The United Nations Framework Convention on Climate Change (UNFCCC) established an international environmental treaty to combat "dangerous human interference with the climate system", in part by stabilizing greenhouse gas concentrations in the atmosphere. It was signed by 154 states at the United Nations Conference on Environment and Development (UNCED), informally known as the Earth Summit, held in Rio de Janeiro from 3 to 14 June 1992. Its original secretariat was in Geneva but relocated to Bonn in 1996. It entered into force on 21 March 1994.

The treaty called for ongoing scientific research and regular meetings, negotiations, and future policy agreements designed to allow ecosystems to adapt naturally to climate change, to ensure that food production is not threatened and to enable economic development to proceed in a sustainable manner.

The Kyoto Protocol, which was signed in 1997 and ran from 2005 to 2020, was the first implementation of measures under the UNFCCC. The Kyoto Protocol was superseded by the Paris Agreement, which entered into force in 2016. By 2022, the UNFCCC had 198 parties. Its supreme decision-making body, the Conference of the Parties (COP), meets annually to assess progress in dealing with climate change. Because key signatory states are not adhering to their individual commitments, the UNFCCC has been criticized as being unsuccessful in reducing the emission of carbon dioxide since its adoption.

The treaty established different responsibilities for three categories of signatory states. These categories are developed countries, developed countries with special financial responsibilities, and developing countries. The developed countries, also called Annex 1 countries, originally consisted of 38 states, 13 of which were Eastern European states in transition to democracy and market economies, and the European Union. All belong to the Organisation for Economic Co-operation and Development (OECD).

Annex 1 countries are called upon to adopt national policies and take corresponding measures on the mitigation of climate change by limiting their anthropogenic emissions of greenhouse gases as well as to report on steps adopted with the aim of returning individually or jointly to their 1990 emissions levels. The developed countries with special financial responsibilities are also called Annex II countries. They include all of the Annex I countries with the exception of those in transition to democracy and market economies. Annex II countries are called upon to provide new and additional financial resources to meet the costs incurred by developing countries in complying with their obligation to produce national inventories of their emissions by sources and their removals by sinks for all greenhouse gases not controlled by the Montreal Protocol. The developing countries are then required to submit their inventories to the UNFCCC Secretariat.