2006 IPCC GUIDELINES FOR
NATIONAL GREENHOUSE GASINVENTORIESOVERVIEWOverview

Authors
Jim Penman (UK), Michael Gytarsky (Russia), Taka Hiraishi (Japan), William Irving (USA),and Thelma Krug (Brazil)

2

2006 IPCC Guidelines for National Greenhouse Gas Inventories

Overview

Contents
Overview
1

Introduction ............................................................................................................................................ 4

2

Coverage of the Guidelines .................................................................................................................... 53

Approach to developing the Guidelines ................................................................................................. 8

4

Structure of the Guidelines ..................................................................................................................... 95Specific developments in the 2006 IPCC Guidelines ........................................................................... 10

FiguresFigure 1

Main categories of emissions by sources and removals by sinks ........................................... 6

Figure 2

Example Decision Tree (for CH4 and N2O from Road Transport) ......................................... 9

TablesTable 1

Contents of 2006 Guidelines .................................................................................................. 5

Table 2

Gases for which GWP values are available in the TAR ......................................................... 7

Table 3

Additional gases for which GWP values are not available in the TAR .................................. 7

Table 4General structure of sectoral guidance chapters ................................................................... 102006 IPCC Guidelines for National Greenhouse Gas Inventories

3

Overview

1 INTRODUCTION
The 2006 IPCC Guidelines for National Greenhouse Gas Inventories (2006 IPCC Guidelines) provide
methodologies for estimating national inventories of anthropogenic emissions by sources and removals by sinksof greenhouse gases. The 2006 IPCC Guidelines were prepared in response to an invitation by the Parties to the
UNFCCC. They may assist Parties in fulfilling their commitments under the UNFCCC on reporting on
inventories of anthropogenic emissions by sources and removals by sinks of greenhouse gases not controlled by
the Montreal Protocol, as agreed by the Parties. The 2006 IPCC Guidelines are in five volumes. Volume 1
describes the basic steps in inventory development and offers the general guidance in greenhouse gas emissions
and removals estimates based on the authors’ understanding of accumulated experiences of countries over theperiod since the late 1980s, when national greenhouse gas inventories started to appear in significant numbers.
Volumes 2 to 5 offer the guidance for estimates in different sectors of economy.
The IPCC has previously developed the Revised 1996 IPCC Guidelines for National Greenhouse Gas
Inventories1 (1996 IPCC Guidelines), together with the Good Practice Guidance and Uncertainty Management
in National Greenhouse Gas Inventories2 (GPG2000) and the Good Practice Guidance for Land Use, Land-Use
Change and Forestry3 (GPG-LULUCF). Taken together, they provide internationally agreed4 methodologies thatcountries currently use to estimate greenhouse gas inventories to report to the United Nations Framework
Convention on Climate Change (UNFCCC). The three-volume 1996 IPCC Guidelines define the coverage of thenational inventory in terms of gases and categories of emissions by sources and removals by sinks, and the
GPG2000 and GPG-LULUCF provide additional guidance on choice of estimation methodology, improvementsof the methods, as well as advice on cross-cutting issues, including estimation of uncertainties, time seriesconsistency and quality assurance and quality control.
At its seventeenth session, held in New Delhi in 2002, the Subsidiary Body for Scientific and Technological
Advice (SBSTA) under the UNFCCC invited the IPCC to revise the 1996 IPCC Guidelines, taking into
consideration the relevant work under the Convention and the Kyoto Protocol5, with the aim of completing thework by early 2006.
In response to the UNFCCC’s invitation, the IPCC, at its 20th session in Paris, in February 2003, initiated aprocess that led to an agreement at its 21st session (in Vienna, November 2003) of Terms of Reference, Table ofContents and a Workplan6 for the 2006 IPCC Guidelines. The Workplan aimed to complete the task in time for
adoption and acceptance at the 25th session of the IPCC, in April 2006. The Terms of Reference specified thatthe revision should be based on, inter alia, the 1996 IPCC Guidelines, GPG2000, GPG-LULUCF, andexperiences from the UNFCCC technical inventory review process.

