气候变暖的第一影响因素及我国的应对

全球气候变暖已是人们逐渐接受的事实,由于大气中二氧化碳等气体含量的升高引起的温室效应是导致全球气温变暖的显著原因。经过统计分析发现,大气中碳含量的增加与全球森林面积减少、化石能源燃烧增加的碳排放高度相关,但年均0.4%增速的大气中的碳含量是与按年均0.2%速度递减的全球森林面积存在显著的统计上的因果关系,乱砍滥伐、开发耕地等导致的全球森林面积的减少是大气中二氧化碳含量增加的格兰杰因果关系原因,从而构成全球变暖的第一影响因素。二氧化碳排放量的增加一直比较平稳,年增速在2.2%左右,它与大气中的碳含量的增加虽然相关,但因果关系统计上并不显著,也不是其格兰杰因果关系原因,这一结论与IPCC的报告中二氧化碳排放量是全球变暖的主要原因的结论并不完全一致。据此,我们提出中国应对全球变暖时谨防陷入碳排放陷阱。     

全球气候变暖与节能的紧迫性

全球气候变暖已对人类生产与生活产生了很大的影响,文章利用统计实证的方法验证了二氧化碳气体排放与全球平均气温变化之间的关系,利用相关、回归与Granger因果关系检验,得出近年来二氧化碳排放量的增加是导致全球气候变暖的主要原因,而煤炭、石油、天然气消费量的增加又是引起全球二氧化碳排放量增加的主要原因。因此,节约能源,控制二氧化碳的排放,是应对全球气候变暖的必由之路。     

Policy Adoption Rules and Global Warming

Although there is widespread agreement about the dangers of global warming and the resulting need to cut down emissions, there does not seem to be general agreement about the exact form the policy should take or the timing of its adoption. Failure to adopt and implement policies against global warming reflects the complexity of the problem, the uncertainties of climate change and the cost of policy adoption. Issues associated with the interactions between uncertainties and irreversibilities in determining the timing of policy adoption are analyzed by using the methodology of optimal stopping rules. Optimal policy functions are derived for cooperative and noncooperative solutions, with differential game representation. Issues associated with the empirical application of the optimal policy rules are also considered.     

Games of Climate Change with International Trade

We analyse games of greenhouse gas emission reduction in which the emissions and the emission reduction costs of one country depend on other countries' emission abatement. In an analytically tractable model, we show that international trade effects on costs and emissions can either increase or decrease incentives to reduce emissions and to cooperate on emission abatement; in some specifications, optimal emission reduction is unaffected by trade. We therefore specify the model further, calibrating it to larger models that estimate the costs of emission reduction, trade effects, and impacts of climate change. If trade effects are driven by total emission reduction costs of other countries cooperation is slightly more difficult than in the case without trade effects. If trade effects are determined by relative emission reduction efforts in other countries, cooperation becomes easier. Carbon leakage does not affect our qualitative insights, although it does change the numbers.     

Efficient Climate Policy with Internationally Mobile Firms

A major concern in the design of an incomplete climate agreement is thatfirms that use fossil fuels intensively may respond to emission regulationsby relocating their plants from cooperating to non-cooperating countries.This paper analyses how the cooperating countries might deal with the issueof firm delocation through emission taxes, trade provisions and alocalisation subsidy to mobile firms. It is shown that firms should not beinduced to stay in the cooperating countries by lowering emission taxesbelow the Pigouvian tax rate. Incentives to stay should be given partlythrough trade provisions and partly through a localisation subsidy. A secondbest solution without localisation subsidies is also discussed. In thatcase, the efficient emission tax is lower than the Pigouvian tax rate.Finally, the paper discusses the implications of the first best and thesecond best policy regimes for the pattern of firm localisation.     

