The Kyoto Protocol is a protocol to the United Nations Framework Convention on Climate Change (UNFCCC or FCCC), aimed at fighting global warming. The UNFCCC is an international environmental treaty with the goal of achieving "stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system."[1]
The Protocol was initially adopted on 11 December 1997 in Kyoto, Japan and entered into force on 16 February 2005. As of November 2009, 187 states have signed and ratified the protocol.[2]
Under the Protocol, 37 industrialized countries (called "Annex I countries") commit themselves to a reduction of four greenhouse gases (GHG) (carbon dioxide, methane, nitrous oxide, sulphur hexafluoride) . Annex I countries agreed to reduce their collective greenhouse gas emissions by 5.2% from the 1990 level

The Protocol allows for several "flexible mechanisms", such as emissions trading, the clean development mechanism (CDM)
Each Annex I country is required to submit an annual report of inventories of all anthropogenic greenhouse gas emissions from sources and removals from sinks under UNFCCC and the Kyoto Protocol.

Participation in the Kyoto Protocol, as of June 2009, where green indicates the countries that have signed and ratified the treaty, grey is not yet decided and red is no intention to ratify.
The Protocol defines three "flexibility mechanisms"

The flexibility mechanism means that there are « programs » which allow us to emit green house with limits :
EMISSIONS TRADING is a market used to control pollution. There are limits to pollute for all country and when a country want to produce something but to do this he needs to pollute more than the limit, he is meeting other country for sold his green house

Clean Development Mechanism
The developed country pay for promote projects that reduce émissions in developing country and in exchange they gain some crédits to reach