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CHAPTER 7

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GOOD PRACTICE AND IMPLICATIONSFOR REPORTING

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Contents

2

5

7Good Practice Guidance and Implications for Reporting............................................................................. 7.3

6

7.1

Introduction .......................................................................................................................................... 7.3

7

7.2

Reporting and documentation .............................................................................................................. 7.3

8

7.2.1

Changes to reporting categories in the 2006 IPCC Guidelines .................................................... 7.3

9

7.2.2

Mapping the changes to categories in the 2006 IPCC Guidelines ................................................ 7.6

10

7.2.3

Documentation ............................................................................................................................. 7.7

11

7.2.4

Reporting tables ........................................................................................................................... 7.8

12

7.2.5

Worksheets ................................................................................................................................... 7.8

13

7.3

UnCertainties ....................................................................................................................................... 7.8

14

7.3.1

Overview of Uncertainty Analysis ............................................................................................... 7.8

15

7.3.2

Methods for quantifying uncertainty ............................................................................................ 7.9

16

7.4

Impact on key categories .................................................................................................................... 7.13

17

7.4.1

Overview of key category analysis ............................................................................................ 7.13

18

7.4.2

Key category analysis including the categories impacted by the Wetlands Supplement ........... 7.13

19

7.5

Completeness ..................................................................................................................................... 7.17

20

7.6

Time Series Consistency .................................................................................................................... 7.17

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7.6.1

Overview of time series issues ................................................................................................... 7.17

22

7.6.2

Methods for producing consistent time series ............................................................................ 7.18

23

7.7

Quality Assurance and Quality Control ............................................................................................. 7.19

24

7.7.1

Overview of quality issues ......................................................................................................... 7.19

25

7.7.2

Quality Assurance and Quality Control Methods....................................................................... 7.19

26

Annex 7 Worksheets .......................................................................................................................................... 7.20

27

References ...................................................................................................................................................... 7.21

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Figures

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Figure 7.1

Filling data gaps by multivariate statistical analysis andrecalculation of the time series of carbon in dead woodin the Netherlands national greenhouse gas inventory. .......................................................... 7.18

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Figure 7.2

Validation of the Forest DNDC model by comparison of modelledagainst measured values of aboveground biomass in Eucalyptus globulus in Australia (Miehle
et al. 2006). ............................................................................................................................ 7.19

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Figure 7.3

Validation of Ikonos satellite-derived land cover using an error matrix
comparing remote sensing-derived wetlands classes in Florida, USA against field observations(Chadwick 2011).................................................................................................................... 7.20

Tables38

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Table 7.1

Mapping between the categories and guidance in the 2006 IPCC Guidelines
and the changes to those introduced by the Wetlands Supplement. ......................................... 7.6

41

Table 7.2

Selection of wetlands with published uncertainties ............................................................... 7.11

42

Table 7.3

Suggested aggregation level of analysis for Approach 1 for afolu and waste sectors ............ 7.14

Equations43

44

Equation 7.1

Fractional uncertainty .............................................................................................................. 7.9

45Equation 7.2

Combining uncertainties – addition and subtraction ................................................................ 7.9

46

Equation 7.3

Combining uncertainties – multiplication ................................................................................ 7.9

47

Equation 7.4

Monte Carlo analysis – general form of a variable ................................................................ 7.12

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7.2

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7 GOOD PRACTICE GUIDANCE ANDIMPLICATIONS FOR REPORTING

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7.1

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2013 Supplement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories: Wetlands (Wetlands
Supplement) contains updated and new methodological guidance for greenhouse gas emissions and removals
from drained and rewetted peatlands and organic soils as well as from specific human-induced changes in coastal,inland mineral soil, and constructed wetlands. The methodological guidance is given in chapters 2 to 6:

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58

•

Cross-cutting guidance on organic soils (supplemental guidance to 2006 IPCC Guidelines, Chapter 2, on
generic methods relating to organic soils on all land-use categories, especially Forest Land, Cropland andGrassland)

59•

Rewetting and restoration of peatlands and other organic soils

60•Managed coastal wetlands

61•Managed inland mineral soil wetlands

62•

Constructed wetlands—wastewater treatment systems.

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The supplementary methodological guidance can introduce changes to the estimation and reporting of emission
and removals according to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories (hereafter 2006
IPCC Guidelines) in all land-use categories (forest land, cropland, grassland, wetlands, settlements and otherland) and of some sources of N2O emissions from managed land in the Agriculture, Forestry and Other Land Use(AFOLU) Sector as well as to CH4 and N2O emissions related to wastewater treatment (constructed wetlands) in
the Waste Sector. The changes come from more detailed methodologies to update the relevant
emissions/removals as well as from methodologies for categories not covered by the 2006 IPCC Guidelines. The
2013 Wetlands supplement maintains the 2006 IPCC approaches in estimation of the emissions and removals in
the AFOLU chapter. The general guidance in Volume 1 of the 2006 IPCC Guidelines is also applicable.

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This chapter gives good practice guidance relevant to the methodologies provided in Chapters 2 to 6 of this
Wetlands Supplement by addressing the following crosscutting issues:

74•

reporting including mapping the supplementary guidance into the categories of the 2006 IPCC Guidelines75•

uncertainty estimation76•

key category analysis

77•

completeness78•

time series consistency including guidance on estimation of historic emissions

79•

quality control and quality assurance.

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This chapter summarises the good practice guidance on the above-listed and crosscutting issues given in Volume
1 of the 2006 IPCC Guidelines but inventory experts need to refer to Volume 1 of the 2006 IPCC Guidelines forthe detailed guidance on the specific crosscutting issues. The crosscutting issues specific to the categories andmethodologies included in Chapters 2 to 6 are also addressed in those chapters. Here the category-specificinformation is summarized and complemented.

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7.2

REPORTING AND DOCUMENTATION

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7.2.1

Changes to reporting categories in the 2006 IPCC
Guidelines

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INTRODUCTION

Chapter 1 gives an overview of the purpose of the Wetlands Supplement as well as a description of its contents(Section 1.6.3) including the specific guidance provided and the linkage to the guidance in the 2006 IPCC
Guidelines. In Section 1.7 the estimation and reporting of emissions and removals from managed wetlands isaddressed through a case study and Table 1.5 provides the extension of reporting categories in the 2006 IPCC
Guidelines.

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In the sections below, the information presented in Chapter 1 is complemented with more details on the reporting
aspects of the Wetlands Supplement. The changes in the methodologies are addressed in the sections below basedon the Tier 1 methodologies in Chapters 2 to 6 to assess the need for changes to the reporting and backgroundinformation tables of the 2006 IPCC Guidelines (Volume 1, Chapter 8).