Future Inequality in CO2 Emissions and the Impact of Abatement Proposals

This paper analyzes future carbon emissions inequality using a group decomposition of the Gini index. Business-as-usual projections to the year 2100 for 135 countries show inequality in per capita emissions declines slowly. Next, the impact on emissions levels and inequality of the Kyoto Protocol and other abatement proposals for Annex II countries in 2010 are measured, with a focus on the gap-narrowing and reranking effects. Substantial reranking of per capita emissions between Annex II and non-Annex II countries will not occur unless the former reduce their emissions by at least 50% (versus 1990 levels) and the latter continue growing unabated.     

欧盟气候政策的利益导向及对中国的启示

自20世纪90年代以来,欧盟一直是全球气候谈判的主导者,其低碳技术领先全球,将世界各国尤其是美国、中国等排放大国纳入其主导的全球气候谈判体系符合欧盟三大布局主导下的核心战略目标.全球气候谈判的焦灼,迫使欧盟通过欧盟—拉美峰会、非加太—欧盟联合大会等平台,拉拢利益合作伙伴,以增加其主导气候谈判走向的砝码.欧盟气候政策的转变,削弱了气候谈判中以中国为代表的发展中国家谈判阵营的力量,使中国日益面临谈判伙伴减少,乃至被孤立的风险,增加了未来的谈判压力和难度.为此,中国要加紧对欧盟气候外交长期战略布局的研究,密切关注欧盟今后的气候外交政策动向,制定长期气候外交政策战略,同时加紧国内低碳转型的速度与力度.     

气候变化全球治理的处境、困境与路径

应对气候变化的全球治理无疑是当今世界最受关注的治理实践。与人们的期望相背,气候治理的实践一直都是并将在可见的将来都会是举步维艰的。之所以如此,是由气候治理的内在困境所决定的;因此,有效的治理路径只能是立足于现实困境之上的谨慎探索。     

气候政策的经济环境效应及其缓解措施的研究综述——兼谈对我国的启示

气候政策对一国经济和环境产生一定的效应,开放经济条件下还将对一国产业的国际竞争力产生影响。碳泄漏等问题使得气候政策的实际减排效果受到了质疑。气候政策实施过程中产生的这些问题都将严重影响气候政策的有效性。为使气候政策的有效性达到最优,很多学者研究了缓解气候政策负面效应的措施。本文对一些重要的气候政策的经济环境效应进行了理论总结,从竞争力效应、经济效应、环境效应和研究方法这四个方面综述了相关实证研究成果,分析了气候政策负面效应的缓解措施,以期为制定适合我国的气候政策提供借鉴。     

A Systematic Assessment of the Environmental Impacts of Transport Policy

This paper presents an integrated urbanpassenger transport model system for evaluatingthe impact of a large number of interrelatedpolicy instruments on urban travel behaviourand the environment. The model system has fourintegrated modules defining household locationand automobile choices, commuter workplace andcommuting travel choices, non-commuting travelactivity, and worker distributed workpractices. The demand model system, estimatedas a set of discrete and continuous choicemodels, is combined with a set of equilibratingcriteria in each of the location, automobileand commuting markets to predict overall demandfor passenger travel in various socio-economicsegments, automobile classes and geographiclocations. We illustrate the diversity of thesystem by applying the integrated system toPerth (Western Australia), in the context ofassessing their impacts on greenhouse gasemissions. The model system is embedded withina decision support system to make it anattractive suite of tools for practitioners.     

Endogenous Land use and the Ricardian Valuation of Climate Change

The Ricardian technique uses cross-sectional variation in the capitalized value of climate in land to infer the agricultural costs or benefits of dynamic climate change. While a practical approach for predicting the consequences of global warming with readily available data, it may yield biased results when land-use decisions depend on the climate attributes being valued and when land has unobserved attributes that differ with the use to which it is put. This paper illustrates the conditions under which such a bias will occur, describes an empirical model that corrects for it, and estimates that model with agricultural census data from Brazil. The approach, moreover, allows constraints on adjustment to be explicitly incorporated into the Ricardian framework, relaxing one of that technique’s most conspicuous assumptions. I would like to thank Patrick Bayer, Steven Berry, Robert Evenson, Michael Hanemann, Robert Mendelsohn, Bill Nordhaus, Kerry Smith, Karl Storchmann, two anonymous referees, and seminar participants at the University of California – Santa Barbara and the Research Triangle Institute for their useful insights and helpful comments. All remaining errors and omissions are my own. Fabiana Tito provided excellent research assistance, and Denisard Alves and Robert Evenson generously supplied the data.     

