ARCTIC CLIMATE EMERGENCY C

METHANE HYDRATE OFF WEST SVALBARD ISLAND

(North  of Norway)

The West Spitsbergen current, which flows northward through the area north of Norway, has warmed by 1°C over the last 30 years.  The rate of surface warming around Svalbard Is the highest in the Arctic.

Jan 2014 Gas flares have been observed regularly off the coast, probably venting ancioent methane  hydrate.  

Westbrook et al (2009) believe this has caused the top of the gas hydrate stability zone (GHSZ) to move deeper. It used to start around 360 metres beneath the seabed, and now it starts around 400 metres. Hydrate that was once in its upper reaches is now outside the GHSZ and hence has broken down, releasing methane. Report from Svalbard science forum

If this happened across the Arctic, large amounts of methane could be released. Westbrook et al estimate that tens of teragrammes could escape every year- equivalent to 5-10% of the total amount released globally by natural sources.

If this methane reached the atmosphere, it could potentially contribute to climate change, by leading to a vicious circle of more methane leading to higher temperatures, in turn melting more methane hydrates.

The gas plumes rise from the seabed between 150 metres and 400 metres deep, and almost reach the surface before petering out..

"What we know from experience in other places is that the level of activity of these plumes isn't always constant — you can have short periods when the rate of outflow becomes orders of magnitude greater," Westbrook explains. "When that happens the water can't absorb all the methane and some can be released."

At present, measurements of methane concentration in the atmosphere and in the near-surface water in the area of the plumes suggest a small amount of methane is being transferred to the atmosphere.

Professor Westbrook said the area surveyed off the west coast of Svalbard was very different to the area being studied by the research of the East Siberian Arctic shelf  because the water was much deeper and does not have a layer of permafrost sealing the methane under the seabed

Almost none of the Arctic has been surveyed in a way that might detect a gas release like this.

A 2001 paper by the Westbrook team  Timing of methane release from hydrate dissociation on the west Svalbard margin, reports that the Arctic sea floor has been subjected to episodic warming/ cooling cycles that could prime hydrates from depth for rapid release.

In locations where there is significant input of gas beneath the hydrate stability zone, this temperature cycling creates conditions for a ‘rapid’ response to increases in the temperature of the water in the depth range 300-500 m.

This region of the Arctic is projected to warm the very fastest