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7.2.1.1

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The guidance in Chapter 2 for estimation of CO2 emissions from organic soils implies changes for all land-use
categories compared to the guidance given in the 2006 IPCC Guidelines where the Tier 1 methodology was
simply a multiplication of areas of organic soils with appropriate emission factors by land-use category andclimate zone (boreal/temperate/tropical). For peat extraction also data on the nutrient status of the lands drained
impacted the emission factors. The supplementary methodology in Chapter 2 is using the same approach as in
the 2006 IPCC Guidelines and no changes in the reporting tables or background tables in the 2006 IPCC
Guidelines are need due to these changes. The detailed information on the activity data and emission factors aswell as other parameters used in the estimation should be provided in the national inventory report.

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The 2006 IPCC Guidelines did not provide a methodology for the estimation of CH4 emissions associated withdrainage whereas Chapter 2 provides a methodology to address CH4 emissions from ditches. Otherwise CH4
emissions from drained organic soils are assumed negligible. The estimation of the CH4 emissions from ditches
requires data on ditch width and ditch spacing. This information is in some cases needed by peatland type (raised
bog/fen or blanket bog). These emissions could be reported under the specific land-use categories where
drainage occurs or alternatively under Category 3C8 Other Non-CO2 GHG emissions not included elsewhere.

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The methodology for N2O emissions from drainage is the same as in the 2006 IPCC Guidelines but the default
emissions factors are updated. In accordance with the 2006 IPCC Guidelines the N2O emissions from drainage
of organic soils should be reported as aggregated to N2O emissions from managed soils and, if data available, theemissions can be provided by land-use category. The N2O emissions from drainage/management of histosols arereported under Category 3C4 Direct N2O Emissions from Managed Soils.

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The AFOLU reporting tables in the 2006 IPCC Guidelines do not require changes due to the changes insupplementary methodology provided for drainage of organic soils. The worksheets addressing the calculationsof all greenhouse gas emissions from drainage of organic soils will however be extended to take into accountchanges in methodologies as well as changes in the subdivision at which the updated emission factors areprovided.

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For easy assessment of all greenhouse gas emissions associated with drainage, it is good practice to provide asummary of all greenhouse gas from drainage by land-use category in the national inventory report.

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Extended background tables and worksheets will be only included in the Second Order Draft.

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7.2.1.2

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Guidance on CO2, CH4 and N2O emissions from rewetting is not included in the 2006 IPCC Guidelines. Chapter
3 of this Wetlands Supplement provides this guidance. Tier 1 methodologies for rewetted peatlands and organicsoils are given for CO2 emissions/removals from soils including moss and grass vegetation and dead organic
matter and also for dissolved organic carbon pools. The guidance addressing CH4 emissions cover emissions
from the rewetting as well as burning of biomass and peat on rewetted lands. N2O emissions from rewetted soils
are considered insignificant and assumed to be zero under Tier 1. When rewetted lands contain perennial woody
vegetation, the guidance in the 2006 IPCC Guidelines, Sections 4.2, 4.4, 4.5 and 4.6, should be used.

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The reporting of rewetting would be dependent on the resultant land-use after the rewetting. The rewetted land
could remain in the same land-use category, e.g. when agricultural land with organic soil is rewetted to form agrazing marsh. The rewetting could also involve a land-use change, e.g. when a forest with organic soil isrewetted and the tree coverage declines below the threshold of the national forest definition. It is good practice
to report emissions/removals from rewetting in the relevant land-use categories.

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Biomass and peat burning on rewetted lands would be reported in the 2006 IPCC Guidelines Table 3.4 AFOLU
Background Table Biomass Burning under relevant sub-categories under Category 3C1 Emissions from biomassburning. The table could be modified so that it would be possible to specify the subcategory for which theburning is reported. Also, emissions from burning soils (peat) should be reported under relevant sub-categories
under Category 3C1. The definition of Category 3C1 in Table 8.2 in Chapter 8, Volume 1 of the 2006 IPCC
Guidelines needs to be extended accordingly.

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Extended background tables and worksheets will be only included in the Second Order Draft.

7.4

CO 2 , CH 4 AND N 2 O EMISSIO NS FRO M ORGANIC SOILSR EWETTINGDRAFT 2013 Wetlands Supplement

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7.2.1.3

C OASTAL WETLANDS AND INLAND MINERAL SOIL
WETLANDS

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Guidance on CO2, CH4 and N2O emissions from managed coastal wetlands and inland mineral soil wetlands is
not included in the 2006 IPCC Guidelines. Chapters 4 and 5 of this Wetlands Supplement provide this guidance.

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Guidance in Chapter 4 (Coastal wetlands) is provided in three discrete sections that cover Management Changes
in Coastal Wetlands (Section 4.3), Drainage of Coastal Wetlands (Section 4.4), Rewetting and Restoration of
Coastal Wetlands (Section 4.5), and as defined in Table 4.1. This chapter covers coastal wetlands that have beencleared or degraded, restored, or created, and where resource extraction occurs with little or no apparent
degradation (e.g., selective logging of mangrove trees). New methods are presented for soil carbon Tier 1 level
estimation whereas methods for biomass, dead organic matter and non-CO2 emissions follow those of previous
2006 IPCC guidance.

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In Chapter 5 (Inland mineral soil wetlands), guidance and methodologies mainly follow the 2006 IPCC
Guidelines, in particular the generic guidance given in Volume 4 Chapter 2. Chapter 5 provides additional
information to be used in applying the methods in the 2006 IPCC Guidelines and should be read in conjunction
with Volume 4 of the 2006 IPCC Guidelines. Management changes that affect CO2 and non-CO2 (CH4 and N2O)
emissions in inland mineral soil wetlands include water level management as well as activities that impact
vegetation (such as grazing, vegetation removal, and cultivation, nutrient amendments). Emissions from these
activities can be estimated with guidance provided in Chapter 5. Specifically, new default soil C stock data areprovided and an emission change factor approach is presented for estimating changes in CO2, CH4 and N2Oemissions from activities including restoration and drainage.

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These wetlands can occur in any of the six IPCC land-use categories. For example, a mangrove or riverine
wetland with trees may be classified as a forest, while a marsh may be used for grazing and classified as
grassland. The precise details of this classification are specific to each country so it is not possible to say exactly
how a coastal wetlands or inland wetland on mineral soil may be classified. This guidance applies to all coastal
wetlands and inland wetlands on mineral soils, however they are classified. The classification is important whenreporting these emissions, and there is no intention to change in any way how land is classified, however there
may be a need to sub-divide some land types to reflect differing management actions.

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Extended background tables and worksheets will be only included in the Second Order Draft.

