Friday, May 10, 2013

Antarctic methane peaks at 2249 ppb

Methane levels in the atmosphere above Antarctica peaked at 2249 parts per billion on May 9, 2013.

The chart below shows that very high levels of methane have been recorded over Antarctica for some time now.These very high methane emissions occur on the heights of East Antarctica. The map below shows the highest altitudes on Antarctica colored red.

Antarctic map by the U.K.-based Centre for Polar Observation & Modelling (CPOM)

Antarctica is covered in a thick layer of ice, as indicated by the image below. It appears that these very high emissions are caused by methane from hydrates that is escaping in the form of free gas bubbling up through the ice sheet.

Antarctic map showing the height of the ice sheet created with CryoSat-2 data
The danger is that such emissions will escalate, not only over Antarctica, but also on the Qinghai-Tibet Plateau and in the Arctic.

Peter Carter, contributor to the Arctic-news blog, comments:
“This is of enormous planetary emergency significance because unlike the Arctic methane hydrate is the only possible source of this extraordinary emission of Antarctic methane.”

Albert Kallio, also contributor to the Arctic-news blog, comments:
“The Antarctic methane rise is an extremely worrying phenomenon. It can be caused by two processes. Neither a direct sunlight, nor atmospheric warming, can reach to the base of the ice sheet. However, it is still almost certainly to be a result of global warming – teleconnections – like other recent methane rises seen over the Arctic Ocean, Siberia and North American tundra:

(1) Theoretically, it could be a result of melt water percolation through Antarctic ice sheet to its base, and then, thawing the permafrost soil beneath the ice sheet.

(2) I suggest that methane is coming out from the Antarctic soils because of isostatic equilibrium change that has occurred between the weight loads levied by the East Antarctic Ice Sheet (EAIS) and that of the West Antarctic Ice Sheet (WAIS).

While the East Antarctic ice accumulates weight, the West Antarctic ice loses its weight due to ablation (melting). As the fluids both in the asthenosphere and the crust are incompressible, the changing fluid pressure of one channels from one to the other via the subterranean fluid conduits. These can consist both hot magma and water which transports heat from deep towards the surface.

Asthenosphere is made of extremely water-soluble, but dense rock, Peridotite. If incursion of water from above gets into the peridotite, it hydrates and starts to melt. Hydrogen in water molecule tears molecules like NaCl apart to Na+ and Cl- as the bouncing water molecule swipes its two hydrogen tails in collisions with the other molecules. While NaCl is completely knocked down by water molecule’s hydrogen, in case of Peridotite molecules only some atomic parts are blown out, hence the process is called “partial melting”.

The First Nations UN General Assembly motion’s geophysical annotations attribute the onset of the Ice Ages completely for the continental plates drifting phenomenon. The continental plate drifting had caused crustal shearing at very high latitudes. The newly formed faults and the shearing of the continental plate then allowed water to reach Peridotite to liquefy it. This caused large lava floods onto sea floor boiling the ocean's water which then landed as snow.

My view is that Antarctica has developed now an adequate disequilibrium which pumps water into Peridotite, which then liquefies in the asthenosphere (and also in the crustal plate where there are Peridotite pockets within the Antarctic plate).

As a result of the ice sheet disequilibrium, some ice and water has forced their way into the Peridotite reservoirs, now liquefying it. This liquefaction allows heat to escape in the forms of heated water (a creation of subglacial geysers), or rock incursions such as lava floods and subglacial volcanoes that have started to develop beneath the Antarctic Ice Sheet. The Gamburtsev Range is probably this kind of series of volcanoes and is a candidate for the EAIS methane.

As the heat starts rising more to the surface to (the base of the East Antarctic Ice Sheet), the ground warms and releases methane which is then dissolved into subglacial Antarctic water currents. (There are plenty of subglacial water currents and lakes to transport methane and dissolve it in water beneath Antarctic ice.)

The accumulation of water, pre-existing faults in bed rocks under the Antarctic ice sheet and local weight loads all determining where and when the methane starts oozing out once the ice sheet has now sufficiently changed from its multi-millennial equilibrium.”
The graph below shows when glaciation and build-up of the ice sheet took place on Antarctica back in history.



Above graph also shows the Paleocene-Eocene Thermal Maximum (PETM). Wikipedia adds that due to the coarse sampling and averaging involved in this record, it is likely that the full magnitude of the PETM is underestimated by a factor of 2-4 times its apparent height. Temperature anomaly differences between geographic areas are also indicated on the map below, from the University of Texas Arlington Climate Research Group.

Geographical reconstruction for the PETM from the PALEOMAP Project (www.scotese.com) .
Boxes indicate reconstructed surface temperature anomalies for the PETM relative to Paleocene background
temperatures based on oxygen isotopes, Mg/Ca ratios and TEX86 (compiled by Appy Sluijs)
When comparing today's situation with the situation millions of years ago, it's good to keep the following points in mind:
  1. Methane hydrates on Antarctica formed after glaciation, making it likely that the quantity of methane on Antarctica today is higher than during the PETM. The role of methane hydrates in this event is further discussed in a number of papers, such as by Dickens and by Gu et al
  2. Levels of all greenhouse gases (in particular methane) and other climate forcers (such as soot) in the atmosphere are already very high today and rising. The rate at which temperatures are rising today is extremely rapid, even compared with a peak such as the PETM, when global temperatures rose by about 6 °C (11 °F) over a period of approximately 20,000 years.
Today's situation therefore has more potential for methane to accumulate faster in the atmosphere than it can be broken down naturally, threatening to escalate into runaway warming exceeding PETM conditions.

5 comments:

  1. Methane coming through a thick layer of ice is remarkable.

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  2. It does look like a complex destabilization that took a long time to initiate is starting to manifest in surface release of methane above thick Eastern Antarctic ice sheet. But I keep thinking of that finding about higher carbon dioxide levels causing ice to become weaker physically due to the competition for bonding during refreezing particularly at end of crack elongation. An antidote for the changes mankind has initiated to Earth is going to take some doing now..
    Mankind is one heck of a can of work going rancid when it comes to wrecking us.
    There is a meeting on divvying up the Arctic for exploitation happening in Sweden while there is news of hollow cement canisters dropped with poison gas in Syria on civilians and a whole media system and monetary exchange that is nuts..
    I don't know how to bring civilization to bear on taking on this project to save Earth. -What can a person say.. But this is not our world to destroy but to defend. It is our job and knowledge of what's happening wouldn't be made available I'm thinking to the little guy on such important of an issue if it was not still within possibility to make change.. Needed can of worm changes.

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  3. When it looked liked it wasn't coming from the sea I thought of volcanic activity, then for several days I looked for CO2 on IASI and found none. Are there known processes that could absorb CO2 but not methane? And, all this is happening under the ice, half to a mile deep, right?

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  4. "Peak" is a term to be used in a frame of reference where there is a full expectation for a following decline. Otherwise better terms would be "attain", "reach", "hits", etc.

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    1. Yeah, it's always good to try and find the best terms. The graph gives the 'daily peaks', or if you like the highest reading recorded for each day of the period covered by the chart. Since the highest reading ('peak') for the period covered by the chart was 2249 ppb, this was in the title of the post. But an even higher reading was recorded later (of 2266 ppb on August 17, 2013), as described in a more recent post.

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