The United States is a Party to the United Nations Framework Convention on Climate Change (UNFCCC), but not to its subsidiary Kyoto Protocol. Negotiations under way since 2007 have run on two tracks: one under the Kyoto Protocol, to extend commitments of developed parties beyond 2012, and the second track under the UNFCCC, regarding commitments for all Parties. Both tracks convened in Copenhagen, Denmark, in 2009 under a deadline to agree on steps to address climate change beyond 2012. As background for congressional deliberations, this document provides a U.S.-centric chronology of international climate change policy from 1979 to 2010. This chronology identifies selected external events and major multilateral meetings that influence both the current legal and institutional arrangements, and the contentious choices about future international cooperation.