Chapter 1: Introduction

CHAPTER 1

INTRODUCTION

2013 Supplement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories: Wetlands

1.1Chapter 1: Introduction

Coordinating Lead Autho rs
Tom Wirth (USA) and Chengyi Zhang (China)

Lead Autho rs
Gusti Zakaria Anshari (Indonesia), Kenneth Byrne (Ireland), Elke Hodson (Switzerland/USA), Hans Joosten(EC/WI/FAO), J. Boone Kauffman (IUCN/UNESCO), Leif Klemedtsson (Sweden), Tuija Elina Lapvetelainen†(Finland), Christoph Mueller (Germany), Phillip O'Brien (Ireland) and Mitsuru Osaki (Japan)

Cont ributing Autho rs
Tonya Del Sontro (Switzerland), Mark Flugge (USA), Stephen Ogle (USA), Riitta Pipatti (Finland), Rachel
Steele (USA), Victoria Thompson (USA) and Kiyoto Tanabe (IPCC TFI TSU)

Review Edito rs
Fatih Evrendilek (Turkey) and Steen Gyldenkærne (Denmark)† Ms. Tuija Elina Lapvetelainen, a close colleague, passed away in July 2013. She greatly contributed to the development of
Chapter 1.

1.2

2013 Supplement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories: Wetlands

Chapter 1: Introduction

Contents
1

Introduction ............................................................................................................................................... 4
1.1

Background ....................................................................................................................................... 4

1.2

Guidance for using this supplement .................................................................................................... 4

1.3

Application of the Managed Land Proxy to wetlands .......................................................................... 9

1.4

Coherence and compatibility with 2006 IPCC Guidelines ................................................................. 11

1.4.1

Guidance on activities in the 2006 IPCC Guidelines that are also covered in the Wetlands
Supplement............................................................................................................................... 11

1.4.2

Supplementary guidance in this report ...................................................................................... 12

1.5

Relevant databases for wetlands and organic soils ............................................................................ 16

References................................................................................................................................................ 17

FiguresFigure 1.1

Decision tree for finding the appropriate guidance chapter within the Wetlands
Supplement or the 2006 IPCC Guidelines ....................................................................... 5

Figure 1.2

Soil based subcategories that are being addressed in the Wetlands Supplement ................ 6

Figure 1.3

Typical management practices on organic and wet soils ................................................ 10

TablesTable 1.1

Look-up table for Wetlands Supplement by land-use categories, soil type and condition
and inland or coastal location ........................................................................................ 15

Table 1.2

Global and regional on-line resources providing metadata sets for developing an inventoryof greenhouse gas emissions and removals from wetlands and organic soils................... 16

Box
Box 1.1

Greenhouse gas emissions and removals of managed organic and wet soils ..................... 92013 Supplement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories: Wetlands

1.3Chapter 1: Introduction

1 INTRODUCTION
1.1

BACKGROUND

The 2006 IPCC Guidelines for National Greenhouse Gas Inventories (2006 IPCC Guidelines) acknowledgedthat the methodological guidance for the land-use category Wetlands in Volume 4 (Agriculture, Forestry andOther Land Use—AFOLU), Chapter 7 (Wetlands) is incomplete and limited to estimating emissions of carbon
dioxide (CO2) and nitrous oxide (N2O) from peatlands cleared and drained for production of peat for energy,
horticultural and other uses (Section 7.2, Chapter 7 in Volume 4 of the 2006 IPCC Guidelines), and to CO2emissions from land converted to flooded land such as reservoirs for production of hydroelectricity, irrigationand navigation (Section 7.2, Chapter 7 in Volume 4 of the 2006 IPCC Guidelines). In October 2010, an IPCC
expert meeting on harvested wood products, wetlands, and N2O emissions from soils concluded that there wassufficient new scientific information available to provide additional methodological guidance and fill gaps in theexisting 2006 IPCC Guidelines for the rewetting and restoration of peatlands; emissions from fires, ditches, andwaterborne carbon; and constructed wetlands for waste water disposal (IPCC, 2011). In December 2010, theSubsidiary Body for Scientific and Technological Advice (SBSTA) of the United Nations Framework
Convention on Climate Change (UNFCCC) invited the IPCC to undertake further methodological work on
wetlands, focusing on the rewetting and restoration of peatland, with the objective of filling in the gaps in the2006 IPCC Guidelines in these areas.
In response to the invitation of SBSTA, this 2013 Supplement to the 2006 IPCC Guidelines for National
Greenhouse Gas Inventories: Wetlands - Methodological Guidance on Lands with Wet and Drained Soils, andConstructed Wetlands for Wastewater Treatment - (Wetlands Supplement) provides new and supplementary
guidance on estimating and reporting greenhouse gas emissions and removals from lands with organic soils andwet and drained mineral soils in Wetlands and all the other IPCC land-use categories with these soil types thatare subject to human activities (‘managed’). The Wetlands Supplement is organised into the following chapters:•

Chapter 2: Drained Inland Organic Soils•

Chapter 3: Rewetted Organic Soils•

Chapter 4: Coastal Wetlands•

Chapter 5: Inland Wetland Mineral Soils•

Chapter 6: Constructed Wetlands for Wastewater Treatment•

Chapter 7: Cross-Cutting Issues and Reporting

1.2

GUIDANCE FOR USING THIS SUPPLEMENT

This introductory chapter provides guidance on the way to use the Wetlands Supplement in conjunction with theexisting 2006 IPCC Guidelines, for the preparation of a greenhouse gas inventory that includes lands withorganic soils and wet and drained mineral soils across all the IPCC land-use categories.
Inventory compilers can use the decision tree (Figure 1.1) as a guide to the relevant chapters within this
Wetlands Supplement and/or the 2006 IPCC Guidelines. The numbers located near the ‘start’ box and the
diamonds in the decision tree refer to the guidance notes listed below, which explain and illustrate the terms usedin the decision tree and within this document (see also the glossary).
The terms are for the purpose of this document, and their definitions are not intended to pre-empt otherdefinitions of these terms in any other context. For example, except for the use of the term ‘Wetlands’ in thename of this supplement, this guidance uses the term ‘Wetlands’ (with a capital ‘W’ and always plural) solely torefer to the IPCC land-use category Wetlands. The term ‘wetland’ or ‘wetlands’ (with a lowercase ‘w’ andsingular or plural) is used to refer to land with wet soil as defined in note 4 below. Other articulations of theconcept of ‘wetland’ are possible, for example that used by the Ramsar Convention(www.ramsar.org/cda/en/ramsar-documents-texts-convention-on/main/ramsar/1-31-38%5E20671_4000_0__)
but this does not affect the applicability of the methodological guidance.

