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51.
Specific fossil carbon (C) emissions and primary energy useassociated with the manufacture of different wood product groups inFinland are estimated and expressed as emissions or energy use per amountof wood-based C in raw material and per amount in end product. Thecalculation includes both emissions from supplied fuels within the forestindustries, and from electricity and district heat purchased from externalsources. The results are compared to fossil C emissions from the wholelifecycle of harvested wood products. The results of the study show, forinstance, that the emission of fossil C per wood-based C in end products(MgC/MgC) is of the order of 0.07 for sawn wood and 0.3–0.6 for paperin the manufacturing stage. The primary energy use per wood-based C inend product is of the order of 2 MWh/MgC for sawn wood, whereas forvirgin paper grades the figure is between 17 and 19 MWh/MgC. Theprimary energy content is highest in papers based on chemical pulping, butaround 60% of the energy used is produced in this case from by-productwood wastes (black liquor, bark etc.). The specific fossil C emission andprimary energy divided by the estimated service life of the wood productare measures for the relative burden of maintaining the corresponding woodproduct pool. These figures should be kept in mind when considering woodproducts as a potential C sink option.  相似文献   
52.
松属(Pinus L.)约113种,是松科现代属中最原始的类群。松属植物种类丰富且研究领域广泛,对其已经积累的资料数据进行系统梳理总结十分必要。本文通过总结国内外松属大化石资料,结合分子系统发育、地质背景和地理隔离事件讨论了其地史分布及植物地理学意义;该属化石在早白垩世至全新世地层中均有记录。化石证据表明松属很可能在早白垩世(之前)起源于西欧地区,从这一起源地通过北大西洋陆桥扩散到北美洲东部,而东亚的类群可能是从北美洲西部经过白令陆桥散布的。在晚白垩世分化出双维管束松亚属Subgenus Pinus L.及单维管束松亚属Subgenus Strobus (D.Don) Lemmon,前者更接近祖先类群。古新世由于全球显著增温以及白垩纪末期大灭绝等地质事件的影响使松属数量急剧减少,在晚始新世至中新世时期随着气温转凉转冷再次分化扩散,中新世达到其发展高峰且分布面貌与现代类群近似。松属多样性时空历史可能和新生代气候变迁及晚新生代构造运动塑造的山地隆升等环境变化紧密相关。  相似文献   
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54.
广东连县水足塘下石炭统六个层位发育丰富的遗迹化石,遗迹大都保留于灰岩、泥灰岩中,共计有九个遗迹属及类型,它们是Zoophycos管状潜穴,Chondrites,Thalassinoides,Teichichnus?枝状潜穴,不规则状潜穴。Planolites和Ancorlchnus。其中刘家塘组下部发现管状潜穴;中上部发现Zoophycos、Thalassinoides、不规则状潜穴Chondrites、Teichichnus?及枝状潜穴,它们形成一遗迹组合;石蹬子组发现Chondrites及Ancourichnus;梓门桥组发现Zoophycos及Planolites.此组合形成于开阔台地相,成员形成于不同时的底质,分属Zoophycos和Glossifungites两个遗迹相。  相似文献   
55.
浙江省上石炭统-中二叠统生物地层划分进展   总被引:2,自引:0,他引:2  
本文划分论述了浙江省上石炭统—中二叠统16条化石带(其中11条为新建化石带),对比研究结果表明它们分布于老虎洞组、黄龙组、船山组、梁山组、栖霞组、孤峰组、龙潭组下部的地层,可分别与滑石板阶、达拉阶、逍遥阶、紫松阶、隆林阶、栖霞阶、祥播阶、茅口阶、冷坞阶等9个阶对比。探讨研究了上石炭统底界、下二叠统底界和中二叠统底界;指出上石炭统未见底,缺失罗苏期的沉积;下二叠统底界位于Sphaeroschwagerina subrotunda带之底,以Sphaeroschwagerina属的始现作为底界的标准;石炭—二叠系界线位于Triticites subcrassulu筵带与Sphaeroschwagerina subrotund筵带之间;中二叠统的底界位于Orthotichia chekiangensis腕足组合带之底,以Orthotichia chekiangensis的始现作为中二叠统底界的标准。进一步论证了船山组是一个跨越石炭—二叠系界线的岩石地层单位,下部归属上石炭统逍遥阶,中部归属下二叠统紫松阶和上部归属下二叠统隆林阶。  相似文献   
56.
三波长红外法测定水中石油类和动植物油   总被引:1,自引:0,他引:1  
张锐 《云南环境科学》2001,20(2):63-64,11
根据油的种类,性质及水中的分布情况,采用优级纯四氯化碳多次萃取,将油从水中提取出来,包含石油类和动物物油,动物物油属极性物质,可被硅酸吸附,石油类不被吸附,在红外三波长,波数分别为2930cm^-1,2960cm^-1,3030cm^-1处被吸收,准确测定这三个波数特征谱带的总和,从而准确测定水中石油类和动植物油。  相似文献   
57.
