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CHAPTER 1

INTRODUCTION

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Tom Wirth (USA) and Chengyi Zhang (China)

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Lead Authors

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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)

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Contributing Authors

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

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Review Editors

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Fatih Evrendilek (Turkey) and Steen Gyldenkærne (Denmark)

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† Ms. Tuija Elina Lapvetelainen, a close colleague, passed away in July 2013. She greatly contributed to the development of
Chapter 1.

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1.1

Background ............................................................................................................................................ 3

1.2

Guidance for using this supplement ....................................................................................................... 3

1.3

Application of the Managed Land Proxy to wetlands ............................................................................ 8

1.4

Coherence and compatibility with 2006 IPCC Guidelines ................................................................... 10

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1.4.1
Guidance on activities in the 2006 IPCC Guidelines that are also covered in the Wetlands
Supplement ................................................................................................................................................... 10

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1.4.2
1.5

Supplementary guidance in this report .......................................................................................... 11
Relevant databases for wetlands and organic soils ............................................................................... 15

Figures

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Decision tree for finding the appropriate guidance chapter within the Wetlands Supplement
Figure 1.1
or the 2006 IPCC Guidelines .................................................................................................................. 4

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Figure 1.2

Soil based subcategories that are being addressed in the Wetlands Supplement ..................... 533

Figure 1.3

Typical management practices on organic and wet soils......................................................... 9

Tables34

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Table 1.1 Look-up table for Wetlands Supplement cross-referenced to land-use categories, soil type andcondition (wet, recently drained, dry), and inland or coastal location................................................... 1437
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Table 1.2 Global and regional on-line resources that provide metadata sets for developing an inventory ofgreenhouse gas emissions and removals from wetlands and organic soils............................................ 15

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1 INTRODUCTION

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1.1

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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 CO2
emissions 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 issufficient 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.

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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 andwith wet mineral soils in Wetlands and other land-use categories with these soil types that are subject to humanactivities (‘managed’). The Wetlands Supplement is organized into the following chapters:

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Chapter 2: Drained Inland Organic Soils

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Chapter 3: Rewetted Organic Soils

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Chapter 4: Coastal Wetlands

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Chapter 5: Inland Wetland Mineral Soils

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Chapter 6: Constructed Wetlands for Wastewater Treatment

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Chapter 7: Cross-Cutting Issues and Reporting

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1.2

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This introductory chapter provides guidance on how to use this Wetlands Supplement in conjunction with theexisting 2006 IPCC Guidelines when preparing a greenhouse gas inventory that includes land with organic or
wet mineral soils across all IPCC land-use categories. The decision tree (Figure 1.1) can be used by inventory
compilers 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 below.
The notes explain and illustrate the terms used in the decision tree and in this document (see also the glossary).

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The terms are for the purpose of this document and their definitions are not intended to pre-empt otherdefinitions of these terms in other contexts. For example: Except for in the name of this supplement, thisguidance uses the term ‘Wetlands’ (with capital ‘W’ and always plural) solely when referring to the IPCC landuse category Wetlands. The terms ‘wetland’ or ‘wetlands’ (with lowercase ‘w’ and singular or plural) are used torefer to land with wet soil as defined in note 3 below. Other articulations of the ‘wetland’ concept are possible
e.g. that used by the Ramsar Convention (www.ramsar.org/cda/en/ramsar-documents-texts-conventionon/main/ramsar/1-31-38%5E20671_4000_0__) but this does not affect the methodological guidance provided.

BACKGROUNDGUIDANCE FOR USING THIS SUPPLEMENT

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Figure 1.1

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

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Note 1: Determine land-use category

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The Wetlands Supplement covers land with wet and dry organic soils and wet and recently drained mineral soils(see notes 2, 3, and 4 for the definition of these terms) across all IPCC land-use categories (Forest Land,
Cropland, Grassland, 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 inthat it does not change the assignment of land to a category. If using Approach two or three for the land
representation 1 , land-use conversions (e.g., Forest Land converted to Cropland, Cropland converted toSettlements) should also be identified.

