Wetlands can also produce powerful greenhouse gases such as nitrous oxide and methane and the balance between sequestration and emission is an issue that must be quantified and addressed. The clearing or drainage of wetlands for agriculture or urbanization disturbs the natural balance of carbon cycling in these systems and can lead to large losses of stored organic carbon to atmospheric carbon dioxide.
Such is the importance of wetlands in various aspects of ecosystem function that the Ramsar Convention on wetlands, which came into effect in 1975, is the only global environmental treaty that deals with a single particular ecosystem. Member countries of the Ramsar Convention cover all geographic regions of the planet. The Ramsar Convention on wetlands recognizes five principal types of wetlands: marine wetlands, estuarine wetlands, lacustrine wetlands, riverine wetlands and palustrine wetlands.
The IPCC wetlands supplement (2014) recognizes eight categories of wetlands for preparing inventories of GHG emissions: Peatlands and organic soils; Peatland managed for peat production; Rice cultivation; Coastal wetlands; Inland wetland mineral soils (IWMS); Saline inland wetlands; Constructed wetlands for wastewater treatment and Permanently flooded lands.
The relation of wetlands to climate becomes apparent in this study and the carbon sequestration in different types of wetlands is presented. mehr
Wetlands play an important role in landscape function, including cycling of carbon, water and nutrients, food and fibre production, water purification, regulation of flows, provision of habitats, and tourism and recreation services.
The role of wetlands in carbon sequestration and storage has generally been under-estimated. Wetlands cover approximately six to nine per cent of the Earth’s surface and contain about 35 per cent of global terrestrial carbon. As wetlands are centres of high productivity in the landscape, they have a high capacity to sequester and store carbon. Clearing or drainage of wetlands can lead to large losses of stored organic carbon to atmospheric carbon dioxide.
Greater consideration needs to be given to the roles of wetlands as carbon sources, sinks and storages, when designing climate protection and natural resource programs. Information on the functions of specific types of Australian wetlands is required, to enable better evaluation of their contribution to climate change mitigation and adaptation and to assist in design of programs for their protection, enhancement and restoration for multiple benefits.
A guide on methodological work on wetlands focusing on rewetting and restoration of peatland. mehr
The Wetlands Supplement was developed in accordance with the "Procedures for the preparation, review, acceptance, adoption, approval and publication of IPCC Reports" and the decision at the 35th Session of the IPCC. Review is an essential part of the IPCC process to ensure objective and complete assessment of the current information. In the course of the multi-stage review process - first by experts and then by governments and experts - both expert reviewers and governments are invited to comment on the accuracy and completeness of the scientific/technical/socio-economic content and the overall balance of the drafts.
This study aims on estimating the amount of carbon which is stored in salt marshes and mangrove swamps. mehr
A study on compiled data for 154 sites in mangroves and salt marshes from the western and eastern Atlantic and Pacific coasts, as well as the Indian Ocean, Mediterranean Ocean, and Gulf of Mexico. Results showed that the combined wetlands store at least 44.6 Tg C yr1 and probably more, as detailed areal inventories are not available for salt marshes in China and South America. Much attention has been given to the role of freshwater wetlands, particularly northern peatlands, as carbon sinks. In contrast to peatlands, salt marshes and mangroves release negligible amounts of greenhouse gases and store more carbon per unit area.
A study to quantify the soil carbon storage and sequestration rates of undisturbed natural wetlands and disturbed wetlands in an Australian estuary. mehr
Disturbed and undisturbed estuarine wetlands of the Hunter estuary, New South Wales, Australia were selected as the study sites for this research. Vertical accretion rates of estuarine substrates were combined with soil carbon concentrations and bulk densities to determine the carbon store and carbon sequestration rates of the substrates tested. Relationships between estuary water level, soil evolution and vertical accretion were also examined.
The carbon sequestration rate of undisturbed wetlands was lower (15% for mangrove and 55% for saltmarsh) than disturbed wetlands, but the carbon store was higher (65% for mangrove and 60% for saltmarsh). The increased carbon sequestration rate of the disturbed wetlands was driven by substantially higher rates of vertical accretion (95% for mangrove and 345% for saltmarsh). Estuarine wetland carbon stores were estimated at 700–1000 Gg C for the Hunter estuary and 3900–5600 Gg C for New South Wales. Vertical accretion and carbon sequestration rates of estuarine wetlands in the Hunter are at the lower end of the range reported in the literature. The comparatively high carbon sequestration rates reported for the disturbed wetlands in this study indicate that wetland rehabilitation has positive benefits for regulation of atmospheric carbon concentrations, in addition to more broadly accepted ecosystem services.
