More than 130 countries have confirmed that they will sign the Paris Agreement on that day, the first day that the accord adopted in December in Paris is open for signature, Farhan Haq said at a daily news briefing here.
"This is expected to surpass the previous record of 119 signatures for an opening day signing for an international agreement, set by the Law of the Sea in Montego Bay (in Jamaica) in 1994," he said.
More than 60 heads of state and government will be attending the signing ceremony to be hosted at UN Headquarters in New York by UN Secretary-General Ban Ki-moon, demonstrating the continued high level of engagement by world leaders to accept and implement the Paris Agreement, he said.
"The Signing Ceremony will mark the first step toward ensuring that the Paris Agreement enters into force as early as possible," he said.
"The Agreement will enter into force 30 days after at least 55 countries, accounting 55 percent of global greenhouse gas emissions, deposit their instruments of ratification or acceptance with the secretary-general."
Adopted by the 196 Parties of the United Nations Framework Convention on Climate Change, the Paris Agreement sets a target of holding the global average rise in temperature below 2 degrees Celsius above pre-industrial levels, and preferably below 1.5 degrees.