GLOBAL WARMING POTENTIAL OF DRAINED AND UNDRAINED PEATLANDS IN ESTONIA: A SYNTHESIS

We estimated the global warming potential of Estonian peatlands (transitional fens and ombrotrophic bogs) based on greenhouse gases (GHG) CO2, CH4, and N2O and carbon (C) accrual in biomass, and the effects of drainage on these processes. Data were derived from a review of the literature of boreal peatlands. Areal estimates of peatland types were Multiplied with the values of the interquartile range of literature-derived GHG fluxes. The effect of drainage and radiative forcing of Estonian peatlands were also evaluated. Annual emission Of CO2, CH4, and N2O is estimated to be 278 to 1,056 x 10(3) Of CO2 equivalent (eq), of which CO2 makes up 22 to 44%, CH4 53 to 73%, and N2O 3 to 5%. The annual efflux is 419 to 676 x 10(3) CO2 eq year(-1) from drained peatlands, and - 141 to 380 x 10(3) CO2 eq year(-1) from the undrained peatlands. The annual loss of C from peatlands is estimated to be 38 to 86 tons C x 10(3) year(-1). Thus due to drainage, Estonia's transitional fens and ombrotrophic bogs have gone from being sinks to sources of C.