Implementation of the agreement by all Member States will be evaluated every five years, with the first evaluation in 2023. The result will be used as an input for new national contributions from Member States.  The inventory will not be national contributions/achievements, but a collective analysis of what has been achieved and what remains to be done. 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. The Paris Agreement is the world`s first comprehensive climate agreement.  The Paris Agreement was launched at the signing on April 22, 2016 (Earth Day) at a ceremony in New York.  After the agreement was ratified by several EU member states in October 2016, there were enough countries that had ratified the agreement to produce enough greenhouse gases in the world for the agreement to enter into force.  The agreement came into force on November 4, 2016.
 Once the agreement is signed, all U.S. forces will be withdrawn and all U.S. military operations in the N S. will cease. 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. While the enhanced transparency framework is universal and the global inventory is carried out every five years, the framework must provide “integrated flexibility” to distinguish the capabilities of developed and developing countries. In this context, the Paris Agreement contains provisions to improve the capacity-building framework.
 The agreement recognizes the different circumstances of some countries and notes, in particular, that the technical review of experts for each country takes into account the specific capacity of that country to report.  The agreement also develops a capacity-building initiative for transparency to help developing countries put in place the necessary institutions and procedures to comply with the transparency framework.  At the 2011 UN Climate Change Conference, the Durban Platform (and the ad hoc working group on the Durban Platform for Enhanced Action) were created to negotiate a legal instrument for climate action from 2020.