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7.2.1.4

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Supplementary guidance on CH4 and N2O emissions from wastewater treatment and discharge is provided in
Chapter 6 on Constructed Wetlands. Constructed wetland systems are fully human-made wetlands for
wastewater treatment, which apply various technological designs, using natural wetland processes, associatedwith wetland hydrology, soils, microbes and plants. Thus, constructed wetlands are engineered systems that havebeen designed and constructed to utilize the natural processes involving wetland vegetation, soils, and theirassociated microbial assemblages to assist in treating wastewater. Methodologies are based on the load ofnitrogen and organic carbon into the systems. The CH4 emissions are calculated based on the conversion of
biological or chemical oxygen demand data and correction factors related to the flows in these constructedwetlands (free water surface, vertical subsurface flow and horizontal subsurface flow). The N2O emissions arecalculated based on the amount of nitrogen in the wastewater.

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Reporting of CH4 and N2O emission from constructed wetlands will be done under category 4D Wastewater
treatment and discharge. The emissions will be divided into Categories 4D1 Domestic wastewater treatment anddischarge and 4D2 Industrial Wastewater treatment and discharge according to source of wastewater treated in
the constructed wetlands.

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The areas of constructed wetlands should be reported as part of settlements. If the establishment of theconstructed wetland involves a land use conversion, the area changes should be reported under the specific landuse categories and the notation key “IE” should be used for the CH4 and N2O emissions. Any changes in carbon
stocks due to the land-use conversion, e.g. due to cutting of trees or removing of other vegetation, should bereported under land converted to settlements.

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Extended background tables and worksheets will be only included in the Second Order Draft.

C ONSTRUCTED WETLANDS

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7.2.2

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Mapping the changes to categories in the 2006 IPCC
Guidelines

Table 7.1 shows how the supplementary guidance and new categories introduced in the Wetlands Supplement arelinked to the guidance and categories in the 2006 IPCC Guidelines. This summarises the descriptions given in
the above sections on the changes introduced.

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TABLE 7.1
MAPPING BETWEEN THE CATEGORIES AND GUIDANCE IN THE 2006 IPCC GUIDELINES AND THE CHANGES TO THOSEINTRODUCED BY THE WETLANDS SUPPLEMENT.
Source ofemissions/sink forremovals

2006 IPCC Guidelines
Category

Wetlands Supplement

Guidance byCategory

Guidance byDrainage of organic soils
CO2

CH4

3B1 to 3B6
Forest land,
Cropland, Grassland,
Wetlands,
Settlements andOther landCategory 3B4ai
Peatlands remaining
peatlands

•

-

-

•
•

land-usecategory, forwetlands
specific topeat
extraction
climate zone
nutrient
statusforpeatlands

3B1 to 3B6
Forest land, Cropland,
Grassland, Wetlands,
Settlements and Other landCategory 3B4ai renamed as
Peat extraction lands
remaining peat extraction
lands, respective change to
3B4bi

•

3B1 to 3B6
Forest land, Cropland,
Grassland, Wetlands,
Settlements and Other landor 3C8

•

•
•

•
•

•

N2O

3C4

•

drainedorganic soils

•

3C4

•

land-usecategoryclimate zone
drainage classland-usecategoryclimate zone
peatland type((bog or fen,tropical peat)
ditch
area
(width, spacing
betweenditched)land-usecategoryclimate zone

Rewetting of peatlands and organic soils
CO2,
CH4 and
N2O--

3B1 to 3B6
Forest land, Cropland,
Grassland, Wetlands,
Settlements and Other land
Subcategories for rewetted
land remaining rewetted
lands and lands converted torewetted lands should be
introduced for the land-use
categories under which theactivity takes place.

••climate zone
peatlandtype(bog or fen,tropical peat)--

3B4aiii (Other wetlands
remaining wetlands)or
3B4biii (Land converted toother wetlands)•climatezone/region
vegetation typesalinity (whereapplicable/avail
able)

Coastal Wetlands
CO2,
CH4 and
N2O

7.6

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management
activity
includingrestoredanddrained•climatezone/region
levelofinundation(permanent andseasonal)
management
activity(restored,
createdordrained)Inland Mineral Soil Wetlands
CO2,
CH4 and
N2O--

3B4aiii (Other wetlands
remaining wetlands)or
3B4biii (Land converted toother wetlands)••

Constructed wetlands
CH4,
N2O

-

-

4 D Wastewater treatment
and discharge

•

CO2

3B5

No specificguidance but C
stock changes
from land-use
change coveredby the general
methodologies

3B5

No specificguidance but C
stock changes fromland-use change
covered by thegeneralmethodologies in
the 2006 IPCC
Guidelines

BOD/COD load
and technologyoftheconstructedwetland (type of
flow)

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7.2.3

Documentation

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Chapter 8 in Volume 1 of the 2006 IPCC Guidelines provides guidance on reporting complete, consistent andtransparent national greenhouse gas inventories. Detailed guidance on documentation relevant to the
supplementary guidance provided in this report is provided in Chapters 2 to 6.

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Reporting in accordance with the Wetlands Supplement involves combining guidance from two sets guidance,
this Supplement and the 2006 IPCC Guidelines. The estimation of emissions and removals requires in somecases a combination of methodologies which, if care is not taken, can lead to double-counting or omission ofemissions or removals. The reporting of emissions and removals from specific activities, e.g. rewetting anddrainage, is disaggregated among land-use categories and/or generic categories for reporting of non-CO2
emissions. National circumstances will also affect the reporting much. In some countries the categories will havea significant impact on the national total emissions, in others they will be almost non-existent.

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Transparent reporting will require that the following generic issues are documented in the national inventory
report:

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•

a summary of the areas and emissions by land-use category and gas for organic soils, rewetting, coastal
wetlands, inland mineral soil wetlands and constructed wetlands;

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•

information on how completeness has been assessed and double-counting avoided for reporting of CO2
emissions when methodologies based on flux measurements and stock change methods are combined for a
specific activity or land-use category as well as related to reporting of dissolved organic carbon.

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7.2.4

Reporting tables

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The Wetlands Supplement does not impact the Reporting Tables in Annex 8A.2 of Volume 1 of the 2006 IPCC
Guidelines.

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The background tables included in Annex 8A.2 will be extended to take into account the changes introduced by
the Wetlands Supplement (see sections above) and will be provided in Annex 7 in the Second Order Draft of the
Wetlands Supplement.

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7.2.5

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Annex 7 provides also worksheets for each sub-category that can be used to estimate emissions based on Tier 1
methods and appropriate emission/stock change factors and activity data.

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The worksheets will be provided in the Second Order Draft.

Worksheets

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7.3

UNCERTAINTIES

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7.3.1

Overview of Uncertainty Analysis

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Uncertainty is an expression of the degree to which the value of a variable is unknown (IPCC 2007). In
greenhouse gas inventories, uncertainty derives from quantifiable errors and variation in methods and data.
Because of uncertainty, the true value of a variable is sometimes not known, but it is possible to estimate thepossible range of values of the variable.

