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Daniel Bailey

Thanks for posting this, Neven. I suppose Agnostic and I will have to do a Son of Kraken article, now.

And I will have to do an updated version of this, part of this overall post.

Fun stuff. Not.


I'll relax a bit if that methane graph doesn't show a spike next year. :-)


Re: "Methane (CH4) contributes about 18% to the overall global increase in radiative forcing since 1750 and is the second most important greenhouse gas after carbon dioxide."

Couldn't work out to post at climate progress that this should be corrected to:

... is the third most important greenhouse gas after water vapour and carbon dioxide. However, water vapour is far more of a feedback than a forcing so methane is the second most important greenhouse gas forcing.

(Yes this is bowing to septics demands for accuracy but it also shows their objections to be meaningless argument for the sake of trying to show that there is argument.)


Re: I'll relax a bit if that methane graph doesn't show a spike next year. :-)

What if there is no spike next year but there is another report of further increase in rate of release?


Well, if I've understood correctly, global methane concentrations are measured pretty accurately. So a serious increase in the rate of release of Arctic methane (and permafrost) should show up there sooner or later, as a spike that clearly deviates from the yearly increases witnessed since 2006.

Tell me if I'm wrong, but I believe there aren't any accurate and comprehensive measurements of methane release from within the Arctic circle. It hasn't been properly assessed yet.

That's something to cling on to. And I'm hoping WUWT will pound on it.

Nick Barnes

I can't find anything by Semiletov in the AGU program. But the search tool there is terrible. Can anyone find some actual data?


I did strike me as odd that no one reported on this on a blog somewhere if Semiletov did present his results at AGU. I mean, this is pretty hot stuff on the AGW front.

Climate Changes

"I did strike me as odd that no one reported on this on a blog somewhere if Semiletov did present his results at AGU. I mean, this is pretty hot stuff on the AGW front.


Maybe because Dr Semiletov released his findings for the first time last week at the American Geophysical Union meeting in San Francisco and that coincided with Durban?

Kevin McKinney

"Spike. . ."

I think what Crandles means is that if emissions continue to be high, it's not a 'spike,' since 'spikes' are by definition transient on the relevant timescale.

I sure hope his speculation doesn't come true, or a lot of stomachs will be doing flip-flops--and that will just be the beginning. But then again, why *should* the emissions decrease?

[Crosses fingers.]


Interesting times... I wonder what's going to hit first...runaway deflationary economic depression or this AGW methane suffocation. By the way, it may be this Independent article put some facts in the mixer. I found on Grist 19 december 2008 a remark about Semiletov speaking on an AGU occasion.


>"So a serious increase in the rate of release of Arctic methane (and permafrost) should show up there sooner or later, as a spike that clearly deviates from the yearly increases witnessed since 2006."

If it doesn't show as an upward acceleration in atmospheric methane levels(or a spike) then maybe it isn't serious yet ..... but if the rate of release keeps increasing it will surely become serious sometime.

Yes, that's pretty similar to what Kevin said. In part I am saying it seems good news that it isn't serious yet but the bit to worry about is the possibility of continuing increases in the rate of release of methane.

>"why *should* the emissions decrease?"

Surely that depends on how much there is in places that are close to becoming unstable. Water temperatures haven't increased much yet and will continue to warm for centuries. If we are lucky there isn't much close to instability, then what is being released is just a few lucky strikes and there is so little close to instability that the lucky streak cannot continue. That does seem to be extremely on the wishful thinking side though.


On realclimate

Anonymous Coward says:
"I’m not sure methane alarmism is in-topic but there’s been two posts in this thread already. Since there’s no official reply, I’ll opine…

Newspapers frequently give ludicrous titles to their articles and usually fail to provide context.
The artcle talk about speculation with regards to hundreds of millions of tons of that “deadly” gas which they figure is 20 times stronger as a GHG than CO2 (that number is arbitrary). Well, I reckon it would take not hundreds but something like 2500 megatons to get 1 more ppm of methane. And methane is short lived so you’d need hundreds of extra megatons yearly to maintain that extra ppm.
People can speculate about how foreboding the methane releases observed by Dr Semiletov are. It makes for good doomer p0rn. But CO2 is a much bigger problem than the methane releases which have been observed so far. People have no notion of how much fossil fuels are burned on this planet."

So maybe slow steady increases in rate of release of methane may not be a worry for some time but rapid further increases would.

Though current levels of methane are at about 1.8ppmv so a 1ppm increase would be a substantial effect.

Daniel Bailey

@ crandles

"Surely that depends on how much there is in places that are close to becoming unstable."
The fact that there are demonstrated areas once formerly ice-covered now ice-free & bubbling like those described tells much about the hydrate stability zones in the area under discussion.

"Water temperatures haven't increased much yet and will continue to warm for centuries."
All the more reason to be concerned if we are already observing significant releases...which we are.

"If we are lucky there isn't much close to instability, then what is being released is just a few lucky strikes and there is so little close to instability that the lucky streak cannot continue."
Quite a bit to hang the future of mankind on: the hope of being lucky.

"That does seem to be extremely on the wishful thinking side though."
If indeed a methane clathrate release has been initiated then wishful thinking may be our only recourse.


Just another Oh $#!+. moment like all the others. Yawn. Or not.

Am I right in thinking that the time lapse between these adrenaline shots is shrinking?

Aaron Lewis

Our analysis of CH4 in the atmosphere is precise, but our sampling array is sparse, and the sampling frequency is poor.

As a result, what our sampling shows are "out-liars". These have been showing up at the Arctic stations for some time. The scary part is last summer's outliers in the Azores data.

Nobody wants to believe it, so everybody seems to be assuming that it is bad data. However, the areas of sea ice formation, and hence the locations of brine rejection and deep water formation have moved. I would not be surprised if some parts of the deep North Atlantic had warmed in the last 50 years.


Wonder if the 2004 Earthquake broke something?

See how the Methane curve starts going up more after 2004?

We also had the Japan earthquake, big suckers.

Maybe they broke open some methane volcanos or something.

Since Methane is so much more powerful, why not burn the methane to make it into CO2, so at least it would have a weaker long-term effect?

Daniel Bailey

@ D

"Since Methane is so much more powerful, why not burn the methane to make it into CO2, so at least it would have a weaker long-term effect?"

If only it were so easy as that. But consider that, during its short 10-year half-life, methane (CH4) has an effective warming potential of 70 times that of carbon dioxide (CO2). THEN CH4 reacts with the OH radical to form CO2. Which is effectively forever on human scales (ten thousand years after being released, 10% of CO2 emissions will still be around doing their 24/7/365 day thing, warming the atmosphere.