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Compared to the 2006 IPCC Guidelines the Wetlands Supplement identifies relevant subcategories (see Figure
1.2 below) and specifies emission factors for all land-use categories with organic, wet mineral or recently
drained mineral soils. The Wetlands Supplement also differentiates coastal land from inland land, because watersalinity and dynamics (e.g., tides) may, for the same land-use category, modify emission factors compared toinland land.

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Figure 1.2

Soil based subcategories that are being addressed in the Wetlands Supplement

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Notes on Figure 1.2: Guidance for all the soils shown in this figure is included the Supplement except for the ‘mineral dry’ soils thatare not ‘recently drained’ (see note 4). Guidance for ‘mineral dry’ soils that are not ‘recently drained’ is provided in the 2006 IPCC
Guidelines.

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It is good practice to subdivide each land use/conversion category into subcategories with similar characteristics.
The Wetlands Supplement proposes a division into four soil subcategories; all with a coastal and inland
subdivision where appropriate (see Figure 1.2 above):

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1)

dry mineral soil (with the subdivision ‘recently drained’)

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wet mineral soil

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wet organic soil

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drained (dry) organic soil.

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In the case where dry (but not recently drained, see note 4) mineral soil remains dry mineral soil, use theguidance in the 2006 IPCC Guidelines on soil carbon estimation in the Forest Land, Cropland or Grassland
Chapters as appropriate. In all other cases (including the case of ‘recently drained mineral soil’, i.e. a dry mineralsoil that has recently originated from a wet mineral soil, and the case of the conversion of a dry mineral soil to a
wet mineral soil), use the decision tree (see Figure 1.1 above) to identify the appropriate guidance chapter within
this Wetlands Supplement or the 2006 IPCC Guidelines

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The 2006 IPCC Guidelines are used for estimating and reporting anthropogenic greenhouse gas emissions andremovals only. With respect to ‘land’ this requires inventory compilers to differentiate between ‘managed’ and1

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

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‘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 case of coastal wetlands, guidance is provided to estimate andreport countries’ emissions and removals from specific management activities.

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Note 2: Is the soil organic?

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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):

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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.

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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.

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For peat and peatland, no IPCC definitions exist. Definitions of peatland and peat soil differ between countries
with respect to how thick the peat layer must be to call something a peatland or a peat soil. Also the definition ofpeat varies among countries and disciplines, especially with respect to the minimum percentage of organic
matter the material has to contain (Joosten and Clarke, 2002). In the Wetlands Supplement the concept of
peatland is considered to be included in ‘(land with) organic soil’.

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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.

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Note 3: Is the soil wet?

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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,
particularly soil microbes and rooted plants, adapted to anaerobic conditions control the net annual greenhousegas emissions and removals. Every soil that is not a wet soil is classified as a dry soil (see also note 4).

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With respect to soil wetness, for the tier 1 approach this Wetlands Supplement differentiates only between wet
soil and dry soil. Dry soils generally do not emit methane, but do emit nitrous oxide, whereas wet soils generally
do not emit nitrous oxide, but do emit methane. As methane, carbon dioxide and nitrous oxide emissions canvary with water table depth (see Chapters 2 and 3 of this Wetland Supplement), it is good practice to differentiate
more finely amongst water level classes in higher tiers. It should also be noted that flooded (paddy) rice (even on
earlier drained land) is considered to be wet soil.

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A wetland is an area of land with a wet soil. It is good practice that – when a country uses another concept ofwetland in accordance with its national circumstances – the definition of wetland (and its possible subdivisions)applied is clearly defined and applied consistently both across the entire national land area and over time.

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Rewetting is the process of changing a drained soil (see note 4) into a wet soil. A rewetted soil is a soil thatformerly has been a drained soil but as a result of human intervention has become a wet soil.

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Restoration (adjective restored) is the process of assisting the recovery of an ecosystem that has been degraded,
damaged, or destroyed. In case of drained former wetlands, restoration always has to include rewetting.

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Note 4: Is the soil recently drained?

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Drainage is the process of changing a wet soil (see note 3) into a dry soil (see note 3). A drained soil is a soil thatformerly has 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, so that a dry organic soil always is also a drained organic soil.

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Recently drained mineral soils may have a ‘memory’ of the former wet soil conditions (i.e. a high organic
content) that may make their greenhouse gas emission characteristics different from mineral soils that always

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have been dry. These differences fade out with progressing time after drainage due to the loss of carbon from the
aerobic part of the soil. As long as these differences in emission exist, the soil is considered to be ‘recently
drained’.