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For greenhouse gas inventories, quantification of uncertainty is important because it allows inventory agencies toascertain if estimated changes in greenhouse gas emissions and removals over time are larger than theuncertainty or range of possible estimates for an individual year. In wetlands, the magnitude of carbon stocks areoften much larger than annual changes, so large uncertainties in carbon stock estimates may make it difficult todetermine if estimated annual changes are real or a result of uncertainty. In this way, uncertainty analysis can
indicate areas for future improvement of inventory methods.

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In greenhouse gas inventories, major quantifiable sources of uncertainty include:245•

field measurement errors

246•

remote sensing inaccuracies

247•

missing or incomplete data series

248•

misreporting or misclassification249•

data bias or unrepresentative sampling250•

random sampling error

251•

spatial variation

252•

spatial or temporal autocorrelation

253•

model inaccuracies

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Uncertainty analysis generally proceeds through these steps:

255•

Identification of primary sources of uncertainty.

256•

Estimation of uncertainties of individual variables.

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•

Combination of individual variable uncertainties into total estimates of emissions or removals for a key
category or a land-use category for a geographic area.

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This section summarizes scientific methods (approaches) for each of these steps for the three tiers of greenhousegas inventory methods. It summarizes material from the 2006 IPCC Guidelines, including Volume 1, Chapter 3(Frey et al. 2006) and Volume 4, Chapter 7, and summarizes any new methods for the wetlands sub-categories
described in Chapters 2 to 6 of this Wetlands Supplement. This section aims to summarize new methods specific

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to the Wetlands Supplement and assess them across the wetlands subtypes. To the extent possible, it provides
published examples that illustrate new methods. Inventory compilers should consult the detailed information in
the 2006 IPCC Guidelines and this Wetlands Supplement.

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7.3.2

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The measure of uncertainty for national greenhouse gas inventories is the 95% confidence interval (CI). It isgood practice to report the 95% CI for individual variables, including activity data, emissions factors, biomass
densities, other parameters, and for total greenhouse gas emissions or removals from a key category or a land-use
category for a geographic area.

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Approach 1 - Use the measures of uncertainty given in the default tables in this Wetlands Supplement and the2006 IPCC Guidelines for individual variables. To combine individual variable uncertainties into total estimatesof emissions or removals for a key category or a land-use category for a geographic area, use basic uncertainty
combination methods (Mandel 1984), identified in Chapter 3 (Frey et al. 2006) of Volume 1 of the 2006 IPCC
Guidelines.

Methods for quantifying uncertainty

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278

EQUATION 7.1
FRACTIONAL UNCERTAINTY

279
280

Where:

281

Ui =uncertainty of a variable expressed as a fraction, from 0 to 1.0, of the mean of the variable

282

CIi =

95% confidence interval of the variable

283

µi =

mean value of the variable

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286

EQUATION 7.2
COMBINING UNCERTAINTIES – ADDITION AND SUBTRACTION

287
288

Where:

289

Utotal =fractional uncertainty of the sum of the variables

290

Ui =

uncertainty of a variable expressed as a fraction, from 0 to 1.0, of the mean of the variable291

xi = value of a variable; xi < 0 for subtraction

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EQUATION 7.3
COMBINING UNCERTAINTIES – MULTIPLICATION

295
296

Where:

297

Utotal =fractional uncertainty of the product of a set of variables

298

Ui =

uncertainty of a variable expressed as a fraction, from 0 to 1.0, of the mean of the variable

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Refer to the 2006 IPCC Guidelines (Frey et al. 2006) for detailed steps of basic uncertainty combination,
including calculation of uncertainties of temporal trends.

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This Wetlands Supplement presents guidance to take into consideration the sources of uncertainty, either in
activity data or emissions factors that are important specifically for wetlands and organic soils. The definitions ofwetland sub-categories and delineation of their surface areas can, by themselves, be sources of uncertainty.
While the 2006 IPCC Guidelines generally stratified land-use categories by ecological zone (Aalde et al. 2006)
or climate zone, this Wetlands Supplement can stratify wetland sub-categories by other properties. Sources of
uncertainty and new tables that provide inventory compilers with default uncertainty values include:

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310

•

Organic soils – Surface areas and emissions factors are a function of drainage class, which requires
estimates of the depth of the water table. Emissions from drainage ditches area is a function of the width andspacing of ditches.

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 Table 2.1 - Tier 1 CO2 emission/removal factors for organic soils in all land-use categories

312 Table 2.3 - Tier 1 CH4 emission/removal factors for organic soils in all land-use categories

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 Table 2.5 - Tier 1 N2O emission/removal factors for organic soils in all land-use categories

314•

Rewetted peatlands – Surface areas are a function of time from rewetting.

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 Table 3.3 - Default DOC emission factors for rewetted peatlands and organic soils

316

 Table 3.4 - Default emission factors for CH4 from rewetted peatlands and organic soils

317•

Coastal wetlands

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 Table 4.3 - Default values for carbon stored in coastal wetlands (SOCREF) based upon average carbon
density measured in top 1 m

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 Table 4.4 - Ratio of below-ground baiomass to above-ground biomass (R)

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 Table 4.5 - Default biomass conversion and expansion factors (BCEF), tonnes biomass (m3 of wood
volume)-1 (IPCC 2006)323

 Table 4.6 - Default values for above-ground biomass of mangrove and tidal salt marsh wetlands324 Table 4.7 - Default values for above-ground growth in mangrove and tidal salt marsh wetlands

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 Table 4.8 - Default values for above-ground biomass and net growth of seagrasses326

 Table 4.9 - Tier 1 Default values for dead wood and litter carbon stocks

327
328

 Table 4.11 - Emission factors for coastal wetland soils changed through aquaculture, salt production or
extraction329

 Table 4.12 - Emission factors for CH4 from coastal wetlands with altered Hydrology330

 Table 4.13 - Emission factors for N2O emission from coastal wetlands331

 Table 4.14 - Annual Emission Factors (EF) for Drained Soils for Tier 1 estimation332

 Table 4.15 - Relative Stock Change Factors for Drained Coastal Wetlands for Tier 1 level estimation333

 Table 4.16 - Annual removal factors for rewetted and restored soils for tier 1 estimation334

 Table 4.17 - Emission factors for CH4 from “intact” coastal wetlands for Tier 1 estimation

335•

Inland mineral soil wetlands – Emissions are a function of time under management.