So, if energy to "burn" the CH4 were freely available and free resources were also available to bring that energy on-site to the release points of the CH4 releases, then CH4 could be "burned". But the catalytic reactions I'm aware of involve CO2 as a byproduct. So there would be little net gain that I'm aware of (or even a possible net loss).

Permamelt (melting permafrost releasing CO2 and other GHGs) and clathrate/hydrate decomposition in the Arctic is here to stay, courtesy of the massive bolus of long-sequestered, fossil-fuel-derived GHGs that mankind has injected back into the carbon cycle.

Mankind has set forces into motion that cannot be undone. A modern Pandora's Box of consequences, if you will.

Artful Dodger

AGU Fall Meeting THURSDAY, DECEMBER 08, 2011

GC41B-0794. Ebullition-driven fluxes of methane from shallow hot spots suggest significant under-estimation of annual emission from the East Siberian Arctic Shelf

Natalia E. Shakhova; Igor P. Semiletov; Anatoly Salyuk; Chris Stubbs; Denis Kosmach; Orjan Gustafsson

Abstract follows in next comment...

Artful Dodger


TITLE: Ebullition-driven fluxes of methane from shallow hot spots suggest significant under-estimation of annual emission from the East Siberian Arctic Shelf


SESSION TITLE: GC41B. Permafrost and Methane: Monitoring and Modeling Fluxes of Water and Methane Associated With Arctic Changing Permafrost and Coastal Regiona I Posters

AUTHORS (FIRST NAME, LAST NAME): Natalia E Shakhova1, 2, Igor Peter Semiletov1, 2, Anatoly Salyuk2, Chris Stubbs3, Denis Kosmach2, Orjan Gustafsson4

INSTITUTIONS (ALL): 1. IARC, Univerrsity Alaska Fairbanks, Fairbanks, AK, United States.
2. Laboratory of Arctic Research, Pacific Oceanological Institute FEBRAS, Vladivostok, Russian Federation.
3. University of California, Marine Science Institute, Santa Barbara, CA, United States.
4. Institute of Applied Environmental Research, Stockholm University, Stockholm, Sweden.

Title of Team:

ABSTRACT BODY: The high-latitude, shallow ESAS has been alternately subaerial and inundated with seawater during glacial and interglacial periods respectively. Subaerial conditions foster the formation of permafrost and associated hydrate deposits whereas inundation with relatively warm seawater destabilizes the permafrost and hydrates. Our measurements of CH4 in 1994-2000 and 2003-2010 over ESAS demonstrate the system to be in a destabilization period. First estimates of ESAS methane emissions indicated the current atmospheric budget, which arises from gradual diffusion and ebullition, was on par with estimates of methane emissions from the entire World Ocean (≈8 Tg-CH4). Large transient emissions remained to be assessed; yet initial data suggested that component could increase significantly annual emissions. New data obtained in 2008-2010 show that contribution of ebullition-driven CH4 fluxes from shallow hot spots alone could multiply previously reported annual emission from the entire ESAS.

KEYWORDS: [0330] ATMOSPHERIC COMPOSITION AND STRUCTURE / Geochemical cycles, [0312] ATMOSPHERIC COMPOSITION AND STRUCTURE / Air/sea constituent fluxes, [0428] BIOGEOSCIENCES / Carbon cycling, [4219] OCEANOGRAPHY: GENERAL / Continental shelf and slope processes.

SPONSOR NAME: Natalia Shakhova


Hi all,

Lots more information on this currently being posted up @


Also, this may be just me, but isn't it actually quite funny?

It's not all over 'til the fat lady really lets one rip...


Hi again,

I seem to have formatted that link wrong. A Google search for "climate change next generation" gets you to the right site; There are several posts up there that are on topic.

Al Rodger

There's a report on Shakhova's methane findings from 2009(?) linked below which explains the eastern Siberian Arctic shelf.
She gives a rate of emission at 7 million tonnes pa. The Arctic atmosphere methane level is also quantified against global levels – normally 8 – 10% above average global. Shakhova was finding 5 – 10% above that again. (The second link is to images posted 2005 showing surface &, very colourfully, stratospheric methane levels as modelled by NASA.

Shakhova describes the size of the reservoir of shallow methane (presumably 'in the Arctic but mostly on the ESAS'. Shallow is bad because deep can be absorbed in the ocean waters.) thus - “The release to the atmosphere of only one percent of the methane assumed to be stored in shallow hydrate deposits might alter the current atmospheric burden of methane up to 3 to 4 times,” Shakhova said. “The climatic consequences of this are hard to predict.” If I read that right (but don't quote me), that would be a forcing of about 1.5W/sq m, about the same as the net anthropogenic forcing we've achieved already!

Finally, that Hank Roberts has been digging again & has just posted a RealClimate link to a paper (abstract & thumbnail figures) on historic methane levels 1000-1800. It says their data (ice core) even pick up a dip in methane caused by the plague (& “war” but I'm not sure why the conquests of Gengist Khan & the US war of independence would leave such large signatures while wars with proper names like the Wars of the Roses or the 30 Years War have no signature at all).

Shakhova report.
Global methane images.
Methane levels 1000-1800.


Hi all,

There is a new .org to me @


Climatechangepsychology provides a link to a leaflet they have produced with much more information direct from Semiletov, and some very excellent graphs from wipneus and L Hamilton.

Their website appears to have a dozen or so relevent pages, and numerous links to other resources.

Semiletov, Shakhova and Peter Wadhams of Cambridge all appear to be on board with them in some capacity.

They seem very gung-ho about various geo-engineering schemes for the Arctic, with the specific aim of provoking a recovery in the Arctic Sea Ice.


One contributor to the Arctic Sea Ice Blog, meanwhile, has fitted exponential curves to data on ice volume and projected forward to get a date of 2015 for the complete loss of late-summer sea ice.


You have made it into New Scientist!

But Id really hold the old horses on the methane. This could\ may have been going on for years. Its not really changing the global methane levels. It needs the heat to get from the surface to the deeper parts of the sea to melt the permafrost and that is not going to be a quick thing other than places where the currents\ overturning take the energy there directly.

It still strongly feel its a longer term problem. Happy for people to say they think I am wrong by 50 meters or whatever of water will not warm instantly. Least of all when you have 6 months of no sunlight.


Hi all,

That link again:



Artful Dodger

Dolormin: this is academic-speak for we're-checking-to-make-sure-this-shit-is-right...

"Large transient emissions remained to be assessed; yet initial data suggested that component could increase significantly annual emissions."

It should not be read as don't-worry, be-happy.