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2013 Supplement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories: Wetlands

Chapter 1: Introduction

Figure 1.1

Decision tree for finding the appropriate guidance chapter within the
Wetlands Supplement or the 2006 IPCC Guidelines
Start: Determine
land-use category

Is the soil used
for rice cultivation?

1)
2)

Yes

Vol.4, Chapters 5
and 11,
2006 IPCC
Guidelines
andChapters 2 and 5,
Wetlands
Supplement

Yes

Vol.4, Chapter 7,
2006 IPCC
Guidelines

Yes

Chapter 6,
Wetlands
Supplement

Yes

Chapter 4,
Wetlands
Supplement

Yes

Chapter 5,
Wetlands
Supplement

Yes

Chapter 3,
Wetlands
Supplement5)
Vol.4, 2006 IPCC
Guidelines(To be read in
conjunction with new
guidance available in
Chapters 4 and 5,
Wetlands Supplement)

No

No

Is the soilorganic and/or
wet?

3), 4)Yes
6)
Is this a“Flooded Land”?

No
7)
Is thisa wetland for wastewater
treatment?

No
8)
Is thiscoastalland?
NoIs thisinland mineral
soil?

•

•

The numbers associated with the shapes
in the decision tree refer to the notes
which follow the decision tree.
Except for Chapter 4, the Wetlands
Supplement only deals with greenhousegas fluxes and carbon stock changes insoils. For guidance on other pools,
refer to the 2006 IPCC Guidelines.

9)

No
10)
Is this organic
soil wet?

No
Chapter 2,
Wetlands
Supplement

Note 1: Determine land-use category
The Wetlands Supplement covers land with organic soils, and wet and drained mineral soils (see notes 2, 3, and 4
for the definition of these terms) across all the IPCC land-use categories (Forest Land, Cropland, Grassland,

2013 Supplement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories: Wetlands

1.5Chapter 1: Introduction

Wetlands, Settlements, and Other Land, see Figure 1.2). The Wetlands Supplement is consistent with Chapter 3(Consistent Representation of Lands) in Volume 4 of the 2006 IPCC Guidelines in that it does not change theassignment of land to a category. If using Approach two or three for land representation 1, land-use conversions
should also be identified (e.g. Forest Land converted to Cropland, Cropland converted to Settlements).
In comparison with the 2006 IPCC Guidelines, the Wetlands Supplement identifies relevant subcategories (seeFigure 1.2 below) and specifies emission factors for all land-use categories with organic soils and wet anddrained mineral soils (including drained ‘wetland mineral soils’ (see Note 4 below) subject to rewetting; inland
wetland mineral soils subject to long-term cultivation; inland dry mineral soils that have been wetted; coastal
drained mineral soils subject to rewetting and coastal mineral soils subject to other management practices2). The
Wetlands Supplement differentiates between coastal land and inland land, because water salinity and dynamics(e.g. tides) may, for the same land-use category, modify emission factors compared to inland land. .
Figure 1.2

Soil based subcategories addressed in the Wetlands Supplement

Notes on Figure 1.2: Guidance for all the soils shown in this figure is included the Wetlands Supplement. Guidance for ‘mineral dry’soils except for those drained for long-term cultivation and drained coastal wetlands (see Note 5) is provided in the 2006 IPCC
Guidelines.

It is good practice to subdivide each land use/conversion category into subcategories with similar characteristics.
The Wetlands Supplement proposes to use - in addition to the dry mineral soils covered by the 2006 IPCC
Guidelines - a division into four soil subcategories 3; all with a coastal and inland subdivision where appropriate(see Figure 1.2 above):1)

drained mineral soil

2)

wet mineral soil

3)

wet organic soil

4)drained organic soil.

In the case of dry mineral soil, the guidance in the Forest Land, Cropland or Grassland Chapters in the 2006
IPCC Guidelines should be used as appropriate. Chapter 4 of the Wetlands Supplement provides new guidancefor drained coastal mineral soils, and Chapter 5 presents new guidance for drained inland wetland mineral soils
1

Cf. Section 3.3.1, Chapter 3 in Volume 4 of the 2006 IPCC Guidelines

2

Other management activities on coastal wetland mineral soils covered in the Supplement include extraction, revegetation
and aquaculture.

3

The guidance for rice cultivation provided in Chapters 2 and 5 of the Wetlands Supplement should be used in conjunction
with Chapters 5 and 11 in Volume 4 of the 2006 IPCC Guidelines.