1

Intergovernmental Panel on Climate Change (IPCC) (1997). Houghton J.T., Meira Filho L.G., Lim B., Tréanton K.,
Mamaty I., Bonduki Y., Griggs D.J. and Callander B.A. (Eds). Revised 1996 IPCC Guidelines for National Greenhouse
Inventories. IPCC/OECD/IEA, Paris, France.

2

Intergovernmental Panel on Climate Change (IPCC) (2000). Penman J., Kruger D., Galbally I., Hiraishi T., Nyenzi B.,
Emmanuel S., Buendia L., Hoppaus R., Martinsen T., Meijer J., Miwa K., and Tanabe K. (Eds). Good Practice Guidanceand Uncertainty Management in National Greenhouse Gas Inventories. IPCC/OECD/IEA/IGES, Hayama, Japan.

3Intergovernmental Panel on Climate Change (IPCC) (2003). Penman J., Gytarsky M., Hiraishi T., Krug, T., Kruger D.,
Pipatti R., Buendia L., Miwa K., Ngara T., Tanabe K., and Wagner F (Eds). Good Practice Guidance for Land Use, landUse Change and Forestry IPCC/IGES, Hayama, Japan.

4

See the Report of the Fourth Session of the Subsidiary Body for Scientific and Technological Advice(FCCC/SBSTA/1996/20), paragraph 30; decisions 2/CP.3 and 3/CP.5 (UNFCCC reporting guidelines for preparation ofnational communications by Parties included in Annex I to the Convention, part I: UNFCCC reporting guidelines onannual inventories), decision 18/CP.8, revising the guidelines adopted under decisions 3/CP.5, and 17/CP.8 adopting
improved guidelines for the preparation of national communications from Parties not included in Annex I to theConvention, and subsequent decisions 13/CP.9 and Draft Decision /CP.10.

5Including, inter alia, work by the Subsidiary Body for Scientific and Technological Advice and the Subsidiary Body for
Implementation, and by the Consultative Group of Experts on National Communications from Parties not included in
Annex I to the Convention, and the technical review of greenhouse gas inventories of Annex I Parties.

6

The Terms of Reference, Table of Contents and Work plan can be found at http://www.ipcc-nggip.iges.or.jp/.

42006 IPCC Guidelines for National Greenhouse Gas Inventories

Overview

2 COVERAGE OF THE GUIDELINES
Table 1 shows the contents of the five volumes that make up the 2006 IPCC Guidelines. Estimation methods areprovided for the gases shown in Tables 2 and 3, and cover the categories shown in Figure 1. Reporting is
described in Chapter 8 of Volume 1. Coverage is complete for all greenhouse gases not covered by the Montreal
Protocol, for which the IPCC, at the time of writing, provided a global warming potential (GWP)7.
TABLE 1
CONTENTS OF 2006 GUIDELINES
Volumes

Chapters

1 - General Guidance andReporting

1.
2.
3.
4.
5.
6.
7.
8.

Introduction to the 2006 Guidelines
Approaches to Data Collection
Uncertainties
Methodological Choice and Identification of Key Categories
Time Series Consistency
Quality Assurance/Quality Control and Verification
Precursors and Indirect Emissions
Reporting Guidance and Tables

2 - Energy

1.
2.
3.
4.
5.
6.
1.
2.
3.
4.
5.
6.
7.
8.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.