Daniel Bailey

From the Mitchell et al 2011 paper Al links above:

Egads, yet another hockey stick!


The impacts page of that arctic methane emergency group website starts with

"Without stopping it, sooner or later, one way or another, the loss of the Arctic summer sea ice would lead to runaway global warming"

Note the "would" not 'may'. What do they back up this extraordinary statement with? A couple of quotes suggesting there is albedo feedback and 'may' be carbon or methane releases. The 'may' is immediately converted to "(already happening)" and they seem to think it is job done.

Yes, they have provided evidence for feedback but "runaway global warming"? I don't see the evidence for that.


Dorlomin: "It needs the heat to get from the surface to the deeper parts of the sea to melt the permafrost and that is not going to be a quick thing other than places where the currents\ overturning take the energy there directly."

But in the Laptev Sea, heat doesn't get from the surface to the deeper parts. The Laptev has three layers, cold-warm-cold, with the main injection of heat being not top to bottom but the middle layer bringing heat from west to east (from the Atlantic). It takes about 2-3 years for heat from the Svalbard area to penetrate fully into the Laptev.

The Sea is deep in the north, but on the shelf (shown in Neven's original post), depths average 50m or less. While methane hydrates are conventionally seen as being stabilised by low temperature and high pressure, its pretty evident that with the shallow waters in this case, low temperature has been the key.

I don't think its much of a stretch the possibility that a greater influx of warm water in recent years could easily make the warmer middle layer a bit thicker, warming more of the sea floor directly. Even if the layer is no thicker, it certainly has more heat to dump off into the bottom layer (a slower process, sure, but that bottom layer is pretty thin).

It's a shame that New Scientist article referred only to "a poster". With due regard to Wipneus' excellent graphs, there have been a number of treatments by several posters. Collectively, those discussions address the very objection raised by Axel Schweiger. Once again, NS generates faux conflict to spice up the story instead of reflecting a nuanced position that shows a lot more agreement than otherwise. It's nice to get a nod from a nearly-science magazine, but I suspect it will probably prompt a minor influx of trolls... :-(


Al rodger:

You say 1.5W/m^2...

My God...

Hopefully this isn't as wide spread as they feared.

How long is the delay before a spike in Methane reaches a new thermal equilibrium?

Al Rodger

Having got the figure of 7 million tons methane pa from the ESAS, I was left wondering where I'd find global methane emissions to put the ESAS figure in context.
Where to look? Good old Wikipedia, of course! Annual global methane emissions (natural & human) 600 million tons pa, I'd reckon* two-thirds being human. (*For some reason, Wiki class rice paddies as natural.)


Yeah, but he says in the article it was estimated at 8 million tonnes last year, and then says that based on the new findings, it must be a "significant underestimate".

What does he mean?

Like 50%? a factor of two? an order of magnitude?

How much worse could it be?


Ah, thanks for that, Al. I was looking for some numbers yesterday, but couldn't find any quick enough (must have overlooked those on Wikipedia).

So it's 600 million tons per year, of which approximately two thirds by humans. Most of it gets taken up again or gets converted to CO2, but not all, because global concentration of CH4 is increasing.

According to this latest research by Semiletov "the emissions from the East Siberian Arctic Shelf (ESAS) are much bigger" than 8 million tons of methane.

From Daniel's Kraken article:

It has been known for many years that methane is being emitted from Siberian swamplands hitherto covered by permafrost, trapping an estimated 1,000 billion tons of methane. Permafrost on land is now seasonally melting and with each season melting it at greater depth, ensuring that each year methane venting from this source increases.

Methane clathrate has accumulated over the East Siberian continental shelf where it is covered by sediment and seawater up to 50 meters deep. An estimated 1,400 billion tons of methane is stored in these deposits.

What Shakhova is afraid of, is that all of a sudden 50 billion tons (1000x million) gets released.

I'm just writing all the numbers down for myself.

Idunno, thanks a lot for that link to the Arctic Methane Emergency Group. I have to let that one sink in. I'm looking my fears of the methane bomb straight in the eye! ;-)


I recommend reading the brochure that's featured on the Arctic Methane Emergency Group's (from now on AMEG) website.

More numbers, haven't checked the references yet:

Methane is stored as hydrates in the Arctic and sub-Arctic and in surrounding permafrost. 1672Gt (1Gt = 1 billion tons) of methane is stored under terrestrial permafrost alone, twice the current atmospheric content of carbon [4]. Ongoing observations and analysis forecast a similar amount is held in sub-sea stores. As undersea permafrost thaws it releases the stores of ‘free’ gas (or methane hydrates) hidden beneath it.

A sudden 50Gt release is deemed increasingly “highly possible” [5]. This represents less than 2.5% of the potential 2,200 Gt estimated to be capable of release in the ESAS area. Yet it would increase the burden of methane in the atmosphere by 11 or 12 times. This would cause global warming to speed up by a factor of 4 or 5 times, and the local warming by a much greater factor, resulting in further methane release – a methane feedback. Thus it would almost certainly lead to runaway global warming, with abrupt and catastrophic climate change [6].

Harvey Puca

Here is a Russian research site:



More interesting info:

Dr Semelitov says methane from ESAS is currently entering the atmosphere at a “fantastic rate”, much greater than previous observations. While reported findings from their latest mission to the Arctic won’t be available until Spring 2012, what is to be reported clearly dwarf previous results reported in 2010 [7].

I've been looking some more into AMEG and who's behind it. I'm seeing the names of Semiletov, Shakhova and Peter Wadhams, but they don't seem to be official members of this group.

I've looked some more into the group's chairman, John Nissen, and see his name pop up together with Veli Albert Kallio. I've had some contact with the latter, and he seems like a decent chap, but very much on the alarmist side of things (even more than me if that says anything). I first saw Kallio in this video. he has been calling for measures for quite some time now, because otherwise the Greenland Ice Sheet is going to slide into the oceans and stuff like that. There's a big risk of fiction getting added to science.

I have to go now, but feel slightly more reassured about the immediate urgency of the methane thing (it is urgent, of course). I'll look into it some more later.

Jai Mitchell

your methane data is 12 months out of date. I sure wish that the MLO released methane data that was more real-time.

Al Rodger

Jai Mitchell - Like as not you aim your comment at me. MLO have posted methane concentrations to the end of 2010. They do have provisional 2011 numbers for 9 months which they graph & I scale their graph to extract the numbers & so bring my graph as up-to-date as I can. I don't expect the next update from them for a few months yet.


"...an estimated 1,000 billion tons of methane..."

That's insane...

If that was compressed to the density of water, it would be 1000km^3.

That's actually enough volume to offset a couple years worth of sea level rise!

