Coastal wetlands are important carbon sinks, all too often ignored as important ecosystems for preserving and indeed fostering and growing, for mitigation of climate change. In January 2013 I looked at how Mangrove forests threatened by Climate Change in the Sundarbans of Bangladesh and India. In December 2013 I featured a guest post on Philippines steps up restoration of mangroves as defence against typhoons, tsunamis, sea level rise. Read more of my posts on blue carbon. Research has shown that Mangroves among the most carbon-rich forests in the tropics (Donato etal 2011).
Now a new study published in Nature Climate Change identifies the importance of preserving the extensive mangrove forests remaining in Indonesia for reducing it's greenhouse gas emissions.
Stopping mangrove deforestation in Indonesia could help slow climate changeProdita Sabarini, The Conversation
Preventing the loss of Indonesian mangroves would help in the global fight against climate change, new research shows.
The study, published recently in Nature Climate Change, estimated that if Indonesia halts mangrove deforestation it could reduce its total greenhouse gas emissions by between 10% to 31%.
That would be globally significant, since Indonesia is among the world’s highest contributors to global emissions – ranked 12th in the world in 2012, according to European Commission figures, behind others led by China, the US and the European Union, and just ahead of Australia.
The study also points to Indonesia’s large-scale shrimp industry, worth US$1.5 billion a year, as being a driver in mangrove deforestation. Many mangroves in Indonesia are being converted into shrimp ponds.
Deforestation is a major national and international challenge. As well as being one of Indonesia’s biggest sources of greenhouse gas emissions, many other studies have found that the loss of forests worldwide is a significant contributor to global greenhouse emissions.
The research team, led by Daniel Murdiyarso from the Centre for International Forestry Research, showed that mangroves in Indonesia stores 3.14 billion metric tons of carbon – or one-third of global coastal carbon stock.
The study explains that mangroves are important because of their high rates of tree and plant growth, coupled with anaerobic, water-logged soils that slow decomposition, resulting in large, long-term carbon storage. Mangroves store three to five times more carbon than rainforests.
But over the past three decades, Indonesia has lost 40% of its mangroves.
In 2005, Indonesia had 2.9 million hectares of mangroves, or almost a quarter of global mangrove ecosystems. That’s down from in 1980, when there were 4.2 million hectares of mangroves.
Indonesia has pledged to cut its greenhouse emissions to 26% by 2020.
According to Professor Murdiyarso, deforestation of Indonesian mangroves contributes to almost half of the global carbon emissions from the destruction of coastal ecosystems, which including marshes, mangroves and sea grasses. Every year, Indonesia loses around 52,000 hectares of mangroves.
The study is significant due to the “the magnitude of the [carbon] stock and the magnitude of emission rate,” Professor Murdiyarso said.
The research team assessed carbon stocks of 38 mangroves plots located in eight sites across the archipelago.
The research team measured the carbon storage in the leaves and roots of mangroves. “Mangroves have a very unique root system above the ground,” Professor Murdiyarso said.
The team also measured carbon storage in the soil by drilling two to three metres underground to collect samples for lab analysis.
The team used deforestation estimates with a stock-change approach to estimate emissions from land use, as well as mitigation potentials.
Tien Wahyuni, a researcher from the Indonesian Ministry of Forestry and Environment’s Dipterocarps Research Centre, said that Indonesian mangroves face various threats.
“Mangroves are being converted for shrimp and fish ponds. But there are other threats as well. In urban areas they are destroyed for land reclamation for residential areas,” she said.
She said the new study on mangroves was important. “Mangroves have a lot of biomass because their roots go deep into the ground.”
The abstract for the study - The potential of Indonesian mangrove forests for global climate change mitigation - reads in full:
Mangroves provide a wide range of ecosystem services, including nutrient cycling, soil formation, wood production, fish spawning grounds, ecotourism and carbon (C) storage1. High rates of tree and plant growth, coupled with anaerobic, water-logged soils that slow decomposition, result in large long-term C storage. Given their global significance as large sinks of C, preventing mangrove loss would be an effective climate change adaptation and mitigation strategy. It has been reported that C stocks in the Indo-Pacific region contain on average 1,023 MgC ha−1 (ref. 2). Here, we estimate that Indonesian mangrove C stocks are 1,083 ± 378 MgC ha−1. Scaled up to the country-level mangrove extent of 2.9 Mha (ref. 3), Indonesia’s mangroves contained on average 3.14 PgC. In three decades Indonesia has lost 40% of its mangroves4, mainly as a result of aquaculture development5. This has resulted in annual emissions of 0.07–0.21 Pg CO2e. Annual mangrove deforestation in Indonesia is only 6% of its total forest loss6; however, if this were halted, total emissions would be reduced by an amount equal to 10–31% of estimated annual emissions from land-use sectors at present. Conservation of carbon-rich mangroves in the Indonesian archipelago should be a high-priority component of strategies to mitigate climate change.
Carbon intensity of Mangrove land use change
You can read an in-depth article at Centre for International Forestry Research (CIFOR) Forestry News blog: Indonesia’s best hope for slowing climate change.
Watch a youtube video of Boone Kauffman from the Center for International Forestry Research (CIFOR) on Climate change implications of land cover change in mangrove ecosystems. Kauffman was one of the co-authors of the above study. After watching this you might not want to eat another prawn cocktail made with shrimp cultivated through aquaculture in Asia in former mangrove forest areas.
- Daniel Murdiyarso, Joko Purbopuspito, J. Boone Kauffman, Matthew W. Warren, Sigit D. Sasmito, Daniel C. Donato, Solichin Manuri, Haruni Krisnawati, Sartji Taberima and Sofyan Kurnianto, The potential of Indonesian mangrove forests for global climate change mitigation, Nature Climate Change (2015) doi:10.1038/nclimate2734 (abstract)
- Lead photo: Mangrove at Pulau Dua Natural Reserve (2015) by Aulia Erlangga/ CIFOR on Flickr (CC BY-NC-ND 2.0)
CIFOR scientists and partners from the Indonesian Ministry of Marine and Fisheries install a sedimentation and carbon stock measurement tool called the Rod Surface Elevation Table Marker Horizon (RSET-MH) in various sites along the Pulau Dua coastline.
- 2nd photo: Measuring mangroves (2013) by Kate Evans for Center for International Forestry Research (CIFOR)/Flickr (CC BY-NC-ND 2.0)
Center for International Forestry Research (CIFOR) scientist and researcher measure the diameter of mangrove trees in a study on above-ground and below-ground biomass in mangrove ecosystems, part of Sustainable Wetlands Adaptation and Mitigation Program (SWAMP). Kubu Raya, West Kalimantan, Indonesia.