In 2010, Parties agreed on a long-term global goal to reduce GHG emissions so as to hold the increase in global average temperature below 2°C above pre-industrial levels. The COP also decided to periodically review (at least every 7 years) (Decision 1/CP.16, paragraphs 138-140):

1. The adequacy of the long-term global goal in the light of the ultimate objective of the Convention, and
2. Overall progress toward achieving the long-term global goal, including a consideration of the implementation of the commitments under the Convention.

As per its modalities, the COP established a structured expert dialogue (SED) to support the review and to ensure scientific integrity through a focused exchange of views, information and ideas. The final report on the SED is contained in FCCC/SB/2015/INF.1.

The outcome of the 2013-2015 review was a contributing factor to Parties' strengthening of the long-term global goal, i.e. agreeing to pursue efforts to limit the temperature increase to 1.5°C above pre-industrial levels, and in placing it at the heart of the 2015 Paris Agreement (see Article 2.1(a).  Decision 10/CP.21 further decided that Parties should act urgently and ambitiously under the Convention while recognizing the technological, economic and institutional challenges and requested the SBSTA and the SBI to consider the scope of the next periodic review with a view to forwarding a recommendation for consideration by the COP by no later than 2018.

Timeline of the first periodic review

In 2019, at COP 25 in Madrid, Parties agreed to focus the second periodic review on, in accordance with the relevant principles and provisions of the Convention and on the basis of the best available science (Decision 5/CP.25, paragraph 4):

    a) Enhancing Parties’ understanding of:

          i) The long-term global goal and scenarios towards achieving it in the light of the ultimate objective of the Convention;

          ii) Progress made in relation to addressing information and knowledge gaps, including with regard to scenarios to achieve the long-term global goal and the range of associated impacts, since the completion of the 2013–2015 review;

          iii) Challenges and opportunities for achieving the long-term global goal with a view to ensuring the effective implementation of the Convention;

    b) Assessing the overall aggregated effect of the steps taken by Parties in order to achieve the long-term global goal in the light of the ultimate objective of the Convention;

Parties further agreed that the second periodic review will not result in a reinterpretation or redefinition of the long-term global goal.

COP 25 also decided that the second periodic review shall follow its previously agreed modalities, including a structured expert dialogue and that the second periodic review shall start in the second half of 2020 and conclude in 2022.

Summary reports on the first and second meetings of the second periodic review.

Synthesis report by the cofacilitators of the meetings of the second periodic review.

Timeline of the second periodic review

Theme 1 – Enhance Parties’ understanding of: the LTGG and scenarios towards achieving it; progress made in relation to addressing information and knowledge gaps, including scenarios to achieve the LTGG and the range of associated impacts; and challenges and opportunities for achieving the LTGG with a view to ensuring the effective implementation of the Convention

Theme 2 – Assess the overall aggregated effect of the steps taken by Parties in order to achieve the LTGG in the light of the ultimate objective of the Convention

Abbreviations: AR6 – sixth assessment report of IPCC; Inf. Cons – informal consultation; JCG – joint contact group of SABTA and SBI; WG – IPCC Working Group; RT – round table; SED – structured expert dialogue; SRs – Special Reports; SYR – Synthesis Report; 

(Question mark indicates a tentative plan)

The COP will at its twenty-ninth session* (2024), consider the continuation of the periodic review, taking into account experiences from the 2013-2015 periodic review and the second periodic review, as well as from the first global stocktake. The consideration will take into account potential overlaps and synergies between the periodic review, the global stocktake and other relevant processes under the Convention and the Paris Agreement, as well as the availability of new information relevant to the periodic review. 
_{* as per Bureau decision adjusted following the COVID-19 pandemic.}