Methane emissions

Horrific amounts of methane over Laptev Sea

Arctic News,

14 November, 2013

For some time now, very high methane readings have been showing up over the Laptev Sea. Harold Hensel recently posted the image below with the huge areas solidly colored red indicating release of horrific amounts of methane. Harold adds the following comment:

"I am fighting for the lives of my children, grandchildren, and great grandchildren who's lifespan will extend 30 to 40 years from now. I am also fighting for all children of the world, animals, whales, dolphins, flowers and all living things. They are all in peril and we are the ones that may have a chance of doing something about it now. The threat of what is coming must sink in."

As the image below illustrates, high methane emissions, i.e. at 1850 ppb and higher, are more prevalent on the northern hemisphere, while emissions on the southern hemisphere are mostly under 1850 ppb. The contours of North America are visible, with Greenland to the north. Further north, over the Arctic Ocean, the color red dominates, indicating emissions of 1950 ppb and higher.

In which part of the Arctic Ocean are most emissions recorded? The image below shows recent methane readings of 1950 and higher, this time colored in yellow, for a period of just over one day during November 12 and 13, 2013. The largest area colored solid yellow is over the Laptev Sea, just north of Siberia.

Below is an image of the same period as above image, but once more showing methane levels in ranges, i.e. readings of 1950 ppb and higher in red, as well as lower readings in orange and yellow. Over the Arctic Ocean, high methane readings dominate the picture, both readings of 1950 ppb and higher, and readings in the range of 1850 ppb to 1950 ppb.

What makes high methane releases over the Laptev Sea so scary?

Vast amounts of methane are held in sediments under the Arctic Ocean. The Laptev Sea is part of the Eastern Siberian Arctic Shelf (ESAS, the rectangle on the image on the right). Shakhova et al. (2010) estimate the accumulated methane potential for the ESAS alone as follows:

• organic carbon in permafrost of about 500 Gt
• about 1000 Gt in hydrate deposits
• about 700 Gt in free gas beneath the gas hydrate stability zone.

Shakhova et al. in 2008 considered release of up to 50 Gt of predicted amount of hydrate storage as highly possible for abrupt release at any time.

By comparison, the total amount of methane currently in the atmosphere is about 5 Gt.