If this started to go in large chunks, it might even produce seismic activity.

That's a phenomenal amount of soil and water that could be displaced by a sudden release.


Hi D,

1,000 km^3 is the units on the PIOMAS Arctic Ice Volume graphs. So every year, we are witnessing the annual freeze and melt of from around 20,000 km^3 to around 4,000km^3 of surface sea ice.

If the methane is in the form of methane clathrate, then one litre of clathrate contains about 0.8 litres of H2O, and 168 litres of methane gas at surface temp and pressure. I don't know about weight of this, but its clearly pretty dense.

As the seabed freezes, it has apparently frozen mainly as methane clathrate. The energy needed to melt this should, I'm pretty sure, be less than the energy input required to melt ice.

I think that at the moment we are dealing with release by erosion of the clathrate layer in the East Siberian Ice shelf; this is a relatively gradual process.

It also seems to me at least theoretically possible that, as the layer of solid clathrates erodes, this erosion could uncap reserves of already gaseous methane buried below, and, in a fairly-bloody-awful-case scenario, a whole gas field could then vent abruptly into the atmosphere.

Were THAT to happen, amongst other things, it would probably cause a very large tsunami.

A couple of necessary caveats:

1. I am no expert.

2. Even the experts do not have much knowledge of what exactly is lurking on or under the East Siberian Shelf seabed. (But this has been something of a research priority for a few years now.)

I Ballantinegray1

So we go back to the ships Capt.s reports of the ocean surface bubbling "as if it were boiling".

If we are seeing the structures measured in 09'/10' growing by ten times then what of the volume of gas driving these structural alterations? I we have a solid that turns to gas on contact with sea water (growing by 1,000 and more times it's volume) do we not form voids and disrupt the beds above (even if still forming a perfect 'cap' of permafrost?)? Did this year turn the corner from 'localised' chimneys to 'interconnected deposits' with sea water ingress ever deeper into the strata?

Do we see the out-gassing continue over winter? Will it be safe to light a fag on the Sea ice there or would you end up toast?????

Daniel Bailey

Methane hydrate gas releases can cause enormous gas escape features; per Davy et al 2010:

"Multibeam swath bathymetry data from the southwest margin of the Chatham Rise, New Zealand, show gas release features over a region of at least 20,000 km2. Gas escape features, interpreted to be caused by gas hydrate dissociation, include an estimated a) 10 features, 8–11 km in diameter and b) 1,000 features, 1–5 km in diameter, both at 800–1,100 m water depth.

An estimated 10,000 features, ∼150 m in diameter, are observed at 500–700 m water depth. In the latter depth range sub‐bottom profiles show similar gas escape features (pockmarks) at disconformities interpreted to mark past sea‐level low stands. The amount of methane potentially released from hydrates at each of the largest features is ∼7*1012 g.

If the methane from a single event at one 8–11 km scale pockmark reached the atmosphere, it would be equivalent to ∼3% of the current annual global methane released from natural sources into the atmosphere."


[q]Were THAT to happen, amongst other things, it would probably cause a very large tsunami.[/q]

yes, if it was all released simultaneously, it undoubtedly would.

Fortunately, it seems to be "slow motion" right now.

By compressed volume, 1,000km^3 (assuming density similar to water) is the same amount as the volume of ROCK vaporized or ejected in a VEI 8 volcanic eruption.

By mass, it would be about 1/6th to 1/3rd, depending on the rock you compare it to.

So this is truly a colossal amount of material that could be released.

Hopefully it would be very gradual...

But yeah, if big enough bubbles come up, it could generate very large local tsunamis. Locally catastrophic, but probably not far reaching.

Some ship wrecks and plane crashes have been blamed on Methane bubbles in the past, so I guess that's the scale of things you might expect.


Is this a joke?


This seems eerily similar to Isaac Newton's forecast that the world would end in 2060.

Is somebody trolling now?


I believe Sam Carana is from a geoengineering group linked to John Nissen. I read his name over on their yahoogroup.

Is somebody trolling now?

I need to see two more melting seasons, whilst keeping an eye on that global methane concentration graph, before deigning to make a judgment. I don't think the emergency is as urgent as Nissen et al portray it, but that's not really a comfort either.


I'm no expert at all, just some guy with OCD i guess.

I know you know what I discovered in the data, but you just aren't going to say it publicly until a few more years of verification.

That's fine and the professional thing to do, great.

Eureqa agrees with me.

That guy's projection isn't far from what I figured, which is why it scares the hell out of me.

Hope to God it's an anomaly and not the trend, is all I know to say.


HIPPO ended their flights on 9/9, probably before the major plumes Shakhova et al experienced, however interesting observations were made:

The phenomenon also appears very widespread. “We observed that the ocean surface releases methane to the atmosphere all over the whole of the Arctic Ocean,” Wofsy says.



The next paragraph is also interesting:

Climate scientists have been concerned about whether the Arctic Ocean's loss of summer ice cover might lead, through some feedback mechanisms, to boosting the release of methane. Concludes Wofsy: Thanks to HIPPO, “This hypothesized feedback has been observed for the first time.” And there are hints, he adds, that methane’s source may be something other than melting of gas hydrates.


What could that other source be? An increase in microbial life in Arctic waters?


Hi Neven,

Well, it's better out than in, as my old granny used to tell me.

But I feel it could be very counterproductive if this blog becomes totally dominated by methane futurology.

(I realise that I'm as guilty, or more, than anybody else.)

But I'd like to suggest that we could also do with a continuation of the December Open thread, to open above this thread, for ongoing discussions of any other business.

If AMEG, inter alia, are relying on graphs produced by contributors here, let's all keep up the relentless stream of factual, observable, checkable information on the current situation in the far North.

(Oh God, I got drunk in the bath again, and tried to write a speech.)

Wotimeanisthis: I think that the whole issue of the Arctic sea floor methane is desperately serious. BUT...

There is very little data available to us; and there is a very great possibility that we would shed as much light on the issue by continuing to document and debate the surface Arctic Sea Ice phenomena.

For instance: in a couple of places, pursuing this topic, I have read an opinion that a persistent Laptev Sea polyana is potentially caused by methane release.

Is this likely, or not?

As so often, Idunno, and am forced to return again to Neven's Arctic Sea Ice blog, where the bright kids occasionally get round to explaining it to me...


Well, any methane release would probably be or is influenced by what's happening to the Arctic sea ice, so it isn't very far off topic. But I'm not enjoying this discussion at all either.

I still haven't gotten around to writing a blog post on geoengineering, because the idea really doesn't appeal to me. For the same reason I don't like the idea of chemotherapy.

