中文摘要
本文描述了一个新事实，并分析其原因与后果：在大多数国家，对污染型产业征收的进口关税及设置的非关税壁垒大幅低于清洁型产业；其中，产业的“污染程度”以其每美元产出的二氧化碳（CO2）排放量来界定。这种贸易政策差异构成了对国际贸易商品中CO2排放的全球性隐性补贴，并加剧了气候变化。这一全球性CO2排放隐性补贴每年总额高达数千亿美元。相对清洁的下游产业受到更高程度的保护，这在很大程度上解释了这一整体格局。下游产业的这种保护模式可由以下理论解释：各产业会游说政府降低其投入品的关税，而最终消费者则组织化程度较低、缺乏有效游说力量。一项量化一般均衡模型表明，如果各国对清洁商品和污染型商品实施相近的贸易政策，全球CO2排放将会减少，而全球实际收入几乎不会发生变化。
Abstract
Abstract This article describes a new fact, then analyzes its causes and consequences: in most countries, import tariffs and nontariff barriers are substantially lower on dirty than on clean industries, where an industry’s “dirtiness” is defined as its carbon dioxide (CO2) emissions per dollar of output. This difference in trade policy creates a global implicit subsidy to CO2 emissions in internationally traded goods and contributes to climate change. This global implicit subsidy to CO2 emissions totals several hundred billion dollars annually. The greater protection of downstream industries, which are relatively clean, substantially accounts for this pattern. The downstream pattern can be explained by theories where industries lobby for low tariffs on their inputs but final consumers are poorly organized. A quantitative general equilibrium model suggests that if countries applied similar trade policies to clean and dirty goods, global CO2 emissions would decrease and global real income would change little.