Sustainability and its relation to efficiency under uncertainty

Evaluating the long-run consequences of present actions, as in the context of sustainability, requires information about the actions’ outcomes and about future preferences that is often uncertain. We analyze a risk-based criterion of sustainability and a corresponding efficiency concept that cover these uncertainties. We derive several properties of these criteria and formally characterize the trade-off between sustainability and efficiency. Furthermore, we show that maximizing the probability of ex post efficiency under a sustainability constraint provides an interesting choice rule and that, for a special case, this rule is connected to portfolio theory. We are indebted to an anonymous referee whose comments helped substantially to improve the article.     

Probabilistic temperature change projections and energy system implications of greenhouse gas emission scenarios

This paper explores the implications for global average temperature change of a set of reference and mitigation scenarios in a probabilistic framework. First, we use published probability density functions for climate sensitivity to investigate the likelihood of achieving targets expressed as levels or rates of global average temperature change. We find, for example, that limiting warming to 3 C above pre-industrial levels with at least a medium likelihood requires cumulative emissions reductions on the order of 30-60% below one unmitigated reference scenario by 2100, while a more favorable baseline scenario requires no reductions at all to achieve this outcome with the same likelihood. We further conclude that the rate of temperature change may prove to be more difficult to control, especially if most of the mitigation effort is postponed until later in the century. Rate of change targets of 0.1–0.2 °C/decade are unlikely to be achieved by a target for the long-term level of climate change alone. Second, we quantify relationships between mitigation costs and the likelihood of achieving various targets and show how this depends strongly on the reference scenario. Third, we explore relationships between medium-term achievements and long-term climate change outcomes. Our results suggest that atmospheric concentrations and the share of zero-carbon energy in the middle of the 21st century are key indicators of the likelihood of meeting long-term climate change goals cost-effectively. They also suggest that interim targets could be an effective means of keeping long-term target options open. Our analysis shows that least-cost mitigation strategies for reaching low climate change targets include a wide portfolio of reduction measures. In particular, fundamental long-term structural changes in the energy system in these scenarios are a necessary but not sufficient condition to achieve high likelihoods for low temperature targets. The cost-effective portfolio of emissions reductions must also address demand-side measures and include mitigation options in the industry, agriculture, and the forest sector.     

Bio economic modeling for a sustainable management of biodiversity in agricultural lands

For several decades, significant changes in farmland biodiversity have been reported in Europe. Agriculture is a major driver of these modifications. Taking into account these environmental impacts, agriculture nowadays aims at a more sustainable way of producing which would reconcile its economic and ecological functions. The objective of this paper is to give insights into the impact of public policies on both conservation of biodiversity and farming production. We develop a macro-regional model combining community dynamics of 34 bird species impacted by agricultural land-uses and an economic decision model. The ecological dynamic model is calibrated with the STOC (French Breeding Bird Survey) and AGRESTE (French land-uses) databases while the economic model relies on the gross margins of the FADN (Farm Accountancy Data Network). We investigate the scenario based on subsidies and taxes. We show that simple economic instruments could be used to establish scenarios promoting economic performances and bird populations. It is pointed out how the sustainability of the policies is sensitive to the ecological and economic indicators used by the planner. The bio-economical analysis shows several solutions for the ecology-economy trade-off. These results suggest that many possibilities are available to develop multi-functional sustainable agriculture.     

Using Monte Carlo analysis to investigate the relationship between overconsumption and uncertain access to one's personal utility function

The failure of income and subjective well-being to correlate strongly beyond subsistence levels has been well documented. This is an important observation from an environmental perspective because it suggests that some excess consumption could be curbed without leading to a decline in subjective well-being. At the same time, there is evidence that access to one's internal utility function is imperfect, indicating that choices may approximate utility maximization but that the correspondence is unlikely to be exact. Here I use a Monte Carlo model to incorporate findings from hedonic psychology to investigate the question of how imperfect access to one's utility may lead to negatively affective overconsumption through asymmetries in how people are able to budget their time. According to the model, consumer debt leads to a compounding of this issue. Although it cannot return well-being to the ideal level, some hedonic costs of this overconsumption can be partially mitigated through required vacation in excess of what individuals would chose themselves in a fully functioning market, perhaps along the line of the European model.     

Diversity in foresight: Insights from the fostering of innovation ideas

Foresight activities have often provided support for objectives such as priority-setting, networking and consensual vision-building. In this paper, we draw upon complementary evolutionary perspectives and discuss these objectives from the viewpoint of diversity which may be vital in contexts characterized by technological discontinuities and high uncertainties. We also argue that although the scanning of weak signals has been widely advocated in such contexts, the solicitation of ideas for prospective innovations may provide more focused, action-oriented, and comparable reflections of future developments. For the analysis of such ideas, we develop a collaborative foresight method RPM Screening which consists of phases for the generation, revision, multi-criteria evaluation, and portfolio analysis of innovation ideas. We also report experiences from a pilot project where this method was employed to enhance the work of the Foresight Forum of the Ministry of Trade and Industry in Finland. Encouraging results from this project and other recent applications suggest that RPM Screening can be helpful in foresight processes and the development of shared research agendas.     