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Tier 1 does not distinguish such transition period for organic soils, that is, it does not differentiate between
recently and long-time drained organic soils. In organic soils the amount of carbon in the aerobic part of the soil
does not substantially decrease as long as the soil remains both ‘drained’ and ‘organic’.

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Note 5: Soil under rice cultivation

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It is good practice to separate rice cultivation on mineral soils from that on organic soils. For cultivation onmineral soils the emissions are determined using the 2006 IPCC Guidelines. For cultivation on tropical organicsoils emission factors for CO2, methane (CH4) and N2O are presented in Chapter 2 of the Wetlands Supplement.

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Note 6: Is this a ‘Flooded Land’?

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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).

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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, Volume 4 of the 2006 IPCC Guidelines.
Reservoirs constructed as wetlands for wastewater treatment are covered in Chapter 6 of the Wetlands
Supplement.

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Note 7: Is this a wetland for wastewater treatment?

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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 that purpose (constructed wetlands for wastewater treatment) and for natural wetlands that areused for or influenced by wastewater treatment. The emissions are reported under the Waste Sector. Other
constructed (i.e., man-made, engineered or artificial wetland creation) wetlands are included in Chapter 5 of the
Wetlands Supplement.

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Note 8: Is this coastal land?

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Coastal land is land at or near the coast. It is good practice that a country clearly defines the concept of ‘coastal
land’ and its sea- and landward limits in accordance with its national circumstances and applies that definition
consistently both across the entire national land area and over time. All land that is not coastal is inland.

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The types of land of interest here include coastal wetland (with both primary wet soil and rewetted soil, see note
3) and recently drained former coastal wetland (see note 4).

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A coastal wetland is a wetland (see note 3) on coastal land that is influenced by saline or brackish water and/or
astronomic tides. Coastal wetland may occur on both organic and mineral soils. Brackish/saline water is waterthat normally contains more than 5 or more parts per thousand (ppt) of dissolved salts. Every mineral soil
wetland that is neither a coastal wetland (see note 8), nor a Flooded Land (see note 6) nor a constructed wetland(see note 7) for waste water treatment is classified as inland wetland (cf. Chapter 5).

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Note 9: Is this inland mineral soil?

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Inland mineral soil is all mineral soil (see note 2) that is not on coastal land (see note 8). The types of land ofinterest that are likely to be identified include inland mineral soil wetland (with both primary wet soils andrewetted soils, see note 3) and recently drained former inland mineral soil wetland (see note 4).

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An inland mineral soil wetland is every wetland (see note 3) on mineral soil (see note 2) that is neither a coastal
wetland (see note 8), nor a Flooded Land (see note 6) nor a constructed wetland for wastewater treatment (seenote 7). Inland mineral soil wetlands may have brackish/saline water (see note 8).

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Note 10: Is this organic soil wet?

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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, theseare discussed in the general discussion and in the higher tier sections of that chapter. Chapter 2 of the Wetlands
Supplement covers drained (dry) organic soils.

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

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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 or 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 in this Wetlands Supplement.

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Draining inland organic soils lowers the water table and increases the oxygen content of the soil,
thus increasing CO2 emissions. 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
sources of CH4 to the atmosphere. Drained organic soils can also emit significant amounts of N2O
from nitrogen in the organic matter or nitrogen added by fertilization. Removals of particulate anddissolved 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 close to zero, and increases CH4 emissions
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 emissions are greatly reduced or evenbecome negative and the wetlands function as a net remover of greenhouse gases from theatmosphere (Chapter 3 of this supplement). CO2 emissions from coastal wetlands can besignificant 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 areenriched with nutrients from agricultural run-off or sewage (Chapter 4 of this supplement).
Restoring and creating wetlands on mineral soils, similar to rewetting organic soils, creates anoxic
conditions and increases CH4 emissions (Chapter 5 of this supplement). Constructed and seminatural wetlands used for wastewater treatment emit CH4 and N2O (Chapter 6 of this supplement).

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APPLICATION OF THE MANAGED LANDPROXY TO WETLANDS

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The 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.