A study on the effects of salinity on C, N, and P storage and accumulation in soils of salt, brackish, and tidal freshwater marshes in river-dominated estuaries of the Georgia coast, USA. mehr
Soil organic C, N, and P were measured in salt, brackish, and tidal freshwater marshes in river-dominated estuaries (Ogeechee, Altamaha, and Satilla) of the Georgia coast to evaluate the effects of salinity on C, N, and P storage and accumulation. Tidal freshwater marshes had greater concentrations of organic C (10.81% w/w) and N (0.71% w/w) than brackish (7.71% C, 0.50% N) or salt (5.95% C, 0.35% N) marshes. Soil accretion rates of 137Cs were greater in tidal freshwater (4.78 mm yr−1) and brackish marshes (4.41 mm yr−1) than in salt marshes (1.91 mm yr−1). Consequently, organic C and N accumulation was greater in tidal freshwater (124 and 8.2 g m−2 yr−1) and brackish (93 and 6.5 g m−2 yr−1) marshes than salt marshes (40 and 2.4 g m−2 yr−1).
Phosphorus accumulation was greater in the brackish marshes. Lower salinity tidal freshwater and brackish marshes remove more C, N, and P; however, salt marshes dominate the spatial extent of the study area (60%) vs. brackish (33%) and tidal freshwater marshes (7%). Combining measurements of C, N, and P accumulation with tidal marsh area, we estimated that tidal freshwater, brackish, and salt marshes stored or removed the equivalent of 2 to 20% of watershed N inputs entering the estuaries from the terrestrial landscape. After accounting for N2 fixation and denitrification, tidal marshes collectively removed the equivalent of 13 to 32% of the N entering estuaries. Tidal marshes, especially tidal freshwater and brackish marshes, are important for improving water quality and decreasing the impacts of N eutrophication of estuarine ecosystems.
In this study the carbon storage of the Caimpugan peatland is calculated and the significance of the soil as a carbon sink becomes apparent. mehr
Globally, peatlands have a high potential in mitigating climate change, but no study has been done on this in the Philippines. This study estimated the amount of stored carbon (C) in the Caimpugan peatland, Agusan Marsh. In Tall Pole Forest, Intermediate Forest, and the Pygmy Forests in two locations in the peatland, the aboveground C stocks were measured in standing trees, understorey, herbaceous vegetation, and litter. In addition, belowground C stocks were also measured in peat soils at different horizons. Non-destructive sampling was done for trees > 5 cm dbh using allometric equations. Total soil organic C was determined using Flash Elemental Analyzer 1112 Series Carbon Analyzer. A two-way ANOVA was used to compare estimated stored C among selected vegetation types with location as the replication.
The estimated aboveground C stock of Caimpugan peatland was 22.9 M t of C within its 5, 487 ha area with an estimated 3,000-6,000 t of C per hectare. The estimated mean belowground C stock (4,659 t C ha- ¹) was much higher than the mean aboveground C stock (53 tC ha- ¹). With the substantial amount of stored C in Caimpugan peatland, its protection is fundamental to enhance its role in mitigating CO2 emissions.
This study addresses the impact of climate change on peatlands. mehr
Boreal and subarctic peatlands comprise a carbon pool of 455 Pg that has accumulated during the postglacial period at an average net rate of 0.096 Pg/yr (1 Pg = 1015 g). Using Clymo's (1984) model, the current rate is estimated at 0.076 Pg/yr. Long- term drainage of these peatlands is estimated to be causing the oxidation to CO2 of a little more than 0.0085 Pg/yr, with combustion of fuel peat adding st0.026 Pg/yr. Emissions of CH4 are estimated to release n0.046 Pg of carbon annually. Uncertainties beset estimates of both stocks and fluxes, particularly with regard to Soviet peatlands.
The influence of water table alterations upon fluxes of both CO2 and CH4 is in great need of investigation over a wide range of peatland environments, especially in regions where permafrost melting, thermokarst erosion, and the development of thaw lakes are likely results of climatic warming. The role of fire in the carbon cycle of peatlands also deserves increased attention. Finally, satellite-monitoring of the abundance of open water in the peatlands of the West Siberian Plain and the Hudson/James Bay Lowland is suggested as a likely method of detecting early effects of climatic warming upon boreal and subarctic peatlands.