Based on over one year of participant observation within the student-led fossil fuel divestment (FFD) movement, this article contextualises the origins, successes, challenges, and inner workings of the FFD movement in US higher education. We analyse several college divestment campaigns to illuminate key factors that have contributed to wins and rejections, and explore why students continue to organise for FFD. It is our contention that such widespread mobilisation for FFD signals a sea change, from individualised sustainability efforts to youth-led collective political action, and recognition of climate change as a social justice issue. In addition to participant observation, we gathered data from 23 survey responses of organisers involved in divestment campaigns within higher education, and 40 interviews with individuals including student and professional organisers within the FFD movement, institutional decision-makers at campuses with FFD campaigns, and other experts in the area. Our analysis also reveals that relatively smaller endowments and, more importantly, institutional values of environmental sustainability and social justice played key roles in colleges’ decision to divest. Our examination of divestment “losses” illuminates common arguments administrators deploy in their rejection statements, including the perceived costs of divestment, the need to maintain fiduciary responsibility, and scepticism that divestment will have any impact on the fossil fuel industry. Finally, in spite of increasing resistance from college and university administrations, student divestment campaigns continue to escalate, and are committed to organising over the long term.  相似文献   
58.
The fossil fuel divestment movement has been a vibrant novel development in climate change politics in recent years, particularly in North America. Here, the character of the discourse used to promote divestment as a strategy is explored. The divestment discourse is shown to rest on four overlapping narratives, those of war and enemies, morality, economics and justice. All four are clearly discernible in statements from movement activists, in coverage of divestment campaigns by major news sources and in the movement’s aims, objectives and strategies covered in alternative media. The war narrative, with the formulation of fossil fuel companies as enemies to be overcome to ensure survival, is the dominant narrative. By polarising climate action and identifying an antagonist against which to mobilise, divestment discourse has articulated climate change as an explicitly political phenomenon, in contrast to the primarily consensus and collaboration-based approaches that have predominated in climate politics.  相似文献   
59.
In pursuit of socioeconomic development, many countries are expanding oil and mineral extraction into tropical forests. These activities seed access to remote, biologically rich areas, thereby endangering global biodiversity. We examined how protection of biodiversity and economic revenues can be balanced in biologically valuable regions. Using spatial data on oil profits and predicted species and ecosystem extents, we optimized the protection of 741 terrestrial species and 20 ecosystems of the Ecuadorian Amazon across a range of opportunity costs (i.e., sacrifices of extractive profit). We also applied spatial statistics to remotely sensed, historic deforestation data to focus the optimization on areas most threatened by imminent forest loss. Giving up 5% of a year's oil profits (US$221 million) allowed for a protected area network that retained an average of 65% of the extent of each species and ecosystem. This performance far exceeded that of the network produced by simple optimization for land area (which required a sacrifice of approximately 40% of annual oil profits [US$1.7 billion]) and used only marginally less land to achieve equivalent levels of ecological protection. We identified what we call emergency conservation targets: regions that are essential components of a cost-effective conservation reserve network but at imminent risk of destruction, thus requiring urgent and effective protection. Governments can use our methods when evaluating extractive-led development options to responsibly manage the associated ecological and economic trade-offs and protect natural capital.  相似文献   
60.
中国化石能源消费碳排放与经济增长关系研究   总被引:7,自引:1,他引:6  
化石能源过度消费导致的气候变化问题引发了全世界对经济发展模式的关注,论文运用计量经济学方法研究了中国化石能源消费碳排放与经济增长的关系,测算了中国1953-2010年化石能源消费引起的碳排放总量,建立了碳排放总量和国内生产总值的时序计量经济模型,通过协整检验、误差修正模型、基于VAR模型的脉冲响应函数、因果关系检验,分析了二者之间的长短期关系,结果表明:1953-2010年,我国的化石能源消费碳排放总量和国内生产总值之间存在长期均衡的协整关系和短期动态调整机制,通过短期调节,可以自动实现二者之间的长期均衡。当期GDP对碳排放总量的当期波动有显著性影响,每增加1%的GDP便会增加0.719%的碳排放量,上期误差对碳排放总量的当期波动调整幅度较大,单位调整比例为-0.102。利用脉冲响应函数波形图对碳排放量与经济增长之间的影响及响应进行了20期的详细刻画,揭示了二者之间复杂的短期动态关系。1953-2010年,存在从碳排放总量到GDP的单向Granger因果关系,碳排放是经济增长的Granger原因,而经济增长不是碳排放的Granger原因,说明从过去58 a的整体状况来看,高碳排放推动了经济增长,而经济增长并未导致明显的碳排放增加。研究结果将对中国制定节能减排和碳减排政策提供依据和支撑。  相似文献   
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