Introduction
Stationary Combustion
Mobile Combustion
Fugitive Emissions
CO2 Transport, Injection and Geological Storage
Reference Approach
Introduction
Mineral Industry Emissions
Chemical Industry Emissions
Metal Industry Emissions
Non-Energy Products from Fuels and Solvent Use
Electronics Industry Emissions
Emissions of Fluorinated Substitutes for Ozone Depleting Substances
Other Product Manufacture and Use
Introduction
Generic Methodologies Applicable to Multiple Land-use Categories
Consistent Representation of Lands
Forest Land
Cropland
Grassland
Wetlands
Settlements
Other Land
Emissions from Livestock and Manure Management
N2O Emissions from Managed Soils, and CO2 Emissions from Limeand Urea Application
Harvested Wood Products
Introduction
Waste Generation, Composition and Management Data
Solid Waste Disposal
Biological Treatment of Solid Waste
Incineration and Open Burning of Waste
Wastewater Treatment and Discharge

3 - Industrial Processes andProduct Use

4 - Agriculture, Forestry andOther Land Use

5 - Waste

7

12.
1.
2.
3.
4.
5.
6.

Climate Change 2001: The Scientific Basis Contribution of Working Group I to the Third Assessment Report of the IPCC,(TAR), (ISBN 0521 80767 6), Section 6.12.2, Direct GWPs.

2006 IPCC Guidelines for National Greenhouse Gas Inventories

5Overview

Figure 1

Main categories of emissions by sources and removals by sinks

1A1

Energy Industries

1A2 Manufacturing Industries and Construction
1A3a Civil Aviation
1A3b Road Transportation

1A Fuel Combustion
Activities

1A3 Transport

1A3c Railways
1A3d Water-borne Navigation
1A3e Other Transportation

1A4 Other Sectors

1
ENERGY

1A5 Non-Specified
1B Fugitive
Emissions fromFuels

1B1 Solid Fuels
1B2

Oil and Natural Gas

1B3 Other Emissions from Energy Production
1C Carbon
DioxideTransport andStorage

1C1 Transport of CO2
1C2 Injections and Storage
1C3 Other

2 INDUSTRIALPROCESSES AND
PRODUCT USE

2AMineral Industry

2B

Chemical Industry

2C

Metal Industry

2D Non-Energy Products from Fuels and Solvent
Use
2E

Electronics Industry

2F Product Uses as Substitutes for Ozone Depleting Substances

National
Greenhouse
Gas
Inventory

2G Other Product Manufacture and Use
2H Other

3A1 Enteric Fermentation
3A Livestock

3A2 Manure Management
3B1 Forest Land

3 AGRICULTURE,
FORESTRY, AND
OTHER LAND USE

3B2 Cropland
3B3
3B LandGrassland

3B4 Wetlands
3B5 Settlements
3B6 Other Land

3C Aggregate Sources and Non-CO2 Emissions Sources on Land
3D Other

4A Solid Waste Disposal
4B Biological Treatment of Solid Waste

4 WASTE

4C Incineration and Open Burning of Waste
4D Wastewater Treatment and Discharge
4E Other

5 OTHER

6

5A Indirect N2O Emissions from the Atmospheric Deposition of Nitrogen in NOx and NH3
5B Other2006 IPCC Guidelines for National Greenhouse Gas Inventories

Overview

Volume 3 of the 2006 IPCC Guidelines also provides estimation methods and/or emission factors for somedirect greenhouse gases not covered by the Montreal Protocol for which GWP values were not available from the
IPCC at the time of writing (Table 3). These gases are sometimes used as substitutes for gases included in Table
2, for industrial and product applications. Until GWP values are made available from the IPCC, countries will be
unable to incorporate these gases in key category analysis (see Section 3 below) or include them in national total
GWP weighted emissions. However, optionally, countries may wish to provide estimates of these greenhousegases in mass units, using the methods provided in the 2006 IPCC Guidelines. Reporting tables are provided forthis purpose.

