The agreement stipulates that it would only enter into force (and therefore fully operational) if 55 countries emitting at least 55% of global greenhouse gas emissions (according to a list established in 2015)  ratify, accept, approve or accede to the agreement.   On April 1, 2016, the United States and China, which together account for nearly 40% of global emissions, made a joint statement confirming that the two countries would sign the Paris climate agreement.   175 parties (174 states and the European Union) signed the agreement on the first day of its entry for signature.   On the same day, more than 20 countries made a declaration of intention to accede as soon as possible in order to accede in 2016. With ratification by the European Union, the agreement obtained enough parts to enter into force on 4 November 2016. Although mitigation and adaptation require increased climate finance, adjustment has generally received less support and mobilized less private sector action.  A 2014 OECD report indicated that in 2014, only 16% of global funds were devoted to climate change adaptation.  The Paris Agreement called for a balance between climate finance between adaptation and mitigation, and in particular highlighted the need to increase support for adaptation to parties most vulnerable to the effects of climate change, including least developed countries and small island developing states. The agreement also reminds the parties of the importance of public subsidies, as adaptation measures receive less investment from the public sector. Trucost, part of S&P Global Market Intelligence, found in 2016 how 2,500 of the world`s largest companies report on their carbon emissions and manage climate risks, which can have a significant impact, that the CO2 reduction targets set by world leaders in 2016 seem quite significant, but actually account for only 16% of the reduction, which is needed to prevent global temperatures from rising to 2 degrees Celsius.
More than 90% of companies in 2018 have active carbon ratio targets, but only 14% have adopted science-based targets. The Paris Agreement is the world`s first comprehensive climate agreement.  On August 4, 2017, the Trump administration officially communicated to the United Nations that the United States intended to withdraw from the Paris Agreement as soon as it had the right to do so.  The withdrawal request could only be filed when the agreement for the United States entered into force on November 4, 2019 for a three-year sentence.   On November 4, 2019, the U.S. government deposited the withdrawal notification with the United Nations Secretary-General, depositary of the agreement, and formally withdrew from the Paris Climate Agreement a year later.  After the November 2020 election, President-elect Joe Biden pledged to reinstate the United States in the Paris Agreement on his first day in office and to renew America`s commitment to mitigate climate change.   When the agreement was reached on the 5th US President Barack Obama said: ”Even if we achieve every goal… .