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Arctic Methane Outgassing On The East Siberian Shelf: A Primer Plus an Interview with Dr. Natalia Shakhova

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"Arctic Methane Outgassing On The East Siberian Shelf: A Primer Plus an Interview with Dr. Natalia Shakhova"

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Reports of extensive areas of methane — a powerful greenhouse gas — bubbling up through the shallow waters of the East Siberian Arctic Shelf (ESAS) have generated more questions than answers In this double post, Skeptical Science examines the data available to date and then discusses the findings of 2011 with the Dr. Natalia Shakhova from the research team.

Map of the Arctic showing the East Siberian Shelf

Bathymetric map of the Arctic with key features noted and subject area in red.

by John Mason, cross-posted from Skeptical Science

Summary

The research team have located new and large (~1km wide) plumes of outgassing methane, in areas not previously investigated, so this is not necessarily a recent development: at least, there are no previous data from these areas to compare the large plumes with.

That the area has seen warming over a prolonged time since the Holocene transgression and that there has been an additional, sharp recent warming event is well-documented. Whether there is increased outgassing caused by the additional recent warming is an important question that requires urgent investigation, a point indeed made in Shakhova et al’s 2010 paper in Science  – PDF – see last paragraph.

Further work will better constrain known current methane emissions to the atmosphere, currently estimated to be 8 Tg (1 Tg=1 million tonnes) per year. Clearly, because new sources have been identified, the figure is greater than 8Tg but how much so remains to be discovered.  

A large (multi-gigaton) abrupt release event is considered possible, but when is not known. It is important to remember that hydrocarbons, including methane, migrate upwards through the Earth’s crust from their source-rocks due to their low density. Basic oil geology tells us that recoverable oil and gas deposits occur where such upward migration has been blocked by an impermeable barrier (an oil- or gas-trap) such as a salt-dome or anticline including thick impermeable strata such as a clay-bed. In such places, the accumulation can build up to the point where the oil/gas is in an highly pressurised state – hence the “blowouts” that have been recorded over the years in some oilfields.

What Shakhova is suggesting is that if buried gas hydrates destabilise, what could result is accumulations of pressurised methane capped off by permafrost, which because it is degrading might lose its effectiveness as a gas-trap. The same point would, I suggest, apply to non-hydrate derived methane i.e. gas that has remained as gas. What one would likely see in such a scenario would be a strong increase in outgassing, not in one great “burp” at one locality but via multiple pathways up through the defrosted sediment over a wide area.

Background

To understand the goings-on up at the ESAS in context, we need to go back to the time of the last glacial maximum, some 20,000 years ago. Although the climate was cold, much of Siberia remained unglaciated for the simple reason that the climate was also extremely dry: the main area of glaciation was in the Verkhoyansk Range in the east, which rises to nearly 2500m. The low-lying plains of central Siberia saw the development of permafrost – defined as soil that remains at below freezing point for two or more years. The prolonged cold of the last glacial period saw permafrost develop to great depths – over 1000m in places.  Extensive areas of this old permafrost, albeit thinner than at the last glacial maximum, exist at the present day. On land, permafrost occurs several metres below surface, and is overlain by the so-called active layer, soil which seasonally thaws out and in which the Siberian flora grows.

During the last glacial maximum, global sea levels fell by over a hundred metres, with the result that the shallow seas of the ESAS became dry land, which allowed permafrost to develop there. Climate warming in the Holocene melted the big ice sheets in N America and NW Europe, leading to sea level rise and flooding of the ESAS, which once again became an extensive shelf sea, averaging some 45 metres in depth. The incoming seawater raised the temperature of the seawater-seabed interface dramatically so that it is considerably (>10C) warmer today than the annual average temperature over the adjacent land permafrost areas. This warming led to a certain amount of seabed permafrost degradation but until recently the remaining subsea permafrost layer was thought to be relatively stable, acting as a cap or lid to the methane that was expected to be present in and beneath it.

Permafrost degradation and methane release on land are things that most people will be familiar with: footage of people igniting methane on frozen Siberian lakes has been broadcast many times. This is primarily biogenic methane – formed via microbial decay of organic matter such as plant-debris. As permafrost degrades due to the warming climate, the organic matter, trapped in the frozen ground for thousands of years, is freed and bacterial decay rapidly sets in, releasing methane to the atmosphere.