TABLE 2GASES FOR WHICH GWP VALUES ARE AVAILABLE IN THE TAR8
Name

SymbolCarbon Dioxide

CO2MethaneCH4

Nitrous Oxide

N2O

Hydrofluorocarbons

HFCs (e.g., HFC-23 (CHF3), HFC-134a (CH2FCF3), HFC-152a (CH3CHF2))

Perfluorocarbons

PFCs (CF4, C2F6, C3F8, C4F10, c-C4F8, C5F12, C6F14)

Sulphur Hexafluoride

SF6

Nitrogen Trifluoride

NF3

Trifluoromethyl Sulphur
Pentafluoride

SF5CF3

Halogenated Etherse.g., C4F9OC2H5, CHF2OCF2OC2F4OCHF2, CHF2OCF2OCHF2

Other halocarbons

e.g., CF3I, CH2Br2, CHCl3, CH3Cl, CH2Cl29

TABLE 3
ADDITIONAL GASES FOR WHICH GWP VALUES ARE NOT AVAILABLE IN THE TAR

C3F7C(O)C2F510
C7F16
C4F6
C5F8
c-C4F8O
The 2006 IPCC Guidelines contain links to information on methods used under other agreements andconventions11, for the estimation of emissions of tropospheric precursors which may be used to supplement thereporting of emissions and removals of greenhouse gases for which methods are provided here.

8

Third Assessment Report of the IPCC. See also footnote 7.

9

For these gases, emissions can be estimated following the methods described in Section 3.10.2 of Volume 3 if necessary
data are available, and then reported under sub-category 2B10 “Other”.

10

This gas is traded as Novec™612 which is a fluorinated ketone produced by 3M (Milbrath, 2002).

11

See, for example, Volume 1 Sections 7.1 and 7.2, where inventory developers are referred to the material developed by the
Task Force on Emission Inventories and Projections of the UNECE’s Convention on Long-Range Transboundary Air
Pollution for the purpose of estimating emissions of sulphur dioxide (SO2); carbon monoxide (CO); oxides of nitrogen(NOx); ammonia (NH3) and non-methane volatile organic compounds (NMVOCs).

2006 IPCC Guidelines for National Greenhouse Gas Inventories

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Overview

3 APPROACH TO DEVELOPING THE
GUIDELINES
The 2006 IPCC Guidelines are an evolutionary development starting from the 1996 IPCC Guidelines, GPG2000
and GPG-LULUCF. A fundamental shift in methodological approach would pose difficulties with time seriesconsistency in emissions and removals estimation, and incur additional costs, since countries and theinternational community have made significant investments in inventory systems. An evolutionary approachhelps ensure continuity, and allows for the incorporation of experiences with the existing guidelines, newscientific information, and the results of the UNFCCC review process. The most significant changes occur inVolume 4, which consolidates the approach to Land Use, Land-Use Change and Forestry (LULUCF) in GPGLULUCF and the Agriculture sector in GPG2000 into a single Agriculture, Forestry and Other Land Use(AFOLU) Volume. This, and other important developments and changes, are summarised in Section 5 below.
The 2006 IPCC Guidelines retain the definition of good practice that was introduced with GPG2000. Thisdefinition has gained general acceptance amongst countries as the basis for inventory development. According tothis definition, national inventories of anthropogenic greenhouse gas emissions and removals consistent withgood practice are those, which contain neither over- nor under-estimates so far as can be judged, and in which
uncertainties are reduced as far as practicable.
These requirements are intended to ensure that estimates of emissions by sources and removals by sinks, even if
uncertain, are bona fide estimates, in the sense of not containing any biases that could have been identified andeliminated, and that uncertainties have been reduced as far as practicable, given national circumstances. Estimatesof this type are presumably the best attainable, given current scientific knowledge and available resources.
The 2006 IPCC Guidelines generally provide advice on estimation methods at three levels of detail, from tier 1(the default method) to tier 3 (the most detailed method). The advice consists of mathematical specification of
the methods, information on emission factors or other parameters to use in generating the estimates, and sourcesof activity data to estimate the overall level of net emissions (emission by sources minus removals by sinks).
Properly implemented, all tiers are intended to provide unbiased estimates, and accuracy and precision should, ingeneral, improve from tier 1 to tier 3. The provision of different tiers enables inventory compilers to use methods
consistent with their resources and to focus their efforts on those categories of emissions and removals that
contribute most significantly to national emission totals and trends.
The 2006 IPCC Guidelines apply the tiered approach by means of decision trees (see the example in Figure 2).
A decision tree guides selection of the tier to use for estimating the category under consideration, given national
circumstances. National circumstances include the availability of required data, and contribution made by thecategory to total national emissions and removals and to their trend over time. The most important categories, interms of total national emissions and the trend, are called key categories12. Decision trees generally require tier 2
or tier 3 methods for key categories. The 2006 IPCC Guidelines provide for exceptions to this, where evidence
demonstrates that the expense of data collection would significantly jeopardize the resources available for
estimating other key categories.
The 2006 IPCC Guidelines also provide advice on; i) ensuring data collection is representative and time series
are consistent, ii) estimation of uncertainties at the category level, and for the inventory as a whole, iii) guidanceon quality assurance and quality control procedures to provide cross-checks during inventory compilation, and iv)
information to be documented, archived and reported to facilitate review and assessment of inventory estimates.
Reporting tables and worksheets for tier 1 methods are provided. The use of tiered methodologies and decision
trees and the cross cutting advice ensure that the finite resources available for inventory development andupdating are deployed most effectively, and that the inventory is checked and reported in a transparent manner.