Climate change is expected to influence peatlands and its carbon sequestration by changing temperatures and precipitation. mehr
Northern peatlands occupy approximately 4% of the global land surface and store about 30% of the global soil carbon (C). A compilation of C accumulation rates in northern peatlands indicated a long-term average rate of C accumulation of 24.1 g m2 year1. However, several studies have indicated that on a short-time scale and given the proper conditions, these ecosystems can exhibit very high rates of C accumulation (up to 425 g m2 year1).
Peatland development is related to precipitation and temperature, and climate change is expected to have an important impact on the C balance of this ecosystem. Given the expected climate change, we suggest that most of the northern forested peatlands located in areas where precipitation is expected to increase (eastern Canada, Alaska, FSU, and Fennoscandia) will continue to act as a C sink in the future. In contrast, forested peatlands of western and central Canada, where precipitation is predicted to decrease, should have a reduction in their C sequestration rates and (or) could become a C source.
These trends could be affected by forest management in forested peatlands and by changes in fire cycles. Careful logging, as opposed to wildfire, will facilitate C sequestration in forested peatlands and boreal forest stands prone to paludification while silvicultural treatments (e.g., drainage, site preparation) recommended to increase site productivity will enhance C losses from the soil, but this loss could be compensated by an increase in C storage in tree biomass.
Restoration of vegetation and ecosystem function in cutaway peatland by reintroducing Sphagnum fragments gives promising results. mehr
The reintroduction of Sphagnum fragments has been found to be a promising method for restoring mire vegetation in a cutaway peatland. Although it is known that moisture controls Sphagnum photosynthesis, information concerning the sensitivity of carbon dynamics on water-level variation is still scarce.
In a 4-year field experiment, the carbon dynamics of reintroduced Sphagnum angustifolium material in a restored (rewetted) cutaway peatland were studied. Cutaway peatland restored by Sphagnum reintroduction showed high sensitivity to variation in water level. Water level controlled both photosynthesis and respiration. Gross photosynthesis (PG) had a unimodal response to water-level variation with optimum level at −12 cm. The range of water level for high PG (above 60% of the maximum light-saturated PG) was between 22 and 1 cm below soil surface. Water level had a dual effect on total respiration. When the water level was below soil surface, peat respiration increased rapidly along the lowering water level until the respiration rate started to slow down at approximately −30 cm.
Contrary to peat respiration, the response of Sphagnum respiration to water-level variation resembled that of photosynthesis with an optimum at −12 cm. In optimal conditions, Sphagnum reintroduction turned the cutaway site from carbon source to a sink of 23 g C/m2 per season (mid-May to the end of September). In dry conditions, lowered photosynthesis together with the higher peat respiration led to a net loss of 56 g C/m2. Although the water level above the optimum amplitude restricted CO2fixation, a decrease in peat respiration led to a positive CO2balance of 9 g C/m2.
North American prairie pothole wetlands are important carbon stores that can be used in wetland restoration and conservation measures to mitigate greenhouse gas emissions. mehr
North American prairie pothole wetlands are known to be important carbon stores. As a result there is interest in using wetland restoration and conservation programs to mitigate the effects of increasing greenhouse gas concentration in the atmosphere.
However, the same conditions which cause these systems to accumulate organic carbon also produce the conditions under which methanogenesis can occur. As a result prairie pothole wetlands are potential hotspots for methane emissions. The change in soil organic carbon density was examined as well as emissions of methane and nitrous oxide in newly restored, long-term restored, and reference wetlands across the Canadian prairies to determine the net GHG mitigation potential associated with wetland restoration.
The results indicate that methane emissions from seasonal, semi-permanent, and permanent prairie pothole wetlands are quite high while nitrous oxide emissions from these sites are fairly low. Increases in soil organic carbon between newly restored and long-term restored wetlands supports the conclusion that restored wetlands sequester organic carbon. Assuming a sequestration duration of 33 years and a return to historical SOC densities a mean annual sequestration rate for restored wetlands of 2.7 Mg C ha−1year−1 or 9.9 Mg CO2 eq. ha−1 year−1 was estimated. Even after accounting for increased CH4 emissions associated with restoration our research indicates that wetland restoration would sequester approximately 3.25 Mg CO2 eq. ha−1year−1.
