IPCC TFI work on Methodology Report onShort-lived Climate Forcers (SLCFs)
UNFCCC COP28 – Dubai, UAE
9 December 2023 – IPCC Pavilion
Pavel Shermanau – IPCC TFI TSUMandate for Methodology report on SLCFs
IPCC49 (May 2019, Kyoto, Japan) decided that IPCC TFI should develop a new Methodology
Report on SLCFs during AR7 cycle with a preparatory work during AR6 cycle (Decision IPCCXLIX-7).
o Approach
The preparatory work for the Methodology Report (including supporting materials and scoping) iscompleted as soon as possible, starting in the AR6 cycle. Followed by further methodologicaldevelopment in the AR7 cycle

Joint 1st and 2nd IPCC Expert Meeting on SLCFs
o IPCC TFI TSU conducted extensive technical analysis of the main methodological frameworks on
SLCFs source categories and associated emissions:• EMEP/EEA Air Pollutant Emission Inventory Guidebook 2019
• US EPA AP-42: Compilation of Air Pollutant Emissions Factors• UNEP Atmospheric Brown Clouds (ABC) Emission Inventory Manualo This analysis was the basis for discussion at the Joint 1st and 2nd Expert Meeting. It was held inOctober 2021 in online formato Working on the technical documents, this expert meeting successfully achieved its goals:• A complete list of SLCF source categories and associated SLCF species for all sectors –ENERGY, IPPU, AFOLU, WASTE• List of knowledge gaps
o All outcomes (category list, gaps’ list, BOGs’ discussion and conclusions, presentations and tablesfor each sector) are part of the meeting report published at the IPCC TFI website:
https://www.ipcc-nggip.iges.or.jp/public/mtdocs/2110_SLCF.html

Technical analysis performed by IPCC TFI TSU
IPCCcodeACategory

SLCFs

BC

2B Chemical Industry
2B1
Ammonia production

Category List
IPCC
codeANOx, NH3,CO,NMVOC,SOx

Adipic Acid production

NOx, CO,NMVOCYes

EMEP/EEA, UNEP,
US AP-42

Yes

In the 2006 IPCC Guidelines, in the case of ammonia production no distinction is made between fuel and feedstock emissions with all emissions accounted for in
the IPPU Sector.
The method for CO2 and SLCFs is slightly different: input of fuel and its carbon content (IPCC-CO2) by output of ammonia vs. EF of SLCF by output of ammonia(SLCF).

NOx, CO,NMVOCEMEP/EEA – NOx.
UNEP – NOx and NH3
US AP-42 – NOx
EMEP/EEA – NOx, COUNEP and US AP-42 – NOx, CO, NMVOC

Gaps(if any)
HComments
I
D: In the 2006 IPCC Guidelines, in the case of ammonia production nodistinction is made between fuel and feedstock emissions with allemissions accounted for in the IPPU Sector.
The method for CO2 and SLCFs is slightly different: input of fuel and its
carbon content (IPCC-CO2) by output of ammonia vs. EF of SLCF byoutput of ammonia (SLCF).
F: EMEP/EEA – NOx, CO, NH3. NMVOC - Tier2, Tier 2 - technologyspecific
UNEP – NOx, CO, NH3, SOx, NMVOCUS AP-42 – NH3, SO2, CO, NMVOCREAS – NH3
MEP China – NMVOC

2B3

EMEP/EEA – NOx, CO, NH3. NMVOC - Tier2, Tier 2 - technology specific
UNEP – NOx, CO, NH3, SOx, NMVOCUS AP-42 – NH3, SO2, CO, NMVOCREAS – NH3
MEP China – NMVOC

Adipic Acid production

Yes

Yes

I

2B3

EMEP/EEA, UNEP,
US AP-42, REAS,MEP China

EMEP/EEA, UNEP,
US AP-42

CNOx, NH3

Yes, withmodification,
the method isslightly different:
fuel and carbon
content (IPCCCO2) per outputof ammonia vs.
EF of SLCF peroutput ofammonia

Yes

B

Nitric Acid production

F

Globallyapplicable?
GNOx, NH3

Comments

2B2

Available EFs/Parameters

Nitric Acid production

SLCFs

NOx, NH3,
CO, NMVOC,SOx

Alternative
methodology
E

2B2

Category

2B Chemical Industry
2B1
Ammonia production

IPCC
MethodD

F: EMEP/EEA – NOx.
UNEP – NOx and NH3
US AP-42 – NOx
F: EMEP/EEA – NOx, CO
UNEP and US AP-42 – NOx, CO, NMVOC

3rd IPCC Expert Meeting on SLCFs
o The 3rd Expert Meeting further considered issues identified at the Joint 1st and 2nd Meeting anddiscussed cross-cutting issues in relation to the inventory of SLCFs emissions taking into account theassessments in the IPCC WGI and WGIII contributions to AR6
o It was held in April 2022 in online format
o The discussion was focused on three main topics:• Definitions of SLCF species and methods of their identification/quantification• General inventory issues (Data Collection, KCA, UA, Verification, etc.)• Refined Category and Gaps’ listsThe meeting report was published on the IPCC TFI website:
https://www.ipcc-nggip.iges.or.jp/public/mtdocs/2204_SLCF_EM3.html

3rd IPCC Expert Meeting on SLCFs
o The 3rd Expert Meeting concluded, among others:• Most BC/OC emission estimates derive from PM2.5, so PM2.5 information is generally available• The priority for NMVOC reporting is to report the total mass of VOC• Prioritization should be conducted by source category considering all “air pollutant SLCFs” (i.e.
BC, OC, NOX, SO2, NH3, NMVOCs, CO)• It is not recommended to use metrics to compare long-lived GHGs with SLCFs, thus those cannot
be combined in a unique KCA• Given that sources of SLCF emissions are inherently variable and SLCF emissions are impacted
by environmental conditions, consideration of spatial and temporal occurrence of emissions torelate those with climatic factors will be important in developing representative emission factors
and methodologies. So, although SLCF information should be reported at minimum national andon an annual basis, finer regional disaggregation or full spatialization of emissions data along with
their seasonality might therefore be needed to capture SLCF emissions accurately for somesources across all regions of the globe.