Resuscitating businessman risk: A rationale for familiarity-based portfolios

This paper studies two frequently observed portfolio behaviors that are seemingly inconsistent with rational portfolio choice. The first is the tendency of workers and entrepreneurs to hold their companyʼs stock. The second is the propensity of workers to limit their equity holdings through time. The explanation offered here for both of these behaviors lies in the option to switch jobs when oneʼs company does poorly. This is equivalent to holding put options on oneʼs own company stock and call options on the other companyʼs stock, where both options must be exercised at the same time. Given these initial undiversified implicit financial holdings, workers need to allocate a relatively large share of their regular financial assets to their own companyʼs stock and a relatively small share to the stock of their alternative employment simply to restore overall portfolio balance. Although this effect can only create some hedging demand for companyʼs stock, it is a factor of potentially major import for assessing the suitability of workersʼ financial decisions. I find that, under certain conditions, workers optimally hold almost 40% of their financial wealth in their companyʼs stock.     

联盟关系治理对创新项目组合成功的影响：来自IT行业的实证

项目组合作为企业重要的创新战略实施工具,目前在实践中被广泛应用。针对仅将企业内部因素作为创新项目组合成功前因的研究现状,从企业外部组织环境——联盟关系治理视角出发,基于197家IT企业的问卷调查数据,发现联盟关系治理对创新项目组合成功有显著正向影响,资源柔性和协调柔性在二者关系中起中介作用,项目关联度则分别调节了资源柔性、协调柔性与创新项目组合成功的关系。研究结果可为企业实现高绩效创新项目组合提供借鉴。     

Reconciling economic and biological modeling of migratory fish stocks: Optimal management of the Atlantic salmon fishery in the Baltic Sea

The paper puts forward a model of the Atlantic salmon fishery in the Baltic Sea that integrates the salient biological and economic characteristics of migratory fish stocks. Designed to be compatible with the framework used for actual stock assessments, the model accounts for age-structured population dynamics, the seasonal harvest and competing harvesting by commercial and recreational fishermen. It is parameterized for the Simojoki River stock. The socially optimal policy for maximizing discounted net benefits from the fishery within an uncertain environment is determined using a dynamic programming approach and numerical solution method. Our results indicate that substantial economic benefits could be realized under optimal management without compromising stock sustainability.     

Taxation and household portfolio composition: US evidence from the 1980s and 1990s

This paper explores the relationship between household marginal income tax rates, the set of financial assets that households own, and the portfolio shares accounted for by each of these assets. It analyzes data from the 1983, 1989, 1992, 1995, and 1998 Surveys of Consumer Finances and develops a new algorithm for imputing federal marginal tax rates to households in these surveys. The empirical findings suggest that marginal tax rates have important effects on asset allocation decisions. The probability that a household owns tax-advantaged assets, such as tax-exempt bonds or assets held in tax-deferred accounts, is positively related to its tax rate on ordinary income. In addition, the portfolio share invested in corporate stock, which is taxed less heavily than interest bearing assets, is increasing in the household’s ordinary income tax rate. Holdings of heavily taxed assets, such as interest-bearing accounts, decline as a share of wealth as a household’s marginal tax rate increases.     

To outsource or not to outsource in an integrated world

This paper investigates outsourcing decision under certainty and uncertainty. When the production activity can be fragmented into two or more processes, an integrated firm must be competitive in each of the fragmented processes. There are gains from outsourcing when factor prices differ between countries. When factor prices are not equalized internationally, a firm may outsource the process which uses its scarce source intensively. If the cost of outsourcing is lower in the foreign country, full outsourcing occurs under certainty. However, even if the outside supplier has a cost advantage, uncertainty in outsourcing cost ensures that partial outsourcing is optimal for risk-averse firms.     

Sustained output growth under uncertainty: A simple model with human capital

In a model where agents use their labour/education choice to adjust their consumption profile over time, I show that the impact of uncertainty on growth depends, critically, on agents’ attitudes towards risk, reflected by the coefficient of relative risk aversion. In this respect, the well known result from the literature on ‘saving under uncertainty’ can be extended into a broader context, whereby the intertemporal profile of consumption is determined via human capital accumulation rather than saving and physical capital investment.     

Individual account investment options and portfolio choice: Behavioral lessons from 401(k) plans

This paper examines how the menu of investment options made available to workers in defined contribution plans influences portfolio choice. Using unique panel data of 401(k) plans in the U.S., we present three principle findings. First, we show that the share of investment options in a particular asset class (i.e., company stock, equities, fixed income, and balanced funds) has a significant effect on aggregate participant portfolio allocations across these asset classes. Second, we document that the vast majority of the new funds added to 401(k) plans are high-cost actively-managed equity funds, as opposed to lower-cost equity index funds. Third, because the average share of assets invested in low-cost equity index funds declines with an increase in the number of options, average portfolio expenses increase and average portfolio performance is thus depressed. All of these findings are obtained from a panel data set, enabling us to control for heterogeneity in the investment preferences of workers across firms and across time.     

人民币汇率与股价动态相关性的研究——基于次贷危机前后的比较分析

本文基于2005年8月至2010年6月的月度数据,利用协整检验和向量误差修正模型研究了次贷危机发生前后人民币名义有效汇率与股票价格之间的联动关系。实证结果表明,次贷危机发生前中国股市与汇率之间存在正向的长期均衡关系,且两者之间在长期互为因果关系;在次贷危机发生后两者之间则是反向的长期均衡关系,股价波动在长期内是人民币名义有效汇率变动的单向Granger原因。最后本文基于人民币名义有效汇率的计算方法及其影响因素,利用资产组合平衡模型、国际贸易等相关理论对实证结果进行了分析。