1.6

2013 Supplement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories: Wetlands

Chapter 1: Introduction(see Note 4 below) that have been continuously managed for > 20 years to cultivate predominantly annual crops.
In all other cases, the decision tree should be used (see Figure 1.1 above) to identify the appropriate guidance
chapter within this Wetlands Supplement or within the 2006 IPCC Guidelines
The 2006 IPCC Guidelines are used for estimating and reporting anthropogenic greenhouse gas emissions andremovals only. With respect to ‘land’ inventory compilers are required to differentiate between ‘managed’ and‘unmanaged’ land for all land-use categories besides Cropland and Settlements, which are inherently managed
land. The Wetlands Supplement continues to apply the Managed Land Proxy (see Section 1.3 of this supplement)
to estimate anthropogenic greenhouse gases. In the case of coastal wetlands, guidance is provided to estimate
and report anthropogenic emissions and removals from specific management activities.
Note 2: Is the soil used for rice cultivation?
Guidance on rice cultivation is provided in Chapters 2 and 5 of the Wetlands Supplement, and Chapters 5 and 11
in Volume 4 of the 2006 IPCC Guidelines.
Note 3: Is the soil organic?
An organic soil is a soil with a high concentration of organic matter (see below). Every soil that is not an organic
soil is classified as a mineral soil, following the 2006 IPCC Guidelines (Annex 3A.5, Chapter 3 in Volume 4).
The Wetlands Supplement follows the definition of organic soils in the 2006 IPCC Guidelines (Annex 3A.5,
Chapter 3 in Volume 4):
Organic soils are identified on the basis of criteria 1 and 2, or 1 and 3 listed below (FAO 1998):
1. Thickness of organic horizon greater than or equal to 10 cm. A horizon of less than 20 cm must have 12
percent or more organic carbon when mixed to a depth of 20 cm.
2. Soils that are never saturated with water for more than a few days must contain more than 20 percent organiccarbon by weight (i.e., about 35 percent organic matter).
3. Soils are subject to water saturation episodes and has either:a. At least 12 percent organic carbon by weight (i.e., about 20 percent organic matter) if the soil has no clay;orb. At least 18 percent organic carbon by weight (i.e., about 30 percent organic matter) if the soil has 60% ormore clay; orc. An intermediate proportional amount of organic carbon for intermediate amounts of clay.
The 2006 IPCC Guidelines largely follow the definition of Histosols by the Food and Agriculture Organization(FAO), but have omitted the thickness criterion from the FAO definition to allow for often historicallydetermined, country-specific definitions of organic soils.
There are no IPCC definitions for peat and peatland. Definitions of peatland and peat soil differ between
countries in relation to the thickness of the peat layer required to be determined as a peatland or a peat soil. In
addition, the definition of peat varies among countries and disciplines, especially with respect to the minimum
percentage of organic matter the material is required to contain (Joosten and Clarke, 2002). In the Wetlands
Supplement the concept of peatland is considered to be included in ‘(land with) organic soil’.
It is good practice that, when a country uses another definition of organic soil in accordance with its national
circumstances, the concept of organic soil (and its possible subdivisions) applied is clearly defined, and that thedefinition is applied consistently both across the entire national land area and over time.
Note 4: Is the soil wet?
A wet soil is a soil that is inundated or saturated by water for all or part of the year to the extent that biota,
adapted to anaerobic conditions, particularly soil microbes and rooted plants, control the quality and quantity of
the net annual greenhouse gas emissions and removals. Every soil that is not a wet soil is in this supplementclassified as a dry soil.
Drainage is the process of artificial lowering of the soil water table. In this supplement, the term is used todescribe the act of changing a soil from wet into dry. A drained soil is a soil that has formerly been a wet soil,
but as a result of human intervention has become a dry soil. All organic soils are assumed to have originally been
wet, therefore a dry organic soil is always also a drained organic soil.
Rewetting is the process of changing a drained soil into a wet soil. A rewetted soil is a soil that has formerly
been a drained soil but as a result of human intervention has become a wet soil. Similarly, wetting is the processof changing an originally dry soil into a wet soil as a result of human intervention, as in wetland creation.
Restoration (adjective restored) is the process of assisting the recovery of an ecosystem that has been degraded,
damaged, or destroyed. In the case of drained former wetlands, restoration always has to include rewetting.
With respect to inland wet mineral soils the Wetlands Supplement only provides Tier 1 guidance for ‘wetland
mineral soils’ and mineral soils that have been wetted by human intervention for the purpose of wetland creation.

2013 Supplement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories: Wetlands

1.7Chapter 1: Introduction‘Wetland mineral soils’ include the ‘wetland soils’ as defined in footnote 6 to Table 2.3, Chapter 2 in Volume 4of the 2006 IPCC Guidelines as Soils with restricted drainage leading to periodic flooding and anaerobic
conditions (in WRB classification Gleysols; in USDA classification Aquic suborders). Sandy soils (as defined byfootnote 3 to Table 2.3, Chapter 2 in Volume 4 of the 2006 IPCC Guidelines) that are wet are not included.
Chapter 3 of the Wetlands Supplement covers organic soils that are rewetted and wet organic soils that are
subject to other management practices such as paludicultures. Chapter 4 covers coastal wetland soils that are
subject to rewetting (after drainage) and to other management practices such as extraction, revegetation andaquaculture. Chapter 5 covers rewetting of drained inland wetland mineral soils and wetting of originally dry
mineral soils.
Note 5: New guidance for drained coastal mineral soils and ‘inland wetland mineral soils’
Dry mineral soils in inland lands that are subject to management activities other than rewetting or wetting
respectively are covered in Volume 4, 2006 IPCC Guidelines. Chapter 4 of the Wetlands Supplement provides
new guidance for drained coastal mineral soils, and Chapter 5 presents new guidance on ‘inland wetland mineralsoils’ (see Note 4 above) that have been continuously cultivated (by default for > 20 years) with predominantly
annual crops. Tier 1 methods for both mineral and organic soils do not differentiate between recently and longtime drained soils.’
Drained mineral soils may have a high organic matter content that gives them different greenhouse gas emission
characteristics from those of mineral soils that have never been wet, or which were originally wet, but have been
in a dry state for a long time. These differences fade with time after drainage, but so long as they persist, the soil
is described in this supplement as being ‘drained’.
Note 6: Is this a ‘Flooded Land’?
Flooded Land is defined in the 2006 IPCC Guidelines as water bodies where human activities have causedchanges in the amount of surface area covered by water, typically through water level regulation. Examples ofFlooded Land include reservoirs for the production of hydroelectricity, irrigation, and navigation. Regulated
lakes and rivers that do not have substantial changes in water area in comparison with the pre-flooded
ecosystem are not considered as Flooded Lands. Some rice paddies are cultivated through flooding of land, but
because of the unique characteristics of rice cultivation, rice paddies are addressed in Chapter 5 (Cropland) of
the Guidelines (Section 7.3, Chapter 7 in Volume 4 of the 2006 IPCC Guidelines).
This Wetlands Supplement does not include additional guidance for Flooded Land. Estimating emissions fromthis category of land use is discussed in Section 7.3, Chapter 7 of Volume 4 of the 2006 IPCC Guidelines.
Reservoirs constructed as wetlands for wastewater treatment are covered in Chapter 6 of the Wetlands
Supplement.
Note 7: Is this a wetland for wastewater treatment?
A wetland for wastewater treatment is a wetland that is used for or influenced by waste water treatment. Chapter
6 of the Wetlands Supplement provides guidance for wetlands for wastewater treatment, both for wetlands thatare constructed for such a purpose (constructed wetlands for wastewater treatment) and for natural wetlands thatare used for, or influenced by, wastewater treatment. The emissions are reported under the Waste Sector. Other
constructed (i.e. man-made, engineered or artificially created) wetlands are included in Chapter 5 of the
Wetlands Supplement.
Note 8: Is this coastal land?
Coastal land is land at or near the coast. It is good practice for a country to clearly define the concept of ‘coastal
land’ and its sea- and landward limits in accordance with its national circumstances, and to apply that definition
consistently across the entire national land area and over time. All land that is not coastal is inland.
A coastal wetland is a wetland (see Note 4) at or near the coast that is influenced by brackish/saline water and/or
astronomical tides. Coastal wetland may occur on both organic and mineral soils. Brackish/saline water is waterthat normally contains more than 0.5 or more parts per thousand (ppt) of dissolved salts. Every mineral soil
wetland that is neither a coastal wetland, a Flooded Land (see Note 6) nor a constructed wetland for waste water
treatment (see Note 7) is classified as inland wetland (cf. Chapter 5).
Note 9: Is this inland mineral soil?
Inland mineral soil is all mineral soil (see Note 3) that is not on coastal land (see Note 8).
Note 10: Is this organic soil wet?
Chapter 3 of the Wetlands Supplement focuses on rewetted organic soils and peatlands. While Chapter 3 of the
Wetlands Supplement does not provide Tier 1 methods for management practices such as paludicultures, these

