重庆丘陵山区石灰性黄壤呼吸特征及影响因素

采用静态暗箱一二氧化碳红外分析仪法研究了重庆丘陵山区石灰性黄壤土壤呼吸特征及影响因素.结果表明,土壤呼吸速率呈现季节性动态变化特征,冬季较低,夏季较高,与地温的季节动态变化基本一致;土壤呼吸与地温之间呈指数关系,其中与5 cm地温的相关性最好;不同土层、不同处理的Q10值不同,变化范围为1.67～2.69.不同田间管理措施对土壤呼吸速率有明显影响,表现为施肥土壤＞未施肥处理,种植作物土壤＞裸地;化肥使种植作物土壤的年平均呼吸速率增加70.8%,化肥、粪肥共同作用增加129%;与裸地相比,单种作物不施肥不能显著增加土壤CO2排放.裸地春、秋、冬季的土壤呼吸速率与土壤水分呈直线关系,决定系数R2=0.414,P＜0.01.在夏季,种植作物未施肥和施化肥处理两者也呈直线关系,R2分别为0.5361和0.4261(P＜0.05),其他季节两者未表现出明显的规律性.     

闽江口不同沼泽植被带土壤甲烷产生潜力的温度敏感性

2012年2月采集闽江河口鳝鱼滩短叶茳芏(Cyperus malaccensis),芦苇(Phragmites australis)和互花米草(Scirpus alterniflora) 3个典型潮汐沼泽植被带0~30cm(间隔5cm)土壤样品,在不同温度(10,20和30℃)进行15d室内厌氧培养实验,探讨河口区不同沼泽植被带土壤甲烷产生潜力及其温度敏感性(Q10值)的特征.结果表明,指数模型较好地拟合不同沼泽植被带土壤甲烷产生与温度的相关关系;温度由10℃升至20℃时,3个沼泽植被带土壤甲烷产生潜力Q10值的均值分别为5.04,14.92和14.81,最大值均在培养期间的第13~15d分别出现于10~15cm,15~20cm和20~25cm三个土层;温度由20℃升至30℃时,3个沼泽植被带土壤甲烷产生潜力Q10值的均值分别为3.56,4.99和3.43,最大值分别在培养期间的第4~6d,第4~6d和第7~9d出现于0~5cm,0~5cm和15~20cm三个土层;植被类型和土壤深度对甲烷产生潜力及Q10值均具有显著的影响(P<0.05).     

The value of information for integrated assessment models of climate change

We estimate the value of information (VOI) for three key parameters of climate integrated assessment models (IAMs): marginal damages at low temperature anomalies, marginal damages at high temperature anomalies, and equilibrium climate sensitivity. Most empirical studies of climate damages have examined temperature anomalies up to 3 °C, while some recent theoretical studies emphasize the risks of “climate catastrophes,” which depend on climate sensitivity and on marginal damages at higher temperature anomalies. We use a new IAM to estimate the VOI for each parameter over a range of assumed levels of study precision based on prior probability distributions calibrated using results from previous studies. We measure the VOI as the maximum fixed fraction of consumption that a social planner would be willing to pay to conduct a new study before setting a carbon tax. Our central results suggest that the VOI is greatest for marginal damages at high temperature anomalies.     

Brown backstops versus the green paradox

Anticipated climate policies are ineffective when fossil fuel owners respond by shifting supply intertemporally (the green paradox). This mechanism relies crucially on the exhaustibility of fossil fuels. We analyze the effect of anticipated climate policies on emissions in a simple model with two fossil fuels: one scarce and dirty (e.g. oil), the other abundant and dirtier (e.g. coal). We derive conditions for a ‘green orthodox’: anticipated climate policies may reduce current emissions. The model can also be used to analyze spatial carbon leakage. Calibrations suggest that intertemporal carbon leakage (from 0% to 8%) is a relatively minor concern.     

