Officially titled the "Kyoto Protocol to the United Nations Framework Convention on Climate Change" and adopted in December 1997 at the third session of the Conference of Parties to the UNFCCC (COP3), the Kyoto Protocol established commitments and mechanisms for the reduction of greenhouse gases by industrialized countries and entered into force on February 16, 2005. A total of 125 countries and regions have ratified the Kyoto Protocol, including the European Union, Japan, and Russia, with the United States as a notable exception. The main points of the Kyoto Protocol are as follows:

• 1. For each industrialized country, the Kyoto Protocol establishes legally binding, numerically defined commitments for the reduction of greenhouse gases.
• 2. To help countries meet their commitments, the Kyoto Protocol establishes the three mechanisms of Emissions Trading, the Clean Development Mechanism, and Joint Implementation. Initiatives to increase carbon absorption are also possible under these mechanisms.
• 3. The Kyoto Protocol establishes no new numerically defined commitments for non-industrialized countries.
• 4. The chart below outlines the numerical commitments.
  

  Gases to be reduced	CO2, methane, nitrous oxide, HFCs, PFCs, SF6
  Base year	1990 (1995 for HFCs, PFCs, SF6)
  Period for attaining reductions	2008-2012
  Reduction commitments	5.2% across industrialized countries (individual commitments per below) −8%　15 members of European Union −7%　US (has not ratified) −6%　Hungary, Poland, Canada, Japan −5%　Croatia ±0%　New Zealand, Russia, Ukraine +1%　Norway +8%　Australia +10%　Iceland

• 5. Repercussions for non-compliance
  ･The country must make up the emissions difference plus an additional 30%.
  ･The country is suspended from participation in emissions trading programs.

Although forests absorb and capture carbon dioxide, they do so under specific conditions. Simply put, the mass of plants is the mass of the carbon dioxide that they have absorbed and captured in their leaves, stems, trunks, and other parts. Forests that have matured,
however, are almost equally divided between dead plants that are rotting and releasing carbon dioxide and growing plants that are absorbing and capturing carbon dioxide. Only forests that are in the process of growing can be net absorbers of carbon dioxide.

The Kyoto Protocol reflects these facts, recognizing "afforestation," planting forests on lands not forested in the past 50 years, and "reforestation," planting forests on lands not forested before 1990. Originally, only by performing either of these two activities could a country earn emissions credits. In light of the fact that forest lost since 1990 counts as an increase in carbon emissions, for countries with a high starting percentage of forest like Japan and Canada, it was difficult to meet their commitments either through afforestation or reforestation efforts. These two counties held that proper management of current forests should earn credit for the carbon dioxide absorbed as a result. The Marrakesh Accords recognized forest management, grazing land management, and cropland management as carbon-reducing activities by which countries could earn emissions credits (Kyoto Protocol, Article 3, Clause 4).

Average yearly CO₂ emissions per individual and trees required to absorb

Source: Forestry Agency website

The Kyoto Protocol includes the following flexible mechanisms for fulfilling emission reductions commitments.

As of 2008, Certified Emission Reductions (CERs) earned under the Clean Development Mechanism (CDM) accounted for 90% of all credits issued. Primary CDMs occur through implementing emission reduction projects, whereas secondary CDMs involve trading or reselling primary CDMs.