The carbon budget of upland peat soils

Within the terrestrial biosphere the northern peatlands are the most important carbon store. Gorham (1991) has estimated that 20-30 per cent of the global terrestrial carbon is held in 3 per cent of its land area, i.e. in northern peatlands, storing 450 Gtonnes Carbon (C). Over the Holocene these peatlands have accumulated carbon at an average rate of 0.96 Mtonnes C/yr, making this ecosystem not only a substantial store but also a large potential sink of atmospheric carbon. However, with climate warming, increase drought frequency, and changes in rainfall there is the risk that this important store could be transformed from a net sink to a net source of atmospheric carbon. Climatically driven causes of enhanced carbon loss could be extenuated by other factors, including changes in atmospheric deposition and land management.