336

 Table 5.1 - Default reference soil organic carbon stocks for IMS wetlands337

 Table 5.2 - Default CH4 emission factors for permanently inundated IMS wetlands338

 Table 5.3 - Default CH4 emission factors for seasonally inundated IMS wetlands339

 Table 5.4 - Emission factors for estimating N2O emissions from IMS wetlands

340

 Table 5.5 - Emission factors due to drainage or restoration of IMS wetlands (to be completed)341

 Table 5.6 - Soil CO2 emission factors for IMS wetlands to be used in Equation 5.4

342
343
344
345
346
347

•

7.10

Constructed wetlands – Emissions estimates require maximum CH4 producing potential, vegetation, andtemperature correction factors, human population (for estimating wastewater flow), and protein consumption(for estimating N2O emissions). Other sources of uncertainty include the degrees to which wastewater istreated in constructed wetlands or in semi-natural treatment wetlands, the fraction of organics that isconverted anaerobically to CH4 during wastewater collection, and the amount of industrial organic wastefrom small or medium scale industries that is discharged into constructed wetlands.

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 Table 6.5 - Default uncertainty ranges for domestic and industrial wastewater349

 Table 6.7 - Nitrous oxide methodology default uncertainties

350
351
352
353
354

It is good practice to use measures of uncertainty specific to a country or an ecosystem type, when available. Usepublished uncertainty estimates for similar ecosystems when country-specific estimates are not available. To
combine individual variable uncertainties into total estimates of emissions or removals for a key category of aland-use category for a geographic area, use Equations 7.1, 7.2, and 7.3. Table 7.2 lists a selection of wetlands
with published data for individual variables and examples of combination of variables.
TABLE 7.2
SELECTION OF WETLANDS WITH PUBLISHED UNCERTAINTIESContinent

AfricaAsia

North America

South America

GlobalCountry

WetlandReference

Botswana

Okavango Delta

Mladenov et al. 2005

Madagascar

estuary

Ralison et al. 2008

Senegalestuary area

Sakho et al. 2011

China

constructed wetland

Chen et al. 2011

Indo-Pacificmangroves

Donato et al. 2011

Indonesia

peat swamps and oil palms

Murdiyarso et al. 2010

Canadarestored wetlands

Badiou et al. 2011

Costa Rica

tropical inland wetlands

Bernal and Mitsch 2008

USA

streams and rivers

Butman and Raymond 2011

Argentina

river marsh

Vicari et al. 2011

BrazilPantanal

Schöngart et al. 2011

Peru

Amazonian peatland

Lähteenoja et al. 2012

Globalcoastal ecosystems

Mcleod et al. 2011

Globalfreshwater wetlands

Kayranli et al. 2010

Globalfreshwater wetlands methane

Bastviken et al. 2011

Globalrestored wetlands

Moreno-Mateos et al. 2012

Globalwetlands carbon and methane

Mitsch et al. 2010

355
356

Approaches to reducing uncertainty for the wetlands sub-categories in the Wetlands Supplement include:

357
358
359
360

•

Organic soils – Use spatially disaggregated CO2 flux measurements to develop local emission factors,
correcting for carbon losses through leaching of dissolved organic carbon or runoff. For emissions estimatesin boreal zones, include winter emissions, which can account for 10-30% of net annual emissions (Alm et al.
1999).

361
362•

Rewetted peatlands – CO2 and CH4 emissions are often a function of present vegetation composition andprevious land use history, so stratification of an area by these properties can improve emissions estimates.

363
364

•

Coastal wetlands – More detailed stratification of land by drainage and other management systems canimprove emissions estimates.

365•

Inland mineral soil wetlands – No new uncertainty issues identified.

366•

Constructed wetlands – No new uncertainty issues identified.

367
368
369
370
371

Approach 2 – For individual variables, calculate the 95% CI from the PDF of measurements of each variable.
Derive the PDF from a random sample. Capture the principal forms of spatial and temporal variation in thesample or calculate different PDFs for the principal spatial and temporal strata.) The 2006 IPCC Guidelines,
Volume 1, Chapter 3, Section 2.2.4 (Frey et al. 2006), provide methods to develop PDFs.

372
373
374

To combine individual variable uncertainties into total estimates of emissions or removals for a land-use
category or a geographic area, use the Monte Carlo method (Metropolis and Ulam 1949), identified by the 2006
IPCC Guidelines (Frey et al. 2006) as Approach 2. The Monte Carlo method is a statistical technique that

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quantifies the uncertainty of a variable based on a large number of randomized realizations of the value of thevariable based on its mean value, the standard error of the mean, and a PDF of the standard errors.

377
378
379
380
381
382
383

For example, the diameter at a height of 1.3 m of a tree (dbh) is an essential variable in estimating its carbon mass.
In a typical forest inventory, a person measures the tree once and records the measurement. If the measurement
were immediately repeated, the result may be slightly different due to the shape of the trunk, how the diametertape drapes around the trunk, where the person estimates the 1.3 m height for measurement, possible errors intranscribing the value, and other factors. Repeating the measurement 100 or 1000 times would generate a PDF
that might typically take the form of a normal distribution. The 95% CI of the distribution is a measure of theuncertainty of the dbh measurement.

384
385
386
387
388

Monte Carlo analysis consists of running a calculation for a statistically significant number of replications,typically 100 to 10 000, producing a probability density function of the result, and calculating the 95% CI of the
PDF. For any equation, the Monte Carlo form of a variable (Equation 7.4) can replace all the variables in theequation. The large number of realizations of the result effectively combines the uncertainties of individual
variables.

389
390

EQUATION 7.4
MONTE CARLO ANALYSIS – GENERAL FORM OF A VARIABLE

x i = meanx + (randomi × SE x )

391
392

Where:

393

xi = value of realization i of a variable,

394

i=

statistically significant number of realizations, typically 100 – 10 000

395

meanx =

mean value of a variable

396
397

randomi = random number for realization i, from -1 to 1, taken from a set of random numbers that form aprobability distribution function specific to the variable

398

SEx =

standard error of the mean value of the variable

399
400
401
402
403

Refer to the 2006 IPCC Guidelines (Frey et al. 2006) for detailed steps of Monte Carlo analysis, including
selection of an appropriate PDF for a variable and its random numbers. Inventory agencies and scientists havequantified uncertainty in greenhouse gas inventories in a range of cases, including the national inventories ofAustria (Winiwarter and Muik 2010), Finland (Monni et al. 2007), and the Netherlands (Ramírez et al. 2008) andhigh-biomass ecosystems in California, USA (Gonzalez et al. 2010) and Canada (Kurz et al. 2008).

404

Approaches to reducing uncertainty for the wetlands sub-categories in the Wetlands Supplement include:

405
406
407
408

•

Organic soils – Quantification of impacts of land-use and management on emissions can improve emissions
estimates. Examples include organic matter additions to agricultural land that can increase substrate supply
for methane production in ditches, short-term pulses of ditch CH4 emission associated with land-use change,
and nutrient-enriched soils that are a legacy of past land-use.

409
410
411

•

Rewetted peatlands – Determination of spatial variation of peat type and depth, vegetation composition,soil temperature, mean water table depth, the provision by vegetation of substrates for CH4 production, andtransport by vegetation of CH4 from saturated soil to the atmosphere can improve emissions estimates.

