In May 1992, the UNFCCC was opened for signature at the Earth Summit in Rio de Janeiro. It entered into force on March the 21st, 1994 with 166 signatories. The aim of the UNFCCC is to stabilize concentrations of greenhouse gases in the atmosphere at safe levels.
Under the terms of the UNFCCC, Annex 1 countries, which essentially comprise developed countries and economies in transition, agreed to reduce their emissions of six greenhouse gases to a safe level that would prevent interference with the climate system.
In order to do so, it was agreed that Annex 1 countries would work to adopt national plans with the aim of reducing greenhouse gas emission levels back to 1990 levels by the year 2000. Negotiations concerning how this obligation would be implemented continued at subsequent conferences of the parties ("COPs").
At COP 3, held in Kyoto, Japan in December 1997, the parties to the UNFCCC signed the Kyoto Protocol, under which the parties agree to improve upon the emission reduction targets set out in the UNFCCC. The parties to the UNFCCC agreed that countries listed in Annex B to the Kyoto Protocol (essentially the same countries listed in Annex 1 to the UNFCCC) would reduce or limit their greenhouse gas emissions based on their 1990 emission levels by the conclusion of the first compliance period (from 2008 until 2012).
Each Annex B country agreed to accept a specific binding emission reduction target to achieve during this period. Those countries not listed in Annex B also agreed to the emission limitation and reduction at the Kyoto Protocol, but, under the principle of "common but differentiated responsibilities", did not undertake binding obligations to achieve set emission reduction targets.
To assist the Annex 1 countries to achieve their emission reduction targets, the Kyoto Protocol incorporated three mechanisms:
Decisions on several issues, most notably the Kyoto mechanisms, remained outstanding for several years while the parties continued negotiations. The parties finalized the substance of these decisions at COP 7 in Marrakesh in October and November 2001. The agreement reached at Marrakesh (the "Marrakesh Accords") provides a comprehensive agreement on the development and operation of the UNFCCC and Kyoto Protocol