1.8

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Chapter 1: Introduction

are discussed in the general discussion and in the higher tier sections of that chapter. Chapter 2 of the Wetlands
Supplement covers drained organic soils.

BOX 1.1
GREENHOUSE GAS EMISSIONS AND REMOVALS OF MANAGED ORGANIC AND WET SOILS

Lands with organic and wet soils are crucial in maintaining the Earth’s carbon balance as they
contain soils with high organic carbon content (Mitra et al., 2005; Joosten and Couwenberg, 2008;
Donato et al., 2011). Human activities on wetlands (e.g. drainage, agriculture, forestry, peat
extraction, aquaculture) and their effects (e.g. oxidation of soil organic matter) may significantly
affect the carbon and nitrogen balance and, thus, the greenhouse gas emissions and removals fromthese lands. The actual magnitude of human-induced emissions and removals from lands withorganic and wet soils depends on numerous variables, including soil type, type of land
use/conversion, wetland type, wetland size, management practice, vegetation composition, watertable depth, growing season length, salinity, precipitation, and temperature and is discussed ingreater detail within this Wetlands Supplement.
Draining inland organic soils lowers the water table and increases the oxygen content of the soil,
thus increasing CO2 emissions. Methane (CH4) emissions from drained inland organic soils are
generally negligible because the soil carbon is then preferentially oxidized to CO2. However,methanogenesis may take place in drainage ditches with a higher water table causing significant
emissions of CH4 to the atmosphere. Drained organic soils can also emit significant amounts ofN2O from nitrogen in the organic matter or nitrogen added by fertilization. Losses of particulate
and dissolved organic carbon in drainage waters from organic soil are also included in this
Wetlands Supplement (Chapter 2). Rewetting inland organic soils raises the water table again,
decreases CO2 emissions, rapidly decreases N2O emissions to almost zero, and increases CH4emissions compared to the drained state, as the oxygen level in the soil drops and methanogenesis
starts again. Rewetting can also restore wetlands to a state where net CO2 emissions are greatly
reduced or even become negative, causing the wetlands to function as a net remover of greenhousegases from the atmosphere (Chapter 3 of this supplement). CO2 emissions from coastal wetlands
can be significant, especially during the construction phase of aquaculture and salt
production/extraction. CH4 and N2O emissions from coastal wetlands are not significant except
when the wetlands are enriched with nutrients from agricultural run-off or sewage (Chapter 4 ofthis supplement). Restoring and creating wetlands on mineral soils, similar to rewetting organicsoils, creates anoxic conditions and increases CH4 emissions (Chapter 5 of this supplement).
Constructed and semi-natural wetlands used for wastewater treatment emit CH4 and N2O (Chapter
6 of this supplement).

1.3

APPLICATION OF THE MANAGED LANDPROXY TO WETLANDSThe Managed Land Proxy is used in the 2006 IPCC Guidelines and Good Practice Guidance for Land Use,
Land-Use Change and Forestry (GPG-LULUCF) as a pragmatic way to estimate anthropogenic emissions andremovals because detailed factoring out of natural emissions or removals is impractical at the country level.
According to the 2006 IPCC Guidelines (Section 3.2, Chapter 3 in Volume 4), managed land is land where
human interventions and practices have been applied to perform production, ecological or social functions, andall emissions and removals from managed land are to be reported regardless of whether they are anthropogenic
or non-anthropogenic.
The Managed Land Proxy continues to be applied in the Wetlands Supplement. For coastal wetlands (Chapter 4of this supplement), this Wetlands Supplement provides guidance to estimate and report countries’ emissions andremovals from specific management activities such as aquaculture, salt production, and dredging. See Figure 1.3
below for some typical management practices on wetlands.