气候政策的时间不一致性问题研究

经验证据表明,很多国家都很难严格执行既定的气候政策。从理论上证明追求社会福利最大化的政府在经济剩余、政府税收收入和碳排放的负外部性等多重目标约束条件下,实施碳税政策时会产生时间不一致现象。结果表明,即使考虑到公共资金的边际成本,由于企业投资的不可逆转性和沉淀性,相对社会最优而言政府也会在事后降低碳税率,导致更多的能源消费和更多的碳排放。为克服时间不一致问题带来的效率损失,建议政府应建立独立的碳排放管制机构,对碳税政策做出可置信的承诺,改变电源结构,鼓励减排技术的投资,完善碳交易市场。     

技术政策需求分析模型及其在应对气候变化领域的应用

针对目前在技术政策的制定与实施方面我国与发达国家有较大差距的现状,引入技术生命周期理论,建立技术政策需求分析模型;并应用于应对气候变化领域:在综述国内外应对气候变化的技术政策实施现状的基础上,通过列表对比分析,最终得出我国应对气候变化的技术政策需求,以期为政策制定者提供决策参考,为我国应对气候变化目标顺利实现提供政策支持。     

Spatial and Temporal Efficiency in Climate Policy: Applications of FUND

FUND is an integrated assessment model of the interactions between climate and economy. Nine world regions emit greenhouse gases, and suffer damages from climate change. A number of greenhouse gas emission reduction policies are compared, including optimal and cost-effective strategies, strategies with early and late abatement, and strategies with and without international co-operation. The analyses confirm that co-operation matters, resulting in substantially lower costs or higher welfare. The real commitments of policy targets based on an absolute level (e.g., 1990 emissions) are hard to estimate because of the uncertainties in the baseline. Postponing action conflicts with minimising costs and maximising welfare, but so does sharp emission reduction at the short-term as proposed in the Kyoto Protocol.     

Uncertainty,Learning and International Environmental Policy Coordination

In this paper we construct a simple model of global warming which captures a number of key features of the global warming problem: (i) environmental damages are related to the stock of greenhouse gases in the atmosphere; (ii) the global commons nature of the problem means that these are strategic interactions between the emissions policies of the governments of individual nation states; (iii) there is uncertainty about the extent of the future damages that will be incurred by each country from any given level of concentration of greenhouse gases but there is the possibility that at a future date better information about the true extent of environmental damages may become available; an important aspect of the problem is the extent to which damages in different countries may be correlated. In the first part of the paper we consider a simple model with two symmetric countries and show that the value of perfect information is an increasing function of the correlation between damages in the two countries in both the cooperative and non-cooperative equilibria. However, while the value of perfect information is always non-negative in the cooperative equilibrium, in the non-cooperative equilibrium there is a critical value of the correlation coefficient below which the value of perfect information will be negative. In the second part of the paper we construct an empirical model of global warming distinguishing between OECD and non-OECD countries and show that in the non-cooperative equilibrium the value of perfect information for OECD countries is negative when the correlation coefficient between environmental damages for OECD and non-OECD countries is negative. The implications of these results for international agreements are discussed.     

