IPCC Invites Governments and Experts to Review Second Draft of 2027 SLCF Methodology Report

IPCC Invites Governments and Experts to Review Second Draft of 2027 SLCF Methodology Report

(IN BRIEF) The Intergovernmental Panel on Climate Change (IPCC) has opened registration for experts to review the Second-Order Draft of the 2027 Methodology Report on Inventories for Short-Lived Climate Forcers, which will undergo Government and Expert Review from 31 August to 25 October 2026, with expert registration closing on 18 October 2026. The report, prepared by the IPCC’s Task Force on National Greenhouse Gas Inventories (TFI), is scheduled for publication in the second half of 2027 and will be the first methodology report released during the IPCC’s seventh assessment cycle. It will provide methodological guidance for estimating and reporting national annual anthropogenic emissions of short-lived climate forcers, including nitrogen oxides and carbon monoxide, while excluding secondary human-induced substances. IPCC authors have addressed more than 6,300 comments on the First-Order Draft, and the next review stage will allow governments and experts worldwide to provide further input before the Final Draft is prepared and the Panel later adopts the Overview Chapter and accepts the underlying Methodology Report.

(PRESS RELEASE) GENEVA, 19-Aug-2026 — /EuropaWire/ — The Intergovernmental Panel on Climate Change, known as IPCC, has opened registration for experts to participate as Expert Reviewers of the Second-Order Draft of the 2027 Methodology Report on Inventories for Short-Lived Climate Forcers.

The draft will undergo a combined Government and Expert Review.

The report is scheduled for publication in the second half of 2027 and will be the first methodology report released by the IPCC during its seventh assessment cycle.

It is being prepared by the IPCC’s Task Force on National Greenhouse Gas Inventories, known as TFI.

The report will provide methodological guidance for estimating and reporting national annual anthropogenic emissions of short-lived climate forcers, or SLCFs.

Secondary human-induced substances are outside the scope of the report.

Takeshi Enoki, Co-Chair of the TFI, said short-lived climate forcers, including nitrogen oxides, carbon monoxide and others, have significant effects on global and regional air quality and climate change.

He said the report will provide clear methodological guidance for inventory compilers on how to estimate and report these emissions.

Following the Third Lead Author Meeting, held in Rome in April 2026, IPCC authors have addressed comments from expert reviewers on the First-Order Draft and prepared the Second-Order Draft.

The next review period will open on 31 August 2026, allowing governments and experts worldwide to submit comments.

The review is scheduled to close on 25 October 2026.

Experts who registered for the review of the First-Order Draft are automatically registered for this review round.

Additional experts may also register at this stage.

Mazhar Hayat, Co-Chair of the TFI, said the authors have addressed more than 6,300 comments received on the First-Order Draft.

He said the Second-Order Draft is now ready for further scrutiny and invited governments and expert reviewers to provide feedback that will help strengthen the report before it is finalised.

IPCC reports go through several stages of review to incorporate a broad range of expertise, perspectives and geographical representation.

For Methodology Reports, this review process is intended to ensure that guidance is technically robust, transparent, clear and usable by inventory compilers.

After the Second-Order Draft review closes in October, authors will prepare the Final Draft, taking into account the 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.

Registration for review experts will close on 18 October 2026.

About the IPCC

The Intergovernmental Panel on Climate Change is the United Nations body responsible for assessing the science related to climate change.

It was established in 1988 by the United Nations Environment Programme and the World Meteorological Organization to provide political leaders with periodic scientific assessments on climate change, its implications and risks, and options for adaptation and mitigation.

In the same year, the United Nations General Assembly endorsed the action by WMO and UNEP to establish the IPCC.

Participation in the IPCC is open to all member countries of WMO and the United Nations.

Thousands of experts from around the world contribute to the work of the IPCC.

For assessment reports, scientists volunteer their time as IPCC authors to assess thousands of scientific papers each year and provide a comprehensive summary of knowledge on 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 addresses the physical science basis of climate change.

Working Group II focuses on impacts, adaptation and vulnerability.

Working Group III covers the mitigation of climate change.

The IPCC also has the Task Force on National Greenhouse Gas Inventories, which develops methodologies for measuring emissions and removals.

IPCC assessments provide governments at all levels with scientific information that can support climate policy development.

They are also a key input into international climate negotiations.

IPCC reports are drafted and reviewed in several stages to support objectivity and transparency.

About the Seventh Assessment Cycle

The IPCC publishes comprehensive scientific assessment reports every five to seven years.

The organisation is currently in its seventh assessment cycle, which formally began in July 2023 with the election of the new IPCC and Task Force Bureaus at the IPCC Plenary Session in Nairobi.

At the 60th Plenary Session in Istanbul, Türkiye, in January 2024, the Panel agreed to produce the three Working Group contributions to the Seventh Assessment Report, or AR7.

These will include 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 AR7 will be produced after the completion of the Working Group reports and is expected to be released by late 2029.

At the 62nd Plenary Session in Hangzhou, China, in February 2025, the Panel agreed on the outlines of the three Working Group contributions to 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.

At the same session, the Panel also agreed on the 2026 workplan for the three Working Group contributions to AR7.

The Panel had already decided during the previous assessment 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 on 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, the IPCC will develop a revision of the 1994 IPCC Technical Guidelines on impacts and adaptation, as well as adaptation indicators, metrics and guidelines.

This work will be developed in conjunction with the Working Group II report and published as a separate product.

The IPCC’s latest report, the Sixth Assessment Report, was completed in March 2023 with the release of its Synthesis Report.

That report provided scientific input to the First Global Stocktake process under the United Nations Framework Convention on Climate Change at COP28 in Dubai.

Media Contacts:

IPCC Press Office
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Andrej Mahecic
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Werani Zabula
+41 22 730 8120

SOURCE: IPCC