温度和水分对中亚热带人工林生态系统呼吸的调控作用

全球气候变化导致的降水格局改变影响陆地生态系统碳收支状况。陆地生态系统所固定的碳主要通过呼吸作用返回到大气中,而温度和水分是调节生态系统呼吸的重要因素。ChinaFLUX千烟洲中亚热带人工林通量站夏季雨热不同季而造成的季节性干旱为探讨温度和水分对生态系统呼吸的调控作用提供了天然的试验条件。研究利用该生态系统2003-2010年涡度相关和常规气象数据,阐述了生态系统呼吸对温度和土壤含水量的响应特征,对比分析了只考虑温度与同时考虑温度和土壤含水量对生态系统呼吸的季节模式和年呼吸量的影响。研究表明,生态系统呼吸的季节变异主要受土壤温度的控制,呈现指数响应特征。但是,在干旱胁迫条件下,土壤含水量对生态系统呼吸的季节变异起到明显的调控作用。参考温度下的生态系统呼吸(R_ref)明显受土壤含水量的影响。生态系统年呼吸量为1 289.4±73.9 gC·m^-2·a^-1,两类模型的估算结果没有显著差异。但是在生态系统的季节变异上,两类模型估算存在显著差异,同时考虑温度与土壤含水量的模型更适合模拟遭受干旱胁迫的生态系统呼吸。     

城市复合生态系统能值整合分析研究方法论

系统阐述了城市复合生态系统能值分析的基本概念原理与方法步骤,总结了城市可持续发展综合能值评价指标体系。在此基础上,从能值转换率的积累和统一、多尺度研究的整合与尺度推绎、城市功能流分析与空间结构分析的整合、能值成本价值论与使用(市场)价值论的整合等方面,讨论了能值研究方法在城市生态系统研究中的应用前景和发展方向。     

Firms' and states’ responses to laxer environmental standards

On June 1, 2017, President Trump announced the United States' withdrawal from the Paris agreement on climate change. Despite this decision, American firms continued investing in low-carbon technologies and some states committed to tougher environmental standards. To understand this apparent paradox, this paper studies how a weakening of environmental standards affects the behavior of profit-maximizing firms. It finds that a relaxation of emission standards (i) may increase firms’ incentives to adopt clean technologies, but not to pollute less; (ii) may negatively affect industry profitability if it is perceived as temporary; and, when this is the case, (iii) the unilateral adoption of stricter standards by large states may increase the expected profitability of every firm.     

Microclimate effects of wind farms on local crop yields

This paper considers a novel spillover effect of wind farms - microclimate impacts on neighboring crop yields. Using US county-level crop and wind capacity data, I examine the effects of wind energy development on crop yields, controlling for time-invariant county characteristics and state-level annual shocks. I find robust evidence that counties with increased wind power development have also experienced increased corn and other crop yields, such that an additional 100 MW of wind capacity increases county yields by roughly 1%. At recent prices, this implies a more than $5 dollar per megawatt-hour local benefit, corresponding to several hundred million dollars in annual benefits.     

Strategic implications of counter-geoengineering: Clash or cooperation?

Solar geoengineering has received increasing attention as an option to temporarily stabilize global temperatures. A key concern is that heterogeneous preferences over the optimal amount of cooling combined with low deployment costs may allow the country with the strongest incentive for cooling, the so-called free-driver, to impose a substantial externality on the rest of the world. We analyze whether the threat of counter-geoengineering technologies capable of negating the climatic effects of solar geoengineering can overcome the free-driver problem and tilt the game in favour of international cooperation. Our game-theoretical model of countries with asymmetric preferences allows for a rigorous analysis of the strategic interaction surrounding solar geoengineering and counter-geoengineering. We find that counter-geoengineering prevents the free-driver outcome, but not always with benign effects. The presence of counter-geoengineering leads to either a climate clash where countries engage in a non-cooperative escalation of opposing climate interventions (negative welfare effect), a moratorium treaty where countries commit to abstain from either type of climate intervention (indeterminate welfare effect), or cooperative deployment of solar geoengineering (positive welfare effect). We show that the outcome depends crucially on the degree of asymmetry in temperature preferences between countries.     

