High-latitude peatlands cover only about 3% of the world's land surface area, but store approximately 15-30% of global soil carbon reserves. The increasing air temperature can stimulate the decomposition rate of peatland soil carbon, which may increase the release of carbon from soil to atmosphere as carbon dioxide (CO2) and methane (CH4), both important greenhouse gases. In particular, peatlands are the largest natural source of CH4 to atmosphere (CH4 has 23 times more warming potential than CO2). Due to the huge carbon stocks and the more pronounced warming trend in the high-latitude region, it is important to understand and predict the response of high-latitude peatland soils to climate because a substantial change in the release of peatland carbon stocks as CO2 and CH4 could influence the global climate system. A peatland model was developed to simulate the fundamental and important mechanisms and processes that control soil organic carbon dynamics in boreal peatlands. This peatland model was then incorporated into the dynamic organic soil version of the Terrestrial Ecosystem Model (peatland DOS-TEM). Peatland DOS-TEM was first calibrated and then validated with the long-term field experimental data measured from a rich fen peatland in the Alaska Peatland Experiment. After the peatland DOS-TEM was evaluated with experimental data, it was used to simulate the future soil organic carbon dynamics of the rich fen peatland under several CO2 emission scenarios. Our results suggest that the high-latitude peatland might shift from a net sink to a net source of atmospheric carbon at the end of 21st century, resulting in a positive feedback to the warming atmosphere.