As the United Nations prepares for a special climate event to speed ratification of the Paris Agreement, officials tell Thomson Reuters that they are confident the climate accord will enter into force by the end of the year.

UN officials report that they expect at least 20 countries to formally join the Paris Agreement during the September 21 event in New York, where Secretary-General Ban Ki-moon will invite nations to formally join or bring their commitments to join the agreement before the end of the year.

To enter into force, the agreement requires joining on by at least 55 countries representing at least 55% of the world’s global emissions. The 20 countries expected to join on Wednesday will join the 27 countries, including the U.S. and China, that have already formally joined the agreement.

“When we start to look at the countries that are joining the… agreement and the countries that are going to commit to join before the end of the year, we are absolutely certain that we will have the Paris Agreement on climate change entering into force by the end of 2016,” said David Nabarro, Ban Ki-moon’s special advisor on the 2030 Agenda for Sustainable Development.

World Resources Institute experts confirm that if all the nations that have made pledges to join the agreement in 2016 actually do so, the agreement will meet the thresholds needed to enter into force this year.

Whether this means that the Paris Agreement will enter into force before the next major climate conference in Morocco is still unclear. For this to happen, the agreement would have to meet the 55/55% threshold by October 7, as the agreement enters into force 30 days after meeting these requirements.

The world now looks to the European Union, which has indicated that it may fast-track joining onto the agreement in the next few weeks. To join the agreement, the EU and each of each nations must deposit their ratification documents simultaneously. At this point, only three states — France, Hungary, and Austria — have done so.

Image: Selwin Hart (R), Director of the Secretary-General’s Climate Change Support Team, and David Nabarro, the Secretary-General’s Special Advisor on the 2030 Sustainable Development Agenda, brief journalists on the 21 September high-level event on Entry into Force of the Paris Agreement on Climate Change | Image Credit: UN Photo/Amanda Voisard