UNFCCC

The United Nations Framework Convention on Climate Change (UNFCCC) was opened for signature at the Rio Earth Summit in June 1992 and entered into force on 21 March 1994. It is one of three "Rio Conventions," alongside the Convention on Biological Diversity and the UN Convention to Combat Desertification. The treaty has achieved near-universal participation, with close to 200 parties.

Its stated objective, set out in Article 2, is to achieve "stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system." The Convention itself does not set binding emissions limits on individual countries; instead, it provides a framework for negotiating subsequent protocols and agreements.

Key structural features include:

• Common but differentiated responsibilities (CBDR), articulated in Article 3, recognizing that developed countries bear greater historical responsibility for emissions.
• Annex I parties (industrialized economies, including economies in transition) and Annex II parties (a subset expected to provide financial support), with non-Annex I parties comprising developing countries.
• The Conference of the Parties (COP), the supreme decision-making body, which has met annually since COP1 in Berlin in 1995.
• A permanent Secretariat based in Bonn, Germany.

Two major instruments have been adopted under the UNFCCC. The Kyoto Protocol, adopted in 1997 and entering into force in 2005, set binding emission-reduction targets for Annex I parties for the period 2008–2012, later extended by the Doha Amendment. The Paris Agreement, adopted at COP21 in December 2015 and entering into force on 4 November 2016, replaced the Kyoto top-down model with nationally determined contributions (NDCs) and a long-term temperature goal of holding warming "well below 2°C" and pursuing efforts toward 1.5°C.

Subsidiary bodies include the SBSTA (scientific and technological advice) and SBI (implementation), which meet between COPs to advance the negotiating agenda.