IPCC Good Practice Guidance and Uncertainty Management in National Greenhouse Gas Inventories IPCC Good Practice Guidance and Uncertainty Management in National Greenhouse Gas Inventories UNFCCC Workshop on the Preparation of National Communications from non-Annex I Parties April 26-30, 2004, Manila Leandro Buendia Programme Officer, IPCC-NGGIP-TSU

Decision 17/CP.8, Annex (Guidelines for the Preparation of NC from non-Annex 1 Parties) Objectives Para 1b. To encourage the presentation of information in a consistent, transparent and comparable, as well as flexible, manner, taking into account specific national circumstances.

Decision 17/CP.8 Methodologies Para 11. Non-Annex 1 Parties are encouraged to apply the IPCC Good Practice Guidance and Uncertainty Management in National Greenhouse Gas Inventories, taking into account the need to improve transparency, consistency, comparability, completeness and accuracy in inventories. Para 12. Non-Annex I Parties are also encouraged, to the extent possible, to undertake any key source analysis as indicated in the IPCC good practice guidance to assist in developing inventories that better reflect their national circumstances.

Decision 17/CP.8 Reporting Para 24. Non-Annex I Parties are encouraged to provide information on the level of uncertainty associated with inventory data and their underlying assumptions, and to describe the methodologies used, if any, for estimating these uncertainties.

Contents Background Information What is good practice guidance Contents of the Report Key Source Category Policy Relevance Conclusion

Background Information June 1998: SBSTA 8 encouraged IPCC to give high priority to completing its work on uncertainty, as well as to prepare a report on good practices in inventory management and to submit a report on these issues for consideration by SBSTA, if possible by COP5 October 1998: IPCC held a Planning Meeting in Paris to plan for the work January 1999 – October 1999: Sectoral and Cross-sectoral Expert Meetings December February 2000: First draft was reviewed by governments and experts May 2000: IPCC XVI accepted the GPG2000 Report June 2000: SBSTA 12 endorsed the GPG2000

Background Information IPCC Good Practice Guidance and Uncertainty Management in National Greenhouse Gas Inventories (GPG2000) Published in 2000

What is good practice guidance? Good Practice Guidance (GPG) aims to assist countries in producing inventories: in which uncertainties are reduced as far as is practicable that are neither over- nor underestimates so far as can be judged

transparent documented consistent over time complete comparable assessed for uncertainties subject to quality control and assurance efficient in the use of resources Further aims, to produce inventories which are:

Structure of the GPG2000 Preface Chapter 1Introduction Chapter 2Energy Chapter 3Industrial Processes Chapter 4Agriculture Chapter 5Waste Chapter 6Quantifying Uncertainties in Practice Chapter 7Methodological Choice and Recalculation Chapter 8Quality Assurance and Quality Control Annex 1Conceptual Basis for Uncertainty Analysis Annex 2Verification Annex 3Glossary Annex 4List of Participants Source category good practice guidance

Source category specific good practice guidance (Chapters 2 to 5) 1.Methodological Issues Choice of method Choice of emission factors Choice of activity 2.Completeness 3.Developing a Consistent Time series 4.Uncertainty Assessment 5.Reporting and Documentation 6.Inventory Quality Assurance/Quality Control

1. Methodological Issues  Choice of Method estimation methods suited to national circumstances decision trees (which tier?)  Choice of Emission Factors most suitable emission factors for inventory calculation (default values)  Choice of Activity Data most suitable activity data for inventory calculation

Does the country manage cattle, buffalo, sheep, goats, camels, mules/asses, swine, or other livestock? Report ‘Not Occurring’ No Is enteric fermentation a key source category? (Note 1) Ask for each species: Is this sub-source category significant? (Note 2) Yes Estimate emissions for the species using Tier 2 Ask for each species: Are data available with which to perform a Tier 2 estimate? Estimate emissions for the species using Tier 1 Figure 4.2 Decision Tree for CH 4 Emissions from Enteric Fermentation No Yes

2.Completeness  advice to ensure complete estimates 3.Developing a Consistent Time series  advice to ensure consistency throughout the time series 4.Uncertainty Assessment  provide default values for uncertainty ranges

5.Reporting and Documentation  provide what information is necessary for the specific source category 6.Inventory Quality Assurance/Quality Control  guidance and procedures to enable cross-checks during inventory compilations