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The Managed Land Proxy continues to be applied in the Wetlands Supplement. For coastal wetlands (Chapter 4of this supplement), where non-anthropogenic emissions and removals are often significantly greater than theanthropogenic fluxes, this Wetlands Supplement provides guidance to estimate and report countries’ emissions
and removals from specific management activities (e.g., aquaculture, salt production, dredging). See Figure 1.3
below for some typical management practices on wetlands.

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Figure 1.3

Typical management practices on organic and wet soils

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COHERENCE AND COMPATIBILITY WITH
2006 IPCC GUIDELINES

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This section provides an overview of the linkages 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 that are the topic of additional guidance in this supplement. Section 1.4.2, highlights the guidance inthis supplement that was not previously included in the 2006 IPCC Guidelines and may need to be considered byinventory compilers.

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1.4.1

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

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CARBON STOCK CHANGES IN MINERAL AND ORGANIC SOILS

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The 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 is applied that is differentiated by climate region
and land use. The Wetlands Supplement provides additional guidance for both organic and wet mineral soils that
may need to be considered. Mineral soils are sub-divided into dry mineral soils (not subject of the Wetlands
Supplement), wet mineral soils and recently drained mineral soils. The information with respect to organic soils
is expanded to include activities on wet (undrained, rewetted or restored) 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 provide CO2 emission factors for drained organic soils, isupdated in Table 2.1 in the Wetlands Supplement.

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CH 4 EMISSIONS FROM MANAGED SOILS

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Section 2.3.3.1, Chapter 2 in Volume 4 of the 2006 IPCC Guidelines assumes CH4 emissions due to the drainage
of organic soils are negligible. The Wetlands Supplement provides guidance on estimating CH4 emission fromdrained organic soils and drainage ditches, including default emission factors in Table 2.3 and 2.4 in Chapter 2,
respectively.

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The 2006 IPCC Guidelines do not provide guidance on estimating CH4 emissions from mineral soils except forrice 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.

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BIOMASS AND DEAD ORGANIC MATTER CARBON STOCK CHANGES

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The generic 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.

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The Wetlands Supplement does not provide additional guidance for these pools in Chapters 2, 3 and 6. The
Wetlands Supplement provides new emission factors for carbon stock changes in biomass, dead organic matterand for soils for those associated with activities that occur in coastal wetlands (Section 4.2, Chapter 4). New
stock change factors are provided for inland wet mineral soils (Section 5.3, Chapter 5).

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DIRECT AND INDIRECT N 2 O EMISSIONS FROM MANAGED SOILS

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In Section 11.2, Chapter 11 in Volume 4 of the 2006 IPCC Guidelines, methodologies are provided to estimate
both direct and indirect N2O emissions from managed soils. Generic equations are presented that can be applied
to all land areas in aggregate or to specific land-use categories if activity data are available. N2O emissions fromdrained organic soils are estimated using an area-based annual emission factor differentiated by climate region.
The 2006 IPCC Guidelines cautions of the risk of double counting of indirect N2O emissions that are reported
elsewhere, e.g. under Agriculture (Chapter 11, Volume 4) or under Industry (Section 7.3, Chapter 7 in Volume1). This caution is reiterated here with regard to the use of the additional information about N2O emissions,

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Certain Tier 1 N2O emission factors provided in Tables 11.1 (direct emissions), Chapter 11 in Volume 4 of the2006 IPCC Guidelines are updated Table 2.5, Chapter 2 in the Wetlands Supplement.

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NON-CO 2 EMISSIONS FROM BIOMASS BURNING

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Generic guidance for non-CO2 emissions due to 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 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 burning of organic soils.

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RICE CULTIVATION

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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.

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WETLANDS

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In the Wetlands chapter of the 2006 IPCC Guidelines (Chapter 7 in Volume 4), methodologies are provided 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 this Wetlands Supplement.

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The 2006 IPCC Guidelines (Volume 4, Chapter 7) provide guidance for estimating CO2 emissions fromreservoirs or impoundments used for hydroelectricity production, irrigation, navigation, or recreation (Section
7.3). This guidance, however, is restricted to CO2 emissions from land converted to flooded land, i.e., where
human activities have caused an increase in area covered by water. Regulated lakes and rivers that do not havesubstantial changes in water area in comparison with the pre-flooded ecosystem are not considered flooded land.
No additional guidance relative to that in the 2006 IPCC Guidelines (Chapter 7 in Volume 4) is provided in this
Wetlands Supplement for cases where the management of reservoirs or impoundments for water supply fulfil thedefinition of Flooded Land.

