Northern peatlands: role in the carbon cycle and probable responses to climatic warming

Boreal and subarctic peatlands comprise a carbon pool of 455 Pg that has accumulated during the postglacial period at an average net rate of 0.096 Pg/yr (1 Pg = 10(15) g). Using Clymo's (1984) model, the current rate is estimated at 0.076 Pg/yr. Long-term drainage of these peatlands is estimated to be causing the oxidation to CO2 of a little more than 0.0085 Pg/yr, with combustion of fuel peat adding almost-equal-to 0.026 Pg/yr. Emissions of CH4 are estimated to release almost-equal-to 0.046 Pg of carbon annually. Uncertainties beset estimates of both stocks and fluxes, particularly with regard to Soviet peatlands. The influence of water table alterations upon fluxes of both CO2 and CH4 is in great need of investigation over a wide range of peatland environments, especially in regions where permafrost melting, thermokarst erosion, and the development of thaw lakes are likely results of climatic warming. The role of fire in the carbon cycle of peatlands also deserves increased attention. Finally, satellite-monitoring of the abundance of open water in the peatlands of the West Siberian Plain and the Hudson/James Bay Lowland is suggested as a likely method of detecting early effects of climatic warming upon boreal and subarctic peatlands.