1、 外文翻译 原文 Is Free Trade Good for the Environment? Material Source: American Economic Review Author: Brian R. Copeland The debate over the role international trade plays in determining environmental outcomes has at times generated more heat than light. Theoretical work has been successful in identifyi
2、ng a series of hypotheses linking openness to trade and environmental quality, but the empirical verification of these hypotheses has seriously lagged. Foremost among these is the pollution haven hypothesis that suggests relatively low-income developing countries will be made dirtier with trade. Its
3、 natural alternative, the simple factor endowment hypothesis, suggests that dirty capital intensive processes should relocate to the relatively capital abundant developed countries with trade. Empirical work by Grossman and Krueger (1993), Jaffe et al. (1995) and Tobey (1990) cast serious doubt on t
4、he strength of the simple pollution haven hypothesis because they find trade flows are primarily responsive to factor endowment considerations and apparently not responsive to differences in pollution abatement costs. Does this mean that trade has no effect on the environment? This paper sets out a
5、theory of how “openness“ to international goods markets affects pollution levels to assess the environmental consequences of international trade. We develop a theoretical model to divide trades impact on pollution into scale, technique and composition effects and then examine this theory using data
6、on sulfur dioxide concentrations from the Global Environment Monitoring Project. The decomposition of trades effect into scale, technique and composition effects has proven useful in other contexts see Grossman and Krueger (1993), Copeland and Taylor (1994,1995) and here we move one step forward to
7、provide estimates of their magnitude. We find that international trade creates relatively small changes in pollution concentrations when it alters the composition, and hence the pollution intensity, of national output. Combining this result with our estimates of scale and technique effects yields a
8、somewhat surprising conclusion: if trade liberalization raises GDP per person by 1%, then pollution concentrations fall by about 1%. In the case of sulfur dioxide concentrations, free trade is good for the environment. We obtain this conclusion by estimating a very simple model highlighting the inte
9、raction of factor endowment and income differences in determining the pattern of trade. Our approach, while relatively straightforward, is novel in three respects. First, by exploiting the panel structure of our data set, we are able to distinguish empirically between the negative environmental cons
10、equences of scalar increases in economic activity - the scale effect - and the positive environmental consequences of increases in income that call for cleaner production methods - the technique effect. This distinction is important for many reasons. 1 Our estimates indicate that a 1% increase in th
11、e scale of economic activity raises concentrations by approximately .3%, but the accompanying increase in income drives concentrations down by approximately 1.4% via a technique effect. Second, we devise a method for isolating how trade-induced changes in the composition of output affects pollution
12、concentrations. Both the pollution haven hypothesis and the factor endowment hypothesis predict openness to trade will alter the composition of national output in a way that depends on a nations comparative advantage. For example in the pollution haven hypothesis, poor countries get dirtier with tra
13、de while rich countries get cleaner.2 As a result, looking for a consistent relationship between additional pollution and openness to trade (across a panel of both rich and poor countries) is unlikely to be fruitful. Instead we look for trades composition effect after conditioning on country charact
14、eristics. We find that openness per se, measured in a variety of ways, has very little consistent impact on pollution concentrations. Openness conditioned on country characteristics has however a highly significant, but relatively small, impact on pollution concentrations. And lastly, our approach f
15、orces us to distinguish between the pollution consequences of income changes brought about by changes in openness from those created by capital accumulation or technological progress. We find that income gains brought about by further trade or neutral technological progress tend to lower pollution,
16、but income gains brought about by capital accumulation raise pollution. The key difference is that capital accumulation favors the production of pollution intensive goods whereas neutral technological progress and further trade do not. One immediate implication of this finding is that the pollution
17、consequences of economic growth are dependent on the underlying source of growth. Another more speculative implication is that pollution concentrations should at first rise and then fall with increases in income per capita, if capital accumulation becomes a less important source of growth as develop
