Tropical peatlands contain three times more carbon in one metre of depth than a fully developed tropical rainforest, and tropical peatlands can be up to 10 metres deep. Around 70% of tropical peatlands are found in Southeast Asia, and their drainage and conversion to other land uses – such as oil palm estates – releases significant quantities of carbon dioxide into the atmosphere. This explains why Indonesia is one of the largest emitters of greenhouse gases after China and the United States, with about half derived from peat fires and decomposition.
Despite their importance, there is still considerable confusion about the way in which carbon is stored and released from peatlands, and the measures which need to be taken to reduce emissions. “Tropical peatlands are known not only for their high carbon emissions in response to land use change, but as hotspots of debate about associated data uncertainties,” says Meine van Noordwijk, chief science adviser at the World Agroforestry Centre and lead author of Mud, muddle and models in the knowledge value-chain to action on tropical peatland conservation.
The knowledge value chain is long and complex. “First, we need to gain a better understanding of peatland processes so that we can measure the emissions accurately,” says Meine. “Then there needs to be a willingness to act – in the past, many governments have been in denial about the scale of peatland emissions – and, of course, an ability to act.” This could involve re-wetting, reforestation and agroforestry, although there is still much debate about which activities are most effective. Just as importantly, says Meine, we need to think about alternative livelihood options for the people who live in peatlands, so that they can continue making a living without threatening the ecology or increasing carbon emissions.
Meine and his colleagues concluded that to shorten the denial and conspiracy-theory stages of debate that have tended to hamper the willingness and ability to act, networks of international and national scientists should be involved at a very early stage in identifying policy-sensitive environmental issues. While drainage of peatlands triggers landscapescale increases in emissions, factors beyond drainage depth, including nutrient supply, may have a major influence on decomposition rates, and therefore emissions. In short, more work needs to be done on both science and policy issues related to peatlands.
Searching for the facts in the Philippines
The peatland is currently under threat of clearance
The Philippines is in the early stages of identifying, measuring and understanding its peatlands. To rectify the gaps in knowledge, Rodel Lasco, country coordinator for the World Agroforestry Centre, and his colleagues estimated the amount of carbon stored in the Caimpugan peatland in Mindanao, one of the most ecologically significant wetlands in the country.
They found that the most important carbon store was peat soil, which stored more carbon than all the above-ground stocks. In total, the Caimpugan peatland, which covers 5487 hectares, stores an estimated 22.9 million tonnes of carbon, and therefore represents a substantial and space-efficient carbon store compared to other forest types in the country.
The peatland is currently under threat of clearance through conversion to agricultural land and by disturbance from ecotourism development. Rodel and his colleagues have advised that activities in and around the area should be monitored closely in order to conserve the peatland’s ecological integrity.
References
Meine van Noordwijk et al. 2013. Reassessing peat-based emissions from tropical land use. ASB Policybrief 36. Nairobi: ASB Partnership for the Tropical Forest Margins Meine van Noordwijk et al. 2014. Mud, muddle and models in the knowledge value-chain to action on tropical peatland conservation. Mitigation and Adaptation Strategies for Global Change,
