| Summary: | The proposed research integrates studies in a range of disciplines (paleoecology, climate, biogeochemistry, geomorphology, geology) to understand the timing, magnitude, and overall contribution of northern cold-climate peatlands and lakes to rapid increases in atmospheric methane (CH4) concentrations (AMC) during the last deglaciation. The study will use comprehensive paleoecological records of northern peatland and lake development to document their past spatial and temporal patterns of CH4 emission. This will enable better prediction of future emissions from northern ecosystems, particularly as surface permafrost thaws under scenarios of climate warming. Methane is a potent greenhouse gas. Its global warming potential is many times that of carbon dioxide. Therefore, in order to develop scenarios of future climate change, it is important to be able to estimate how much methane will be released to the atmosphere due to permafrost degradation. This project will constrain that number. Our results indicated that the interpolar CH4 gradient in the early Holocene was ~65ppb and decreased during the middle Holocene to values ~35ppb that held for the later part of the Holocene. These results are consistent with enhanced early Holocene PanArctic CH4 emissions associated with the final retreat of the Laurentide ice sheet.
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