Uncertainty and Climate Change

Uncertainty is pervasive in analysis of climatechange. How should economists allow for this? And how have they allowed for it? This paperreviews both of these questions.     

Restoration of a Depleted Transboundary Fishery Subject to Climate Change: A Dynamic Investment Under Uncertainty with Information Updates

Environmental and Resource Economics - We model the evolution of a trans-boundary marine fishery, which is based on the harvesting of a single “highly-migratory” stock and is beginning...     

Optimal Policy under Uncertainty and Learning about Climate Change: A Stochastic Dominance Approach

Global climate change presents a classic problem of decision making under uncertainty with learning. We provide stochastic dominance theorems that provide new insights into when abatement and investment into low carbon technology should increase in risk. We show that R&D into low-carbon technologies and near-term abatement are in some sense opposites in terms of risk. Abatement provides insurance against the possibility of major catastrophes; R&D provides insurance against the possibility that climate change is marginally worse than average. We extend our results to the comparative statics of learning.     

Risk Aversion, Intergenerational Equity and Climate Change

The paper investigates a climate-economy model with an iso-elastic welfare function in which one parameter measures relative risk-aversion and a distinct parameter measures resistance to intertemporal substitution.We show both theoretically and numerically that climate policy responds differently to variations in the two parameters. In particular, we show that higher but lower leads to increase emissions control. We also argue that climate-economy models based on intertemporal expected utility maximization, i.e. models where = , may misinterpret the sensitivity of the climate policy to risk-aversion.     

Valuation and Management of Fishing Resources Under Price Uncertainty

The traditional expected-net-present-value methods cannot properly capture the management flexibility and strategic value aspects of a fishery, and may understate its value. Instead, this paper develops a Real Options model to conceptualize and evaluate fishery exploitation flexibility. Specifically, general models to value the opportunity to either exploit or invest in a fishery are presented. They suffice to determine not only these values, but also the optimal policy for opening, closing, delaying and setting its harvest rate. The sustainable case in which the harvest rate equals the natural net growth function is also considered. Concerning the exploitation decision, it is found that, as could be expected, the higher the resource price the higher the value of this opportunity in both models (general and sustainable). However, the resource stock affects both models differently. As to the investment opportunity, its value is always lower than the exploitation opportunity because of investment costs. Finally, numerical simulations are run in order to illustrate the nature of the solution. Sensitivity analysis concerning the influence of the tax rate, convenience yield, risk-free interest rate and price volatility on the value of the fishery is also reported. Earlier versions of this paper have benefited from conference participants at the Young Economists Conference 2000 (Oxford University), Tenth Biennial Conference of the International Institute of Fisheries Economics and Trade (Oregon State University), XXV Simposio de Análisis Económico (Universidad Autónoma de Barcelona, Spain) and Seminar at the Dpt. Fundamentos del Análisis Económico (Universidad del País Vasco, Spain). We especially thank Prof. Ian Bateman and two anonymous referees whose insightful comments have enabled us to eliminate several errors and to improve the presentation. Murillas gratefully acknowledges doctoral fellowship from Ministerio de Educación y Ciencia (AP96), and financial support from the Xunta de Galicia (PGIDT01PXI30004PR) and from the Ministerio de Ciencia y Teconología (SEC 2001-3700). The usual disclaimer applies.     

On the Uncertainty About the Total Economic Impact of Climate Change

This paper uses a vote-counting procedure to estimate the probability density function of the total economic impact as a parabolic function of global warming. There is a wide range of uncertainty about the impact of climate change up to 3°C, and the information becomes progressively more diffuse beyond that. Warming greater than 3°C most likely has net negative impacts, and warming greater than 7°C may lead to a total welfare loss. The expected value of the social cost of carbon is about $29/tC in 2015 and rises at roughly 2% per year.     

An Experimental Study of Risk Aversion in Decision-making Under Uncertainty

This paper presents the findings of an experimental study of risk aversion in decision making under uncertainty. When presented with a series of gambles, subjects determined the certainty-equivalent wealth of each gamble. Risk aversion was measured by the Markowitz risk premium of the decision. The fixed effects regression model indicates the significant influence of the first three moments of a probability distribution in determining the risk premium. These results lend support to the rules of mean-variance and third-degree stochastic dominance. The extent of influence is also affected by the individual’s age, but not by gender, wealth or schooling.     

Impact of Climate Change and International Prices Uncertainty on the Sudanese Sorghum Market: A Stochastic Approach

This paper simulates the possible sorghum price change and the related probability of occurrence under different rainfall scenarios and in a context of price uncertainty in international markets. The empirical investigation is based on the stochastic approach. Results indicate an expected increase in sorghum price due to a high level of uncertainty in precipitation and in international market price, the most change likely produced by the latter, and the need to alter the agricultural view of policy making to include a market perspective.     

