Scientists and Arctic observers have been stunned by the lack of sea ice in the Siberian seas this October. A combination of offshore winds last winter, record summer heat, an in influx of warm, salty water from the far north Atlantic has raised the ocean heat content of the waters of the Siberian seas and the Eurasian side of the Arctic to unprecedented high levels. That warm water has been mixing this October as winds and the long Arctic night cool the surface. But that mixing is bringing up never-before-seen amounts of the greenhouse gas methane which is about 70 to 80 times as potent at warming the climate as CO2.
Scientists on the Russian research ship Akademik Keldysh talked with the Guardian newspaper to report their shocking discovery. www.theguardian.com/…
“At this moment, there is unlikely to be any major impact on global warming, but the point is that this process has now been triggered. This East Siberian slope methane hydrate system has been perturbed and the process will be ongoing,” said the Swedish scientist Örjan Gustafsson, of Stockholm University, in a satellite call from the vessel.
In other words, a tipping point has been crossed. As “Atlantification” of the waters on the vast Siberian continental shelf, the largest shelf on earth, progresses the release of methane will increase. The ingress of Atlantic waters to the Arctic began decades ago and has intensified this summer. Because record ocean heat has been measured in the north Atlantic this year, Atlantification of the Arctic will likely increase over the next two years.
The 60-member team on the Akademik Keldysh believe they are the first to observationally confirm the methane release is already under way across a wide area of the slope about 600km offshore.
At six monitoring points over a slope area 150km in length and 10km wide, they saw clouds of bubbles released from sediment. At one location on the Laptev Sea slope at a depth of about 300 metres they found methane concentrations of up to 1,600 nanomoles per litre, which is 400 times higher than would be expected if the sea and the atmosphere were in equilibrium.
Igor Semiletov, of the Russian Academy of Sciences, who is the chief scientist onboard, said the discharges were “significantly larger” than anything found before. “The discovery of actively releasing shelf slope hydrates is very important and unknown until now,” he said. “This is a new page. Potentially they can have serious climate consequences, but we need more study before we can confirm that.”
Sea ice forum contributor “A Team” explains the figure below.
The animation below provides a flash comparator of the 0 and 30m temperatures with the same color definitions of temperature. The 30m is considerably warmer in the Bering Strait and Chukchi region. That holds for the Laptev as well possibly reflecting AW intrusion.
The high salinity of the water is the give away that it is Atlantic water intrusion. Siberian shelf water is a mixture of fresh Siberian river water and sea water. Because it is mostly river water Siberian shelf water is very fresh for seawater. The warm water flowing along the Siberian shelf margin is salty and almost certainly of Atlantic origin.
Here’s the Mercator Ocean map showing the high salinity Atlantic water intruding into the Barents, Kara and Laptev seas at a depth of about 100 feet. Note the fresh Siberian shelf water in blue in the east Siberian sea. That water originated mainly from Siberian rivers.