DO NOT CITE OR QUOTE

Overview
Final Draft

1
2
3
4

5
6
7

2013 SUPPLEMENT TO THE 2006
IPCC GUIDELINES FOR
NATIONAL GREENHOUSE GASINVENTORIES: WETLANDS

Methodological Guidance on Lands with Wet andDrained Soils, and Constructed Wetlands for
Wastewater Treatment

8
9
10
11
12
13
14
15
16
17

DRAFT 2013 Wetlands Supplement

1Overview

DO NOT CITE OR QUOTE

Final Draft

18

OVERVIEW

1920
21

Authors

22
23
24
25

Dominique Blain (Canada), Rizaldi Boer (Indonesia), Simon Eggleston (TFI-TSU1), Sergio Gonzalez (Chile),
Takahiko Hiraishi (Japan), William Irving (USA), Thelma Krug (Brazil), Alex Krusche (Brazil), EmmanuelJonathan Mpeta (Tanzania), Jim Penman (UK), Riitta Pipatti (Finland), Robert Sturgiss (Australia), Kiyoto
Tanabe (TFI-TSU), Sirintornthep Towprayoon (Thailand)

26

Review Editors

27

Steen Gyldenkærne (Denmark), Erda Lin (China)

28
29

30

Contents

31
32

1 Introduction ....................................................................................................................................................... 333

1.1 Background................................................................................................................................................ 334

2 Coverage of the Wetlands Supplement .............................................................................................................. 535

3 Managed Land and Anthropogenic Emissions .................................................................................................. 736

4 The Wetlands Supplement and the 2006 IPCC Guidelines ............................................................................... 8

37
38

1

2

Until February, 2013.

DRAFT 2013 Wetlands Supplement

DO NOT CITE OR QUOTE

Overview
Final Draft

39

1 INTRODUCTION

40
41
42
43
44
45
46
47
48

The 2013 Supplement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories: Wetlands(Wetlands Supplement) provides methods for estimating anthropogenic emissions and removals of greenhousegases from wetlands. The term wetlands is taken to refer to lands with wet and drained soils, and constructedwetlands for wastewater treatment. This is broader than the coverage in the 2006 IPCC Guidelines for National
Greenhouse Gas Inventories2 (2006 IPCC Guidelines), where managed wetlands are defined as lands where thewater table is artificially changed (e.g. drained or raised) or those created through human activity (e.g. damminga river) and that are not Forest Land, Cropland, Grassland or Settlements. The emissions and removals fromwetlands addressed in the Wetlands Supplement can occur under any land-use category or other relevant categoryof the 2006 IPCC Guidelines.

49
50
51
52
53
54
55

The guidance provided is supplementary to that contained in the 2006 IPCC Guidelines, which provide
methodologies for estimating national anthropogenic emissions by sources and removals by sinks of greenhousegases not controlled by the Montreal Protocol. 3 The content of the 2006 IPCC Guidelines on wetlands is
restricted to peatlands drained and managed for peat extraction, conversion to flooded lands, and some guidancefor drained organic soils. It is therefore incomplete; it does not cover all wetlands types and does not characterize
all of the significant activities occurring on the wetlands that it does cover (e.g., rewetting of peatlands is notincluded).

56
57
58
59
60
61

This Wetlands Supplement supplements the 2006 IPCC Guidelines by filling in gaps in the coverage andproviding updated information reflecting scientific advances. This includes updating of default emission factors.
It covers inland peatlands and other wetlands on mineral soils, coastal wetlands including mangrove forests, tidal
marshes and seagrass meadows, and constructed wetlands for wastewater treatment. For the reasons described
subsequenlty, the Wetlands Supplement does not provide guidance on permanently flooded lands such as
reservoirs4.

62

1.1

63

The Expert Meeting on HWP, Wetlands and Soil N2O held on 19th-21st October, 2010 in Geneva, concluded that:

64
65
66
67
68
69

Since the 2006 IPCC Guidelines were completed much new scientific information is now
available about various wetlands that enable emissions and removals to be estimated fromwetland restoration and rewetting especially for peat lands. The meeting recommended that
the IPCC provide additional methodological guidelines for the rewetting and restoration ofpeat land; emissions from fires, ditches and waterborne carbon; and constructed wetlands
for waste water disposal, to fill gaps in the existing guidelines.

