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FAQs About How the Paris Agreement Enters into Force

The Paris Agreement on climate change was adopted in 2015. Countries are now taking the next steps – signing and joining -- to bring the Paris Agreement into force.

The Paris Agreement Tracker, embedded below, allows users to track which Parties have signed or joined the Paris Agreement so far:

What is the difference between adopting, signing and joining the Paris Agreement? What is the significance of each?

The Paris Agreement – like most other international agreements -- goes through three stages before coming into effect: adoption, signing and joining.

The Paris Agreement was adopted on December 12, 2015 at COP21 in Paris, France by the Conference of the Parties (COP) to the UN Framework Convention on Climate Change (UNFCCC).  According to the Vienna Convention of the Law of Treaties, adoption is the formal act that establishes the form and content of an agreement.  By adopting the Paris Agreement, each of the Parties agreed to the text of the Paris Agreement. This does not mean that Parties to the UNFCCC automatically become Parties to the Paris Agreement.

The next step is for Parties to sign the Paris Agreement. The Paris Agreement will be open for signature at the UN in New York from April 22, 2016 to April 21, 2017.  Signing is important because it indicates a commitment by that country to refrain from acts that would defeat the object and purpose of the Agreement. 

After signing, Parties then formally join the Paris Agreement.  This can be done by depositing one of several types of instruments with the Secretary-General to the UN – instruments of “ratification, acceptance or approval.”  There is no time limit for when countries submit these instruments.  A country might deposit its instrument of ratification, acceptance or approval on the same day it signs, or submit it separately much later.  If a country hasn’t signed in the one year timeframe, it can join the Paris Agreement later by submitting an instrument of “accession.” See below for further information of each of these instruments.

For more information, read our blog post, After COP21: What Needs to Happen for the Paris Agreement to Take Effect?

What steps do countries need to take in order to “join” the Paris Agreement?

A country’s ability to join the agreement is conditional on obtaining the required domestic approval for joining the Agreement. The nature of this domestic approval depends on each individual country’s national constitution and legal framework. For example, in Australia, the only requirement is notification and introduction of the agreement in Parliament, whereas in Mexico, the consent of the Senate is also required.  In the United States, international agreements can be joined in a number of different ways, including through the authority of the President, particularly when an agreement is consistent with existing US law.

In addition to receiving domestic approval to join the Paris Agreement, in some cases countries may also need to enact national legislation to implement the Agreement. Whether a country needs to do this will depend on the nature of its existing legislation and regulatory framework.

When a country fulfills its necessary domestic processes, it can deposit its instrument of “ratification, acceptance or approval” indicating its consent to be bound by the agreement. This is a formal document indicating that it has completed all necessary processes and can now join the Agreement as a Party. 

Can a Party that agreed to adopt the Paris Agreement at COP 21 decide not to join?

Technically, yes.  Adopting the Paris Agreement does not require any individual country to subsequently join it as a Party.  However, in the case of the Paris Agreement, it appears likely that most Parties will join for a few reasons. First, the Paris Agreement was the result of five years of extensive negotiations between all the Parties. The purpose of these negotiations was to develop a text that could be joined and subsequently implemented by all Parties. Second, the Paris Agreement received a significant degree of political support at all levels of government. Over 150 Heads of State attended COP21 (the largest ever to attend a UN event). Third, 189 countries (representing 190 Parties to the UNFCCC) have already submitted national climate plans (known as INDCs) to meet the objectives of the Paris Agreement. Domestic efforts to implement these national climate plans are already underway.

How does the Paris Agreement enter into force?

In accordance with Article 21 of the Paris Agreement, the Agreement enters into force “on the thirtieth day after the date on which at least 55 Parties to the Convention accounting in total for at least an estimated 55 percent of the total global greenhouse gas emissions have deposited their instruments of ratification, acceptance, approval, or accession.”

Why are only Parties to the UNFCCC able to join the Paris Agreement?

The Paris Agreement is considered to be “under” the UNFCCC. The UNFCCC is a framework convention, which is relatively common in international environmental law. Framework conventions set out the broad parameters of a regime, including the objectives, core principles, broad commitments from its parties and a general system of governance, and leave the detailed rules and processes of meeting the objectives to subsequent agreements. This ensures that all Parties to the Paris Agreement are also operating within the parameters set by the UNFCCC.

The Kyoto Protocol, the international agreement that preceded the Paris Agreement, was also “under” the UNFCCC, though its provisions differed considerably from those in the Paris Agreement.