This research indicates that widescale restoration of seasonal, semi-permanent, and permanent wetlands in the Canadian prairies could help mitigate GHG emissions in the near term until a more viable long-term solution to increasing atmospheric concentrations of GHGs can be found.
This report includes many information on carbon sequestration of wetlands and tries to link the subject wetlands to the Kyoto Protocol. mehr
The paper describes human settlement and activities that have an impact on prairie wetlands, and gives an overview of carbon sequestration potential in wetlands and related upland areas in the Central Plains, including techniques available for measuring carbon cycling. A final section describes scientific and policy issues that must be taken into account in any effort to see wetlands included in the Kyoto Protocol. This document does not propose policy options for achieving wetland creation and restoration, but it acknowledges that such policies are critical to wetland conservation initiatives.
A 6 year analysis of total carbon balance of an almost intact Atlantic blanket bog in Glencar, County Kerry, Ireland. mehr
Although northern peatlands cover only 3% of the land surface, their thick peat deposits contain an estimated one-third of the world's soil organic carbon (SOC). Under a changing climate the potential of peatlands to continue sequestering carbon is unknown. This paper presents an analysis of 6 years of total carbon balance of an almost intact Atlantic blanket bog in Glencar, County Kerry, Ireland.
The three components of the measured carbon balance were: the land-atmosphere fluxes of carbon dioxide (CO2) and methane (CH4) and the flux of dissolved organic carbon (DOC) exported in a stream draining the peatland. The 6 years C balance was computed from 6 years (2003–2008) of measurements of meteorological and eddy-covariance CO2 fluxes, periodic chamber measurements of CH4 fluxes over 3.5 years, and 2 years of continuous DOC flux measurements. Over the 6 years, the mean annual carbon was −29.7±30.6 (±1 SD) g C m−2 yr−1 with its components as follows: carbon in CO2 was a sink of −47.8±30.0 g C m−2 yr−1; carbon in CH4 was a source of 4.1±0.5 g C m−2 yr−1 and the carbon exported as stream DOC was a source of 14.0±1.6 g C m−2 yr−1. For 2 out of the 6 years, the site was a source of carbon with the sum of CH4 and DOC flux exceeding the carbon sequestered as CO2. The average C balance for the 6 years corresponds to an average annual growth rate of the peatland surface of 1.3 mm yr−1.
A study on the balance between carbon sequestration and green house gas emissions in wetlands. mehr
Wetland ecosystems provide an optimum natural environment for the sequestration and long-term storage of carbon dioxide (CO2) from the atmosphere, yet are natural sources of greenhouse gases emissions, especially methane. It is illustrated that most wetlands, when carbon sequestration is compared to methane emissions, do not have 25 times more CO2 sequestration than methane emissions; therefore, to many landscape managers and non specialists, most wetlands would be considered by some to be sources of climate warming or net radiative forcing.
It is shown by dynamic modeling of carbon flux results from seven detailed studies of temperate and tropical wetlands and from 14 other wetland studies that methane emissions become unimportant within 300 years compared to carbon sequestration in wetlands. Within that time frame or less, most wetlands become both net carbon and radiative sinks.
Furthermore, it is estimated that the world’s wetlands, despite being only about 5–8 % of the terrestrial landscape, may currently be net carbon sinks of about 830 Tg/year of carbon with an average of 118 g-C m−2 year−1 of net carbon retention. Most of that carbon retention occurs in tropical/subtropical wetlands. It is demonstrated that almost all wetlands are net radiative sinks when balancing carbon sequestration and methane emissions and conclude that wetlands can be created and restored to provide C sequestration and other ecosystem services without great concern of creating net radiative sources on the climate due to methane emissions.
Climate is a fundamental driver in tropical wetlands, influencing hydrology and carbon dynamics which could shift and influence carbon storage due to climate change. mehr
This paper summarizes the importance of climate on tropical wetlands. Regional hydrology and carbon dynamics in many of these wetlands could shift with dramatic changes in these major carbon storages if the inter-tropical convergence zone (ITCZ) were to change in its annual patterns.
