碳税政策对农业土地利用变化及其碳排放的影响

农业生态系统具有碳源和碳汇的双重特征,其在减缓气候变化中的重要性已得到国际社会的广泛认可。相较于技术手段的创新,碳税、补贴等经济手段被认为是较为简单、可行、易出台的碳排放减缓政策。采用气候变化综合评估模型-GOPer-GC模型,构建国际碳税情景,模拟分析了2008年至2050年碳税政策的实施对全球各区域农业土地覆被及土地利用变化碳排放的影响。模拟结果表明,情景2和情景3中全球农业土地利用变化累计碳排放分别达到49.6 GtC和23.1 GtC,明显低于基准情景的累计排放量51.9 GtC。这说明,实施碳税政策后,相较于将碳税收入用作一般性财政收入,将碳税收入补贴至农业部门在一定程度上减缓农业碳排放。此外,林业部门获取更多的碳税补贴时,多数区域农业土地利用变化碳排放规模大幅减少,主因是耕地变为林地、草地变为林地面积的增加。情景3中,中国的碳汇量较其他情景显著增加,主要来自耕地变为林地、草地变为林地,累计碳汇量分别达到1.7和3.7 GtC。因此,对于中国、美国、印度等大部分区域来说,碳税收入更多地补贴至林业部门有利于在整体上减缓农业碳排放,而欧盟、日本、东亚、马来西亚、印度尼西亚、俄罗斯、东欧地区,碳税收入平均补贴至种植业、畜牧业和林业反而具有相对更好的减排效果。     

中国征收碳税应对碳关税的经济分析——以美国为例

碳税和碳关税作为一种价格调整机制,长期而言会对经济系统中各主体产生较强的约束力。通过GTAP-E模型的模拟分析,得出以下结论:在目前的发展阶段,碳关税并非有效的低碳经济发展政策,尤其是美国对中国征收碳关税对降低世界碳排放量的影响有限;美国针对中国采取的碳关税政策将在一定程度上对我国出口贸易产生负向影响,尤其是对中国的高碳产业影响较大;当中美采取相同的碳税政策时,碳税的征收对中国GDP造成较大的负面影响,且中国自主采取节能减排方案不足以应对美国碳关税的负面效应;而当两者采取差异化政策时,中国主动采取节能减排行动可以有效应对美国碳关税的威胁。     

能源对北京市城市碳循环的影响

研究城市碳循环过程并阐明能源对碳循环的影响,可为城市节能减排政策的制定和实施提供参考依据。基于城市碳循环模型核算了2005—2014年北京市的碳储量和碳通量,并通过能源碳效应指数来探讨能源对城市碳循环的影响。结果表明人为碳储量是北京市总碳储量增加的主要驱动力。北京市的碳输入主要来自水平方向,表明北京市的发展在很大程度上依赖于外部环境的物质供给;北京市的碳输出主要是能源消耗产生的垂直碳输出。能源活动相关的碳通量占北京市总碳通量的比重,即能源碳效应,在2006年高达79.46%,而后开始呈波动下降的趋势。能源对北京市碳循环影响最大的是垂直输出方向,其次是水平输入方向,因此低碳城市建设需要加强对垂直碳通量和水平碳通量的调节和管理,尤其是与能源活动相关的碳通量,与此同时,保护自然植被和增加生态用地对提高城市碳减排能力也至关重要。     

中国增汇型气候保护政策实施对经济的影响

系统地给出了中国实施增汇型CO2减排政策对宏观经济影响的模拟结果,所采用的模拟系统包括基于Pizer,Demeter,Zwaan工作发展的中国气候保护决策支持系统和中国经济可计算一般均衡(CGE)系统。研究结果表明,增汇型气候保护政策较其他单一的气候保护政策更有利于国家经济安全;虽然增汇型气候保护政策在短期内会对国家GDP产出造成影响,但从长远角度看,增汇型气候保护将带动经济的发展,是一项值得推广的减排政策。同时,发现中国实行每年增加4%的碳汇和实施4%能源替代以减少CO2排放控制率,辅助于0.2%的生产型CO2排放控制率,如果能够促进世界其它地区到2050年减排1990年的10%的CO,是一个合适的方案。     

