Tradable emission permits are increasingly regarded as a versatile instrument of environmental policy. The analysis of the benefits and drawbacks associated with the introduction of a trading system presupposes concrete concept definition. However, there is no universally valid concept for permit trading. Although there are basic common features of all concepts, the underlying conditions and consequences differ in every case. This paper discusses EU-wide introduction of emissions trading to reach a reduction in greenhouse gas emissions allowing the commitments under the Kyoto Protocol to be met. After the failure of the Global Climate Summit in The Hague at the end of the year 2000, it is open for the time being whether the Kyoto Protocol has any chance to enter into force in its envisaged form.