The importance of seasonal pulsing hydrology on many tropical wetlands, which can be caused by watershed activities, orographic features, or monsoonal pulses from the ITCZ, is illustrated by both annual and 30-year patterns of hydrology in the Okavango Delta in southern Africa. Current studies on carbon biogeochemistry in Central America are attempting to determine the rates of carbon sequestration in tropical wetlands compared to temperate wetlands and the effects of hydrologic conditions on methane generation in these wetlands.
Using the same field and lab techniques, it was estimated that a humid tropical wetland in Costa Rica accumulated 255 g C m year in the past 42 years, 80% more than a similar temperate wetland in Ohio that accumulated 142 g C m year over the same period. Methane emissions averaged 1,080 mg-C m day in a seasonally pulsed wetland in western Costa Rica, a rate higher than methane emission rates measured over the same period from humid tropic wetlands in eastern Costa Rica (120-278 mg-C m day).
Tropical wetlands are often tuned to seasonal pulses of water caused by the seasonal movement of the ITCZ and are the most likely to be have higher fire frequency and changed methane emissions and carbon oxidation if the ITCZ were to change even slightly.
Organic matter origin and transformation in wetland soils from semi-arid wetlands in Central Spain is influenced by dominant vegetation and fire. mehr
Wetland soils from a Mediterranean semiarid wetland (Las Tablas de Daimiel, Central Spain) were studied to characterize the organic matter (OM) and determine its origin and transformation. Cross polarization magic angle spinning (CPMAS) 13C nuclear magnetic resonance (NMR) spectroscopy and mathematical molecular mixing allowed analysis of the organic fraction in terms of six generic components (carbohydrate, protein, lignin, lipid, char and “carbonyl”).
Las Tablas is an active carbon sink, with total organic carbon (TOC) content independent of soil OM quality; the TOC content of the upper sediment is 10.0 ± 7.8%. The inorganic carbon content is also high (5.4 ± 3.3%) and is associated mainly with OM of aliphatic character. The OM composition is variable; samples predominantly aliphatic (carbohydrate, lipid and protein) are characteristic of the northern sector, whereas predominantly aromatic samples are typical of the southern Tablas. A strong negative relationship between protein content and lignin content was found, interpreted as a consequence of different proportions of vascular vs. non-vascular (mostly charophyte) litter input.
The effect of perturbations is apparent in the extended presence of char, particularly abundant in fire-prone areas. OM quantity and quality do not seem to depend on hydrology (although seasonal flooding is associated with less organic wetland soils) or soil characteristics. Dominant vegetation and fire are the main drivers of OM content and composition. Structural carbohydrate, protein and lipid (> 60% of total organic fraction) dominate. Widespread anaerobic conditions and the recent character of the sediments could explain the preservation of different fractions of the original detritus composition (due to different vegetation and presence of microbes).
Combining allometric models and tree ring analysis to estimate carbon stocks and sequestration in aboveground wood biomass of wetland forests in the Pantanal, South America. mehr
In this study allometric models are used combined with tree ring analysis to estimate carbon stocks and sequestration in the aboveground coarse wood biomass (AGWB) of wetland forests in the Pantanal, located in central South America.
In four 1-ha plots in stands characterized by the pioneer tree species Vochysia divergens Pohl (Vochysiaceae) forest inventories (trees ≥10 cm diameter at breast height, D) have been performed and converted to estimates of AGWB by two allometric models using three independent parameters (D, tree height H and wood density ρ). A propagation of measurement errors is performed to estimate uncertainties in the estimates of AGWB. Carbon stocks of AGWB vary from 7.8 ± 1.5 to 97.2 ± 14.4 Mg C ha-1 between the four stands.
From models relating tree ages determined by dendrochronological techniques to C-stocks in AGWB we derived estimates for C-sequestration which differs from 0.50 ± 0.03 to 3.34 ± 0.31 Mg C ha-1 yr-1. Maps based on geostatistic techniques indicate the heterogeneous spatial distribution of tree ages and C-stocks of the four studied stands. This distribution is the result of forest dynamics due to the colonizing and retreating of V. divergens and other species associated with pluriannual wet and dry episodes in the Pantanal, respectively. Such information is essential for the management of the cultural landscape of the Pantanal wetlands.
A comparative study on carbon sequestration and methane emissions from wetlands. mehr
Carbon fixation under wetland anaerobic soil conditions provides unique conditions for long-term storage of carbon into histosols. However, this carbon sequestration process is intimately linked to methane emission from wetlands. The potential contribution of this emitted methane to the greenhouse effect can be mitigated by the removal of atmospheric CO2 and storage into peat.