70
71
72
73
74

This Wetlands Supplement has been produced in response to the conclusions of this expert meeting, and in
response to an invitation from the Subsidiary Body for Scientific and Technological Advice (SBSTA) of theUnited Nations Framework Convention on Climate Change (UNFCCC) at its 33rd session, held in December
2010 in Cancun, which invited the IPCC to prepare additional guidance on wetlands, focusing on the rewetting
and restoration of peatlands. Document FCCC/SBSTA/2010/13, paragraph 72 states:
2

BACKGROUNDIntergovernmental Panel on Climate Change (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. andTanabe K. (eds). Published: IGES, Japan.

3 Greenhouse gases addressed in this Supplement are: CO2, CH4, and N2O.
4 Regarding permanently flooded lands, participants at an IPCC Expert Meeting “... did not agree that there was now
sufficient new information available to produce new and additional guidelines based on the latest literature. They did,
however, agree on the need to discuss a range of associated issues, such as the impact of reservoirs on total emissions fromwatersheds, allocation of emissions to specific drivers and how emissions may be related to specific reservoir typologies.”
see IPCC 2011, IPCC Expert Meeting on HWP, Wetlands and Soil N2O eds: Eggleston H.S., Srivastava N., Tanabe K.,
Baasansuren J., and Fukuda M. Meeting Report of the IPCC Expert Meeting on HWP, Wetlands and Soil N2O, Geneva,
Switzerland, 19-21 October, 2010, Pub. IGES, Japan 2011

DRAFT 2013 Wetlands Supplement

3Overview

DO NOT CITE OR QUOTE

Final Draft
75
76
77
78
79

...the SBSTA invited the IPCC to undertake further methodological work on wetlands,
focusing on the rewetting and restoration of peatland, with a view to filling in the gaps in the2006 IPCC Guidelines for National Greenhouse Gas Inventories (hereinafter referred to as
the 2006 IPCC Guidelines) in these areas and to complete this work for the thirty-ninth
session of the SBSTA.

80
81
82

In response to this invitation, the IPCC held a scoping meeting in Geneva, Switzerland, from 30th March to 1st
April, 2011. This meeting produced a draft Terms of Reference (ToR), including annotated chapter outline,
which was approved by the IPCC at its 33rd Session in Abu Dhabi (10th-13th May 2011).

83
84
85
86

4

DRAFT 2013 Wetlands Supplement

DO NOT CITE OR QUOTE

Overview
Final Draft

88

2 COVERAGE OF THE WETLANDSSUPPLEMENT

89
90
91
92
93
94
95
96

The 2006 IPCC Guidelines classify all land area into six broad land-use categories: Forest Land, Cropland,
Grassland, Settlements, Wetlands and Other Land (see Chapter 3, Volume 4 of the 2006 IPCC Guidelines). The
lands covered in the Wetlands Supplement may occur in any of the IPCC land-use categories. The land-use
category that land is reported under depends on national land-use category definitions, data collection systems
and tracking of land transitions. For example, forested peatland can be classified as Forest Land, plantations on
peatland may be classified as Forest Land or Cropland depending on national forest definitions, and mangrove
forests may be classified as Forest Land or Wetlands. Due to its function, Constructed Wetlands are notconsidered as a land-use category. The coverage of the Wetlands Supplement is briefly summarized in Table 1.

87

97

TABLE 1
COVERAGE OF THE WETLANDS SUPPLEMENT
Chapter

Coverage

1.

Introduction

Introduction of this report. Guidance on this report usage and Genericinformation application of the managed land proxy in wetlands, thelinkages between the 2006 IPCC Guidelines and the supplementary
guidance presented in this document.

2.

Drained Inland Organic Soils

Guidance for managed inland organic soils including land drained forforestry, croplands, grazing, and settlements across climate zones.

3.

Rewetted Organic Soils

Guidance on rewetted organic soils including boreal, temperate, andtropical wetlands occurring in any land-use category.

4.