412
413

•

Coastal wetlands – Quantification of the effects of coastal grassland management, including grazing, fire,
liming, and fertilization, can improve emissions estimates.

414•

Inland mineral soil wetlands – No new uncertainty issues identified.

415•

Constructed wetlands – Provide separate estimates for anaerobic and aerobic constructed wetlands.

416

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7.4

IMPACT ON KEY CATEGORIES

418

7.4.1

Overview of key category analysis

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420
421
422
423
424
425
426
427
428

Methodological choice for individual source and sink categories is important in managing overall inventory
uncertainty. Generally, inventory uncertainty is lower when emissions and removals are estimated using the mostrigorous methods provided for each category or subcategory in the sectoral volumes of these Guidelines.
However, these methods generally require more extensive resources for data collection, so it may not be feasible
to use more rigorous method for every category of emissions and removals. It is therefore good practice toidentify those categories that have the greatest contribution to overall inventory uncertainty in order to make themost efficient use of available resources. By identifying these key categories in the national inventory, inventory
compilers can prioritize their efforts and improve their overall estimates. The purpose, general rules andapproaches for the key category analysis of the whole greenhouse gas inventory are presented in Chapter 4 ofVolume 1 of the 2006 IPCC Guidelines.

429
430

According to Section 4.2 in Volume 1 of the 2006 IPCC Guidelines the general rules for performing the key
category analysis are

431
432

•

The key category analysis should be performed at the level of IPCC categories or subcategories at which the
IPCC methods and decision trees are provided.

433
434

•

Each greenhouse gas emitted from each category should be considered separately, unless there are specificmethodological reasons for treating gases collectively.

435
436

•

Emissions and removals from a category should also be considered separately, where possible and relevantto the methodology used.

437
438
439

The Table 4.1 in Section 4.2 in Volume 1 of the 2006 IPCC Guidelines also gives a recommended level at which
the key category analysis should be performed. Countries may however choose to perform the quantitative
analysis at a more disaggregated level than suggested.

440
441
442
443
444
445
446
447
448

The key category analyses are performed using two approaches. Approach 1 is based on level and trend
assessments. In the level assessment, categories of the inventory are listed in the order of absolute values of theemissions or removals, and the largest categories contributing to 95 per cent of the total emissions are consideredas key categories. The trend assessment analyses the contribution of a category to the trend as well as if the trendof the category is significantly different from the trend of the inventory. The categories contributing most to thetrend and which add up to contributing 95 per cent to the trend are considered key categories. Approach 2 isbased on similar assessments but the results of the uncertainty analysis are taken into account. The mostsignificant categories contributing together 90 per cent to the uncertainties of the total emissions or the trend areconsidered key categories.

449

7.4.2

450

Key category analysis including the categories
impacted by the Wetlands Supplement

451
452
453
454
455
456

The suggested level for CO2 emissions (carbon stock changes) reported under the land-use categories in the
AFOLU Sector according to Table 4.1 in Volume 1 of the 2006 IPCC Guidelines is to divide the emissions or
removals for each land-use category to lands remaining in the category and lands converted to it. In addition, theinventory compilers should determine which pools and subcategories are significant. This approach is sensible,
as the CO2 emissions/removals from the land-use categories are generally estimated using the same or similar
generic methodologies and also the same activity data (area data).

457
458
459
460
461
462
463
464
465

The Wetlands Supplement introduces more detailed guidance for organic soils by the introduction of the impactof the drainage class into the methodological approach in the 2006 IPCC Guidelines. It introduces also new
subcategories to some land-use categories, mostly under the land-use category Wetlands. Also the wastewater
treatment category in the Waste Sector is complemented with one additional subcategory (constructed wetlands).
The supplementary methodological guidance for these categories is mainly different by land-use category.
Therefore it suggested to that the inventory compilers consider the land-use categories for which theemissions/removals are estimated using the supplementary methodologies separately in the key category analysis.
The suggested level for the key category analysis for the AFOLU and Waste Sectors is included in Table 7.3.
The changes to the Table 4.1 in Volume 1 of the 2006 IPCC Guidelines are highlighted with shading.

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TABLE 7.3
SUGGESTED AGGREGATION LEVEL OF ANALYSIS FOR APPROACH 1 FOR AFOLU AND WASTE SECTORS a
Source and Sink Categories to be Assessed in Key
Category Analysis
Category Codeb

Category Titleb

Gases to beAssessed cSpecial Considerations

CH4

If this category is key, the inventory
compiler should determine which animal
categories are significant. For key
categories, decision trees for livestock
population characterisation as well as forCH4 emissions estimation should be
followed.

CH4, N2O

If this category is key, the inventory
compiler should determine which animal
categories and waste management systems
are significant. For key categories,
decision trees for livestock population
characterisation as well as for CH4 or N2Oemissions estimation should be followed.

CO2

If this category is key, the inventory
compiler should determine which pools(biomass, DOM, mineral soils, organicsoils) are significant and should thenfollow the guidance for key categories indecision trees for carbon stock changes
for the significant pools. This category
would include rewetted lands classified asforest land remaining forest lande

CO2

If this category is key, the inventory
compiler should determine which poolsand subcategories are significant. This
category would include rewetted lands
classified as land converted to forest lande

CO2

If this category is key, the inventory
compiler should determine which pools
are significant. This category would
include rewetted lands classified as
cropland remaining croplande

CO2

Assess the impact of forest land converted
to cropland in a separate category. d If thiscategory is key, the inventory compiler
should determine which pools andsubcategories are significant. This
category would include rewetted lands
classified as land converted to cropland.e

CO2

If this category is key, the inventory
compiler should determine which pools
are significant. This category would
include rewetted lands classified as
grassland remaining grassland.e

CO2

Assess the impact of forest land converted
to grassland in a separate category. d
If this category is key, the inventory
compiler should determine which poolsand subcategories are significant. This
category would include rewetted lands
classified as land converted to grassland.e

Agriculture, Forestry and Other Land Use

3A1

3A2

3B1a

3B1b

3B2a

3B2b

3B3a

3B3b

7.14

Enteric Fermentation

Manure Management

Forest Land Remaining Forest Land

Land Converted to Forest Land

Cropland Remaining CroplandLand Converted to Cropland

Grassland Remaining Grassland

Land Converted to Grassland

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TABLE 7.3
SUGGESTED AGGREGATION LEVEL OF ANALYSIS FOR APPROACH 1 FOR AFOLU AND WASTE SECTORS a
Source and Sink Categories to be Assessed in Key
Category Analysis
Category Codeb

Category Titleb

Gases to beAssessed cSpecial Considerations

Assess the impact of peat extraction
including the use of horticultural peat
together for lands remaining andconverted to peat extraction. If thiscategory is key, the inventory compiler
should determine which subcategories andpools are significant.

