In addition, countries are working to reach "the global peak in greenhouse gas emissions" as soon as possible. The agreement has been described as an incentive and engine for the sale of fossil fuels.   The Paris Agreement provides a sustainable framework that determines global efforts for decades to come. The aim is to increase countries` climate ambitions over time. To achieve this, the agreement provides for two review processes, each in a five-year cycle. 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. Currently, 197 countries – every nation on earth, the last signatory is war-torn Syria – have adopted the Paris Agreement. 179 of them have consolidated their climate proposals with official approval, including, for the time being, the United States.
The only major emitters that have yet to formally accede to the agreement are Russia, Turkey and Iran. It is rare that there is a consensus among almost all nations on a single subject. But with the Paris agreement, world leaders agreed that climate change was driven by human behaviour, that it was a threat to the environment and to humanity as a whole, and that global action was needed to stop it. In addition, a clear framework has been put in place for all countries to make commitments to reduce emissions and strengthen these measures over time. Here are some important reasons why the agreement is so important: the aim of the agreement is to reduce global warming described in Article 2, to "improve the implementation" of the UNFCCC: Although the agreement has been welcomed by many, including French President Francois Hollande and UN Secretary-General Ban Ki-moon, criticism has also emerged.  James Hansen, a former NASA scientist and climate change expert, expressed anger that most of the agreement is made up of "promises" or goals, not firm commitments.  He called the Paris talks a fraud with "nothing, only promises" and believed that only a generalized tax on CO2 emissions, which is not part of the Paris agreement, would force CO2 emissions down fast enough to avoid the worst effects of global warming.  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.  President Obama was able to formally enshrine the United States in the agreement through executive measures because he did not impose new legal obligations on the country.