Saturday, 8 July 2017

Methane clathrates - Cheers, the champagne bottle is open

Methane News from Shakhova and Semiletov



ESAS , Semiletov, 2012

Nick Breeze has conducted an extraordinary interview with Dr. Natalia Shakhova and Dr. Igor Semiletov.

After Dr. Natalia Shakhova and Dr. Igor Semiletov have stirred up the public with the prediction of a 50 Gigaton methane burst, it has been silent from this side for a while. Now they are back with very clear and unvarnished statements.

Methane in the Arctic Shelf


There is a big reservoir of Methane stored in the East Siberian Arctic Shelf (ESAS).
Shakhova and Semiletov currently estimate that of the 2,000,000 sq km’s that comprise the ESAS, 200,000 sq km’s (10%) are what they would call hotspots, areas where methane emissions are observed as being far greater than in the lower background area.“
Shakhova: „It’s about… try the difference between about 3 milligrams per square metre per day [for background areas] or 3,000 grammes per square metre per day.“
Dr. Semiletov added that the 5 billion tonnes of methane that is currently in the Earth’s atmosphere represents about one percent of the frozen methane hydrate store in the East Siberian Arctic Shelf.“

Cheers, the champagne bottle is open


The methane bottle is uncorked. There is a layer of permafrost in the subsea sediments, that hinders methane to be released since up to one million years. It‘s over now.
Shakhova: „We use an analogy where we compare the East Siberian Arctic Shelf to a bottle of champagne. So the gas produces within this bottle and it keeps accumulating as long as the cork serves as an impermeable lid. This lid is subsea permafrost. Before it was just permafrost [on land] but after it was submerged it became subsea permafrost and served to preserve an increasing amount of gas produced from its release to the ocean and atmosphere above. While this lid is impermeable, there is nothing to worry about. But when this lid loses its integrity, this is when we start worrying.“

No way to stop


Once the bottle of methane deposits of the subsea sediments is uncorked, there is no way to stop this process, that began „thousands of years ago“.
Shakova: „Emissions that are occurring right now are the result of a combined effect of natural and  anthropogenic warming and they will be accelerated until warming is turned to cooling. Even after it happens, there is no mechanism to stop permafrost disintegration in the ESAS besides shelf exposure above the sea level that would serve to freeze the gas migration paths so that they integrate with the permafrost.“
Because the shelf area is very shallow (mean depth is less than 50 metres), a fraction of these emissions will reach the atmosphere. The problem is that this fraction would be enough to alter the climate on our planet drastically.“

Summary


There are huge amounts of methane stored under layers of permafrost in the sediments of the East Siberian Arctic Shelf. The permafrost is going to disintegrate, the bottle is uncorked. There is no mechanism to stop this process.
AND there are other sources of huge methane release, e.g. melting permafrost ashore.

AND there are lots of other self-reinforcing feedback loops, that lead to an exponential warming of our planet.

Where do we go from here?


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