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. On 8 On 22 December 2012, following the 2012 United Nations Climate Change Conference, an agreement was reached to extend it until 2020 and set a date of 2015 for the preparation of a follow-up document to be implemented from 2020 (see for more information).  The outcome of the Doha talks received a mixed reception, with small island states being critical of the package as a whole. The second Kyoto commitment period applies to approximately 11% of annual global greenhouse gas emissions. Other outcomes of the conference include a timetable for a global agreement that is expected to be adopted by 2015 and will cover all countries.