Fig. 1: Conceptual model of methane-rich proglacial groundwater springs associated with glacier–permafrost coupling.
From: Groundwater springs formed during glacial retreat are a large source of methane in the high Arctic
a, A continuous cryospheric cap is formed by permafrost extending below land-terminating glacial termini during the later stages of the Little Ice Age on Svalbard (circa 1900). Hydrological connection from the subpermafrost groundwater system to the surface is limited. b, Land-terminating glaciers have retreated due to climate warming, exposing unfrozen ground. Methane-enriched groundwater discharges through proglacial springs. Permafrost develops as glaciers retreat further. However, advective heat associated with groundwater flow and latent heat released during winter icing formation prevent taliks from freezing, allowing continuous groundwater discharge through proglacial springs. Gas hydrate stability zones (GHSZs) are estimated on the basis of modelling by Betlem et al.22. c, Methane-rich subglacial groundwater beneath contemporary marine-terminating glaciers.
