Climate Change Paris Agreement Opens for Signature

On April 22, 2016, 175 out of 196 Parties to the United Nations Framework Convention on Climate Change signed the new international Paris Agreement to address greenhouse-gas-induced climate change. No international agreement has attracted as many signatures on a single day. In addition, 15 nations—all perceiving themselves as particularly vulnerable to the impacts of climate change—deposited their instruments of ratification as well (Barbados, Belize, Fiji, Grenada, Maldives, Marshall Islands, Mauritius, Nauru, Palau, Palestine, Saint Kitts and Nevis, Saint Lucia, Samoa, Somalia, and Tuvalu). Ten announced intentions to deposit their instruments during 2016: Australia, Argentina, Cameroon, Canada, China, France, Mali, Mexico, Philippines, and the United States. Brazil, the European Union, and the Russian Federation pledged to work through their domestic processes to deposit their instruments as quickly as possible.

Delegations of 195 nations plus the European Union adopted the Paris Agreement on December 12, 2015. The Paris Agreement creates a structure for nations to pledge every five years to abate their greenhouse gas (GHG) emissions, to adapt to climate change, and to cooperate to these ends, including financial and other support. A single framework to promote transparency and track progress of Parties' efforts applies, for the first time, to all Parties—whether rich or poor. The Parties also adopted a Decision to give effect to the Paris Agreement. Both the Decision and the Agreement (hereinafter capitalized) are intended to be legally binding on Parties to the United Nations Framework Convention on Climate Change (UNFCCC) and the new Agreement, respectively, though not all provisions within them are mandatory. Both are subsidiary to the UNFCCC, which the United States ratified with the advice and consent of the Senate (Treaty Document 102-38, October 7, 1992). The UNFCCC entered into force in 1994.

Whether the new Paris Agreement or Decision would require Senate advice and consent depends on the content of the agreements. If either were to contain new legal obligations on the United States, it would favor requiring Senate consent to ratification. However, the United States and other Parties to the UNFCCC accepted many legally binding obligations when they ratified the Convention, including control of greenhouse gas (GHG) emissions, preparation to adapt to climate change, international cooperation and support, and regular reporting of emissions and actions with international review. Some have argued that the Paris Agreement does not require more of the United States than it is already obligated to do under the UNFCCC, while others have argued that it does.

Purpose and Post-2050 Balance of Emissions and Removals

The agreement states that it aims to hold

the increase in the global average temperature to well below 2 °C above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5 °C above pre-industrial levels, recognizing that this would significantly reduce the risks and impacts of climate change.

This purpose is stated as enhancing the implementation of the UNFCCC, including its objective to stabilize GHG concentrations in the atmosphere at a level to avoid dangerous anthropogenic interference in the climate system. In order to achieve this "long-term temperature goal," Parties aim to make their GHG emissions peak as soon as possible and then to reduce them rapidly "so as to achieve a balance between anthropogenic emissions by sources and removals by sinks of greenhouse gases in the second half of this century." In other words, the Agreement envisions achieving net zero anthropogenic emissions. While this is arguably synonymous with the UNFCCC's objective of stabilizing GHG atmospheric concentrations, the Agreement puts a timeframe on the objective for the first time. However, as a collective objective, the Agreement provides no means to hold an individual Party accountable if the objective were not met.

Mitigation and Adaptation

The Agreement and Decision establish a single framework under which all Parties would:

  • communicate every five years and undertake "ambitious" Nationally Determined Contributions (NDCs) to mitigating GHG emissions,
  • participate in a single "transparency framework" that includes communicating their GHG inventories and implementation of their obligations, including financial support provided or received, not less than biennially (with exceptions to a few, least developed states), and
  • be subject to international review of their implementation.

All Parties will eventually be subject to common procedures and guidelines. However, while developed country Parties (not defined) must provide NDCs stated as economy-wide, absolute GHG reduction targets, developing country Parties are exhorted to enhance their NDCs and move toward similar targets over time, in light of their national circumstances. Further, flexibility in the transparency framework is allowed to developing countries, depending on their capacities, regarding the scope, frequency, and detail of their reporting. The administrative Secretariat of the Convention will record the NDCs and other key reports in a public registry.

The Agreement also requires "as appropriate" that Parties prepare and communicate their plans to adapt to climate change. Adaptation communications, too, will be recorded in a public registry.

A committee will, in a facilitative and non-punitive manner, address compliance issues under the Paris Agreement. The Paris Agreement contains provisions for voluntary withdrawal of Parties.

The Agreement permits Parties voluntarily to participate in cooperative approaches (implicitly, emissions markets) that "involve the use of internationally transferred mitigation outcomes."


The Agreement reiterates the obligation in the UNFCCC to provide financial support to developing country Parties to implement their mitigation efforts, calling for it to be continuous and enhanced. It uses exhortatory language to restate the collective pledge in the 2009 Copenhagen Accord, of $100 billion annually by 2020, and calls for a "progression beyond previous efforts." For the first time under the UNFCCC, the Agreement encourages all Parties to provide financial support. In addition, in the Decision, the Parties agreed to set, prior to their 2025 meeting, a new, collective, quantified goal for mobilizing financial resources of not less than $100 billion annually to assist developing country Parties. The Decision strongly urges developed country Parties to scale up their current financial support—in particular to significantly increase their support for adaptation. The Agreement recognizes that "enhanced support" will allow for "higher ambition" in the actions of developing country Parties.

Five-Year Assessments

In 2023 and every five years thereafter, the Parties are to perform a "global stocktake" to review implementation of the Paris Agreement and progress toward the purpose of the Agreement and the long-term net zero anthropogenic emissions goal.