京津冀城市群能源协同发展背景下能源生产结构变化探究

能源作为城市生产与生活中不可替代的资源类型,在城市化发展过程具有至关重要的作用。工业革命时代的结束,信息时代的开始,标志着以化石燃料为主要原料的发展方式发生转变,能源生产结构随着化石燃料比重下降而优化。城市群成为当前城市化的主体形态,其发展战略对区域能源结构具有重要影响。以京津冀城市群为例,从地级市尺度核算了2001—2015年不同城市能源生产结构的特征及其变化,并分析了城市群能源协同发展战略对不同城市能源生产结构的影响。主要结论包括:(1)2001—2015年京津冀各城市能源生产结构整体上趋于优化,但能源生产化石燃料占主导地位的本质特点没有改变。例如,河北的邯郸和邢台市增加了一次电力生产,但原煤生产仍占比90%以上。(2)研究根据能源生产的主导类型,可将京津冀城市划分为两类,即原煤主导型与原油主导型城市。其中,原煤主导型城市能源生产结构的调整明显优于原油主导型城市,例如,北京、石家庄、张家口与承德等原煤主导型城市的煤炭生产比重显著下降,而天津与沧州市等原油主导型城市的原油生产无明显下降趋势。(3)京津冀能源协同发展战略的实施有助于推进能源生产结构的优化,但对不同城市的影响不同,其中,对北京和河北承德市能源生产结构优化最显著,2001—2015年原煤生产比例下降了近40%,与协同发展战略的"基本无煤矿"目标方向一致,而对邯郸市、邢台市影响不明显。京津冀城市群能源生产结构调整仍具有较大潜力,对于原煤生产比例最高的城市(邯郸和邢台市),需要加快城市的能源生产转型,增加清洁能源产出,改善能源生产单一的结构特点;对于原煤生产产量较高的城市(唐山市),需要根据资源禀赋情况逐步调整原煤产量,进一步集约地区煤矿,同时鼓励发展煤炭洗选业,提高煤炭清洁生产技术;对于具有"无煤矿化"目标的高煤产城市(承德市和张家口市),需加快淘汰落后产能,同时依托京津冀能源协同发展战略,充分利用自身自然风力优势和区位优势,大力发展新能源。     

北京市住宅建筑生命周期碳足迹

从生命周期角度看,建筑碳足迹与能源和建材生产系统具有密切关系。随着技术的进步和节能政策的推进,中国能源的生产和使用,以及建材生产过程中的环境排放都随着时间在持续降低,这将间接地影响到建筑的环境表现。依据1990—2010年期间每5a的中国能源与建材生命周期清单数据,对北京市20年间住宅建筑系统开展生命周期评价和碳足迹核算,以揭示北京市住宅建筑系统的环境负荷变化特征。结果表明,北京市住宅建筑生命周期碳足迹随时间推移呈现降低趋势,主要来自能源系统和建材生产系统的碳减排贡献。不同结构建筑的碳足迹尽管有差异,但也呈现了相似的下降趋势。从生命周期阶段看,建筑碳足迹主要体现在建筑使用阶段和建材生产阶段。尽管建筑使用阶段的节能对于降低建筑生命周期碳足迹具有重要贡献,但节能在经济成本及环境成本方面而言是有限度的。在可持续的环境政策管理制定中,应从生命周期角度,统筹考虑协调各行业减碳的协调发展。论文同时也验证了在生命周期评价中考虑时间变量将有助于更好地利用生命周期评价结果支持环境可持续管理。结论对于城市规划的政策制定、量化环境表现是有益的。     

泛长三角地区碳生态效率的空间格局及影响因素

碳生态效率反映碳排放产出的经济社会价值高低,是衡量可持续发展水平的重要指标。以泛长三角各市为对象,以揭示碳排放的经济社会效益为目标,构建经济产出效率和人口承载效率评估指标,研究碳生态效率的空间格局和影响因素。结果表明：经济产出效率和人口承载效率呈现不同的变化趋势和空间格局,2000-2014年,经济产出效率增长97%,人口承载效率下降68%,前者空间集聚度高于后者;核心区及部分沿江城市的经济产出效率较高、增长较快,人口承载效率较低、下降较慢,碳生态效率高于其他城市;经济产出和人口承载效率的影响因素类似、作用强度和方向不同,前者主要受产业结构促进,后者的影响因素包括但不限于产业结构,但产业结构优化抑制了人口承载效率提升。研究认为,经济和社会视角的碳生态效率变化趋势及影响因素作用方向存在差异,为通过政策调控实现经济和社会效益同步提升增加了难度,在推动经济增长的同时,进一步加快人口集聚、优化产业结构和能源结构、提高能源利用效率等是政策制定的优选方向。     