2013 Supplement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories: Wetlands

1.9Chapter 1: Introduction

Figure 1.3

Typical management practices on organic and wet soils(Figure by Riikka Turunen, Statistics Finland)

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Chapter 1: Introduction

1.4

COHERENCE AND COMPATIBILITY WITH
2006 IPCC GUIDELINESThis section provides an overview of the links between the 2006 IPCC Guidelines and the information presented
in this Wetlands Supplement. Section 1.4.1 presents an outline of the activities in the 2006 IPCC Guidelines thatare topics of additional guidance in this supplement. Section 1.4.2, highlights guidance in this supplement thatwas not previously included in the 2006 IPCC Guidelines, and which may need to be considered by inventory
compilers.

1.4.1

Guidance on activities in the 2006 IPCC Guidelinesthat are also covered in the Wetlands Supplement

CARBON STOCK CHANGES AND CO 2 EMISSIONS AND REMOVALS IN
MINERAL AND ORGANIC SOILSThe 2006 IPCC Guidelines provide guidance for estimating carbon stock changes in mineral soils and drainedorganic soils within the land-use categories Forest Land, Cropland, Grassland, Wetlands, Settlements and Other
Land. In Section 2.3.3, Chapter 2 in Volume 4 of the 2006 IPCC Guidelines, complete guidance is provided at
the Tier 1 level, with additional guidance for Tiers 2 and 3. For mineral soils, the default method is based onchanges in soil carbon stocks over a finite period of time. The change is computed based on the carbon stock
after the management change relative to the carbon stock in a reference condition. To estimate CO2 emissions
from drained organic soils an area-based annual emission factor differentiated by climate region and land use isapplied. The Wetlands Supplement provides additional guidance for both organic and mineral soils (subdivided
into wet and drained) and the information with respect to organic soils is expanded to include activities on wet(undrained, rewetted) organic soils. The information in Table 4.6 in Chapter 4 (Forest Land), Table 5.6 in
Chapter 5 (Cropland), and Table 6.3 in Chapter 6 (Grassland) in Volume 4 of the 2006 IPCC Guidelines, which
provides CO2 emission factors for drained organic soils, is updated in Table 2.1 in the Wetlands Supplement.

CH 4 EMISSIONS FROM MAN AGED SOILS
Section 2.3.3.1, Chapter 2 in Volume 4 of the 2006 IPCC Guidelines assumes that CH4 emissions due to thedrainage of organic soils are negligible. The Wetlands Supplement provides guidance on estimating CH4emissions from drained organic soils and drainage ditches, including default emission factors in Tables 2.3 and2.4 in Chapter 2, respectively.
The 2006 IPCC Guidelines do not provide guidance on estimating CH4 emissions from mineral soils except forin relation to rice cultivation. The Wetlands Supplement provides guidance on this potential source in Table 5.4
in Chapter 5, based upon a review of the available scientific literature.

BIOMASS AND DEAD ORGANIC MATTER CARBON STOCK CHANGESGeneric methodologies for estimating above-ground and below-ground biomass carbon stock changes for allland-use categories are available in Section 2.3.1, Chapter 2 in Volume 4 of the 2006 IPCC Guidelines.
Guidance to estimate the dead organic matter pool is provided in Section 2.3.2, Chapter 2 in Volume 4 of the2006 IPCC Guidelines. More specific guidance by land-use categories can be found in Volume 4 of the 2006
IPCC Guidelines under the specific land-use category Chapters: 4 (Forest Land), 5 (Cropland), 6 (Grassland), 7(Wetlands), 8 (Settlements), and 9 (Other Land). The Wetlands Supplement provides additional guidance forthese carbon pools with respect to coastal wetlands in Section 4.2, Chapter 4.
The Wetlands Supplement does not provide additional guidance for these pools in Chapters 2, 3 and 5.

DIRECT AND INDIRECT N 2 O EMISSIONS FROM MAN AGED SOILS
Methodologies are provided in Section 11.2, Chapter 11 in Volume 4 of the 2006 IPCC Guidelines, for theestimation of both direct and indirect N2O emissions from managed soils. Generic equations are presented for
application to all land areas in aggregate or to specific land-use categories if the activity data are available. N2Oemissions from drained organic soils are estimated using an area-based annual emission factor differentiated byclimate region. The 2006 IPCC Guidelines caution the risk of double counting indirect N2O emissions that arereported elsewhere, e.g. under Agriculture (Chapter 11, Volume 4). This caution is reiterated here in relation to
the use of the additional information about N2O emissions.
Certain Tier 1 N2O emission factors provided in Tables 11.1 (direct emissions), Chapter 11 in Volume 4 of the2006 IPCC Guidelines are updated in Table 2.5, Chapter 2 in the Wetlands Supplement.

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1.11

Chapter 1: Introduction

NON-CO 2 EMISSIONS FROM BIOMASS BURNING
Generic guidance for non-CO2 emissions from the burning of live and dead biomass on managed lands (Forest
Land, Cropland, Grassland, Wetlands, Settlements and Other Land) is provided under Section 2.4, Chapter 2,
Volume 4 of the 2006 IPCC Guidelines. The existing guidance does not include the burning of peat and otherorganic soils, which is a large emission source for some countries. The Wetlands Supplement addresses CO2,CH4 and carbon monoxide (CO) emissions associated with the burning of organic soils.

RICE CULTIVATION
CH4 emissions from rice cultivation are included in Section 5.5, Chapter 5 in Volume 4 of the 2006 IPCC
Guidelines. Soil carbon stock changes are accounted for using guidance as described above in Section 2.3.3,
Chapter 2 in Volume 4 of the 2006 IPCC Guidelines. Chapter 2 of the Wetlands Supplement provides emission
factors for CO2, CH4 and N2O for rice cultivation on tropical drained organic soils.

