The “second dividend” and the demographic structure

The demographic structure of a country influences economic activity. The “second dividend” modifies growth. Accordingly, in general equilibrium, the second dividend and the demographic structure are interrelated. This paper aims at assessing empirically the “second dividend” in a dynamic, empirical and intertemporal setting that allows for measuring its impact on growth, its intergenerational redistributive effects, and its interaction with the demographic structure. The paper uses a general equilibrium model with overlapping generations, an energy module and a public finance module that distinguishes between non-ageing-related public spending and a pension regime. Policy scenarios compare the consequences of different scenarios of recycling a carbon tax through lower proportional income taxes rather than higher public lump-sum expenditures. They are computed for two countries with different demographics (France and Germany). Results suggest that the magnitude of the “second dividend” is significantly related with the demographic structure. The more concentrated the demographic structure on cohorts with higher income and saving rate, the stronger the effect on capital supply of the second dividend. The second dividend weighs on the welfare of relatively aged working cohorts. It fosters the wellbeing of young working cohorts and of future generations. The more concentrated the demographic structure on aged working cohorts, the higher the intergenerational redistributive effects of the second dividend.     

A cultural model of private provision and the environment

This paper analyses an overlapping generations model of environmental externalities and capital accumulation where private contributions to environmental quality are motivated by a desire to socialize others into environmental attitudes. In this framework, the formation of environmental preferences is the result of a cultural transmission process depending on the extent of private contributions. In the short run, we show that three equilibria may arise: a first one where all green agents contribute to the environment, a second one where nobody contributes to the environment and a third interior one. We show that the capital-accumulation process and the change in preferences that occur in this economy lead the interior equilibrium to be selected, in which some, but not all, green agents contribute to the environment. The model thus provides an economic rationale for the gap between the number of people who care about the environment and the number who adopt pro-environmental behaviours. We also show that the fraction of contributors rises with capital, so that we explain the negative relationship between this gap and country income. Last, we show that this gap is particularly detrimental for welfare, and analyse the impact of a number of public policies.     

On sustainability and social welfare

This paper proposes to define sustainability in terms of leaving it possible for future generations to sustain certain defined targets. It is shown that variants of genuine savings and the ecological footprint can then serve as indicators of sustainability. The link between sustainability and intergenerational welfare is examined, and it is shown how to incorporate indicators of sustainability into a social welfare measure, including risk in the analysis.     

Response of successive three generations of cotton bollworm, Helicoverpa armigera (Hübner), fed on cotton bolls under elevated CO2

The growth, development and consumption of successive three generations of cotton bollworm, Helicoverpa armigera （Htibner）, fed on cotton bolls grown under elevated CO2 （double-ambient vs. ambient） in open-top chambers were examined. Significant decreases in protein, total amino acid, water and nitrogen content and increases in free fatty acid were observed in cotton bolls. Changes in quality of cotton bolls affected the growth, development and food utilization of H. armigera. Significantly longer larval development duration in three successive generations and lower pupal weight of the second and third generations were observed in cotton bollworm fed on cotton bolls grown under elevated CO2. Significantly lower fecundity was also found in successive three generations of H. armigera fed on cotton bolls grown under elevated CO2. The consumption per larva occurred significant increase in successive three generations and frass per larva were also significantly increased during the second and third generations under elevated CO2. Significantly lower relative growth rate, efficiency of conversion of ingested food and significant higher relative consumption rate in successive three generations were observed in cotton bollworm fed on cotton bolls grown under elevated CO2. Significantly lower potential female fecundity, larval numbers and population consumption were found in the second and third generations of cotton bollworm fed on cotton bolls grown under elevated CO2. The integrative effect of higher larval mortality rate and lower adult fecundity resulted in significant decreases in potential population consumption in the latter two generations. The results show that elevated CO2 adversely affects cotton bolls quality, which indicates the potential population dynamics and potential population consumption of cotton bollworm will alleviate the harm to the plants in the future rising CO2 atmosphere.     

The ecological footprint: an exhibit at an intergenerational trial?

This paper aims at assessing the extent to which the ecological footprint indicator (EF) can be regarded as an exhibit allowing an intergenerational trial about the use of natural resources. For that purpose, we examine various criticisms questioning the relevancy of EF measures for the study of environmental justice between generations. We explore the difficulties raised by the physical—and highly aggregated—nature of EF measures, as well as problems related to the number, the possible non-existence, and the tastes of future generations. The extent to which postulates on nature’s regeneration and technological progress affect the significance of EF studies is also discussed. It is concluded that those criticisms, by identifying various weaknesses of EF measures for the study of intergenerational justice, point to several crucial refinements of existing EF-based analyses.

