Permafrost and gas hydrate stability: Eurasian ice sheet dynamics and paleo impact Available to Purchase

The paper examines key factors controlling gas hydrate formation on Arctic shelves, including subsea permafrost and ice sheet dynamics, which influence environmental and geotechnical conditions in shallow Arctic seas. It presents results of numerical modelling of the evolution and present-day distribution of relic subsea permafrost and the gas hydrate stability zone (GHSZ) across the Eurasian Arctic shelf over the past 26 000 years. The modelling framework incorporates glacial isostatic adjustment and the impact of the Eurasian Ice Sheet on pressure and temperature conditions affecting hydrate stability. Four main GHSZ types are identified: permafrost-associated; subglacial, formed under high pressures of the ice sheet; post-glacial, preserved due to elevated hydrostatic pressure from sea level rise; and post-permafrost, persisting after permafrost degradation due to the high thermal inertia of marine sediments. The model shows that an extensive subglacial GHSZ developed in the central Barents Sea during the Last Glacial Maximum, with remnants potentially still persisting today. Modelling also reveals recent GHSZ growth near the outer shelf edge, likely linked to sea level rise. These findings highlight geotechnical risks such as seabed weakening, subsidence, slope failure, and methane release critical for Arctic offshore infrastructure and resource development.