開放經濟體系下的最適貿易及環境政策

本文以寡占市場結構下的國際貿易為背景，討論政府的最適產業、貿易和環境政策。首先，本文以一個標準的Brander and Spencer (1985)三國兩廠商雙占出口貿易模型的設定並考慮環境問題的情況下進行分析。在此設定下的出口補貼，由於污染稅的課徵會使本國廠商在決定最適污染防治量的同時達成出口補貼原來的效果，因此不需採取出口補貼政策，只要採行最適的污染稅－皮古稅即可同時達到移轉外國利潤與矯正污染外部性的目的。其次，本文討論一個兩國兩廠商的雙占進口貿易模型。此時最適的污染稅為皮古稅，最適的產業政策為對本國廠商補貼至市場價格等於邊際社會成本，最適關稅則值得特別注意。在考慮了環境污染的模型設定下，課徵關稅所造成的效果比傳統設定下的關稅多了一個本國廠商增加污染防治的效果：對外國廠商課徵關稅可使本國廠商增加污染防治，使得本國政府無需課徵太高的關稅以達到移轉外國廠商利潤的目的，因此，最適關稅會小於傳統策略性貿易政策文獻中的最適關稅。

關鍵字

污染稅；污染防治；出口補貼；關稅

並列摘要

This paper studies the optimal industrial, trade, and environmental policies for an oligopolistic market structure. First, we extend the three-country, duopolistic, export competition model of Brander and Spencer (1985), incorporating environmental issues. The optimal pollution tax can induce optimal pollution abatement as well as achieve the same effects as the optimal export subsidy. The Pigouvian pollution tax alone can shift rents from the foreign firm and correct externalities caused by pollution. Hence, the Pigouvian pollution tax can fully replace the export subsidy. Second, we consider a two-country, duopolistic, import model. In this case the optimal pollution tax is a Pigouvian tax and the optimal subsidy rate makes the market price equal to the marginal cost. The tariff generates one more effect, pollution abatement, on domestic and foreign firms: Imposition of the tariff on the foreign firm makes the domestic firm increase pollution abatement, which in return reduces the optimal tariff rate to shift the foreign firm’s rents. As a result, the optimal tariff rate when pollution exists is strictly less than that in the conventional strategic trade literature without pollution.

並列關鍵字

pollution tax ； pollution abatement ； export subsidy ； tariff

參考文獻

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