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I need some further figures on this to make sense of it all.

We know in that region a rough level of emissions, but what I'd like to know is transport mechanism for the methane at high latitudes and what net increase upon global ppb concentrations (and by extenuation, what net radiative forcing this might add over the short-medium term). I never covered methane in great detail during my studies, but isn't its lifetime around 12 years in the atmosphere? So I am wondering at how this interplays with other modelling and feedbacks?

Out of the current emissions, what ratio of Methane is (and please correct me when I stray from the correct theory here) is effectively removed by oxidation with reactive elements (e.g. hydroxyl radicals) at the sea-atmosphere boundary and then in the stratosphere and troposphere. I read somewhere that the figures on the impact of chlorine atoms in the ocean upon oxidation of methane is not known exactly.

With all this in mind, what's a fuller picture of methane bursts such as that described in this news item?

There was a 'perspective' in Science last year which referred to previous work (http://www.sciencemag.org/content/327/5970/1246.short) of Igor Semiletov where he was a co-author, as well as other studies, about recent findings on ocean emissions of methane.

"How important are these fluxes in the global methane cycle? Considering the global emissions of ∼440 Tg C as methane per year (1), the Siberian Arctic Ocean emissions and the changes in northern wetland emissions are negligible. This is good news, implying that current climate change does not affect the natural methane cycle in a globally important way. But will this persist into the future under sustained warming trends? We do not know. Current modelling studies indicate that the climate-methane feedback from wetlands and permafrost will not be catastrophic but that there will be sustained methane leakages from wetlands and permafrost areas in coming decades (8). Keeping track of these leakages is indispensable for quantifying the climate-methane feedback on a global scale"

So what my ultimate question is, as a mere physicist, who has not done much physics in the last two years, and a mere sprinkling of quartenary geology,  what is the sensitivity to the global climate system and models of the reported increases detailed in recent reports here on this forum from various people?

Thank you for your patience!

Best,

Jonathan

Ps. I apologise for the recent glut of typos - blamed squarely on a combination of manflu and being very busy.

On 13 December 2011 19:53, Omega Institute <[log in to unmask]> wrote:
Hullo Forum,
This is Graham Ennis,
one of the scientists who signed the original report, in the Uk, that led to the story, plus the link in to the Russians. Our own report, which is based on the Russians, (Partly) and also UK science, is pretty much the same. it was presented at the recent AGU meeting in San Francisco. The Russians were there.
 
Actually, the real situation is much worse than in both our UK report, and the Russian report. Basicly, we have entered a decisive tipping point for the climate. The methane release is now irreversible, nd will run until it's endpoint, venting huge clouds of Methane into the atmosphere, that will completely dwarf the carbon emissions. WE ARE NOW IN THE FIRST STAGE OF AN IRREVERSIBLE RUNAWAY GREENHOUSE EVENT.
 
it will inevitably lead to an extinction event.
Graham Ennis.
----- Original Message -----
From: [log in to unmask]" href="mailto:[log in to unmask]" target="_blank">Jonathan Ward
To: [log in to unmask]" href="mailto:[log in to unmask]" target="_blank">[log in to unmask]
Sent: Tuesday, December 13, 2011 12:46 PM
Subject: "Shock as retreat of Arctic sea ice releases deadly greenhouse gas"

Of interest to Forumers - does anyone have more information behidn this story?

http://www.independent.co.uk/environment/climate-change/shock-as-retreat-of-arctic-sea-ice-releases-deadly-greenhouse-gas-6276134.html

Dramatic and unprecedented plumes of methane – a greenhouse gas 20 times more potent than carbon dioxide – have been seen bubbling to the surface of the Arctic Ocean by scientists undertaking an extensive survey of the region.

The scale and volume of the methane release has astonished the head of the Russian research team who has been surveying the seabed of the East Siberian Arctic Shelf off northern Russia for nearly 20 years.

In an exclusive interview with The Independent, Igor Semiletov, of the Far Eastern branch of the Russian Academy of Sciences, said that he has never before witnessed the scale and force of the methane being released from beneath the Arctic seabed.

"Earlier we found torch-like structures like this but they were only tens of metres in diameter. This is the first time that we've found continuous, powerful and impressive seeping structures, more than 1,000 metres in diameter. It's amazing," Dr Semiletov said. "I was most impressed by the sheer scale and high density of the plumes. Over a relatively small area we found more than 100, but over a wider area there should be thousands of them."

Scientists estimate that there are hundreds of millions of tonnes of methane gas locked away beneath the Arctic permafrost, which extends from the mainland into the seabed of the relatively shallow sea of the East Siberian Arctic Shelf. One of the greatest fears is that with the disappearance of the Arctic sea-ice in summer, and rapidly rising temperatures across the entire region, which are already melting the Siberian permafrost, the trapped methane could be suddenly released into the atmosphere leading to rapid and severe climate change.

Dr Semiletov's team published a study in 2010 estimating that the methane emissions from this region were about eight million tonnes a year, but the latest expedition suggests this is a significant underestimate of the phenomenon.

In late summer, the Russian research vessel Academician Lavrentiev conducted an extensive survey of about 10,000 square miles of sea off the East Siberian coast. Scientists deployed four highly sensitive instruments, both seismic and acoustic, to monitor the "fountains" or plumes of methane bubbles rising to the sea surface from beneath the seabed.

"In a very small area, less than 10,000 square miles, we have counted more than 100 fountains, or torch-like structures, bubbling through the water column and injected directly into the atmosphere from the seabed," Dr Semiletov said. "We carried out checks at about 115 stationary points and discovered methane fields of a fantastic scale – I think on a scale not seen before. Some plumes were a kilometre or more wide and the emissions went directly into the atmosphere – the concentration was a hundred times higher than normal."

Dr Semiletov released his findings for the first time last week at the American Geophysical Union meeting in San Francisco.


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