资源税改革中的经济行为和政府决策分析

资源是人类社会赖以存在的物质基础,也是社会经济发展的前提和必要条件,随着我国经济的快速发展,资源逐渐成为制约经济发展的"瓶颈",如何有效配置资源成为当前我国社会发展和经济转型的重要议题.国外经验证明可以通过资源税杠杆有效调节代际内和代际间的资源配置,提高资源使用效率.经济主体的行为和政府决策直接影响资源税改革的进程,本文构建世代交叠模型,通过资源税改革前后生产者和消费者的效用函数,分析并比较经济系统中主体不同济行为变化,在此基础上以资本和劳动动态变化来探讨资源税改革后的经济稳定性,并通过存在风险和政府声誉约束条件下的政府效用函数,分析和研究资源税改革中影响政府决策行为的主要因素,研究表明:资源税改革会对生产、消费产生影响,使经济主体的行为发生相应变化,但适当的资源税政策将保证经济稳定增长;同时改革成本、改革对产出的影响程度、政府风险态度和政府声誉等将影响政府决策行为,最后针对以上影响因素本文提出相应政策建议.     

Ethics and Environmental Attitudes With Implications for Economic Valuation

This paper tests the hypothesis that different ethical belief systems are unrelated to the attitude an individual takes towards the environment. More specifically, the neoclassical economic approach is seen to require a belief in utilitarianism while many individuals may operate on the basis of a deontological or rights-based approach to decision-making. The concern with this relationship arises from the use of the cost–benefit analysis approach to environmental policy and the specific application of the contingent valuation method. Evidence is found to support the view that environmentalists choose to operate on a rights-based approach which rejects the relative welfare arguments of economics and positively attributes compensation to future generations for environmental damages. This implies that the contingent valuation of environmental attributes will lead to values which are biased towards technocentric optimists and against the environmental movement. In terms of policy, environmental management on the basis of totalling economic values is liable to be undemocratic because of the systematic exclusion of a section of the general public.     

Effect of stage-specific vital rates on population growth rates and effective population sizes in an endangered iteroparous plant

Effective population size (N(e)) determines the strength of genetic drift and can influence the level of genetic diversity a population can maintain. Assessing how changes in demographic rates associated with environmental variables and management actions affect N(e) thus can be crucial to the conservation of endangered species. Calculation of N(e) through demographic models makes it possible to use elasticity analyses to study this issue. The elasticity of N(e) to a given vital rate is the proportional change in N(e) associated with a proportional increase in that vital rate. In addition, demographic models can be used to study N(e) and population growth rate (λ) simultaneously. Simultaneous examination is important because some vital rates differ diametrically in their associations with λ and N(e). For example, in some cases increasing these vital rates increases λ and decreases N(e). We used elasticity analysis to study the effect of stage-specific survival and flowering rates on N(e), annual effective population size (N(a)), and λ in seven populations of the endangered plant Austrian dragonhead (Dracocephalum austriacum). In populations with λ ≥ 1, the elasticities of N(e) and N(a) were similar to those of λ. Survival rates of adults were associated with greater elasticities than survival rates of juveniles, flowering rates, or fecundity. In populations with λ < 1, N(e) and N(a) exhibited greater elasticities to juvenile than to adult vital rates. These patterns are similar to those observed in other species with similar life histories. We did not observe contrasting effects of any vital rate on λ and N(e); thus, management actions that increase the λ of populations of Austrian dragonhead will not increase genetic drift. Our results show that elasticity analyses of N(e) and N(a) can complement elasticity analysis of λ. Moreover, such analyses do not require more data than standard matrix models of population dynamics.     

根据“闭路开环”原理制定人口政策

可持续发展的基本理论是在代际之间公平、均衡地分配自然资源。这一过程是一个闭路与开环的反馈控制系统。本文界定了三代人间的一个生物代际交叉期、一个社会代际交叉期和二个经济代际交叉期 ,设计了资源代际均衡分配管理模型 ,即 :代际年限长度 (δ)模型 ,且根据δ模型和闭路开环原理对人口政策进行了创新性分析     

环境相关浓度下的药物对大型蚤的多代慢性毒性

选择无脊椎动物大型蚤(Daphnia Magna)为供试水生生物,以磺胺甲恶唑、氧氟沙星和布洛芬作为目标污染物,在环境相关浓度下,对大型蚤进行6代慢性毒性研究.磺胺甲恶唑在0.8,8.0,80.0μg/L下,对大型蚤生殖和生长指标均没有发现明显的影响.200.0μg/L的氧氟沙星显著降低了F3(孤雌生殖第三代)和F4代的产卵数.900.0μg/L布洛芬明显延长了F3和F4代第一次产卵时间,并显著降低了F3、F4和F5代第一胎产卵数.在6代培养中,复合暴露M1处理(最低浓度药物混合物)没有表现明显效应,M2和M3处理在后面世代中明显延长产卵时间,降低产卵数量.相对于3种药物的单一暴露,复合暴露M2和M3处理增强了对大型蚤产卵时间和产卵数量的影响,提前表现出世代差异.2.0μg/L及20.0μg/L的氧氟沙星和9.0μg/L及90.0μg/L的布洛芬在连续6代的孤雌繁殖中没有发现明显的影响,200.0μg/L的氧氟沙星和900.0μg/L的布洛芬在前几代对大型蚤表现出一定的适应性或耐受性,而在后几代中,大型蚤出现产卵时间延后或产卵数量减少的现象,对大型蚤繁殖的影响表现出浓度依赖性和世代差异性.在目前检测环境浓度(MEC)下,3种药物单一污染和复合污染对大型蚤生态风险较低.