Where do the emissions data come from?

For the purposes of determining entry into force, Article 21 of the Paris Agreement provides that the UNFCCC Secretariat will publish a list of the most up-to-date emissions data communicated by Parties. For many Parties, the percentage of emissions contained in this table does not reflect their current emissions.  This is because developing countries have only recently been required to report their national emissions on a regular basis. This will change under the Paris Agreement, with all countries being required to regularly provide a national inventory report of emissions.

The complete table of this emissions data is available here. For more recent emissions date, see WRI’s CAIT Climate Data Explorer.

What is the difference between ratification, acceptance and approval?

According to the Vienna Convention on the Law of Treaties, “ratification” defines the international act whereby a country indicates its consent to be bound to an international agreement. Ratification is evidenced by depositing an instrument of ratification with the depository. This gives Parties the necessary time to seek approval of the agreement domestically and to enact any necessary national legislation to give domestic effect to that agreement.

Instruments of "acceptance" or "approval" of an agreement have the same legal effect as ratification and consequently express the consent of a country to be bound by an agreement. Based on their national Constitutions, some countries accept or approve an agreement rather than ratify.

What is accession?

"Accession" is where a country becomes a party to an international agreement that has already been negotiated and signed by other countries. It has the same legal effect as ratification, acceptance and approval. Accession usually occurs after the agreement has entered into force, but can occur beforehand also depending on the terms of the agreement.

Under the Paris Agreement, any Parties who are unable to sign during the one-year signing period from April  22 2016 to April 21 2017 will be able to join by depositing an instrument of accession. For example, this is how the State of Palestine joined the UNFCCC on December 18 this year. For a complete list of Parties and their method of joining, see the UNFCCC’s page, Status of Ratification of the Convention.

How do countries “deposit” an instrument of ratification, acceptance, approval or accession?

Countries “deposit” their instruments with the Secretary General, who has been appointed by the Paris Agreement as the “Depository.”  The instruments themselves are documents signed by the Head of State that declare that the Government has considered the relevant agreement, either ratifies, accepts, approves or accedes to it and undertakes to faithfully perform and carry out its terms.

As the Depository, the Secretary-General is responsible for accepting the instruments and monitoring the number of Parties and their respective emissions for the purposes of determining entry into force.

This information will also be publically available on the UNFCCC website

Why do some countries need to obtain domestic approval to join the Paris Agreement?

A number of different processes exist for countries to obtain domestic approval to join the Agreement. 

National law, most commonly a national constitution, governs who has what authority and the procedure that must be followed.

The authority to approve joining an international agreement may rest with:

  • Executive only;
  • Executive only, but administrative procedures such as legislative notification are also required;
  • A majority of one house of the legislature;

A super-majority in one body or majority in two separate legislative bodies;

For many countries, authority to enter into international agreements is split between the executive (Head of State, Cabinet or Council) and the legislature (Parliament). For these countries, typically a Head of State is authorized to negotiate and sign an international agreement, but must seek the approval of the national legislature (or Parliament) before formally joining the agreement.

Some countries apply different approval processes depending on the nature of the international agreement. For instance, agreements with major political importance for the country (e.g. peace treaties) can require legislature approval but other agreements only executive approval.

These different domestic approval processes don’t always determine the length of time until approval occurs, but can determine the amount of political will and public support needed to ensure that joining can occur quickly.

In addition to individual countries, it is necessary to separately consider how the European Union will join the agreement. The EU will likely have to act jointly with its 28 member states.   In addition to each individual member state completing their domestic approval processes, the Council of Ministers, with the consent of the European Parliament, will also need to adopt a decision to ratify.  This could take a couple of years to ensure the necessary effort sharing agreements are in place between the EU member states. Past practice indicates that the EU and its member states will likely deposit their instruments of ratification at the same time.

Why is the European Union a separate signatory to its 28 member states?

The European Union is a regional economic integration organization for the purposes of the UNFCCC, and subsequently the Paris Agreement. Each of the European Union’s 28 member states is also a Party to the UNFCCC. Accordingly, the European Union must formally join the Paris Agreement in addition to each of its member states. See previous question for how the European Union may join the Agreement.

Although not a requirement – it is very likely that the European Union and its 28 member states will deposit their instruments of ratification, acceptance or approval on the same day or in the days or weeks following the European Union. This was the case for both the UNFCCC and the Kyoto Protocol.

