“ The main advantage of cap and trade is that it facilitates control over the total amount of carbon emissions, ” says Lee. In this respect, it differs from other approaches to reducing greenhouse emissions, such as a carbon tax or mandated efficiency standards, he explains. And ultimately only a global cap can rein in carbon emissions around the world.
依照全球總量管制的原則，富有國家不必完全採「直接」減量，部分比例（10 % 左右，各國規定不同）可以藉購買開發中國家的碳權來「抵消」。