For instance: in a couple of places, pursuing this topic, I have read an opinion that a persistent Laptev Sea polyana is potentially caused by methane release.

Is this likely, or not?

This was in that brochure that was handed out by John Nissen at AGU. I had a look at it and would hardly call it a polynya, after having looked at the week preceding it on the Cryosphere Today comparison page where the image was taken from.

The waters in the Laptev Sea were very warm this year and in my opinion the "polynya" was simply the last place the warm waters were holding out. It froze over within two days after the date on the image in he brochure.

(Oh God, I got drunk in the bath again, and tried to write a speech.)

Do you bathe in whisky? ;-)

I have a nice one for you in the December open thread. Fluke on a graph!

Jeffrey Davis

I don't know why you [D:December 14, 2011 at 19:02] would refer to this as "slow motion". All the reading that I've done says that these releases are faster than those during the large extinction events in our geologic past. Clathrates are stable structures: they're difficult to get at on purpose. (Despite the enormous amount of methane involved, commercial exploitation isn't happening.) It takes a lot to get them to give up the ghost, so to speak.

Kevin O'Neill

Bubbler system have been used to keep ship hulls, docks, locks, and small waterways free of ice. At one time plans were proposed to install a system of bubblers in the main shipping channels of Lake Superior to maintain shipping year-round. I remember news stories from the 1960's and 70's and to prove my memory isn't totally shot I actually found a few online ...

Here's a link to a 1976 Report to Congress, Federal Efforts to Extend Winter Navigation On the Great Lakes And The St Lawrence Seaway

So, bubbles can be used to keep water from freezing, but I think most of these systems use heated bubbles. In the arctic I assume the bubbles would delay freezing, but not prevent it.


Bubblers operate by messing up the thermal stratification of water. What this portends in the Arctic is beyond me, but arctic lakes are known to freeze over trapping methane bubbles beneath the ice. I have no idea if this is because of the shallowness of the lakes or not.

Claudette Bethune

Wasn't something like this that caused the extinction event 250 million years ago? Oh, right: http://science.nasa.gov/science-news/science-at-nasa/2002/28jan_extinction/
With some explanations such as 'a very big asteroid hit the ocean where Antarctica is now (the crater of which they've found), which created a huge shock wave around the Earth coming back to focus in Siberia-to-be, opening enormous lava fields known as the Siberian Traps, but that's not what caused the death of 95% of all life, up to that point it was only equal to the dinosaur killer, but it was just enough worse it caused about 5 degrees Celsius warming, which in turn triggered a sea floor clathrate (frozen methane) melt. That's positive feedback because methane is a greenhouse gas which warmed the world further, spurring more ocean warming, more clathrate melting (with horrible consequences for the sea water too) until finally all available clathrates were gone. Only a few reptile species survived, among which were the common ancestors of dinosaurs and mammals.'

shannon vzix

what are your thoughts on:



If you're asking me, I'm not too sure about anything with regard to this subject. I wouldn't go all-out 'apocalypse now' like some are doing, but I wouldn't go out 'apocalypse not' either.

Like I said, I want keep my eye on the Arctic sea ice as it is pretty much a key factor in this. And I think it's wise to keep an eye on the global CH4 concentration graph in the mid- to long-term, and await the Semiletov results in the short-term (Spring).

I'll re-read the Revkin a piece a few times. I've just started looking into this because before I was afraid. Maybe those fears have no basis. That'd be great.


For instance this from the Revkin piece:

[T]he authors found that roughly 1 meter of the subsurface permafrost thawed in the past 25 years, adding to the 25 meters of already thawed soil. Forecasting the expected future permafrost thaw, the authors found that even under the most extreme climatic scenario tested this thawed soil growth will not exceed 10 meters by 2100 or 50 meters by the turn of the next millennium. The authors note that the bulk of the methane stores in the east Siberian shelf are trapped roughly 200 meters below the seafloor…

1. What is the most extreme climatic scenario? The Arctic free of sea ice in summer 2070? 2050?
2. What are the feedbacks as soil melts? Seabedslides or whatever it is it's called? Non-liquid gas no longer trapped?
3. 10 meters thawed soil by 2100? How big a release of methane are we talking?

You know, it reminds me of the contrarian talking point that it's going to take centuries to millenniums for the WAIS and GIS to melt completely. But that's irrelevant,as it isn't the GIS or WAIS I care about primarily. I'm only interested in the amount of melt that will cause the first 1-2 meters of sea level rise, which would be enough to screw up global infrastructure big time.

Remember: "A sudden 50Gt release is deemed increasingly “highly possible” [5]. This represents less than 2.5% of the potential 2,200 Gt estimated to be capable of release in the ESAS area. Yet it would increase the burden of methane in the atmosphere by 11 or 12 times."


To review, the authors confirm “drastic bottom layer heating over the coastal zone” that they attribute to warming of the Arctic atmosphere, but conclude that “recent climate change cannot produce an immediate response in sub-sea permafrost.” That’s the understatement of the year considering their conclusion that even under sustained heating, the brunt of the sub-sea methane won’t be affected in this millennium.

Can we define 97.5% as the "brunt"? In that case I'd say 'apocalypse perhaps'?

It looks like I'll have to read that paper (I hate that). Too bad Revkin doesn't tell us. He enjoys shouting 'apocalypse not' too much.

Daniel Bailey


"So the next time you see a “science stunner” about Arctic methane time bombs, reach out to a couple of scientists working on this gas before you run to the ramparts."

Like Dr's Natalia Shakhova and Igor Semiletov? The ones actually out there physically measuring and researching the stuff bubbling out of the ocean's surface? And not using just a model? Those guys?

Pardon my skepticism of theory vs practical. And of Revkin in things climate-related. His turn as "honest broker" lapsed long ago.

Mudandwater Mb

We did a blog post on this at MudandWater: http://mudandwater.org/2011/12/14/arctic-scientists-issue-dire-warning-on-methane-clathrates/ Thanks for bringing it to our attention.


From the link in the previous comment:

The Arctic Methane Emergency Working Group is proposing drastic action to deal with this problem including geo-engineering on a massive scale. Proposed solutions include spraying large amounts of aerosols into the atmosphere, cloud brightening, diverting major rivers and blocking the Bering Strait. These approaches could make matters worse in a number of ways, as any major change to the planet’s energy balance will have unforeseen consequences. Even more dangerously, they may lead to the false assumption that we can engineer our way out the problem of global warming. If we are to survive and maintain our eco-systems for future generations, we need to stop treating the planet as a dump.



So the world ends neither in fire, nor ice but in fireice...

