Because of their unique biodiversity and inordinately large carbon stocks, tropical peat forests are considered key wetland ecosystems for conservation and restoration. Despite this recognition continued deforestation and land cover change result in these ecosystems becoming significant sources of greenhouse gases. There is a strong need for accurate quantification of carbon stocks and emissions at scales relevant for participation in carbon markets and nationally determined contributions. Based upon analyses of 125 forests in 4 continents (Asia, Oceania, the Americas) there was a broad range in peat depths (19–1414 cm) with total ecosystem carbon stocks (TECS) ranging from 172 to 9379 Mg C ha−1 (mean of 2137 Mg C ha−1). Among the 47 sampled sites known to be tidally-influenced (i.e., blue carbon ecosystems), TECS ranged from 206 to 5591 Mg C ha−1 with a mean of 1979 Mg C ha−1. Those sites with deep peats (> 7 m depth) have a mean TECS of 4620 ± 395 Mg C ha−1 and we know of no ecosystems with an equivalent ecosystem carbon stock. Peat soils composed a mean of 86 % of TECS, and peat depths were strongly correlated with soil carbon stocks at continental and global scales (R2 > 0.80) suggesting inventories that include measurement of peat depth can accurately estimate carbon stocks. Degradation of peat landscapes comes with high ecological and social costs including the largest greenhouse gas emissions from any forest land use globally. The social carbon costs to future generations associated with the conversion of tropical peat forests to oil palm plantations is conservatively estimated to be nine times the value of the palm oil generated from the conversion. Such costs and values of the tropical peat forests underscore the importance of the conservation and restoration of these wetlands for future generations – an important element of sustainability.
Tag: blue carbon
Global relationship between upwelling intensities and mangrove distribution and area
Mangroves are essential coastal ecosystems distributed across tropical and subtropical regions, typically found at the confluence of river systems and the sea. Although air temperature has long been recognised as a key determinant of mangrove distribution, upwelling systems that transport cold, nutrient-rich waters from the deep ocean to the surface can also impede mangrove propagule dispersion. However, global studies that examine the influence of upwelling on mangrove distribution remain scarce. In this study, our objective was to investigate the relationship between upwelling systems and global mangrove distribution, with an emphasis on range limits and area extent. We adopted a novel multi-scale approach by analysing mangrove areas at several minimum size thresholds (≥5 ha, ≥50 ha, ≥100 ha, ≥200 ha, and ≥ 300 ha) to evaluate the scale dependence of upwelling effects. Our regression models revealed a clear trend: the coefficient of determination (R2) increased from 0.20 for patches ≥5 ha to 0.37 for ≥50 ha, 0.43 for ≥100 ha, 0.49 for ≥200 ha, and reached 0.53 for patches ≥300 ha. Furthermore, low-upwelling regions harbour 47.7 % of the total mangrove area (66,763 km2), whereas high-upwelling regions account for only 0.5 % (2642 km2). We also found that the highest upwelling intensities occur exclusively in the Atlantic East Pacific mangrove region, a key environmental contrast to the Indo-West Pacific. In conclusion, our study demonstrates that upwelling systems are one factor shaping global mangrove distribution in a strongly scale-dependent manner, with larger, contiguous patches exhibiting a markedly stronger response. These insights emphasise the need to incorporate upwelling intensity and spatial scale into global mangrove conservation and management strategies. This integration is essential to address the complex interplay of environmental factors under shifting oceanographic and climatic conditions.
Carbon pricing: Approaches, lessons and recommendations for blue carbon in Vietnam
Vietnam possesses significant potential for blue carbon development, offering opportunities for climate mitigation, biodiversity conservation and sustainable economic growth. This report examines the critical role of carbon pricing mechanisms in unlocking this potential, focusing on both compliance and voluntary carbon markets.
Vietnam blue carbon opportunity assessment
Marine and coastal ecosystems, including mangroves and seagrass meadows, are global hotspots for “blue carbon” storage in vegetation and soils, but face mounting pressure from human activities and climate change. Mechanisms that mobilize foreign direct investment to reduce anthropogenic greenhouse gas emissions and enhance sustainable development, such as voluntary carbon projects, offer financing that can complement government efforts. We assessed blue carbon opportunities in Vietnam focusing on mangroves and seagrass in the Mekong Delta coastal provinces (Kien Giang, Ca Mau, Bac Lieu, Soc Trang, Tra Vinh, Ben Tre and Tien Giang). Object-based image analysis was used to quantify changes in the extent of mangroves from 2016 – 2024. To assess fluctuations in seagrass meadow areas we projected historical changes in seagrass coverage reported in the literature. Emissions of CO2 resulting from changes in mangrove forest and seagrass meadow coverages were estimated using literature-based emission factors. Overall, mangrove coverage in the Mekong Delta coastal provinces declined between 2016 and 2024, despite areas of mangrove expansion. CO2 removals from mangrove area increase did not offset CO2 emissions from mangrove loss during 2016–2024. Our analysis revealed substantial losses in some areas, highlighting the complex dynamics of mangrove conservation. The total net impact of mangrove loss and reforestation in the seven provinces during this period was 14.5 million Mg CO2, with Ca Mau province contributing 77% of emissions. The magnitude of potential CO2 emissions from seagrass loss was smaller, at 31.4 thousand Mg CO2, concentrated in the area of Phu Quoc Island in Kien Giang province. Our results emphasize the need to avoid continued conversion of mangroves, despite gains in mangrove forest areas.
Species-Poor Mangrove Forests also Provide Rich Ecosystem Goods and Services
Mangrove forests provide a wide range of services to coastal communities worldwide. These services include carbon sequestration and coastal protection, both of which are critical in the context of climate change. However, these wetlands are still experiencing destructive anthropogenic impacts in many areas. Senegal and Colombia, two countries in the Atlantic-East Pacific biogeographic region, both have abundant mangrove cover and share several mangrove species. This study assessed the use of mangrove resources (fuelwood, timber, and other non-timber forest products) by local communities in both countries. A total of 210 semi-structured ethnobotanical questionnaire-based interviews were conducted in Sokone and neighboring villages bordering the Sine-Saloum Delta in Senegal (110) and in the Cispata lagoon system in Colombia (100). The results for Senegal indicate that individuals residing near the Sine-Saloum Delta in neighboring villages rely more on mangroves compared to those living in Sokone. In Colombia, reliance on mangroves was associated with occupational activities. Despite lower species diversity compared to the Indo-West Pacific biogeographic region, mangroves provide various services in both areas, underscoring their significance to local communities and their livelihoods. Finally, the Indigenous and local knowledge emphasizes the need for alternatives to mangrove resources and the promotion of sustainable harvesting practices to ensure the conservation of mangroves and the continued provision of essential services.