Since November 2020, 194 states and the European Union have signed the agreement. 187 countries and the EU, which account for about 79% of global greenhouse gas emissions, have ratified the agreement or have joined the agreement, including China and India, the countries with the first and third largest CO2 emissions among UNFCCC members.    As of November 2020[update], the United States, Iran and Turkey are the only countries with more than 1% not to be contracting parties. When a country completes its necessary internal procedures, it can file its "ratification, acceptance or approval" in which it gives its consent to obtain the agreement. It is a formal document indicating that it has completed all necessary processes and is now in a position to accede to the agreement as a contracting party. To contribute to the goals of the agreement, countries presented comprehensive national climate change plans (national fixed contributions, NDC). These are not yet sufficient to meet the agreed temperature targets, but the agreement points to the way forward for further measures. The agreement stated that it would only enter into force (and therefore fully effective) if 55 countries that produce at least 55% of global greenhouse gas emissions (according to a list drawn up in 2015)  ratify, accept, approve or adhere to the agreement.   On April 1, 2016, the United States and China, which together account for nearly 40% of global emissions, issued a joint statement confirming that the two countries would sign the Paris climate agreement.  175 contracting parties (174 states and the European Union) signed the agreement on the first day of its signing.   On the same day, more than 20 countries announced plans to join the accession as soon as possible in 2016. The ratification by the European Union has achieved a sufficient number of contracting parties to enter into force on 4 November 2016. The EU and its member states are individually responsible for ratifying the Paris Agreement.
There was a strong preference for the EU and its 28 Member States to simultaneously table their ratification instruments to ensure that neither the EU nor its Member States commit to commitments that belong exclusively to the other and there was concern that there was a disagreement on each Member State`s share of the EU-wide reduction target. just as Britain`s vote to leave the EU could delay the Paris pact.  However, on 4 October 2016, the European Parliament approved the ratification of the Paris Agreement and the EU tabled its ratification instruments on 5 October 2016 with several EU Member States.  For many countries, the power to conclude international agreements is shared between the executive (head of state, cabinet or council) and the legislative branch (parliament). For these countries, a head of state is generally authorized to negotiate and sign an international agreement, but must obtain the approval of the legislative branch (or Parliament) before formally acceding to the agreement. Although the NDC of each contracting party is not legally binding, the contracting parties have a legal obligation to monitor their progress through expert technical reviews to assess performance towards the NDC and to find ways to strengthen ambitions.  Article 13 of the Paris Agreement establishes an "enhanced transparency framework for measures and support" that sets harmonised monitoring, reporting and verification (LVR) requirements.