A model was constructed that projects the presence or absence of Sphagnum-dominated peatlands in climatic space using two variables: mean annual temperature (MAT) and mean annual total precipitation (MATP). The climatic variables in the model were then coupled to those measured at weather stations in order to plot the projected distribution of Sphagnum-dominated peatlands in North America. The projected distribution was then compared to the current bog and poor fen distribution that was reconstructed from the abundance of Sphagnum spores in cores obtained from lake sediments. That comparison revealed that the Sphagnum-dominated Peatland Distribution Model (SPDM) had an accuracy of 90%. The the climatic variables in the SPDM were then coupled with the reconstruction of the current climate (0ka BP) produced by two General Circulation Models (GCMs). The resulting geographic projections were then compared to the current distribution of Sphagnum-dominated peatlands. Results indicated that the accuracy of the Canadian Climate Centers (CCC) GCM output varied between 77 and 82% while the General Fluid Dynamics Laboratory (GFDL) GCM had an accuracy of 56%. Errors for both GCMs were mostly located in areas immediately east of the Rocky Mountains and in north-eastern North America. The SPDM was then coupled with the GCM reconstructions for the climate at 6ka BP and the resulting geographic distribution was compared to the distribution of Sphagnum-dominated peatlands that was reconstructed from Sphagnum spore counts in lake sediments for the same time period. Results indicated that the CCC output had an accuracy of 70% while the GFDL output was 45% accurate. Errors produced by the changes in climate between 6ka BP and 0ka BP (anomalies) projected by both GCMs were also evaluated. The accuracy for the CCC GCM anomalies was 69% while the GFDL anomalies accuracy was equal to 40%.

Key words: bogs, climate reconstruction, General Circulation Models, poor fens, Spahgnumspores, Sphagnum abundance