In October 2015, an area appeared in the Arctic sea ice where the temperature of the ice was a few degrees Celsius higher and where ice concentration and salinity levels were substantially lower than the surrounding ice. The image below pictures the situation on October 11, 2015.
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Malcolm Light comments: "The whole of the Arctic seabed is covered with methane hydrates and NASA satellites should have long ago defined where the major plumes were coming out. It is clearly a surface methane vent hole in the ocean ice analogous to the large methane vent holes that appeared all over northern Siberia this year. It means we have overheated the Arctic seafloor to the extent where the methane hydrates are now unstable and we could have further major releases at any time. We have already lit the fuse on a giant methane subsea permafrost bomb in the Arctic which can go off at any moment."
Roger Caldwell responds: "I think it's upwelling warm water. There is a ridge right below the spot. I can see warm spots through the ice on the nullschool program. The warm water comes through the Bering Strait and sinks to the mid levels. When it gets to the ridge it flows upward, making a temporary polynya."
The image below shows warm water entering the Arctic Ocean from the Pacific Ocean (through the Bering Strait) and the Atlantic Ocean, with the dark-red color of many areas in the Arctic Ocean indicating warm waters, including an area close to the North Pole marked by the red circle. So, the spot could indeed be a polynya caused by upwelling of warm water. Alternatively to the Pacific Ocean, the warm water could have originated from the Atlantic Ocean. In the Fram Strait, near Svalbard, sea surface temperatures as high as 11.9°C or 53.5°F were recorded on October 28, 2015, i.e. 9.6°C or 17.2°F warmer than 1981-2011 (at the location marked by the green circle).
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The image below shows that sea surface temperatures as high as 12°C or 53.5°F were recorded near Svalbard on October 31, 2015, i.e. 9.7°C or 17.4°F warmer than 1981-2011 (at the location marked by the green circle).
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| A zone of increased heat near the North Pole which may be related to large quantities of gas released from a group of extremely pyroclastic carbon dioxide-rich volcanoes located at the Gakkel Ridge |
Malcolm Light adds:
"Sohn et al. (2007) outlined how the sequence of extreme pyroclastic eruptions occur along the Gakkel Ridge (85°E volcanoes) at an ultra-slow plate spreading rate (<15-20 mm/year). These volcanoes formed from the explosive eruption of gas-rich magmatic foams. Long intervals between eruptions with slow spreading caused huge gas (volatile) build up high storage pressures, deep in the crust.
Extension of the 85°E seismic swarm occurred over 3 months but later earthquakes were caused by large implosions from the explosive discharge of pressurized magmatic foam from a deep-lying magma chamber through the fractured chamber roof which rapidly accelerated vertically, expanded and decompressed. There were many periods of widespread explosive gas discharge from 1999 over two years detected by small-magnitude sound signals from seismic networks on the ice.
Pyroclastic rocks contain bubble wall fragments and were widely distributed over an area of more than 10 square km. Deep fragmentation was caused by the accumulation of a gas (volatile) foam within the magma chamber which then fractured, formed a pyroclastic fountain 1-2 km high in the Arctic Ocean and spread the pyroclastic material over a region whose size was proportional to the depth of the magma chamber (see above table). A volatile carbon dioxide content of 14% (Wt./Wt. - volume fraction 75%) is necessary at 4 km depth in the Arctic Ocean to fragment the erupting magma."
As said, with water this warm reaching the center of the Arctic Ocean from the Atlantic and Pacific Oceans, the threat is that added heat from volcanic activity or pressure shocks from underwater earthquakes or landslides will trigger (further) destabilization of methane hydrates at the seafloor of the Arctic Ocean.
Below follows some more background.
Animations
Naval Research Laboratory 30-day animations are added below for temperature, concentration, salinity and thickness of the sea ice. Click on each of them to view full versions.
Temperature | Concentration | |
Salinity  | Thickness  |
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Background on tectonic plates and faults
A major fault line crosses the Arctic Ocean, forming the boundary between two tectonic plates, the North American Plate and the Eurasian Plate. These plates slowly diverge, creating seismic tension along the fault line. From where the Mid-Atlantic ridge enters the Arctic Ocean, it is called the Gakkel Ridge. The fault continues as the Laptev Sea Rift, on to a transitional deformation zone in the Chersky Range in Siberia, then the Ulakhan Fault between the North American Plate and the Okhotsk Plate, and then continues as the Aleutian Trench to the end of the Queen Charlotte Fault system.
The situation in October 2013
High methane readings were recorded for a period of just over one day, October 19 - 20, 2013, as shown in the images below. Indicated in yellow are all methane readings of 1950 ppb and over.
To pointpoint more closely where methane is venting along the Laptev Sea Rift, the image below gives readings for October 20, 2013, pm, at just three altitudes (607 - 650 mb).
Satellite measurements recorded methane readings of up to 2411 ppb on October 20, 2013.
Methane venting in the Laptev Sea in 2005 and 2007
For further reference, large amounts of methane have been venting in the Laptev Sea area in previous years. Added below is an edited part of a previous post, Unfolding Climate Catastrophe.
The authors conclude: "Since the area of geological disjunctives (fault zones, tectonically and seismically active areas) within the Siberian Arctic shelf composes not less than 1-2% of the total area and area of open taliks (area of melt through permafrost), acting as a pathway for methane escape within the Siberian Arctic shelf reaches up to 5-10% of the total area, we consider release of up to 50 Gt of predicted amount of hydrate storage as highly possible for abrupt release at any time".
In 2007, concentrations of dissolved methane in the water column reached a level of over 5141 nM at a location in the Laptev Sea. For more background, see the previous post, Unfolding Climate Catastrophe.
Methane levels in October 2015
The image below shows high methane concentrations over the Arctic Ocean on October 11, 2015, pm, at 840 mb, i.e. relatively close to sea level.
The image below shows high levels of methane over the Arctic Ocean at higher altitude (469 mb) on October 28, 2015, pm, when methane levels were as high as 2345 ppb.
Note that the above two images have different scales. The data are from different satellites. The video below shows images from the MetOp-2 satellite, October 31, 2015, p.m., at altitudes from 3,483 to 34,759 ft or about 1 to 11 km (241 - 892 mb).
Peak methane levels were as high as 2450 ppb on November 1, 2015.
Update: Warm Water in Arctic Ocean
On November 5, 2015, sea surface temperatures as high as 8.5°C or 47.3°F showed up in the Bering Strait, an anomaly of 6.6°C or 11.9°F, while sea surface temperatures as high as 14.4°C or 57.9°F showed up near Svalbard on November 5, 2015, a 12.2°C or 22°F anomaly. The situation is illustrated by the image below.
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Climate Plan
The situation is dire and calls for comprehensive and effective action, as discussed at the Climate Plan.
Links
- Explosive volcanism on the ultraslow-spreading Gakkel ridge, Arctic Ocean, Sohn et al. (2007, published 2008)
http://www.nature.com/nature/journal/v453/n7199/full/nature07075.html
- Unfolding Methane Catastrophe
http://arctic-news.blogspot.com/2013/10/unfolding-methane-catastrophe.html
- Further Confirmation of a Probable Arctic Sea Ice Loss by Late 2015, by Malcolm P.R. Light (Sep. 1, 2012)
http://arctic-news.blogspot.com/2012/09/further-confirmation-of-a-probable-arctic-sea-ice-loss-by-late-2015-loss.html
In October 2015, an area appeared in the Arctic sea ice where the temperature of the ice was a few degrees Celsius...
Posted by Sam Carana on Friday, October 30, 2015
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