The Kyoto Protocol is an international agreement linked to the United Nations Framework Convention on Climate Change (UNFCCC). It supplements and strengthens the UNFCCC through setting binding targets for industrialized countries and the European Union (EU) for reducing greenhouse gas (GHG) emissions.

The Protocol was adopted at the third session of the Conference of Parties (COP) to the UNFCCC in 1997 in Kyoto, Japan. It took effect in February 2005.

The major distinction between the Protocol and the UNFCCC is that the Convention encourages developed nations to control GHG emissions, while the Protocol, a binding document, commits developed countries to do so.

Currently, there are 192 parties, or 191 countries and one regional organization to the Protocol.

Under the Protocol, developed countries would reduce their collective greenhouse emissions by 5.2 percent from 1990 levels during the first commitment period (2008-2012), primarily through meeting their national targets.

National targets range from 8 percent reduction for the EU to 7 percent for the United States, and 6 percent for Japan and Canada.

The emission cut targets of the developed countries during the second commitment period (2012-2020) are being negotiated.

The Kyoto Protocol is a long-standing agreement, and its first commitment period, instead of the Protocol itself, will expire in 2012.

In recent years, some developed countries have expressed dissatisfaction with the principle of "common but differentiated responsibilities" set up in the UNFCCC, demanding that the developing countries should also commit themselves to the binding targets on emission cuts.

Besides national measures, the Kyoto Protocol also offers countries three market-based mechanisms to meet their targets for emission reduction - emission trading, clean development and joint implementation.

The Kyoto Protocol lists six gases as direct greenhouse gases - carbon dioxide, methane, nitrous oxide, sulphur hexafluoride, hydrofluorocarbons and perfluorocarbons. It also lists some indirect greenhouse gases, such as sulphur dioxide.

To discuss future commitments for industrialized countries under the Kyoto Protocol, the COP serving as the Meeting of the Parties to the Kyoto Protocol established a working group in December 2005 called the Ad Hoc Working Group on Further Commitments for Annex 1 Parties under the Kyoto Protocol (AWG-KP).