Steps for Entry into Force of the Paris Agreement

Paris Agreement

The first step: is for countries to sign the Agreement. Signing signals that country’s support for the Paris Agreement and its intention to align its domestic policies with the Agreement terms and start the process of formally joining the Agreement.

The second step: undertake domestic processes to formally join (or ratify) the Agreement and ‘consent to be bound’ by its terms.

The third step: once a sufficient number of countries (55) covering a certain percentage of emissions (55%) have formally joined the Paris Agreement it will enter into force.


  • On the 22 April 2016, the UN Secretary General will host government representatives having the authority to sign the Paris Agreement including Heads of State, Ministers for Foreign Affairs and climate envoys in New York. Each representative will sign the Agreement reiterating that country’s support for the accord and conveying that country’s commitment to follow through on the domestic ratification processes needed to square the deal with a country’s domestic laws.
  • At the signing ceremony nations have been asked to announce an intended timetable for their country’s ratification process.
  • While in New York, leaders are invited to deposit their instrument of ratification at the same time as signing the Agreement – but this is not a requirement, and will not be possible for those who have not yet finalised domestic ratification processes.
  • By signing the agreement without depositing accompanying instruments of ratification a country is giving political support to the Paris Agreement and, according to the Vienna Convention on the Law of Treaties, has agreed to act in good faith “not to defeat the object and purpose of the treaty.”
  • The window for signing will close on April 21, 2017 (1 year after opening).

Domestic ratification:

  • The Paris Agreement is an international agreement that must be accepted by each country through its own domestic ratification processes. During the ratification process, governments will ensure the compatibility of the Paris Agreement with their own legal and policy context.
  • Once a country explicitly accepts the Agreement by approving it through its appropriate executive and legislative bodies, that country has agreed to be legally bound at the international and national level by the terms of the Agreement once the entire Agreement goes into effect. Once a country has ratified it then becomes a formal Party to the Agreement.
  • Each country’s domestic process for ratifying international agreements is different, and these can vary widely in their degree of complexity and legislative timetable.
  • Some countries will be able to ratify the Paris Agreement swiftly through use of executive powers (e.g. the USA), others can do so through executive power in consultation with the legislature (e.g. Australia), while others will need to pass it through and gain the approval of several legislative committees and then both houses of parliament / congress (e.g. Brazil).
  • Some countries have already been able to ratify: Fiji, Palau and the Marshall Islands are the first three countries to ratify the Paris Agreement.
  • And several more countries, including several major emitters, are understood to be backing expedited ratification – with a view to the Paris Agreement entering into force as early as possible, ideally in 2016.

Entry into force:

  • When an international Agreement ‘enters into force’, it becomes legally-binding on all Parties to that Agreement. Entry into force will give the Paris Agreement the force of international law.
  • The Paris Agreement has a double trigger requirement for entry into force. The Paris Agreement stipulates that it will enter into force thirty days after at least 55 Parties to the UNFCCC, which account for at least 55 percent of total global greenhouse gas emissions, have deposited with the UN their instruments of ratification, acceptance, approval or accession.
  • Crossing the 55% emissions threshold will require a number of big emitters to ratify and several including the United States and China seem poised to do so.
  • Entry into force can happen any time after April 22nd and will rely entirely on how swiftly countries initiate and complete their domestic ratification processes.
  • Following entry into force, countries that have ratified the Agreement cannot withdraw for at least 3 years.


How will the 55 percent of emissions be calculated for the purposes of the entry into force?

According to the Agreement, this requirement for the entry into force is to be calculated on the basis of the most up-to-date amount communicated on or before the date of adoption of this Agreement by the Parties to the Convention (i.e. when the Agreement was signed on Dec. 12, 2015). These amounts have been captured in this table.

What happens if countries don’t sign on 22 April?

Countries have one year to sign the Agreement, following which they may ratify, accept or approve the Agreement. States that have not signed will still have the possibility of joining the Agreement by depositing an instrument of accession with the Secretary General.

What does entry into force mean for countries that have not yet ratified the agreement?

While these countries are not beholden to the requirements of the agreement neither are they protected by its provisions nor are they able to actively participate it is governance. Countries that have not ratified can observe meetings of the governing body of the agreement but they can not vote on how the agreement is implemented. Countries can deposit their articles of accession with the UN and ratify the agreement at anytime either before or after it has entered into force. Parties that ratify before the Agreement’s entry into force can provisionally apply the Agreement and inform the governing body that they have begun implementation. For parties that ratify after the Agreement has entered into force the Agreement will go into effect and become binding on that party 30 days after that party has deposited its instrument of accession with the UN.

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