18、ment proceeds. The theoretical literature on trade and the environment contains many papers where either income differences or policy differences across countries drive pollution intensive industries to the lax regulation or low-income country. For example, Pethig (1976), Siebertet al. (1980), and M
19、cGuire (1982) all present models where the costs of pollution intensive goods are lower in the region with no environmental policy. One criticism of these papers is that while they are successful in predicting trade patterns in a world where policy is fixed and unresponsive, their results may be a h
20、ighly misleading guide to policy in a world where environmental protection responds endogenously to changing conditions. Empirical work by Grossman and Krueger (1993) suggests that it is important to allow policy to change endogenously with income levels and in our earlier work (Copeland and Taylor
21、(1994, 1995) we incorporated the Grossman-Krueger finding to investigate how income-induced differences in pollution policy determine trade patterns. While this earlier work produced several insights, it was limited because it ignored the potential role factor abundance could play in determining tra
22、de patterns. In contrast, the model we develop here allows income differences and factor abundance differences to jointly determine trade patterns. This extension is important, especially in an empirical investigation, because many of the most polluting industries are also highly capital intensive.3
23、 The empirical literature in this area has progressed in three distinct ways. First, there are studies that primarily concern themselves with growth and pollution levels and interpret their results as indicative of the relative strength of scale versus technique effects (for example, Grossman and Kr
24、ueger (1993, 1995), Shafik (1994), Seldon and Song (1994), Gale and Mendez (1996), and Dean (1998). Many of these studies also add a measure of openness as an additional explanatory variable. There is a second group of studies that examines how trade flows may themselves be affected by the level of
25、abatement costs or strictness of pollution regulation in the trading partner countries. This approach was pioneered by Tobey (1990), and then employed in the context of the NAFTA agreement by Grossman and Krueger (1993) and for a large cross section of countries by Antweiler (1996). Finally there ar
26、e those studies that employ the U.S. Toxic Release Inventory to infer how changes in production and trade flows has altered the pollution intensity of production in both developed and developing countries. Work along these lines includes Low and Yeats (1992). Overall the results from these studies a
27、re best described as mixed. Apart from specific case studies, there is very little evidence linking liberalized trade in general with significant changes in the environment. In addition, there is little evidence that differences in abatement costs are a significant determinant of trade flows. There
28、is, however, evidence that increases in income will, after a point, lead to lower concentrations of some pollutants. But the role that trade plays in this process is not entirely clear. Finally, there is some evidence that the composition of exports of some developing countries have become dirtier o
29、ver time but these results follow only from a relatively narrow set of toxic pollutants recorded in the U.S. inventory. Ideally an empirical investigation should be able to distinguish between the negative environmental consequences of scalar increases in economic activity - the scale effect and the
30、 positive environmental consequences of increases in income that call for cleaner production methods - the technique effect. Grossman and Krueger and others interpret their hump-shaped Kuznets curve as reflecting the relative strength of scale versus technique effects, but they do not provide separa
31、te estimates of their magnitude.4 As well, an empirical investigation should be able to identify how trade affects average pollution intensity of national output by altering its composition. Many studies include some measure of openness in their regressions to capture a composition effect, but there
32、 is very little reason to believe that openness per se affects the composition of output in all countries in the same way. Without a measure of the compositional effects of trade, we cannot assess whether trades real income gains come at the cost of a dirtier mix of national production. Finally, man
33、y of the existing studies have a very weak theoretical base and this makes inference difficult. Without a causal mechanism linking trade to consequent changes in the environment it is difficult to isolate the effects of trade on the environment from other factors such as technological changes in aba
