60578 Paper number 121 E N V I R O N M E N T D E PA R T M E N T PA P E R S Marine Ecosystem Series Mitigating Climate Change through Restoration and Management of Coastal Wetlands and Near-shore Marine Ecosystems Challenges and Opportunities Stephen Crooks, Dorothée Herr, Jerker Tamelander, Dan Laffoley, and Justin Vandever March 2011 Sustainable Development Vice Presidency The World Bank environmenT deparTmenT Mitigating Climate Change through Restoration and Management of Coastal Wetlands and Near-shore Marine Ecosystems Challenges and Opportunities Stephen Crooks, Dorothée Herr, Jerker Tamelander, Dan Laffoley, and Justin Vandever March 2011 Papers in this series are not formal publications of the World Bank. They are circulated to encourage thought and discussion. The use and citation of this paper should take this into account. The views expressed are those of the authors and should not be attributed to the World Bank. This book is available on-line from the Environment Department of the World Bank at: www.worldbank.org/environment/publications © The International Bank for Reconstruction and Development/THE WORLD BANK 1818 H Street, N.W. Washington, D.C. 20433, U.S.A. Manufactured in the United States of America First published March 2011 The views expressed in this document are those of the authors and do not necessarily represent views of the World Bank, IUCN or ESA PWA. Reproduction of this publication for educational or other non-commercial purposes is authorized without prior written permission from the copyright holder provided the source is fully acknowledged. Reproduction of this publication for resale or other commercial purposes is prohibited without prior written permission of the copyright holder. Citation: Crooks, S., D. Herr, J. Tamelander, D. Laffoley, and J. Vandever. 2011. "Mitigating Climate Change through Restoration and Management of Coastal Wetlands and Near-shore Marine Ecosystems: Challenges and Opportunities." Environment Department Paper 121, World Bank, Washington, DC. Design: Jim Cantrell Cover photo: © Shutterstock LLC. Mangrove tree at low tide, Vilanculos Coastal Wildlife Sanctuary, Mozambique. Contents Preface vii executiveSummary 1 Chapter 1 Introduction 5 Chapter 2 GHG Dynamics in Coastal Wetlands and Marine Ecosystems 7 2.1 Carbon Sequestration by Coastal Wetlands and Near-Shore Marine Ecosystems 7 2.2 Carbon Losses from Degradation of Coastal Wetlands and Near-Shore Marine Ecosystems 8 2.3 Coastal Wetlands as Sources and Sinks of other Greenhouse Gases 9 Chapter 3 Avoiding Emissions and Increasing Carbon Sequestration 11 3.1 Avoidable Emissions 11 3.2 Creation and Enhancement of Coastal Carbon Stocks 13 3.3 Wetland Project Activities 15 3.4 Co-Benefits of Managing Coastal Wetlands and Marine Ecosystems for Climate Change Mitigation 16 Chapter 4 Status and Trends of Coastal Wetlands and Near-Shore Marine Ecosystems 19 4.1 Historical Extent of Coastal Wetland and Marine Ecosystems and Loss to Date 19 4.2 Drivers of Coastal Wetland and Marine Ecosystem Loss 20 4.3 Expected Future Loss and Degradation 20 Chapter 5 Policy Reform to Reduce Emissions and Enhance Coastal Carbon Stocks 21 5.1 Opportunities for Developing Countries 21 5.2 Opportunities for Developed Countries 23 5.3 Expanding UNFCCC Reporting Requirements 25 5.4 IPCC Guidance and Guidelines 26 5.5 Coordinated Action 28 Marine Ecosystem Series iii Mitigating Climate Change through Restoration and Management of Coastal Wetlands and Near-shore Marine Ecosystems Chapter 6 Conclusions and Recommendations 29 annexeS Annex 1: Current Coastal Carbon Activities 31 Annex 2: Derived Estimates of GHG Emissions from Coastal Carbon Sinks 33 referenceS 47 SourceScited 49 figureS Figure 1. Estimated CO2 Emissions from Drainage of Wetland Soils in Thirteen Large Deltas 12 Figure 2. Restoring a Vegetated Marsh Takes Time and Sediment 14 tableS Table 1. Summary of Potential GHG Reductions Due to Soil Building in Coastal Wetlands 2 Table 2. GHG Balance of Coastal Wetlands. Soil Burial of CO2 and CH4 Emissions 15 Table 3. Ecosystem Services of Coastal and Marine Ecosystems 17 iv Environment Department Papers Glossary AFOLU Agriculture, Forestry and Other Land Use CDM Clean Development Mechanism CH4 Methane CO2 Carbon Dioxide COP Conference of the Parties EbA Ecosystem-based Adaptation GHG Greenhouse gas GPG Good Practice Guidance IPCC Intergovernmental Panel on Climate Change KP Kyoto Protocol LULUCF Land use, land use change and forestry MRV Measuring, Reporting and Verifying N 2O Nitrous Oxide NAMA National Appropriate Mitigation Action NGO Non-governmental organization REDD Reduced Emissions from Deforestation and forest Degradation RMU Removal units SBSTA Subsidiary Body for Scientific and Technological Advice UNFCCC United Nations Framework Convention on Climate Change USGS U.S. Geological Survey Marine Ecosystem Series v Preface E cosystems in the land-ocean interface are gaining (Senior Fisheries Specialist, Agriculture and Rural increased attention for the carbon they store in Development Department) and Ian Noble (Lead biomass and especially sediments. This makes Climate Change Specialist, Environment Department). them potential sources of significant greenhouse ln light of rapidly evolving policy on the eligibility of gas (GHG) emissions if disturbed, but also valuable for REDD+ activities under the UNFCC, this activity was nature-based approaches to climate change mitigation. designed to inform policymakers and climate change practitioners on the capture and conservation of blue Scientific research into the exchange of GHGs between carbon in natural, coastal carbon sinks. The results the atmosphere and these ecosystems (known as flux) included a policy brief synthesizing the results of the has been underway for some time, but it was two study, which was circulated at the UNFCCC COP 16 reports published in 2009--The Management of in Cancun,5 and the detailed findings, presented here in Natural Coastal Carbon Sinks1 and Blue Carbon2--that this full technical report. brought this aspect to the attention of climate change practitioners. At the same time, the publication of The technical report, prepared by Stephen Crooks, the World Development Report 2010: Development Dorothée Herr, Jerker Tamelander, Dan Laffoley and and Climate Change,3 and Convenient Solutions to Justin Vandever, consolidates information from the an Inconvenient Truth,4 underscored the importance literature and provides analysis on the climate change of harnessing natural systems including wetlands, and mitigation potential of seagrasses and coastal wetlands, the carbon storage services they provide, in the fight to including coastal peats, tidal freshwater wetlands, salt reduce carbon emissions. marshes and mangroves (see Annex 2). The numbers in this full technical report have been adjusted since This report builds on these and other efforts to bring the synthesis note, produced while the study was in to light the important carbon sequestration potential progress, was released in Cancun. The calculations of of coastal wetlands, and the significant and largely emissions are ballpark, but reasonable, and represent unaccounted for GHG emissions resulting from the an order of magnitude range. They are meant to disturbance, drainage, and conversion of these natural stimulate additional and focused research, while coastal carbon sinks for agriculture, tourism and other raising awareness among the science, management and coastal development. policy communities of the dangers of ignoring these unaccounted for GHG sources and sinks. Conceived in discussions with the report authors, this study was commissioned and overseen by a Some initial steps are identified to integrate these team at the World Bank led by Marea Hatziolos fragile ecosystems into national and international (Senior Coastal and Marine Specialist, Environment climate change policy instruments and implementation Department), and peer reviewed by Kieran Kelleher activities, including market-based approaches. Marine Ecosystem Series vii Mitigating Climate Change through Restoration and Management of Coastal Wetlands and Near-shore Marine Ecosystems Although the study focuses primarily on coastal Both the synthesis and this full report are available at wetlands, it should be seen as part of a broader effort to www.iucn.org/marine and www.worldbank.org/icm quantify the contribution of coastal, near-shore marine and oceanic (open-ocean) carbon sinks to the global carbon budget and to build consideration of this into global climate change mitigation actions. viii Environment Department Papers Executive Summary C oastal wetlands and marine ecosystems hold and harvestable resources such as fish, as well as vast stores of carbon. Occupying only 2% of opportunities for recreation. seabed area, vegetated wetlands represent 50% of carbon transfer from oceans to sediments.6 Coastal wetlands and marine ecosystems This carbon can remain stored in buried sediments sequester Carbon for millennia. Loss of coastal wetlands and marine ecosystems such as peatlands, forested tidal wetlands, Coastal wetlands and marine ecosystems sequester tidal freshwater wetlands, salt marshes, mangroves and carbon within standing biomass, but even more seagrass beds leads to decreased carbon sequestration within soils. In many cases these peat-like soils have and can also lead to emissions of large amounts of CO2 been continuously building for over 5,000 years, or directly to the atmosphere. Largescale emissions from longer. Wetlands in salinea environments have the ecosystem degradation and habitat conversion of these added advantage of emitting negligible quantities of wetlands are ongoing but currently not accounted for in methane, a powerful greenhouse gas, whereas methane national greenhouse gas inventories, nor are these being production in freshwater systems partially or wholly mitigated to any degree. negates short-term carbon sequestration benefits (see Table 1). However, over multi-century time scales all The current climate policy regime contains few coastal wetlands are net GHG sinks. incentives for restoration or disincentives to drain or degrade coastal wetlands. Yet, carbon dioxide emissions Drainage of Coastal wetlands releases from drained coastal wetlands are sufficiently large to large amounts of stored Carbon warrant inclusion in carbon accounting and emission inventories, and in amendments of national and Human-caused drainage of coastal wetlands releases international policy frameworks to reduce emissions carbon from soils, turning them into a strong net from the loss of these ecosystems. Further work is source of GHG emissions, irrespective of their GHG needed to quantify the magnitude of emissions from balance in the natural state. Soils vary in carbon near-shore marine ecosystems such as seagrass beds. It is, content across the landscape but a "typical" coastal however, clear that improved management of these wetland soil releases 0.1 MtCO2 per square kilometre systems would slow or reverse ongoing loss of carbon for every depth meter of soil lost (Annex 2b), though sequestration capacity. Sustainable management of coastal wetlands and marine ecosystems also offer a wide range of co-benefits, including shoreline a Salinities greater than ½ that of sea water. b Data emerging from the analysis outlined in Annex 2 of this protection, nutrient cycling, water quality maintenance, report has been developed with the intent of subsequent scientific flood control, habitat for birds, other wildlife peer review. Marine Ecosystem Series 1 Mitigating Climate Change through Restoration and Management of Coastal Wetlands and Near-shore Marine Ecosystems Table 1. Summary of potential GHG reductions due to Soil building in coastal wetlands7 Wetland Type Carbon Sequestration Methane Production Net GHG Sink Mudflat (saline) Low Very Low Low to Medium Salt Marsh High Very Low High Freshwater Tidal Marsh Very High High to Very High Neutral or variable Estuarine Forest High Low High Mangrove High Low to High* Low to High* Sea grass High Low High *salinity dependent with a wide range. Averaged over a 50-year period this management of Coastal wetlands and equates to 2,000 tCO2 km-2 yr-1, though rates of loss are marine ecosystems Can mitigate particularly high in the first decade of wetland drainage. GHG emissions Coastal wetlands are under direct and increasing Coastal wetlands are being rapidly converted to threat from land use change pressures,9 from indirect agriculture and other land-uses around the world, leading impacts of upstream disruption to sediment supply, and to significant emissions. In the Sacramento ­ San Joaquin from development pressures and rising sea level at the Delta, California, drainage of 1,800 km2 of wetlands has coast. Altered sediment supply and delta subsidence released some 0.9 GtCO2 (Giga tons, or billion tons of exacerbate sea level rise, with local rates commonly carbon dioxide), a mass of about one quarter of the total twice, and in some locations as much as 10 times, above ground pool of carbon in Californian forests, over global rates.10 Large areas of coastal wetland have been the last century. This carbon was sequestered over four drained and converted to other uses. thousand years but released in just over 100 years. Each year, between 5 and 7.5 million tons of CO2 continue In the last 25 years alone, between 1980 and 2005, to be released from this Delta, equivalent to 1­1.5% of about 20% of the total area of mangroves was lost.11 California's annual GHG emissions. Other large deltas Seagrass beds have declined by 29% since the 19th estimated to have each released over one half a Gt CO2 century, with an upsurge in the recent decades.12 Salt due to land-use change are: the Changjiang (3.4 GtCO2); marshes and freshwater tidal marshes have lost more the Mekong Delta (3.3 GtCO2); the Po (1.5 GtCO2); the than 50% of their historical global coverage, with the Nile (0.8 GtCO2); the Wash-Humber, eastern UK (1.1 current rate of loss estimated at 1­2% per year. GtCO2); and the Indus (0.6 GtCO2). Centuries to millennia of accumulated carbon is Between 1980 and 2005, 35,000 km2 of mangroves released in a few decades when coastal wetlands are were cleared and drained.8 We estimate that this area drained or otherwise lost. For organic-rich soils the of wetland alone will continue to release 0.07 GtCO2 process of soil deflation may continue for centuries every year. Loss of the remaining 152,308 km2 of until all resources are depleted. The most effective mangroves would release 0.3 GtCO2 over the same way to maintain wetland carbon pools and prevent time; as well as result in incalculable losses in other emissions to the atmosphere is avoiding conversion ecosystem processes and services. Remaining coastal and drainage through protection and sustainable wetlands with peat-rich soils, which release higher management. Restoration of degraded ecosystems has a than average amounts of carbon per unit area, are twofold benefit: reducing ongoing losses and rebuilding being rapidly converted for oil palm plantations and carbon stores. However, sequestration rates during aquaculture in parts of Southeast Asia. restoration are, in most cases, lower than rates at which 2 Environment Department Papers Summary carbon is lost when drained, reducing the mitigation and assessing social and economic impacts as well as potential in the short-term, but not in the long-term. environmental and social safeguard risks. Further efforts are needed to increase the number and efficiency of restoration activities. Current IPCC guidelines for accounting GHG emissions by sources and removals by sinks could easily be expanded to also encompass, for example, Opportunities to strengthen nature-based rewetting and draining of coastal wetlands. National mitigation in Coastal areas climate change mitigation reporting procedures should There is now adequate knowledge to take policy as well be amended accordingly to also include action on as practical actions towards the inclusion of emissions the restoration and enhancement of coastal wetlands from sources and removals by sinks in coastal areas in and nearshore marine ecosystems. However, further GHG accounts. Stronger incentives to better manage, research is necessary for development of additional along with disincentives to drain or otherwise damage, or supplementary methodologies covering other these ecosystems need to be created. coastal and marine ecosystem types and management activities, including, e.g. baseline data, monitoring Conservation and management actions focusing on and verification approaches, as well as testing and coastal wetlands and near-shore marine ecosystems verification of methods through a network of pilot can already be included in developing countries' projects. National Appropriate Mitigation Actions (NAMAs). While financial support for mangrove conservation Land Use, Land Use Change and Forestry (LULUCF), and restoration for mitigation purposes can be as defined through UNFCCC, should also encompass obtained through inclusion of these activities in rewetting and drainage of coastal wetlands in a second national REDD+ strategies, policies and measures, commitment period of the Kyoto Protocol. This development of an additional financing mechanism would enable additional, coastal LULUCF activities for coastal wetlands and near-shore marine ecosystems under the Clean Development Mechanism (CDM). that provides financial incentives for soil-based carbon Harmonizing definitions and categories of activities storage and sequestration would be beneficial. However, related to ecological restoration and management of further detailed analysis of the potential for coastal and coastal wetlands and marine ecosystems under IPCC near-shore nature-based mitigation is needed, including and UNFCCC will support these actions. quantifying the carbon balance in these habitats, Marine Ecosystem Series 3 1 Introduction T here is overwhelming consensus amongst climate based mitigation--is not a new concept. The United scientists that the Earth's warming in recent Nation Framework Convention on Climate Change decades has been caused primarily by human (UNFCCC) as well as the Kyoto Protocol make clear activities that have increased the amount of reference to reducing emissions by sources and removals greenhouse gases (GHGs) in the atmosphere.13 To by sinks in natural systems. Development of the mitigate the most serious impacts of climate change REDD+c scheme, as agreed at UNFCCC COP16 in a range of different strategies to lower carbon dioxide Cancun 2010, has provided a mechanism for financing (CO2) concentrations in the atmosphere are required. forest restoration and conservation and management of forests, leading to enhancement of carbon stocks and Healthy coastal wetlands such as coastal peats, tidal avoided emissions. freshwater wetlands, salt marshes, mangroves and seagrass beds store vast amounts of organic carbon in Progress with respect to the inclusion of coastal wetland sediments and biomass. This carbon is released as CO2 and seagrass bed management and restoration activities into the atmosphere when ecosystems are damaged into national and international climate regimes or lost. Ongoing coastal ecosystem conversion and has been held back by a lack of detailed knowledge degradation, in many places exceeding the rates about their potential for climate change mitigation, of ecosystem loss on land, lead to continuous and and absence of applicable carbon accounting significant emissions. methodologies. This report helps address some of these gaps and uncertainties, while pointing to the need for However, while these emissions could be reduced more quantitative analysis of carbon balance in these through conservation and sustainable management, and systems in temperate and tropical waters, in order restoration of degraded areas could promote sequestration to move towards more comprehensive accounting of of additional CO2 from the atmosphere, the potential reduction of emissions by sources and removals by sinks of coastal wetlands and seagrass beds for climate in all natural systems within the climate change regime change mitigation has not yet been fully explored. and enable better-informed mitigation actions. Consequently, the CO2 emissions and sequestration associated with coastal wetlands and seagrass beds are Building on outcomes and recommendations from currently neither accounted for in national greenhouse various coastal carbon activities (see Annex 1), this gas (GHG) inventories, nor do incentives for restoration report explains the GHG dynamics of coastal wetlands or disincentives to drain or damage these systems exist in international policy frameworks. c Reducing Emissions from Deforestation and Forest Degradation Working with nature to reduce GHG emissions and and the role of conservation, sustainable management of forests to enhance carbon sequestration--or ecosystem- and enhancement of forest carbon stocks in developing countries. Marine Ecosystem Series 5 Mitigating Climate Change through Restoration and Management of Coastal Wetlands and Near-shore Marine Ecosystems and marine ecosystems (Chapter 2). The importance of policy opportunities under ongoing UNFCCC of coastal wetland and near-shore marine ecosystem negotiations and through revision of Intergovernmental carbon pools for climate change mitigation are Panel on Climate Change (IPCC) carbon accounting described in Chapter 3, with a brief overview of the methodologies and eligible mitigation activities for status of these systems, including drivers of change developing as well as developed countries. The main and implications of degradation of carbon pools, recommendations for action are summarized in provided in Chapter 4. Chapter 5 gives an overview Chapter 6. 