干旱能源植物的发掘与应用策略

随着人类社会的快速发展和对化石能源的不合理开采,化石能源整体可开采量锐减;另一方面,化石能源的大量使用造成日益凸显的环境污染问题,发展生物质能源对解决能源危机、促进社会可持续发展具有重要意义。囿于人口持续增长和粮食需求不断增加,发展能源植物的重要突破口在于大力开发不与粮食作物争地争水的干旱能源植物。因此,从能源植物概念及其意义入手,论述国内外干旱能源植物应用现状和在实际种植生产过程中存在的问题,综合分析适合作为干旱能源植物的新类型,进而提出干旱能源植物的应用策略。     

基于LEAP的厦门市节能与温室气体减排潜力情景分析

城市是人类社会经济活动的中心,聚集了世界一半以上的人口。在城市发生的温室气体排放量占全球排放总量的75%左右,因此在城市这个尺度上研究温室气体减排意义重大。从城市这个尺度出发,以厦门市为实际研究案例,应用LEAP模型进行节能减排政策情景分析,定量分析评价城市节能减排潜力,并详细分析各种控制情景和各部门的节能减排贡献率。研究结果显示:在综合控制情景下,厦门能源消费总量年均增长率、万元地区生产总值能耗和温室气体排放总量年均增长率都有所下降;清洁燃料替代措施节能减排效果最好,工业部门节能减排潜力最大;优化能源使用结构蕴藏巨大减排潜力。     

基于LMDI分解的厦门市碳排放强度影响因素分析

研究碳排放强度的变化趋势及其影响因素对于指导低碳城市建设具有重要意义。应用对数平均权重分解法(LMDI),基于厦门市2005—2010年各部门终端消费数据对碳排放强度指标进行因素分解,并将传统分析仅注重产业部门的能源碳排放,拓展到全面考虑产业部门和家庭消费的能源活动和非能源活动影响。研究结果表明:2005—2010年厦门市碳排放强度下降17.29%,其中产业部门能源强度对总碳排放强度变化影响最大(贡献63.07%),家庭消费能源强度是碳排放强度下降的主要抑制因素(-45.46%)。从影响效应角度看,经济效率对碳排放强度下降贡献最大,碳排系数减排贡献最小;从部门减排贡献角度看,第二产业贡献最大,家庭消费贡献最小。总体而言,厦门市未来碳减排重点部门在第二产业,优化产业结构和能源结构有较大减排潜力。     

Recycle,Bury, or Burn Wood Waste Biomass?: LCA Answer Depends on Carbon Accounting,Emissions Controls,Displaced Fuels,and Impact Costs

This study extends existing life cycle assessment (LCA) literature by assessing seven environmental burdens and an overall monetized environmental score for eight recycle, bury, or burn options to manage clean wood wastes generated at construction and demolition activity sites. The study assesses direct environmental impacts along with substitution effects from displacing fossil fuels and managed forest wood sourcing activities. Follow‐on effects on forest carbon stocks, land use, and fuel markets are not assessed. Sensitivity analysis addresses landfill carbon storage and biodegradation rates, atmospheric emissions controls, displaced fuel types, and two alternative carbon accounting methods commonly used for waste management LCAs. Base‐case carbon accounting considers emissions and uptakes of all biogenic and fossil carbon compounds, including biogenic carbon dioxide. Base‐case results show that recycling options (recycling into reconstituted wood products or into wood pulp for papermaking) rank better than all burning or burying options for overall monetized score as well as for climate impacts, except that wood substitution for coal in industrial boilers is slightly better than recycling for the climate. Wood substitution for natural gas boiler fuel has the highest environmental impacts. Sensitivity analysis shows the overall monetized score rankings for recycling options to be robust except for the carbon accounting method, for which all options are highly sensitive. Under one of the alternative methods, wood substitution for coal boiler fuel and landfill options with high methane capture efficiency are the best for the overall score; recycling options are next to the worst. Under the other accounting alternative, wood substitution for coal and waste‐to‐energy are the best, followed by recycling options.     

