Active methane plumes over the West Spitsbergen shelf discovered last summer are being driven by warming of an ocean current over the last 30 years, a new study(*) reports. The team on the British research vessel the James Clark Ross from the National Oceanography Centre Southampton (working with scientists from the University of Birmingham, Royal Holloway London and IFM-Geomar in Germany) found more than 250 plumes of bubbles of methane gas rising from the seabed of the West Spitsbergen continental margin at depths of 150 to 400 metres. From the press release:
Graham Westbrook Professor of Geophysics at the University of Birmingham, warns: “If this process becomes widespread along Arctic continental margins, tens of megatonnes of methane per year â€“ equivalent to 5-10% of the total amount released globally by natural sources, could be released into the ocean.”
New Scientist expands the story somewhat, and looks at the total potential methane release in the region:
The methane being released from hydrate in the 600-square-kilometre area studied probably adds up to 27 kilotonnes a year, which suggests that the entire hydrate deposit around Svalbard could be releasing 20 megatonnes a year.
With global methane emissions of the order of 500 – 600 megatonnes per year, that’s a substantial potential addition to the global budget — and there’s a lot more methane hydrate on the East Siberian Shelf that is already showing signs of breaking down.
(*) Westbrook, G.K. et al. Escape of methane gas from the seabed along the West Spitsbergen continental margin. Geophysical Research Letters, 2009; DOI: 10.1029/2009GL039191 (preprint here: well worth a read)