The 2009 Copenhagen climate summit may in retrospect prove a critical turning point in the evolution of the international climate change effort. For a decade and a half, the principal aim under the U.N. Framework Convention on Climate Change (UNFCCC) had been to establish, and then to extend, a legally-binding regime regulating greenhouse gas (GHG) emissions. Despite late efforts to temper hopes for Copenhagen, the general expectation was that the summit would carry forward this process by producing a legally-binding outcome. The result, instead, was the Copenhagen Accord, a non-binding agreement that captured political consensus on a
number of core issues but in the end was not formally adopted by the official Conference of the Parties (COP). This paper explores the evolution of multilateral regimes and implications for the future of the climate change regime.