Coastal Wetlands

Guidance for specified management activities in coastal areas ofmangroves, tidal marshes and seagrass meadows.

5.

Inland Wetland Mineral Soils

Guidance for managed inland wetland mineral soils, including lands
used for forestry, cropland, grazing, and settlements, and rewetted
mineral soils.

6.

ConstructedWetlands
Wastewater Treatment

7.

Cross-cutting Issues and Reportingfor

Guidance on wetlands constructed for wastewater treatment.

Overall guidance on how to report anthropogenic emissions andremovals from wetlands in the framework of the 2006 IPCC
Guidelines. Also gives general good practice guidance on cross-cutting
issues (key category and uncertainty analysis, times series consistency
and QA/QC) to supplement that given in Volume 1 of the 2006 IPCC
Guidelines.

98
99
100
101

A summary of the main methodological updates to the 2006 IPCC Guidelines is provided below. Chapter 1
provides a decision tree to help inventory compilers determine which chapters of this supplement to apply anddescribes the coverage and definitions of the wetland types.

102
103
104
105
106
107
108

Peatlands and organic soils. The 2006 IPCC Guidelines included some guidance on drainage (Chapter 4,
Volume 4) and peat extraction (Chapter 7, Volume 4), but not on rewetting. In this supplement, peatlands areincluded along with organic soils and both drainage and rewetting are covered. Updated default emission factors
and methods are provided for both drained and rewetted organic soils including for off-site carbon dioxide (CO2)emissions via waterborne carbon losses. Guidance on methane (CH4) emissions from rewetting of organic soils(Chapter 3), ditches on drained inland organic soils and CO2, CH4 and carbon monoxide (CO) emissions frompeat fires are also provided (Chapter 2).

DRAFT 2013 Wetlands Supplement

5Overview

DO NOT CITE OR QUOTE

Final Draft
109
110

Peatland managed for peat production. Peat production is covered in the 2006 IPCC Guidelines (Chapter 7,
Volume 4) and no additional guidance is given here except some updated emission factors in Chapter 2.

111
112

Rice cultivation. Rice cultivation is covered in the 2006 IPCC Guidelines (Chapter 5, Volume 4) and additionalemission factors for lowland rice production are given in Chapter 2.

113
114
115
116
117

Coastal wetlands. The 2006 IPCC Guidelines provided no specific guidance for coastal wetlands and new
guidance is given in Chapter 4 on how to treat anthropogenic emissions and removals associated with specified
human activities that affect them. Coastal wetlands in this supplement include mangrove forests, tidal marshes
and seagrass meadows. Default emissions factors and methodologies are provided for management of mangrove
forests (i.e. harvesting), rewetting and revegetation, aquaculture and drainage.

118
119
120
121
122
123

Inland wetland mineral soils (IWMS). The 2006 Guidelines provided limited data on soil C in wetland mineralsoils. Chapter 5 provides updated default soil carbon factors and covers methodologies for quantifying emissions
and removals of CO2 and emissions of CH4 from (i) artificial drainage of IWMS (ii) subsequently rewetting ofartificially drained IWMS and (iii) the artificial flooding of mineral soils for the purposes of wetland creation.
Mineral soil wetlands5 include riparian wetlands, forested swamps and marshes and can occur in all climate
zones.

124
125
126
127

Saline inland wetlands. Saline wetlands are important parts of otherwise arid landscapes across the globe but
little information is available in the literature to assess potential greenhouse gas emissions or removals fromthese lands. Thus default factors cannot be given and no guidance is provided for these wetland types. These
are also known as playas, pans, salt lakes, brackish wetlands, salinas, and sabkhas.

128
129
130
131

Constructed wetlands for wastewater treatment. The guidance supplements Volume 5 of the 2006 IPCC
Guidelines on Waste (Chapter 6). These are wetlands that have been designed and constructed to use naturalprocesses involving vegetation, soils, and associated microbial assemblages to treat wastewater. New guidance isalso provided on semi-natural treatment wetlands.

132
133
134
135

Permanently flooded lands. No new guidance on permanently flooded lands is provided. The Expert Meeting on
6
HWP, Wetlands and Soil N2O concluded that insufficient new information has become available7. The IPCC
8Special Report on Renewable Energy Sources and Mitigation of Climate Change also noted that it was notpossible to make global estimates of the size of emissions from reservoirs.

