Saturday, 31 October 2015

More on possible methane vent hole in the Arctic ice

Methane Vent Hole In Arctic Sea Ice?

30 October, 2015

Methane vent hole in the ice?

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.

[ click on image to enlarge ]

Could this have been an iceberg? If so, ice concentration should have been higher, rather than lower. More likely is that this is a vent hole with methane rising through cracks in the sea ice.

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".


Naval Research Laboratory 30-day animation are added below for temperature, concentration, salinity and thickness of the sea ice. Click on each of them to view full versions.




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 theGakkel Ridge. The fault continues as the Laptev Sea Rift, on to a transitional deformation zone in theChersky Range in Siberia, then the Ulakhan Fault between the North American Plate and theOkhotsk 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

In September 2005, extremely high concentrations of methane (over 8000 ppb, see image on the right) were measured in the atmospheric layer above the sea surface of the East Siberian Shelf, along with anomalously high concentrations of dissolved methane in the water column (up to 560 nM, or 12000% of super saturation).

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. Methane levels are as high as 2345 ppb. 

Note that the above two images have different scales. The data comes from different satellites. 

Climate Plan

The situation is dire and calls for comprehensive and effective action, as discussed at the Climate Plan.

1 comment:

  1. Excellent and diligent work Sam, but in answer to your final sentence, can anything really be done...? We know that what the data/science tells us is dire, we know that the academics understand this, we assume the politicians are up to speed even, but what for the results? In reality we know that this requires considerable effort on the part of all humans, it is a bitter pill to swallow for the masses... COP21 was all well and good, but just take for example the UK government, they are continuing their policy of fracking and hydrocarbon exploration, yet impeding the renewables sector. I think we've missed the bus here. It is too little, too late...