6 Environment Department Papers GHG Dynamics in Coastal 2 Wetlands and Marine Ecosystems C oastal areas receive large inputs of organic matter All coastal wetlands are long term net sinks for and nutrients from land through sediment atmospheric CO2 through production of standing runoff via rivers and from ocean upwelling biomass and burial of primarily root and rhizome and currents. This makes coastal ecosystems organic matter in sediment. The amount of carbon among the most biologically productive areas of the stored can be variable depending upon wetland type planet.14 The high productivity of coastal wetlands and landscape setting. By and large, the productivity of and seagrass beds supports significant sequestration of vegetation, be it temperate or tropical, increases from carbon in sediment, below ground biomass and within the saline end of estuaries and deltas to the freshwater surface and waterborne plants and animals. Notably, head of these systems. As such, we commonly find the potential for continuous deposition of carbon in greater carbon accumulation within freshwater sediments that can accrete over millennia--unlike vegetation and soils than at the saline margin. e.g. forests, which tend to reach a steady state within Nevertheless, carbon sequestration across the salinity decades to a century--makes these coastal ecosystems transition is significant. valuable tools in mitigation. Further, conserving and restoring coastal wetlands and seagrass beds can also The preservation of soil carbon is a result of the regular support adaptation measures. This chapter summarizes tidal flooding of wetland, fostering saturated soil mechanisms by which coastal wetlands and seagrass conditions, where under conditions of low oxygen beds sequester carbon and support the regulation of availability, decay rates of soil organic matter and global GHG levels. release of carbon dioxide are greatly reduced. Gradual additions to the carbon pool are made as the soil surface continues to build with rising sea level, and organic 2.1 Carbon sequestration by Coastal material becomes progressively buried beneath saturated wetlands and near-shore marine soils. Rates of carbon release through microbial ecosystems decomposition are slow unless the wetland is disturbed. Coastal wetlands consist of a mosaic of habitat In many coastal settings, accumulations of organic types that include mudflats, salt marshes, brackish bearing soils have built up dating back to the mid marshes, mangroves, freshwater tidal wetlands, Holocene (around five thousand years old). and high intertidal forested and scrub wetlands, and coastal peat lands. Offshore coastal wetlands Deltas built by enormous accumulations of mineral give way to expansive areas of seagrasses, kelp beds sediment, sustain extensive areas of vegetated wetlands. and unvegetated seabed. These ecosystems reflect a These deltas consolidate under their own weight, progressive transition from the land drained by rivers, and through the slow expulsion of water the land through coastal flood lands to the open continental subsides. Flooding waters bring replenishing sediments shelf and the ocean beyond. and allow wetlands to keep pace with rising relative Marine Ecosystem Series 7 Mitigating Climate Change through Restoration and Management of Coastal Wetlands and Near-shore Marine Ecosystems sea level,d burying carbon in the process. Typically, In areas where rates of mineral sediment supply are undisturbed deltas are resilient to high rates of sea high, soil carbon contents may represent less than 5% level rise because of the high rates of sediment supply. of soil dry weight, reflecting dilution with non-organic Expansive and contiguous tidal wetlands are found material.21,22,23,24 However, in inner reaches of temperate e.g. in the Amazon, the coast of Venezuela, Ganges- and tropical deltas, estuaries and lagoons, where Brahmaputra, Alaska, and Louisiana. In many regions mineral sedimentation is low, organic rich soils and of the world delta wetlands have been heavily diked peats may form carbon contents of 30%­50% or more, and drained, particularly in Northern Europe and the comparable with terrestrial peat soils.25,26,27,28,29,30,31,32,33,34 United States, and recently throughout Asia, mainly in These carbon rich soils may be many, several to 10 Southeast Asia. or more, meters deep and hold up to 65,000 tons C (238,000 tC02) per km2 for every meter depth of soil.35 Extensive coastal wetlands also build up along coasts and on low-lying islands away from The global distribution of coastal wetland peaty soils terrestrial sources of sediment. In locations such as is poorly mapped, but likely to be widespread and the island coasts in the Gulf of Mexico, Micronesia extensive. Soil descriptions from large coastal deltas and Indonesia deep sequences of organic rich such as the Orinoco36 and the Mekong37,38 report coastal peats have accumulated, largely devoid of organic rich soils covering about 50% of the area. In mineral sediment, through the gradual accretion of the freshwater tidal Sacramento-San Joaquin Delta vegetation under conditions of relatively slow rates peat soils represented almost the full extent of the once of sea level rise. These systems store very dense 1,800 km2 delta to a depth of around 10 meters.39,40 deposits of soil carbon. Similarly, organic rich soils are found beneath mangroves in Australia, South East Asia,41 Mexico42 and The proximity of many mangroves, sea grasses and also Belize.43 coral reefs is recognized to provide particularly high biodiversity and productivity. This is in part because of 2.2 Carbon losses from Degradation of the diversity of habitat but also because of the complex Coastal wetlands and near-shore interactions of food webs and carbon flows between marine ecosystems these ecosystems (e.g. Nagelkerken et al., 200015). Seagrass meadows are excluded in areas of high Processes that destroy vegetation in coastal wetlands sediment yield, which lowers light attenuation into and near-shore marine ecosystems effectively halt a the water column and smothers vegetation. Where significant component of ongoing carbon sequestration. present, certain seagrass beds sequester carbon within Drainage, the artificial lowering of the soil water soils in a manner very similar to intertidal wetlands, table, allows oxygen to enter soils, which then release producing deposits of organic rich sediments. soil carbon to the atmosphere in the form of carbon Published data on soil carbon deposition of seagrasses dioxide. Drainage of coastal wetlands and conversion to is limited both geographically and taxonomically. agricultural or other land uses therefore not only halts However, thick beds of organic matter within ongoing carbon sequestration but releases carbon stocks gradually accumulating sediments are commonly that built up over many centuries, and in peat rich associated with the seagrass species Posidonia oceanica, systems, many millennia.44,45 and a limited number of studies document that sediments below seagrass beds or mattes host a carbon content of up to 40%, reflecting millennia of carbon d Relative sea level rise--the combination of global sea level rise accumulation.16,17,18,19,20 and the impacts of local land movement. 8 Environment Department Papers GhG Dynamics in Coastal Wetlands and Marine Ecosystems The rate at which carbon is released to the atmosphere 2.3 Coastal wetlands as sources and sinks with wetland drainage is anticipated to be most rapid of other Greenhouse Gases during the years immediately following wetland conversion and then to subside with time. This process Some coastal wetlands emit methane (CH), a is however poorly documented. Lessons can be drawn greenhouse gas 25 times more potent that CO2. The from the progressive drainage of terrestrial freshwater formation of methane occurs in low salinity or non- wetlands in northeast China. By examining the carbon saline environments and requires strictly anaerobic content on former wetland soils of different ages conditions. Methane production is generally intense in researchers determined that 60% of near surface carbon brackish and freshwater tidal flats and marshes because was lost within the first 10 years after drainage.46 of the high organic matter content of the soils at anoxic depths. Methane production decreases by two orders In settings where wetland soils consist mostly of mineral of magnitude, to negligible levels, as salinity increases matter the rate of carbon loss stabilizes over time.47,48 to roughly ½ that of seawater because of the impact of By contrast, in settings where organic matter makes up sulphate on biogeochemical processes.59 the bulk of the sediment soil, loss can be continuous, leading to deep depressions in the landscape due to In many wetlands some of the methane produced in compression following drainage. With drainage, five subsurface soils is oxidized and denatured as it diffuses components to subsidence are recognized:49 to the atmosphere through the oxygenated soil surface.60 1) shrinkage due to desiccation; 2) consolidation with In freshwater and brackish marshes (vegetated by tule, water loss; 3) wind and water erosion; 4) burning; common reed, and sedge) this pathway is short cut by a 5) aerobic oxidation of soil carbon. Of these processes route through deep soils and by air passages in the plant aerobic oxidation has been found to be the most to the atmosphere.61 Forested wetlands that are flooded significant cause of subsidence in organic soils.50,51 for only parts of the year produce less CH4 than fully tidal marshes because of the periods of prolonged drying Loss of carbon-rich soils has been documented at rates and exposure to the atmosphere during lowered water of between less than 1 cm yr-1 to more than 10 cm yr-1. table. Such systems may even be net sinks for CH4. In the Sacramento ­ San Joaquin Delta, a basin of more than 3 billion m3 (3 km3), up to 10 meters deep, has Another greenhouse gas of concern in coastal been created through the drainage and oxidation of environments is nitrous oxide (N2O). N2O is mainly peat soils. Over the past 100 years 1­3 cm of surface formed as a by-product during nitrification (the soils have been lost each year, equating to a continuous breakdown of ammonia to nitrate and nitrite) and soil carbon loss of approximately 20 tons C ha-1 yr-1 as an intermediate during denitrification (conversion (7,300 tCO2 km-2 yr-1) and a total emission of around of nitrate to nitrous oxide and nitrogen).62 Both 1 GtCO2.52,53,54 In the Po Delta, Italy, drained peat soils nitrification and denitrification are microbial have subsided by 4 meters since 1930.55 In The Wash, processes that can happen in the water column and in U.K., peat soils are lost at a rate of 1­3 cm per year.56 sediments, mediated by bacteria living in low oxygen In Florida, drained organic soils continuously subsided environments. Ammonia and nitrate are natural by 2.5 cm yr-1 between 1925 and 1978.57 In Malaysia, constituents in estuarine waters but are now found at drained organic rich soils subsided at a rate of 12 cm heightened levels in wetlands due to agriculture and yr-1 between 1960 and 1974, falling to 6.4 cm yr-1 over other anthropogenic sources such as air pollution. the following 14 years and 2 cm yr-1 thereafter,58 hinting at the heightened rates of carbon loss that occur in the While estuaries overall are very effective systems for years immediately after organic rich soils are drained. the recycling of nitrogen, the capacity of estuaries to Marine Ecosystem Series 9 Mitigating Climate Change through Restoration and Management of Coastal Wetlands and Near-shore Marine Ecosystems do so has been degraded by the loss of tidal wetlands.63 Overall, tidal wetlands are a net sink for carbon even Denitrification is not confined to intertidal sediment though they release a percentage of that as CO2 to the but continues in organic bearing continental shelf atmosphere or in particulate or dissolved form to the sediments beyond the estuary, and in the anoxic estuary. In brackish and freshwater tidal systems, large waters of nutrient-loading induced dead zones. As a amounts of CH4 are released from anoxic soil, which, consequence, while restored wetlands do contribute from a GHG mitigation perspective, may exceed to the production of small amounts of N2O, this their carbon sequestration value. Tidal wetlands also compound would be produced elsewhere in the contribute a small amount of N2O production, but this estuarine or on the adjacent continental shelf, even is a function of nitrogen pollution in coastal areas, and without the presence of the wetland. As a result, the these emissions would most likely occur regardless of presence of the N2O precursor compounds and their the presence of the wetland. associated emissions would likely remain unchanged regardless of whether the wetlands are there or not. 10 Environment Department Papers Avoiding Emissions and Increasing 3 Carbon Sequestration T here are two primary mechanisms to reduce sediment supply) as well as those in relatively pristine greenhouse gas emissions in a landscape with condition. ongoing loss of coastal wetlands and near-shore marine ecosystems: 1) conserving historically By synthesizing studies that describe the carbon content sequestered pools of carbon; and 2) restoring and of coastal wetland soils, and calculating the volume of rebuilding degraded carbon pools. The rate at which soil loss (derived using global elevation SRTMe data), carbon is lost from disturbed coastal wetlands is we can provide an approximate estimate of the CO2 typically much greater than the rate at which it can be released since the time of wetland drainage. Soils vary restored. Therefore, when planning to manage carbon considerably in coastal settings but to simplify the stocks it is more effective to prevent carbon-bearing soils analysis we assume two soil types: organic-bearing soils from being disturbed than to begin a process of restoration. and organic-poor (mineral) soils with a carbon content However, given the dramatic decline in coastal wetland of 20% and 6%, respectively. and near-shore marine ecosystem extent over recent decades (see Chapter 4), restoration activities are Within these few deltas and estuaries we identify several critically needed to rebuild carbon sinks and restore systems to have likely lost more than 1 billion tons of coastal and near-shore marine ecosystem health. CO2. Deltas with large emissions include the Indus Delta (0.6 GtCO2); The Wash-Humber (1.1 GtCO2); the Mekong Delta; (3.3 GtCO2), the Nile (0.8 GtCO2); 3.1 avoidable emissions the Po (1.5 GtCO2); the Changjiang (3.4 GtCO2); and Preventing drainage of coastal wetlands is an effective the Sacramento ­ San Joaquin Delta (>0.9 GtCO2) measure to maintain carbon in soils and CO2 out of (Figure 1). We estimate the CO2 loss from these delta global circulation. But how effective? To date, no global soils, per meter depth, at 0.1 Mt / km2.f and few local estimates have been made of the CO2 flux that occurs with drainage of coastal wetland soils, and Similarly, based upon a reasonable assumption of 2­4 CO2 emissions are not accounted for in national and cm of soil being lost each year we estimate that the international GHG emissions inventories. drainage of 35,000 km2 of mangroves between 1980 and 200564 to release 0.16 MtCO2 km-2 within the In Annex 2 of this report we describe an analysis to first 50 years after land-use conversion, and continuing estimate the CO2 released from 15 case study deltas thereafter. Loss of remaining mangrove areas would and estuaries around the world. These systems reflect a representative range of large deltas and estuaries in tropical (mangrove) and temperate (saltmarsh and e http://www2.jpl.nasa.gov/srtm/ f The range on these estimates is sensitive to assumptions and freshwater tidal) settings, and include those threatened varies by ecosystem type and geographic setting in the estimated by human impacts (direct drainage or disrupted range of 0.025 to 0.38 MtCO2/m depth/km2. Marine Ecosystem Series 11 Mitigating Climate Change through Restoration and Management of Coastal Wetlands and Near-shore Marine Ecosystems Figure 1. Estimated cO2 Emissions from drainage of wetland Soils in Thirteen large deltas This dataset is a small but representative case study subset of global coastal systems, including both temperate and tropical deltas. Almost all coastal systems are subject to wetland conversion and drainage, releasing CO2. Included with the emissions estimates is a description of delta vulnerability to potential flooding associated with present day sea level rise and reduced sediment supply from rivers (derived from Syvitiski et al., 2009). Technical description of analysis is provided in Annex 2. Source: 2001 NASA MODIS 1km satellite images (Obtained from ESRI Data & Maps DVD, ArcGIS 9.3) ©ESA PWA release 24,000 MtCO2 within a few decades of along the northeast coast of South America (Venezuela drainage, and would further continue over time. & the Guyanas).65 and references therein If this estimated area approximates the distribution of drained organic soils How much CO2 has been released by the drainage around the world, and each square kilometre of land is of other wetlands? This is difficult to say. Research emitting 2,000 tCO2 per year, then globally, historically is required to document the full extent of drained drained coastal wetlands are releasing around 0.35 organic rich wetland soils in coastal settings. To gain a GtCO2 each year. sense of this potential area, a broader indication may be inferred from the mapped widespread occurrence The above estimates of emissions give us an indication of acid sulphide soils associated with agriculture in of the potential implications of wetland conversion. coastal lowlands. The formation of such soils is specific There are approximately 350,000 km2 of coastal to former saline (marine) sediments and requires mangroves and salt marshes remaining, drainage of organic matter bearing soils. Over 170,000 km2 of acid which could emit an additional 0.70 GtCO2 per year sulphide soils have been mapped globally, particularly through soil carbon loss. from deltaic settings, with major areas occurring in SE Asia (Indonesia, Thailand, Vietnam & Malaysia), Unlike coastal wetlands, the fate of carbon held in Australia, India, Bangladesh, West Africa (Senegal, the seagrass beds disturbed by activities such as dredging Gambia, Guinea Bissau, Sierra Leone & Liberia) and and trawling is unknown. Further analysis is required 12 Environment Department Papers Avoiding Emissions and Increasing Carbon Sequestration to determine whether these organic sediments are restoration of coastal wetlands occurs on lands where redeposited or a fraction oxidized upon redistribution. vegetated wetlands once existed, but are now behind levees. Diking and drainage of coastal wetlands results Remaining coastal wetlands and marine ecosystems are in land subsidence, and as such these lands often under particular pressure in Southeast Asia, (notably require raising, usually through natural sedimentation. Indonesia and Thailand, Borneo and Sumatra), India, The time interval until the mudflat builds up to Bangladesh and West Africa. The world largest tracts vegetation colonization elevations reflects the depth of of remaining unbroken wetlands can be found in subsidence, the availability and rate of accumulation of Northern Brazil (6,516 km2), the Sundarbans (6,502 sediment (Figure 2). km2), Southern Papua (5,345 km2), the West African mangrove coast (7,887 km2), the Niger Delta (6,642 The capacity of coastal wetlands to accumulate carbon km2) and the Orinoco and Gulf of Paria (2,799 km2).66 has been the focus of several review studies. Gathering together data from 154 marshes, mainly from the United States but also from overseas, Chmura et al. 3.2 Creation and enhancement of Coastal (2003) estimated that salt marshes and mangroves Carbon stocks accumulated, on average 150­250 tons C km-2 yr-1 Restoration of degraded coastal wetland and near-shore (550­917 g CO2e m-2 yr-1), though the range varied marine ecosystem carbon pools offer potential to reverse over an order of magnitude.68 In a similar summary GHG emissions, enhance existing carbon stocks and assessment, Duarte et al., (2005) reviewed the restore co-benefits. There is a time lag following the contribution of vegetated and unvegetated coastal initiation of restoration and the time at which carbon wetlands to carbon sinks in coastal areas and estimated sequestration in the wetland matches natural reference that salt marshes, mangroves and sea grass areas store sites. This is because restoration of wetland requires 151, 139 and 83 tons C km-2 yr-1 (554, 510, 304 establishing a surface elevation at which plants will tCO2e km-2 yr-1), respectively; while unvegetated areas colonize and contribute to soil carbon building processes. of estuaries (mudflats) and the open continental shelf This critical colonization elevation varies by ecosystem. accumulate 45 and 17 tons C km-2 yr-1 (165 and 62 tCO2e km-2 yr-1) (Table 2).69 Seagrasses are found in low intertidal and subtidal environments and will reestablish if water quality Carbon accumulation estimates range over two orders conditions are appropriate and human disturbance of magnitude, which reflect interactions between is limited. Mangroves and salt marsh colonize at climate, vegetation type, salinity (a primary control elevations above mean tide level (specific elevations of vegetation type), and soil type (capacity to store dependent upon species). Freshwater reeds may carbon in soils). Moving from the saline environment grow down to or just below the low tide elevation. to freshwater tidal wetlands there is potential to Once healthy vegetation has reestablished carbon accumulate