Green (or environmental) economics—the subject of this book—is a growing branch of economics that deals with the environment, pollution, and climate change. Mainstream economics is concerned primarily with the operation of the market economy, while green economics focuses on its spillovers (a.k.a. externalities) with adverse impacts outside the marketplace, for example, on the health of humans and other life forms, on ecosystems and on the climate. Most economists accept the importance of these externalities but consider them to be market failures to be addressed by changing the prices associated with pollutants (e.g., putting a tax on CO₂ emissions) and other harmful externalities. Any intervention should be optimally designed (i.e., its marginal benefits should be equal to its marginal cost) to achieve an “optimum pollution level.” Nordhaus—winner of a Nobel prize—is comfortable with this general approach but also recognizes the need to pay attention to critiques of the market approach and realizes that cost-effective analysis is not straightforward. How should the needs of future generations be taken into account? How does one value environmental quality and environmental services? How much should be spent to prevent the extinction of an animal species? Sustainability is the widely accepted overall objective but there is no agreement on a definition of this term. Economists argue that we should sustain the ability of future generations to have a good standard of living, even if that comes at the cost of consuming natural capital. In contrast, environmentalists want to preserve our natural environment and even reverse the damage done in the past. Clearly, environmental economist who are charged with estimating the costs and benefits of taxes and regulations have a difficult job. But even if economists could come to an agreement, there is a second major obstacle: Only governments can implement measures needed to protect public goods (e.g., by imposing taxes) and such governmental action requires the consent of the voters. In an ideal world, scientists would identify environmental problems and economists would produce accurate cost-benefit calculations to design optimal remedies. Next comes the need to persuade the general public by providing clear information and, if needed, “nudges” designed by behavioral economists. The informed voters would then elect representatives to congress/parliament, who would put into effect the measures recommended by the scientist, ignoring the pleas of lobbyists. In negotiations on global environmental issues such as greenhouse gas emissions, national representatives would protect the common interests of all humanity rather than focus on the national interest. What could possibly go wrong? The great value of this important book is that it combines a succinct and accessible overview of environmental economics with a thoughtful discussion of the wide range of political, institutional, and behavioral obstacles that stand in the way of optimal environmental outcomes. —J.B.

绿色（或环境）经济学——本书的主题——是处理环境、污染和气候变化的经济学的一个不断发展的分支。主流经济学主要关注市场经济的运作，而​​绿色经济学则关注其在市场之外产生不利影响的溢出效应（即外部性），例如人类和其他生命形式的健康、生态系统和气候. 大多数经济学家接受这些外部性的重要性，但认为它们是市场失灵，需要通过改变与污染物相关的价格来解决（例如，对 CO _2征税）排放）和其他有害的外部性。任何干预措施都应进行优化设计（即其边际收益应等于其边际成本）以达到“最佳污染水平”。诺德豪斯——诺贝尔奖获得者——对这种一般方法感到满意，但也认识到需要关注对市场方法的批评，并意识到成本效益分析并不简单。应如何考虑子孙后代的需求？如何评价环境质量和环境服务？应该花多少钱来防止一个动物物种的灭绝？可持续性是被广泛接受的总体目标，但对该术语的定义没有达成一致意见。经济学家认为，我们应该维持后代拥有良好生活水平的能力，即使这是以消耗自然资本为代价的。相比之下，环保主义者希望保护我们的自然环境，甚至扭转过去造成的破坏。显然，负责估计税收和法规的成本和收益的环境经济学家有一项艰巨的工作。但即使经济学家能够达成协议，还有第二个主要障碍：只有政府才能实施保护公共产品所需的措施（例如，通过征税），而这种政府行动需要选民的同意。在理想的世界中，科学家会发现环境问题，经济学家会进行准确的成本效益计算以设计最佳补救措施。接下来需要通过提供明确的信息来说服公众，如果需要，行为经济学家设计的“助推器”。然后，知情的选民将选举代表参加国会/议会，他们将实施科学家建议的措施，无视游说者的请求。在温室气体排放等全球环境问题的谈判中，国家代表将保护全人类的共同利益，而不是专注于国家利益。什么可能出错？这本重要著作的巨大价值在于，它结合了对环境经济学的简洁易懂的概述和对阻碍最佳环境结果的广泛政治、制度和行为障碍的深思熟虑的讨论。—JB 谁会执行科学家建议的措施，无视游说者的请求。在温室气体排放等全球环境问题的谈判中，国家代表将保护全人类的共同利益，而不是专注于国家利益。什么可能出错？这本重要著作的巨大价值在于，它结合了对环境经济学的简洁易懂的概述和对阻碍最佳环境结果的广泛政治、制度和行为障碍的深思熟虑的讨论。—JB 谁会执行科学家建议的措施，无视游说者的请求。在温室气体排放等全球环境问题的谈判中，国家代表将保护全人类的共同利益，而不是专注于国家利益。什么可能出错？这本重要著作的巨大价值在于，它结合了对环境经济学的简洁易懂的概述和对阻碍最佳环境结果的广泛政治、制度和行为障碍的深思熟虑的讨论。—JB 国家代表将保护全人类的共同利益，而不是专注于国家利益。什么可能出错？这本重要著作的巨大价值在于，它结合了对环境经济学的简洁易懂的概述，以及对阻碍最佳环境结果的广泛政治、制度和行为障碍的深思熟虑的讨论。—JB 国家代表将保护全人类的共同利益，而不是专注于国家利益。什么可能出错？这本重要著作的巨大价值在于，它结合了对环境经济学的简洁易懂的概述，以及对阻碍最佳环境结果的广泛政治、制度和行为障碍的深思熟虑的讨论。—JB