A Kyoto Protocol Amendment Set Targets for 2013 to 2020. It Entered Into Force on 31 December 2020.

by Arjun Mehta · September 2, 2026

Science & Technology Writer, The Globe Ledger

International agreements are usually described by the date they were signed. That date is often the least useful thing about them. A treaty text exists from the moment negotiators approve it, but it binds nobody until enough governments deposit formal instruments with a depositary, and the interval between those two events can be long enough to swallow the entire problem the text was written to address.

The clearest illustration in the climate regime is the Doha Amendment to the Kyoto Protocol. According to the UNFCCC, the amendment was adopted on 8 December 2012 at the eighth session of the Conference of the Parties serving as the meeting of the Parties to the Kyoto Protocol, held in Doha. It established a second commitment period running from 2013 to 2020. The UNFCCC's status page for the amendment records that the text was circulated to all Parties to the Protocol on 21 December 2012.

The amendment entered into force on 31 December 2020. That is the final day of the eight-year period it was written to govern.

What the amendment actually contained

The Doha Amendment was not a minor technical revision. The amendment text sets out that participating Parties would reduce their overall emissions of the covered gases by at least 18 per cent below 1990 levels across the second commitment period. It also added nitrogen trifluoride to Annex A of the Protocol, the list of covered greenhouse gases, applying from the beginning of that second period, and it inserted or modified a series of paragraphs in Article 3 governing how assigned amounts are calculated and carried over.

For comparison, the UNFCCC describes the first commitment period, from 2008 to 2012, as covering 37 industrialised countries and economies in transition plus the European Community, which committed to reduce emissions to an average of five per cent against 1990 levels. The second period raised the headline ambition. It did not, however, carry the same membership: the UNFCCC states plainly that the composition of Parties in the second commitment period differs from the first. In a separate UNFCCC news item on second-period results, the secretariat refers to a group of some 37 countries that took on emission reduction targets under the amendment.

Why it took eight years

The delay follows directly from the Protocol's own drafting. Article 20, paragraph 4 of the Kyoto Protocol provides that an amendment enters into force on the ninetieth day after the depositary receives instruments of acceptance from at least three quarters of the Parties to the Protocol. The UNFCCC counts 192 Parties to the Kyoto Protocol, and its page on the Doha Amendment states that a total of 144 instruments of acceptance, excluding the European Union, were required — three quarters of that membership.

Three quarters is a demanding threshold, and it is calculated against the full membership rather than against the far smaller group of countries that actually took on targets. Most of the 192 Parties had no quantified obligation in the second commitment period at all. They were nonetheless part of the denominator, which meant that ratification by dozens of governments with nothing to reduce was the gating factor for an instrument aimed at roughly three dozen that did.

A UNFCCC news item dated 2 October 2020 reported that the required 144 instruments of acceptance had been received by the treaty depositary in New York, and identified Jamaica and Nigeria as having ratified that day. Ninety days from 2 October falls on 31 December. The arithmetic in Article 20 did the rest.

How many Parties, exactly

The count of acceptances is reported differently by different official sources, and the difference is worth naming rather than smoothing over. The United Nations depositary's status entry for the Doha Amendment, published in the Multilateral Treaties Deposited with the Secretary-General collection, listed 148 acceptances when consulted for this article on 2 September 2026. The UNFCCC's own page on the Doha Amendment also gives 148, expressly stated as of 15 June 2022. The UNFCCC's general Kyoto Protocol page carries a different figure taken at a different moment: 147 Parties as of 28 October 2020, already past the threshold of 144. Both institutions agree on the entry-into-force date. The lesson in the mismatch is the one that applies to every ratification count published anywhere: the number is only meaningful with the date it was taken, and a count quoted without that date is not a fact but a snapshot of unknown vintage.

The contrast the regime learned from

The Paris Agreement, negotiated while the Doha Amendment was still short of its threshold, was built to avoid exactly this outcome. The UNFCCC records that the Paris Agreement was adopted on 12 December 2015 and entered into force on 4 November 2016, a gap of under eleven months. As of 27 January 2026 the UNFCCC counts 194 Parties to it. The difference is structural: Paris is a standalone agreement with its own entry-into-force clause rather than an amendment obliged to clear a supermajority of a pre-existing membership.

What this does and does not mean

It would be wrong to say the second commitment period never operated. Participating Parties reported emissions and accounted for assigned amounts throughout 2013 to 2020, and the UNFCCC's reporting and review machinery for the second period ran during those years. What the eight-year ratification gap meant is narrower and more specific: for almost the entire period, the legal instrument creating the obligations was not yet in force, and the obligations rested on the willingness of the countries concerned to behave as though it were.

That is the durable lesson, and it generalises well beyond climate. When reading any multilateral instrument, the operative questions are which clause governs entry into force, what the denominator for that threshold is, and whether the states whose ratifications are counted are the same states the instrument is meant to bind. In the case of the Doha Amendment, the answer to the last question was no, and the calendar recorded the consequence.