The balance of CH4and CO2 exchange can provide an index of a wetland's greenhouse gas (carbon) contribution to the atmosphere. Here, the atmospheric global warming potential of methane (GWPM) is related with annual methane emission/carbon dioxide exchange ratio of wetlands ranging from the boreal zone to the near-subtropics. This relationship permits one to determine the greenhouse carbon balance of wetlands by their contribution to or attenuation of the greenhouse effect via CH4 emission or CO2 sink, respectively.
Annual measurements of the relationship between methane emission and net carbon fixation in three wetland ecosystems are reported. The ratio of methane released to annual net carbon fixed varies from 0.05 to 0.20 on a molar basis. Although these wetlands function as a sink for CO2, the 21.8-fold greater infrared absorptivity of CH4 relative to CO2(GWPM) over a relatively short time horizon (20 years) would indicate that the release of methane still contributes to the overall greenhouse effect. As GWPM decreases over longer time horizons (100 years), the analyses suggest that the subtropical and temperate wetlands attenuate global warming, and northern wetlands may be perched on the “greenhouse compensation” point. Considering a 500-year time horizon, these wetlands can be regarded as sinks for greenhouse gas warming potential, and thus attenuate the greenhouse warming of the atmosphere.
Wetlands are not only efficient at accumulating C, but also nitrogen (N) when production exceeds N demand. The high capacity of wetlands to store C and N is partly due to their high productivity and low soil decomposition rates. mehr
Riverine wetlands are created and transformed by geomorphological processes that determine their vegetation composition, primary production and soil accretion, all of which are likely to influence C stocks. Here, we compared ecosystem C stocks (trees, soil and downed wood) and soil N stocks of different types of riverine wetlands (marsh, peat swamp forest and mangroves) whose distribution spans from an environment dominated by river forces to an estuarine environment dominated by coastal processes. We also estimated soil C sequestration rates of mangroves on the basis of soil C accumulation. We predicted that C stocks in mangroves and peat swamps would be larger than marshes, and that C, N stocks and C sequestration rates would be larger in the upper compared to the lower estuary.
Wetland soils are the largest terrestrial pool of carbon, storing approximately 500-700 Gt globally. mehr
Given the rising concentration of carbon dioxide (CO2) in the Earth’s atmosphere, it is important to assess the natural reservoirs in which carbon can be stored. Great Lakes coastal wetlands are a potentially significant pool of carbon that have yet to be thoroughly investigated. The study measured soil C (carbon) and depth of organic matter in swamp, transitional, and wet meadow vegetation zones of three wetlands located in the Eastern half of Michigan’s Upper Peninsula, in the Les Chenaux Islands.
Wetlands contain intrinsic and aesthetic values, they also offer more tangible ecosystem services such as wildlife habitat, biological diversity, soil loss reduction, groundwater recharge, nutrient and toxics filtration, carbon sequestration, and flood water storage. mehr
Major regional wetland losses have occurred across the conterminous U.S. over the last 200+ years with expanding coastal development, agricultural land conversion, and urbanization. Wetlands also have the ability to store atmospheric carbon. Potentially restorable wetlands, by banking additional stored carbon, can make a significant contribution to climate change mitigation. Cultivated wetlands lose their stored soil organic carbon to the atmosphere, but soil organic carbon is rapidly restored when wetland function is restored.
This study compares six temperate wetland communities in Ohio that belong to two distinct hydrogeomorphic types. mehr
High productivity and waterlogged conditions make many freshwater wetlands significant carbon sinks. Most wetland carbon studies focus on boreal peatlands, however, with less attention paid to other climates and to the effects of hydrogeomorphic settings and the importance of wetland vegetation communities on carbon sequestration. Three cores were extracted in each community and analyzed for total carbon content to determine the soil carbon pool.
The amount of carbon that a wetland stores and emits every year depends greatly on the hydrogeochemical characteristics of the ecosystem, which, in turn, determine the wetland vegetation communities. Therefore, to estimate with precision a wetland’s carbon pool and carbon sequestration capacity, it would be more accurate to differentiate between wetland types, especially if wetlands are to be used as a carbon–sequestering systems to reduce net greenhouse gas emissions.