At greater depths in the sedimentary column, methane may exist in a second form, trapped in clathrate molecules. A clathrate is a naturally-occurring chemical substance which consists of one type of molecule forming a cage-like crystalline lattice  – the host – which traps a second type of molecule – the guest. In the case under discussion here, the host is water and the guest is methane, hence the commonly-used term ‘methane hydrate’. Methane hydrate looks just like ice: it is a white, crystalline solid but is only stable at low temperatures and/or high pressures: otherwise it decomposes, liberating its methane content.

Specimen of methane hydrate in marine sediment

Above: methane hydrate forming irregular white masses embedded in the marine sediment of Hydrate Ridge, in the Pacific Ocean off Oregon.

This sensitivity to temperature and pressure means that outside of very deep water environments, methane hydrate typically occurs at considerable depths in the sedimentary column (ref. 1): values of 200-500m beneath surface are commonly cited as being within the ‘gas hydrate stability zone’ (GHSZ). Any deeper than that and temperatures tend to be too high due to the geothermal gradient; any shallower and temperatures are again too high – except, perhaps, where the hydrates are locked-in and kept at low temperatures by extensive, bonded permafrost. Within the GHSZ, methane hydrate occurs as pore-filling cements in coarse-grained sediment such as sand; conversely, in finer-grained sediment such as mud it forms pure masses of irregular shape. Typical concentrations in sandy sediment are a few percent of pore-volume. Estimates of the total amount present globally vary: although some very high values have been suggested, more commonly-cited figures are 10,000 Gt carbon or less. This is still a substantial figure when compared to e.g. estimates of carbon in global coal reserves.

Methane hydrate has been exploited on a limited scale as a fossil fuel. At Messoyakha, in western Siberia, the Soviets extracted methane trapped beneath a dome of permafrost 450m in thickness; at least a third of the resource, exploited over 13 years, was thought to exist as hydrate which was artificially destabilised by pumping hot water and solvents into the wells in order to collect the gas.

Recent observations on the East Siberian Arctic Shelf

That the sea in this area of the Arctic has warmed up significantly should come as no surprise to anybody who has been following the unfolding reductions in sea-ice and other developments in that region. A 2011 paper (ref. 2), citing hydrographic data collected since 1920, reported a dramatic warming of the bottom water layer over the ESAS coastal zone (<10 m depth), since the mid-1980s, of 2.1°C. The warming was attributed to atmospheric changes involving enhanced summer cyclonicity, reduction in ice extent, the consequent lengthening of the summer open-water season and – consequential to that – solar heating of the water column.

Until relatively recently, the subsea permafrost of the ESAS saw little or no attention compared to the onshore permafrost: it was simply assumed that it was unlikely to be a source area for methane because it was all frozen solid. That assumption was turned on its head in 2003 when the first of a series of field expeditions by scientists from the University of Alaska at Fairbanks took place and resulted in an ominous discovery: surface and especially bottom waters were super-saturated with methane, implying that outgassing from the sea-bed was occurring. Further fieldwork went on to discover plumes of methane gas bubbling up to the surface. In deeper waters, methane does not make it all the way up to the atmosphere – it all dissolves in seawater – but over the shallower waters of the ESAS this is not the case. Air sampling surveys over the ESAS revealed great variability in methane levels: against the global background level of 1.85ppm, they were elevated by typically 5-10% up to 1800m in height, with local spikes over gas-productive areas as high as 8ppm. The researchers calculated the annual total methane flux from the ESAS to the atmosphere to be 7.98Tg C-CH4, which in plain English is 10.64 million tonnes of methane per year, a figure similar to what, up until now, was thought to be the methane emissions of the entire world’s oceans (ref. 3). This figure needs to be seen in the context of other sources, however: domestic animals emit about 80 million tonnes a year, for example.

More worryingly though, the same team made estimates of the methane present as free gas and methane hydrate beneath or within the ~1.5 million sq km of the submarine permafrost of the ESAS. The total came to >1000 Gt. The area of this permafrost affected by active fault zones and by open taliks – zones of permafrost that have melted – was stated to be 1-2% and 5-10% of the total area respectively. As such zones are exactly those through which buried methane can escape from under the permafrost, they went on to suggest that up to 50Gt of methane hydrate was at risk of destabilisation leading to “abrupt release at any time” (ref. 4).

