1、 外文翻译 原文 Trade， Growth， and the Environment Material Source: Journal of Economic Literature， Vol.42,No.1,(Mar， 2004)pp.7-71 Author: Brian R. Copeland and M. Scott Taylor 3. Trade Liberalization and the Environment We now turn to the impact of international trade on the environment. We draw the usual
2、 distinction between trade and growth: trade liberalization changes relative goods prices by opening up the economy to increased foreign competition, while growth increases endowments or improves technology at given external prices. While this distinction is clear, it may not always be accurate. The
3、re is empirical evidence that trade liberalization also stimulates economic growth, and at a theoretical level, trade can alter the rate of growth if it spurs innovation or factor accumulation. In addition, trade may also pave the way for labor and capital mobility and technology transfer. Hence, tr
4、ade can set in motion forces that shift the production. We first examine the effects of trade on the environment in a small open economy facing fixed world prices to emphasize three major points. First, the effect of trade liberalization on the environment depends on a countrys comparative advantage
5、, which in turn depends on country characteristics. There is no reason to expect trade to have the same effect on all countries. Second, the effects of trade on the environment depend on whether environmental policy is rigid or instead responsive to changes brought about by trade. When policy is rig
6、id we will show that outcomes depend on the type of environmental policy instruments used by regulators. Finally, the welfare effects of trade liberalization are sensitive to both a countrys comparative advantage and the flexibility of its policy regime. Trade Frictions. For modeling purposes, we ne
7、ed to be specific about the trade barriers that are being reduced. Some trade barriers (such as tariffs) generate revenue; others, such as distance, generate productive activities such as transportation to overcome them; and yet others, such as bureaucratic delays and regulations simply create tradi
8、ng costs. We dont want to focus on the details of trade policy, but simply capture the effects of increased opportunities to trade. To do so we assume there are some trade frictions between countries, which we capture by adopting an “iceberg“ model of trade costs. With iceberg costs, an importer who
9、 wants to receive one unit of X from the foreign country has to ship 1+ units because is lost in transport. Trade therefore consumes real resources, and the magnitude of trade frictions increase as rises. Trading costs drive a wedge between the domestic and foreign price of a good. As before let p d
10、enote the world price of X, then the domestic price of X for an importing country is: (24) Conversely, if Home exports X, then to deliver a unit of X to a foreign market (where the price is p), a home exporter must send 1+ units, which are acquired locally at the domestic price . Hence the domestic
11、price is lower than the foreign price: (25) It is convenient for us to use to refer to the domestic price, but the reader should keep in mind that whether this price is above or below the world price depends on the countrys comparative advantage. 3.1 Rigid Policy Fixed Emission Intensities. The effe
12、cts of trade liberalization on the environment depend on the environmental policy regime. We start with a simple case where government policy holds the emission intensity of production fixed. This scenario is instructive because it simplifies the analysis by ruling out a technique effect, and may be
13、 a realistic approximation of policy in many countries (at least in the short run) because much pollution regulation tends to target emissions intensities, rather than overall emissions. This approach also allows for the special case of no pollution regulation. Consider a country importing the dirty
14、 good X. The domestic price is initially above the world price, and as trade barriers fall, the domestic relative price of X falls. As with growth, we can decompose the effects of trade liberalization into scale, composition and technique effects. This is illustrated in figure 3. The production fron
15、tier (for a given emission intensity) is depicted in the top half of the diagram, and pollution is measured as a function of X in the bottom half. Starting with producer price at point A, a trade liberalization reduces the domestic producer price of X to Production moves from point A to C, and pollu
