United Nations Framework Convention on Climate Change

The United Nations Framework Convention on Climate Change (UNFCCC) is the UN process for negotiating an agreement to limit dangerous climate change. It is an international treaty among countries to combat "dangerous human interference with the climate system". The main way to do this is limiting the increase in greenhouse gases in the atmosphere. It was signed in 1992 by 154 states at the United Nations Conference on Environment and Development (UNCED), informally known as the Earth Summit, held in Rio de Janeiro. The treaty entered into force on 21 March 1994. "UNFCCC" is also the name of the Secretariat charged with supporting the operation of the convention, with offices on the UN Campus in Bonn, Germany.

The convention's main objective is explained in Article 2. It is the "stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic [i.e., human-caused] interference with the climate system". The treaty calls for continuing scientific research into the climate. This research supports meetings and negotiations to lead to agreements. The aim is to allow ecosystems to adapt to climate change. At the same time it aims to ensure there are no threats to food production from climate change or measures to address it. And it aims to enable economic development to proceed in a sustainable manner. The UNFCCC's work currently focuses on implementing the Paris Agreement. This agreement entered into force in 2016. It aims to limit the rise in global temperature to well below 2 °C (35.6 °F) above levels before the Industrial Revolution, and even aiming to hold it at 1.5 °C (34.7 °F). The Paris Agreement superseded the UNFCCC's Kyoto Protocol which had been signed in 1997 and ran from 2005 to 2020.

By 2022, the UNFCCC had 198 parties. Its supreme decision-making body, the Conference of the Parties (COP), meets every year. Other meetings at the regional and technical level take place throughout the year. The Paris Agreement mandates a review or "global stocktake" of progress towards meeting its goals every five years. The first of these took place at COP28 in the United Arab Emirates (UAE) in 2023.

The treaty sets out responsibilities for three categories of states. These are developed countries, developed countries with special financial responsibilities, and developing countries. The developed countries are called Annex I countries. At first there were 38 of them. Annex I countries should adopt national policies and take corresponding measures to limit their emissions of greenhouse gases. They should also report on steps for returning individually or jointly to their 1990 greenhouse gas emission levels.

It is problematic that key signatory states are not adhering to their individual commitments. For this reason, the UNFCCC has been criticized as being unsuccessful in reducing greenhouse gas emission since its adoption. Parties to the convention have not agreed on a process allowing for majority voting. All decisions are taken by consensus, giving individual parties or countries a veto. The effectiveness of the Paris Agreement to reach its climate goals is also under debate, especially with regards to its more ambitious goal of keeping the global temperature rise to under 1.5 °C.

The IPCC's First Assessment Report appeared in 1990. The report gave a broad overview of climate change science and the scientific consensus to date. It discussed uncertainties and provided evidence of warming. The authors said they are certain that greenhouse gases are increasing in the atmosphere because of human activity. This is resulting in more warming of the Earth's surface. The report led to the establishment of the United Nations Framework Convention on Climate Change (UNFCCC).

The text of the convention was produced during the meeting of an Intergovernmental Negotiating Committee in New York from 30 April to 9 May 1992. The convention was adopted on 9 May 1992 and opened for signature on 4 June 1992 at the United Nations Conference on Environment and Development (UNCED) in Rio de Janeiro (known by its popular title, the Earth Summit). On 12 June 1992, 154 nations signed the UNFCCC, which upon ratification committed signatories' governments to reduce atmospheric concentrations of greenhouse gases with the goal of "preventing dangerous anthropogenic interference with Earth's climate system". This commitment would require substantial reductions in greenhouse gas emissions (see the later section, "Stabilization of greenhouse gas concentrations"). Parties to the Convention have met annually from 1995 in Conferences of the Parties (COPs) to assess progress in dealing with climate change.

Article 3(1) of the Convention states that Parties should act to protect the climate system on the basis of "common but differentiated responsibilities and respective capabilities", and that developed country Parties should "take the lead" in addressing climate change. Under Article 4, all Parties make general commitments to address climate change through, for example, climate change mitigation and adapting to the eventual impacts of climate change. Article 4(7) states: