In most tropical peatlands, peat accumulation commenced 3,500-6,000 cal yrs BP but, in some areas, investigations have revealed much older dates for the onset of peat deposition, ranging from Late Pleistocene through to the early Holocene.
The current estimate of the total area of undeveloped tropical peatland is in the range 30 – 45 million hectares, which is approximately 10-12% of the global peatland resource; tropical peatlands may store >30% of the total global peatland carbon.
Many tropical peatlands are actively accumulating peat (i.e. burial of C) or are in a steady state, although evidence suggests that climatic and, in particular, land use changes have resulted in conditions under which peat deposits act as atmospheric carbon sources (i.e. higher degradation than burial of organic matter) at many sites.
Role of Tropical Peatlands
Tropical peatlands play important roles regionally and locally in the water cycle and climate and landscape stabilisation; in natural peat swamp forest the surface layer of peat, in which the water table fluctuates over time (acrotelm), may be flooded for nine months of the year.
Tropical peat swamp forest resources and natural functions are being damaged severely by land development, legal and illegal logging and fire; they may soon be destroyed forever with potentially devastating environmental consequences regionally and globally.
Important Carbon sinks
Much of the recent interest in tropical peatlands results from their importance as carbon sinks and stores and their role in carbon cycling between the earth’s surface and the atmosphere.
In tropical peatlands, both the vegetation and underlying peat constitute a large and highly concentrated carbon pool, which, upon degradation releases greenhouse gases with a significant effect on global environmental change processes.
The total current CO2 emissions from tropical peatlands of approximately 2000 Mt yr-1 equals almost 8% of global emissions from fossil fuel burning.
Human induced peat swamp forest ecosystem degradation causes the natural resource functions of tropical peatlands to fail, converting them permanently from net carbon sinks to net carbon sources.
Status of Tropical Peatlands
Current land use and land practise developments give little cause for optimism. While deforestation rates on non-peatlands in SE Asia have decreased somewhat owing to depletion of forest resources, those on peatlands have been stable (on average) for the last 20 years.
In 2005, 25% of all deforestation in SE Asia was on peatlands. Apart from logging for wood production, peatland deforestation has increased in order to convert the land to oil palm and timber plantations, which require intensive drainage and cause the highest CO2 emissions of all land uses.
Yogyakarta Statment on Carbon-Climate-Human Interactions on Tropical Peatlands, Indonesia, 27-31 August 2007 Yogyakarta Statement.pdf (PDF)
For more information please look at www.carbopeat.org