WETLANDS
Methodologies are provided in the Wetlands chapter of the 2006 IPCC Guidelines (Chapter 7 in Volume 4) toestimate greenhouse gas emissions and removals from peatlands cleared and drained for extracting peat forenergy, horticulture and other uses (Section 7.2, Chapter 7 in Volume 4 of the 2006 IPCC Guidelines).
Emissions from the use of horticultural peat are accounted for in Chapter 7 in Volume 4 of the 2006 IPCC
Guidelines, while emissions from peat used for energy generation are estimated under the Energy Sector(Volume 2 of the 2006 IPCC Guidelines). In the 2006 IPCC Guidelines, guidance for peat extraction that does
not include drainage is not provided; this remains the case in the Wetlands Supplement. CO2 emissions from land
converted to flooded land such as reservoirs for production of hydroelectricity, irrigation and navigation areprovided in Section 7.2, Chapter 7 in Volume 4 of the 2006 IPCC Guidelines; no further guidance is provided
for flooded lands in the Wetlands Supplement.

WASTEWATER TREATMENT
Chapter 6 in Volume 5 of the 2006 IPCC Guidelines (wastewater treatment and discharge) provides amethodology to estimate CH4 and N2O emissions from domestic and industrial wastewater treatment. CO2
emissions from wastewater are not considered in the IPCC Guidelines and should not be included in the national
total emissions because of their biogenic origin. The Wetlands Supplement provides guidance on CH4 and N2Oemissions associated with constructed and natural wetlands used for wastewater treatment.

1.4.2

Supplementary guidance in this report

Figure 1.3 shows schematic representations of typical generic management practices covered in each of thechapters of the Wetlands Supplement. The illustrations are not intended to be comprehensive; rather they are avisual guide to the landscapes and ecosystem types to be considered when using this supplement.

CHAPTER 2—DR AINED INLAND ORGAN IC SOILS
Chapter 2 in the Wetlands Supplement provides an updated summary of emission factors and supplementary
guidance to Volume 4 of the 2006 IPCC Guidelines for use in the estimation of greenhouse gas emissions andremovals from drained inland organic soils in all land-use categories: Forest Land, Cropland, Grassland,
Wetlands, Settlements and Other Land, (see Figure 1.3, Frame B in this chapter).
Additional Tier 1 guidance is provided to include the impact of drainage depth (water-table level) on emissionsof CO2, CH4 and N2O. New emission factors to estimate the release of CH4 from drainage ditches are also
provided.
Chapter 2 in the Wetlands Supplement also identifies additional pathways by which carbon is lost from the soil,
namely: carbon loss as Dissolved Organic Carbon (DOC), as Particulate Organic Carbon (POC), and as
Dissolved Inorganic Carbon (DIC). Guidance is provided to estimate these carbon losses separately from thedirect emissions. The loss of carbon from managed organic soils via DOC can be estimated using the Tier 1
methodology and the emission factors provided. Chapter 2 does not, however, provide Tier 1 methodologies foremissions associated with POC or DIC. However, Annex 2A.1, Chapter 2 in the Wetlands Supplement sets out
the basis for the future methodological development for estimating CO2 emissions associated with waterborne
carbon loss from POC. Fire on drained organic soils causes not only on-site CO2, CH4, and N2O emissions
directly from burning, but also has a high potential to increase off-site carbon loss from waterborne organic
matter. Chapter 2 in the Wetlands Supplement provides supplementary methodological guidance to estimate CO2,CH4 and CO emissions from fires on drained organic soils.

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Chapter 1: Introduction

CHAPTER 3—REWETTED ORGANIC SOILS
Chapter 3 in the Wetlands Supplement provides new guidance and emission factors for organic soils that havebeen drained for forestry, crop production, grazing, peat extraction or other purposes, and have subsequently
been rewetted to re-establish water saturation (see Figure 1.3, Frame C in this chapter). Rewetting may haveseveral objectives such as emission reduction, restoration for nature conservation or enabling other management
practices on saturated organic soils (paludicultures). While restoration may take place on undrained sites (e.g. therestoration of damaged vegetation cover), in the majority of cases restoration will include rewetting.
Chapter 3 provides Tier 1 guidance for assessing greenhouse gas (CO2, CH4 and N2O) emissions and removals
from rewetted organic soils by climate region and general guidance for utilizing higher tier methodologies.

CHAPTER 4—COASTAL WETLANDS
Chapter 4 in the Wetlands Supplement provides guidance on estimating emissions and removals of greenhousegases (CO2, CH4 and N2O) associated with specific activities on managed coastal wetlands that may or may not
result in a land use change. Coastal wetlands are wetlands near the coast that are influenced by tidal and/or salineor brackish water. They may consist of mangrove, tidal marsh and seagrass vegetation and can have organic andmineral soils (see Figure 1.3, Frame A in this chapter). Management practices included in the guidance areaquaculture, salt production, extraction, drainage, rewetting, revegetation and creation, and forest management
practice in mangroves.

CHAPTER 5—INLAN D WETLAND MINERAL SOILS
Chapter 5 in the Wetlands Supplement provides guidance for managed inland wetland mineral soils, including
drained soils subject to rewetting and those under long term cultivation; and any other mineral soils that havebeen wetted by human intervention (e.g. inundation for the purpose of wetland creation) not included in Chapter
4 (coastal wetlands) or Chapter 6 (constructed wetlands for wastewater treatment) in the Wetlands Supplement(see Figure 1.3, Frame E in this chapter). The chapter provides methodologies for estimating greenhouse gas
emissions and removals, delivers updated default reference values for soil organic carbon stocks and offers adefault stock change factor for land-use for long term cultivation of croplands on inland wetland mineral soils. It
also gives guidance that is not contained in the 2006 IPCC Guidelines, including a default stock change factor
for land use for rewetted croplands, and methodologies and emission factors for CH4 emissions for mineral soils
in any land-use category that have been rewetted or inundated for the purpose of wetland creation.
Chapter 5 in the Wetlands Supplement does not provide guidance on the application of the methodology given in
Chapter 11 in Volume 4 of the 2006 IPCC Guidelines, for estimating N2O emissions associated with loss of soil
carbon as a result of changes in land use and/or management on inland wetland mineral soils based on estimatesof the loss of soil carbon in relation to updated and new defaults for SOCREF and SOC stock change factors.
However the chapter suggests a future development on the issue.