12

8

In the GPG2000 and GPG-LULUCF these were called key sources, or key categories where there could be removals.

2006 IPCC Guidelines for National Greenhouse Gas Inventories

Overview

Figure 2

Example Decision Tree (for CH 4 and N 2 O from Road Transport)
Start

VKT byfuel and technology
type available?

Yes

Are
Country-specifictechnology based emission
factors available?

Yes

Use vehicle activity
based model andcountry-specificfactors e.g. COPERT.
Box 1: Tier 3

No

No

Can
you allocate
fuel data to vehicle
technology
types?

Use default factors
and disaggregation
by technology.

Yes

Box 2: Tier 2

No

Is this a key
category?

Yes

Collect data toallocate fuel totechnology types.

No

Use fuel-based
emission factors.
Box 3: Tier 1

4 STRUCTURE OF THE GUIDELINESThe structure of the 2006 IPCC Guidelines improves upon the structure of the 1996 IPCC Guidelines, GPG2000
and GPG-LULUCF in two respects.
Firstly, whereas a user of the 1996 IPCC Guidelines, GPG2000 and GPG-LULUCF may need to cross reference
between four or five volumes13 to make an emission or removal estimate, the 2006 IPCC Guidelines may requirecross referencing between two volumes: Volume 1 (General Guidance and Reporting), and the relevant sectoral
volume (one of Volume 2 (Energy), Volume 3 (Industrial Processes and Product Use), Volume 4 (Agriculture,
Forestry and Other Land Use), and Volume 5 (Waste)). This represents a considerable simplification.
Secondly, the 2006 IPCC Guidelines present Agriculture, Forestry and Other Land Use in a single volume, rather
than two volumes comprising Agriculture, on the one hand, and Land-use Change and Forestry on the other.
This allows for better integration of information on the pattern of land use and should facilitate more consistentuse of activity data (for example, fertilizer application), that affects both agriculture and other land uses, thus
reducing or avoiding the possibilities for double counting or omission.

13

That is, three volumes of the IPCC 1996 Guidelines plus at least one of GPG2000 or GPG-LULUCF.

2006 IPCC Guidelines for National Greenhouse Gas Inventories

9Overview

The 2006 IPCC Guidelines retain the standardised layout of methodological advice at the category level that was
introduced in GPG2000 and was maintained in GPG-LULUCF. Table 4 shows the general structure used foreach category. Any user familiar with GPG2000 and GPG-LULUCF should be able to shift to the 2006 IPCC
Guidelines without difficulty.
TABLE 4
GENERAL STRUCTURE OF SECTORAL GUIDANCE CHAPTERS••

Methodological Issueso Choice of Method, including decision trees and definition of tiers.
o Choice of Emission Factor
o Choice of Activity Datao Completenesso Developing a Consistent Time Series
Uncertainty Assessmento Emission Factor Uncertainties
o Activity Data Uncertainties•

Quality Assurance/Quality Control, Reporting and Documentation•

Worksheets

The previous IPCC inventory guidance has been reviewed and, where needed, clarified and expanded to improveits user friendliness. Across all the volumes, some additional categories have been identified and included. The
guidance focuses on inventory methodologies rather than on scientific discussions of the background material,
for which references are provided.