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WASTEWATER TREATMENT

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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 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.

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1.4.2

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

Supplementary guidance in this report

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CHAPTER 2—DRAINED INLAND ORGANIC SOILS

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Chapter 2 in the Wetlands Supplement provides an updated summary of emission factors and supplementary
guidance to Volume 4 of the 2006 IPCC Guidelines on estimating greenhouse gas emissions and removals fromdrained inland organic soils for all land-use categories: Forest Land, Cropland, Grassland, Wetlands, Settlements
and Other Land, (see Figure 1.3, Frame B in this chapter).

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Additional Tier 1 guidance is provided to include the impact of drainage depth (water-table level) on theemission of CO2, CH4 and N2O. New emission factors to estimate the release of CH4 from drainage ditches arealso provided.

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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 provide Tier 1 methodologies for emissions
associated with POC or DIC. However, Annex 2A.1, Chapter 2 in the Wetlands Supplement sets out the basis for
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 theburning, 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.

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CHAPTER 3—REWETTED INLAND ORGANIC SOILS

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Chapter 3 in the Wetlands Supplement provides new guidance and emission factors for organic soils that had
been drained for forestry, crop production, grazing, peat extraction or other purposes, and subsequently havebeen 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.,
restoration of damaged vegetation cover), in the majority of cases restoration will include rewetting.

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Chapter 3 provides Tier 1 guidance for assessing the greenhouse gas (CO2, CH4 and N2O) emissions andremovals from rewetted organic soils by climate region and general guidance for utilizing higher tiermethodologies.

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CHAPTER 4—COASTAL WETLANDS

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Chapter 4 in the Wetlands Supplement provides guidance on estimating emission and removals of greenhousegases (CO2, CH4 and N2O) associated with specific activities on managed coastal wetlands, which may or may
not result in a land use change. Coastal wetlands are wetlands near the coast that are influenced by tidal and/or
saline or brackish water. They may consist of mangrove, tidal marsh and seagrass vegetation and can haveorganic and mineral soils (see Figure 1.3, Frame A in this chapter). Management practices included in theguidance are aquaculture, salt production, extraction, drainage, rewetting and revegetation, and forest
management activities in mangroves.

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CHAPTER 5—INLAND WETLAND MINERAL SOILS

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Chapter 5 in the Wetlands Supplement provides guidance for inland managed lands with wet mineral soils notincluded in Chapter 4 (coastal wetlands) or Chapter 6 (constructed wetlands for wastewater treatment) in the
Wetlands Supplement, and for recently drained inland mineral soils. The chapter provides methodologies for
estimating greenhouse gas emissions and removals, gives updated default reference values for soil organiccarbon stocks and offers a default stock change factor for land use for long term cultivation of croplands on
inland wet mineral soils. It also gives guidance 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 have been inundated for the
purpose of wetland creation.

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Chapter 5 in the Wetlands Supplement does not provide guidance on the application of the methodology from
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 estimates

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of the loss of soil carbon in relation to the updated and new defaults for SOCREF and SOC stock change factors.
But the Chapter suggest a future development on the issue.

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CHAPTER 6—CONSTRUCTED WETLANDS FOR WASTEWATERTREATMENT

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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 onwastewater 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. The inventory compiler is encouraged to consider guidance in the 2006 IPCC
Guidelines and in the Wetlands Supplement for possible approaches to reporting these carbon pools.

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CHAPTER 7—CROSS-CUTTING ISSUES AND REPORTING

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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 summarizes 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 the 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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OVERVIEW OF GENERAL CONSIDERATIONS IN USING THE WETLANDSSUPPLEMENT AND THE 2006 IPCC GUIDELINES

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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.

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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 that are already addressed as indirect emissions from soil amendments (e.g., nitrogen fertilizers) within
Chapter 11 in Volume 4 of the 2006 IPCC Guidelines. This risk can be avoided by using as activity data only Nthat is originates directly as a result of the activities discussed here.

