Modelling Holocene carbon accumulation and methane emissions of boreal wetlands – an Earth system model approach
[摘要] Since the Last Glacial Maximum, boreal wetlands have accumulated substantialamounts of peat, estimated at 180–621 Pg of carbon. Wetlands havesignificantly affected the atmospheric greenhouse gas composition in thepast and will play a significant role in future changes of atmosphericCO2 and CH4 concentrations. In order to investigate those changeswith an Earth system model, biogeochemical processes in boreal wetlands needto be accounted for. Thus, a model of peat accumulation and decay wasdeveloped and included in the land surface model JSBACH of the Max PlanckInstitute Earth System Model (MPI-ESM). Here we present the evaluation ofmodel results from 6000 yr BP to the pre-industrial period. Over thisperiod of time, 240 Pg of peat carbon accumulated in the model in the areasnorth of 40° N. Simulated peat accumulation rates agree well withthose reported for boreal wetlands. The model simulates CH4 emissionsof 49.3 Tg CH4 yr−1 for 6000 yr BP and 51.5 Tg CH4 yr−1 for pre-industrial times. This is within the range of estimates inthe literature, which range from 32 to 112 Tg CH4 yr−1 for borealwetlands. The modelled methane emission for the West Siberian Lowlands and HudsonBay Lowlands agree well with observations. The rising trend of methaneemissions over the last 6000 yr is in agreement with measurements ofAntarctic and Greenland ice cores.
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[效力级别] [学科分类] 地球化学与岩石
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