3B4ai + 3B4bi

Peat Extraction lands (Remaining as
and converted to Peat Extraction
lands

CO2, N2O, CH4

3B4aiiFlooded land remaining Flooded
land

CO2

3B4aiii

3B4b

3B5a

3B5b

Wetlands remaining wetlands(excluding 3B4ai and 3B4aii)

Land Converted to Wetlands(excluding 3B4bi)

Settlements Remaining Settlements

Land Converted to Settlements

CO2, N2O, CH4

This category would include rewetted land,
coastal wetlands and inland mineral soil
wetlands remaining in the relevant
categories and not reported under any otherland-use categories. If this category is key,
the inventory compiler should determine
which subcategories and pools are
significant. This category would include
rewetted lands classified as wetlands
remaining wetlands.e

CO2, N2O, CH4

This category would include lands
converted to rewetted lande, coastal
wetlands and inland mineral soil wetlands
and not reported under any other land-use
categories. Assess the impact of forest
land converted to wetland in a separate
category (see below). d If this category is
key, the inventory compiler should
determine which pools and subcategories
are significant. This category would
include rewetted lands classified as land
converted to wetlands.e

CO2

If this category is key, the inventory
compiler should determine which pools
are significant. The areas of constructedwetland should be included under thiscategory. This category would also
include rewetted lands classified as
settlements remaining settlements.e

CO2

Assess the impact of forest land converted
to settlements in a separate category. d If
this category is key, the inventory
compiler should determine which poolsand subcategories are significant. The
areas of land converted to constructedwetland should be included here. This
category would include rewetted lands
classified as land converted tosettlements.e
CO2 emissions should be included only
for those sources which are not covered
under reporting of CO2 emissions/removals in categories 3B1 to 3B6.
If this category is key, the inventory
compiler should determine which
subcategories are significant.

3C1

Biomass Burning

CO2, CH4, N2O

3C2Liming

CO2

3C3

Urea Application

CO2

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TABLE 7.3
SUGGESTED AGGREGATION LEVEL OF ANALYSIS FOR APPROACH 1 FOR AFOLU AND WASTE SECTORS a
Source and Sink Categories to be Assessed in Key
Category Analysis
Category Codeb

Category Titleb

Gases to beAssessed cSpecial Considerations

3C4

Direct N2O Emissions fromManaged soils

N2O

If this category is key, the inventory
compiler should determine which
subcategories are significant.

3C5

Indirect N2O Emissions fromManaged soils

indirect N2O

If this category is key, the inventory
compiler should determine which
subcategories are significant.

3C6

Indirect N2O Emissions fromManure Management

indirect N2O

3C7

Rice Cultivations

CH4

3D1

Harvested Wood Products

CO2

Use of key category analysis is optional.

Miscellaneous

CO2, CH4, N2O

Assess whether other sources or sinks in
the AFOLU Sector not listed above
should be included. Key category analysis
has to cover all emission sources andsinks in the inventory. Therefore allcategories not presented above should beeither aggregated with some othercategory, where relevant, or assessed
separately.

4A

Solid Waste Disposal

CH4

If this category is key, the inventory
compiler should determine which
subcategories are significant.

4B

Biological Treatment of Solid Waste

CH4, N2O

4C

Incineration and Open Burning of
Waste

CO2, N2O, CH4

4D

Wastewater Treatment andDischarge

3

Waste

CH4, N2O

Assess whether domestic or industrial
wastewater treatment is a significant
subcategory. Emissions from constructedwetlands are included in this category.
Assess whether other sources in the Waste
Sector not listed above should be
included. Key category analysis has tocover all emission sources in theinventory. Therefore all categories notpresented above should be either
aggregated with some other category,where relevant, or assessed separately.

4

Miscellaneous

CO2, CH4, N2O

5A

Indirect N2O Emissions from theatmospheric deposition of nitrogenin NOx and NH3

indirect N2O

5B

7.16

Other

CO2, N2O, CH4,
SF6, PFCs, HCFs

Include sources and sinks reported under
5B. Key category assessment has to cover
all emission sources in the inventory.
Therefore all categories not presented
above should be either aggregated withsome other category, where relevant, orassessed separately.

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TABLE 7.3
SUGGESTED AGGREGATION LEVEL OF ANALYSIS FOR APPROACH 1 FOR AFOLU AND WASTE SECTORS a
Source and Sink Categories to be Assessed in Key
Category Analysis
Category Codeb

Category Titleb

Gases to beAssessed cSpecial Considerationsa

In some cases, inventory compilers may modify this list of IPCC categories to reflect particular national circumstances.
The categories should include the respective codes and be consistent with the IPCC terminology.
c
All the gases in this column are to be assessed separately, except ‘Miscellaneous’ category, where gases can be assessed jointly. There
may also be some new gases other than those listed here, and those should also be assessed separately.
d
In the quantitative key category analysis, conversion of forest land is spread out under the different land-use change categories.
Countries should identify and sum up the emission estimates associated with forest conversion to any other land category and compare
the magnitude to the smallest category identified as key. If its size is larger than the smallest category identified as key it should beconsidered key.
e
In the quantitative key category analysis, emissions/removals from rewetting are spread out under the different land-use change
categories. Countries should identify and sum up the emission/removal estimates associated rewetting to any other land category andcompare the magnitude to the smallest category identified as key. If its size is larger than the smallest category identified as key itshould be considered key.
b

466
467

7.5

COMPLETENESS

468
469
470
471
472
473
474

Completeness means that inventory estimates have been prepared for all categories and gases. Complete
greenhouse gas inventories will include estimates of emissions and removals from the sources and sinks forwhich methodological guidance is provided in the 2006 IPCC Guidelines and the Wetlands supplement unlessthe specific sources and sinks do not occur on the national territory. The decision tree in Figure 1.1 in Chapter 1of this report and Table 7.1 above provides guidance on the links between guidance in the 2006 IPCC Guidelines
and the Wetlands Supplement to facilitate countries in ensuring complete coverage of all relevant categories in
the inventory.

475
476
477
478
479
480
481
482
483
484
485
486

A country may consider that a disproportionate amount of effort would be required to collect data for a category
or a gas from a specific category that would be insignificant in terms of the overall level and trend in nationalemissions. The Wetlands Supplement addresses sources and sinks for which the significance varies considerably
by country. For instance, some wetland types occur only in some regions of the world, the amount of organicsoils may be very small in some countries and tidal effects on the emissions are applicable only to coastal
countries. In circumstances where the supplementary guidance is not applicable to a country or
emissions/removals have not been reported due to their insignificance, they should use the notation keys “NO”
(not occurring) and “NE” (not estimated) respectively. For details on the use of the notation keys, the inventory
compilers should refer to together with a justification for exclusion in terms of the likely level of emissions or
removals and identify the category as 'Not Estimated' using the notation key 'NE' in the reporting tables (refer to
Section 8.2.5 in Volume 1 of the 2006 IPCC Guidelines), The inventory compiler should note that it is goodpractise to provide justification for each emission estimate for which the notation key “NE” is used.

