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. These rules of transparency and accountability are similar to those adopted in other international agreements. While the system does not carry financial penalties, the requirements are aimed at easily tracking the progress of individual nations and promoting a sense of global group pressure, which discourages any hesitation between countries that might consider it. On August 4, 2017, the Trump administration delivered an official notification to the United Nations that the United States . .