CHAPTER 6—CONSTRUCTED WETLANDS FOR WASTEWATERTREATMENT
Chapter 6 in the Wetlands Supplement provides guidance on estimating CH4 and N2O emissions fromconstructed wetlands and semi-natural treatment wetlands used for wastewater treatment (see Figure 1.3, Frame
D in this chapter). The guidance supplements Chapter 6 in Volume 5 of the 2006 IPCC Guidelines in relation towastewater treatment. Default emission factors for different types of constructed wetlands (e.g. those withsurface, subsurface vertical or subsurface horizontal flows) are provided for the Tier 1 method. The types ofwastewater include domestic, industrial wastewater, collected runoff from agricultural land and leachate fromlandfill. To avoid double-counting, N2O emissions from wetlands managed for the filtration of non-point source
agricultural effluents, such as fertilizers, are included in indirect N2O emissions from managed soils (Chapter 11
in Volume 4 of the 2006 IPCC Guidelines) as part of the leaching/runoff and volatilization components ofindirect emissions, and are not considered within this supplement. No specific guidance for estimating potentialchanges in carbon pools associated with constructed wetlands for wastewater treatment is presented in Chapter 6in the Wetlands Supplement. Inventory compilers are encouraged to consider the guidance given in the 2006
IPCC Guidelines and in the Wetlands Supplement for possible approaches to reporting these carbon pools.

CHAPTER 7—CROSS-CUTTING ISSUES AND RE PORTING
Chapter 7 in the Wetlands Supplement provides guidance on reporting and cross-cutting issues, including
uncertainties, key category analysis, completeness, time series consistency, quality control, and quality assurance.
The chapter summarises the good practice guidance on these cross-cutting issues found in Volume 1 of the 2006
IPCC Guidelines and addresses the cross-cutting issues specific to Chapters 2 to 6 of this Wetlands Supplement.
Worksheets that can be used for estimating emissions and removals for each category using the Tier 1 guidance,and revised background tables, are included in the annex of the chapter.

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Chapter 1: Introduction

OVERVIEW OF GENERAL CONSIDERATIONS IN USING THE WETLANDSSUPPLEMENT AND THE 2006 IPCC GUIDELINES
It is good practice for countries to avoid double-counting emissions that have already been estimated elsewherein the greenhouse gas inventory. This is especially relevant because lands with organic soils or with wet soils canbe included under various land categories.
In particular, there is a risk that using the guidance provided in Chapters 4 and 6 of the Wetlands Supplement
could result in double-accounting of N2O emissions from wetlands that result from non-point source agricultural
effluents already addressed as indirect emissions from soil amendments (e.g. nitrogen fertilizers) within Chapter
11 in Volume 4 of the 2006 IPCC Guidelines. Double-counting can be avoided by considering only thosemanagement practices that result in direct N2O emissions.
Chapter 2 of this supplement provides guidance on waterborne carbon (DOC, DIC and PIC). However, if thecountry uses a methodology in which soil carbon stock changes are measured in situ (e.g. soil sampling
associated with forest inventories), it is possible that the waterborne carbon has already been included in acountry’s emission estimates.
Table 1.1 below provides guidance for inventory compilers on which chapters of this Wetlands Supplement are
relevant when considering methods for particular combinations of land use, soil type and soil condition. Where
no guidance is provided in this Wetlands Supplement, the table is blank. To estimate total greenhouse gas
emissions from organic and wet soils correctly, this Wetlands Supplement should be used together with the 2006
IPCC Guidelines.

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2013 Supplement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories: Wetlands

Chapter 1: Introduction

TABLE 1.1
LOOK -UP TABLE FOR WETLANDS SUPPLEMENT BY LAND-USE CATEGORIES, SOIL TYPE AND CONDITION AND INLAND OR COASTAL LOCATION
Forest land
Soil Type

Cropland

Grassland

Wetlands

Settlements

Other Land

Gas
InlandCoastalInlandCoastalInlandCoastalInlandCoastalInlandCoastalInlandCoastalCO2
Mineral Dry

Refer to the 2006 IPCC Guidelines

CH4
N2 O

MineralMineral Drained

CO2

5

4

5

4

5

4

5

4

5

4

5

4

CH4

5

4

5

4

5

4

5

4

5

4

5

4

4

N2 O

Mineral Wet

Organic Wet
Organic
Organic Drained

4

4

4

4

4

4

4

CO2

5

4

5

4

5

4

5

4

5

4

5

4

CH4

5

4

5

4

5

4

5

4

5

4

5

4

N2 O

5

4

5

4

5

4

5

4

5

4

5

4

CO2

3

4

3

4

3

4

3

4

3

4

3

4

CH4

3

4

3

4

3

4

3

4

3

4

3

4

N2 O

3

4

3

4

3

4

3

4

3

4

3

4

CO2

2

4

2

4

2

4

2

4

2

4

2

4

CH4

2

2

2

2

2

2

N2 O

2

2

2

2

2

2

Constructed and Natural Wetlands for
Wastewater treatment

The emission sources discussed in the Wetlands Supplement Chapter 6 provide guidance for the Waste Sector and do not impact on
estimates of emissions and removals within AFOLU. However, the area of constructed wetlands should be reported as Wetlands,
Settlements, or other land-use categories as appropriate, and the impact on biomass, soil carbon and other pools may be considered.
Care is required to avoid double-counting of emissions.

Emissions due to burning of organic soils

Chapter 2 in the Wetlands Supplement provides guidance for estimation of greenhouse gas emissions due to burning of organic soils.
This guidance can be applied across all land use categories as appropriate where burning is reported as occurring.

DOC, DIC, PIC, POC

Chapter 2 in the Wetlands Supplement provides a discussion and guidance on carbon loss from organic soils through water pathways.
This information is relevant to all land-use categories.

Here ‘Mineral Drained’ refers to drained inland wetland mineral soils that are subject to rewetting and drained coastal wetland mineral soils.