Personality and economic choices

There is substantial variation in individual preferences for public goods, yet much of that variation remains poorly understood. However, simple measures of personality can help to explain economic values and choices in a systematic way. In this paper, we examine the effects of personality on individual economic choices over public environmental goods. Based on three datasets from three separate stated preference studies, we use a hybrid choice econometric framework to examine the effects of personality on preferences for the status quo, changes in environmental quality, and costs of investing in environmental improvements. We find effects that are consistent across all datasets. Personality, a stable feature of an individual's character that is simple to measure, enriches explanations of why the demand for environmental goods varies across people, provides an indication of how different people are likely to react to the introduction of environmental policies, and explains substantial differences in Willingness to Pay.     

When do environmental regulations backfire? Onsite industrial electricity generation,energy efficiency and policy instruments

More than half of all energy produced by electric utilities is lost in the form of waste heat. However, when manufacturing facilities choose to produce their own electricity, this waste heat is captured by Combined Heating and Power (CHP) technologies and used in the production process. As a result, manufacturers' pollution footprint can be dramatically reduced by choosing to produce electricity onsite rather than purchasing it from a utility. This paper uses Census microdata to study manufacturers’ decision to produce electricity onsite and examines how plants adjust onsite generation when they are subject to environmental regulations. Environmental regulations will backfire if they cause manufacturers to produce less electricity onsite and shift to electricity from less efficient, offsite electric utilities. We find that manufacturing plants subject to NOx command-and-control regulations decrease onsite electricity generation, increase electricity purchases from off-site utilities and see declines in their energy efficiency. However, manufacturers subject to cap-and-trade see no decline in onsite generation and experience improvements in energy efficiency. These findings demonstrate the importance of instrument selection and identify a new pathway through which emissions leakage may occur.     

The environmental effects of trade within and across sectors

This paper presents a model that combines within and across sector channels through which trade affects our environment by embedding heterogeneous firms and fixed costs into a two-sector framework with an endogenous response to environmental policy. In contrast to existing literature that tends to examine these channels separately, the combined framework developed here shows how cross-sector comparative advantage and within-sector responses to trade and environmental policy or factor endowments interact to affect our environment through three channels: changes in output, cross-sector market share, and emissions intensity. In contrast to a single-sector model with neutral productivity, consideration of two sectors allows for trade liberalization to affect the allocation of inputs in each sector and thereby affect total pollution output. The additional consideration of heterogeneous firm responses to falling trade costs will generate endogenous increases in productivity that increase output, reduce aggregate emissions intensity, and moderate the cross-sector resource adjustment, relative to a representative-firm model. Simulation results show how the combined framework can replicate existing empirical outcomes, and provide concise ceteris paribus insights regarding the potential role of trade and environmental policy changes and factor expansion in driving observed outcomes and their contribution to each of the three channels.     

Urban afforestation and infant health: Evidence from MillionTreesNYC

This paper examines the impact of urban afforestation on infant health outcomes by exploiting a quasi-experimental setting where one million new trees were planted in New York City (NYC), but not in counties surrounding NYC over the same time period. Using a near-universal birth record of NYC and surrounding counties over 2004–2015 and employing both the synthetic control method and a difference-in-differences model, we find that an approximately 20% increase in urban forest cover decreased prematurity and low birth weight among mothers in NYC by 2.1 and 0.24 percentage points, respectively, relative to similar mothers outside of NYC. The low birth weight finding is equivalent to getting a mother smoking two cigarettes a day during pregnancy to quit. An internal validity test suggests that changes in the composition of NYC mothers cannot explain the observed effects. Additionally, we find evidence that declines in PM_2.5 concentrations and increases in outdoor walks are potential causal mechanisms. Results suggest that urban afforestation may be able to complement existing policies aimed at improving infant health.     

人的安全心理特性研究方法的综述研究

通过搜寻中国学术期刊全文数据库,查阅近年来期刊发表的有关心理特性研究方法方面的98篇论文。从概念、研究方法分类、研究方法特点、研究方法优缺点对质的研究和量的研究分别进行了比较和汇总分析;指出当前我国心理特性研究方法的现状、存在的问题与发展趋势;提出只有将"质"与"量"的方法进行整合,使之进行优势互补,才是未来心理研究领域发展的必然趋势。运用心理特性研究方法可更准确地了解人的心理活动,最大限度地避免人的不安全行为,从而减少事故的发生。