over 500 tons C m-2 yr-1 (1,833 tCO2e km-2 sequestration rates compare favourably with natural yr-1), perhaps over 1000 tC km-2 yr-1 (3,667 tCO2e km-2 reference conditions.67 yr-1) on long-term restoration projects.71,72 It appears from the literature that organic matter accumulation The process of coastal wetland restoration is well is limited by salinity and has a maximum threshold;73 understood and documented within the scientific freshwater wetlands are able to accrete at rates greater literature, with numerous case studies that extend back than sea level rise, until an elevation threshold relative over several decades, and in the case of unintentional to water elevations is reached. Vegetation planting and restoration over more than a century. Typically, simple water management can potentially quite rapidly Marine Ecosystem Series 13 Mitigating Climate Change through Restoration and Management of Coastal Wetlands and Near-shore Marine Ecosystems Figure 2. restoring a vegetated marsh Takes Time and Sediment The time taken to restore a vegetated tidal wetland depends upon the degree to which the diked wetland has subsided due to drainage and the availability of mineral sediment to rebuilt mudflats to marsh colonization elevations. An exception to this model is areas where organic soils can be rebuilt using fast growing freshwater reeds. In all cases, with rising sea level the time to restore wetlands increases. A. Sedimentation curves for range of initial mudflat bed elevations 8 7 Elevation (ft, NAVD) 6 5 4 3 2 1 0 ­1 ­2 0 10 20 30 40 50 Time (years) ­1.3 ft 0.7 ft 2.7 ft 4.7 ft MHHW Approximate elevation of salt marsh vegetation colonization B. Sedimentation curves for range of suspended sediment concentrations 8 Elevation (ft, NAVD) 6 4 2 0 ­2 ­4 0 5 10 15 20 25 30 35 40 45 50 Time (years) 350 mg/L 300 mg/L 200 mg/L 100 mg/L 50 mg/L MHHW Approximate elevation of salt marsh vegetation colonization Notes: (a) Ambient sediment concentration of 250 mg/L (a) and (b) Mean monthly tide from Petaluma River Entrance rate of sea level rise = 5.67 mm/yr. Tide range approximately 6.1 ft, MLLW = 0.0 ft NAVD, MHHW = 6.1 ft NAVD. Source: MARSH98 Sedimentation Model, ESA PWA. restore reeds swamps or freshwater tidal marshes on Managed freshwater wetlands (built on subsided former subsided land. For this reason restoring freshwater marsh areas) have through water management practices wetlands, during the interval of enhanced soil building, demonstrated the capacity to raise marsh surface at rates potentially offers higher capacity to store carbon far in excess of rates of sea level rise. Experimentation than restoring saline wetlands, although methane by the USGS in the Sacramento ­ San Joaquin Delta emissions will need to be accounted for. However, has demonstrated that water management activities can coastal wetlands carbon sinks cannot be cost-effectively halt ongoing carbon loss in formerly drained organic restored on managed systems behind levees, with the soils as well as help rebuild soils and their carbon stock. possible exception of rebuilding subsided freshwater Now in its 13th year, the USGS study has documented tidal marshes by growing reed beds. marsh surface accumulation of over 4 cm yr-1.74,75 With 14 Environment Department Papers Avoiding Emissions and Increasing Carbon Sequestration Table 2. GHG balance of coastal wetlands. Soil burial of cO2 and cH4 Emissions70 Wetland Type Carbon Sequestration Potential Methane Production Potential Net Balance tC km­2 yr­1 tCO2e km­2 yr­1 tCH4 km­2 yr­1 tCO2e km­2 yr­1 Mudflat (saline) Low Low Low Low Low (< 50) (183) (< 2) (< 50) Salt Marsh High High Low Low High (50­250) (183­917) (< 2) (< 50) Freshwater Tidal Marsh Very High Very High High-Very High High-Very High Unclear ­ neutral* (500­1,000) (1,833­3,667) (40­100+) (1,000­2,500+) Estuarine Forest High High Low Low High (100­250) (367­917) (< 10) (< 10, 250) Mangroves High High Low ­ High Low ­ High Depends on salinity (50­450) (184­917) Sea grass High High Low (< 2, <50) High (45­190), (165­697) Note: 1gC 3.67 gCO2e; 1gCH4 25 gCO2e * Too few studies to draw firm conclusions. Potentially CH4 emissions from freshwater tidal wetlands may partially or fully negate carbon sequestration within soils. an average soil carbon content of about 0.2 gC cm-3 tidal freshwater to marine. Like terrestrial wetland they such accretion rates would equate to an accumulation contribute to the formation of soil types that, depending of about 1,000 tons C km-2 yr-1 (3,667 tCO2e km-2 upon landscape locations, form low carbon to high carbon yr-1). Methane emissions during this process reduce the peaty soils. Moreover, the carbon stored within mangrove net GHG sequestration to the range of 1,000­2,000 tree standing biomass is, like other forest types, significant. tCO2e km-2 yr-1.76 Projects rebuilding carbon soils in An unquantified parameter in the carbon equation is the subsided lands normally take several decades, hence dead root material left behind when trees die. allowing for prolonged carbon sequestration on a single project area. Moreover, because carbon losses 3.3 wetland project activities from agricultural soils on former wetlands can be considerable, in the case of Sacramento-San Joaquin The science of restoring coastal wetlands and marine of the order of 40 tCO2e ha-1 or higher,77 it will be ecosystems has advanced considerably over the past possible to credit projects with both an avoided loss 30 years.80,81 Increasingly projects of over 1,000 ha component and a restoration component. or 5,000 ha are being planned and implemented. Some restoration projects are relatively easy, requiring Brackish wetlands are an intermediary between saline low cost methods and approaches. Other projects and freshwater wetlands and their carbon storage may be complicated by the factors such as the need potential is likely to fall somewhere in the range to accommodate management of adjacent lands, between freshwater and saline wetlands.78 Little work competing uses or similar constraints. has been carried out to characterize the soil carbon storage potential of estuarine scrub / shrub and forested The history of carbon cycle management shows that wetlands, once common features of the landscape at biological carbon sequestration is closely tied to ecosystem the margin of estuaries, though one estimate by Yu et management decisions. Decisions about future biological al. (2006) suggests the storage potential could be in carbon sequestration will require careful considerations comparable range to salt marsh.79 of priorities and trade-offs.82,83 Restoring wetlands would in many instances involve change in land use, where the Mangroves are trees that grow at intertidal elevations costs and benefits would have to be assessed in each case. and are found across the full salinity transition from Restoring drained wetlands presently used for agriculture, Marine Ecosystem Series 15 Mitigating Climate Change through Restoration and Management of Coastal Wetlands and Near-shore Marine Ecosystems for example, could lead to reduction of food production. a persistent resilient system integrated within the It is clear, however, that there are significant areas of landscape. Restoration activities mean landscape- drained wetlands where restoration would lead to an scale restoration that significantly increases and increase in net benefits, in some cases even if the climate maintains carbon stocks and results in healthy benefits would not be counted. resilient ecosystems that provide the multiple goods and services people need, maintain biodiver- Appropriate planning greatly enhances the potential sity and enhance ecological integrity. success of a project. Unexpected failure of projects · Wetland carbon enhancement ­ Increasing one or occurs primarily through inadequate planning (e.g. more of the functions performed by an existing wet- planting vegetation without understanding why land beyond what currently or previously exists/ed in vegetation is not already present or has died, or the wetland. This is pertinent to managed wetlands artificially maintaining inappropriate hydrological where practices such as adjusted water management conditions). Providing a restoration site with a full tidal can increase carbon pools and or reduce GHG exchange offers the best opportunity for drawing in emissions. In natural wetlands actions should not sediment and establishing a healthy vegetation cover. be considered enhancement if they reduce other Vegetation vigour, and carbon production in soils will ecological functions and values (e.g. by introducing be reduced on sites where tidal hydrology is impaired.84 non native species or alter natural drainage). · Wetland Creation ­ Converting land from Human activities that positively influence wetlands and another non-wetland to a wetland where there was their carbon stocks fall into four potential categoriesg previously no wetland in existence. (definitions based upon a position paper by the Society of Wetlands Scientists on Restoration,85 and placed into As discussed in more detail in Chapter 5, there seems to a context for project activities for a carbon offset by be a discrepancy between definitions used by wetland wetland restoration and management context by PWA managers and restoration practitioners to describe and SAIC, 2009): wetland management activities and those definitions used within the wider context of the climate convention · Avoided Emissions and Wetland Loss ­ Conserv- as well as carbon markets. There is a need to address ing a wetland that would otherwise be converted these differences to allow for congruent development to a non-wetland. This includes actions to protect of practical management activities linked and driven in existing coastal wetlands and marine ecosystems, part by international policy, accounting and financial especially primary/intact systems, including mechanisms. those that face no immediate threat from loss and degradation but could in future be subject 3.4 Co-benefits of managing to land use pressures created by national and coastal wetlands and marine international leakage. This is particularly pertinent ecosystems for Climate Change to high coastal wetland distribution and currently mitigation low deforestation/degradation rate countries. See chapter 4.2 on expected future loss and degrada- Apart from their role in the carbon cycle, healthy tion of these areas. coastal wetlands and marine ecosystems underpin · Wetland Restoration ­ Actions taken in a converted or degraded natural wetland that result g The RAE Blue Ribbon Panel identified the need for clarification in the reestablishment of ecological processes, on project activity definitions and how each related to baseline functions, and biotic/abiotic linkages and leads to determination. 16 Environment Department Papers Avoiding Emissions and Increasing Carbon Sequestration society and economy, livelihoods and food security Table 3. Ecosystem Services of coastal through the services they provide (Table 3). and marine Ecosystems Ecosystem Mangroves act as natural barriers, serving as a first Services Coastal and Marine Environments Regulating Coastline protection from natural hazards defence from storm surges, stabilizing shorelines and Soil and beach erosion regulation reducing risk to coastal communities.86,87,88 Seagrass Land stabilization Climate regulation e.g. carbon sequestration meadows contribute to reducing shoreline erosion by Water quality maintenance trapping suspended sediments in their root systems.89 Provisioning Subsistence and commercial fisheries Aquaculture Coastal wetland and marine ecosystems absorb Medicinal products pollutants such as heavy metals as well as nutrients, Building materials Fuel wood suspended matter and pathogens, thus helping to Ornaments e.g. jewellery, decoration maintain water quality and prevent eutrophication Cultural Tourism Recreation and the development of dead zones.90 Their variety Spiritual i.e. Sacred and heritage sites of habitat supports high biological diversity and Aesthetic appreciation Supporting Nutrient recycling productivity, including nursery, spawning and feeding Nursery habitats habitats as well as shelter for numerous commercial Biodiversity species.91 Healthy and well functioning coastal (Modified from UNEP-WCMC, 2006) wetlands and marine ecosystems are highly important for around 15% of the world's population relying on Managing and protecting coastal wetlands and fish as their main or sole source of animal protein92 marine ecosystems for their carbon value will generate and in particularly coastal communities in developing significant co-benefits by reducing degradation and countries. Fisheries and related industries provide promoting the restoration and sustainable management direct employment to over 38 million people.93 of coastal wetlands and marine ecosystems. This Healthy coastal wetlands and marine ecosystems and reinforces socio-ecological resilience and reduces also provide a variety of recreational opportunities vulnerability to climate change impacts. Nature- such as snorkelling, recreational fishing and boating, based mitigation in coastal areas thus in many ways and coastal ecotourism is one of the fastest growing contributes to and strengthens Ecosystem-based sectors. Adaptation (EbA).94,95 Marine Ecosystem Series 17 Status and Trends of Coastal Wetlands and Near-Shore 4 Marine Ecosystems A s highlighted in the previous chapter, adequate 4.1.2 Seagrassmeadows management strategies for coastal wetlands and near-shore marine ecosystems provide Seagrass coverage is estimated to exceed 177,000 km2 for avoided emissions and increased carbon globally.102 Since the 19th century, the global coverage of sequestration. However many of these ecosystems are seagrass beds has declined by 29%, and the rate of loss disappearing at alarming rates. This chapter provides an is estimated to have increased by an order of magnitude overview of current global trends. in the past 40 years (Waycott et al 2009).103 In the South China Sea region, Indonesia has lost 30­40% of its seagrass beds, with almost 60% loss in Java. 4.1 Historical extent of Coastal Thailand has lost 20­30% of seagrass areas whereas wetland and marine ecosystems the Philippines have lost 30­50%.104 In the United and loss to Date States, historical seagrass cover has halved in Tampa Bay and 90% has been lost from Galveston Bay.105 Loss of 4.1.1 mangroves seagrasses over the last five decades ranges from 20% Mangroves, found in 123 countries, currently cover to 100% for most estuaries in the northern Gulf of about 150,000 km².96 Available data on historical and Mexico, with only a few areas experiencing increases.106 current mangrove distribution shows that its worldwide occurrence has been dramatically reduced, at least by S 4.1.3 altmarshesandfreshwatertidal a quarter but probably much more.97,98 Between 1980 marshes and 2005 35,000 km² of mangroves, representing one- fifth of the world's cover, was lost.99 Salt marshes and freshwater tidal marshes have lost a quarter of their historical global coverage107 with The rate of mangrove decline was the highest during a current rate of loss estimated at 1­2% per year. the 1980s, at an average of 1,850 km2 per year. The In southeast Australia, the loss of salt marshes from rate then dropped to 1,185 km2 in the 1990s and from estuaries is about 30% of their original area.108 In 2000­2005, it was 1,020 km2 per year.100 Although northern Europe over 5,000 km2 of wetlands have been worldwide degradation of mangroves seems to be drained.109 The diked coastal floodplain of the United slowing (see table 4), the rate is still high notably in States is about 50,000 km2 in size110, much of which Asia, which holds a large proportion of the world's would have been coastal wetlands.111 Rates of wetlands remaining mangroves (e.g. Indonesia has 21% of the loss in the U.S. and EU slowed dramatically with global mangrove cover). Overall the rate of loss is high the establishment of enforced protective legislation. in comparison to other habitats--mangrove forests Between 1950 and 1995, 22,000 km2 of salt marshes continue to vanish at a rate 3­4 times higher than and mangroves of mangroves were diked in China;112,113 forests on land.101 it is unclear what area of wetland remains. Marine Ecosystem Series 19 Mitigating Climate Change through Restoration and Management of Coastal Wetlands and Near-shore Marine Ecosystems The artificial draining of coastal wetlands leads to an aquaculture,121 overfishing and destructive fishing accumulation of sulphuric acid, iron and aluminium methods122 and, most recently, climate change.123 and the development of acid sulphate soils.114 This has Most seagrass habitats are lost due to degrading water a number of implications, including causing changes quality primarily caused by high nutrient runoff and in water quality and increasing the risk of algal blooms, sediment loadings.124 Direct damage from vessels, negatively affecting agriculture and aquaculture. dredging and trawling also greatly affect many seagrass habitats.125 4.2 Drivers of Coastal wetland and marine The loss and degradation of these ecosystems not only ecosystem loss contribute to climate change through increased carbon Many factors lead to the loss of coastal wetlands and emissions and deterioration of critical carbon sinks, but near-shore marine ecosystems, with anthropogenic also leads to an erosion of the many ecosystem services causes are the main drivers of change. Having been at on which society depends. the centre of human development for millennia, coastal wetlands are at risk globally from urban, industrial and 4.3 expected future loss and Degradation agricultural expansion and development. Sixty percent of the world's 39 largest metropolises are located in Models suggest that future coastal wetland loss through coastal areas, including 12 cities with populations of sea-level rise will reach 5­20% by 2080s,126 while more than 10 million people.115 To cope with high urban development will continue to pressure wetlands population growth and rapid urban development, coastal from land. One study predicts that by 2050 91% wetlands are often modified to allow for extended food of the world's coastlines will have been impacted by production and advanced infrastructure development development.127 The Global Biodiversity Outlook128 including housing, transportation and industry.116, 117 suggests that this `coastal squeeze' may cause coastal wetland systems to be reduced to narrow fringes The loss of coastal wetlands is caused by draining, by 2100, or be entirely lost locally.129,130 This will dredging, landfill as well as sediment diversion and increasingly put coastal communities and livelihoods at hydraulic alteration. Damming projects, for example, risk from marine hazards. have changed water flows and affected sediment delivery to river mouths and deltas, with recent Southeast Asia (notably Indonesia and Thailand, estimates showing a 30% global reduction of sediment Borneo and Sumatra), India, Bangladesh and delivery to coastal areas, impacting 47% of a rivers.118,119 West Africa are of particular concern. With rapid Many large deltas are under threat from such disruption population growth, limited land for agricultural and of sediment supply, some with almost total sediment urban expansion and difficulties in controlling coastal starvation, leaving habitats and human infrastructure development, the loss of wetlands in this regions is vulnerable to inundation and rising sea level.120 projected to continue at a relatively fast pace, leading to release of centuries to millennia of accumulated carbon Other drivers of the degradation and loss of in a few decades. marine ecosystems include the expansion of coastal 20 Environment Department Papers Policy Reform to Reduce Emissions 5 and Enhance Coastal Carbon Stocks T he concept of working with nature to reduce financing management and restoration of coastal GHG emissions--or using ecosystem-based wetlands and near-shore marine ecosystems for climate mitigation to progress overall climate change change mitigation. mitigation strategies-- is not new within the climate change convention. The UNFCCC as well 5.1 Opportunities for Developing as the Kyoto Protocol refer repeatedly to emissions Countries by sources and removals by sinks in natural systems. However, there are few incentives for coastal wetlands The UNFCCC, in Art 4.1(d), calls on all Parties to and near-shore marine ecosystems restoration or promote sustainable management, conservation and disincentives to drain or damage these systems. enhancement of GHG sinks and reservoirs in the Despite providing a provision to take action on coastal oceans as well as coastal and marine ecosystems. The and marine ecosystems in Art 4.1(d),h most of the Copenhagen Accord states that mitigation actions of definitions used throughout the Convention and in Non-Annex I Parties should be consistent with Art. 4.1 related reports (e.g. by IPCC) do not appear construed of the Convention. with the coastal and marine realm in mind. Taking into account Parties' common but Lessons learned from the forest sector indicate that differentiated responsibilities and their specific initial efforts to achieve international action on national and regional development priorities, deforestation within the UNFCCC failed due to weak objectives and circumstances (Art 4.1), opportunities carbon accounting methodologies available at the exist for developing countries to advance and time. Similarly, limited knowledge about the potential finance sustainable management, conservation and of coastal wetlands and near-shore marine ecosystems for enhancement of GHG sinks and reservoirs in coastal climate change mitigation and lack of applicable carbon wetlands and marine ecosystems. accounting