题目：1. Increasing Returns to Scale and the Incentives to Join a Climate Treaty
      2. On the Equivalence of the Nash Bargaining Solution and the Lindahl Equilibrium in Models of Environmental Externalities
主讲人：杨自力 教授（纽约州立大学宾汉顿经济学教授、12BET兼职教授、耶鲁大学经济学博士）
时间：2016年1月25日（周一）上午9:30
地点：主楼六层
主讲人介绍：
    杨自力，主要从事资源与环境经济学、能源经济学、经济建模、应用博弈论、中国经济等研究工作。同耶鲁大学教授William D. Nordhaus合作，发展建立了在世界范围内最具影响力的气候变化综合评估模型（RICE模型），并发表在American Economic Review等重要期刊。RICE模型及其衍生的多个模型在联合国政府间气候变化专门委员会（IPCC）历次报告中被广泛使用。杨教授独立发展了将博弈论数值解的概念和算法与气候经济综合评估模型相结合的研究方法，在此开拓性领域居国际领先地位；是世界上第一个将非合作博弈解以及合作博弈解引入大型综合评估模型的学者；是上世纪90年代麻省理工学院能源实验室EPPA模型的最主要建模者。
内容介绍：
报告1：Increasing returns to scale (IRS) phenomena are broadly present in international economic relationship. This paper studies the connection between IRS in energy-intensive industries and the attitude towards global climate negotiation. In a model of detrimental externality, the proposition proven states that if some agents maintain IRS with respect to the good generating externality (such as GHG emission), their optimal position in the efficient externality provision can be very close to their inefficient non-cooperative Nash equilibrium position. Numerical simulations validate the conclusion of the proposition. The conclusion explains some fundamental difficulties in international climate negotiations. Finally, the policy implication of IRS on climate negotiation is also discussed.

报告2：The Nash bargaining solution and the Lindahl equilibrium are two important solution concepts in an economy with externality. In this paper, it is proved that the Nash bargaining solution that uses the payoffs of non-cooperative Nash equilibrium as the status quo point is the Lindahl equilibrium without transfers of the problem. Furthermore, the Lindahl equilibrium without transfer can be expressed as the social optimum with the welfare weights set at the cost-sharing ratio retrieved from the Nash bargaining solution. The equivalence connection between this specific Nash bargaining solution and the Lindahl equilibrium without transfers has broad applications in environmental problems. The simulations conducted in the RICE model verify such equivalence relationship and demonstrate the feasibility of its applications in environmental issues. Finally, algorithmic scheme of applying the Nash bargaining solution and the Lindahl equilibrium in environmental modeling are provided in this paper.


（承办：能源与环境政策研究中心，科研与学术交流中心）