As explained in this C2ES edition letter, the participation of the United States in the Paris Agreement can only be decided by the President, without, among other things, seeking the Council and the approval of the Senate, because of the establishment of an existing treaty, the United Nations Convention on Climate Change. If Biden is president, he would have enough authority to join it as an “executive convention.” It was a significant concession to the Obama administration`s belief that a Republican-controlled Senate would not ratify such a climate agreement. The agreement was then conceived as an extension of existing international agreements, which could be approved by executive order. Although only national governments are directly involved in the negotiations, COP 21 has provided many opportunities to showcase the contributions of “non-state actors” to global climate efforts. The strong presentation of commitments made by cities, sub-national governments and businesses at the New York climate summit in September 2014 led to the implementation of the Lima-Paris action agenda at COP 20 and the online portal “Non-State Actor Zone for Climate Action” (NAZCA), which allows non-state actors to register their commitments. Until Paris, the portal listed nearly 11,000 commitments from 2,250 cities, 22,025 companies and hundreds of states/regions, investors and civil society organizations. Unprecedented action and support at all levels of society have been widely recognized as an important factor in the success of Paris. Governments and stakeholders are working to strengthen non-governmental contributions to the UNFCCC. The official objective of the agreement is to prevent the 2C world from becoming warmer than before industrialization.
But its goal is to limit warming to 1.5 degrees Celsius, a best-case scenario that scientists see slipping out of reach. Although this has been going on for a long time, there is still a sense of disappointment for many Americans who believe that climate change is the greatest global challenge and that the United States should oppose it. The level of the NDC set by each country will determine the objectives of that country. However, the “contributions” themselves are not binding under international law because of the lack of specificity, normative nature or language necessary to establish binding standards.  In addition, there will be no mechanism to compel a country to set a target in its NDC on a specified date and not for an application if a defined target is not achieved in an NDC.   There will be only a “Name and Shame” system  or as UN Deputy Secretary General for Climate Change, J. Pésztor, CBS News (US), a “Name and Encouragement” plan.  Since the agreement has no consequences if countries do not live up to their commitments, such a consensus is fragile. A cattle of nations withdrawing from the agreement could trigger the withdrawal of other governments and lead to the total collapse of the agreement.  The World Resources Institute also has useful information on when and how countries have joined the Paris Agreement. So did the Center for Climate and Energy Solutions, which was a resource for this burning issue.
National communication reports often cover several hundred pages and cover a country`s actions to reduce greenhouse gas emissions, as well as a description of its weaknesses and effects of climate change.  National communications are established in accordance with guidelines adopted by the UNFCCC Conference of Parties. Contributions (planned) at the national level (NDC), which form the basis of the Paris Agreement, are shorter and less detailed, but also follow a standard structure and are subject to technical review by experts.