Countries should also reconsider their commitments by 2020 and present new targets every five years, with the aim of further reducing emissions. They must participate in a «global stocktaking» to measure collective efforts to achieve the long-term goals of the Paris Agreement. In the meantime, developed countries must also estimate the amount of financial assistance they will provide to developing countries to help them reduce their emissions and adapt to the effects of climate change. The 32-page document provides a framework for global climate action, including climate change mitigation and adaptation, support for developing countries, as well as transparent reporting and strengthening of climate goals. The aim is to enable the parties to progressively improve their contributions to the fight against climate change in order to achieve the long-term objectives of the agreement. The agreement states that it would only enter into force (and thus become fully effective) if 55 countries that account for at least 55% of global greenhouse gas emissions (according to a list drawn up in 2015)[65] ratify, accept, approve or accede to the agreement. [66] [67] 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. [68] [69] 175 Contracting Parties (174 States and the European Union) signed the Agreement on the first day of its opening for signature. [59] [70] On the same day, more than 20 countries published a Memorandum of Understanding to which they acceded as soon as possible in order to accede to it in 2016. .