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Chapter 1: Introduction

1.5

RELEVANT DATABASES FOR WETLANDSAND ORGANIC SOILS

To generate estimates of emissions and removals from wetlands and organic soils, inventory compilers will needto gather activity data and secondary data, such as soil type (organic or mineral), climate zone, wetland type, size,
water table level, vegetation composition, and management practices. Guidance on data collection is provided in
Chapter 2 in Volume 1 of the 2006 IPCC Guidelines. It is good practice to focus these efforts on collecting dataneeded to improve estimates of key categories, which will vary by country depending on which emission sources
are the largest, have the largest potential to change or have the greatest uncertainty. Chapters 2-6 of the Wetlands
Supplement provide specific guidance on assembling the necessary activity data for implementation of the Tier 1
methodology as well as general guidance on activity data that may be necessary for implementation of higher
tiers. Chapter 7 in the Wetlands Supplement provides general guidance for producing consistent times series
when activity data are not available for all years.
Inventory compilers may be able to collect activity data from in-country natural resource agencies or fromnational experts. To supplement in-country data, or if in-country data are not readily available, inventory
compilers may use internationally available data. Table 1.2 below presents a list of online resources that may
prove useful to inventory compilers in obtaining activity data for estimating greenhouse gas emissions andremovals from the wetlands and organic soils included in this Wetlands Supplement. The most notable wetlands
dataset is the Ramsar database of the Ramsar Convention. For most ‘wetlands of international importance,’ theRamsar database provides relevant characteristics, including: wetland type, area, elevation, persistence of water,
salinity, soil type, land use inside and adjacent to the wetland, and vegetation types. In addition, the FAO
provides a variety of metadata sets, including forestry, agriculture, and carbon emissions on a country scale. The
United Nations Environment Programme (UNEP), in collaboration with the World Conservation Monitoring
Centre (WCMC), has a collection of wetland atlases and offers open source geospatial data. Wetlands
International is the only global non-governmental organisation (NGO) that focuses on wetland best practices,
restoration and conservation. It has regional offices in all continents and has compiled a variety of data on
wetlands and organic soils.
TABLE 1.2
GLOBAL AND REGIONAL ON-LINE RESOURCES PROVIDING METADATA SETS FOR DEVELOPING AN INVENTORY OF
GREENHOUSE GAS EMISSIONS AND REMOVALS FROM WETLANDS AND ORGANIC SOILS

Online Resources
The Ramsar Convention on Wetlands
http://www.ramsar.org

FAOSTAT
http://faostat3.fao.org/home/index.html

United Nations Environment Programme and Word
Conservation Monitoring Centre (UNEP-WCMC)
http://www.unep-wcmc.org/datasets-tools-reports_15.html
GeoNetwork Open Source
Geographic data sharing for everyone
http://geonetwork.grid.unep.ch/geonetwork/srv/en/
main.home
Wetlands International
http://www.wetlands.org/

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Description
The Convention on Wetlands of International Importance (theRamsar Convention) is an intergovernmental treaty that provides theframework for national action and international cooperation for theconservation and wise use of wetlands and their resources.
In 2013, this convention consisted of 167 Contracting Parties, 2,122
wetlands of International Importance, and 205,366,160 hectares of
wetlands designated as Ramsar sites.
A large time series and cross section of data relating to hunger,
commodity prices, foods, forestry, agriculture, and emissions for 245
countries and territories and 35 regional areas, from 1961 to the mostrecent year
This site provides a set of metadata related to conservation in
general. It also contains several atlases of wetlands, e.g. the World
Mangrove Atlas and the World Atlas of Seagrass.
This site is managed by UNEP. It contains geographic metadata thatcan be freely requested.

Wetlands International is the only global not-for-profit organisation
dedicated to the conservation and restoration of wetlands. This NGO
also has several regional metadatasets, e.g. South Asia Wetlands,
Australia Wetlands, etc.

2013 Supplement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories: Wetlands

Chapter 1: Introduction

References
Donato, D.C., Kauffman, J.B., Murdiyarso, D., Kurnianto, S., Stidham, M. & Kanninen, M. (2011) Mangroves
among the most carbon-rich forests in the tropics. Nature Geosciences 4: 293-297.
http://mangroveactionproject.org/files/resources/Donato.etal_2011_NatureGeo_MangroveCarbonStorage.pdf
IPCC (2006) 2006 IPCC Guidelines for National Greenhouse Gas Inventories, Prepared by the National
Greenhouse Gas Inventories Programme, Eggleston H.S., Buendia L., Miwa K., Ngara T. and Tanabe K.
(eds). Published: IGES, Japan.
IPCC (2011) IPCC Expert Meeting on HWP, Wetlands and Soil N2O. Geneva, Switzerland: eds: Eggleston, H.S.,
Srivastava, N., Tanabe, K, Baasansuren, J. and Fukuda, M. IGES, Japan 2011.
Joosten, H. & Clarke, D. (2002) Wise use of mires and peatlands – Background and principles including aframework for decision-making. International Mire Conservation Group / International Peat Society, 304 p.
http://www.peatsociety.org/sites/default/files/files/WUMP_Wise_Use_of_Mires_and_Peatlands_book.pdf
Joosten, H. & Couwenberg, J. (2008) Peatlands and carbon. In: Parish, F., Sirin, A., Charman, D., Joosten, H.,
Minaeva, T. and Silvius, M. (eds). Assessment on peatlands, biodiversity and climate change. Global
Environment Centre, Kuala Lumpur and Wetlands International Wageningen, pp. 99-117.
Mitra, S., Wassmann, R. & Vlek, L.G. (2005) An appraisal of global wetland area and its organic carbon stock.
Current Science 88: 25–35.
The Ramsar Convention on Wetlands. The Convention on Wetlands text, as amended in 1982 and 1987.
http://www.ramsar.org/cda/en/ramsar-documents-texts-convention-on/main/ramsar/1-3138%5E20671_4000_0__

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