That is a colossal figure, when put against annual anthropogenic methane emissions which in 2010 were approximately 275 million tonnes (or 0.275 Gt). Methane is a far more potent greenhouse gas than carbon dioxide – by a factor of 25 (global warming potential as stated in the IPCC AR4) – so that a 50 Gt methane release would be like releasing 40 years’ worth of anthropogenic carbon dioxide emissions (at 2009 emission levels) all at once. However, there are some issues with cranking atmospheric methane levels up in this drastic way.

The first problem is that in none of the glacial-interglacial transitions of the past 400,000 years has a sudden large methane-spike been recorded. Ice-core data instead reveal transitions from 0.4ppm (glacials) to 0.8ppm (interglacials) and back. Such records would tend to suggest that no such releases occurred during this period of geological time despite drastic fluctuations in climate. Does that suggest that large-scale abrupt methane outbursts are rather unlikely? Leading on from that, the second problem is finding a physical mechanism by which such an abrupt release of that magnitude could actually happen: so far, on a subshelf environment where major undersea landslides are unlikely, nobody has proposed a detailed mechanism by which that could happen.

Furthermore, a recent permafrost modeling study (ref. 2) has indicated that permafrost melting lags behind changes in surface temperature: after 25 years of the summer seafloor warming reported above, in the model the upper boundary of the subsea permafrost deepened by only a metre. This is one of the current controversies associated with ESAS research: has the model accurately depicted the actual situation? The team who did the modelling study have attibuted the observed methane outgassing to “degradation of subsea permafrost that is due to the long-lasting warming initiated by permafrost submergence about 8000 years ago rather than from those triggered by recent Arctic climate changes”. Although they accept that severe subsea permafrost degradation will occur in about a thousand years’ time, they see the current degassing as nothing new. Which of these views will turn out to be correct?

Controversy, however, does not invite complacency. Any increased Arctic methane flux, tapping into vast stores of steadily destabilising methane hydrate, has the potential to keep going over a considerable time-period as a response to warmer (and rising) sea temperatures. We certainly do not need any feedbacks that bring additional natural sources of powerful greenhouse gases to the table, yet that is exactly what we risk up in the Siberian Arctic. The big questions that we now need the answers to are for how long has this outgassing been going on, does it appear to be intensifying and how might a colossal and rapid outburst occur. These are among the points we will be raising with the people on the ground and the answers from our interview with Dr Natalia Shakhova, part two of this post, will soon be appearing, here on Skeptical Science. In the meantime, David Archer, who has worked extensively with gas hydrates, looks at some release scenarios over at Realclimate, here and here.

This piece is part one of a two-part series published at Skeptical Science.

Related Climate Progress Posts:

Below is part two.

Part 2: An Interview With Dr. Natalia Shakhova

In December 2011, following a fresh flurry of sometimes conflicting media reports about methane outgassing on the East Siberia Arctic Shelf (ESAS), we decided to go and talk to the people doing the work on the ground. We are pleased to report that Dr Natalia Shakhova (NS below) of the University of Alaska in Fairbanks agreed to be interviewed by the author, on behalf of Skeptical Science, via email. Here are the responses, verbatim, to our questions.

SkS: In your JGR paper from 2010 you state that methane hydrate in Siberia can occur at depths as shallow as 20 m. Have any such remarkably shallow methane hydrate deposits on the ESAS been directly observed/sampled and if so, how could methane hydrate have formed at such depths?

NS: Yes, such shallow hydrates were sampled in Siberia. They form as a result of the so-called “self-preservation phenomenon” and they are termed “metastable”. This phenomenon has been intensively studied by Russian geologists starting in the late 1980s.

SkS: Your 2011 field season is reported to have located kilometre-diameter plumes of outgassing methane. Are these located in areas visited in previous seasons?

NS: These were new sites from that part of the ESAS that was investigated very sparsely before. In our previous investigations we mainly focused on the shallower part of the ESAS, which composes about 70% of the total area and provides a very short conduit for methane to escape to the atmosphere. Besides, because we worked mostly on small vessels, we were not allowed to navigate far enough from the coasts to reach the mid-outer shelf where water is relatively deep on the scale of the shallow ESAS (>50 m depth). That is why deeper waters were under-represented and were considered a minor contributor to annual emissions. Last summer’s findings made us re-consider our previous constraint on the annual emission budget; they highlight the need to further assess underestimated components of annual fluxes from the ESAS.