5 SPECIFIC DEVELOPMENTS IN THE 2006
IPCC GUIDELINES
The 2006 IPCC Guidelines are based on a thorough scientific review and a structural enhancement of the IPCC’s
inventory methodology across all categories, including the following specific developments:

Volume 1 (General Guidance and Reporting)•Introductory advice: A new section has been included, providing for an overview of greenhouse gas
inventories and the steps needed to prepare an inventory for the first time.

•

Extended advice on data collection: The 2006 IPCC Guidelines introduce systematic cross-cutting advice
on data collection from existing sources and by new activities, including design of measurement
programmes.

•

Key category analysis: General principles and guidance are provided. In the 2006 IPCC Guidelines, theintegration of Agriculture and LULUCF into the AFOLU volume has been addressed, and key category
analysis is better integrated across emission and removal categories.

Volume 2 (Energy)•

Treatment of CO2 capture and storage: These emissions are covered comprehensively, including fugitive
losses from CO2 capture and transport stages (which are estimated using conventional inventory approaches)plus any losses from carbon dioxide stored underground (estimated by a combination of modelling andmeasurement techniques, given the amounts injected - which would also be monitored for management
purposes). The inventory methods reflect the estimated actual emissions in the year in which they occur. The
inventory methods for geological CO2 capture, transport and storage (CCS) provided in Volume 2 areconsistent with the IPCC Special Report on Carbon Dioxide Capture and Storage (2005). Amounts of CO2
captured from combustion of biofuel, and subsequently injected into underground storage are included in theinventory as a negative emission. No distinction is made between any subsequent leakage of this CO2 andthat of CO2 from fossil sources.

•

Methane from abandoned coal mines: A methodology for estimating these emissions is included in the 2006
IPCC Guidelines for the first time.

10

2006 IPCC Guidelines for National Greenhouse Gas Inventories

Overview

Volume 3 (Industrial Processes and Product Use)•

New categories and new gases: The 2006 IPCC Guidelines have been expanded to include moremanufacturing sectors and product uses identified as sources of greenhouse gases. These include productionof lead, zinc, titanium dioxide, petrochemicals, and liquid crystal display (LCD) manufacturing. Additional
greenhouse gases identified in the IPCC Third Assessment Report are also included where anthropogenic
sources have been identified. These gases include nitrogen trifluoride (NF3), trifluoromethyl sulphur
pentafluoride (SF5CF3), and halogenated ethers.

•

Non-Energy Uses of Fossil Fuels: Guidance on demarcation with the energy sector has been improved, andemissions from non-energy uses of fossil fuels are now reported under Industrial Processes and Product Use,rather than in Energy. A method has been introduced for checking the completeness of carbon dioxide
emission estimates from the non-energy uses.

•

Actual emissions of fluorinated compounds: The potential emissions approach used as a tier 1 method in the1996 IPCC Guidelines is no longer considered appropriate, as it does not provide estimates of trueemissions, and is not compatible with higher tiers. The Tier 1 methods proposed in this volume are therefore
actual emission estimation methods, although these are often based on default activity data where better data
are not available. Simplified mass balance approaches have also been proposed in appropriate sectors, suchas refrigeration.

Volume 4 (Agriculture, Forestry and Other Land Use)•

Integration between agriculture and land use, land-use change and forestry: This integration removes thesomewhat arbitrary distinction between these categories in the previous guidance, and promotes consistentuse of data between them, especially for more detailed methods.

•

Managed land is used in these guidelines as a proxy for identifying anthropogenic emissions by sources andremovals by sinks. In most AFOLU sectors anthropogenic GHG emissions by source and removals by sinks
are defined as those occurring on managed land. The use of managed land as a proxy for anthropogenic
effects was adopted in the GPG-LULUCF. The preponderance of anthropogenic effects occurs on managed
lands and, from a practical standpoint, the information needed for inventory estimation is largely confined to
managed lands.

