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准确评估中国森林碳汇潜力与增汇成本的经济可行性,是科学制定碳中和林业行动方案的基础。然而针对中国森林碳汇潜力与增汇成本的不同结果差异明显,可靠性需要进一步验证。为此,基于相关文献,采用Meta分析方法,对中国森林碳汇潜力与增汇成本及其导致差异的原因展开评估。研究表明:(1)中国森林碳汇量呈现不断增长的态势,但不同研究对森林碳汇潜力测度结果存在较大差异。(2)中国森林增汇的平均成本为220.45元/t CO2e(区间值为3.9~1457.02元/t CO2e),与工业减排成本相比,中国森林增汇更具有经济可行性,但波动幅度较大。(3)评估方法采用、碳库数量选择等因素是导致已有森林碳汇潜力文献估计结果差异的关键因素;森林增汇成本差异则主要受碳汇成本测度研究方法、成本收益数据来源等因素影响。(4)中国森林增汇对碳中和的贡献将会持续增加。基于研究结果,提出进一步深化森林碳汇潜力与成本测算相关研究等方面的政策建议。 相似文献
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为加快CDM项目的开发,以广西为试点,采用自下而上的方法针对其重点行业的二氧化碳减排潜力进行评价,具体地包括:高耗能工业(冶金、有色金属、建材、化工、制糖、造纸等)、电力(火电、水电、风电)、户用沼气池、木薯制燃料酒精、有机废液利用等。结果表明到2010年广西上述领域的碳减排潜力(以碳计)可达1623万t。为促进广西的可持续发展,不仅应在水电、风电、提高能效等已有方法学的领域积极开展CDM项目,还应加强其它领域如木薯制燃料酒精、户用沼气池等CDM方法学以及CDM项目的开发。 相似文献
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清洁发展机制(CDM)项目的开发,既有利于发达国家温室气体减排任务的实现,又有利于发展中国家技术的进步。针对高浓度有机废水的特点,结合河北省石家庄市某酿酒厂废水处理沼气发电项目,对高浓度有机废水处理中的沼气发电CDM项目进行了分析,根据CDM方法学AMS-III-H计算该项目的减排量。结果表明,在CDM机制下该项目年减排量预计为39,378 tCO2,并可以获得可观的资金收益。大大减少了温室气体的排放量,具有良好的社会、经济和环境效益。 相似文献
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Robert J. Zomer Antonio Trabucco Louis V. Verchot Bart Muys 《Mitigation and Adaptation Strategies for Global Change》2008,13(3):219-239
Within the United Nations Framework Convention on Climate Change (UNFCCC) Kyoto Protocol, countries have significant latitude
to define a forest. The most important parameter affecting area designated as forest is the minimum crown cover which can
be set between 10 and 30%. The choice will have implications for the amount of land available in a country for afforestation
and reforestation activities within the Clean Development Mechanism (CDM-AR). In this paper, we present an analysis of the
regional differences in land availability for CDM-AR projects. We then examine how the choice of a high or low threshold value
for crown cover will affect the area available for CDM activities and how the limitations imposed by this element of the definition
compares to other factors that are likely to limit CDM activities. Results represent a global analysis that included all countries
not included in Annex I of the Kyoto Protocol, and examined the effect on land availability of a range of crown cover thresholds
ranging from 10–30%. Of the 140 Non-Annex One countries, 107 countries were found to have a potential for CDM-AR projects.
Asia had the largest amount of combined area suitable for CDM-AR at the 10% crown cover threshold level. However, at 30%,
South America had the greatest amount of land available, and a large change in available land area, which increased by almost
five times compared to what was available at the 10% threshold. The area available in Africa increased by a factor of 5.5.