中国能源消费碳排放的时空特征

选择联合国政府间气候变化专门委员会(IPCC)的部门方法和8大类能源,采用1990年至2009年的中国能源统计数据,按照自下而上的思路,对我国各省区的碳排放量进行估算,并从碳排放量、碳排放强度、人均碳排放量和碳排放密指标出发,深入分析了各省区碳排放的时空特征差异。以期对国内碳排放的时空特征分析,有助于决策者和能源分析家提高节能减排政策制定的有效性。     

基于土地利用变化的四川省碳排放与碳足迹效应及时空格局

土地利用变化的碳排放与碳足迹研究对了解人类活动对生态环境的扰动程度及其机理、制定有效的碳排放政策具有重要意义。采用1990—2010年四川省能源消费数据和土地利用数据,通过构建碳排放模型、碳足迹及其压力指数模型,对研究区20年来土地利用的碳排放及碳足迹进行了定量分析。结果表明:(1)土地利用变化的碳排放和能源消费碳的足迹呈显著增加趋势。碳排放增加5407.839×10~4t,增长率达143%;能源消费的碳足迹增加1566.622×10~4hm~2,四川全省的生态赤字达1563.598×10~4hm~2。(2)建设用地和林地分别为四川省最大的碳源与碳汇。20年间建设用地的碳排放增加5407.072×10~4t,增长率达126.27%,占碳排放总量的88%以上;林地的碳汇减少10.351×10~4t,但仍占四川省碳汇的96%以上。(3)土地利用碳排放、碳足迹和生态赤字存在明显区域差异。成都平原区碳排放、碳足迹压力最大,生态赤字严重,西部高山高原区和盆周山区碳排放、碳足迹最小,未出现生态赤字;成都、德阳、资阳和内江等地的碳排放、碳足迹压力最大,生态赤字最严重,甘孜、阿坝等地的碳排放、碳足迹最小,未出现生态赤字。(4)土地利用结构与碳排放、碳足迹存在一定的相互关系,趋高的碳源、碳汇比导致土地利用的碳源效应远大于碳汇效应。因此,四川省减排的重点应该在保持或增加现有的林地的同时,主要以降低建设用地的碳排放、碳足迹为主。     

Assessing “Dangerous Climate Change”: Required Reduction of Carbon Emissions to Protect Young People,Future Generations and Nature

We assess climate impacts of global warming using ongoing observations and paleoclimate data. We use Earth’s measured energy imbalance, paleoclimate data, and simple representations of the global carbon cycle and temperature to define emission reductions needed to stabilize climate and avoid potentially disastrous impacts on today’s young people, future generations, and nature. A cumulative industrial-era limit of ∼500 GtC fossil fuel emissions and 100 GtC storage in the biosphere and soil would keep climate close to the Holocene range to which humanity and other species are adapted. Cumulative emissions of ∼1000 GtC, sometimes associated with 2°C global warming, would spur “slow” feedbacks and eventual warming of 3–4°C with disastrous consequences. Rapid emissions reduction is required to restore Earth’s energy balance and avoid ocean heat uptake that would practically guarantee irreversible effects. Continuation of high fossil fuel emissions, given current knowledge of the consequences, would be an act of extraordinary witting intergenerational injustice. Responsible policymaking requires a rising price on carbon emissions that would preclude emissions from most remaining coal and unconventional fossil fuels and phase down emissions from conventional fossil fuels.     

Biogenic vs. geologic carbon emissions and forest biomass energy production

In the current debate over the CO₂ emissions implications of switching from fossil fuel energy sources to include a substantial amount of woody biomass energy, many scientists and policy makers hold the view that emissions from the two sources should not be equated. Their rationale is that the combustion or decay of woody biomass is simply part of the global cycle of biogenic carbon and does not increase the amount of carbon in circulation. This view is frequently presented as justification to implement policies that encourage the substitution of fossil fuel energy sources with biomass. We present the opinion that this is an inappropriate conceptual basis to assess the atmospheric greenhouse gas (GHG) accounting of woody biomass energy generation. While there are many other environmental, social, and economic reasons to move to woody biomass energy, we argue that the inferred benefits of biogenic emissions over fossil fuel emissions should be reconsidered.     