Searching for methane in such an extensive area is truly like searching for a needle in a haystack. The ESAS is more than 2 million square kilometers in extent.  Even if we study ~10 000 km2 every year (100×100 km, which is a lot!), it will take >200 years to investigate the entire ESAS! Even then, the probability of finding a hot spot 1 km in diameter within the study area will still be only 0.01%.

SkS: Have you done any analyses/isotopic studies of the fugitive gas to see if anything can be learned about its provenance (i.e., biogenic, thermogenic, destabilized hydrate or a combination of these)?

NS: Yes, we conducted an isotopic analysis to obtain the isotopic signature of the methane dissolved in the water column. The isotopic signature indicates a mixture of methane of different origins. We are currently making an effort to investigate particular sources.

SkS: Do the observed methane outgassing sites tend to correlate with features seen on acoustic imaging of the sea bed (e.g. taliks, pock marks, fractures) or on deep seismic data (e.g. fault-zones, anticlines and other structures)?

NS: We believe that methane outgassing sites primarily correlate with features like those you list above.  Our data, although they are still limited, clearly exhibit such a correlation. Unfortunately, there are some limitations in usage of both hydro-acoustic and deep seismic methods imposed by the shallowness of the water column and the ubiquity of shallow gas fronts in the sediments.  In addition, our ability to obtain extensive records was constrained by our limited funds; to date we only have ~3000 nautical miles of such recordings.

SkS: A critical question at this point is whether the outgassing is a recent development as a consequence of the dramatic Arctic warming of the past thirty years, or an ongoing, long-term response to the Holocene inundation of the ESAS. What are your thoughts on this and, on a similar line of enquiry, would it be possible to determine the age of the organic matter the methane was originally derived from?

NS: An entire second paragraph of our paper published in Science (Shakhova et al., 2010) is devoted to addressing this question! We were the ones who hypothesized – and devoted our entire study to testing this hypothesis – that methane release from the Arctic shelf is determined by the change in thermal regime of permafrost inundated thousands of years ago. I do not understand why this question should arise over and over again or, moreover, be considered critical. As we deal with the long-lasting permafrost warming caused by the warming effect of the overlying seawater, is there any logic in negating the contribution of the recent warming, which caused additional warming of that overlaying sea water?  I believe that there is absolutely no point in trying to determine who is responsible, Mother Nature or human beings. Whoever is responsible, the consequences will be the same.

As for determining the age of the organic matter the methane was derived from, it is very hard to distinguish between modern and ancient sources. The mean age of organic matter preserved even in the surface sediments in the ESAS is 6-8 thousand years, and when you go deeper, you find older organic matter. “Talik” is a term used to describe an unfrozen layer of ground within a still-frozen permafrost body.  As taliks develop within the sub-sea permafrost, organic matter of different ages could provide the substrate for methanogenesis. This means that modern methane could be produced from organic matter of different ages, and this is also true of pre-formed methane.

SkS: The recent reports of substantial releases of methane on the ESAS prompt us to ask how these observed emissions could detectably change global atmospheric methane concentrations and in what timeframe?

NS: To date, we have only taken the very first steps down the long path of learning enough to answer this question. We officially reported only 8 Tg of methane was being released from the ESAS per year. This reported amount is <2% of the total annual global methane release and would not detectably change global atmospheric methane concentrations. However, we did not incorporate a few emission components – probably the most important ones – because of some uncertainties still remaining concerning their constraints. Newly obtained data, without question, indicate that annual methane emissions from the ESAS have been underestimated. To say how significant the underestimated components are, and to identify the mechanisms responsible for such substantial releases, we need to carefully analyze obtained data and, very likely, conduct further investigations on a broader scale. To be able to answer your question, which is a core question of our study as well, we need to establish at least a few observatory sites to trace dynamic atmospheric concentrations of methane; we need to develop a monitoring net to detect changes occurring in known plume areas; we also need to continue all-season observations in this region to study temporal and spatial variability in methane releases and the factors that determine this variability. We undoubtedly need to learn much more than we currently know. We call for the involvement of serious funding organizations to give this study the level of support that is consistent with the importance of this topic.

