气候法案的理论分析.doc

Wonky Talk about Carbon Taxes qianlaoda译I appreciate David Leonhardts kind words about my recent Times column on the problems with giving away, rather than auctioning, carbon allowances. I thought it might be useful to explain a bit more some of the economics behind what he calls my Rorschach test. Here is the more wonky way of putting some of the arguments.感谢David Leonhardt。我最新的纽约时报专栏上讨论了“二氧化碳配额”的分配（而非拍卖）的问题，他给予了善意的评价1。我认为，就他所说的“曼昆的罗尔沙赫氏测试”背后的经济学，给予多一点的解释，可能还是有意义的。下面是一些比较书生气的解释，来说明我的一些观点。We can think of the typical household as having to make two decisions. First, the household decides how much to work and consume. This is the standard consumption-leisure tradeoff. Second, the household decides how to allocate consumption between carbon-intensive products and less carbon-intensive products.我们可以设想，典型的家庭必须进行两个选择。第一个选择是：家庭必须决定工作量和消费量。这是标准的消费-闲暇权衡模型。第二个选择是：家庭要决定在二氧化碳的关联产品和非二氧化碳关联的产品上的消费分配。Mathematically, we might write utility as数学上，我们可以将效用记为如下形式：U = u(C) + v(L)where C is consumption and L is leisure. Consumption is a composite of carbon-intensive consumption C1 and less carbon-intensive consumption C2, which we can write as其中，C为消费量，L为闲暇量。消费包括“二氧化碳关联产品”的消费量C1 和“非二氧化碳关联产品”的消费量C2, 因此，消费就可以写为：C=F(C1,C2).There are two margins of adjustment: between C and L, and between C1 and C2.存在两个边际调整：C和L之间，以及C1和C2之间.We start in a situation in which each of these margins of adjustment is distorted. Because earnings are taxed via income and payroll taxes, people have too little incentive to work and consume. In addition, because there is a negative externality associated with carbon, people have too little incentive to move their consumption basket toward less carbon-intensive products. In other words, the relative price of consumption compared to leisure is too high, and the relative price of carbon consumption compared to noncarbon consumption is too low.我们的初始状态是：这两个边际调整，每一个都是扭曲的。因为人们的所得有两种税收：收入税和工资税，所以，他的工作激励和消费激励是非常小的。同时，因为存在“二氧化碳的负外部性”，所以，人们的消费转为“非二氧化碳关联产品”的激励，也非常小。换言之，消费相对于闲暇的相对价格，是非常高的；而且，“二氧化碳产品”的消费相对于“非二氧化碳产品”的消费的相对价格，也是非常低的。The trick is how to fix the second distortion without making the first one worse. A tax on carbon with the revenues used to cut income taxes does that. Everyone who thinks there are negative carbon externalities should agree that is the efficient policy.关键在于：如何能固定第二种扭曲，而不使得第一种变得更差。对二氧化碳征税，并将税收收入用于削减收入税，就可以实现这个目标。每一个认为“存在二氧化碳的负外部性”的人，都应该会知道：这就是有效的政策。A tax on carbon with the revenue squandered via lump-sum handouts to powerful special interests, however, fixes the second distortion but makes the first one worse. The good thing about this policy is that it raises the price of carbon-intensive consumption relative to less carbon-intensive consumption. The bad thing about it is that it also raises the price of consumption relative to leisurein other words, it depresses the real wage. The basic problem is that a new tax on carbon-intensive products C1 is also an additional tax on consumption C, unless there is some other offsetting tax change.然而，对二氧化碳征税，但是，税收收入却通过一次性地将配额转移给“有权势的特殊利益群体”而分散，就是“固定了第二种扭曲”却使得第一种扭曲变得更糟糕。这种政策的好处在于：它提高了“二氧化碳关联产品”消费相对于“非二氧化碳关联产品”消费的价格。它的坏处在于：它也提高了消费相对于闲暇的价格换言之，它压抑了真实工资。基本的问题就是：除非存在一种抵偿性的税收变化，对二氧化碳产品C1的新增税收，也是对总消费C的新增税收。This is where the Rorschach test comes in. A carbon tax without a compensating income tax cut makes one problem better and one worse. The question then is which problem is bigger. I dont think there is a consensus among economists on this last question. That is why reasonable people can disagree about the bill being debated in Congress.现在，罗氏测试就出现了。对二氧化碳征税，却不进行补偿性的收入税的消减，使得一种问题变好，又使另一种问题变差。这时的问题就是：哪一个问题更加大一些？我认为，在这个新问题上，经济学家之间并不存在共识。这就是理性的人们并不同意正在国会讨论的那个法案的原因。But there is a consensus, more or less, that we could fix one margin of adjustment without distorting the other margin more. But that requires a cut in income or payroll taxes to be a key part of the environmental policy. 但是，差不多还是有一个共识的。即：我们可以固定一个边际调整，而不使另一个边际调整更加扭曲。但是，这就需要对收入税或工资税进行削减，这就是环境政策的核心部分了。注释：1. 关于善意评价。即：无论你自己位于哪个阵营，我也要推荐曼昆的专栏。他的模型使人能理解复杂的