GENEVA, December 5 – The Intergovernmental Panel on Climate Change (IPCC) opened this week registration for experts to serve as Expert Reviewers on the First-Order Draft (FOD) of the 2027 Methodology Report on Inventories for Short-lived Climate Forcers.
This Methodology Report, produced by the Task Force on National Greenhouse Gas Inventories (TFI), will provide guidance on measuring anthropogenic emissions from key short-lived climate-forcing substances, including nitrogen oxides, carbon monoxide, and others, which significantly contribute to global and regional air quality and climate change.
Following the Second Lead Author Meeting held in Istanbul this October, the authors of this Methodology report have prepared a first draft, which will be open for experts worldwide to review and provide comments as of early January 2026.
The review of the First Order Draft is the first of multiple review stages foreseen for every IPCC report. The review process is critical in preparing IPCC reports. It helps ensure scientific rigour, the widest range of perspectives, and relevance and guidance for those who compile emissions inventories.
Scheduled for release in 2027, the Methodology Report on Inventories for Short-lived Climate Forcers will be the first methodology report published by the IPCC in the seventh assessment cycle.
“We have more than 140 authors from 50 countries volunteering their time and expertise to develop the first draft of this long-awaited methodology report. We are now seeking experts worldwide to review and provide their comments, thus ensuring that this methodology report will reflect the latest scientific knowledge,” said Task Force on National Greenhouse Gas Inventories Co-Chair Takeshi Enoki.
Expert Review is the first opportunity for experts to engage with the draft report. All review comments submitted by experts or governments are addressed by the authors. The comments and the author responses, together with the drafts, are published after the report is finalised.
“Engagement of Expert Reviewers is vital. Their insights will help authors to consider diverse perspectives and methodological approaches,” said Task Force on National Greenhouse Gas Inventories Co-Chair Mazhar Hayat.
An online registration process has been developed and is open for prospective expert reviewers via the IPCC web site. Registration will close on 13 February 2026 midnight (GMT +1).
The First Order Draft of the 2027 Methodology Report on Inventories for Short-lived Climate Forcers will be available for Expert Review from 5 January to 27 February 2026.
For more information about the Expert Review of the 2027 Methodology Report on Inventories for Short-lived Climate Forcers, please TFI Technical Support Unit (TSU) at nggip-tsu@iges.or.jp.
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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. It has 195 member states.
Thousands of people from all over the world contribute to the work of the IPCC. For the assessment reports, scientists and 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, assessing the physical science basis of climate change; Working Group II, assessing impacts, adaptation and vulnerability; and Working Group III, assessing 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 has agreed on the outlines of the three Working Group contributions to the Seventh Assessment Report (AR7).
At the Panel’s most recent 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 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