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Chapter 2 of this supplement provides guidance on waterborne carbon (DOC, DIC and PIC), However,waterborne carbon may already be included in a country’s emission estimates if the country uses a methodology
in which soil carbon stock changes are measured in situ (e.g., soil sampling associated with forest inventories).

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Table 1.1 below provides guidance on which chapters of this Wetlands Supplement are relevant when theinventory compiler is considering particular combinations of land use and soil type and soil condition. Where no
guidance is provided in this Wetlands Supplement the table is blank. Table 1.1 does not provide guidance for the2006 IPCC Guidelines. For example, Grasslands on wet mineral soils in Table 1.1 refers to Chapter 5 of this
Wetlands Supplement. However in many cases this Wetlands Supplement only provides additional guidance on asubset of the particular land use, soil type, and soil condition combinations listed in Table 1.1. To estimate total
greenhouse gas emissions from organic and wet soils correctly, this Wetlands Supplement should be referenced
together with the 2006 IPCC Guidelines.

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TABLE 1.1
LOOK-UP TABLE FOR WETLANDS SUPPLEMENT CROSS-REFERENCED TO LAND-USE CATEGORIES, SOIL TYPE AND CONDITION (WET, RECENTLY DRAINED, DRY), AND INLANDOR COASTAL LOCATION

Forest land
Soil Type

Cropland

Grassland

Wetlands

Settlements

Other Land

Gas
InlandCoastalInlandCoastalInlandCoastalInlandCoastalInlandCoastalInlandCoastalCO2
Mineral Dry

Dry

CH4
N2O

MineralMineral Recently
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

N2O
Mineral Wet

Organic wet
Organic
Organic Dry(Drained)

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

N2O

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

N2O

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

N2O

2

2

2

2

2

2

Wet

Dry

Constructed andNatural 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 asappropriate and the impact on biomass, soil carbon and other pools may be considered. Care is required to avoid double-counting of emissions.

Emissions due toburning 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 beapplied 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 some guidance on carbon loss from organic soils through water pathways. The informationis relevant to all land use categories.

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1.5

RELEVANT DATABASES FOR WETLANDSAND ORGANIC SOILS

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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.

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Inventory compilers may be able to collect activity data from in-country natural resource agencies or national
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 toinventory compilers in obtaining activity data for estimating greenhouse gas emissions and removals from thewetlands and organic soils included in this Wetlands Supplement. The most notable wetlands dataset is theRamsar database of the Ramsar Convention. For most ‘wetlands of international importance,’ the Ramsar
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 avariety of metadata sets, including forestry, agriculture, and carbon emissions at 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 offer open source geospatial data. Wetlands International is the
only global NGO that focuses on wetland best practices, restoration and conservation. This organization 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 THAT PROVIDE METADATA SETS FOR DEVELOPING AN INVENTORY OF
GREENHOUSE GAS EMISSIONS AND REMOVALS FROM WETLANDS AND ORGANIC SOILS

Online Resources

Description

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

The Convention on Wetlands of International Importance, called 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 consists 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 on conservation in general. It
also contains several atlases of wetlands, e.g. World Mangrove
Atlas, and World Atlas of Seagrass

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/

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.

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References

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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

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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.

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IPCC. (2011). IPCC Expert Meeting on HWP, Wetlands and Soil N2O. Geneva, Switzerland: eds:Eggleston,
H.S.; Srivastava, N.; Tanabe, K; Baasansuren, J.; Fukuda, M. IGES, Japan 2011. http://www.ipccnggip.iges.or.jp/meeting/pdfiles/1010_MeetingReport_AdvanceCopy.pdf

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Joosten, H. and 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

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Joosten, H. and Couwenberg, J. (2008). Peatlands and carbon. In: Parish, F., Sirin, A., Charman, D., Joosten, H.,
Minaeva, T. and Silvius, M. (eds) 2008. Assessment on peatlands, biodiversity and climate change. Global
Environment Centre, Kuala Lumpur and Wetlands International Wageningen, pp. 99-117.

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Mitra, S., Wassmann, R. and Vlek, L.G. (2005). An appraisal of global wetland area and its organic carbon stock.
Current Science 88: 25–35.

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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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