methodologies has hampered progress so far. However, the scientific methods necessary to quantify, 5.1.1 ExtendingREDD+tocoastalEcosystems measure, and monitor carbon sequestration and GHG flux from coastal wetlands are achievable within existing After several years of negotiations Parties agreed at science.131 The available technology132 needs to be fully COP16 to a set of policy approaches and positive deployed in a coherent and programmatic global data gathering and assessment process. h UNFCCC Article 4.1(d): Promote sustainable management, and promote and cooperate in the conservation and This section reviews opportunities for addressing the enhancement, as appropriate, of sinks and reservoirs of all greenhouse gases not controlled by the Montreal Protocol, current gaps in UNFCCC processes based on the including biomass, forests and oceans as well as other terrestrial, Cancun Agreements and touches on possibilities for coastal and marine ecosystems. Marine Ecosystem Series 21 Mitigating Climate Change through Restoration and Management of Coastal Wetlands and Near-shore Marine Ecosystems incentives on issues relating to reducing emissions from The UNFCCC Subsidiary Body for Scientific and deforestation and forest degradation in developing Technological Advice (SBSTA)135 should also consider countries; and the role of conservation, sustainable including mangroves in its work programme, as management of forests and enhancement of forest outlined in Annex II to the REDD+ agreement. SBSTA carbon stocks in developing countries; also known as could for example identify land use, land-use change REDD+.133 and forestry activities that are linked to mangrove deforestation and degradation, identify methodological Developing countries are reporting their emission constraints to and approaches for estimating emissions estimates under REDD+ based on the IPCC guidelines and removals resulting from these activities. SBSTA and guidance on Agriculture, Forestry and Other Land could further develop, as necessary, modalities for Use (AFOLU) (see chapter 5.4). These guidelines measuring, reporting and verifying anthropogenic, and guidance define five carbon pools: aboveground mangrove forest-related emissions by sources and biomass, belowground biomass, dead wood, litter and removals by sinks; and similarly for mangrove forest soil organic matter. However, estimates from soil carbon carbon stock and mangrove forest area changes resulting are mostly not reported on in REDD+ assessments.134 from the implementation of activities, consistent with any guidance for measuring, reporting and verification When using IPCC guidelines certain carbon pools of nationally appropriate mitigation actions by may be omitted from reports if countries are able to developing country Parties. demonstrate that there are no emissions deriving from these pools. Emissions from soil carbon are however D 5.1.2 evelopmentofnewfinancial likely to be significant in the case of mangrove loss mechanisms or degradation. Incomplete REDD+ estimates are currently due to a lack of reliable data and incomplete The largest carbon deposits in coastal wetlands and methodological guidance from the IPCC. Additional near-shore marine ecosystems are found in below- methodological guidance from the IPCC on soil carbon ground biomass and sediment. However, existing is thus needed for countries to undertake complete financing mechanisms (such as REDD+) and the assessments of all carbon pools and to provide more methodological guidance they build upon (IPCC), accurate estimates of the reduction of emissions by are currently ill equipped to comprehensively account avoiding deforestation and forest degradation in for the soil organic carbon pool. This is making them mangroves and other forested areas. inapplicable for most coastal wetlands and near-shore marine ecosystems. Developing countries will, in general, need additional guidance and support in order to make full use of the While extending REDD+ to non-forested areas may opportunities of REDD+ in coastal areas. Support with time be possible, its structure and procedures could include relevant technical and technological could serve as an inspiration or model for development expertise enabling inclusion of mangroves in of international and national financing mechanisms REDD+ activities as agreed by the COP, such as the that incentivize policy and management measures for development of a national strategy or action plan, reducing GHG emissions from coastal carbon stocks a national forest reference level and a robust and and promote sequestration through conservation and transparent national forest monitoring system, and restoration. Any such mechanism should address the ensuring that the necessary environmental and social drivers of loss and degradation as well as account for safeguards, as lined out in Annex I to the REDD+ displacement of practices that would transfer GHG agreement, are adhered to. emissions to outside the project boundary (leakage). 22 Environment Department Papers Policy Reform to Reduce Emissions and Enhance Coastal Carbon Stocks It should also follow the principle of environmental emissions or restoration projects. Such projects could integrity and ensure that environmental and social contribute to a country's mitigation portfolio, while safeguards are put in place (e.g. safeguard against supporting low-carbon economies and sustainable restoration of ecosystems with non-native species). development pathways. Initiating projects as self- financed NAMAs, or as pilot initiatives within research Few studies have been conducted so far on the economic activities, could contribute to the development of more feasibility and viability of introducing coastal wetland robust accounting methodologies. This would, in the management projects into carbon markets. Existing longer-term, help move towards financially supported information indicates that current carbon prices could NAMAs with international monitoring, reporting outweigh the opportunity costs of other land-uses, and verification mechanisms in place, and eventually such as low and average income shrimp farming.136,137 towards a sector-wide financial mechanism. While it is clear that carbon emissions from drained coastal wetlands are sufficiently significant as to warrant 5.2 Opportunities for Developed Countries prioritized actions to bring them into financial offsetting mechanisms, it is unclear whether near-shore marine A 5.2.1 ccountingforcoastalwetlandsunder ecosystems such as seagrass beds will be immediately LULUcf attractive to financial markets. This is because the magnitude and fate of carbon released from seagrass The Kyoto Protocol contains provisions for Annex I soils are poorly understood, calling for quantitative Parties to adopt national policies and take measures assessment of the carbon balance in these habitats and to limit their anthropogenic emissions of GHGs and field methods to ground truth CO2 capture at specific protect and enhance their GHGs sinks and reservoirs sites. Even without this information, however, improved (Art. 2.1(a)). Parties to the Kyoto Protocol have to management would slow or reverse ongoing emissions account for the net changes in GHG emissions by and loss of sequestration capacity.138 Furthermore, there sources and removals by sinks resulting from direct may be some scope for including biodiversity premiums human-induced land-use change and forestry activities, for conservation of these habitats which are critical to limited to afforestation, reforestation and deforestation charismatic species like sea turtles, manatees, and other (Art. 3.3). Additionally, under Article 3.4, Parties may fauna, in addition to serving as feeding grounds for account for additional human-induced activities related commercially and ecologically important fish species. to land use, land-use change and forestry (LULUCF) specifically, forest management, cropland management, grazing land management and revegetation. When 5.1.3 nationalAppropriatemitigationActions LULUCF activities under Articles 3.3 and 3.4 result The Bali Action Plan identified National Appropriate in a net removal of GHGs, an Annex I Party can issue Mitigation Actions (NAMAs) as a means for removal units (RMUs) on the basis of these activities developing countries to enhance GHG emissions as part of meeting its commitment under Article 3.1. reduction required to achieve the main objective of the These units may be traded pursuant to the Kyoto's Convention. The Cancun Agreements now provide emissions trading scheme established under Article 17. an initial framework and guidance for developing countries wishing to implement and seek international GHG emissions by sources and removals by sinks in financial support for NAMAs. coastal and near-shore marine ecosystems resulting from human activities were not included in the Protocol's Developing countries could seize the opportunity to provisions and mechanisms of the first commitment define coastal wetland and seagrass focused avoided period. The rules and approaches governing LULUCF Marine Ecosystem Series 23 Mitigating Climate Change through Restoration and Management of Coastal Wetlands and Near-shore Marine Ecosystems and the inclusion of additional activities eligible in the This definition of "revegetation" does not seem to second commitment period are still being renegotiated have been developed with the coastal and near-shore under the Bali Action Plan. For the time being marine realm in mind. However, revegetation in coastal "Rewetting and drainage'"is included in brackets in the and near-shore marine ecosystems through natural KP negotiation text.139 recruitment of vegetation or active planting should be eligible under this definition. "Rewetting and drainage is a system of practices for rewetting and draining on land with organic Given the potential overlap between "rewetting and soil that covers a minimum area of 1 hectare. drainage" and "revegetation" in a coastal and near- The activity applies to all lands that have been shore marine context, relevant bodies under the drained and/or rewetted since 1990 and that UNFCCC (e.g. SBSTA) as well as other relevant are not accounted for under any other activity technical bodies such as the IPCC could be requested as defined in this annex, where drainage is the to identify and, as soon as possible, address the issue direct human induced lowering of the soil water of overlapping definitions within the Convention. table and rewetting is the direct human-induced This could also be done with respect to the divergence partial or total reversal of drainage"; of definitions related to coastal wetlands, wetland and marine management as used by UNFCCC and This definition is much narrower than definitions other multilateral environmental agreements and the of other wetland management activities Parties have scientific community.i discussed during the course of negotiations concerning a second commitment period of the Kyoto Protocol.140 The above definitions offer an opportunity to work However, "Rewetting and drainage" as described in this towards more comprehensive accounting under the definition could apply to drained coastal wetlands, a Kyoto Protocol, also considering ecosystems in the change from the current definition of LULUCF, which coastal and near-shore marine realms. However, as is very terrestrially orientated. Parties are encouraged mentioned above, all in all the Kyoto Protocol presently to accept "rewetting and drainage" as an activity under falls short of providing appropriate incentives to achieve LULUCF and construe the definition not only towards the goal of protecting and enhancing all natural sinks terrestrial wetlands but also towards the management of and reservoirs of GHGs. It deals with only a limited coastal wetlands as well. range of land--and seascapes and does not fully embrace a variety of natural sinks and reservoirs. The current KP draft proposal by the Chair141 refers to revegetation as Including new human activities into the LULUCF accounting system under the Kyoto Protocol is, "... a direct human-induced activity to increase however not without problems. Using LULUCF carbon stocks on sites through the establishment activities to meet emission reduction obligations of vegetation that covers a minimum area of is under scrutiny due to accounting loopholes-- 0.05 hectares and does not meet the definitions of LULUCF has by some standards become a means afforestation and reforestation contained here. It for developed countries to undermine the accuracy includes direct human-induced activities related of reports against emission reduction targets. It is to emissions of greenhouse gas and/or decreases feared that currently proposed revisions of LULUCF in carbon stocks on sites which have been categorized as revegetation areas and do not meet the definition of deforestation." i e.g. RAE Action Plan. 24 Environment Department Papers Policy Reform to Reduce Emissions and Enhance Coastal Carbon Stocks rules could allow for unaccounted GHG emissions Coastal wetland restoration and maintenance projects, from developed countries. Adding new activities into for example, have great potential to promote mitigation the LULUCF accounting system thus bears the risk while also providing co-benefits such as livelihood of endangering the integrity of a mitigation system support and shoreline protection. Notably, sustainable by including further opportunities for miscounting development is one of the core objectives of the CDM. GHG emissions and sinks. LULUCF rules should not lead to a decrease in the level of ambition of Annex The Ad-hoc Working Group on the Kyoto Protocol I countries to reduce GHG emissions from other (AWG-KP) currently considers whether SBSTA should sectors and should be as tight as possible to ensure initiate a work programme to consider, develop and environmental integrity. If, however, strong safeguards recommend modalities and procedures for possible e.g. on restoration practices are put in place, LULUCF additional LULUCF activities under CDM. LULUCF could become an important means for the protection activities eligible under the CDM are closely linked to and enhanced management of coastal wetlands as LULCUF activities listed under Art. 3.3 and 3.4 of the carbon reservoirs.142 It would therefore be desirable KP. If `rewetting and drainage' should not be included to move towards a more comprehensive accounting under Art. 3.4 it is unlikely that SBSTA would include system.143,144 this activity into its work plan. In current and future discussions regarding revision of LULUCF activities To include coastal wetlands and near-shore marine under a follow-up agreement to the Kyoto Protocol ecosystems more prominently into the LULUCF a broadening of the spectrum of activities to also accounting system it is recommendable that Parties include the coastal and near-shore marine areas seems work with the IPCC to revise existing methodologies warranted. for estimating anthropogenic GHG emissions by sources and removals by sinks resulting from LULUCF 5.3 expanding UnfCCC reporting activities, and develop supplementary methodologies requirements as necessary. Broadening the focus and including coastal wetlands and near-shore marine ecosystems in c 5.3.1 oastalwetlandsandnational the Kyoto Protocol accounting system would also be communications beneficial to activities beyond the Annex I framework (e.g. NAMAs). All Parties to the UNFCCC are required to submit national reports on the implementation of the Convention to the Conference of the Parties (COP) c 5.2.2 oastalwetlandmanagementascDm (UNFCCC Art. 4.1 and 12). Emissions and removals projects of GHGs are central in these national communication The Clean Development Mechanism (CDM) makes reports, although reporting requirements differ between provisions for the implementation of LULUCF project Annex I and non-Annex I countries (see reporting activities by Annex I Parties. CDM allows Annex I requirements Annex I in Chapter 8.3.1). countries to invest in GHG reduction projects in developing (non-Annex I) countries and have the The current reporting framework does not include credits count toward their emission reduction targets. a complete or up-to-date assessment of GHG LULUCF related CDM projects are presently limited emissions, goals, mitigation actions and their effects.145 to implementation projects involving afforestation and Negotiations indicate that current reporting guidelines reforestation and do not cover coastal wetlands or near- for national communications are to be revised. shore marine ecosystems. Modified national reports could provide a better and Marine Ecosystem Series 25 Mitigating Climate Change through Restoration and Management of Coastal Wetlands and Near-shore Marine Ecosystems more comprehensive way of assessing national and Use (IPCC GHGI for AFOLU)152 provides technical international progress towards the objectives of the guidance on estimating and reporting GHG emissions Convention and help to identify where such progress and removals through a Tiered approach, with increasing could be strengthened.146 level of detail and accuracy for each Tier. Tier 1 and 2 methods include soil organic stocks for mineral soils to a default depth of 30cm, with Tier 2 enabling inclusion of c 5.3.2 oastalwetlandsandnationalGHG greater depths if data are available. Residue/litter carbon inventories stocks are not included; these are measured separately Annex I Parties to the Convention are required to by estimating dead organic matter stocks. Stock changes submit to the UNFCCC secretariat national GHG in organic soils are estimated as annual loss of organic inventories of anthropogenic emissions by sources carbon throughout the profile due to drainage. Tier 3 and removals by sinks of GHGs not controlled by the methods can be used to refine estimates of the carbon Montreal Protocol. These inventories are coupled with stock changes in mineral and organic soils and soil requirements and decisions under the Kyoto Protocol inorganic carbon pools. Inventory classifications are and are subject to UNFCCC reporting guidelines.j based on land use areas that are stratified by climate The methodological elements of the guidelines, based regions and default soil types (for default classifications on IPCC Good Practice Guidance (GPG) for Land see IPCC GHGI for AFOLU Chapter 3, Annex 3A.5). use, Land-use Change and Forestry (IPCC GPG for LULUCF, 2004)147 are currently under revision by The complexity of incorporating wetlands management SBSTA,148 to address methodological issues related practices in national GHG inventories is recognized to reporting on emissions by sources and removals in Chapter 7 of the IPCC GHGI for AFOLU. Due to by sinks contained within the 2006 IPCC Guidelines the limited number of published studies, the guidance for National Greenhouse Gas Inventories with Volume on estimating and reporting emissions from managed 4 Agriculture, Forestry and Other Land Use (IPCC wetlands is focused on a restricted set of terrestrial GHGI for AFOLU).149 The process may provide wetland, specifically peatlands and flooded lands.k an opportunity to also consider coastal wetlands in Coastal wetlands do include soils that could fall under national GHG reporting.150 technical guidance for rewetting of peatland soils, and technical guidance provided in IPCC GHGI for AFOLU may be applied e.g.: 5.4 IpCC Guidance and Guidelines The IPCC provides scientific, technical and · Technical guidance on accounting for soil carbon methodological advice to the UNFCCC and has change within Generic Methodologies Applicable prepared guidelines that cover several aspects of GHG to Multiple Land-Use Categories (Chapter 2)153 accounting. This includes the 2004 IPCC Good · Technical guidance on reporting loss of soil carbon Practice Guidance for Land use, Land-use Change and with land use conversion croplands from wetlands Forestry (IPCC GPG for LULUCF),151 which provides (Chapter 4)154 guidance for measurement, estimation, assessment of uncertainties, monitoring and reporting of net carbon j "Guidelines for the preparation of national communications by stock changes and anthropogenic GHG emissions by Parties included in Annex I to the Convention, Part I: UNFCCC sources and removals by sinks in the LULUCF sector. reporting guidelines on annual inventories". k Guidelines are also provided for quantifying emissions of crop lands, seasonally flooded agricultural land, managed grasslands, The 2006 IPCC Guidelines for National Greenhouse Gas managed forests including drained forest wetlands, and rice Inventories Volume 4 Agriculture, Forestry and Other Land cultivation. 