According to a report by the Ministry of Agriculture and Environment, Viet Nam currently has about 168,741 hectares of mangrove forests, accounting for 3% of the country’s total forest area. Carbon stocks within mangrove ecosystems are estimated at around 8.7 million tonnes, with an average storage capacity ranging from 68 to 250 tonnes per hectare—relatively high compared with several other forest ecosystems. Research conducted by scientists at the Mangrove Ecosystem Research Centre (Ha Noi National University of Education) shows that 71% of carbon stocks are stored in the soil, while 29% are contained in above-ground biomass beneath the forest canopy.
Beyond their significant role in mitigating climate change through carbon absorption and storage, mangrove ecosystems also serve as natural shields against storms and tsunamis, helping to minimise damage caused by extreme weather events. They support livelihoods through agricultural and forestry production activities and provide habitats for many rare plant and animal species, contributing greatly to biodiversity conservation.
Viet Nam currently has about 168,741 hectares of mangrove forests, accounting for 3% of the country’s total forest area. Carbon stocks within mangrove ecosystems are estimated at around 8.7 million tonnes, with an average storage capacity ranging from 68 to 250 tonnes per hectare— relatively high compared with several other forest ecosystems.
Notably, as natural carbon “sinks,” mangrove ecosystems hold great potential to generate substantial revenue from the increasingly vibrant carbon credit market. However, research findings also indicate that mangrove forests are facing a decline in area due to human activities (agriculture, aquaculture, construction), natural disasters, and climate change. Meanwhile, for various reasons, conservation and development projects targeting mangrove ecosystems have yet to deliver the expected effectiveness.
Studies by international scientists refer to the carbon stored in mangrove soils and biomass as “blue carbon.” Blue carbon ecosystems convert carbon dioxide into organic biomass through photosynthesis and store it in plant components such as leaves, trunks, and branches. When these components fall, they are retained and accumulate in waterlogged soils. Over many years, carbon builds up beneath thick sediment layers, forming massive carbon stocks that can potentially be tapped for the carbon credit market.
Moreover, blue carbon stored in mangrove ecosystems can be preserved for long periods because thick sediment layers slow down the decomposition of plant matter. Preliminary estimates suggest that globally, more than 21 billion tonnes of carbon dioxide are stored in approximately 15 million hectares of mangrove ecosystems. Meanwhile, mangrove forests account for only about 0.7% of the world’s total forest area. This highlights the enormous volume of carbon stored in the waterlogged soils of these ecosystems.
The challenge, however, lies in determining appropriate methodologies for calculating carbon stocks and converting them into tradable credits so that mangrove carbon can effectively enter the market. According to Associate Professor Dr Le Xuan Tuan of the Mangrove Ecosystem Research Centre, there are currently two methods for estimating carbon stocks in mangrove ecosystems: direct field measurement (sampling trees, measuring key parameters, and calculating biomass using regression equations) and indirect methods (using models and remote sensing technologies to analyse data and estimate biomass over forest areas).
Dr Tuan noted that there are five carbon “pools” in mangrove ecosystems: woody biomass; shrubs and live ground vegetation; dead organic matter; below-ground biomass; and soil carbon. Carbon stock calculations can be based on laboratory analysis results, after which carbon (CO2) values are multiplied by 3.667 to convert them into carbon dioxide (CO2). With estimated reserves of around 8.7 million tonnes, this represents a significant figure amid global carbon scarcity and increasingly stringent emission reduction regulations.
Recognising both the importance of and threats to coastal mangrove forests, on October 4, 2021, the Prime Minister issued Decision No. 1662/QD-TTg approving the Project on the Protection and Development of Coastal Forests to Respond to Climate Change and Promote Green Growth for the 2021–2030 period. Under this project, the Institute of Forest Ecology and Environment (Viet Nam National University of Forestry) was tasked with, and has implemented, numerous activities to develop methodologies for calculating, measuring, and monitoring carbon stocks in mangrove ecosystems.
This research provided the basis for the Department of Forestry (under the Ministry of Agriculture and Environment) to issue Decision No.316/QD-LN-SXLN on April 29, 2024, promulgating Technical Guidelines for Determining Biomass and Carbon Stocks in Mangrove Forests. These guidelines serve as a “compass” enabling Viet Nam’s coastal localities to effectively harness carbon credits from mangrove ecosystems.
However, these are only initial research results and data collected by research teams. To accurately determine carbon stocks and properly value the economic worth of mangrove carbon credits, broader survey programs are needed, incorporating advanced scientific and technological applications such as artificial intelligence (AI), remote sensing, and the Internet of Things (IoT).
In addition, policy-implementing agencies need to promptly issue regulatory documents, develop supplementary technical guidelines for analysing total organic carbon in water and sediments, strengthen the protection and restoration of mangrove ecosystems, and enhance international cooperation in surveying and assessing mangrove carbon stocks worldwide.