气候变化的经济分析

气候变化在经济学上提出了独一无二的挑战,这是迄今为止范围最大、规模最大的市场失灵现象。文章探讨了经济发展与气候变化之间的互动关系：从市场失灵的角度切入,通过阐述气候变化对经济发展的影响,探讨政府和企业对气候变化所产生的影响做出的反应,从而提出中国应对这种“市场失灵”现象应采取的措施。     

Climate Policy Under Fat-Tailed Risk: An Application of Dice

Uncertainty plays a significant role in evaluating climate policy, and fat-tailed uncertainty may dominate policy advice. Should we make our utmost effort to prevent the arbitrarily large impacts of climate change under deep uncertainty? In order to answer to this question, we propose a new way of investigating the impact of (fat-tailed) uncertainty on optimal climate policy: the curvature of the optimal carbon tax against the uncertainty. We find that the optimal carbon tax increases as the uncertainty about climate sensitivity increases, but it does not accelerate as implied by Weitzman’s Dismal Theorem. We find the same result in a wide variety of sensitivity analyses. These results emphasize the importance of balancing the costs of climate change against its benefits, also under deep uncertainty.     

气候变化伦理研究评述

气候变化日益成为国际社会的一个热门话题。关于对气候变化问题的国际辩论经历了一个从科学、经济学和政治学争论到伦理争论的历程。气候变化是一个典型的＂全球伦理问题＂,气候变化伦理问题的关键是利益冲突。要解决＂缓解＂和＂适应＂气候变化、碳排量分配的合理性、发展中国家的发展空间及其补偿等一系列问题,必须要对气候公正原则、共同而有区别的责任等问题获得共识。     

Weight Factors in Cost-Benefit Analysis of Climate Change

Equity considerations may justify the use of weight factors when estimating the costs of climate change. This paper reviews different weight factors that have been used in the climate economics literature. Based on a simple model, it is shown that although the different weight factors imply substantially different cost-damage estimates, they actually yield the same optimal emission reductions. This paradox is explained by the fact that some of the approaches require that also the abatement costs are weighted – and this offsets the effect of the diverging cost-damage estimates. The model is then used to analyse the importance weighting may have on the overall cost-benefit analysis. At present, when most of the global emissions of (fossil) CO2 originate from the industrialised countries, the global optimal emissions are considerably lower if costs are weighted. However, the more the emissions in developing countries grow, the less important becomes the introduction of weight factors in cost-benefit analysis of climate change for the global emission reductions, in the model developed here. On a regional level, the introduction of weight factors continues to play an important role, implying substantially lower emissions in the rich region and slightly higher (!) in the poor.     

知识经济时代企业经营方式与营销渠道的变革

知识经济是建立在知识和信息的生产、分配和使用基础之上的经济形态。在知识经济条件下,企业经营方式和营销渠道出现了新的变化,把握这些新变化并改进我国企业经营的渠道策略,有利于企业实现"走出去"战略目标。     

气候变化的地球环境解读与不良后果分析

地球相对适宜的平均温度为15℃,这种动态平衡显然已被打破,全球加速变暖已是不争的事实.在影响地球环境变迁的天-地-人三大因素中,天和地的作用是客观的、决定性的、不可逆的;生物作用特别是人的作用大多是主观的、非常重要的、负有人为责任的.气候变暖的负面影响,不仅使极端天气气候事件频繁发生,使局部地区甚至整个生物圈结构和功能失衡,导致全球环境进一步恶化,而且在经济社会层面各方借机争夺未来在能源发展和经济竞争中的优势地位,势必引发全球公共资源的新一轮利用和分配问题而产生的冲突,威胁和与平安全.看来,限制CO2等温室气体排放、应对气候变化的国际主流的努力,在技术上是可行的,但在政治或经济上是否可行,需要展开进一步深入的国际磋商与务实合作实践.     

财务管理在信息时代的变革

信息技术和信息产业正以惊人的速度在改变人类的生活方式。信息革命给传统产业创造了新的发展机遇,但同时也给企业的经营运作模式、思想观念等带来深远的冲击。要适应现代社会的需要,应更新财务管理观念,建立并完善财务管理信息系统,健全财务信息安全防范体系。     

经济政策不确定性与系统性金融风险的跨市场传染——基于非线性网络关联的研究

本文构建"全球金融市场与经济政策不确定性"的非线性关联网络,对全球19个主要国家(地区)的经济政策不确定性(EPU)与系统性金融风险传染关系展开研究。结果表明,股票市场是风险的主要输出方,而外汇市场则是风险的主要接受者,两者之间存在非对称传染效应。分样本研究发现,危机期间风险传染更加明显,且EPU在风险传染中发挥着重要作用;同时,股票市场是风险的源头,对外汇和EPU具有较强的溢出效应。近四年的分析发现,风险传染沿着"股票市场→经济政策不确定性→外汇市场"这一途径扩散开来。进一步的分析发现,境外金融市场会对中国大陆金融市场产生显著的风险传染,中国香港金融市场则容易遭受外部冲击。此外,美国资本市场会对全球造成明显的风险冲击,全球EPU(尤其美国EPU)是引发全球金融市场震荡的重要因素。     

产业集群萌芽阶段的衰退风险研究

文章将产业集群的生命周期划分为萌芽阶段、成长阶段、稳定阶段和创新发展阶段,与集群成长的其他阶段相比,萌芽阶段由于"非合作博弈"等现象的普遍存在,集群面临早衰的风险最大.在分析萌芽阶段衰退风险表现及影响因素的基础上,构建了LQ计量模型来识别产业集群萌芽阶段的衰退风险.