Central America showed the largest increase, to almost 10 times more at the 30% threshold. By contrast, within Asia, the area
increase was comparatively less, but still the area nearly doubled. Globally, a low threshold of 10% crown cover excluded
almost 2/3 of the land identified that was eligible at 30%, over 5 million km2. The spatial analyses showed not only the effects of the choice of the crown cover criterion, but also where the land was
available for CDM activities within each country at different thresholds. Protected areas account for 10–20% of the CDM-AR
eligible area in most countries. 相似文献
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采用走航连续观测系统分别在2011年5月和2015年5月对南海北部表层水体温度、盐度、溶解氧、叶绿素a和pCO_2进行了现场观测.在El Nio影响下,2015年5月华南地区及广东省降雨量偏多,大量冲淡水入海,南海北部冲淡水区域海表盐度显著降低,2015年5月冲淡水区域海表盐度平均值为(28.05±6.18),低于2011年5月的海表盐度平均值(29.65±2.58),同时实测冲淡水区域海表温度平均升高约2.10℃.冲淡水携带的营养物质和适度升高的海表温度共同促进了冲淡水区域浮游植物的繁殖.浮游植物光合作用不断地将海水中的游离CO2转化为有机碳,同时释放出氧气,使得水体pCO_2降低,2015年5月冲淡水区域pCO_2平均值为(286±95)μatm,低于2011年5月的pCO_2平均值(300±42)μatm.2015年5月实测获得离岸海域pCO_2平均值为(421±9)μatm,高于2011年5月pCO_2平均值(386±13)μatm,二者差值为35μatm,海表温度是离岸海域pCO_2的主要影响因子,2015年5月El Nio期间离岸海域SST升高1.96℃.El Nio影响下冲淡水区域的碳汇作用增加,离岸海域的碳源作用增强,冲淡水区域碳汇增加与离岸海域碳源增强基本抵消,2015年5月南海北部整体仍是CO_2弱汇区,约为-0.40 mmol·m~(-2)·d~(-1),与2011年5月通量值-0.58 mmol·m~(-2)·d~(-1)差别不明显. 相似文献
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Dibenzothiophene (DBT) degradation mechanisms and the transformation of pathways during the incubation of three types of coastal sediments with C/N ratios ranging from 1 to 9 were investigated. The DBT degradation efficiencies were clearly improved with increasing C/N ratio in reed wetland sediments, tidal wetlands sediments and estuary wetland sediments. The quantitative response relationships between DBT degradation rates and related functional genes demonstrate that the Kodama pathway-related gene groups were dominant factors at low C/N ratios, while the 4S-related gene groups mainly determined the degradation rate when the C/N ratio was up to 5. Network analysis also shows that the pathway shifts from the Kodama pathway to the 4S pathway occurred through changes in the connections between functional genomes and rates. Furthermore, there were competition and collaboration between the Kodama and 4S pathways. The 4S pathway-related bacteria were more active in estuary wetland sediments compared with reed wetland sediments and tidal wetland sediments. The higher degradation efficiency in estuary wetland sediments may indicate the greater participation of the 4S pathway in the DBT biodegradation reaction. And the effects of ring cleavage of Kodama pathway caused more complete metabolizing of DBT. 相似文献
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Overwhelming evidence reveals that concentrations of dissolved organic carbon (DOC) have increased in streams which brings negative environmental impacts. DOC in stream flow is mainly originated from soil-water solutions of watershed. Wetlands prove to be the most sensitive areas as an important DOC reserve between terrestrial and fluvial biogeosystems. This reported study was focused on the distribution characteristics and the controlling factors of DOC in soil-water solutions of annular wetland, i.e., a dishing wetland and a forest wetland together, in the Sanjiang Plain, Northeast China. The results indicate that DOC concentrations in soilwater solutions decreased and then increased with increasing soil depth in the annular wetland. In the upper soil layers of 0-10 cm and 10-20 cm, DOC concentrations in soil-water solutions linearly increased from edge to center of the annular wetland (R^2 = 0.3122 and R^2 = 0.443). The distribution variations were intimately linked to DOC production and utilization and DOC transport processes in annular wetland soil-water solutions. The concentrations of total organic carbon (TOC), total carbon (TC) and Fe(II), DOC mobility and continuous vertical and lateral flow affectext the distribution variations of DOC in soil-water solutions. The correlation coefficients between DOC concentrations and TOC, TC and Fe(II) were 0.974, 0.813 and 0.753 respectively. These distribution characteristics suggested a systematic response of the distribution variations of DOC in annular wetland soil-water solutions to the geometry of closed depressions on a scale of small catchments. However, the DOC in soil pore water of the annular wetland may be the potential source of DOC to stream flow on watershed scale. These observations also implied the fragmentation of wetland landscape could bring the spatial-temporal variations of DOC distribution and exports, which would bring negative environmental impacts in watersheds of the Sanjiang Plain. 相似文献