34、tement activity, capital accumulation, or other sources of real income change. We would be the first to admit that our simple theoretical model carries a heavy burden in providing us with the structure needed to isolate and identify the implications of international trade. We suggest however that ea
35、rlier empirical investigations failed to find a strong link between environmental outcomes and freer trade precisely because they lacked a strong theoretical underpinning. With a more coherent theoretical framework we are able to look in the “right directions“ for trades effect. The remainder of the
36、 paper is organized as follows. In section 2 we outline our theory and in section 3 we describe our empirical strategy. In section 4 we present our empirical results estimating trades effect on pollution. Section 5 concludes. Appendix A contains summary statistics for data, plus additional notes on
37、data sources and methods. Appendix B contains some additional supporting materials. In Appendix C we report resultsfrom a series of sensitivity tests of our specification. 5. Conclusion This paper sets out a theory of how openness to trading opportunities affects pollution concentrations. We started
38、 with a theoretical specification that gave pride of place to scale, technique and composition effects and then showed how this theoretical decomposition is useful in thinking about the relationship between openness to international markets and the environment. In our empirical section we adopted a
39、specification directly linked to our earlier theory. We then estimated this specification paying special attention to the potentially confounding influences introduced by the panel structure of our data set. Our results consistently indicate that scale, technique and composition effects are not just
40、 theoretical constructs with no empirical counterparts. Rather these theoretical constructs can be identified and their magnitude measured. Moreover, once measured they can play a useful role in determining the likely environmental consequences of technological progress, capital accumulation or incr
41、eased trade. These estimates may also be useful in aggregate CGE modeling of the effects of various free trade agreements and other trade reforms see for example, Ferrantino et al.,1996. Overall the results indicate that increases in a countrys exposure to international markets creates small but mea
42、surable changes in pollution concentrations by altering the pollution intensity of national output. While our estimates indicate that greater trade intensity creates only relatively small changes in pollution via the composition effect, economic theory and numerous empirical studies demonstrate that
43、 trade also raises the value of national output and income. These associated increases in output and incomes will then impact on pollution concentrations via our estimated scale and technique effects. Our estimates of the scale and technique elasticities indicate that if openness to international ma
44、rkets raises both output and income by 1%, pollution concentrations fall by approximately 1%. Putting this calculation together with our earlier evidence on composition effects yields a somewhat surprising conclusion: freer trade is good for the environment. 译文 自由贸易有利于环保吗 ? 资料来源 : 美国经济评论 作者： 布莱恩 科普兰
45、 在关于国际贸易在决定环境产出的角色中的争论已经生成比光更多的热量。 在 定义 一系列的 关于开放对贸易和 环境质量挂钩的假设 的 理论工作是成功的，但 在这些假设的 经验 核查已严重滞后 。 其中最重要的是 污染 天堂 所假说，即表明相对较低收入的发展中国家将 被贸易搞得越来越肮脏 。 它的自然选择，简单的要素禀赋假说 ，随着 贸易发展 建议肮脏资本密集的生产工序迁移到相对应的资本 丰富的国家。 格罗斯曼和克鲁格 （ 1993 年），谢斐等 。 （ 1995 年）和托比（ 1990 年） 的经验主义 严重怀疑简单 污染避难所假说 的力量 ，因为他们发现贸易流动的因素主要是回应 捐赠思考和显然
46、的事实 ，显然不是针对污染减排成本的差异 。 这是否意味着贸易环境的影响并没有 存 在？ 这些论文列举了开放如何对国际商品市场对污染的程度去评价国际贸易的环境结果的理论 。 我们开发 一个理论模型 把贸易在 污染 的 影响 分 到规模 、 技术和 几个方面 ，然后 用来自与 全球环境监测项目 的 浓度二氧化硫 的 数据 来 检查这一理论 。 效果分解贸易进入 规模 、 技术和 结构 的影响已经证明在其他 内容里有用 看到格罗斯曼 和 克鲁格（ 1993），科普兰和泰勒（ 1994,1995） ,在这里，我们 进一步估计他们的 震级 。 我们发现， 当国际贸易 改变了成分， 它 创造相对微小变化
47、 的 污染浓度， 因此这里的 污染强度 就是 国家输出 量 。 结合这结果与我们的规模 效应和 技术效应 的估计 产生一个令人惊讶的结论：如果贸易自由化引起 人均 国内生产总值 上升 1，那么污染浓度下降约 1 。 在硫 二氧化碳浓度 的案例中 ，自由贸易 对于 环境 是好的 。 我们 通过 一个非常简单估计 相互作用的要素禀赋和贸易格局中的收入差距模型 确定 得出 这一结论 。 我 们的方法 ， 相对简单的， 就先小说的三段式 。 首先，通过 利用我们数据集 的 面板结构 ， 我们能够 凭经验 区分 因为 经济活动数量增加带来的 不利的环境后果 规模 效应和增加收入带来的的被叫做清洁生产工具
48、的积极环境后果 技术效应。 这种区分是很重要 有 许多 原因。 我们的估计表明，经济活动规模增加 1的提高 带来 污染 浓度约 0.3 的提升 ，但 收入的 伴随增加 驱动通过技术效应使污染浓度 下降了约 1.4。 第二，我们制定了一个 工具用于隔离 贸易 如何引发在合成物产出的变化来影响 污染浓度组 。 无论是 开放贸易的 污染 天堂 假说 还是 要素禀赋假说预测将改变 国家输出的 构成通过依赖 一个国家的比较 优势。 例如，在 污染 天堂 假说，穷国 变得 肮脏 因为贸易 而富国 变得更为 洁净。 结果， 寻找 额外污染和贸易开放之间的一种一贯的关系 （ 全球 的富国和穷国）是不可能取得成
49、果 的 。 相反， 相反在调节国家特征后我们寻求贸易结构效应。 我们发现，开放本身， 可以用多种方式来测量 ， 对于污染程度 很少有一致的影响 。 国家特征的开放情况然而都有很高的象征性 ， 但相对污染浓度 影响相对较小 。 最后，我们的方法迫使我们要区分 收入变化所带来 的通过资金积累或科技进步的开放性变化引起 的 污染浓度。 我们发现，收入增长所带来的进一步 贸易或中性的技术进步往往 使 污染 降低 ，但 资金积累 带来的收入增长 使 污染 增加 。关键的区别是，资本积累 促进 污染密集型产品而中立 的科技进步 以及进一步的贸易没有。 这个发现的一个最直接含义就 是经济增长的污染后果依赖于源泉的潜在增长。 另一个更投机的含义是， 如果资本积累随着发展收益的变化变成越来越不重要的成长资源， 污染浓度应 随着人均收入先增加后减少。 这个关于贸易与环境里理论文献包含了许多论文，无论国家的收入差异或政策差异驱动的污染集中行业在管理松弛或低收入的国家。 例如， Pethig（ 1976年），西伯特 （ 1980 年），和 McGuire（ 1982） 等人提出污染密集货 物的
