Methane (CH4) is a greenhouse gas contributing to the global climate change. Global CH4 fluxes are increasing, and positive trends have been reported in boreal and Arctic regions. These atmospheric CH4 “bursts” in northern habitats are likely related to the activation of old hydrocarbon stocks and CH4 hydrates. These stocks were trapped within and beneath permafrost soils and glaciers over the past millennia but are now being mobilized through the climate change. Permafrost soils and glaciers are often rapidly eroding along their coastal boundaries where sudden emissions of CH4 have been previously observed but where data on fluxes are scarce. In this project we hypothesize that effluxes during coastal erosion of glaciers and permafrost represents an important natural CH4 source in the changing Arctic. We further hypothesize that large but short-lived emissions are triggered by extreme meteorological events as well as subglacial and sub-permafrost flushing.
Addressing the need for continuous CH4 flux assessment in these biogeochemically active parts of the cryosphere, we aim to test our hypotheses using a system combining real-time visualization of CH4 emissions by a hyperspectral camera and ecosystem-scale estimations by eddy covariance coupled to a laser-based CH4 sensor. These analyses will be complemented with concentration and ?13C-CH4 measurements allowing process understanding of the CH4 cycle. Selected gas samples will be dated using ?14C-CH4 analysis to evaluate whether recent or old carbon is sourcing observable emissions. Our comprehensive approach will also include continuous estimates and modelling of glacial and permafrost discharge as well as hydro-acoustic surveys over large area of the coast to quantify bubble fluxes. Considering that permafrost and glacial ecosystems are undergoing rapid transition and can be expected to be influenced even more strongly in the future, it is important to understand how these effects reflect on their CH4 budget.