Climate Changes

Bubblers would indeed keep water from freezing, or at least would take longer for it to form. A constant stir would make it much harder akin to when birds swim in open pools when lakes freeze keeping them open longer.... and we are talking km wide (and apparently growing) columns.

Regarding Earthquakes, as the methane is released from the freeze it remains trapped underground until disturbed by tremors. This would be like stamping your foot in a boggy area (if any of you has ever done it :P) creates a sudden release of bubbling gas in the surrounds.

Reports and data support the fact of warming in the Arctic at double the global and the ice globally is visibly shrinking fast (just Google Earth any glaciers worldwide to get shocked at the retreat, images from 2010). The Boreal and Artic areas have lost permafrost and therefore it is safe to assume that a lot more gas is waiting to go at a shake.

I do not like the idea of Geo-Engineering myself, nor I look forward to a Blade Runner like sky that Stratospheric sulfate aerosols will bring, if there is a go ahead. However, nothing has changed and we're churnning more GHG's than ever, I'm sorry to be realistic here but even if we could possibly stop polluting today it would take over 100 years to get back to pre-industrial levels of pollutants in the atmosphere, plus we're leaving a legacy of radioactive stuff behind.

We are watching it happen, yet we carry on as we were.

"Stupidity is doing the same thing over and over and expect different results" AE

Jeffrey Davis

re: Revkin

Clathrates are hard to disturb, but I doubt the millenial time scales for methane release that are being referred to. It's like the Lindzen Iris Effect. If the Iris Effect existed, past warming would never have transpired. Similarly, there's strong evidence in the geological record that there have been sudden, catastrophic releases of methane. Something sets them off.

I have to question the scale of consequences that Revkin is being dismissive about. "Oh, no mass extinction. At ease, men. Smoke if you got 'em." Which is absurd. If enough methane is released to add .5C to global mean temps, that's quite enough catastrophe for little Jeff. And if events of our era wipe out huge amounts of life in 3011, and we didn't stop it, all that says is that we're as thoughtless and cruel as a Tamerlane.

Kevin McKinney

If you take Revkin at face value, it's not "Apocalypse not," it's "Apocalypse later." Of course, that would allow a millennium to figure out the needed geo-engineering, but I wouldn't be so cavalier even so.

But does the "subsea permafrost" referred to in the paper Revkin links include clathrates, or is it limited to frozen soil/sediment? If the latter, then we've got an 'apples-to-oranges' issue going. Clarification, anyone?

Finally, it seems to me that we may just need a little more time with the flask measurements to see whether or not CH4 concentrations are sharply up on regional scales. That should tell the tale--but with winter coming on apace, I'm thinking that that may take the better part of a year to evaluate.

I Ballantinegray1

It's really about whether we have time to wait? We still await this years study but the submerged reserves go on degrading even over winter (we still have sea water ingress into the deposits and the physical geographic 're-sculpting' we are seeing. If we have a serious 'breach' in the cap then we cannot stop what occurs next. Nature will follow it's course.
By Sept next year we will have a lot of attention in the area but this is only an attempt to understand what is occuring and not an attempt to halt it. by the time we (as a planet) have enough 'evidence' to sanction action it may be too late?

Daniel Bailey

@ I Ballantinegray1

"by the time we (as a planet) have enough 'evidence' to sanction action it may be too late?"

Pretty much. Once initiated, no force on Earth exists to undo or stop a methane hydrate release as the released CH4 causes further warming which then causes further melting/GHG releases, etc. Kind of like the end of the movie "Total Recall", only more slowly.

"It's really about whether we have time to wait?"

Is it better to presume we have time to wait or to presume we don't? We are talking about an unboundable risk. Given that, is it better to act and be relieved to find out that it wasn't so bad...or to wait only to find out that there was less time than thought?


Re: "no force on Earth exists" from "Pretty much. Once initiated, no force on Earth exists to undo or stop a methane hydrate release as the released CH4 causes further warming which then causes further melting/GHG releases"

On a shorter timescale, once the methane (and any other gasses the methane is converted to) starts bubbling to the surface, would I be correct to assume the water pressure is then less so the hydrate is then more able to release more methane?

The reduced water pressure above, methane passing through cracks and increased buoyancy arising from more space for methane below the cracks is presumably also likely to make existing cracks open wider?

So once a deposit starts leaking some methane, a whole layer is likely to be lost until the remaining methane is all trapped beneath a lower level of ice/permafrost that remains intact?

At this point presumably we have to hope currents tend to bury it to provide some insulation deferring the time when that lower layer melts or fractures?

I think it is guaranteed there is a feedback effect but it is not necessarily a runaway effect. The deposits have to be tremendously large and have lots of them very close to being unstable for the feedback factor to be big enough to start a runaway effect.

Daniel Bailey

The forcing/feedback relationship is not necessarily a runaway effect (nor was it implied to be). At some point a new equilibria will be reached, depending upon the amounts of GHGs vented.

Note that the time to reach a new equilibria is also dependent upon the volumes of GHGs released, due to thermal (and other) lags.

Destabilization of a clathrate deposit means that the deposit will vent until a new pressure/temperature equilibria is reached or until the deposit is depleted. If the deposit destabilizes sufficiently, a blowout could occur (hence my earlier link to Davy et al 2010).

As to the specifics of the pressure/temperature dynamics of stable clathrate/unstable clathrate, that will depend on the local conditions. That we already see kilometer-sized releases testifies that (to some measure) instabilities already exist.

Archer 2007 is a great resource on clathrates/hydrates:


The one and only good point I can see in all this is that the data is out - now.

Which means more work and analysis can be done for inclusion, highlighting, underlining, bright red outlining and all caps presentation in the next IPCC report. It won't be an item that various countries can argue, fuss and obscure around timescales - it's now. So the message should be pretty unequivocal.



What data?

All I saw were anecdotal statements indicating it was significantly worse than they thought, but they never clarified just how much worse.

I would assume that a fountain that has 10 times the diameter would have 100 times the flow rate in volume, based on obvious formula of a circle.

But they didn't really specify that.

Has there been any atmospheric data since this was published to verify a methane plume or something?

Al Rodger

A paper in the Journal of Geophysicial Research by Dmitrenko et al. Recent changes in shelf hydrography in the Siberian Arctic: Potential for subsea permafrost instability
They conclude the methane emissions from the present bottom warming (2.1 deg C since 1980) would not have appeared yet. They reckon that it would be centuries. (Abstract & figures at link below.)


The link was gleaned from CarbonBrief where there are a few other useful-looking links/quotes.