26 Environment Department Papers Policy Reform to Reduce Emissions and Enhance Coastal Carbon Stocks · Technical guidance on reporting GHG emissions climate change policy framework as well as in the from managed wetlands (Chapter 7)155 science community and among practitioners working on ecological restoration and management of coastal For example, the guidance in Chapter 2 related to soil wetlands. Such deliberations should also assess how organic carbon stock changes of mineral soils and CO2 marine ecosystems such as seagrass meadows and, emissions from organic soils due to enhanced microbial eventually, other oceanic systems, will fit into IPCC and decomposition associated with land use activities UNFCCC definitions and categories. enables accounting for the significant GHG emissions to the atmosphere arising from oxidation of soil carbon Reliable and accurate quantification and monitoring in drained coastal wetlands. of carbon sequestration in and GHG emissions from coastal wetlands are achievable within available However, while the technical guidance in principle technology and existing science.156,157 The challenge provides a foundation to account for carbon losses is to develop scientific approaches and make available through drainage of wetland soils, including coastal protocols and methodologies, the application of wetlands, this is challenged by limited availability of which does not incur prohibitive costs. Over recent datasets that would enable analysis at either Tier 1, years, GHG budgets have been quantified in a 2 or 3. Appropriate data collection programmes are number of locations and for a variety of coastal required to quantify soil carbon emissions for each wetland types through research (e.g. Chmura, et wetland type and setting. Further, it should also be al., 2003;158 Nelleman et al, 2009;159 Laffoley and noted that the default depth of 30 cm for soil carbon Grimsditch, 2009;160 PWA and SAIC, 2009.161 See content estimation is not suitable for coastal wetlands, also Table 2). A Blue Ribbon Panel in the USA has where drainage can occur to a depth of a meter or developed a programmatic Action Plan to deliver a more, leading to carbon loss to a great depth in the soil GHG offset protocol for tidal wetlands,162 including profile.l Marine ecosystems such as seagrass meadows establishment of working groups to tackle questions are presently not covered by existing IPCC guidance for related to definitions of project activities, eligibility, accounting and reporting. quantification, and permanence. A proposal to include a methodology for peat rewetting (applicable in coastal Revision of current IPCC guidance and guidelines and areas) has been released by the Voluntary Carbon the development of supplementary methodologies for Standards.163 A draft methodology for quantifying estimating GHG emissions by sources and removals GHG "Afforestation and reforestation of degraded tidal by sinks resulting from coastal wetland management forest habitats" has been submitted to the CDM board are highly desirable. This would, however, require for consideration. clarification and alignment of definitions used to describe types of wetlands as well as management While this provides ample material to draw upon, actions and project activities, within the international and the current process for revision and updating of IPCC documents offer an opportunity to address their apparent gaps with respect to coastal l Modeling of soil carbon dynamics within salt marshes is wetlands and marine ecosystem, a regular process currently underway in the US by the NCEAS Working Group developing a tidal wetlands carbon sequestration and greenhouse needs to be established for incorporating the gas emissions modeling. Model development is currently in findings from the growing body of scientific and calibration for case studies on the east, west and gulf coast of the methodological information on carbon pools and flux United States. This model will be applicable to tidal wetlands internationally, potentially including mangrove soils. http://www. in coastal wetlands as well as coastal and open-ocean nceas.ucsb.edu/projects/12503. ecosystems. Notably, additional work by the IPCC Marine Ecosystem Series 27 Mitigating Climate Change through Restoration and Management of Coastal Wetlands and Near-shore Marine Ecosystems on supplementary methodology will be beneficial for develop and review progress towards implementation any nature-based mitigation actions taken under the of an agenda encompassing science, economics and Convention. It is likely to have spillover effects on how policy. By informing international and national climate coastal wetlands and marine ecosystems will be dealt change policy processes it would support long-term with through other mechanisms, e.g. NAMAs and the and far-ranging action on coastal wetlands and marine MRV system. ecosystems for climate change mitigation. It would also offer a platform for bringing together and discussing findings of relevant ongoing international and national 5.5 Coordinated action activities, such as the establishment of a GHG offset Future action by the IPCC, UNFCCC SBSTA, methodology for rewetting and conserving peat.164 individual countries and organizations would greatly The Restore America's Estuaries National Blue Ribbon benefit from a coordinated effort bringing together Panel action plan to establish an offsets protocol for experts in coastal wetland and marine ecosystem temperate tidal wetlands165 is an example of such a science and management, GHG accounting, carbon coordinated initiative (see Annex 1 for detailed list of offset protocols and markets as well as international current activities). climate change policy. Such a grouping could help 28 Environment Department Papers 6 Conclusions and Recommendations C oastal wetlands and near-shore marine Advancing nature-based mitigation using coastal ecosystems hold vast stores of carbon. Occupying wetlands and marine ecosystems requires a range of only 2% of seabed area, vegetated wetlands priority actions, including: represent 50% of carbon transfer from oceans to sediments. This carbon can remain stored for 1. Additional research into and quantification of millennia. Drainage of coastal peatlands, forested carbon sequestration and storage in and GHG tidal wetlands, tidal freshwater wetlands, salt marsh emissions from key ecosystems, with a focus on and mangroves emits large amounts of CO2 directly poorly researched ecosystems and their mitigation to the atmosphere, and also leads to decreased carbon potential (e.g. sea grass beds); sequestration. Ongoing degradation and conversion 2. Continued development of carbon flux and carbon of coastal ecosystems and associated emissions and accounting methodologies (e.g. baseline data, lost sequestration are currently not recognized as a monitoring and verification approaches) for coastal significant driver of climate change, nor mitigated. wetlands and near-shore marine ecosystems; 3. Establishment of a network of projects to demon- Carbon emissions from drained coastal wetlands are strate proof-of-concept that coastal wetlands are sufficiently significant to warrant inclusion in carbon eligible under GHG mitigation and accounting accounting and inventories, development of financial approaches; incentive mechanisms, and amendment of national 4. Evaluation and development of financial incen- and international policy frameworks to reduce loss tive mechanisms including carbon offset trade, of these ecosystems. While further work is needed to also addressing issues such as project eligibility, identify the magnitude of emissions from near-shore additionally and permanence; marine ecosystems such as seagrass beds, it is clear that 5. Socioeconomic analysis of coastal and near-shore improved management of these ecosystems would marine carbon projects, including impacts on local slow or reverse current loss of carbon sequestration communities, livelihoods and industries; capacity. Sustainable management of coastal wetlands 6. Research into how different restoration and and near-shore marine ecosystems also offer a wide management approaches influence carbon flux in range of co-benefits, including shoreline protection, coastal and near-shore marine ecosystems; nutrient cycling, water quality maintenance, flood 7. Expansion of scientific understanding of large-scale control, habitat for birds, other wildlife and harvestable GHG pathways through oceanic systems, and resources such as fish. Together, these increase the exploration of policy frameworks to account for resilience of coupled ecological and social systems to the GHG regulation functions of ocean systems and impacts of climate change. incentives for securing these. Marine Ecosystem Series 29 Mitigating Climate Change through Restoration and Management of Coastal Wetlands and Near-shore Marine Ecosystems However, several opportunities exist to shape policies, 13. Harmonize currently used definitions and catego- develop financial incentives and apply carbon ries of activities as recognized under IPCC and management activities in the coastal realm in the near UNFCCC, as well as used in the science com- to medium-term. The following actions should be munity and in relation to ecological restoration considered: and management of coastal wetlands and marine ecosystems; 8. Include mangrove conservation and restoration 14. Revise the national climate change mitigation activities (including projects, capacity-building reporting process to also include action on the etc.) in national REDD+ strategies, policies and restoration and enhancement of coastal wetlands measures; and near-shore marine ecosystems. 9. Identify conservation and management actions for 15. Where possible, revise and extend current IPCC coastal wetlands and near-shore marine ecosystems guidance and guidelines to promote more com- as components of developing countries' National prehensive accounting of emissions by sources and Appropriate Mitigation Actions (NAMAs); removals by sinks in coastal wetlands and marine 10. Explore opportunities to develop a financial, pos- ecosystems, e.g. through establishment of Tier sibly REDD-like, approach for coastal wetlands and 1 definitions and methods for coastal wetlands; near-shore marine ecosystems that fall outside exist- and Develop supplementary methodologies for ing agreements and mechanisms, with a focus on estimating GHG emissions by sources and remov- providing financial incentives for soil-based carbon als by sinks covering additional coastal wetland storage and sequestration. This will require thorough and marine ecosystem types and management economic analysis and feasibility assessment. activities.m 11. Define `rewetting and drainage ' as an activity under LULUCF that encompasses both coastal and terrestrial wetlands in a second commitment period of the Kyoto Protocol; 12. Expand the SBSTA work programme to address possible additional LULUCF activities under the m IPCC GHGI for AFOLU have established methodologies for CDM, including modalities and procedures for assessing emissions from peatlands, grasslands, rice cultivation. more comprehensive accounting of anthropogenic Quantification of emissions from agricultural and other land- uses on sites that will be restored to coastal wetlands provide emissions from sources and removals by sinks in an established foundation for quantifying pre-project baseline coastal and near-shore marine ecosystems; emissions. 30 Environment Department Papers Annex 1 -- Current Coastal Carbon Activities F or some time academic research has focused The World Bank has supported research to on the significant capacity of coastal marine assess the potential for conservation and ecosystems for carbon storage and sequestration. restoration of marine systems, including complex However, it is only very recently that more marine foodwebs, to enhance the capture and attention is given to the development of adequate sequestration of CO2. The current study is a policy as well as management approaches. Current work product of that ongoing effort. on the potential for coastal carbon accounting and development of payment mechanisms includes: Based on the output from the California Climate Registry report, the NGO Restore America's In 2009 several initiatives have shown first results. Estuaries (RAE) sponsored a Blue Ribbon expert IUCN produced the report `The Management panel that met in late 2009. RAE is leading an of Natural Coastal Carbon Sinks', providing the initiative to develop a national greenhouse gas latest evidence of coastal ecosystems' ability to store offset protocol for coastal wetlands restoration and carbon and their role in reducing the negative effects recently released an `Action Plan to Guide Protocol of climate change. It offers specific policy guidelines Development'.168 http://estuaries.org/climate- about how to include management of marine change.html carbon sinks in international and national reduction strategies.166 The United Nations Environment A working group based at the National Center Programme (UNEP) produced the `Blue Carbon' for Ecological Analysis and Synthesis (NCEAS) report describing carbon sinks in the ocean.167 is currently focused on modeling greenhouse-gas exchanges to and from tidal marshlands with the Philip Williams and Associates (PWA) and Science goal of supporting possible development of carbon Applications International Corporation (SAIC) offsets in these systems. http://www.nceas.ucsb. prepared the report `Greenhouse Gas Mitigation edu/projects/12503 Typology Issues Paper: Tidal Wetlands Restoration' for the California Climate Registry. It focused The Marine Katoomba Group is continuing efforts on the potential for tidal wetlands based carbon which began at the Southeast Asia Katoomba offsets within the US regulatory system. This Meeting Mangrove Workshop in the larger context report was the first to describe issues related to of Payment for Ecosystems Services (PES) with developing a carbon offsets methodology for a focus on furthering the progress of mangrove wetlands particularly for restoration, avoided carbon methodology development and carbon loss, and wetlands enhancement, and outlined a emission reduction credits. suggested framework for developing a carbon offset methodology for tidal wetlands in the USA. Marine Ecosystem Series 31 Mitigating Climate Change through Restoration and Management of Coastal Wetlands and Near-shore Marine Ecosystems Conservation International, IUCN and the A team from the Nicholas Institute for Intergovernmental Oceanographic Commission, Environmental Policy Solutions and the Nicholas and partners, have established an international School of the Environment, Duke University is Blue Carbon Scientific Working Group as a review currently examining the economics of blue carbon and guiding body to improve carbon management sequestration and avoided emissions. A final report in coastal wetlands and seagrass ecosystems. This is due March 2011. Working Group first met February 2011 and will be meeting approximately biannually over the next These efforts demonstrate a growing interest in 3 years. http://www.marineclimatechange.com/ accounting for coastal and marine carbon sequestration marineclimatechange/bluecarbon_2.html and in developing mechanisms for carbon offsets, credits and payments in these natural systems. Experts A similar effort has been launched with a focus on meetings and their summary reports have so far Asia--the Asia-Pacific Blue Carbon Initiative-- concluded that there is strong potential for utilizing with support from UNEP/Grid Arendal. sequestered carbon in the management and sustainable funding of coastal conservation. 32 Environment Department Papers Annex 2 Derived Estimates of GHG Emissions from Coastal Carbon Sinks T his annex describes the methodology, analysis, methods and results of the technical analyses conducted in support of this report. The data emerging from For each delta, we calculated two curves that this analysis has been developed with the intent characterize subsided area and volume: (1) hypsometric of subsequent scientific peer review. curve and (2) stage-volume curve. The hypsometric curve is a cumulative distribution curve that tabulates elevation versus area. A point on the hypsometric background curve represents the area within the delta that lies Anthropogenic impacts to river and delta systems, below the specified elevation. The stage-volume curve such as the diking and draining of wetlands for tabulates elevation versus storage volume for a given agriculture, have resulted in significant loss of soil delta. The storage volume is the volume required to fill and carbon storage potential in the world's deltas. the subsided area back up to the specified elevation. Shrinkage due to dewatering, compression of peat Together, these two curves provide detailed information soils, oxidation, and other erosional processes about the distribution and depth of subsided areas (Holman 2009) have resulted in large subsided areas within a particular delta system. below natural marsh plain elevation in many deltas around the world. The purpose of this analysis is to Topography data were obtained from the NASA Shuttle develop a methodology to quantify the areal extent Radar Topography Mission (SRTM) datasets available and depth of delta subsidence, to quantify carbon through the ESRI Data and Maps DVDs packaged loss and emissions, and assess the restoration and with ArcGIS Version 9.3. Horizontal resolution for sequestration potential of tidal wetlands. This was the global dataset is 3 arc seconds (approximately accomplished by analyzing topographic data for 15 90m) and vertical resolution is 1m. The SRTM vertical representative case study deltas to serve as test cases datum is mean sea level based on the WGS84 Earth for the proposed methodology. Deltas were selected to Gravitational Model (EGM 96) geoid. obtain a representative sample over a wide geographic range, areal extent, degree of subsidence, tide range, The SRTM dataset, supplemented by satellite sediment supply, and sea level rise vulnerability, and imagery and watershed maps, was used to define the to draw on previous work by Coleman et al (2008) approximate extent of tidal influence for each of the and Syvitski et al (2009). The larger dataset of deltas 15 case study deltas. Since the primary areas of interest is included in Tables 1 and 2. The results provide were in diked and subsided areas that have been a rapid assessment of extent and depth of subsided reclaimed or separated from tidal action, the SRTM areas within each delta, estimates of carbon emissions water bodies layer was used to exclude lakes, rivers, from diked and drained areas, and estimates of carbon and ocean areas within the SRTM coverage area. For stored in existing wetlands. each delta, the resulting topography grid was analyzed Marine Ecosystem Series 33 Mitigating Climate Change through Restoration and Management of Coastal Wetlands and Near-shore Marine Ecosystems in ArcMap to produce hypsometry and stage-volume Table 5 shows the calculated values for the total curves to represent the extent and depth of subsidence subsided volume below marsh plain and the volume within each delta. Curves were calculated in 1m within the top 1.5m of subsided areas for each delta. increments from ­10m to +10m MSL. The volume of soil lost for organic (high carbon content) soils was assumed to be the full subsided To determine the extent and depth of subsidence relative depth, and was calculated as the full subsided to natural marsh plain, a literature review was conducted volume multiplied by the fraction of organics soils. to determine approximate tide ranges for each delta This assumption was based on observed patterns of system (Table 3). The typical spring tide level was selected subsidence and oxidation of peat soils, where carbon as a proxy for marsh plain elevation and each hypsometry reserves are continually depleted and soil is lost due to curve was shifted relative to the assumed marsh plain active land use practices and manipulation of the water elevation. Points were interpolated from the curves in 1m table. For the inorganic dominant soils (low carbon increments to determine subsided area and volume in 1m content), only the top 1.5m was assumed to be lost due bins relative to natural marsh plain elevation (Table 4). to its higher inorganic content. The volume of soil lost The stage-storage curves allow determination of the total for the inorganic soils was calculated as the subsided subsided volume within the delta below natural marsh volume in the top 1.5m multiplied by the percent plain elevation. These values are shown in Table 4 as the coverage (typically 50%). The remaining unaccounted volume below "Marsh plain 0m". for subsided volume is assumed to be volume loss due to dewatering, soil shrinkage, etc., and does not To derive estimates of green house gas emissions contribute to carbon emissions. released from coastal carbon sinks due to subsidence and oxidation of soils, the area and volume of each Total carbon loss from subsided soils was calculated subsided basin was converted to its equivalent carbon using the following formula (adapted from Holman storage. For each delta, we assumed that a mix of 2009): organic (high carbon content) and mineral (low carbon content) soils existed historically. In general, C =V x %C x x we assumed a 50/50 soil distribution split between the two soil types in each delta. The high carbon content where V = subsided volume, %C = organic carbon organic soils were assumed to be representative of highly content of soil, = bulk density (kg/m3), and = productive, backwater areas, with high accumulation carbon loss reduction factor equal to 0.5 for inorganic of organic matter. These soils were assumed to have a soils. The carbon loss reduction factor accounts for the 20% soil carbon density (weight to volume). The low fact that draining and subsidence of inorganic soils carbon content soils were assumed to be representative does not result in complete loss/oxidation of soils (i.e., of wetland areas with higher minerogenic (inorganic) some soil remains). For organic soils, the carbon loss sediment contributions, and lesser organic contributions reduction factor was assumed to be equal to 1.0. (6%). These soils were assumed to have lower carbon content. Few studies document the relative spatial restoration potential metrics distributions of these sediment types in the case study deltas under historic conditions. We selected a 50/50 Many world deltas are under threat by subsidence due split based on limited data to obtain first order estimates to a combination of land use practices (e.g., diking of soil carbon content. The Po and Sacramento Rivers, and draining for agriculture) and a lack of sediment where more detailed information was available, were availability due to upstream impoundment by dams. exceptions (Table 5). Former