Chapter 6: Quantifying Uncertainties in Practice  describes GPG in estimating and reporting uncertainties associated with both annual estimates emissions  identifies types of uncertainty from the viewpoint of the inventory practitioner and shows how to obtain expert judgment in a consistent manner  provides two tiers for combining source category uncertainties into an uncertainty estimate for total national emissions

Chapter 7: Methodological Choice and Recalculation  how to identify key source categories in the national inventory  how to systematically manage methodological change overtime and ensure that trends in national emissions are consistently estimated

Chapter 8Quality Assurance and Quality Control  covers measurement standards, routine computational and completeness checks, and documentation and data archiving procedures to be applied to the inventory at the compilation stage.  describes a system of independent review and auditing that could be implemented by inventory agencies  covers only actions that inventory agencies could take in respect of their own inventories

Annex 1Conceptual Basis for Uncertainty Analysis  deals with the concepts that underlie the practical advice on uncertainties provided in the Chapters 2 to 8 of the main report (statistical concepts, sources of uncertainties, applications)

Annex 2Verification  discusses international and scientific aspects, options or tools for inventory verification  includes practical guidance for verification of emissions inventories

Annex 3Glossary  defines the terms of particular interest in the context of greenhouse gas inventories  summarises mathematical definitions of selected statistical terms for convenient reference

Key Source Category “A key source category is one that is prioritized within the national inventory system because its estimate has a significant influence on a country’s total inventory of direct greenhouse gases in terms of the absolute level of emissions, the trend in emissions, or both.”

Why do we need to identify key source categories in the national inventory?  inventory development is a resource intensive enterprise  in most cases, resources are limited and have to be prioritized  certain source categories are particularly significant in their contribution to the overall uncertainty of the inventory

“It is important to identify these key source categories so that the resources available for inventory preparation may be prioritized and the best possible estimates prepared for the most significant source categories.” …How do we identify Key Source Categories?

Key Source Category Analysis  Quantitative Approach – relationship between the level and trend of each source category’s emissions and total national emissions (Level and Trend Assessments)  Qualitative Approach – considers other criteria that are not easily assessed through a quantitative analysis.

Decision tree to identify key source categories No Yes No Are inventory data available for more than one year? Are country-specific uncertainty estimates available for each category estimate? Determine key categories using the Tier 2 Level and Trend Assessments, incorporating national uncertainty estimates and evaluating qualitative criteria Determine key categories using the Tier 1 Level Assessment and evaluating qualitative considerations Determine key categories using the Tier 1 Level and Trend Assessments and evaluating qualitative criteria Yes

Quantitative Approach -Tier 1 Method Level Assessment Equation 7.1 Source Category Level Assessment = Source Category Estimate / Total Estimate Lx,t = Ex,t / Et Where: Lx,t is the Level Assessment for source x in year t Source Category Estimate (Ex,t ) is the emission estimate of source category x in year t Total Estimate (Et) is the total inventory estimate in year t

Table 7.2: Spreadsheet for the Tier 1 Analysis – Level Assessment Column A – list of IPCC source categories (see Table 7.1, Suggested IPCC Source Categories) Column B – Direct Greenhouse Gas ( CO2, CH4, N2O, etc.) Column C – Base year emissions estimates from the national inventory data, in CO2-equivalent units Column D – Current year emissions estimates from the most recent national inventory, in CO2-equivalent units Column E: Level Assessment from Equation 7.1 Column F: Cumulative total of Column E

How to decide using Table 7.2? Any source category that meets the 95% threshold in any year should be identified as a key source category.

Tier 1 Analysis – Level Assessment (US Inventory) IPCC Source CategoriesDirect Greenhouse Gas Base Year Estimate Current Year Estimate Level Assessment Cumulative Total of LA CO 2 Emissions from Stationary Combustion - Coal CO Mobile Combustion – Road & OtherCO CO 2 Emissions from Stationary Combustion - Gas CO CO 2 Emissions from Stationary Combustion – Oil CO CH 4 Emissions from Solid Waste Disposal Sites CH Direct N 2 O Emissions from Agricultural SoilsN2ON2O Mobile Combustion: AircraftCO Fugitive Emissions from Oil and Gas Operations CH 4 Emissions from Enteric Fermentation in Domestic Livestock CH Indirect N 2 O Emissions from Nitrogen Used in Agriculture N2ON2O Fugitive Emissions from coal mining and handling CH CH 4 Emissions from Manure managementCH Mobile Combustion: Road and OtherN2ON2O Mobile Combustion: MarineCO …… TOTAL

