"The first treaty to address climate change, the United Nations Framework Convention on Climate Change (UNFCCC), was completed and opened for signature in 1992. This treaty includes commitments to establish national action plans for voluntary measures that could reduce greenhouse gas emissions to 1990 levels in order to begin mitigating possible global warming. The United States was one of the first nations to sign and ratify this treaty, and it entered into force in 1994. Each of the industrialized nations listed in Annex B of the Kyoto Protocol has a specified emissions target. Overall, the collective commitments are to reduce the Parties' emissions by at least 5% below their 1990 levels, averaged over the 'commitment period' 2008 to 2012. On a 'parallel track' of activities, the United States took an initiative in 2005, the Asia-Pacific Partnership for Clean Development and Climate, together with China, India, Japan, Australia, and South Korea, which is a voluntary effort (though without specific targets) to reduce the greenhouse gas intensity of their economies through technology cooperation. As of December 2006, the UNFCCC Secretariat reported that 168 nations and the European Union have ratified or accepted the Kyoto Protocol. Annual meetings of the parties continue, and attention during the negotiations has turned in large part to 'next steps' following the end of the commitment period in 2012, as well as a review of the effectiveness of the Protocol. Major challenges remain to find agreement on the nature of commitments, if any, that would prove acceptable to all major players: current parties, developing countries that are major emitters, and the United States."
CRS Report for Congress, RL33826