Widespread natural methane and oil leakage from sub-marine Arctic reservoirs.

Parceling the anthropogenic and natural (geological) sources of fossil methane in the atmosphere remains problematic due to a lack of distinctive chemical markers for their discrimination. In this light, understanding the distribution and contribution of potential geological methane sources is important. Here we present empirical observations of hitherto undocumented, widespread and extensive methane and oil release from geological reservoirs to the Arctic Ocean.

Exceptions to bed-controlled ice sheet flow and retreat from glaciated continental margins worldwide.

Projections of ice sheet behavior hinge on how ice flow velocity evolves and the extent to which marine-based grounding lines are stable. Ice flow and grounding line retreat are variably governed by the coupling between the ice and underlying terrain. We ask to what degree catchment-scale bed characteristics determine ice flow and retreat, drawing on paleo-ice sheet landform imprints from 99 sites on continental shelves worldwide.

Shallow carbon storage in ancient buried thermokarst in the South Kara Sea.

Geophysical data from the South Kara Sea reveal U-shaped erosional structures buried beneath the 50-250 m deep seafloor of the continental shelf across an area of ~32 000 km. These structures are interpreted as thermokarst, formed in ancient yedoma terrains during Quaternary interglacial periods. Based on comparison to modern yedoma terrains, we suggest that these thermokarst features could have stored approximately 0.