16、tion falls from zo to Z2. If we measure the scale of output at world prices p, then (hypothetical) movements along the dashed line through AB (with slope p) keep the scale of the economy constant. This allows us to decompose the change in pollution into a composition effect (A to B) which lowers pol
17、lution from zo to z1, and a scale effect (B to C) which raises pollution from z1 to z2. There is no technique effect in this example by assumption. The scale effect is positive and tends to increase pollution. Trade increases production efficiency (measured at world prices), and this leads to more o
18、utput, and hence more pollution. The composition effect is negative, because protection is being removed from the polluting good, inducing producers to shift towards the clean good. In our simple model where only one good pollutes, the composition effect always dominates the scale effect, because tr
19、ade liberalization has an unambiguous effect on the output of the polluting good. If the economy has a comparative advantage in clean goods, as in this example, trade is good for the environment. If instead home exports X, then trade liberalization raises . Producers shift along the production front
20、ier towards the dirty good. This both increases the scale of production and shifts the composition of output towards the polluting good: both the scale and composition effects reinforce each other and lead to an increase in pollution. In summary, with fixed emission intensities, the composition effe
21、ct is critical in determining the effects of trade liberalization. Moreover, the sign of the composition effect is ultimately determined by a countrys comparative advantage. If a country has a comparative advantage in clean industries, then clean industries expand with trade; and conversely, if it h
22、as a comparative advantage in polluting industries, then dirty industries expand with trade. Fixed Emission Permits. Now suppose the government uses a marketable emission permit system to regulate pollution, and that it does not adjust the supply of permits in response to changes in the trade regime
23、. Earlier, we noted the equivalence of permit and tax systems as a method of implementing the first best. But if we hold policy instruments fixed in the face of shocks to the economy, this equivalence breaks down. 译文 贸易增长与环境 资料来源 : 经济文学期刊， 42 卷 .第一章（ 2004.5） 7-71 页 作者： Brian R. Copeland and M. Scott
24、 Taylor 3贸易自由化和环境 现在我们来看国际贸易对环境因素的影响。我们用一般贸易理论来区分贸易和发展；也就是说，贸易自由化的变化是由于开放经济改变了商品的价格进而增加了国外竞争力，同时增加了捐助或提升了技术的外部价格。 虽然这区别非常明显，但不可能很准确。有证据说明贸易自由化也刺激了经济增长；从理论层面说，贸易自由化刺激了创新或增加了要 素积累改变了贸易的增长速度。再者，贸易也可以铺平道路或回归于劳动、资本流动和技术转让。因此，贸易也能产生力量推动生产边界转移。 我们首先研究在小型开放经济里贸易对环境的影响。面临的固定价格强调了三个主要观点。第一，贸易自由化对环境的影响根据一个国家的比
25、较优势，而这也取决于国家的特征。没有理由去期待所有国家会产生相同的环境影响。第二，贸易的环境效应取决于政策是否僵化或者 引起的新的贸易体制和经济情况 能否适应经济环境的变化。最后，贸易自由化的福利对一个国家的比较优势和它的政策、政权影响都很敏感。 我们从一个 2 区 模型来了解两个主要的假设，与国家特征相联系从而得出环保成果：污染避难所的假说和要素禀赋论的假说。这就规定的审查阶段我们回顾实证的工作。 贸易摩擦。我们需要具体列出在我们的模型当中正在被减少的贸易壁垒这是建模的目的。有很多不同类型的贸易壁垒。一些（如关税）产生收入；其他国家，像距离产生的生产活动，例如交通运输，必须克服它们；另一些，
26、如官僚主义的拖延和法规简单的创造了贸易成本。就这一点而言，我们不想集中关注于贸易政策的细节，而以一种简单的方式去抓住贸易影响带来的更多机会。为此，我们假设国家与国家之间有些贸易摩擦 。我们采用了贸易成本的“冰山”模型。 那就是 ， 一个进口商想要从外国收到一个单位的 X 必须装运 单位因为消失在运输中。贸易因此消耗真正的资源，贸易摩擦 会以 倍的增加。 交易成本驱使国内和国外价格在一个协调的边缘。让 P 代表世界价格 X，然后国内价格为 X 进口国就是： 反之，如果国内出口 ，然后出口提供一单位 去国外市场 国外市场价格为 P),国内出口商必须发出 1+ 单位，在当地获得的国内价格 为 。 因
27、此国内价格低于国外价格： 这会方便我们使用 参考国内价格，但是读者必须保持清醒的头脑就是价格高于或低于世界价格取决于国家的比较优势。 3.1 严格的政策 固定的排放程度。贸易自由化对环境的影响取决于环境政策。我们从 一个简单的分析开始，政府政策是持有固定的生产排放强度。这个内容是有启发的，因为它简化了分析，排除了技术的影响，可能在很多国家是接近最真实的相似政策（至少在短期内）因为污染条例的规定倾向于目标强度的排放，而不是总的排放量。并且，这种条例包括了无污染的特殊条例规定。 首先，思考一个国家进口了肮脏物品 ，国内价格最初高于世界价格，以及随着贸易摩擦的下降，国内相对价格 也下降。随着经济的增
28、长，我们可以将贸易自由化的影响分解成规模效应，结构效应和技术效应。具体见图 ，生产边界（对于给定的排放强度）图中所示为图的上半部 分，污染的测量以 分界在底部的下一半。 生产商的价格为 在 A 点，贸易自由化减少了国内 生产厂 商的价格 X 到 点 ，产量从 A 点 转 移到 C 点，污染 从 Z0 下 降到 了 Z2。 如果我们测量产量的规模，国际市场世界价格为 p，然后假设沿着 AB 虚线向下移动（斜率为 p）保持规模经济不变。 这个污染程度的变化 我们 可以分解成结构效应（ A 到 B），它降低了污染 使它 从 Z0 到 Z1，规模效应（ B 到 C） ，它使污染程度从 Z1 上升到了
29、Z2。如上所述， 技术效应在这个例子中没有影响假设 。 规模效应是积极的，会增加污染。贸易增加 了 生产效率（以世界价格为准），这将导致更多 的 产出，因此导致更多的污染。结构效应的影响 是否定的，因为保护主义已被从污染商品中删除，诱导生产商转移到清洁商品。 在我们简单模型中，其中 只有一种商品的污染 ，结构效应总是支配着规模效应， 因为贸易自由化明确影响着污染产品的输出。如果经济在清洁商品中具有比较优势，在这个例子中，贸易对环境的影响是有利的。 相反，如果国内出 口 X，那么贸易自由化将增长 。生产者沿着生产边界转向肮脏物品。这既增加了生产的规模也使产品的构成转向了污染商品， 规模效应和结构效应相辅相成，并引起污染的增加。 总之，在固定排放强度中，结构效应在确定贸易自由化影响中是至关重要的，此外，结构效应的最终决定是根据国家的比较优势，如果一个国家在干净的行业拥有优势，那么清洁产业随着贸易扩大；相反，如果它在污染行业拥有优势，那么肮脏的产业就随着贸易扩大。 固定的排放污染许可证。现假设政府使用销售排放许可证制度来限制污染，而且它不会因为贸易制度的改变调整许可证的供应。以前，我们知道将许可证和税收制度等价是作为执行的第一个最好的方法。但是如果我们始终用固定不变的政策面对经济的冲击 ，这就会打破这种平衡。