Joint Implementation: Strategic Reactions and Possible Remedies

This paper investigates the promising proposal of Joint Implementation (JI) to mitigate greenhouse gas emissions. This was ultimately the only concrete outcome of the Conference on Climate Change in Berlin, albeit restricted to a pilot phase. The basic idea, given the public's awareness of global warming, sounds economically plausible: The industrialized countries, the only ones required to stabilize and lower carbon emissions, can search for cheaper reductions of greenhouse gas emissions in developing countries and economies in transition. However, this proposal leads to strategic reactions by developing countries reinforced by the fact that this cheating coincides with the interest of the industrialized country. In short, this proposal will lead to cheating (given asymmetric information) and will thus produce largely faked reductions in emissions. On the constructive side, an efficient mechanism retaining the spirit of JI is derived, which deters strategic reactions. This differs from a usual principal-agent problem through an additional hierarchical layer: a global authority (e.g. the Conference of Parties on Climate Change), an industrialized country and a developing country. The unavoidable loss that is even associated with an optimal scheme due to strategic, behavioural reality (the first best optimum is unattainable, except at the top) leads, of course, to much less glamorous predictions in emission reductions. Moreover, the implicit subsidization scheme focuses and favours on already 'efficient' partners.     

Optimal greenhouse gas emissions under various assessments of climate change ambiguity

The probabilities associated with global warming damage are likely to be continuously revised in the light of new information. Such revisions of probability are the defining characteristic of ambiguity, as opposed to risk. This paper examines how climate change ambiguity may affect optimal greenhouse gas emission strategies, via the decision maker's attitude towards anticipated changes of damage probabilities. Two conceptualizations of ambiguity are distinguished, according to the emphasis placed on the ambiguity of priors or on the ambiguity of news, respectively. It is shown that the way in which ambiguity is viewed and the attitude taken towards it have a substantial influence on the optimal emission trajectory.     

Global Warming and German Agriculture Impact Estimations Using a Restricted Profit Function

This study uses the concept of shadow prices formeasuring the impacts of climate change. By estimatinga restricted profit function rather than a cost or aproduction function the explanatory power of the modelis increased because of an endogenous outputstructure. Using low aggregated panel data on WesternGerman farmers, the results imply that the agricultural production process is significantly influenced by climate conditions. Simulation results using a 2 ×CO₂ climate scenario show positive impactsfor all regions in Germany. Interestingly, the spatialdistribution of the gains is indicating no advantagefor those regions, which currently suffer frominsufficient temperature. Finally, the importance ofan endogenous output structure is confirmed by thefinding that the desired product mix will drasticallychange.     

Development of a Fuzzy optimization model,supporting global warming decision-making

An increasing number of models have been developed to support global warming response policies. The model constructors are facing a lot of uncertainties which limit the evidence of these models. The support of climate policy decision-making is only possible in a semi-quantitative way, as presented by aFuzzy model. The model design is based on an optimization approach, integrated in a bounded risk decision-making framework. Given some regional emission-related and impact-related restrictions, optimal emission paths can be calculated. The focus is not only on carbon dioxide but on other greenhouse gases too. In the paper, the components of the model will be described. Cost coefficients, emission boundaries and impact boundaries are represented asFuzzy parameters. TheFuzzy model will be transformed into a computational one by using an approach of Rommelfanger. In the second part, some problems of applying the model to computations will be discussed. This includes discussions on the data situation and the presentation, as well as interpretation of results of sensitivity analyses. The advantage of theFuzzy approach is that the requirements regarding data precision are not so strong. Hence, the effort for data acquisition can be reduced and computations can be started earlier.     

Long-Run Implications for Developing Countries of Joint Implementation of Greenhouse Gas Mitigation

Joint Implementation (JI) calls for cooperation between industrialized and developing countries in the mitigation of greenhouse gas (GHG) emissions. However, a major concern of potential host countries is that, if they utilize their low-cost options for JI now, they will be left with only high cost options in the future, thereby penalizing them at a time when they may be obligated to mitigate GHGs themselves. This paper formalizes this hypothesis by utilizing an optimal control framework analogous to the Hotelling model of non-renewable resource extraction. The results are that cumulative abatement effects can impose costs on the future, but that they can be offset by technological change, market power, or compensation.