Tier 1 Method Trend Assessment Equation 7.2 Source Category Trend Assessment = (Source Category Level Assessment) x  (Source Category Trend –Total Trend)  T x,t = L x,t *  [( E x,t - E x,o ) / E x,t ] - [(E t - E o )/ E t ]  Where: T x,t is the Trend Assessment which is the contribution of the source category to the overall inventory trend (absolute value) L x,t is the Level Assessment for source x in year t (Equation 7.1) E x,t and E x,o are the emissions estimates of source category x in years t and 0, respectively E t and E o are the total inventory estimates in years t and 0, respectively

Table 7.3: Spreadsheet for the Tier 1 Analysis – Trend Assessment Column A – list of IPCC source categories (see Table 7.1, Suggested IPCC Source Categories) Column B – Direct Greenhouse Gas ( CO2, CH4, N2O, etc.) Column C – Base year emissions estimates from the national inventory data, in CO2-equivalent units Column D – Current year emissions estimates from the most recent national inventory, in CO2-equivalent units Column E: Trend Assessment from Equation 7.2 recorded as an absolute number Column F: Percentage contribution to the total trend of the national inventory Column G: Cumulative Total of Column F

Tier 1 Analysis – Trend Assessment (US Inventory) IPCC Source CategoriesDirect Greenhouse Gas Base Year Estimate Current Year Estimate Trend Assessment % Contributio n to trend Cumulative Total CO 2 Emissions from Stationary Combustion - OilCO CO 2 Emissions from Stationary Combustion - GasCO Emissions from Subs. for Ozone Depleting substancesSeveral Fugitive Emissions from Coal Mining & handlingCH < Mobile Combustion: AviationCO < Mobile Combustion: Road & OtherCO < CH4 Emissions from Solid Waste Disposal SitesCH < Fugitive Emissions from Oil & Gas OperationsCH < Mobile Combustion: MarineCO < PFC Emissions from Aluminum ProductionPFC4.92.9< Mobile Combustion: Road & OtherN2ON2O < HFC-23 Emissions from HCFC-22 ManufactureHFC9.58.2< CH 4 Emissions from Enteric Fermentation in Livestock CH < Direct N 2 O Emissions from Agricultural SoilsN2ON2O < CO 2 Emissions from Stationary Combustion – CoalCO < N 2 O Emissions from Adipic Acid ProductionN2ON2O4.73.9< SF 6 from Magnesium ProductionSF < PFC, HFC & SF6 Emissions from semicon. manuf.several0.21.3< …… TOTAL

Table 7.A3. Source Category Analysis Summary (US Inventory) A IPCC Source Categories B Direct Green- house Gas C Key Source Category Flag D If Column C is Yes, Criteria for identifi- cation E Comments ENERGY SECTOR CO 2 Emissions from Stationary Combustion - Coal CO 2 YesLevel, Trend CO 2 Emissions from Stationary Combustion – Oil CO 2 YesLevel, Trend …… INDUSTRIAL SECTOR N 2 O Emissions from Adipic Acid Production N2ON2OYesTrend …… AGRICULTURE SECTOR ……

Qualitative Approaches to identify key source categories  Use of mitigation techniques and technologies  Expecting high emission growth  Categories with high uncertainty  Exhibiting unexpectedly low or high emissions Criteria to consider that are not easily assessed through a quantitative analysis:

Policy Relevance  GPG2000 does not revise or replace the 96GLs  Provides reference that complements and is consistent with the 96GLs: specific source categories are the same or can be traced back to categories in 96GLs uses same functional forms for the equations, or their equivalent allows for correction of any errors or deficiencies that have been identified in the 96GLs

Conclusions  it is through good practice guidance and uncertainty management that a sound basis can be provided to produce more reliable estimates of the magnitude of absolute and trend uncertainties in GHG inventories than has been achieved previously  whatever the level of complexity of the inventory, good practice provides improved understanding of how uncertainties may be managed to produce emissions estimates that are acceptable for the purposes of the UNFCCC (i.e. transparency, consistency, comparability, completeness and accuracy in inventories), and for the scientific work associated with GHG inventories.