Peatlands are a major storage of carbon in the world. They account for 550 Gt caron worldwide. The majority of the carbon stored in peatlands is in the saturated peat soil that has been sequestered over millennia. In the sub (polar) zone, peatlands contain on average 3.5 times more carbon per hectare than the above-ground ecosystems on mineral soil; in the boreal zone they contain 7 times more and in the humid tropics over 10 times more carbon.
Growing source of greenhouse gas (GHG) emissions
The main threat for release of carbon from peatlands arises from the drainage of the large areas of organic wetland (peat) soils for agriculture, forestry and peat extraction all over the world. As a result, the organic carbon that is normally underwater is suddenly exposed to the air, where it decomposes and emits carbon dioxide (CO2). Additionally, increased temperature, from removal of vegetation cover such as forest cover, enhances the rate of CO2 emissions from peat. Also the use of fertilizers, such as used in oil palm plantations, has an accelerating effect on the decomposition rate of peat soils.
Peat fires, such as those take place in Southeast Asia every year and also in Russia, release huge amounts of CO2 as well. Altogether global CO2 emissions amount to at least 2,000 million tonnes annualy, equivalent to 5% of the global fossil fuel emissions.
Another growing source of GHG emissions from peatlands is methane. The scientific database for methane effluxes from peatlands is much larger than that for CO2 or N2O. The following report on Methane emission from peat soils and article on Towards developing IPCC methane 'emission factor' for peatlands (organic soils) give more insights on this matter.
In Indonesia, emissions from peat soils due to logging and drainage contribute 60% to the total Indonesian CO2 emissions (~900Mtons per year). While Indonesia currently has the highest CO2 emissions from peatlands, the degradation of peatlands s a global problem. Download The Global Peatland CO2 Picture for CO2 emissions worldwide inventory.
Impact of climate change on peatlands
Another cause for concern is that climate change poses an enormous challenge to peatlands and CO2 emissions. For instance, warmer summer weather threatens to thaw the large peatland (permafrost) areas of Canada and Russia, causing them to decompose. There is also a risk that fossilised methane, stored under the permafrost areas, could be released.
Marcel Silvius, Programme Head Climate-Smart Land Use