The impact of permafrost degradation on methane fluxes : a field study in Abisko

Abstract: All over the arctic and sub-arctic region global warming is affecting permafrost. When permafrost thaws, organic material becomes available for decomposition, hence an increase of greenhouse gas emissions to the atmosphere. In the northernmost of Sweden, on a mire close to Abisko, a snow manipulation project is ongoing. The experiment is trying to mimic predictions of future conditions and advance the thawing of permafrost. This is done by setting up snow fences which concentrated the snow to a certain area. In this thesis the measurements of methane were conducted inside of the existing snow manipulation project with the closed chamber technique, both in control and manipulated plots. Other variables that could affect the emissions were also collected or measured. The results show much higher methane emissions from manipulated plots. Average emissions from manipulated plots were 0.66 mg CH4 m-2 h-1 compared to 0.16 mg CH4 m-2 h-1 from control plots. Variables that showed the highest correlation with the methane flux was water table and active layer. Higher water table and thicker active layer for manipulated plots (higher emissions of CH4) and the opposite for control plots (lower emissions of CH4). If the trend of the global warming is continuing it will lead to even more thawing of permafrost. Then even more organic material will be available for decomposition and even more methane will be produced, adding to the global warming.