Escape of methane gas from the seabed along the West Spitsbergen continental margin

TLDR

Warming of the West Spitsbergen current by 1 °C over the past three decades has likely reduced the gas hydrate stability zone, increasing methane release from the seabed. The warming reduces the GHSZ, allowing methane hydrates to decompose and release methane into the water column. More than 250 methane plumes were detected at depths of 150–400 m, some rising to within 50 m of the surface, indicating that widespread release could emit tens of teragrams of methane annually.

Abstract

More than 250 plumes of gas bubbles have been discovered emanating from the seabed of the West Spitsbergen continental margin, in a depth range of 150–400 m, at and above the present upper limit of the gas hydrate stability zone (GHSZ). Some of the plumes extend upward to within 50 m of the sea surface. The gas is predominantly methane. Warming of the northward‐flowing West Spitsbergen current by 1°C over the last thirty years is likely to have increased the release of methane from the seabed by reducing the extent of the GHSZ, causing the liberation of methane from decomposing hydrate. If this process becomes widespread along Arctic continental margins, tens of Teragrams of methane per year could be released into the ocean.