SkS: With respect to future events, in your EGU 2008 abstract it is stated that “we consider release of up to 50Gt of predicted amount of hydrate storage as highly possible for abrupt release at any time”. This represents a colossal quantity of gas. How quickly could such a release occur and what would be the most likely mechanism?

NS: I believe that the non-gradual (massive, abrupt) emission mode exists for a variety of reasons. First, wherever in the World Ocean such methane outgassing releases from decaying hydrates occur, they appear to be torch-like with emission rates that change by orders of magnitude within just a few minutes. Note that there was no additional seal such as permafrost to restrict emissions for hundreds of thousands of years anywhere in the World Ocean. Imagine what quantity of methane has been stored beneath sub-sea permafrost if even now, when the permeability of permafrost is still limited, the amount of methane annually escaping from the ESAS is equal to that escaping from the entire World Ocean. Another important factor is that conversion of hydrates to free gas leads to a significant increase in the gas pressure. This highly-pressurized gas exerts a geological power that creates its own gas migration pathways (so-called “chimneys” within sediments). It is even more important to understand that the nature of the permafrost transition from frozen to unfrozen is such that this physical process is not always gradual: the phase transition itself appears to be a relatively short, abrupt transformation, like opening a valve. Remember that the gas “pipeline” is highly pressurized. There could be several different triggers for massive releases: a seismic or tectonic event, endogenous seismicity caused by sediments subsiding pursuant to hydrate decay, or sediment sliding on the shelf break; the shelf slope is very steep, and the sedimentation rates are among the highest in the ESAS. As for the amount that could possibly be released, this estimate represents only a small fraction of the total amount of methane believed to be stored in the ESAS (3.5% of 1400 Gt). Because these emissions occur from extremely shallow water, methane could reach the atmosphere with almost no alteration; the time scale of such releases would largely depend on the spatial distribution and capacity of the gas migration pathways.

SkS: A previous methane release of such a magnitude, occurring abruptly, would logically manifest as a spike in the global methane concentration record, yet the ice-core methane record has no such spikes during previous interglacials. Is there any evidence for massive methane release events having occurred further back – e.g. at any point during the Cenozoic?

NS: You would better address such a question to a specialist in paleo-climatology. To my knowledge, there are a few episodes in the Earth’s history attributed to abrupt methane releases. Interpretation of ice-core methane records may not be relevant, because these records are too short to reach back to the entire Cenozoic.

Skeptical Science would like to thank Dr Shakhova for her contributions.

Notes

The “self preservation phenomenon” mentioned by Dr Shakhova in her reply to the first question is well-known in Russian and other northern petrochemical industry circles, where much discussion may be found. It is temperature-dependent i.e. it requires fairly low temperatures to work. For more information, see Self-preservation of gas hydrates (PDF) for a briefing.

Summary

The research team have located new and large (~1km wide) plumes of outgassing methane, in areas not previously investigated, so this is not necessarily a recent development: at least, there are no previous data from these areas to compare the large plumes with.

That the area has seen warming over a prolonged time since the Holocene transgression and that there has been an additional, sharp recent warming event is well-documented. Whether there is increased outgassing caused by the additional recent warming is an important question that requires urgent investigation, a point indeed made in Shakhova et al’s 2010 paper in Science  – PDF – see last paragraph.

Further work will better constrain known current methane emissions to the atmosphere, currently estimated to be 8 Tg (1 Tg=1 million tonnes) per year. Clearly, because new sources have been identified, the figure is greater than 8Tg but how much so remains to be discovered.  

A large (multi-gigaton) abrupt release event is considered possible, but when is not known. It is important to remember that hydrocarbons, including methane, migrate upwards through the Earth’s crust from their source-rocks due to their low density. Basic oil geology tells us that recoverable oil and gas deposits occur where such upward migration has been blocked by an impermeable barrier (an oil- or gas-trap) such as a salt-dome or anticline including thick impermeable strata such as a clay-bed. In such places, the accumulation can build up to the point where the oil/gas is in an highly pressurised state – hence the “blowouts” that have been recorded over the years in some oilfields. What Shakhova is suggesting is that if buried gas hydrates destabilise, what could result is accumulations of pressurised methane capped off by permafrost, which because it is degrading might lose its effectiveness as a gas-trap. The same point would, I suggest, apply to non-hydrate derived methane i.e. gas that has remained as gas. What one would likely see in such a scenario would be a strong increase in outgassing, not in one great “burp” at one locality but via multiple pathways up through the defrosted sediment over a wide area.