•

Consolidation of previously optional categories: Emissions by sources and removals by sinks associatedwith all fires on managed land are now estimated, removing the previous optional distinction between
wildfires and prescribed burning. This is consistent with the concept of managed land as a proxy for
identifying anthropogenic emissions by sources and removals by sinks, as discussed above. Wildfires andother disturbances on unmanaged land cannot, in general, be associated to an anthropogenic or natural cause,and hence are not included in the 2006 IPCC Guidelines, unless the disturbance is followed by a land-use
change. In this case, the land affected by disturbance is considered to be managed, and all the greenhousegas emissions by sources and removals by sinks associated to the fire and other events are now estimated,
irrespective of whether of a natural origin or not. Carbon dioxide emissions and removals associated withterrestrial carbon stocks in settlements and managed wetlands, which were previously optional, have been
incorporated into the main guidance.

•

Harvested wood products (HWP): The 2006 IPCC Guidelines provide detailed methods that can be used toinclude HWP in greenhouse gas inventories using any of the approaches that are currently under discussion
within the UNFCCC process.

•

Emissions from managed wetlands: The 2006 IPCC Guidelines now contain methods to estimate CO2
emissions due to land use change in wetlands. However, due to limited availability of scientific information,
methods for CH4 emissions are contained in an Appendix – Basis for future methodological development.

Volume 5 (Waste)•

Revised methodology for methane from landfills: The previous Tier 1 method, based on the maximum
potential release of methane in the year of placement, has been replaced by a simple first order decay modelthat provides the option to use data available from the UN and other sources. This approach includes
regional and country-specific defaults on waste generation, composition and management, and provides aconsistent basis for estimating greenhouse gas emissions across all tiers. This gives a more accurate timeseries for estimated emissions and should avoid the situation in which usage of landfill gas apparently
exceeds the amount generated in a particular year.

•

Carbon accumulation in landfills: This is provided as an output from the decay models, and can be relevant
for the estimation of HWP in AFOLU.

2006 IPCC Guidelines for National Greenhouse Gas Inventories

11

Overview•

Biological treatment and open burning of waste: Guidance on estimation of emissions from composting andbiogas facilities has been included to ensure a more complete coverage of sources.

Relevant to all volumes•

CO2 resulting from the emissions of other gases: The 2006 IPCC Guidelines estimate carbon emissions interms of the species which are emitted. Most of the carbon emitted as these non-CO2 species eventually
oxidises to CO2 in the atmosphere; and this amount can be estimated from the emissions estimates of the
non-CO2 gases. In some cases the emissions of these non-CO2 gases contain very small amounts of carbon
compared to the CO2 estimate and it may be more accurate to base the CO2 estimate on the total carbon. See
Volume 1 Section 7.2.1.5 for an approach to estimating these inputs of CO2 to the atmosphere. Examples are
fossil fuel combustion (where the emission factor is derived from the carbon content of the fuel) and a few
IPPU sectors where the carbon mass balance can be estimated much better than individual gases.

•

Treatment of nitrogen (N) deposition: The GPG2000 lists sources of anthropogenic nitrogen deposition that
subsequently give rise to anthropogenic emissions of nitrous oxide (N2O), but provides estimation methods
only for a subset of these, associated with agricultural sources of ammonia (NH3) and nitrogen oxides (NOx).
The 2006 IPCC Guidelines extend this approach to all significant sources of N deposition, including
agriculture, industrial and combustion sources, with the ultimate N2O emission attributed to the country
responsible for the nitrogen originally emitted.

•

Relationship to entity- or project level estimates: The Guidelines are intended to help prepare national
inventories of emissions by sources and removals by sinks. Nonetheless, the Guidelines can also be relevant
for estimating actual emissions or removals at the entity or project level.

122006 IPCC Guidelines for National Greenhouse Gas Inventories