排放權交易、跨國聯合減量與減量成本極小化

Emission Trading, Joint Implementation, and Minimum Abatement Cost

本研究係探討排放權交易機制與跨國聯合減量機制對二氧化碳減量成本的影響，因為這兩種機制均是1997 年京都議定書中所建議的二氧化碳減量政策。一些研究文獻已指出排放權交易機制是最具成本有效性的政策；同時，只要投資國的二氧化碳減量成本高於被投資國，透過跨國聯合減量政策的執行，減量成本一定會減少。當然，跨國聯合減量政策的執行，一定會排除被投資國原有的減量措施，而以投資國之先進減量技術取代之。一但執行跨國聯合減量政策，投資國的利得理應高於被投資國損失的機會成本。所以本研究發現在兩國減量技術水準有顯著差異時，若能同時執行排放權交易政策與跨國聯合減量政策，則在達成承諾減量的目標下，兩國二氧化碳減量成本之加總將會達於極小化。

This study tries to find the impacts of emission trading and jointimplementation policies on the total CO2 abatement cost. Both policieswere proposed in 1997 Kyoto Protocol. Some studies concluded that theemission trading was the most cost-effective policy. It is also believedthat the joint implementation can reduce the abatement costs when theinvesting country’s abatement cost is higher than it in the host country.And the joint implementation will strip the opportunity of doing thedomestic abatement action by the host country. Whenever the jointimplementation can be applied, the benefits obtained by the investingcountry must be higher than the lost of opportunity cost in the hostcountry. This study finds that the emission trading and jointimplementation can be applied simultaneously when the abatementtechnology used in each country has significant difference. Meanwhile,the total abatement costs of the whole system, that is the summation ofindividual country’s abatement cost, will be minimal to achieve the CO2abating target.