GENEVA, Aug 13 – The Intergovernmental Panel on Climate Change (IPCC) has opened registration for experts to serve as Expert Reviewers of the Second-Order Draft (SOD) of the 2027 Methodology Report on Inventories for Short-Lived Climate Forcers (SLCF), which will undergo Government and Expert Review. Scheduled for publication in the second half of 2027, this will be the first methodology report released by the IPCC in the seventh assessment cycle, and it is being prepared by the Task Force on National Greenhouse Gas Inventories (TFI). The Report will provide methodological guidance for estimating and reporting national, annual anthropogenic emissions of Short-lived Climate Forcers. Secondary human-induced substances are outside its scope. ‘Short-lived climate forcers, including nitrogen oxides, carbon monoxide, and others, have significant impacts on global and regional air quality and climate change. Our report will provide clear methodological guidance for inventory compilers on estimating and reporting these emissions,’ said Takeshi Enoki, the Co-Chair of the TFI. Following the Third Lead Author Meeting in April this year in Rome, IPCC authors drafting this Methodology Report have addressed comments from expert reviewers on the First-Order Draft and prepared the Second-Order Draft. The review will open on 31 August for governments and experts worldwide to provide comments and is scheduled to close on 25 October. Experts who registered for the review of the First-Order Draft of the report are automatically registered for this round of review, and further experts may also register at this stage. ‘Our diverse group of authors has addressed more than 6,300 comments on the First-Order Draft. The Second-Order Draft is now ready for the next round of scrutiny, and we invite governments and expert reviewers to engage and provide feedback that will help strengthen the report before it is finalized,’ said Mazhar Hayat, TFI Co-Chair. IPCC reports undergo multiple stages of review, designed to bring in a broad range of expertise, perspectives and geographical representation. For Methodology Reports, this process helps ensure that the guidance is technically robust, transparent, clear and usable by inventory compilers. Once the SOD review closes in October, authors will prepare the Final Draft, reflecting the review comments received. During the final review, governments will submit written comments on the Overview Chapter before the Panel meets in plenary to adopt the Overview Chapter section by section and accept the underlying Methodology Report. Interested experts can register for participation in the review here. The registration of review experts will close on 18 October 2026. For more information IPCC Press Office, Email: [email protected]; Andrej Mahecic, +41 22 730 8516; Werani Zabula, +41 22 730 8120. Notes for editors What is the IPCC? The Intergovernmental Panel on Climate Change (IPCC) is the UN body for assessing the science related to climate change. It was established by the United Nations Environment Programme (UNEP) and the World Meteorological Organization (WMO) in 1988 to provide political leaders with periodic scientific assessments concerning climate change, its implications and risks, as well as to put forward adaptation and mitigation strategies. In the same year, the UN General Assembly endorsed the action by the WMO and UNEP in jointly establishing the IPCC. Participation in the IPCC is open to all member countries of WMO and the United Nations (UN). Thousands of people from all over the world contribute to the work of the IPCC. For the assessment reports, experts volunteer their time as IPCC authors to assess the thousands of scientific papers published each year to provide a comprehensive summary of what is known about the drivers of climate change, its impacts and future risks, and how adaptation and mitigation can reduce those risks. The IPCC has three working groups: Working Group I, dealing with the physical science basis of climate change; Working Group II, dealing with impacts, adaptation and vulnerability; and Working Group III, dealing with the mitigation of climate change. It also has a Task Force on National Greenhouse Gas Inventories that develops methodologies for measuring emissions and removals. IPCC assessments provide governments, at all levels, with scientific information that they can use to develop climate policies. IPCC assessments are a key input into the international negotiations to tackle climate change. IPCC reports are drafted and reviewed in several stages, thus guaranteeing objectivity and transparency. About the Seventh Assessment Cycle Comprehensive scientific assessment reports are published every 5 to 7 years. The IPCC is currently in its seventh assessment cycle, which formally began in July 2023 with the elections of the new IPCC and Task Force Bureaus at the IPCC’s Plenary Session in Nairobi. At its first Plenary Session in the seventh assessment cycle – the 60th Plenary Session in Istanbul, Türkiye, in January 2024 – the Panel agreed to produce in this cycle the three Working Group contributions to the Seventh Assessment Report (AR7), namely the Working Group I report on the Physical Science Basis, the Working Group II report on Impacts, Adaptation and Vulnerability and the Working Group III report on Mitigation of Climate Change. The Synthesis Report of the Seventh Assessment Report will be produced after the completion of the Working Group reports and released by late 2029. During its 62nd Plenary Session held in Hangzhou, China, in February 2025, the Panel agreed on the outlines of the three Working Group contributions to the Seventh Assessment Report (AR7). At the Panel’s Plenary Session in Lima, Peru, in October 2025, member governments agreed on the scientific content of the 2027 Methodology Report on Carbon Dioxide Removal Technologies, Carbon Capture, Utilization and Storage. There, the Panel also agreed on the 2026 workplan for the three Working Group contributions to the Seventh Assessment Report. The Panel decided already during the previous cycle to produce a Special Report on Climate Change and Cities and a Methodology Report on Short-lived Climate Forcers during AR7. At the IPCC’s 61st Plenary Session held in Sofia, Bulgaria, from 27 July to 2 August 2024, the Panel agreed upon the outlines for the Special Report on Climate Change and Cities scheduled for approval and publication in March 2027 and for the 2027 IPCC Methodology Report on Inventories for Short-lived Climate Forcers scheduled for publication in the second half of 2027. In addition, a revision of the 1994 IPCC Technical Guidelines on impacts and adaptation as well as adaptation indicators, metrics and guidelines, will be developed in conjunction with the Working Group II report and published as a separate product. IPCC’s latest report, the Sixth Assessment Report, was completed in March 2023 with the release of its Synthesis Report, which provided direct scientific input to the First Global Stocktake process under the United Nations Framework Convention on Climate Change at COP28 in Dubai. For more information, visit www.ipcc.ch.