Task Force on National Greenhouse Gas Inventories

Historical Background

IPCC Expert Meeting on SLCF
WMO, Geneva
28 May 2018
Eduardo Calvo, Co-Chair of IPCC TFIOverview• Introduction• Structure of the IPCC
• TFI & WGI• Expert meeting in 2005
• IPCC Assessment Reports• 6th Assessment Report• Objectives of the Expert Meeting• Substances of interest

Introduction
At its 46th Session in Montreal, on 6-10 September
2017, IPCC adopted Decision IPCC/XLVI-6. Short-lived
Climate Forcers:➢The Intergovernmental Panel on Climate Change
decides, to approve the proposal for an expert meetingon Short-lived Climate Forcers to discuss issues onestimation of emissions and estimations of climateeffects.
➢The meeting, organised jointly by TFI and WGI, will takeplace on 28-31 May 2018 in Geneva, Switzerland.

Structure of
the IPCC(2015 -)

IPCC Plenary

IPCC Secretariat

IPCC Bureau(in Geneva,Switzerland)

IPCC Executive Committee
Working
Group I

Working
Group II

Working
Group IIIThe PhysicalScience Basis

Climate Change
Impacts,
Adaptation andVulnerability

MitigationofClimate Change

TSU

TSU

TSU

TSU

(France)(Germany)(UK)(Japan)Authors, Contributors, Reviewers

Task ForceonNationalGreenhouseGasInventories(TFI)

TFI and WGI➢ Task Force on National Greenhouse Gas Inventories (TFI)• develops and refines an internationally-agreed methodology andsoftware for estimation and reporting of national GHG emissions andremovals; and• encourages its use by countries participating in the IPCC and byParties to the UNFCCC.

➢ Working Group I (WGI)• assesses the physical scientific aspects of the climate system andclimate change.
• The main topics assessed by WGI include: changes in GHGs andaerosols in the atmosphere; observed changes in air, land and ocean
temperatures, rainfall, glaciers and ice sheets, oceans and sea level;climate projections, causes and attribution of climate change; etc.

Background (1): Expert Meeting in 2005
➢ Recognizing the potentially significant influence of aerosols on
climate change as identified in the IPCC Third Assessment Report(TAR) published in 2001, an IPCC Expert Meeting on Emission
Estimation of Aerosols Relevant to Climate Change was held inMay 2005.
➢ The objectives of this meeting were:i.

ii.

to conduct a preliminary assessment of issues related to developing
estimates for anthropogenic emissions of aerosols identified in the TAR
as having an impact on climate change; andto discuss the methodological approaches and related issues for
estimating emissions of aerosols. While the whole range of aerosols
was considered, the primary focus was on carbonaceous aerosols
such as black carbon.

Background (2): Expert Meeting in 2005
➢ The expert meeting in 2005 concluded, among others:• Global inventories of emissions of aerosols relevant to climate change
contained significant sources of uncertainty.
• It was not yet possible to reliably produce internationally comparable
national emission estimates and estimate real differences in emission
characteristics between countries.
• Most current global and regional emission inventories were based on avery limited and non-representative set of emission and speciation
factors and often lack the required differentiation of activity data.
• Work was needed to reduce some of the uncertainties (for which, e.g.,less ambiguous measurement methods would be needed).
• Further similar meetings participated by WGI, TFI and other aerosol
inventory experts should be held.
However, no follow-up expert meeting has been held by the IPCC
so far since 2005.

Background (3): IPCC Assessment Reports➢ Understanding of aerosol radiative forcing advanced throughAR4 (2007) and AR5 (2013).
➢ AR4 concluded that aerosol forcings were better understood than
before due to improved in situ, satellite and ground-based
measurements and more comprehensive modelling while thedominant uncertainty in radiative forcing remained, and thataerosols also influence cloud lifetime and precipitation.
➢ AR5 again concluded that aerosols contributed the largest
uncertainty to the total radiative forcing estimate, and revised theestimated direct aerosol effect at –0.27 [–0.77 to +0.23] W m–2
and the cloud indirect effect at -0.55 [-1.33 to -0.66] W m–2.

Background (4): 6th Assessment Report➢ IPCC has started producing the AR6. WGI Contribution will be
produced for approval/acceptance by the IPCC Plenary in 2021.
➢ WGI Chapter 6: Short-lived climate forcers (approved outline)
Executive Summary• Key emissions: global overview, natural, anthropogenic, historical andscenarios• Observed and reconstructed concentrations and radiative forcing• Direct and indirect-aerosol forcing• Implications for greenhouse gas lifetimes• Implications of different socio-economic and emission pathways, including
urbanisation, for radiative forcing• Connections to air quality and atmospheric composition
Frequently Asked Questions

Objectives of this Expert Meeting➢ To review existing methodological work to estimate emissions ofSLCF with a view to considering suitability for the IPCC todevelop methodological guidance;➢ To consider which species of SLCF should be prioritized in thepossible future work to develop inventory methodology, taking
account of uncertainties in emission estimates and possible
applicable common metrics as well as the extent to which it willcontribute to inform decision making in mitigation policies andmeasures;➢ To consider how the inventory methodology on SLCF wouldrelate to the existing inventory methodology on greenhousegases;

Objectives of this Expert Meeting➢ To identify gaps in scientific understanding on estimates ofSLCF emissions that need to be filled in by scientific researchcommunity;➢ To review existing methodological work to quantify the global
radiative direct and indirect effects of SLCF, with a focus on newdevelopments since the 5th Assessment Report of the IPCC;➢ To identify gaps in scientific understanding on estimates of
direct and indirect climate effects of SLCF on radiative forcing
and climate response, including implications on clouds, thatneed to be filled in by scientific research community.

Substances of Interest➢ It should be noted that inventory methodologies on methane and
HFC are already well covered by the 2006 IPCC Guidelines forNational Greenhouse Gas Inventories produced by TFI as wellas the on-going work by TFI to refine the 2006 IPCC Guidelines.
➢ Therefore, the substances of interest at this meeting are:
• Black Carbon• Organic Carbon• PM2.5• NOx• CO• NMVOC (including BVOC)
• SO2
• NH3

Task Force on National Greenhouse Gas Inventories

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