Kleber and 7 co-authors reported in mid-2022 that permafrost and glaciers in the high Arctic form an impermeable ‘cryospheric cap’ that traps a large reservoir of subsurface methane, preventing it from reaching the atmosphere. Cryospheric vulnerability to climate warming is making releases of this methane possible. On Svalbard, where air temperatures are rising more than two times faster than the average for the Arctic, glaciers are retreating and leaving behind exposed forefields that enable rapid methane escape.
The authors documented how methane-rich springs (from the groundwater) have formed in recently revealed forefields of 78 land-terminating glaciers across central Svalbard, bringing deep-seated methane gas to the surface. Waters collected from these springs during February–May of 2021 and 2022 are supersaturated with methane up to 600,000 times greater than atmospheric equilibration.
Spatial sampling reveals a geological dependency on the extent of methane supersaturation, with isotopic evidence of a thermogenic source. The authors
estimated that annual methane emissions from proglacial groundwaters to be up to 2.31 kt across the Svalbard archipelago. Further investigations into
marine-terminating glaciers indicate future methane emission sources as these glaciers transition into fully land-based systems. The authors' findings revealed that climate-driven glacial retreat facilitates widespread release of methane, a positive feedback loop that is probably prevalent across other regions of the rapidly warming Arctic.
Original working URL: https://www.i2mconsultants.com/downloads/corp/Groundwater_springs_formed_during_glacial_retreat_2022.pdf
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