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Building Blue Carbon Projects
An Introductory Guide
8.5
Exploring Seagrass Climate Change Mitigation Potential in Thailand and Australia
One of the key Blue Carbon knowledge gaps for seagrass ecosystems is that the current scientific
literature for seagrass carbon is mainly based on research from temperate areas, and extending
such knowledge into tropical marine regions is vitally needed. Consequently, a study titled Nature-
based climate change mitigations through management and restoration of seagrass meadows:
quantifying the potential has explored seagrasses for their climate change mitigation potential at
two tropical locations: the seagrass beds of Haad Chao Mai National Park, Trang Province,
Andaman Sea, Thailand and Cairns Harbour, the Great Barrier Reef World Heritage Area
(GBRWHA), Queensland, Australia.
The study was implemented by the IUCN Global Marine and Polar Programme (GMPP) in close
collaboration with the University of Technology in Sydney (UTS) with funding from the TOTAL
foundation. The project supported an international PhD student from UTS, who executed the
research, using both laboratory and field-based experiments and observations. This work provided
insights into the carbon storage of tropical seagrasses.
The project examined carbon in the sediments of pristine and degraded seagrass meadows and
determined how much the loss and degradation of these systems affected their carbon storage
capacity. The project showed that tropical seagrass meadows are equally important as temperate
seagrass meadows for Blue Carbon storage, providing evidence that tropical living seagrasses are
potentially one of the largest pools of organic carbon storage compared to global seagrass areas.
This research also confirmed that the below-ground biomass of seagrasses plays a more important
role as a carbon stock than the above ground parts, storing five times more carbon in the roots
than in the leaves and stems.
This research illustrated the first estimate of changes in the organic carbon stock stored in
sediment after seagrass loss. Estimation of carbon stock showed that the carbon value of
degraded sediment was five times lower than sediment from pristine seagrass beds. These results
confirmed that seagrass loss results in carbon stock loss from the sediment. The study also
produced the first emission factor for seagrass meadows, conveying what amount of stored
carbon would be lost during habitat conversion. These numbers are extremely useful for resource
managers when considering the impact of coastal development application.
This project is the first of its kind in Thailand, and possibly one of only three in Southeast Asia,
including the Philippines and Indonesia. It contributed to the ongoing process of enhancing the
capacity of professionals and in developing appropriate climate change policy, financing, and
management mechanisms in Thailand. It extended current scientific understanding of the role of
seagrasses in climate change mitigation, and provided new Blue Carbon data for a region lacking
significant data. Furthermore, this data informed the global community about carbon stocks in
tropical regions, which is relatively underrepresented in the current global databases.