Wayne Kernochan

@Al Rodger: just from a brief glance at the second blog post, it appears clear that they cherry-picked their data/quotes. One would not expect effects from rapid methane melting in the last 30-40 thousand years (and the last 800,000) as this would be the Milankovitch cycle superimposed on "usual" levels of carbon in the atmosphere. In other words, nothing like the PETM. In fact, right now we have almost certainly reached about 1 degree F more warming than any Milankovitch peak in the last 5 million years. Moreover, they ignore Caldeira's tantalizing comment that 55 million years ago during the PETM, there was far less methane stored than there is now. Then they cite Mauna Loa as saying methane levels are flat, when a graphic on this blog shows that they have resumed their climb since 2006, and the best theory is that this is at least partly because of increased methane emissions in the arctic. The "wetlands methane" discussion is a complete red herring: this just says that there's lots of methane in peat bogs, in addition to lots of methane in permafrost and clathrates, and that peat-bog methane can vent at the peak of the Milankovitch cycle even when permafrost and clathrates don't melt. Well, duh.

And let's not forget that the paper cited by the Russian researcher was in 2010, before they went out and discovered far more activity than they expected. Does anyone really believe that the 2010 estimate is still valid? One way or another, the most likely estimate of present-day methane emissions from the total those three sources has to go up in a major way.


Has there been any atmospheric data since this was published to verify a methane plume or something?

Adelady, if I've understood correctly the results will be published by Semiletov in Spring. According to Al Rodger, who produces the graph of global CH4 concentrations at the end of the post, data for this graph (from Mauna Loa) are updated every few months.

Meanwhile, Robert from the Idiot Tracker had a balanced look at Revkin's piece. If he's right, Revkin made a little fail. I agree with Robert's conclusion.

Aaron Lewis

The areas of concern are shallow enough to have been "wetlands" during glacial periods (lower sea level). Hence, they were the kind of place that would have released methane. Then, as they warmed, they became peat lands, formed permafrost, and the rising sea level covered them. This suggests methane gas under a permafrost cap.

ESS is a shallow water area. It did/does not take long for cold brine from sea ice formation to reach and cool the bottom, and the bottom is within reach of "storm mixing" by very local cyclonic storms driven by the temperature difference between sea ice and open water. The ESS is not the stable environment of the deep ocean.

And, if there is methane gas under a permafrost lid, the permafrost does not have to melt, it only has to warm and weaken or change volume (change from one kind of ice to another). In this range of temperatures and pressures, the behavior of ice is very complex. The heat required is small, and could even be carried by the underlying gas from geothermal sources (if there was less cooling from cold brine). Plumes this large from clathrates would have brought chunks of clathrates to the surface. My current thought is that the current plumes are methane gas seeping through cracks in a permafrost cap.


David Appell also has a short post up. Andy Revkin replies to TheTracker, and so I've also weighed in with a question wrt to the "brunt of the sub-sea methane".

Chris Reynolds

I've been busy so haven't had the time to read this thread - maybe over Christmas.

I've been getting my act together for a post about Arctic methane. In doing so I've been looking at some of the data. Here's a nugget that might interest people, possibly be of some use.


That image is a plot of C12/C13 ratios in per mil by lattitude bands, actually for the Southern hemisphere it's rather meaningless as there's only one station per band. When work dies down I may get a chance to seriously try to make sense of it. Here are my musings at present:

The deviation due to a reduction in C13 is because kinematically organic processes 'prefer' C12 to C13, so become depleted in C13. This sort of downward deviation is what one would see if clathrate decomposition were occurring on a large scale, however it's also a signaure of land CH4 emissions from melting pemafrost, or any organic source. (If I'm wrong here correct me)

Re the early rise in C12/C13 - don't know what was causing that. Summer 1998 was very warm in the Arctic and Siberia (GISS maps), 1999 less so (cold anomaly in part of siberia), so temperature might explain the large swings in those years. After that there's a notable dip after 2007, with 2007 itself showing a very large excursion: Summer 2007 was warm in the Arctic but not substantially so compared to years around then, i.e. the largest warming was assoicated with open ocean in Beaufort/Chucki etc. Can a careful examination of summer temperatures and sea temperatures help identify the culprit?

I've a couple of papers looking at the recent resumption in CH4 rise. But they're a bit dated - which is to say that I suspect the Arctic as being responsible for the rise but one of the papers looking at only 2007 - 2009 also cites the tropics. Over a short time period you'll get various regions of the globe playing a role due to fluctuations in regional emissions. But we're now in 2011, with 5 boreal summers since 2007's, the increase continuing, so looking over that whole period might help to 'average' out regional fluctuations. The graph I linked to above suggests that much of the variation in C12/C13 is being driven by large varaition in the Arctic.

I know it's better practice to seek ways to disprove a hypothesis, but I'm still at the early stage of trying to see if the hypothesis is worth stating - that the increase in CH4 emissions since 2007 is predominantly due to the Arctic's responding to 2007 and it's aftermath.


Re Neven's brunt question to Andy Revkin.

Why isn't this already answered?

If we take Revkin's quote and some estimates like 1800Gt of methane (average of 1400 and 2200) and if the majority is below 200m of perafrost of which only 10m is going to melt by 2100. My reaction is to guess 600gt in top 200 meters and spread that evenly amongst the 200m to suggest that only 10/200 * 600 Gt will be released by 2100. That is only 30Gt by 2100 and it is unlikely that is going to be released in one large release. It looks more like an average of .33Gt per year. That makes it hard to rule out a 1 or 2 Gt release in a year but a 50Gt does sound unlikely.

A 50% increase in atmospheric methane wouldn't be good news but it isn't on the same scale as a 50Gt release.


1 or 2 Gt is 2-3 times more than now (600 million tons). I don't know what that would do to the methane forcing, currently 0.5 W/m2.

Chris R, give a shout when you post that Arctic methane post. :-)

Artful Dodger

Hi Adelady,

The Authors of the upcoming paper on E. Siberian Sea methane emissions will have to scoot to have their paper considered for the IPCC AR5 report, due out in Oct 2014.

The approx. cut off date for submitting papers for peer review is about 31 Jul 2012 for Working Group I:


Those papers need to be published or accepted by about 15 Mar 2013 to be included in AR5.

A tight schedule, but the Authors look to be on track to be included, or at least to be considered.

Artful Dodger

Methane (CH4) insitu measurements from Barrow, AK (brw) and Mauna Loa, Hi (mlo) are available via ftp. An index page is on the web, here:


Just as a quick example, Dec 2010 methane levels were 5% higher at Barrow vs Mauna Loa. Anyone care to create a cycle plot?



FWIW my 50% increase stated it was of atmospheric methane level. AIUI the 600 million tons is an emission level not the atmospheric level.