煤矿固废资源化利用的生态效率与碳减排——以淮北市为例

工业固废的大量堆积产生多种环境危害,工业固废的资源化利用能够节约资源和缓解环境压力。建筑行业是能源消耗和碳排放的主要部门之一,其中建筑材料生产阶段的能耗和碳排放占有重要的地位。粉煤灰、煤矸石是常见的工业固体废物,尤其是在以煤炭为主要能源的地区。粉煤灰、煤矸石资源化利用的途径之一是用于制造新型墙体砖。本文以煤炭资源型城市淮北市的新型墙体砖(粉煤灰砌块、煤矸石砖)和传统墙体砖(粘土砖、粘土多孔砖)为案例,对墙体砖生产过程的生态效率和碳排放进行分析和比较。在淮北市墙体材料行业碳排放不增加的前提下,以最优生态效率为目标,建立线性规划模型,对淮北市4种主要墙体材料的产量进行规划。分析结果表明:新型墙体材料的生态效率高于传统墙体材料;煤矸石砖生产过程的碳排放系数高于传统墙体砖;粉煤灰砌块生产过程的碳排放系数介于粘土砖和粘土多孔砖之间。在淮北市墙体材料行业碳排放不增加的前提下,与现有的产量相比,淮北市应禁止粘土砖的生产,适当减少粘土多孔砖的产量,适当增加粉煤灰砌块和煤矸石砖的产量,以达到最优生态效率。在最优生态效率的情况下,淮北市新型墙体材料煤矸石砖对煤矸石工业固废的利用率将由目前的15.8%增加到25.2%。     

The time aspect of bioenergy – climate impacts of solid biofuels due to carbon dynamics

The climate impacts from bioenergy involve an important time aspect. Using forest residues for energy may result in high initial emissions, but net emissions are reduced over time since, if the residues were left on the ground, they would decompose and release CO₂ to the atmosphere. This article investigates the climate impacts from bioenergy with special focus on the time aspects. More specifically, we analyze the climate impacts of forest residues and stumps where combustion related emissions are compensated by avoided emissions from leaving them on the ground to decompose. These biofuels are compared with fossil gas and coal. Net emissions are defined as emissions from utilizing the fuel minus emissions from a reference case of no utilization. Climate impacts are estimated using the measures radiative forcing and global average surface temperature. We find that the climate impacts from using forest residues and stumps depend on the decomposition rates and the time perspective over which the analysis is done. Over a 100 year perspective, branches and tops have lower climate impacts than stumps which in turn have lower impacts than fossil gas and coal. Over a 20 year time perspective, branches and tops have lower climate impacts than all other fuels but the relative difference is smaller. However, stumps have slightly higher climate impacts over 20 years than fossil gas but lower impacts than coal. Regarding metrics for climate impacts, over shorter time scales, approximately 30 years or less, radiative forcing overestimates the climate impacts compared with impacts expressed by global surface temperature change, which is due to the inertia of the climate system. We also find that establishing willow on earlier crop land may reduce atmospheric CO₂, provided new land is available. However, these results are inconclusive since we haven't considered the effects of producing the agricultural crops elsewhere.     

Contextualizing ethanol avoided carbon emissions in Brazil

We propose to compare avoided emissions from ethanol use in Brazil with emissions caused by the use of fossil fuel, and by land use changes, specifically Amazon deforestation. The avoided emissions of CO₂ in Brazil due to ethanol use in 2008 ranged from approximately 9 to 12 Tg C yr^?1. These values are an order of magnitude higher than the amount of carbon that could be potentially sequestered in soils if sugarcane cultivation in Brazil switches completely to mechanized harvesting, and two orders of magnitude higher than the carbon emissions in soils cultivated with sugarcane and that undergo harvest with burning. In relation to fossil fuel emissions, ethanol avoided emissions are equivalent to 20–30% of the carbon emissions associated with the use of gasoline and diesel in the transportation sector, and to approximately 10% of the total use of fossil fuel in the country. When compared with the carbon emissions from Amazon deforestation ethanol avoided emissions are again one order of magnitude lower. We conclude that ethanol avoided emissions are relatively important within the transport sector, but are still incipient if compared with the emissions from total fossil fuel combustion and emissions from deforestation indicating that climate mitigation efforts in Brazil needs to focus outside of biofuel production. Consequently, we suggest that Brazil develop equally strong actions towards increased energy efficiency use in the country and, more importantly to drastically reduce carbon emissions associated with Amazon deforestation.     

