Technically, yes. The adoption of the Paris Agreement does not require a single country to join it as a contracting party at a later date. However, in the case of the Paris Agreement, it seems likely that most of the contracting parties will join for certain reasons. First, the Paris Agreement was the result of five years of in-depth negotiations between all contracting parties. The aim of these negotiations was to develop a text that could be adopted by all parties and then implemented. Second, the Paris Agreement has received considerable political support at all levels of government. More than 150 heads of state participated in COP21 (the largest ever participated in a UN event). Third, 189 countries (representing 190 parties to the UNFCCC) have already submitted national climate plans (so-called INDC) to achieve the goals of the Paris Agreement. Internal efforts to implement these national climate plans are already underway. The Paris Agreement provides for a number of binding procedural obligations. The parties are committed to preparing, communicating and maintaining successive NDCs; “domestic mitigation measures” to achieve their NDCs; report regularly on their emissions and on progress in implementing their NDCs. The agreement also provides that the successive NDCs of each party “will represent a progression” beyond their previous one and “reflect its highest possible ambitions.” Obtaining their NDC by a party is not a legally binding obligation.
While mitigation and adjustment require more climate funding, adjustment has generally received less support and has mobilized fewer private sector actions.  A 2014 OECD report showed that in 2014, only 16% of the world`s financial resources were devoted to adaptation to climate change.  The Paris Agreement called for a balance between climate finance between adaptation and mitigation, highlighting in particular the need to strengthen support for adaptation from the parties most affected by climate change, including least developed countries and small island developing states. The agreement also reminds the parties of the importance of public subsidies, as adjustment measures receive less public sector investment.  John Kerry, as Secretary of State, announced that the United States would double its grant-based adjustment funding by 2020.  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 in order to assess the 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. As a result, industrialized and developing countries must report every two years on their efforts to combat climate change, and all parties will be subject to technical and peer review.  Countries that have not yet acceded to the Paris Agreement may attend CMA meetings as observers, but cannot participate in final decision-making. This right is reserved for the contracting parties to the agreement.
Once the Paris Agreement enters into force, countries that have tabled their instruments of ratification, acceptance or approval are considered to be contracting parties to the agreement. The parties to the agreement enjoy the rights and privileges of the agreement and are subject to their obligations under the agreement. Only the parties to the agreement are responsible for management, supervision and decision-making. 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 has entered into a