wetland areas that have been diked and drained 34 Environment Department Papers Annex 2 -- Derived Estimates of GhG Emissions from Coastal Carbon Sinks could potentially be restored through traditional area below marsh plain divided by volume below marsh restoration actions to reverse historical subsidence if plain. The index characterizes the general shape of the sufficient sediment is available to naturally aggrade the subsided portions of each delta (e.g., large shallowly ground elevation to levels where wetland vegetation subsided footprint vs. small deeply subsided footprint). can establish. For deeply subsided areas, or areas impacted by reduction of sediment, restoration through A low value of the index indicates that the subsided traditional methods may be unfeasible given the volume is large relative to the subsided area. A high magnitude of alterations to the historical landscape. The value of the index indicates that the subsided volume success of typical natural restoration actions is therefore is small relative to the subsided area. The index dependent upon adequate mineral sediment supply has important implications for the restorability of relative to the size of the subsided basin. In the absence wetlands within each delta. For low index deltas (e.g., of mineral sediment supply, historic carbon stocks can Vistula, Wash, Po, and Sacramento), large quantities be recovered through carbon farming and artificial of sediment would be required to fill subsided basins management of hydrology and vegetation growth. For that would produce relatively small areas of restored those deltas that are poor options for recovering natural wetlands. For high index deltas (e.g., Danube, Parana, carbon sinks through traditional restoration actions, and Orinoco), lesser quantities of sediment would be carbon farming techniques may provide a method of required to fill subsided basins that would produce sequestering large amounts of carbon and rebuilding relatively larger areas of restored wetlands. subsided areas back up to natural marsh plain elevations. This section describes the various metrics RestorableAreaindex developed in this study to quantify the likelihood of success of traditional restoration and carbon-farming The Restorable Area Index is determined from the techniques to rebuild wetland carbon sinks. subsided area values presented in Table 4. For each delta, the subsided area that falls between marsh plain Restoration potential scaling metrics were developed and 1m below marsh plain was determined. This area to assess the feasibility of restoring natural coastal was compared to the total subsided area for each delta. wetlands in diked and subsided areas within each The index was calculated by dividing the subsided area delta. The goal of the metrics is to help quantify within 1m of marsh plain by the total subsided area. and integrate characteristics of each delta such as The value of the index represents the fraction of the area and volume of subsided areas, sediment supply, entire subsided footprint that lies within 1m below and sea level rise migration area to assess the relative marsh plain. restoration feasibility within each delta. Each of the restoration potential metrics is described in detail A low value of the index indicates that the majority below. A discussion of how the metric is calculated, of the subsided area is relatively deeply subsided what it represents, and examples for particular systems and greater than 1m below the natural marsh plain are presented. The results of the index calculations are elevation (i.e., low restoration potential). A high value presented in Table 6 for each delta. of the index indicates that a large fraction of the total subsided area lies near (within 1m) of the natural marsh plain (i.e., high restoration potential). The AccommodationSpaceindex index has important implications for the restorability The Accommodation Space Index is determined from of wetlands within each delta. For low index deltas the subsided area and volume values presented in Table (e.g., Sacramento, Po, Wash, Vistula, and Humber), 4 for each delta. The index is calculated as the ratio of the majority of the subsided area is deeply subsided Marine Ecosystem Series 35 Mitigating Climate Change through Restoration and Management of Coastal Wetlands and Near-shore Marine Ecosystems and well below the natural marsh plain elevation. For transitionalAreaindex high index deltas (e.g., Congo, Orinoco, Danube, The Transitional Area index is determined by and Parana), a large portion of the subsided areas is comparing the footprint of the area within 1m above near marsh plain elevation (within 1m) and could existing marsh plain to the footprint of the full potentially be restored relatively easily given adequate subsided area. The index is calculated from the subsided sediment supply. Note that a low value of the index area values in Table 4. The index is calculated as the does not preclude restoration, it simply indicates footprint of the area between marsh plain and 1m that larger quantities of sediment may be required to above marsh plain divided by the full subsided area build up mudflat elevations to levels where vegetation footprint below marsh plain. The index represents the establishment can occur. area available for upslope migration of wetlands with sea level rise. SedimentSupplyindex A low value of the index indicates that there is poor The Sediment Supply Index is determined by migration capacity with future sea level rise. A high comparing the annual sediment delivery to the subsided value of the index indicates that there is good migration volume within each delta. The index is calculated from capacity. For low index deltas (e.g., Vistula, Po, and the average annual sediment discharge values in Table Sacramento), already subsided areas will become 3 and the subsided volume values in Table 4. The index even deeper with sea level rise and will become more is determined using two values for subsided volume: difficult to restore. For high index deltas (e.g., Congo, (1) full subsided volume below marsh plain and (2) Orinoco, Ganges-Brahmaputra, and Yangtze), already subsided volume within 1m of marsh plain. The index subsided areas will also become deeper with sea level is calculated as the annual sediment supply divided by rise, but additional area will be created near marsh plain the subsided volume. The index represents the amount elevation (by inundation and displacement of upland of inorganic sediment available to build up subsided habitats). For the low index deltas, restoration of areas to marsh plain elevation. vegetated marshes earlier, rather than later, will help to increase the resiliency of those systems to sea level rise A low value of the index indicates that there is very little because accumulation of organic material can augment sediment relative to the subsided volume within the natural sedimentation to help keep pace with sea level delta. A high value of the index indicates that there is a rise. For the high index deltas, earlier restoration is still higher sediment supply relative to the subsided volume desirable, but the consequences of delayed action (at within the delta. For low index deltas (e.g., Sacramento, least in terms of sea level rise resiliency) are less severe. Po, and Vistula), it is unlikely that there is sufficient sediment supply to naturally build up subsided areas Carbon sequestration metrics to marsh plain elevation. This could be due either to a greatly reduced sediment supply, or a vast subsided The metrics discussed above for restoration potential volume. For high index deltas (e.g., Congo, Orinoco, attempted to quantify the feasibility of restoration of Ganges-Brahmaputra, and Huang He), it is likely that subsided areas within each delta. The metrics helped there is adequate sediment supply to build up subsided characterize the shape of the subsided basins (broad and areas to marsh plain elevation. This could be due either shallow vs. narrow and deep), the footprint of restorable to an overwhelming sediment supply, or a relatively subsided areas near marsh plain, and the availability small subsided volume. Note that this index does not of sediment to build up subsided areas to vegetation take into account the amount of sediment required to colonization elevations. These metrics did not, however, maintain the existing delta function. quantify the potential or capacity to sequester carbon 36 Environment Department Papers Annex 2 -- Derived Estimates of GhG Emissions from Coastal Carbon Sinks within the deposited soils and organic material within footprints. In these systems, if managed freshwater each restored area. The carbon sequestration metrics restorations are feasible, large quantities of carbon could presented below are very similar to the restoration be sequestered per unit area of restored wetland due to metrics; however, they are interpreted differently to the deeply subsided nature of the sink. identify the sequestration potential of the subsided sinks within each delta. The results of the index SubsidedAreaandVolumeindices calculations are presented in Table 6 for each delta. The Restorable Area and Volume Indices area determined from the subsided area and volume values AccommodationSpaceindexfor presented in Table 4. For each delta, the subsided area carbonSequestration (volume) that falls within 1m below marsh plain was The Accommodation Space Index for Carbon determined. This area (volume) was compared to the Sequestration is determined from the subsided area and full subsided area (volume) for each delta. For each volume values presented in Table 4 for each delta. The delta, the subsided area (volume) within 1m of marsh index is calculated as the ratio of volume below marsh plain was divided by the full subsided area (volume). plain divided by area below marsh plain (note: this is This value was subtracted from 1.0 to determine the the reverse of the accommodation space index presented fraction of the entire subsided footprint (volume) that above for restoration metrics). The index characterizes is deeply subsided (i.e., deeper than 1m below marsh the general shape of the subsided portions of each delta plain). (e.g., large shallowly subsided footprint vs. small deeply subsided footprint), and can be thought of as the A low value of the index indicates that a large fraction "typical depth" of subsidence below marsh plain. of the subsided area (volume) lies near (within 1m) of the natural marsh plain. A high value of the index A low value of the index indicates that a large fraction indicates that the majority of the subsided area of the subsided area lies near (within 1m) of the (volume) is relatively deeply subsided and not near the natural marsh plain. A high value of the index indicates natural marsh plain elevation. The index has important that the majority of the subsided area is relatively implications for the feasibility of carbon sequestration deeply subsided and not near the natural marsh plain within each delta. For low index deltas (e.g., Congo, elevation. The index has important implications for the Orinoco, and Danube), the majority of the subsided carbon sequestration potential of wetlands within each area and volume is near marsh plain. This means that delta, assuming that managed freshwater restoration were these areas to be managed freshwater restorations, (e.g. "tule growth" to build up bed elevations through only limited amounts of organic material (and carbon) accumulation of organic matter) could occur within could be accumulated within the subsided basins before the subsided basins (the feasibility of this approach for marsh elevations would build up to natural marsh plain each delta is discussed elsewhere). For low index deltas elevation. For high index deltas, (e.g., Sacramento, (e.g., Danube, Parana, and Orinoco), the subsided areas Vistula, and Wash), the majority of the subsided area are large relative to the volume of organic material that and volume is much deeper than marsh plain, and vast could be accumulated to sequester carbon. This means potential carbon sequestration sinks exist. that large land areas must be acquired for relatively small amounts of carbon sequestration. For high index slr Vulnerability metrics deltas (Sacramento, Po, and Wash), the subsided volumes are vast and relatively large potential carbon Syvitski et al. (2009) analyzed the effects of human sinks exist, yet are contained within relatively small activities on delta subsidence, susceptibility to flooding, Marine Ecosystem Series 37 Mitigating Climate Change through Restoration and Management of Coastal Wetlands and Near-shore Marine Ecosystems and vulnerability to sea level rise. By considering assumption that organic poor-soils and organic-rich historic and present-day sediment supply, delta soils contain 6% and 20% carbon per dry weight of aggradation, subsidence, and relative sea level rise, the soil. We assume that low organic or mineral soils lose authors developed a classification scheme to determine only 50% of their carbon with drainage (Crooks, 1996, whether modern delta plains are keeping pace with 1999), but that organic rich soils lose all their carbon sea level. Deltas were classified into the following with drainage (Rojstaczer and Deverel, 1993; Deverel categories: not at risk, at risk, at greater risk, in peril, and Rojstaczer, 1996; Wösten et al., 1997; Holman and in greater peril. We have adopted this classification et al., 2009). We also assume that for a given coastal scheme as our scaling metric to assess the relative area high and low carbon content soils occur in a ratio vulnerability of our select deltas to future sea level rise. of 1:1. Soil types will vary across the landscape but this simple assumption is likely reasonable to provide a global estimate. In order to refine these estimates, a results better understanding of the organic content of wetland The results of the area and volume analysis, including soils specific to each region is required. We also made estimates of carbon dioxide emitted due to land use the assumption that natural vegetation colonization changes, are presented in Table 5 and Figure 1. The elevations equilibrate between mean high water restoration and carbon sequestration metrics are (MHW) and mean higher high water (MHHW), or presented in Table 6. The sea level rise vulnerabilities approximately at the typical spring tide elevation. A from Syvitski el al. (2009) are included in Table 2. more detailed understanding of natural marsh plain A summary of carbon stocks for large deltas with elevations specific to each delta would also help further remaining wetlands is presented in Table 7. refine this analysis. The analysis presented here is based on topography data Discussion from satellite remote sensing. It should also be noted Estimates of carbon content of wetland soils and that SRTM elevation data for areas of dense vegetation emissions associated with drainage of wetland soils cover (e.g. mangrove forests) might show a bias in the presented in this study compare well with similar topography dataset. In these areas, the areal extent estimates by other investigators (Drexler et al. 2009; of tidally influenced areas may be under-represented. Ong 2002; Fujimoto et al. 2001). The numbers Elevations in these areas should be ground-truthed to provided here may be considered conservative, allow further refinement of the estimates presented potentially on the low side. They are based upon an here. 38 Environment Department Papers Annex 2 -- Derived Estimates of GhG Emissions from Coastal Carbon Sinks Table 1. wetland loss (km2) and Average Annual rate of loss (km2y­1) determined by Time Series Imagery for 14 case Study deltas (coleman et al., 2008) Open Water Ag. and Ind. Use* Total Wetlands Area of Avg. Rate per Avg. Rate per Avg. Rate per Delta Delta Net Loss Year Net Loss Year Net Loss Year Mang.** Danube 83 6 83 6 3066 Ganges-Brahmaputra 783 65 3507 292 4290 358 5930 Huang He (Yellow) 8 1 727 66 735 67 1960 Indus 960 120 635 79 1595 199 1380 Mahanadi 116 39 22 7 94 31 1440 Mangoky 43 3 90 6 133 9 1449 McKenzie 24 12 24 12 995 Mississippi 252 21 112 9 364 30 1904 Niger 81 5 7 0.5 88 6 1110 Nile 2.4 0.2 12 0.7 14 0.8 872 Shatt el Arab 1610 101 5089 318 6699 419 1340 Volga 100 6 177 10 277 16 1420 Yukon 1100 157 1100 157 4654 Zambezi 24 2 325 23 349 25 2705 Total Loss 5104 10,786 15,845 30,225 Average Rate 41 68 95 * Agricultural and Industrial Use. ** Area of Delta Management Marine Ecosystem Series 39 Mitigating Climate Change through Restoration and Management of Coastal Wetlands and Near-shore Marine Ecosystems Table 2. characterizing delta vulnerability to Sea level rise as a result of reduced Sediment Supply (Syvitski et al., 2009) Recent Area of River Flooding Flooding (km2) Reduction (%) Reduction (%) Water, Oil and or Delta Flow rate (mmyr­1) rate (mmyr­1) Relative sea- Storm-Surge first-century Recent Area Gas Miningb aggradation aggradation Distributary Subsurface Area (km2)a Floodplain level (km2) above sea Area <2 m twentieth- Diversion Sediment level rise of in situ (mmyr­1) Channel Twenty- century Early- (km2) Delta Deltas not at risk: Aggradation rates unchanged, minimal anthropogenic subsidence Amazon 1,960c 0; LP 0 9,340 0 No 0 0 0.4 0.4 Unkn Congo d 460 0; LP 0 0 20 No 0 0 0.2 0.2 Unkn Fly 70c 0; MP 140 280 0 No 0 0 5 5 0.5 Orinoco 1,800c 0; MP 3,560 3,600 0 No 0 Unkn 1.3 1.3 0.8­3 Mahaka 300 0; LP 0 370 0 No Unkn 0 0.2 0.2 Unkn Deltas at risk: Reduction in aggradation, but rates still exceed relative sea-level Amur 1,250 0; LP 0 0 0 No 0 0 2 1.1 1 Danube 3,670 1,050 2,100 840 63 Yes 0 Minor 3 1 1.2 Han 70 60 60 0 27 No 0 0 3 2 0.6 Limpopo 150 120 200 0 30 No 0 0 7 5 0.3 Deltas at greater risk: Reduction in aggradation where rates no longer exceed relative sea-level Brahmani 640 1,100 3,380 1,580 50 Yes 0 Major 2 1 1.3 Godavari 170 660 220 1,100 40 Yes 0 Major 7 2 ­3 Indus 4,750 3,390 680 1,700 80 Yes 80 Minor 8 1 >1.1 Mahanadi 150 1,480 2,060 1,700 74 Yes 40 Mod 2 0.3 1.3 Parana 3,600 0; LP 5,190 2,600 60 No Unkn Unkn 2 0.5 2­3 Vistula 1,490 0; LP 200 0 20 Yes 75 Unkn 1.1 0 1.8 Deltas at peril: Reduction in aggradation plus accelerated compaction overwhelming rates of global sea-level rise Gangesd 6,170c 10,500 52,800 42,300 30 Yes 37 Major 3 2 8­18 Irrawaddy 1,100 15,000 7,600 6,100 30 No 20 Mod 2 1.4 3.4­6 Magdalena 790 1,120 750 750 0 Yes 70 Mod 6 3 5.3­6.6 Mekong 20,900 9,800 36,750 17,100 12 No 0 Mod 0.5 0.4 6 Mississippi 7,140c 13,500 0 11,600 48 Yes Unkn Major 2 0.3 5­25 Niger 350c 1,700 2,570 3,400 50 No 30 Major 0.6 0.3 7­32 Tigris d 9,700 1,730 770 960 50 Yes 38 Major 4 2 4­5 Deltas at greater peril: Virtually no aggradation and/or very high accelerated compaction Chao Pharya 1,780 800 4,000 1,600 85 Yes 30 Major 0.2 0 13­150 Colorado 700 0; MP 0 0 100 Yes 0 Major 34 0 2­5 Krishna 250 840 1,160 740 94 Yes 0 Major 7 0.4 ­3 Nile 9,440 0; LP 0 0 98 Yes 75 Major 1.3 0 4.8 Pearld 3,720 1,040 2,600 520 67 Yes 0 Mod 3 0.5 7.5 Po 630 0; LP 0 320 50 No 40 Major 3 0 4­60 Rhone 1,140 0; LP 920 0 30 No 40 Minor 7 1 2­6 Sao 80 0; LP 0 0 70 Yes 0 Minor 2 0.2 3­10 Francisco Toned 410 220 0 160 30 Yes Major 4 0 >10 Yangtzed 7,080 6,700 3,330 6,670 70 Yes 0 Major 1.1 0 3­28 Yellowd 3,420 1,430 0 0 90 Yes 80 Major 49 0 8­23 a LP: Little Potential; MP: Moderate Potential; SP: Significant Potential. b Unkn: Unknown; Mod: Moderate. c Significant canopy cover renders these SRTM elevation estimates conservative d Alternative names: Congo and Zaire; Ganges and Ganges-Brahmaputra; Pearl and Zhujiang; Tigris and Tigris-Euphrates and Shatt al Arab; Tone and Edo; Yangtze and Changjiang; Yellow and Huanghe. The Tone has long had its flow path engineered, having once flowed into Tokoyo Bay; the number of distributary channels has increased with engineering works. 40 Environment Department Papers Annex 2 -- Derived Estimates of GhG Emissions from Coastal Carbon Sinks Table 3. Summary of Scaling metrics for Sea level rise vulnerability and restoration potential for Select deltas Average Average Subsided Subsided Annual Annual Area (below Volume (below Freshwater Sediment Tide Marshplain marshplain) marshplain) Discharge Discharge Range Elevation Elevation Elevation Delta Country Receiving Basin (m3/s) (Mt/yr) (m) (m MSL) (km2) (Mm3) Congo DRC Atlantic Ocean 39,600 43 1.5 0.8 30 10 (Zaire) Orinoco Venezuela Atlantic Ocean 28,900­34,900 150 1.8 0.9 420 210 Danube Romania Black Sea 6,500 67­122 0.0 0.0 3,560 750 Indus Pakistan Arabian Sea 2,650 59­100 3.5 1.8 5,360 3,580 Parana Argentina Atlantic Ocean 17,300 79 0.6 0.3 400 160 Vistula Poland Baltic Sea N/A 2.5 0.1 0.05 1,290 2,150 Humber UK North Sea N/A N/A 5.7 2.9 960 1,140 Wash UK North Sea N/A N/A 6.5 3.3 3,330 6,550 Ganges- Bangladesh/ Bay of Bengal 29,700­30,800 1050­1620 4.0 2.0 4,190 3,240 Brahmaputra India Mekong Vietnam South China Sea 10,300­14,900 160­170 3.0 1.5 18,790 21,060 Nile Egypt Mediterranean Sea 2,780 0 0.4 0.2 5,200 5,390 Po Italy Adriatic Sea 1,500 13­18 0.6 0.3 3,440 8,090 Changjiang China East China Sea 25,100­29,200 100­150 3.5 1.8 24,430 25,300 (Yangtze) Huang He China Bohai Sea 1,300­2,600 1060­1100 1.4 0.7 2,190 1,280 (Yellow) Sacramento USA San Francisco Bay 850 1­3 1.2 0.6 1,490 4,270 Freshwater and Sediment Discharge Sources: Correggiari et al 2001, Domagalski and Brown 1998, Liu et al 2009, LSU World Delta Database, Meade and Milliman 1983, Milliman and Mei-e 1995, Milliman and Syvitski 1992, Nelson 1970, Scott and Schoelhammer 2004, Wright and Nittrouer 1995. Tide Range Sources: LSU World Deltas Delta Database, NOAA-NOS Tides and Currents, Walsh and Nittrouer unpublished manuscipt, Wright and Nittrouer 1995. Note: Tide range indicates typical spring tide range. Marine Ecosystem Series 41 42 Table 4. Summary of Scaling metric for Sea level rise vulnerability and restoration potential for Select deltas Area (km2) Volume (Mm3) Marshplain Elevation Marshplain Marshplain Delta (m MSL) +1m 0m ­1m ­2m ­3m ­4m ­5m +1m 0m ­1m ­2m ­3m ­4m ­5m Congo (Zaire) 0.8 99 26 3 0 0 0 0 63 13 2 1 0 0 0 Orinoco 0.9 1,563 416 47 9 5 3 2 1,006 205 33 16 10 7 5 Danube 0 4,531 3,561 472 36 4 1 1 4,634 753 88 12 4 2 1 Indus 1.8 7,788 5,363 2,398 558 49 26 15 9,253 3,576 910 142 76 46 29 Parana 0.3 1,881 402 30 4 2 1 1 1,066 158 15 7 4 3 2 Vistula 0.05 1,457 1,293 934 634 263 53 3 3,504 2,154 1,149 428 87 8 1 Humber 2.9 1,260 957 602 240 48 2 0 2,214 1,144 424 96 6 1 0 Wash 3.3 3,864 3,330 2,523 1,675 979 320 84 10,072 6,547 3,782 1,880 704 178 47 Ganges- 2 9,409 4,186 1,707 652 37 10 5 8,636 3,243 996 96 33 20 14 Brahmaputra Mekong 1.5 27,638 18,793 9,694 3,435 1,086 412 168 42,884 21,064 8,320 2,827 1,082 462 218 Nile 0.2 7,792 5,200 2,304 1,191 706 406 173 11,106 5,394 2,846 1,537 759 305 97 Po 0.3 3,997 3,440 2,581 1,862 1,296 808 397 11,757 8,088 5,269 3,191 1,711 750 236 Changjiang 1.8 34,780 24,431 16,001 6,612 774 152 14 50,430 25,300 8,850 1,086 268 103 88 (Yangtze) Huang He 0.7 3,749 2,188 938 104 38 18 9 3,628 1,284 242 100 49 26 15 (Yellow) Sacramento 0.6 1,752 1,486 1,145 836 653 485 326 5,869 4,267 2,991 2,062 1,338 789 404 Mitigating Climate Change through Restoration and Management of Coastal Wetlands and Near-shore Marine Ecosystems Environment Department Papers Table 5. Summary of carbon lost from world deltas Contributing Volume Soil Distribution to Carbon Loss Carbon loss Carbon Dioxide Emitted Total Subsided Subsided Vol. in top Fractional Volume 1.5m Marshplain Volume Loss to Organic Inorganic Organic Inorganic Total Organic Inorganic Total Delta (Mm3) (Mm3) Area (km2) Other Factors Organic Inorganic (Mm3) (Mm3) (Mt C) (Mt C) (Mt C) (Mt CO2) (Mt CO2) (Mt CO2) Deltas not at risk Marine Ecosystem Series Table 4. 