(I could have done my sums wrong. Atmosphere weighs 5*10^18kg, methane = 1.8ppmv .... so how many Gt of methane to 1 ppmv?)

Do we know the W/m2 of a doubling of methane levels?



There is a couple of readings in Barrow approaching 2200 nmol/mol. Last time we saw something like this it turned out to be a leak in the apparatus so probably shouldn't get too excited about this.


If there was a big increase in methane level would this accelerate the removal of methane or would sinks be overwhelmed or would there be little change to the time in atmosphere of about 12 +/-3 years?

Artful Dodger

Here is the CH4 trend at Barrow. From 1780 ppb in 1986 to 1900 ppb in 2011:


I was looking at

(same thing with more unreliable points)


Why not immediately do the test again if you had a data point that far out of the normal?

Of course, the data point should be kept for completionist sake, but If I was checking an instrument and found a data that far out of expected range, it would get tested and re-tested.

Check the instrument, check for human error, re-take the sample and check it again.

Steve Bloom

Hmm, email the folks in charge and ask about those readings?

And what about the other Arctic stations (IIRC Svalbard at least)?

Steve Bloom

Also, I lost track of it and don't have time to look for ir just now, but speaking of Svalbard IIRC there was a paper a few months back finding increased clathrate emissions there, I think on the western shelf margin and attributed to a warming current from the south.


Hi all,

This may belong on the open thread, but seems vaguely relevent here.

The Russians are beginning to drill for oil in the Barents Sea; a good article with lots of information on Russian perspectives on the oil reserves and the Northern Sea Route, etc...


Simultaneously, the news wires are reporting that a Russian rig in the Sea of Okotsch has capsized, with the loss of many hands.


>"it would get tested and re-tested. Check the instrument, check for human error, re-take the sample and check it again."

Ideally yes, but all this takes time and there are only a couple of such plots. Knowing the readings from next 2 or 3 may help you know where to look. If all are too high look for leak in apparatus; if a one off then do measurement again. Using other apparatus might take some time to assemble even if they do have spares to hand ....

>"Hmm, email the folks in charge and ask about those readings?

And what about the other Arctic stations (IIRC Svalbard at least)?"

Alert and Svalbard do not show any recent spikes. I think in highest probability first order the possible causes are equipment failure, human error in carrying out measurement, and local source of methane. None of those would see a spike at other stations. An upturn at all stations would likely take longer to start to appear.

email - things take time and I am sure they know what needs to be done better than I do. So I am thinking leave it to them until the New Year before pointlessly bothering them.

Yvan Dutil

I checked the data from Barrow. Many indicator are anomalous: CH4, CO2, H2, isotopic ratio. This looks suspicious for me.

By the way, you need to check the last to year otherwise the anomalous data point get hidden behind the NOAA logo :)

L. Hamilton

Anyone care to create a cycle plot?

I haven't seen one before, but it's Sunday morning, sunny and cold here, guitars on the stereo, here's a cycle plot of Barrow and Mauna Loa methane 1986-2010:



It is easier for methane to leak than CO2 and there is a more pronounced effect. However, H2 should leak more easily but the anomaly is a drop in H2. To me this suggests the leak is more likely to be at the top of their equipment so H2 leaks out of sample but when methane is removed, some small molecules are leaking into the sample.

Probably need more data to be sure about knowing where to look though.


Hi all,

A recent piece of research on the Laptev Sea finds that bottom water was 3°C warmer than usual in 2007. The following link is relatively unlikely to take you to the right page. You're probably best to wait until I realise I've messed it up and post the right one later... Here goes...


I think we've already speculated above that, once it starts, methane emissions might churn up the various water strata.

I have also been wondering if the release of methane could actually affect weather patterns - not perhaps generally, but methane is lighter than air and should therefore rise through air as its does through water.

Is is remotely feasible that the release of methane over the winter of 2010-2011 helped in any way to the deformation of the troposhere, which in turn was blamed for stratospheric ozone loss in the past winter?

I wouldn't have a clue where to start with this, so if anybody can tell me that the quantities involved are wrong by several orders of magnitude...


I wouldn't know the magniture needed but why would 2010's 16 parts per billion increase be more significant than 2008's 17 ppb increase or 2007's 17 ppb increase or ....

(2009 had a reduction per ftp://ftp.cmdl.noaa.gov/ccg/ch4/in-situ/brw/ch4_brw_surface-insitu_1_ccgg_month.txt )

Rich and Mike Island

Artful Dodger, I am curious as to why methane's increase in the atmosphere slowed down between 1995 and 2005, and since then has been increasing again. Does anyone know what caused that pause?


Could the slowdown be related to the collapse of the USSR?

Timothy Chase

D wrote:

Some ship wrecks and plane crashes have been blamed on Methane bubbles in the past, so I guess that's the scale of things you might expect.

Have you heard of Storegga?

The Storegga Submarine Landslide - and Tsunami
Wednesday, September 24, 2008

Not arguing that this could take place today, and it has been the subject of some debate, but it is thought by many that methane hydrates contributed to a submarine landslide off the coast of Norway about 8000 years ago. The result of the landslide was a megatsunami that hit the coasts of Shetland with waves that may have exceeded 20 meters.

Please see:

In this article, we demonstrate that at the Shetland Islands between Norway and Scotland (Figure 1), this tsunami reached onshore heights at least 20 m above the sea level of that time."

Bondevik, Stein; Dawson, Sue; Dawson, Alastair; Lohne, Oystein (5 August 2003) Record-breaking Height for 8000-Year Old Tsunami in the North Atlanic,
Eos,Vol. 84, No. 31

It has also been suggested that in keeping with the clathrate gun hypothesis, the methane release may have precipitated the warming of the Holocene. Whether what initiated the landslide was earthquakes or the methane itself, the sudden reduction in pressure would likely have triggered a massive release of methane that would have contributed to the landslide. But there are still a number of open questions.

We know for example that the Storegga region is rich in methane hydrates, but not the region where the landslide took place, at least not today. However, the sudden release in pressure may have been enough to use up all of the methane hydrate in the vicinity. It has also been suggested that the landslide and consequent megatsunami took place hundreds of years earlier than the warming that began the Holocene. But it continues to be a matter of some debate.


Hi Timothy,

While I would concur that there may be some connection between the Storegga event and methane hydrates, it is also important to note that the Storegga megatsunami was certainly largely caused by a large chunk of the seabed falling off a (submarine) cliff.

There seems little danger of this happening on the East Siberian Arctic Shelf, which is shallow and flat.

Comment 100 - thread continues over page.

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