487

7.6

TIME SERIES CONSISTENCY

488

7.6.1

Overview of time series issues

489
490
491
492

Greenhouse gas inventory methods should be consistent for an entire time series so that each year in the timeseries can be validly compared with other years. This provides countries with information to robustly assess
temporal trends in their greenhouse gas emissions and removals and the effectiveness of emissions reduction
actions. Circumstances that will affect time series consistency include:493•

changes and refinements to methods due to scientific advances494•

addition of new categories

495•

technological change

496•

data gaps

497•

correction of errors

498
499

In a consistent time series, changes in emissions or removals over time will be due to real phenomena in the fieldrather than any influence of the above set of circumstances in the calculations.

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501
502

This Wetlands Supplement includes substantial changes to the 2006 IPCC Guidelines methods and refines thesubcategories within the wetlands land-use category. For some countries, this will make necessary therecalculation of results from previous years to produce a consistent time series.

503
504
505

This section summarizes material from and adds recent scientific information to sections from the 2006 IPCC
Guidelines, including Volume 1, Chapter 5 (Irving et al. 2006) and Volume 4, Chapter 7. Inventory compilers
should consult the detailed information in the 2006 IPCC Guidelines.

506

7.6.2

507
508
509
510

The guidance for producing consistent times series for the categories in the Wetlands Supplement is addressed
below taking the tier used to estimate the emissions/removals into account as the requirements for activity dataand emission factors as well as other parameters are very different depending on the tier used, and thus impact
the methods by which times series consistency is ensured.

511
512
513
514
515
516

All tiers - Recalculate an entire data series when changing from the 1996 IPCC Guidelines, 2003 Good PracticeGuidance, and 2006 IPCC Guidelines to the Wetlands Supplement, when methods are refined due to scientificadvances, when new data becomes available, when quality control finds errors in previous estimates, and whenwetlands are reported as a new category separate from previously reported land-use categories (e.g. reporting
mangroves as wetlands rather than forests). For data gaps, it is good practice to clearly report which results arecalculated from measurements and which are modelled.

517
518

Tier 1 – Use the activity data for years available in the default sources in the Wetlands Supplement and the 2006
IPCC Guidelines. Report data from years of measurement only.

519
520

Tier 2 - To fill data gaps, examine all available historical sources, administrative records, aerial photographs, or
remote sensing. Use linear interpolation to fill historical data gaps.

521
522
523
524
525
526
527
528
529

Tier 3 –To fill data gaps, interpolate using a function that models empirical trends or underlying processes.
Some examples include field validation of model dead wood time series in the Netherlands national greenhousegas inventory (van der Maas et al. 2011; Figure 7.1), data gap filling of CO2 fluxes from Everglades National
Park, USA (Barr et al. 2010), and filling of night-time gaps in ecosystem respiration in Lake Victoria wetlands,
Uganda (Saunders et al. in press). The case of the Netherlands is just an example that illustrates recalculation ofa time series to improve consistency. When field measurements of dead wood showed that modelled estimates
were not accurate, the inventory agency revised the parameters in its dead wood model and recalculated theentire time series (van der Maas et al. 2011; Figure 7.1). Refer to the 2006 IPCC Guidelines (Irving et al. 2006)
for detailed steps of filling historical gaps by splicing and for the use of surrogate parameters.

530
531
532

Figure 7.1

533
534

Methods for producing consistent time series

Filling data gaps by multivariate statistical analysis and recalculation of thetime series of carbon in dead wood in the Netherlands national greenhousegas inventory.

Note that the graph clearly distinguishes between measured and modelled values (van der Maas et al. 2011).

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7.7

QUALITY ASSURANCE AND QUALITYCONTROL

537

7.7.1

Overview of quality issues

538
539
540
541
542

Quality assurance and quality control are procedures to ensure the accuracy of calculated results. Effectively
implemented quality procedures can reduce uncertainties of greenhouse gas inventories. Quality control (QC) isa system of routine technical activities that inventory compilers undertake to assess and maintain the condition ofdata and results as they compile the inventory. Quality assurance (QA) is a planned system of review of finishedinventory results conducted by personnel not directly involved in the inventory.

543
544
545
546
547
548

This section summarizes material from and adds recent scientific information to sections from the 2006 IPCC
Guidelines, including Volume 1, Chapter 6 (Winiwarter et al. 2006) and Volume 4, Chapter 7. Inventory
compilers should consult the detailed information in the 2006 IPCC Guidelines. The guidance below isorganised taking the tier used to estimate the emissions/removals from the categories included in this Wetlands
Supplement into account to emphasize that specific QA/QC measures will depend on the tier level of themethodology.

549

7.7.2

550
551
552
553
554
555
556
557

All tiers – Provide routine and consistent checks to ensure data integrity, correctness, and completeness. Identify
and address errors and omissions. Document and archive inventory material and record all quality control
activities. Check labelling, transcription, and other clerical related to data entry (See complete list in 2006 IPCC
Guidelines, Volume 1, Table 6.1). Double-check outlying values against data sources. Check final results against
previous years and published values. Compare inventories with results from similar ecosystems in othercountries. Conduct an area-balance for land-use category areas and a mass-balance for greenhouse gas emissions
and removals. Develop automated data control procedures. It is good practice to prioritize key categories formore extensive quality assurance and quality control.

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Tier 1 - Double-check that correct default values were used.

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Tier 2 - Double-check data sheets against local data sources used for activity data, emissions factors, and othervariables.

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Tier 3 - Validate computer models against field measurements and include the error in the calculation of
uncertainty (Section 7.2.1). The validation measure can be correlation of predicted and measured values (Figure
7.2; Miehle et al. 2006), fractional agreement of modelled and measured values (Figure 7.3; Chadwick 2011), or
other measures. Separate the data set used for calibration of a model from the data set used for validation of themodel. It is good practice to establish a system of repeated monitoring of permanent plots or benchmark sites forcontinued validation of model output against field data over time. When more than one model is available for aparticular parameter, inter-comparison of model output can provide indications of the robustness of individualmodel output. Furthermore, comparison of Tier 3 models with estimates using Tier 1 and Tier 2 methods canserve that same purpose. IPCC (2011) provides numerous specific examples of model development, calibration,and validation.

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Figure 7.2

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Validation of the Forest DNDC model by comparison of modelled against
measured values of aboveground biomass in Eucalyptus globulus in Australia(Miehle et al. 2006).

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Figure 7.3

Validation of Ikonos satellite-derived land cover using an error matrix
comparing remote sensing-derived wetlands classes in Florida, USA against
field observations (Chadwick 2011).

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