Government green procurement spillovers: Evidence from municipal building policies in California

We study how government green procurement policies influence private-sector demand for similar products. Specifically, we measure the impact of municipal policies requiring governments to construct green buildings on private-sector adoption of the US Green Building Council?s Leadership in Energy and Environmental Design (LEED) standard. Using matching methods, panel data, and instrumental variables, we find that government procurement rules produce spillover effects that stimulate both private-sector adoption of the LEED standard and investments in green building expertise by local suppliers. These findings suggest that government procurement policies can accelerate the diffusion of new environmental standards that require coordinated complementary investments by various types of private adopter.     

492Q发动机分层进气燃烧净化节油系统研究

492Q发动机分层进气燃烧净化节油系统的研究,是为了使国产492Q发动机的油耗水平下降,同时也降低其排放对大气的污染。为此,采用稀薄燃烧原理,使发动机在空燃比(AF)为18左右也可正常燃烧,达到降低油耗,同时也减少了CH、CO、NO_x的排放。      

Incorporating environmental issues into optimum cut-off grades modeling at porphyry copper deposits

Cut-off grade is defined as the grade which discriminates between ore and waste within a given orebody. Determination of a complete optimum cut-off grade policy is a very important function during mine life. Using the modified optimum cut-off grade model presented in this paper not only the net present value of a porphyry copper mining project is maximized, but also the adverse environmental impacts of the project are minimized simultaneously. This methodology is more effective in long-range planning. For showing the effectiveness of the model, two scenarios are considered in a hypothetical deposit and the results show that incorporating the modified optimum cut-off grade policy, the net present value will be increased by 3.6% in comparison with the Base Case.     

Investor demand and spot commodity prices: Reply 2

This, our second reply to Östensson, supplements our earlier more technical analysis with a simple intuitive explanation of how investor demand can be driving commodity prices higher even when investor stocks are falling.     

Exploring the origins of ‘social license to operate’ in the mining sector: Perspectives from governance and sustainability theories

In the mining sector, local communities have emerged as particularly important governance actors. Conventional approaches to mineral development no longer suffice for these communities, which have demanded a greater share of benefits and increased involvement in decision making. These trends have been spurred by the growth of the sustainable development paradigm and governance shifts that have increasingly transferred governing authority towards non-state actors. Accordingly, there is now widespread recognition that mineral developers need to gain a ‘social license to operate’ (SLO) from local communities in order to avoid potentially costly conflict and exposure to social risks. A social license can be considered to exist when a mining project is seen as having the ongoing approval and broad acceptance of society to conduct its activities. Due to the concept's relatively recent emergence, however, only a limited body of scholarship has developed around SLO. Drawing on examples from northern Canada, this paper uses governance and sustainability theories to conceptualize the origins of SLO in the mining sector and describe some of the associated implications. Further research is needed to determine governance arrangements which help facilitate establishment of SLO in different mineral development contexts.     

Artisanal and small-scale gold mining in Burkina Faso: Suggestion of multi-agent methodology as a complementary support in elaborating a policy

In order to better manage artisanal and small-scale gold mining, the Burkinabe authorities have planned to build a suitable methodological support as an aid to elaborating appropriate policies and actions. The developed methodology concerns (a) at a spatial level, the generation and analysis of a geological resources map needed by the artisanal miners and (b) at a socioeconomic level, analysis of the miners' activity. This paper reports and discusses the results of our suggestion to also introduce the use of an approach known as multi-agent system (MAS) as a complementary part of this initial methodology, at a downstage level to the above two analysis stages. MAS methodology could be used to develop simulation models to forecast the future of the activity. MAS is appropriate for describing the dynamics of systems where it is impossible to obtain all output data of a model from a purely mathematical or statistical transformation of input data. Our suggestion involves (i) demonstrating the capacity of the approach to simulate all parameters needed by mining policy makers and (ii) evaluating to what extent the methodology is accepted by them, as well as, at a more scientific level, the literature regarding mining system simulation.