探討國際排放權交易之策略性干預政策及其對出口競爭力與社會福利之影響

STRATEGIC REGULATION IN INTERNATIONAL CARBON MARKET: THE IMPLICATIONS ON EXPORT COMPETITIVENESS AND SOCIAL

黃一珍(Yi-Chen Huang)

指導教授 ： 李叢禎

國立臺北大學/社會科學學院/經濟學系/碩士(2009年)

摘要

自1997年京都議定書正式簽訂之後，對附件B國家們而言，國際排放權交易市場便成為其遵循排放減量目標最具彈性的機制之一。過往相關文獻大多立基於完全競爭市場結構及沒有政府干預之假設下，著重於國際排放權交易之成本有效性研究。但是事實上，對個別國家而言，由於政府干預會造成廠商遵循成本的變動，進而影響生產成本、出口水準以及社會福利，是故政府可藉由對排放交易的策略性干預達到提高國家出口競爭力以及社會福利的目的。本文的主要目的係考量國家福利極大化下之國際排放交易最適干預政策。

文中建構完全訊息下兩階段賽局，假設國家在商品出口市場從事Cournot數量競爭，但在國際排放權交易市場則皆為價格接受者，政府對國際排放權交易採取課稅或補貼政策，據以說明國家福利極大化目標下之最適政策設計，並探討相對嚴格的交易管制政策是否符合國家福利極大化目標。

本文結果發現，政府最適干預政策的組成可分解為兩個部份，其一為國際排放權交易市場的直接「價格影響效果」，這個效果是指政府可以藉由對放權交易市場的干預，直接讓均衡的排放價格趨向其想要的方向改變；再者為管制對商品市場的間接效果，也稱為「市場份額影響效果」，此效果意謂著政府將採取一個相對寬鬆的減量政策以提高其廠商在商品出口市場的佔有率，而這樣的效果等同於傳統策略性貿易理論裡所提到的出口補貼政策。結合上述兩項效果可知，政府的最適干預政策與其廠商為國際排放權交易市場之買方或賣方、以及「排放權交易密集度」（emissions-trading intensity）有關，一個排放權的賣方國將會永遠採取相對寬鬆的減量政策，但是一個排放權的買方國卻有可能採取相對嚴格的減量政策，而其前提是此買方國的廠商是所謂的排放權交易密集度高的廠商。因而本文得到與傳統對貿易與環境此議題的研究不同的結論，即當一國政府採取較保護環境的相對嚴格的環境政策時，並不一定會降低此國家在商品市場的出口競爭力。

關鍵字

國際排放權交易 ； 策略性干預政策 ； 出口競爭力 ； 社會福利

並列摘要

After the Kyoto Protocol formally comes into effect, international emissions trading (IET) becomes an important flexible mechanism for the Annex-B countries to comply with the reduction of greenhouse gases. Since then there are more and more works studying IET, and most of them have paid a particular attention to the cost-effectiveness of IET. Under the assumptions of perfect competition and no governments’ intervention, cost-effectiveness will be achieved in an IET market. However, individual countries design their abatement policy from the perspective of self-interest, instead of global-interest. Governments might have incentive to intervene in the IET market. More specifically, the variation of firm’s compliance cost caused by government’s intervention implies that firm’s production level changes at the same time. Therefore, it influences the export level and the social welfare of a country. That is, when there is spillover effect on commodity market of emissions regulation, governments may increase the export competitiveness and the social welfare of their own countries by taking strategic environmental policies. On the other hand, the importance of strategic trade policy is decreasing for the globally free-trade trend. It is reasonable that strategic environmental policy may become another policy instrument for governments to rely on. When it comes to government’s environmental regulation and export competitiveness of a country, there is trade-off relationship according to previous literatures on trade and environment. Emissions control is usually objected for the reason that it may hurt one country’s comparative advantage. However, in our analysis, when we take the spillover effect into account, we would like to find whether or not a strict abatement policy will be adopted by a welfare-maximizing government.

This thesis concentrates on the optimal intervention policies in international carbon market and the implications of intervention on the export competitiveness and the social welfare. Our theoretical model is based on a two-stage game with complete information, in which the countries are assumed to be Cournot competitors in export commodity market and price-takers in the IET market. Central to the analysis is to explore the optimal regulation policy, in terms of taxes or subsidies on permit transaction, in an IET market considering the spillover effect on export commodity market. It is shown that governments’ optimal interventions in the IET market can be decomposed into two parts. The first one is the direct price effect by which governments could induce the equilibrium permit price toward firms’ desired direction. And the tax policy could reach this goal. The second one is the indirect effect on commodity export level, which always leads governments to adopt a laxer abatement policy to expand their firms’ market share. In sum, government’s optimal policy is related to the country’s role in international carbon market and the firm’s emissions-trading intensity. A permit-selling country will always take a lax abatement policy, while a permit-buying country will take a strict abatement policy if and only if its firm is trading-intensive. Thus, we can conclude that stricter domestic abatement policies do not necessarily lead to a negative impact on the export competitiveness in commodity market, which differs from the conclusions of traditional theory about trade and environment.

並列關鍵字

STRATEGIC REGULATION ； INTERNATIONAL CARBON MARKET ； EXPORT COMPETITIVENESS ； SOCIAL WELFARE

參考文獻

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