Role of Mangroves in Climate Change Mitigation and Adaptation
The capacity of mangroves, sea grasses, and salt marshes to sequester carbon dioxide from the atmosphere is becoming increasingly recognized at an international level. Of all the biological carbon, also termed as ’green carbon’, captured in the world, over half (55%) is captured by mangroves, sea grasses, salt marshes, and other marine living organisms, which are also known more specifically as ’blue carbon’.
Mangroves, salt marshes, and sea grasses form much of the earth’s blue carbon sinks. These coastal vegetations sequester carbon far more effectively (up to 100 times faster) and more permanently than terrestrial forests. Further, studies have shown that per hectare, mangrove forests store up to five times more carbon than most other tropical forests around the world. This ability of mangroves and other coastal vegetation to store such large amounts of carbon is, in part, due to the deep, organic rich soils in which they thrive. The entangled root systems of mangroves, which anchor the plants into underwater sediment, slow down incoming tidal waters, allowing organic and inorganic material to settle into the sediment surface. The sediments beneath these habitats are characterized by typically low oxygen conditions, slowing down the decay process and rates, resulting in much greater amounts of carbon accumulating in the soil. In fact, mangroves have more carbon in their soil alone than most tropical forests have in all their biomass and soil combined.
Carbon offsets based on the protection and restoration of coastal vegetation could therefore be far more cost effective than current approaches focused on terrestrial and peat forests, even before taking into consideration the enormous additional benefits to fisheries, coastal protection, and the livelihoods of coastal inhabitants.Therefore, cutting down mangroves means releasing larger amounts of carbon into the atmosphere. This in turn causes the wet soil to dry up, leading to the release of even more stored carbon into the atmosphere. Estimates suggest a range of between 150 million to 1 billion tonnes of CO2 that is emitted annually due to the destruction of mangrove forests globally. Thus, at the global scale, coastal wetland destruction could account for 1-3% of industrial emissions; a number that is on the rise as more and more coastal wetlands are destroyed every year around the world.
Thus, mangrove forests offer a unique and highly efficient approach to climate change mitigation and adaptation.
Challenges Facing Mangrove Ecosystems
However, despite such diversity in the roles of mangroves, these ecosystems are still often seen as valueless wastelands available for other uses. Such negligence toward protecting mangroves is leading to a faster rate of destruction for mangroves all over the world than for tropical forests. The most substantial loss of the world’s mangrove cover is due to their conversion to other land uses, such as urban area expansion, industrial development, aquaculture, agricultural development, and charcoal making. Among these, shrimp aquaculture has been the single biggest driver of mangrove destruction, particularly in Southeast Asia. Since the 1970s, aquaculture development has decimated vast areas of mangrove forests in the Gulf of Thailand, Vietnam, Java and Kalimantan in Indonesia, and the Philippines. Every year thousands of tons of shrimps from aquaculture farms from Southeast Asia are exported to western markets.
One of the key challenges facing mangrove conservation is inadequate understanding of their multiple roles due to poor research, particularly in the areas of climate change mitigation and adaptation. As compared to terrestrial ecosystems, the research focus on coastal and marine systems is about a decade behind. There are isolated examples of a few very useful research studies, but a comprehensive account of the various ecological, economic, and bio-physical roles played by mangrove forests is still lacking. In order to raise awareness of the multiple benefits of mangrove ecosystems, there is a need to conduct more research and also focus more on expanding mangrove areas in participation with local communities and other key stakeholders.
RECOFTC has been following a similar approach in eastern Thailand in Pred Nai village, Trat Province, with very encouraging results for the past two decades. Based on a successful engagement with local communities to restore a large area of degraded mangroves, the project is now expanding its engagement with neighboring villages through a learning network established at the grassroots level. A community based learning center established in Pred Nai village links natural resource and environmental conservation initiatives at the local level and establishes communication between concerned units at the provincial level and community members who play a vital role in natural resource conservation in Trat. These efforts are also aimed at promoting policy support for local authority decentralization, and providing technical and technological support to local officers on natural resources management planning, and strategies on strengthening community self-management. This is an important initiative to better understand the roles of mangroves in local livelihoods and also for climate change mitigation and adaptation at the local level.
Mangroves for the Future (MFF) program, IUCN
FAO’s work on mangrove conservation and management
– See more at: http://www.recoftc.org/site/resources/Mangroves-more-Carbon-Rich-and-Important-for-Climate-Change.php#sthash.oBIgD5cA.dpuf