13 12 26 4% 50% 50% 6 6 0.4 0.1 0.6 1 1 2 Summary of scaling Orinoco 205 181 416 6% 50% 50% 103 90 6 3 9 23 12 34 Deltas at risk Danube 753 703 3,561 3% 50% 50% 377 352 23 13 35 83 46 129 Deltas at greater risk Indus 3,576 3,050 5,363 7% 50% 50% 1,788 1,525 107 55 162 393 201 594 Parana 158 147 402 3% 50% 50% 79 74 5 3 7 17 10 27 Vistula 2,154 1,365 1,293 18% 50% 50% 1,077 683 65 25 89 236 90 326 Humber 1,144 884 957 11% 50% 50% 572 442 34 16 50 126 58 184 Wash 6,547 3,716 3,330 22% 50% 50% 3,274 1,858 196 67 263 719 245 964 Deltas in peril Ganges- 3,243 2,697 4,186 8% 50% 50% 1,662 1,349 97 49 146 356 178 534 Brahmaputra Mekong 21,064 15,490 18,793 13% 50% 50% 10,532 7,745 632 279 911 2,313 1,021 3,333 Deltas in greater peril Nile 5,394 3,203 5,200 20% 50% 50% 2,697 1,602 162 58 219 592 211 803 Po 8,088 3,859 3,440 13% 75% 25% 6,066 965 364 35 399 1,332 127 1,459 Changjiang 25,300 20,332 24,431 15% 75% 6,325 15,249 380 549 928 1,389 2,009 3,398 (Yangtze) Huang He 1,284 1,113 2,188 10% 25% 75% 321 835 19 30 49 70 110 180 (Yellow) Sacramento 4,267 1,741 1,486 0% 100% 0% 4,267 0 256 0 256 937 0 937 Total 83,192 58,494 75,071 39,106 32,773 2,346 1,180 3,526 8,588 4,318 12,906 Notes: 1. Volume and mass units are as follows. Mm3 = million cubic meters, Mt C = millon metric tonnes of carbon. 2. Contributing volume for carbon loss determined as follows. For organic soil areas, the full subsided volume is assumed to contribute to carbon loss. For inorganic soil areas, only half of the top 1.5m of subsided volume is assumed to contribute to carbon loss. 3. Soil carbon density for organic and inorganic soils assumed to be 20% and 6% respectively, weight to volume. 4. Bulk density assumed to be 200 kg/m3 for organic and 1200 kg/m3 for inorganic soils. 5. CO2 emissions calculated by multiplying kg C by a factor of 3.66. 6. Fractional volume loss to other factors includes shrinkage due to dewatering, compression and compaction, etc. 43 Annex 2 -- Derived Estimates of GhG Emissions from Coastal Carbon Sinks 44 Table 6. Summary of Scaling metrics for Sea level rise vulnerability and restoration for Select deltas Restoration Metrics Restoration Assessment Carbon Farm Metrics Carbon Farm Assessment Space Index Accommodation Index Restorable Area Index (Whole Delta) Sediment Supply (Shallow Delta) Sediment Supply Area Index Space Index Accommodation Index Restorable Area SLR Transitional Index (Whole Delta) Sediment Supply (Shallow Delta) Sediment Supply Area Index SLR Transitional Total Space Index Accommodation Index Subsided Area Index Subsided Volume Space Index Accommodation Index Subsided Area Index Subsided Volume Total Deltas not at risk Congo (Zaire) 2.06 0.89 3.38 3.85 2.77 0 1 1 1 1 4 0.49 0.11 0.12 ­1 ­1 ­1 ­3 Orinoco 2.03 0.89 0.73 0.87 2.75 1 1 1 1 1 5 0.49 0.11 0.16 ­1 ­1 ­1 ­3 Deltas at risk Danube 4.73 0.87 0.126 0.143 0.27 1 1 0 0 ­1 1 0.21 0.13 0.12 ­1 ­1 ­1 ­3 Deltas at greater risk Indus 1.50 0.55 0.022 0.030 0.45 0 0 0 0 ­1 ­1 0.67 0.45 0.25 ­1 0 ­1 ­2 Parana 2.54 0.93 0.50 0.55 3.68 1 1 0 0 0 2 0.39 0.07 0.10 ­1 ­1 ­1 ­3 Vistula 0.60 0.28 0.001 0.002 0.13 ­1 ­1 ­1 ­1 ­1 ­5 1.67 0.72 0.53 0 1 0 1 Humber 0.84 0.37 N/A N/A 0.32 ­1 ­1 1 1 ­1 ­1 1.20 0.63 0.37 0 0 ­1 ­1 Wash 0.51 0.24 N/A N/A 0.16 ­1 ­1 0 0 ­1 ­3 1.97 0.76 0.58 0 1 0 1 Deltas in peril Ganges-Brahmaputra 1.29 0.59 0.34 0.49 1.25 0 0 1 1 1 3 0.77 0.41 0.31 ­1 0 ­1 ­2 Mekong 0.89 0.48 0.008 0.013 0.47 ­1 0 ­1 0 ­1 ­3 1.12 0.52 0.39 0 0 ­1 ­1 Deltas at greater peril Nile 0.96 0.56 0.000 0.000 0.50 ­1 0 ­1 ­1 ­1 ­4 1.04 0.44 0.53 0 0 0 0 Po 0.43 0.25 0.002 0.006 0.16 ­1 ­1 ­1 ­1 ­1 ­5 2.35 0.75 0.65 1 1 0 2 Changjiang (Yangtze) 0.97 0.35 0.005 0.008 0.42 0 0 0 0 1 1 1.04 0.65 0.35 ­1 0 ­1 ­2 Huang He (Yellow) 1.70 0.57 0.84 1.04 0.71 0 0 1 1 ­1 1 0.59 0.43 0.19 ­1 0 ­1 ­2 Sacramento 0.35 0.23 0.0005 0.0016 0.18 ­1 ­1 ­1 ­1 ­1 ­5 2.87 0.77 0.70 1 1 0 2 Note: SLR vulnerability integrates impact of global sea level rise, delta subsidence, and sediment supply (Syvitski et al 2009). Mitigating Climate Change through Restoration and Management of Coastal Wetlands and Near-shore Marine Ecosystems Environment Department Papers Annex 2 -- Derived Estimates of GhG Emissions from Coastal Carbon Sinks Table 7. Summary of carbon Stocks for large deltas with remaining wetlands Stored Carbon Stored Carbon Stored Carbon (Plants) (Soils) (Soils + Plants) Total Marshplain Inorganic Inorganic Organic Inorganic Organic Inorganic Carbon Total CO2 Delta Area (km2) (Mt C) (Mt CO2) (Mt C) (Mt C) (Mt CO2) (Mt CO2) (Mt C) (Mt CO2) Table 4. Summary of scaling metrics for sea level rise vulnerability and restoration potential for select deltas Congo (Zaire) 25­95 0­1 1­3 2­7 1­3 6­25 2­9 2­9 9­40 Orinoco 370­1,515 3­10 10­45 30­110 10­40 95­400 40­150 40­145 145­595 Deltas at greater risk Indus 2,965­5,390 25­45 90­160 215­390 80­150 780­1,420 295­535 320­1,120 1,160­2,110 Parana 370­1,850 3­15 10­55 30­135 10­50 100­490 40­185 40­150 145­725 Deltas in peril Ganges- 2,480­7,700 20­60 70­225 180­225 70­120 655­2,030 245­760 265­960 970­3,020 Brahmaputra Total 6,210­16,550 50­130 180­490 460­1,200 170­450 1,635­4,365 620­1,640 670­2,385 2,430­6,490 Notes: 1. Mass units are as follows: Mt C = Million metric tons of Carbon, Mt CO2 = Million metric tons of Carbon dioxide. 2. Future subsided volume calculated assuming approximately 1 in/yr subsidence rate over 50-year period to yield approximately 1.5 m year of subsidence. 3. CO2 emissions calculated by multiplying kg C by a factor of 3.66. 4. Lower estimate of marshplain area taken as area between marshplain and 1m below marshplain. Upper estimate taken as area between +/­ 1m marshplain. Marine Ecosystem Series 45 References Coleman, J. M., & Wright, L. D. (1971) Analysis of Domagalski, J.L., and Brown, L.R., (1998) National major River Systems and Their Deltas: Procedures and Water-Quality Assessment Program--The Sacramento Rationale, with Two Examples. 125p. Baton Rouge: River Basin: U.S. Geological Survey Fact Sheet FS Louisiana State University, Coastal Studies Institute. 94­029, 2 p. Coleman, J. M., Huh, O. K., & Braud, D. J. (2008) Drexler, J.Z., de Fontaine, C.S., and Deverel, S. (2009) Wetland Loss in World Deltas. Journal of Costal The legacy of wetland drainage on the remaining peat Research, 24 (1A), 1­14. in the Sacramento-San Joaquin Delta, CA, USA. Wetlands 29(1), pp. 372­386. Correggiari, A., Trincardi, F., Langone, L., Roveri, M., (2001) Styles of failure in late Holocene high Fujimoto, K., Imaya, A., Tabuchi, R., Kuramoto, S., stand prodelta wedges on the Adriatic shelf. Journal of Utsugi, H. & Murofushi, T. (2001) Below ground Sedimentary Research 71, 218­236. carbon storage of Micronesian mangrove forests. Ecological Research, 14, 409­413. Crooks, S. (1996) Sedimentological Controls on the Geotechnical Properties of Intertidal Saltmarsh and Hart, G. F., & Coleman, J. The World Deltas Database Mudflat Deposits. PhD Thesis, University of Reading, Framework. Retrieved 2010, from Louisiana State U.K. University: www.geol.lsu.edu/WDD Crooks, S., (1999) A mechanism for the formation of Holman, I. (2009) An Estimate of Peat Reserves and overconsolidated horizons within estuarine floodplain Loss in the East Anglian Fens Commissioned by the alluvium: implications for the interpretation of RSPB. Cranfield University. Holocene sea level curves. In: S.B. Marriott and J. Alexander (eds.) Floodplains: Interdisciplinary Liu, J.P., Xue, Z., Ross, K., Wang, J., Yang, Z.S., Li, Approaches. Geological Society Special Publication No. A.C., Gao, S. (2009) Fate of sediments delivered to 163. the sea by Asian large rivers: Long-distance transport and formation of remote alongshore clinothems. The Deverel, S. J., & Rojstaczer, S. (1996) Subsidence of Sedimentary Record. Volume 7, No. 4. December 2009. Agricultural Lands in the Sacramento-San Joaquin pp. 4­10. Delta, California: Role of Aqueous and Gaseous Carbon Fluxes. Water Resources Research, 32 (8), Milliman, J. D., & Meade, R. H. (1983) World-Wide 2359­2367. Delivery of River Sediment to the Oceans. The Journal of Geology, 91 (1), 1­20. Marine Ecosystem Series 47 Mitigating Climate Change through Restoration and Management of Coastal Wetlands and Near-shore Marine Ecosystems Milliman, J. D., & Mei-e, R. (1995) River Flux to the Rojstaczer, S., & Deverel, S. J. (1993) Time Sea: Impact of Hman Intervention on River Systems Dependence in Atmospheric Carbon Inputs from and Adjacent Coastal Areas. In Climate Change: Drainage of Organic Soils. Geophysical Research Letters, Impact on Coastal Habitation (pp. 57­83). CRC Press, 20 (13), 1383­1386. Inc. Syvitski, J. P., Kettner, A. J., Overeem, I., Hutton, E. Milliman, J. D., & Syvitski, J. P. (1992) Geomorphic/ W., Hannon, M. T., Brakenridge, G. R., et al. (2009) Tectonic Control of Sediment Discharge to the Ocean: Sinking Deltas Due to Human Activities. Nature The Importance of Small Mountainous Rivers. The Geoscience, 2, 681­686. Journal of Geology, 100, 525­544. Wösten, J.H.M., Ismail, A.B., and Van Wijk, A.L.M. Nelson, B. W. (1970) Hydrography, Sediment (1997) Peat subsidence and its practical implications: a Dispersal, and Recent Historical Development of the case study in Malaysia. Geoderma 78, pp. 25­36. Po River Delta, Italy. In J. P. Morgan, & R. H. Shaver, Deltaic Sedimentation, Modern and Ancient (Vol. 15, Wright, L. D., & Nittrouer, C. A. (1995) Dispersal of pp. 152­184). The Society of Economic Paleontologists River Sediments in Coastal Seas: Six Contrasting Cases. and Mineralogists. Estuaries, 18 (3), 494­508. Ong, J.E. (2002) The hidden costs of mangrove Wright, S.A. and Schoellhamer, D.H. (2004) Trends in services: use of mangroves for shrimp aquaculture. the Sediment Yield of the Sacramento River, California, International Science Roundtable for the Media. Bali, 1957­2001. San Francisco Estuary & Watershed Indonesia. June 4, 2002. Science [online]. Vol. 2, Issue 2 (May 2004), Article 2. 48 Environment Department Papers Sources Cited 1 Laffoley, D. & Grimsdicth, G. (Eds.) 2009. The 7 Philips Williams & Associates (PWA), Ltd & Science Management of Natural Coastal Carbon Sinks. IUCN, Applications International Corporation (SAIC) (2009) Gland, Switzerland, 53pp. http://cmsdata.iucn.org/ Greenhouse Gas Mitigation Typology Issues Paper Tidal downloads/carbon_managment_report_final_printed_ Wetlands Restoration. Prepared for California Climate version.pdf Action Registry. http://www.climateactionreserve. org/wp-content/uploads/2009/03/future-protocol- 2 Nellemann, C., Corcoran, E., Duarte, C. M., Valdés, development_tidal-wetlands.pdf L., De Young, C., Fonseca, L., Grimsditch, G. (Eds). 2009. Blue Carbon. A Rapid Response Assessment. 8 Spalding, M., Kainuma, M., Collins, L. (2010) United Nations Environment Programme, GRID- World atlas of mangroves. ITTO, ISME, FAO, Arendal,http://www.grida.no/publications/rr/blue- UNEP-WCMC, UNESCO-MAB and UNU-INWEH. carbon/ Earthscan UK, USA. 3 The World Bank, 2010a. World Development 9 Coleman, J.M., Huh, O.K., Braud Jr., D. (2008) Report 2010: Development and Climate Change. Wetland loss in world deltas. Journal of Coastal The International Bank for Reconstruction and Research. 24(1A), 1­14 Development: Washington, D.C. 10 Syvitski, J.P.M., Kettner, A. J., Overeem, I., 4 The World Bank 2010b. Convenient Solutions to Hutton, E. W., Hannon, M. T., Brakenridge, G. R., an Inconvenient Truth: Ecosystem-Based Approaches Day, J., Vörösmarty, C., Saito, Y., Giosan, L.,and to Climate Change. The International Bank for Nicholls, R.J. (2009) Sinking deltas due to human Reconstruction and Development: Washington, D.C. activities. Nature Geoscience. 2, 681­686. 5 Capturing and conserving natural coastal carbon: 11 Spalding, M., Kainuma, M., Collins, L. (2010) building mitigation, advancing adaptation. The World World atlas of mangroves. ITTO, ISME, FAO, Bank, ICUN, EXA PWA, 2010. http://cmsdata.iucn. UNEP-WCMC, UNESCO-MAB and UNU-INWEH. org/downloads/capturing_and_conserving_natural_ Earthscan UK, USA. coastal_carbon___building_mitigation___advancing_ ada.pdf 12 Waycott, M., Duarte, C. M., Carruthers, T. J. B., Orth, R. J., Dennison, W. C., Olyarnik, S., Calladine, 6 Duarte, C.M., Middelburg, J.J., Caraco, N. (2005) A. Fourgqurean, J. W., Heck, Jr., K. L., Hughes, A., R., Major Role of Marine Vegetation on the Oceanic Kendrick, G. A., Kenworthy, W. J., Short, F. T., and Carbon Cycle. Biogeosciences 2:1­8. Williams, S. L. (2009) Accelerating loss of seagrasses across Marine Ecosystem Series 49 Mitigating Climate Change through Restoration and Management of Coastal Wetlands and Near-shore Marine Ecosystems the globe threatens coastal ecosystems. Proceedings of In W.D. Larkum, R.J. Orth & C.M. Duarte (eds.) the National Academy of Sciences, 106 (doi:10.1073. Seagrasses: Biology, Ecology and Conservation. pnas.0905620106) Springer 567­593. 13 IPCC (2007) Climate Change 2007: Synthesis 20 Duarte, C. M., and J. Cebrián. 1996. The fate Report. Contribution of Working Groups I, II of marine autotrophic production. Limnology and and III to the Fourth Assessment Report of the Oceanography. 41, no. 8: 1758­66; Intergovernmental Panel on Climate Change [Core Writing Team, Pachauri, R.K and Reisinger, A. (eds.)]. 21 Crooks, S. (1996) Sedimentological Controls on IPCC, Geneva, Switzerland, 104 pp. the Geotechnical Properties of Intertidal Saltmarsh and Mudflat Deposits. PhD Thesis, University of Reading, 14 Chen, C.-T.A. and Borges, A.V. (2009) Reconciling U.K. opposing views on carbon cycling in the coastal ocean: Continental shelves as sinks and near-shore ecosystems 22 Crooks, S. (1999) A mechanism for the formation as sources of atmospheric CO2. Deep Sea Research II, of overconsolidated horizons within estuarine 56, 578­590. floodplain alluvium: implications for the interpretation of Holocene sea level curves. In: S.B. Marriott and 15 Nagelkerken, I., van der Velde, G., Gorissen, M.W., J. Alexander (eds.) Floodplains: Interdisciplinary Meijer, G.J., van't Hof, T. and den Hartog, C. (2000) Approaches. Geological Society Special Publication No. Importance of mangroves, seagrass beds and the shallow 163. coral reef as a nursery for important coral reef fishes, using visual census techniques. Estuarine, Coastal and 23 Andrews, J. E., Samways, G., Dennis, P.F. & Shelf Science., 51, 31­44. Maher, B.A. (2000) Origin, abundance and storage of organic carbon and sulphur in the Holocene Humber 16 Pergent, G., Romero, J., Pergent-Martini, C., Estuary: emphasizing human impacts on storage Mateo, M.A. & Boudouresque, C-F. (1994) Primary change. Geological Society, London Special Issue. 2000. Production, stocks, and fluxes in the Mediterranean 166,145­170. seagrass Posidonia oceanica, Marine Ecology Progress Series. 106, 139­146. 24 Craft, C. (2007) Freshwater input structures soil properties, vertical accretion, and nutrient 17 Romero, J, Perez, M., Mateo, M.A., & C-F. (1994) accumulation of Georgia and U.S. tidal marshes. The belowground organs of the Mediterranean seagrass Limnology and Oceanography, 52,1220­1230. Posidonia oceanic as a biogeochemical sink. Aquatic Botany., 47, 13­19. 25 Atwater, B.F., Belknap, D.F. (1980) Tidal-wetland deposits of the Sacramento-San Joaquin Delta, 18 Mateo, M.A., Romero, J., Perez, M., Littler, California. In: Field ME, Bouma AH, Colburn M.M. & Littler, D.S. (1997) Dynamics of Millenary IP, Douglas RG and Ingle JC, editors. Quaternary Organic Deposits resulting from the growth of the depositional environments of the Pacific Coast. Pacific Mediterranean seagrass Posidonia oceanica. Estuarine, Coast Paleogeography Symposium 4. Proceedings of the Coastal and Shelf Science, 44, 103­110. Society of Economic Paleontologists and Mineralogists. Los Angeles (CA): Society of Economic Paleontologists 19 Mateo, M.A., Cebrian, J., Dunton, K. & Mutchler, and Mineralogists. p 89­103. T. (2006) Carbon Fluxes in Seagrass Ecosystems. 50 Environment Department Papers Sources Cited 26 Twilley, R.R., Chen, R.H. and Hargis, T. (1992) the Pelican Cays and Twin Cays ranges, Belize, in Carbon sinks in mangroves and their implications to Lang, M.A., Macintyre, I.G., and Rützler, K., eds., carbon budget tropical coastal ecosystems. Water, Air Proceedings of the Smithsonian Marine Science and Soil Pollution. 64, 265­288. Symposium: Smithsonian Contributions to the Marine Sciences, no. 38, p. 415­427 27 Rojstazcer, S.A. and Deverel, S.J. (1995) Land subsidence in drained histosols and highly organic 34 Middleton B., Devlin, D., Proffitt, E., McKee, K. mineral soils of California. Soil Science Society of & Cretini, K.F. (2008) Characteristics of mangrove America. 59, 1162­1167. swamps managed for mosquito control in eastern Florida. Marine Ecology Progress Series. 371, 117­129 28 Lallier-Verges, E., Perrussel, B.P., Disnar, J-P and Baltzer, F. (1998) Relationship between environmental 35 Fujimoto, K., Imaya, A., Tabuchi, R., Kuramoto, conditions and the diagentic evolution of organic S., Utsugi, H. & Murofushi, T. (2001) Below ground matter derived from higher plants in a modern carbon storage of Micronesian mangrove forests. mangrove swamp system (Guadeloupe, French West Ecological Research, 14, 409­413. Indies). Organic Geochemistry. 29, 1663­1686. 36 Warne, A.G., Meade, R.H., White, W.A., Guevara, 29 Fujimoto, K., Imaya, A., Tabuchi, R., Kuramoto, E.H., Gibeaut, J., Smyth, R.C., Aslan, A. & Tremblay S., Utsugi, H. & Murofushi, T. (2001) Below ground T. (2002) Regional Controls on geomorphology, carbon storage of Micronesian mangrove forests. hydrology and ecosystem integrity of the Orinoco Ecological Research, 14, 409­413. Delta, Venezuela. Geomorphology, 44, 273­307. 30 Warne, A.G., Meade, R.H., White, W.A., Guevara, 37 Takaya, Y. (1974) A physiographic classification of E.H., Gibeaut, J., Smyth, R.C., Aslan, A. & Tremblay rice land in the Mekong Delta. Southeast Asian Studies. T. (2002) Regional Controls on geomorphology, 12, 135­142. hydrology and ecosystem integrity of the Orinoco Delta, Venezuela. Geomorphology, 44, 273­307. 38 Nguyen, H.C. (1993) Pedological Study of the Mekong Delta. Southeast Asian Studies., 31, 158­186. 31 Lovelock, C.E., Feller, I.C., KcKee, K.L., and Thompson, R. (2005). Variation in Mangrove Forest 39 Atwater, B.F., Belknap, D.F. (1980) Tidal-wetland Structure and Sediment Characteristics in Bocas del deposits of the Sacramento-San Joaquin Delta, Toro, Panama. Caribbean Journal of Science, 41, California. In: Field ME, Bouma AH, Colburn 456­464. IP, Douglas RG and Ingle JC, editors. Quaternary depositional environments of the Pacific Coast. Pacific 32 Craft, C.B. and Richardson, C.J. (2008) Soil Coast Paleogeography Symposium 4. Proceedings of the Characteristics of the Everglades Peatland. In: Society of Economic Paleontologists and Mineralogists. Richardson C.J. (ed.) The Everglades Experiments: Los Angeles (CA): Society of Economic Paleontologists Lessons for Ecosystem Restoration. Springer-Verlag, and Mineralogists. p 89­103. New York. 59­72. 40 Drexler, J.Z., de Fontaine, C.S. & Deverel, S.J. 33 McKee, K.L., and Vervaeke, W.C. (2009) Impacts (2009) The legacy of wetland drainage of the remaining of human disturbance on soil erosion potential and peat in the Sacramento ­ San Joaquin Delta, California, habitat stability of mangrove-dominated islands in USA. Wetlands, 29, 372­386. Marine Ecosystem Series 51 Mitigating Climate Change through Restoration and Management of Coastal Wetlands and Near-shore Marine Ecosystems 41 Delft Hydraulics (2006) PEAT-CO2: Assessment 48 Crooks, S. (1996) Sedimentological Controls on of CO2 Emissions form Drained Peatlands in SE Asia. the Geotechnical Properties of Intertidal Saltmarsh and Report R&D Projects Q3943/Q3684/Q4142. Mudflat Deposits. PhD Thesis, University of Reading, U.K. 42 Giani, L., Bashan, Y., Holguin, G. & Strangmann, A. (1996) Characteristics and methanogensis of the 49 Stephens, J.C., Allen, L.H. & Chen, E. (1984) Balandra lagoon mangrove soils, Baja California Sur, Organic Soil Subsidence. In: T.L. Holzer (Ed.) Man- Mexico. Geoderma. 