What is the earliest the Paris Agreement could enter into force?

Under Article 21 of the Paris Agreement, entry into force thirty days after the date the double threshold (at least 55 Parties representing at least 55 percent of global emissions) is met.

It is not possible to accurately predict when the Agreement will enter into force, as it depends both on how quickly countries are able to complete their domestic approval processes, as well as political will to do so. If both conditions for entry into force are met by 7 October this year, the Paris Agreement would enter into force on 6 November 2016, meaning that the first session of the Conference of the Parties to the Paris Agreement would take place in conjunction with COP22 in Morocco at the end of this year. This may not occur, however, as many Parties will need time to complete their respective domestic approval processes.

What if a Party doesn’t join the Paris Agreement, can they still participate in the UNFCCC?

Yes. Whether or not a Party also joins the Paris Agreement does not affect its rights and obligations under the UNFCCC. Meetings of the COP to the UNFCCC will still continue every year in conjunction with meetings of the COP to the Paris Agreement.

What if the Paris Agreement enters into force before a Party can join? How will they participate in decision making?

Once the Paris Agreement enters into force, those countries which have deposited their instruments of ratification, acceptance or approval will be considered Parties to the Agreement. Parties to the Agreement will enjoy the rights and privileges under the Agreement and be subject to their obligations under the Agreement. It is only Parties to the Agreement that are responsible for governance, oversight, and decision-making.

Once the Agreement enters into force, the first meeting of the Conference of the Parties serving as the meeting of the Parties to the Paris Agreement (referred to as the “CMA”) will occur in conjunction with the next COP under the UNFCCC. If the Paris Agreement enters into force relatively early, this could mean that only a small number (55 and over) of countries are considered Parties at the first session of the CMA.

Countries that have not yet joined the Paris Agreement may participate in sessions of the CMA as observers but will not be able to participate in any final decision-making. This right is reserved for Parties to the Agreement.

However, the practice of the UNFCCC has been one of inclusiveness for observers. Parties to the UNFCCC that had not joined the Kyoto Protocol were still able to participate in discussions throughout negotiations, including making interventions and submitting textual proposals on drafts under consideration. It is likely that a similar process will be followed under the Paris Agreement.

For more details, see the information note from the UNFCCC, Entry into force of the Paris Agreement: legal requirements and implications.

If the Paris Agreement enters into force early, will key decisions have to be made at the first CMA?

In the lead up to COP 21, many observers expected that the Paris Agreement would enter force after 2020, in accordance with the mandate of the ADP. However, Article 21 of the Paris Agreement does not provide a date when the Agreement will enter into force. As a result, entry into force it depends on how quickly countries are able to complete their domestic approval processes. It is likely that the Paris Agreement will enter into force well before 2020.

Many of the provisions of the Paris Agreement continue to reflect the initial expectation that the Agreement will enter into force in 2020 and that the first meeting of the Parties to the Agreement also wouldn’t occur until 2020. If the Agreement enters into force early, many of the tasks required to be adopted by the Parties at the first CMA would not be completed. While the deadlines contained in the COP decisions could be extended by subsequent decisions of the COP (i.e. at COP22), the timelines agreed within the Paris Agreement itself are more difficult to change and revisiting them would run the risk of opening up negotiations on the Agreement text again.

One possible procedural solution would be to suspend, rather than close, the first meeting of the Paris Agreement, so that Parties have the time needed to negotiate the large number of modalities, guidelines and procedures required and ensure compliance with the Paris Agreement. This would also provide an opportunity for all Parties to join the Agreement before final decisions were taken (see previous question for more detail).

Suspending the first meeting would mean that the first meeting could continue for more than one year, or even for several years if needed, until the work is finished in accordance with the timeline already agreed by the Parties at COP21.  There is already precedent for such procedural measures under the UNFCCC. The most noteworthy was COP6, which was suspended in 2000 due to Parties being unable to reach agreement on key issues; in that instance, the November COP at The Hague was suspended and resumed in July 2001, in Bonn, Germany (termed "COP 6 bis").There is also a more recent precedent for this in the ADP, which held only two sessions, each consisting of multiple parts over five years; the second session finally closed at COP21.

For more background, see the information note from the UNFCCC, Entry into force of the Paris Agreement: legal requirements and implications.

What if I have more questions?

Please contact Eliza Northrop, Associate, International Climate Initiative

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