Outputs of the Joint 1st & 2nd and 3rd IPCC Expert Meetings on SLCFs
o The following materials were produced:• A complete list of inventory categories with respective SLCF species• Summary tables with relevant information on methods and EFs availability for each category from: EMEP/EEA Air Pollutant Emission Inventory Guidebook 2019
 US EPA AP-42: Compilation of Air Pollutant Emissions Factors
 UNEP Atmospheric Brown Clouds (ABC) Emission Inventory Manual• A list of knowledge gaps
• A list of allocation issues between different sectors• A note on SLCF species definition and relevance• A note on general inventory issues• A consolidated version of Volume 1 of the 2006 IPCC Guidelines and its 2019 Refinement• English Translation of SLCF methodologies used in China

Category List –Example for Energy(excerption)

Note on SLCF species –Example for Black Carbon(excerption)

IPCC TFI Publications on SLCFs (Meeting Reports)

https://www.ipcc-nggip.iges.or.jp/public/mtdocs/1805_Geneva.html
https://www.ipcc-nggip.iges.or.jp/public/mtdocs/2110_SLCF.html
https://www.ipcc-nggip.iges.or.jp/public/mtdocs/2204_SLCF_EM3.html

Scoping meeting
to produce
Table of Contents,Terms of Reference,Workplan

TFB proposes
ToC, ToR, WP
to IPCC61

LAM3(SOD)

IPCC61 approves
the proposal

LAM1 (ZOD)
LAM2 (FOD)

LAM4 (FD)

Production Cycle of Methodology Report

Call for Nominationsof Authors

Selection of Authors.
Preparation for Lead
Author Meeting (LAM1)IPCCXX approves
the report

It takes around3 years(2024-2026)

Scoping processo At IPCC53-bis session (March 2021) the Scoping Meeting was moved from AR6 to AR7 cycleo The nomination letter for the Scoping Meeting was sent by IPCC Secretariat to the IPCC Focal Points
and Observer Organizations on 5 May 2023
o TSU collected nominations received by the end of August 2023
o In November 2023 TFB considered the list of nominated experts and selected participants for theScoping Meting taking into account the expertise, regional and gender balance. The invitation forparticipants was sent out on November 21, 2023.
o The Scoping Meeting will take place on 26-28 February 2024 in Sydney, Australia

Scoping Meeting (expected outcomes)
o The Scoping Meeting shall discuss and decide on the following:• Title and Format of the new Methodology Report on SLCFs• Draft Terms of Reference of the Methodology report• Draft Table of Contents• Draft Workplan• Draft Instructions to Experts and Authorso The outcomes of the Scoping Meeting will be considered by TFB in order to make a proposal to theIPCC Panel (IPCC 61)

Table of Contents –2006 IPCC Guidelines(excerption)

Potential Workplan for the new Methodology Report
DateActionActors

CommentsFebruary 2024

Scoping Meeting

Participants

February 2024

TFB36 Meeting

TFB

Adoption of Outcomes of the Scoping Meeting and Submission to IPCC

March- April 2024

IPCC-61

TFI Co-Chairs

IPCC Plenary approves ToR, ToC, Workplan and Guidance to authors

April 2024

Call for Nomination of Authors and Review Editors

TSU

IPCC invites nominations from governments and international organizations

June 2024

Establishment of the Steering Committee

TFB

June 2024

Selection of Coordinating Lead Authors, LeadAuthors and Review Editors

TFB select members to join TFI Co-Chairs in the Steering Group (to ensure consistency across all
the volumes and continuity with the earlier IPCC inventory reports)

TFB

Selection by TFB considering expertise and geographical and gender balance

Autumn 2024

1st Lead Author Meetings

Authors

LAM1 to develop zero order draft (ZOD)

Spring 2025

2nd Lead Author Meeting

Authors

To develop first order draft (FOD) for review

3rd quarter 2025 (8 weeks)Expert ReviewExperts

8 weeks review by experts

4th quarter 2025

Science Meeting

Authors

A small meeting of CLAs and some LAs to discuss specific issues that require intensive discussion toreinforce the writing process

4th quarter 2025

3rd Lead Author Meeting

Authors

To consider comments and produce second order draft (SOD) for review

1st quarter 2026

Literature cut-off dateAuthors

Only papers published before this date will be considered

1st quarter 2026 (8 weeks)

Government & Expert Review

2nd quarter 2026

4th Lead Author Meeting

Authors

3rd quarter 2026

Government Review

Governments

4th quarter 2026 – 1st quarter 2027

Adoption/acceptance by IPCC

Authors
TFI Co-Chairs

1st quarter 2027

Publication

Governments
Experts

TSUPrepare ToR, ToC, Workplan and Guidance to authors

8 weeks review by governments and experts
To consider comments and produce final draft (FD)Distribute to governments for their consideration prior to approval (at least 4 weeks prior to thePanel)
Final draft submitted to IPCC Panel for adoption/acceptanceElectronic means

Thank you
https://www.ipcc-nggip.iges.or.jp/index.html
https://www.ipcc-nggip.iges.or.jp/meeting/meeting.html