stationary value of the radiative forcing reduction that would result from land surface albedo amplification. Secondly, land surface albedo amplification schemes may have important economic and environmental impacts. Accurate ex ante impact assessments would be required to validate global implementation of related measures as a viable mitigation strategy.     

全球气候变化下中国林产品的减排贡献：基于木质林产品固碳功能核算

森林及其产品的固碳功能对减缓气候变化具有重要作用。木质林产品（下简称HWP）的碳储存是全球气候变化的重要议题,研究HWP碳储量并对其进行功能管理,对我国政府提高温室气体减排潜力并参与气候谈判、提交国家温室气体排放清单具有重要的现实意义。论文依据政府间气候变化专门委员会（IPCC）建议的HWP碳量核算模型,研究了1961—2011年中国HWP的固碳功能,继而比较分析了中国HWP碳储量的减排潜力。研究表明：从总量看,储量变化法、大气流动法基础上核算的中国2011 年度碳储量值分别为6.76×10⁸ t 碳和2.58×10⁸ t 碳;从年增长量看,储量变化法、大气流动法基础核算的中国HWP碳储量增长平均值为1 063×10⁴ t 碳和262×10⁴ t 碳。基于中国是世界HWP进口大国,储量变化法的选择应用将对我国有利。HWP碳储量减排贡献的研究发现：中国HWP碳储量为森林立木总量的4.75%~8.42%,平均约为6%;对比中国能源消费的年碳排放量值,中国HWP的年碳储量可以减排约1.6%,中国HWP具有显著的碳汇功能及进一步提升的减排潜力。     

Towards science in support of decision making: characterizing the supply of carbon cycle science

As concern about climate change grows, so does interest in deliberately managing the carbon cycle to reduce atmospheric concentrations of carbon dioxide. Given the scientific and technical nature of knowledge of the carbon cycle, one would expect that carbon science would be directly of use to society in considering this objective. However, carbon science is not currently organized or conducted in such a way that it can be usable to the wide diversity of decision makers who might potentially be involved in managing the carbon cycle. This paper reviews the science policies and actors governing the production or “supply” of carbon cycle science, and suggests alternatives for enabling the supply to better meet demand.     

合肥科学岛低对流层二氧化碳时空分布特征

依据合肥市科学岛2013~2016年的CO₂体积比浓度廓线,分别从夜间、季节和年度分析了亚热带季风气候的CO₂分布特点和合肥科学岛的CO₂源汇特征.（1）大气CO₂体积比浓度随高度增加而减小,390m的CO₂浓度约为15m浓度的95%,夜间随时间推移浓度增加幅度约5%,天亮时CO₂浓度有减小的趋势;（2）测量点高度大于100m时,季节特征较明显,CO₂体积比浓度夏季最低,冬季最高,浓度相差约10×10^-6;（3）测量点高度大于100m时,2013~2016年CO₂体积比浓度的年分布随高度变化的梯度相关系数大于0.9,体积比浓度年增长约2.1648×10^-6.通过三个时间尺度的CO₂体积比浓度廓线分析得出,CO₂浓度特征是动植物活动和大气运动等共同作用的结果;CO₂长期循环过程中,存在近地面CO₂向高空的传输效应.     

Analysis of leakage in carbon sequestration projects in forestry: a case study of upper magat watershed,Philippines

The role of forestry projects in carbon conservation and sequestration is receiving much attention because of their role in the mitigation of climate change. The main objective of the study is to analyze the potential of the Upper Magat Watershed for a carbon sequestration project. The three main development components of the project are forest conservation: tree plantations, and agroforestry farm development. At Year 30, the watershed can attain a net carbon benefit of 19.5 M tC at a cost of US$ 34.5 M. The potential leakage of the project is estimated using historical experience in technology adoption in watershed areas in the Philippines and a high adoption rate. Two leakage scenarios were used: baseline and project leakage scenarios. Most of the leakage occurs in the first 10 years of the project as displacement of livelihood occurs during this time. The carbon lost via leakage is estimated to be 3.7 M tC in the historical adoption scenario, and 8.1 M tC under the enhanced adoption scenario.