The text of the Protocol to the UNFCCC was adopted at the third session of the Conference of the Parties (COP 3) in Kyoto, Japan, on 11 December 1997; it was open for signature from 16 March 1998 to 15 March 1999 at United Nations Headquarters, New York. By that date the Protocol had received 84 signatures. Those Parties that have not yet signed the Kyoto Protocol may accede to it at any time.

The Protocol is subject to ratification, acceptance, approval or accession by Parties to the Convention. It entered into force on 16 February 2005 - the ninetieth day after at least 55 Parties to the Convention, incorporating Annex I Parties which accounted in total for at least 55 % of the total carbon dioxide emissions for 1990 from that group - deposited their instruments of ratification, acceptance, approval or accession.

The list to the right contains the latest information concerning dates of signature and ratification received from the Secretary-General of the United Nations, as Depositary of the Kyoto Protocol. The dates in the column entitled "ratification" are those of the receipt of the instrument of ratification (R), acceptance (At), approval (Ap) or accession (Ac). (For an explanation of these legal terms, visit the UN's Treaty Reference Guide).