国际贸易与环境：因果效应、机制及对策研究

What is the impact of trade that may have on the environment? The literature so far, both theoretical and empirical, are generally inconclusive. Firstly, this project creates new instruments such as trade cost based on Baltic Dry Index, exchange rate shock variable, economic growth shock, makes use of the different heating policy across Huai River in China and techniques such as regression discontinuity, nonparametric matching and the identification through heteroskedasticity to estimate the causal effect between international trade and environmental quality and decompose the estimation errors. We use cross country data, Chinese province, city and county level and micro firm level data to quantify the above causal effect. We will use various measures for environment quality and trade openness, the former such as emissions of sulfur dioxide, carbon dioxide, nitrogen oxides (such as nitric oxide and nitrogen dioxide), biochemical oxygen demand (BOD), industrial waste gas, solid waste and waste water intensities, at the same time we also use total suspended particulates (TSPs), particulate matter 2.5, particulate matter 10, air pollution index (API), visibility, fresh water access and the aerosol optical depth (AOD) derived from satellites, etc. as environmental quality indexes, and the latter such as trade GDP ratio, openness extensive margin, intensive margin and tariff reduction, etc. to investigate how international trade affects environment by offering effective and robust evidence empirically. Secondly, we will build theoretical framework and empirical techniques to analyze the mechanisms linking the causal relations. Thirdly, we will do the relevant countermeasures research and raise appropriate policy recommendations based on both the theoretical and empirical analyses.

贸易对环境有怎样的影响呢？理论和实证还没有给出统一的答案。因此，本项目首先将构造波罗的海干货指数、汇率冲击和经济增长冲击等新型工具变量, 利用淮河南北供暖的差别策略和断点回归、非参数匹配、异方差识别等方法来研究贸易对环境的因果影响并进行误差分解。使用跨国和我国省市县、企业等数据对上述因果关系进行定量研究。我们将使用多种环境和贸易开放指标，前者如排放数据二氧化硫(碳)、氮氧化物 、生化需氧量、工业废气(固体废弃物、废水), 大气中悬浮微粒量、PM2.5、PM10、空气污染指数、能见度、清洁水资源和来源于卫星的大气气溶胶光学厚度等指标; 后者如贸易依存度、开放广度(深度)和关税减让等对贸易如何影响环境提供有效和稳健的经验证据; 其次, 我们还将通过建立适当的理论框架和实证策略进行机制上的探索；再次，我们将在理论和实证分析基础上，进行对策研究, 提出合理的政策建议。

贸易对环境和气候有什么样的影响呢？现有的理论和经验还没有给出统一的答案。本项目利用中国宏微观贸易数据和来源于NASA卫星的二氧化硫、氮氧化物和PM2.5等空气污染指标以及国家环保部工业二氧化硫排放和空气质量指数等多种空气污染数据，构建新的贸易开放工具变量和自然实验的背景， 通过二阶段最小二乘、差分回归和断点回归等计量方法识别贸易开放对环境污染的因果影响。我们的研究结果表明贸易的增加特别是污染密集型行业贸易的增加导致了环境污染的增加，可以解释PM2.5增加的60%。研究结论和机制分析对中国来讲意义非常重大,因为环境污染的恶化不利于我们经济的健康发展，需要我们进一步提高开放水平和质量来减小或者消除甚至反转贸易发展对空气污染带来的负面影响。此外，本项目研究过程中还产生了一些新的研究方法、识别技巧和关键数据等，对于我们今后的研究工作起到了重要的方法论作用和数据支撑。