5

Wetlands do not all have organic soils. Wetland Mineral Soils are classified as Aquic soil (USDA) or Gleysols (World
Reference Base), and are described as having restricted drainage leading to periodic flooding and anaerobic conditions(Table 2.3, Chapter 2 of the 2006 IPCC Guidelines).

6

IPCC 2011, IPCC Expert Meeting on HWP, Wetlands and Soil N2O eds: Eggleston H.S., Srivastava N., Tanabe K.,
Baasansuren J., and Fukuda M. Meeting Report of the IPCC Expert Meeting on HWP, Wetlands and Soil N2O, Geneva,
Switzerland, 19-21 October, 2010, Pub. IGES, Japan 20117

The attendees of the Expert Meeting on HWP, Wetlands and Soil N2O agreed that, before additional guidance could be
developed for permanently flooded lands, there needed to be consensus on issues such as: the impact of reservoirs on total
emissions from watersheds, allocation of emissions to specific drivers, and how emissions may be related to specificreservoir typologies.

8

IPCC, 2011: IPCC Special Report on Renewable Energy Sources and Climate Change Mitigation. Prepared by Working
Group III of the Intergovernmental Panel on Climate Change [O. Edenhofer, R. Pichs-Madruga, Y. Sokona, K. Seyboth, P.
Matschoss, S. Kadner, T. Zwickel, P. Eickemeier, G. Hansen, S. Schlömer, C. von Stechow (eds)]. Cambridge University
Press, Cambridge, United Kingdom and New York, NY, USA, 1075 pp.

6

DRAFT 2013 Wetlands Supplement

DO NOT CITE OR QUOTE

Overview
Final Draft

137

3 MANAGED LAND AND ANTHROPOGENICEMISSIONS

138
139
140
141
142
143
144
145

Parties to the UNFCCC have committed to report anthropogenic emissions and removals of greenhouse gases
not covered by the Montreal Protocol.9 In practice, it is difficult to separate anthropogenic and natural emissions
in Agriculture, Forestry and Other Land-Use (AFOLU). Thus, the 2006 IPCC Guidelines provides that it is goodpractice to report emissions and removals from managed land as a proxy for anthropogenic emissions and10
removals (Pages 1.4-1.5, Chapter 1, Volume 4 of the 2006 IPCC Guidelines). An expert meeting held in May
2009 in Brazil, reconsidered the issue and concluded that, although suitable methods for a better quantificationof anthropogenic emissions and removals had been demonstrated in specific circumstances, there was no suitable,
globally applicable alternative to the use of managed land as a proxy for anthropogenic emissions and removals.

146
147
148
149
150
151
152
153
154
155
156
157

The authors agree that the use of managed land as a proxy for anthropogenic emissions and removals should
continue. They also noted that many wetlands on managed land have significant non-anthropogenic fluxes ofgreenhouse gases. The 2006 IPCC Guidelines restricted managed wetlands to those lands where the water table
is artificially changed (e.g., drained or raised). This Wetlands Supplement extends this coverage also to include
wetlands created (e.g., constructed), or where emissions and removals from coastal wetlands are attributed to
specified human activities. The focus on human activities such as drainage or construction of aquaculture ponds
maintains the justification for the managed land proxy. In the case of seagrass meadows the guidance estimatesemissions and removals associated with changes linked to a specific human activity, rather than estimating
emissions and removals from that coastal wetland type as a whole. Application of the supplement will maintainconsistency with previous estimates so long as these activities can be recognised as subsets within the broader
definition of managed land. The application of new emission factors will not introduce inconsistency so long as
the historical time series is updated, consistent with long-standing IPCC advice.