73, 149­160. induced Land Subsidence. Reviews in Engineering Geology. 6, 107­122. 43 McKee, K.L., and Vervaeke, W.C. (2009) Impacts of human disturbance on soil erosion potential and 50 Rojstazcer, S.A. and Deverel, S.J. (1993) Time habitat stability of mangrove-dominated islands in dependence in atmospheric carbon inputs from the Pelican Cays and Twin Cays ranges, Belize, in drainage of organic soils. Geophysical Research Letters Lang, M.A., Macintyre, I.G., and Rützler, K., eds., 20, 1383­1386. Proceedings of the Smithsonian Marine Science Symposium: Smithsonian Contributions to the Marine 51 Holman, I.P. 2009. An Estimate of reserves and Sciences, no. 38, p. 415­427 loss in the East Anglian Fens. Report Commissioned by the RSPB. http://www.rspb.org.uk/Images/ 44 Andrews, J. E., Samways, G., Dennis, P.F. & Fenlandpeatassessment_tcm9­236041.pdf Maher, B.A. (2000) Origin, abundance and storage of organic carbon and sulphur in the Holocene Humber 52 Rojstazcer, S.A. and Deverel, S.J. (1993) Time Estuary: emphasizing human impacts on storage dependence in atmospheric carbon inputs from change. Geological Society, London Special Issue. 2000. drainage of organic soils. Geophysical Research Letters 166,145­170. 20, 1383­1386. 45 Drexler, J.Z., de Fontaine, C.S. & Deverel, S.J. 53 Rojstazcer, S.A. and Deverel, S.J., (1995) Land (2009) The legacy of wetland drainage of the remaining subsidence in drained histosols and highly organic peat in the Sacramento ­ San Joaquin Delta, California, mineral soils of California. Soil Science Society of USA. Wetlands, 29, 372­386. America. 59, 1162­1167., 46 Huang, Y., Sun, W., Zhang, W., Yu, Y., Su, Y. and 54 Deverel, S.J. and Leighton, D.A. (2010). Historic, Song, C. (2009) Marshland conversion to cropland Recent and Future Subsidence, Sacramento ­ San in northeast China from 1950 to 2000 reduced Joaquin Delta, California, USA. San Francisco Estuary the greenhouse effect. Global Change Biology, doi: and Watershed Science, 8­1­23. 10.1111/j.1365­2486.2009.01976.x 55 Fornasiero, A., Gambolati, G., Putti, M., Teatini, P., 47 Andrews, J. E., Samways, G., Dennis, P.F. & Ferraris, S., Pitacco, A., Rizzetto., F., Tosi, L. Bonardi, Maher, B.A. (2000) Origin, abundance and storage of M. & Gatti, P. (2002) Subsidence Due To Peat Soil organic carbon and sulphur in the Holocene Humber Loss in the Zennare Basin (Italy: Design and Set-up of Estuary: emphasizing human impacts on storage the Field Experiment. In: P. Campostrini (ed.) Scientific change. Geological Society, London Special Issue. 2000. Research and Safeguarding of Venice. Instituto Veneto 166,145­170. di Scienze Lettere ed Arti 201­215. Venezia. 52 Environment Department Papers Sources Cited 56 Holman, I.P. 2009. An Estimate of reserves and In R Lal (ed) Encyclopedia of soil science: Volume 1, loss in the East Anglian Fens. Report Commissioned 2nd ed CRC Press, Boca Raton, FL. by the RSPB. http://www.rspb.org.uk/Images/ Fenlandpeatassessment_tcm9­236041.pdf 66 Spalding, M., Kainuma, M., Collins, L. (2010) World atlas of mangroves. ITTO, ISME, FAO, 57 Ingebritsen, S.E., McVoy, C., Glaz, B. & park, UNEP-WCMC, UNESCO-MAB and UNU-INWEH. W. (1999) Florida Everglades: Subsidence threatens Earthscan UK, USA. agriculture and complicates ecosystem restoration. In. D. Galloway et al. (Eds.) Land Subsidence in the 67 Craft, C., Megonigal, P., Broome, S., Stevenson, J., United States. U.S. Geological Survey Circular 1182, Freeze, R,, Cornell, J., Zheng, L., and Sacco, J. (2003). 95­106. The pace of ecosystem development of constructed Spartina alterniflora marshes. Ecological Applications, 58 Wösten, J.H.M., Ismail, A.B. and Van Wijk, 13., 1417­1432. A.L.M. (1997) Peat subsidence and its practical implications: a case study in Malaysia. Geoderma 78, 68 Chmura, G.L., Anisfield, S.C., Cahoon, D.R., pp. 25­36. Lynch, J.C. (2003) Global carbon sequestration in tidal, saline wetland soils. Global Biogeochemical 59 Poffenbarger, H., B Needelman, JP Megonigal Cycles: 1111, doi:10.1029/2002GB001917. (in review). Methane emissions from tidal marshes. Wetlands. 69 Duarte, C.M., Middelburg, J.J., Caraco, N. (2005) Major Role of Marine Vegetation on the Oceanic 60 Megonigal, JP., Schlesinger, WH. (2002) Methane- Carbon Cycle. Biogeosciences 2:1­8. limited methanotrophy in tidal freshwater swamps. Global Biogeochemical Cycles 16(4). 70 Philips Williams & Associates (PWA), Ltd & Science Applications International Corporation 61 Van Der Nat, F.J., Middelburg, J.J. (2000) (SAIC) (2009) Greenhouse Gas Mitigation Methane emission from tidal freshwater marshes. Typology Issues Paper Tidal Wetlands Restoration. Biogeochemistry: 49, 103­121. Prepared for California Climate Action Registry. http://www.climateactionreserve.org/wp-content/ 62 Bange, H.W. (2006) Nitrous oxide and methane in uploads/2009/03/future-protocol-development_tidal- European coastal waters. Estuarine Coastal and Shelf wetlands.pdf Science 70:361­374. 71 Feijtel, T.C., Delaune, R.D., Patrick, W.H. (1985) 63 Jickells, T. (1998) Nutrient Biogeochemistry of the Carbon Flow in Coastal Louisiana. Marine Ecology- Coastal Zone. Science 271(5374):217­222. Progress Series 24(3):255­260. 64 Spalding, M., Kainuma, M., Collins, L. (2010) 72 Miller, R., Fram, M., Fujii, R., Wheeler, G. (2008) World atlas of mangroves. ITTO, ISME, FAO, Subsidence reversal in a re-established wetland in the UNEP-WCMC, UNESCO-MAB and UNU-INWEH. Sacremento-San Joaquin Delta, California, USA. San Earthscan UK, USA. Francisco Estuary & Watersheed Science. Available from: http://repositories.cdlib.org/jmie/sfews/vol6/iss3/ 65 Andriesse, W. & van Mensvoort, M.E.F., (2006). art1. Acid Sulfate Soils: Distribution and Extent. p. 14­19. Marine Ecosystem Series 53 Mitigating Climate Change through Restoration and Management of Coastal Wetlands and Near-shore Marine Ecosystems 73 Poffenbarger, H., B Needelman, JP Megonigal and Its Role in the Global Carbon Cycle. Geophysical (in review). Methane emissions from tidal marshes. Monograph Series, 183, 1­23. Wetlands. 83 Godfrey, H.C.J., Beddington, J.R., Crute, I.R., 74 Miller R, Fram M, Fujii R, Wheeler G. (2008) Haddad, L., Lawrence, D., Muir, J.F., Pretty, J., Subsidence reversal in a re-established wetland in the Robinson, S., Thomas, S.M. & Toulmin, C. (2010) Sacremento-San Joaquin Delta, California, USA. San Food Security: The Challenge of Feeding 9 Billion Francisco Estuary & Watersheed Science.: http:// People. Science 327, 812­817. repositories.cdlib.org/jmie/sfews/vol6/iss3/art1. 84 Harris, R.J., Milbrandt, E.C., Everham III, E.M. 75 Ibid & Bovard, B.D. (2010) the effects of reduced tidal flushing on Mangrove structure and function across 76 Personal Communication: Robin Miller. a disturbance gradient. Estuaries and Coasts. DOI 10.1007/s12237-010-9293-2. 77 Deverel, S.J. and Leighton, D.A. (2010) Historic, Recent and Future Subsidence, Sacramento ­ San 85 www.sws.org/wetland_concerns/docs/restoration.pdf Joaquin Delta, California, USA. San Francisco Estuary and Watershed Science, 8­1­23. 86 Barbier, E.B. (2007) Valuing ecosystem services as productive inputs. Economic Policy 22(01):179­229 78 Craft, C. (2007) Freshwater input structures soil pp. properties, vertical accretion and nutrient accumulation of Georgia and U.S. tidal marshes. 87 Das, S. and Vincent, J.R. 2009. Mangroves protected villages and reduce death toll during Indian 79 Yu, KW., Faulkner, SP., Patrick, WH. (2006) Redox super cyclone. Proceedings of the National Academy of potential characterization and soil greenhouse gas Science 106, 7357­7360. concentration across a hydrological gradient in a Gulf coast forest. Chemosphere 62(6):905­914. 88 UNEP-WCMC (2006) In the front line: shoreline protection and other ecosystem services from 80 Simenstad, C., Reed, D., and Ford, M., (2006) mangroves and coral reefs. UNEP-WCMC, Cambridge, When is restoration not? Incorporating landscape-scale UK 33 pp. processes to restore self-sustaining ecosystems in coastal wetlands. Ecological Engineering. 26, 27­39. 89 Barbier, E.B. (2007) Valuing ecosystem services as productive inputs. Economic Policy 22(01):179­229 81 Crooks, S. and Sharpe J. (2007) California pp. Dreamin' ­ Lessons in Coastal Marsh Restoration from San Francisco Bay. Proceedings of the DEFRA Flood 90 UNEP-WCMC (2006) In the front line: shoreline and Coastal Erosion Risk Management Conference, protection and other ecosystem services from York, UK. mangroves and coral reefs. UNEP-WCMC, Cambridge, UK 33 pp. 82 Sundquist, E.T., Ackerman, K.V., Parker, L. & Huntzinger, D.N. (2009) An introduction to global 91 Barbier, E.B. (2007) Valuing ecosystem services as carbon cycle management. In: Carbon Sequestration productive inputs. Economic Policy 22(01):179­229 pp. 54 Environment Department Papers Sources Cited 92 UNEP (2006) Marine and coastal ecosystems and 101 Spalding, M., Kainuma, M., Collins, L. (2010) human well-being: A synthesis report based on the World atlas of mangroves. ITTO, ISME, FAO, findings of the Millennium Ecosystem Assessment. UNEP-WCMC, UNESCO-MAB and UNU-INWEH. UNEP. 76 pp. Earthscan UK, USA. 93 FAO (2004) The State of World Fisheries. 102 Green, E.P. and Short, F.T. (2003) World atlas of seagrasses. University of California Press, Los Angeles. 94 Hale, L. et al. (2009) Ecosystem-based Adaptation 298 pp. in Marine and Coastal Ecosystems. Renewable Resources Journal 21, 25 (4) 103 Waycott, M et al. (2009) Accelerating loss of seagrass across the globe threatens coastal ecosystems. 95 Convention on Biological Diversity (CBD) PNAS. 106 (30). (2009) Connecting Biodiversity and Climate Change. Mitigation and Adaptation ­ Report of the Second 104 UNEP (2004) Seagrass in the South China Sea. Ad Hoc Technical Expert Group on Biodiversity and UNEP/GEF/SCS Technical Publication No. 3 Climate Change under the Convention on Biological Diversity. Montreal, Technical Series No. 41, 126 pages. 105 Curke, L., Kura, Y., Kassem, K., Revenga, C., https://www.cbd.int/doc/publications/cbd-ts-41-en.pdf Spalding, M. and McAllister, D. (2001) Pilot analysis of global ecosystems: coastal ecosystems. World Resources 96 Spalding, M., Kainuma, M., Collins, L. (2010) Institute. 77 pp. World atlas of mangroves. ITTO, ISME, FAO, UNEP-WCMC, UNESCO-MAB and UNU-INWEH. 106 Heileman and Rabalais 2009. Gulf of Mexico Earthscan UK, USA. LME. In: Sherman, K. and Hempel, G. (Editors) 2009. The UNEP Large Marine Ecosystem Report: 97 Curke, L., Kura, Y., Kassem, K., Revenga, C., A perspective on changing conditions in LMEs of the Spalding, M. and McAllister, D. (2001) Pilot analysis of world's Regional Seas. UNEP Regional Seas Report global ecosystems: coastal ecosystems. World Resources and Studies No. 182. United Nations Environment Institute. 77 pp. Programme. Nairobi, Kenya. 98 Dudley, N., Stolton, S., Belokurov, A., Krueger, 107 Secretariat of the Convention on Biological L., Lopokhine, N., MacKinnon, K., Sandwith, T. and Diversity (2010) Global Biodiversity Outlook 3. Sekhran, N. [eds] (2010) Natural solutions: protected Montreal. 94 pp. areas helping people cope with climate change. IUCN- WCPA, TNA, UNDP, WCS, The World Bank and 108 Saintilan, N. and Rogers, K. (2009) Coastal WWF. Gland, Switzerland, Washington DC and New saltmarsh vulnerability to climate change in SE York USA. 126 pp. Australia. 99 Secretariat of the Convention on Biological 109 Gaden, K.B., Silliman, B.R., and Bertness, M.D. Diversity (2010) Global Biodiversity Outlook 3. (2009) Centuries of human-driven change in salt Montreal. 94 pp. marsh ecosystems. Annual Review Marine Science. 1, 117­141. 100 FAO (2007) The world's mangroves 1980­2005. FAO Forestry Paper 153, Rome. Marine Ecosystem Series 55 Mitigating Climate Change through Restoration and Management of Coastal Wetlands and Near-shore Marine Ecosystems 110 FEMA (1991) Projected Impact of Relative Sea of Terrestrial Sediment to the Global Ocean. Science Level Rise on the National Flood Insurance Program. 308:376­380 Published by Federal Emergency Management Agency, 119 UNEP (2006) Marine and coastal ecosystems Federal Insurance Adminstration. and human well-being: A synthesis report based on the findings of the Millennium Ecosystem Assessment. 111 Philip William and Associates, Ltd. and Science UNEP. 76 pp. Applications International Corporation (2009) Greenhouse Gas Mitigation Typology Issues Paper 120 Syvitski, J.P.M., Kettner, A. J., Overeem, I., Tidal Wetlands Restoration, prepared for the California Hutton, E. W., Hannon, M. T., Brakenridge, G. R., Climate Action Registry. Day, J., Vörösmarty, C., Saito, Y., Giosan, L.,and Nicholls, R.J. (2009) Sinking deltas due to human 112 Yang, S-L and Chen J-Y. (1995) Coastal salt marsh activities. Nature Geoscience. 2, 681­686 and mangrove swamps in China. Chinese Journal of Oceanology and Limnology. 13, 318­324 121 Valiela, I., Bowen J.L., and York J.K. (2001) Mangrove forests: one of the world's threatened major 113 An, S., Li, H., Guan, B., Zhou, C., Wang, Z., tropical environments. Bioscience. 51: 807­815. Deng, Z., Zhi, Y., Xu, C., fang, S., Jiang, J. and Li., H. (2007) China's natural wetlands: past problems, 122 Barbier, E.B. (2007) Valuing ecosystem services current status, and future challenges. Ambio 36, as productive inputs. University of Wyoming. Pp. 335­342. 179­229. 114 Department of Environmental Water and Rivers 123 UNEP (2006) Marine and coastal ecosystems Commission (2002) Draft DEWCP and EPA guidance and human well-being: A synthesis report based on on managing acid sulfate soils. Retrieved from: http:// the findings of the Millennium Ecosystem Assessment. www.wicc.southcoastwa.org.au/reports/ass7/ass7.html UNEP. 76 pp. [Date accessed: 19th August, 2010] 124 Curke, L., Kura, Y., Kassem, K., Revenga, C., 115 UNFPA (2009) State of the World's Population Spalding, M. and McAllister, D. (2001) Pilot analysis of 2009. Facing a changing world: women, population global ecosystems: coastal ecosystems. World Resources and climate. United Nations Population Fund. 104 pp. Institute. 77 pp. 116 Coleman, J.M., Huh, O.K., Braud Jr., D. (2008) 125 Bjork, M., Short, F., Mcleod, E. and Beer, S. Wetland loss in world deltas. Journal of Coastal (2008) Managing segrasses for resilience to climate Research. 24(1A), 1­14. change. IUCN, Gland, Switzerland. 56 pp. 117 Crooks. S. and Turner, R.K., (1999) Integrated 126 Nicholls, R.J. (2004) Coastal flooding and coastal management: sustaining estuarine natural wetland loss in the 21st century: changes under the resources. Advances in Ecological Research. 29, SRES climate and socio-economic scenarios. Global 241­289. Environmental Change 14(1):69­86. 118 Syvitski, J.P.M., Vörösmarty, C.J., Kettner, A.J. 127 Sale, P.F., M.J. Butler IV, A.J. Hooten, J.P. and Green, P. (2005) Impact of Humans on the Flux Kritzer, K.C. Lindeman, Y. J. Sadovy de Mitcheson, 56 Environment Department Papers Sources Cited R.S. Steneck, and H. van Lavieren (2008) Stemming UNREDDProgramme/CountryActions/zambia/ Decline of the Coastal Ocean: Rethinking tabid/1029/language/en-US/Default.aspx Environmental Management, UNU-INWEH, Hamilton, Canada. 135 http://unfccc.int/resource/docs/2010/awglca12/ eng/14.pdf (Page 52) 128 Secretariat of the Convention on Biological Diversity (2010) Global Biodiversity Outlook 3. 136 Yee, M.E. (2010) REDD and BLUE Carbon: Montreal. 94 pp. Carbon Payments for Mangroves Conservation. MAS Marine Biodiversity and Conservation, Capstone Project. 129 Pethick, J.S., 2001. Coastal management and sea level rise. Catena, 42, 307­322. 137 Murray, B.C., Pendleton, L., Jenkins, A., Sifleet, S. with Contributions by Craft, C., Crooks, S., Donato., 130 Crooks, S., The effect of sea level rise on coastal D., Fourqurean, J., Kauffmann, B., Marba, N., geomorphology. Ibis, 146(suppl.1),18­20. Megonigal, P. and Pidgeon E., (2011). Green Payments for Blue carbon: Economic Incentives for Protecting 131 Crooks, S., Emmett-Mattox, S. & Findsen, F. Threatened Coastal Habitats. Report to the Linden (2010) Findings of the National Blue Ribbon Panel on Trust for Conservation. 47pp. the Development of a Greenhouse Gas Offset Protocol for Coastal Wetlands Restoration and Management: 138 Under examination by the Nichols School of Action Plan. Restore America's Estuaries, Philip the Environment at Duke University, Funded by the Williams & Associates, Ltd. and Science Applications Linden Trust Foundation. International Corporation. August, 2010. 139 http://unfccc.int/resource/docs/2010/awg15/eng/ https://www.estuaries.org/images/stories/rae-action- crp04r04.pdf plan-tidal-wetlandsghg-offset-protocol-aug-2010.pdf 140 FCCC/KP/AWG/2009/17 ­ "Wetlands" includes 132 See for example Philips Williams & Associates land that is covered or saturated by water for all or part (PWA), Ltd & Science Applications International of the year, such as peatland, and which does not fall Corporation (SAIC) (2009) Greenhouse Gas under the forest land, cropland, grassland or settlement Mitigation Typology Issues Paper Tidal Wetlands categories. Restoration. Prepared for California Climate Action Registry. http://www.climateactionreserve.org/ 141 http://unfccc.int/resource/docs/2010/awg15/eng/ wp-content/uploads/2009/03/future-protocol- crp04r04.pdf development_tidal-wetlands.pdf 142 http://www.ecosystemsclimate.org/NewsEvents/ 133 http://unfccc.int/files/meetings/cop_16/ Pressreleases/tabid/1617/articleType/ArticleView/ application/pdf/cop16_lca.pdf articleId/2024/Default.aspx 134 Zambia (2010) UN-REDD Programme ­ Zambia 143 EDF Forestry and Land Use Policy Basics Quick Start Initiative. UN Collaborative Programme (LULUCF) June 2010 ­ Summary on Reducing Emissions from deforestation and forest degradation in developing countries national joint 144 EDF Fixing forest and land accounting rules June programme document. http://www.un-redd.org/ 2010 ­ Recommendations Marine Ecosystem Series 57 Mitigating Climate Change through Restoration and Management of Coastal Wetlands and Near-shore Marine Ecosystems 145 Ellis, J., Moarif, S. & Briner, G (2010) Core the Development of a Greenhouse Gas Offset Protocol Elements of national reports. OECD, IEA. http://www. for Coastal Wetlands Restoration and Management: oecd.org/dataoecd/28/32/45409866.pdf Action Plan. Restore America's Estuaries, Philip Williams & Associates, Ltd. and Science Applications 146 Ellis, J., Moarif, S. & Briner, G (2010) Core International Corporation. August, 2010. Elements of national reports. OECD, IEA. http://www. oecd.org/dataoecd/28/32/45409866.pdf 157 Philips Williams & Associates (PWA), Ltd & Science Applications International Corporation 147 http://www.ipcc-nggip.iges.or.jp/public/gpglulucf/ (SAIC) (2009) Greenhouse Gas Mitigation Typology gpglulucf_contents.html Issues Paper Tidal Wetlands Restoration. Prepared for California Climate Action Registry. http://www. 148 Revision of the UNFCCC reporting guidelines climateactionreserve.org/wp-content/uploads/2009/03/ on annual inventories for Parties included in Annex I future-protocol-development_tidal-wetlands.pdf to the Convention. Draft conclusions proposed by the (SBSTA) Chair http://unfccc.int/resource/docs/2010/ 158 Chmura, G.L., Anisfield, S.C., Cahoon, D.R., sbsta/eng/l12.pdf Lynch, J.C. (2003) Global carbon sequestration in tidal, saline wetland soils. Global Biogeochemical 149 http://www.ipcc-nggip.iges.or.jp/public/2006gl/ Cycles: 1111, doi:10.1029/2002GB001917. pdf/4_Volume4/V4_07_Ch7_Wetlands.pdf 159 Nellemann, C., Corcoran, E., Duarte, C.M., 150 Views on issues relating to the 2006 IPCC Valdes, L., DeYoung, C., Fonseca, L., Grimsditch. Guidelines and the revision of the UNFCCC Annex I G. (Eds) (2009) Blue Carbon. A Rapid Response reporting guidelines Submissions from Parties (March Assessment. UNEP, Grid-Arendal, www.grida.no 2010) http://unfccc.int/resource/docs/2010/sbsta/eng/ misc01.pdf 160 Laffoley, D. & Grimsditch, G. (eds) (2009) The management of natural coastal carbon sinks. IUCN, 151 http://www.ipcc-nggip.iges.or.jp/public/gpglulucf/ Gland, Switzerland. 53pp. gpglulucf_contents.html 161 Philips Williams & Associates (PWA), Ltd 152 http://www.ipcc-nggip.iges.or.jp/public/2006gl/ & Science Applications International Corporation pdf/4_Volume4/V4_07_Ch7_Wetlands.pdf (SAIC) (2009) Greenhouse Gas Mitigation Typology Issues Paper Tidal Wetlands Restoration. Prepared 153 http://www.ipcc-nggip.iges.or.jp/public/2006gl/ for California Climate Action Registry. http://www. pdf/4_Volume4/V4_02_Ch2_Generic.pdf climateactionreserve.org/wp-content/uploads/2009/03/ future-protocol-development_tidal-wetlands.pdf 154 http://www.ipcc-nggip.iges.or.jp/public/2006gl/ pdf/4_Volume4/V4_05_Ch5_Cropland.pdf 162 Crooks, S., Emmett-Mattox, S. & Findsen, F. 2010. Findings of the National Blue Ribbon Panel on 155 http://www.ipcc-nggip.iges.or.jp/public/2006gl/ the Development of a Greenhouse Gas Offset Protocol pdf/4_Volume4/V4_07_Ch7_Wetlands.pdf for Coastal Wetlands Restoration and Management: Action Plan. Restore America's Estuaries, Philip 156 Crooks, S., Emmett-Mattox, S. & Findsen, F. Williams & Associates, Ltd. and Science Applications 2010. Findings of the National Blue Ribbon Panel on International Corporation. August, 2010. 58 Environment Department Papers Sources Cited 163 http://www.v-c-s.org/docs/VCS-Program-PRC- for Coastal Wetlands Restoration and Management: Public-Consultation-Document.pdf Action Plan. Restore America's Estuaries, Philip Williams & Associates, Ltd. and Science Applications 164 VCS (2010) VCS Consultation Document: International Corporation. August, 2010. Proposal for Inclusion of Peatland Rewetting and Conservation (PRC) under VCS Agriculture, Forestry 166 http://cmsdata.iucn.org/downloads/carbon_ and Other Land Use (AFOLU) Program. Voluntary managment_report_final_printed_version.pdf Carbon Standards. 19 may, 2010. 167 http://www.grida.no/publications/rr/blue-carbon/ 165 Crooks, S., Emmett-Mattox, S. & Findsen, F. 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