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.  The negotiators of the agreement stated that the INDCs presented at the time of the Paris conference were insufficient and found that „the estimates of aggregate greenhouse gas emissions in 2025 and 2030 resulting from planned contributions at the national level are not covered by the least costly 2oC scenarios, but lead to a projected level of 55 gigatonnes by 2030.“ and acknowledges that „much greater efforts to reduce emissions will be required to keep the global average temperature rise to less than 2 degrees Celsius, by reducing emissions to 40 gigatonnes or 1.5 degrees Celsius.“  [Clarification needed] The adoption of the Paris Agreement is part of a long-standing effort by the scientific community to combat climate change. It will also enable the contracting parties to gradually strengthen their contributions to the fight against climate change in order to achieve the long-term objectives of the agreement. A study published in 2018 shows a threshold where temperatures could rise to 4 or 5 degrees (ambiguous expression, continuity would be „4-5 degrees Celsius“) compared to pre-industrial levels, compared to pre-industrial levels, thanks to returns of self-amplitude in the climate system, indicating that this threshold is below the 2-degree temperature target agreed in the Paris climate agreement. Study author Katherine Richardson points out: „We find that in its history, the Earth has never had a nearly stable state, warmer than that of pre-industrial, and suggests that there is a significant risk that the system itself, because of all these other processes, will want to continue warming, even if we stop emissions. This means not only reducing emissions, but much more.  Although the United States and Turkey are not parties to the agreement, as they have not indicated their intention to withdraw from the 1992 UNFCCC, they will continue, as a UNFCCC Schedule 1 country, to prepare national communications and an annual inventory of greenhouse gases.  The Foreign Affairs Council adopted conclusions on European climate diplomacy after COP21. The Council highlighted the role of European climate diplomacy in promoting the implementation of the Paris Global Agreement on Climate Change concluded in December 2015.
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.