INTRODUCTION The Fourth meeting of the Conference of the Parties to the United Nations Framework Convention on Climate Change (COP-4) was held from 2nd to 13th November 1998 in Buenos Aires, Argentina.1 With representatives from about 180 countries, numerous Non-Governmental Organisations and the press, more than 5000 participants struggled and argued about climate change and how the Kyoto follow-up-process should be organised. COP-4 brought no significant progress for the mitigation of climate change. For real breakthroughs to take place to occur, the meeting took place too shortly after COP-3 (Kyoto, December 1997) There was not enough time (and only one meeting of the official Subsidiary Bodies to the Convention in June 1998 in Bonn) to prepare further decisions. Moreover, COP-4 threatened to fail after the opening of the conference by the Secretary of Natural Resources and Sustainable Development of Argentina who was elected President of COP-4. With support of the United States Argentina had launched an initiative to invite non-Annex I Parties to establish voluntary commitments under the United Nations Framework Convention on Climate change (UNFCCC).2 Voluntary commitments by non-Annex I Parties had already been discussed amidst much controversy in Kyoto and afterwards, with most developing countries opposing this idea. After intensive discussions during the opening session of COP-4 Argentina was forced to withdraw this proposal and the conference could take up its work. In Buenos Aires, delegates discussed items on a long agenda including Activities Implemented Jointly (AIJ), ‘Flexible Mechanisms’ and commitments of non-Annex I-Countries. All these items were subject to very controversial arguments between industrialised and developing countries, but within these groups as well heavy debates took place and it was not possible to reach consensus on the different positions. The remaining open questions were summarised in the so-called “Buenos Aires Action Plan” which was adopted by delegates at the end. With this plan the parties demonstrate their will to reach substantial progress on the questions of financial mechanisms, the development and transfer of technologies, the adequacy of commitments, Activities Implemented Jointly under the Pilot Phase and the Mechanisms of the Kyoto Protocol no later than COP-6 at the end of the year 2000.