Life cycle assessment of corn grain and corn stover in the United States

Background, aim, and scope  The goal of this study is to estimate the county-level environmental performance for continuous corn cultivation of corn grain and corn stover grown under the current tillage practices for various corn-growing locations in the US Corn Belt. The environmental performance of corn grain varies with its farming location because of climate, soil properties, cropping management, etc. Corn stover, all of the above ground parts of the corn plant except the grain, would be used as a feedstock for cellulosic ethanol. Materials and methods  Two cropping systems are under investigation: corn produced for grain only without collecting corn stover (referred to as CRN) and corn produced for grain and stover harvest (referred to as CSR). The functional unit in this study is defined as dry biomass, and the reference flow is 1 kg of dry biomass. The system boundary includes processes from cradle to farm gate. The default allocation procedure between corn grain and stover in the CSR system is the system expansion approach. County-level soil organic carbon dynamics, nitrate losses due to leaching, and nitrogen oxide and nitrous oxide emissions are simulated by the DAYCENT model. Life cycle environmental impact categories considered in this study are total fossil energy use, climate change (referred to as greenhouse gas emissions), acidification, and eutrophication. Sensitivities on farming practices and allocation are included. Results  Simulations from the DAYCENT model predict that removing corn stover from soil could decrease nitrogen-related emissions from soil (i.e., N₂O, NO _x , and NO₃ ⁻ leaching). DAYCENT also predicts a reduction in the annual accumulation rates of soil organic carbon (SOC) with corn stover removal. Corn stover has a better environmental performance than corn grain according to all life cycle environmental impacts considered. This is due to lower consumption of agrochemicals and fuel used in the field operations and lower nitrogen-related emissions from the soil. Discussion  The primary source of total fossil energy associated with biomass production is nitrogen fertilizer, accounting for over 30% of the total fossil energy. Nitrogen-related emissions from soil (i.e., N₂O, NO _x , and NO₃ ⁻ leaching) are the primary contributors to all other life cycle environmental impacts considered in this study. Conclusions  The environmental performance of corn grain and corn stover varies with the farming location due to crop management, soil properties, and climate conditions. Several general trends were identified from this study. Corn stover has a lower impact than corn grain in terms of total fossil energy, greenhouse gas emissions, acidification, and eutrophication. Harvesting corn stover reduces nitrogen-related emissions from the soil (i.e., N₂O, NO _x , NO₃ ⁻). The accumulation rate of soil organic carbon is reduced when corn stover is removed, and in some cases, the soil organic carbon level decreases. Harvesting only the cob portion of the stover would reduce the negative impact of stover removal on soil organic carbon sequestration rate while still bringing the benefit of lower nitrogen-related emissions from the soil. No-tillage practices offer higher accumulation rates of soil organic carbon, lower fuel consumption, and lower nitrogen emissions from the soil than the current or conventional tillage practices. Planting winter cover crops could be a way to reduce nitrogen losses from soil and to increase soil organic carbon levels. Recommendations and perspectives  County-level modeling is more accurate in estimating the local environmental burdens associated with biomass production than national- or regional-level modeling. When possible, site-specific experimental information on soil carbon and nitrogen dynamics should be obtained to reflect the system more accurately. The allocation approach between corn grain and stover significantly affects the environmental performance of each. The preferred allocation method is the system expansion approach where incremental fuel usage, additional nutrients in the subsequent growing season, and changes in soil carbon and nitrogen dynamics due to removing corn stover are assigned to only the collected corn stover.     

Forest bioenergy climate impact can be improved by allocating forest residue removal

Bioenergy from forest residues can be used to avoid fossil carbon emissions, but removing biomass from forests reduces carbon stock sizes and carbon input to litter and soil. The magnitude and longevity of these carbon stock changes determine how effective measures to utilize bioenergy from forest residues are to reduce greenhouse gas (GHG) emissions from the energy sector and to mitigate climate change. In this study, we estimate the variability of GHG emissions and consequent climate impacts resulting from producing bioenergy from stumps, branches and residual biomass of forest thinning operations in Finland, and the contribution of the variability in key factors, i.e. forest residue diameter, tree species, geographical location of the forest biomass removal site and harvesting method, to the emissions and their climate impact. The GHG emissions and the consequent climate impacts estimated as changes in radiative forcing were comparable to fossil fuels when bioenergy production from forest residues was initiated. The emissions and climate impacts decreased over time because forest residues were predicted to decompose releasing CO₂ even if left in the forest. Both were mainly affected by forest residue diameter and climatic conditions of the forest residue collection site. Tree species and the harvest method of thinning wood (whole tree or stem‐only) had a smaller effect on the magnitude of emissions. The largest reduction in the energy production climate impacts after 20 years, up to 62%, was achieved when coal was replaced by the branches collected from Southern Finland, whereas the smallest reduction 7% was gained by using stumps from Northern Finland instead of natural gas. After 100 years the corresponding values were 77% and 21%. The choice of forest residue biomass collected affects significantly the emissions and climate impacts of forest bioenergy.