136

9

UNFCCC Article 4 1 (a).
http://unfccc.int/files/essential_background/background_publications_htmlpdf/application/pdf/conveng.pdf

10

IPCC 2010, Revisiting the Use of Managed Land as a Proxy for Estimating National Anthropogenic Emissions andRemovals, eds: Eggleston H.S., Srivastava N., Tanabe K., Baasansuren J. Meeting Report, 5 -7 May, 2009, INPE, São José
dos Campos, Brazil, Pub. IGES, Japan 2010

DRAFT 2013 Wetlands Supplement

7

Overview

DO NOT CITE OR QUOTE

Final Draft

159

4 THE WETLANDS SUPPLEMENT AND THE
2006 IPCC GUIDELINES

160
161
162
163
164
165
166
167
168
169
170
171

The Wetlands Supplement follows the same approach to estimating emissions and removals as the 2006 IPCC
Guidelines. The 2006 IPCC Guidelines themselves are an evolutionary development starting from the 1996
IPCC Guidelines, 2000 IPCC Good Practice Guidance (GPG2000) and Good Practice Guidance – Land Use,
Land-use Change and Forestry (GPG-LULUCF). This evolutionary approach helps ensure continuity, andallows for the incorporation of experiences with the existing guidelines, new scientific information, and theresults of the UNFCCC inventory review process. An important structural change occurred in Volume 4, which
consolidated the guidance for LULUCF in GPG-LULUCF and the Agriculture sector in GPG2000 into a single
Agriculture, Forestry and Other Land Use (AFOLU) Volume. This Wetlands Supplement adds to the guidance
given in Volume 4 of the 2006 IPCC Guidelines, and provides updates where science has advanced, but does not
replace it. This Wetlands Supplement also adds to the guidance given in Volume 5 (Waste). Where the Wetlands
Supplement provides guidance that updates emission factors for land areas, categories, gases, and pools covered
directly by Volumes 4 and 5, the guidance in the Wetlands Supplement should take precedence.

172
173
174
175
176
177
178

The 2006 IPCC Guidelines retained the definition of good practice that was introduced with GPG2000. Thisdefinition has gained general acceptance amongst countries as the basis for inventory development. According tothis definition, national inventories of anthropogenic greenhouse gas emissions and removals consistent withgood practice are those, which contain neither over- nor under-estimates so far as can be judged, and in which
uncertainties are reduced as far as practicable. These requirements are intended to ensure that estimates ofemissions by sources and removals by sinks, even if uncertain, are bona fide estimates, in the sense of notcontaining any biases that could have been identified and eliminated.

179
180
181
182
183
184
185
186
187
188

The Wetlands Supplement, like the 2006 IPCC Guidelines, generally provides guidance, usually with decision
trees, on estimation methods at three levels of detail, from Tier 1 (the default method) to Tier 3 (the mostdetailed method; Chapter 1, Volume 1). The Tier 1 guidance generally consists of mathematical specification of
the methods and equations for estimating emissions/removals, information on emission factors or otherparameters to use in generating the estimates, and sources of activity data to estimate the overall level of net
emissions (emission by sources minus removals by sinks). Properly implemented, all tiers are intended toprovide unbiased estimates, and accuracy and precision are expected to improve from Tier 1 to Tier 3. The
provision of different tiers enables inventory compilers to use methods consistent with their resources and to
focus their efforts on those categories of emissions and removals that contribute most significantly to nationalemission totals and trends.

189
190
191
192
193

National circumstances include the availability of data and knowledge, and contribution made by the category tototal national emissions and removals and to their trend over time. The most important categories, in terms of
total national emissions and the trend, are called key categories11. The decision trees generally require Tier 2 orTier 3 methods for key categories. This approach to the use of different tiers allows limited resources to befocused on those areas of the inventory that contribute significantly to the overall total or trend in emissions.

194

Within Chapter 7 of the Wetlands Supplement advice is also provided on:

158

195

(i)

ensuring time series are consistent,

196

(ii)

estimation of uncertainties,

197
198

(iii)

guidance on quality assurance and quality control procedures to provide cross-checks during inventory
compilation,

199
200

(iv)

information to be documented to achieve transparent reporting, avoiding double-counting andomissions, to facilitate review and assessment of inventory estimates, and

201
202
203

(v)

reporting tables and worksheets for Tier 1 methods are provided as well as mapping between the
categories and guidance in the 2006 IPCC Guidelines and the changes to those introduced by the
Wetlands Supplement.

11

8

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

DRAFT 2013 Wetlands Supplement