David Archer, who has worked extensively with gas hydrates, looks at some release scenarios over at Realclimate, here and here.

Some afterthoughts

In February 2002, the then U.S. defence secretary Donald Rumsfeld famously said: “There are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns – there are things we do not know we don’t know.” He was lambasted and ridiculed for this at the time. However, at face value, all politics aside, the statement has more than a ring of truth to it.

My scientific background is in mineralogy, and I hope I may offer an analogy which illustrates what is meant by “known knowns, known unknowns and unknown unknowns”. During the 1980s, I and a number of other mineralogists started to turn up samples of a mineral forming beautiful vivid pale-green spiky crystals. These were found at old metal-mines in Mid-Wales and the English Lake District: first at one locality then another and another. Despite having all the tools of mineral identification at our disposal, including x-ray diffraction and the electron microscope, we could not match it to any known species. Before we started to find specimens, it had lain there in the mine spoil, an unknown unknown, for centuries. Now we had specimens and could study it but not identify it, it was a known unknown. Finally, nearly twenty years after the first discovery, it became a known known – redgillite, named after one of its localities: a basic sulphate of copper with its crystallography and chemistry described in detail in the peer-reviewed journal Mineralogical Magazine.

Redgillite

above: from unknown unknown to known unknown to known known: redgillite, first described in 2004.

I offer this not as an off-topic distraction but as an example of the way in which science proceeds. In almost every case it is the same: only the timescale may vary. Something new is discovered yet is not fully understood. That uncertainty, however, gives pointers towards follow-up work: in time the uncertainties are whittled away one by one and the whole picture becomes clear. It is a journey which will be familiar to anyone working in any of the many branches of academic research. Shakhova and her colleagues have embarked on a journey of challenging proportions: less than a decade ago they discovered what had to that point been an unknown unknown. Now they have described some of the known knowns: we now know without doubt that methane is venting to Earth’s atmosphere from parts of the ESAS seabed in copious quantities as a response – a positive feedback – to warming. Furthermore, they have identified many of the known unknowns for follow-up study. They have rightly called for the setting-up of an observational network in the area and they are planning their research for the coming years in a physically and logistically-challenging area.

Outside of science, people seem to work differently a lot of the time, wanting a black-or-white world where everything is a known known. That there are no absolute, cover-all conclusions yet from the ESAS might come as a disappointment to some. However, this is maybe a time to reflect that, 116 years ago, Arrhenius figured out that adding carbon dioxide to the Earth’s atmosphere would raise Earth’s surface temperature over time. That has been a known known ever since, reinforced by study after study after study, during which time we have raised carbon dioxide levels well beyond anything during the geologically recent glacial-interglacial cycles, so that we are now heading, decade by decade, towards the climate of the mid-Cenozoic,  methane or no methane.

This post was originally published at Skeptical Science.

References

1. Archer, D (2006): Destabilization of methane hydrates: a risk analysis. A Report Prepared for the German Advisory Council on Global Change (40pp). PDF

2. Dmitrenko, I.A., Kirillov, S.A., Tremblay, L.B., Kassens, H., Anisimov, O.A., Lavrov, S.A., Razumov, S.O. & Grigoriev, M.N. (2011): Recent changes in shelf hydrography in the Siberian Arctic: Potential for subsea permafrost instability. Journal of Geophysical Research, 116, C10027. Abstract

3. Shakhova NE, Semiletov I, Salyuk A, Yusupov V, Kosmach D, Gustafsson O (2010): Extensive methane venting to the atmosphere from sediments of the East Siberian Arctic shelf. Science, 327:1246-1250. Abstract

4. Shakhova NE, Semiletov I, Salyuk A, Yusupov V, Kosmach D (2008). Anomalies of methane in the atmosphere over the East Siberian shelf.  Geophysical Research Abstracts 10, EGU2008-A-01526. Abstract

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23 Responses to Arctic Methane Outgassing On The East Siberian Shelf: A Primer Plus an Interview with Dr. Natalia Shakhova

  1. prokaryotes says:

    I compiled an expert discussion, about recent Methane Anomalies

    Latest Methane Anomalies (off the chart) with Expert discussion http://climateforce.net/2012/01/19/latest-methane-anomalies-off-the-chart-with-expert-discussion/

    The article features a video about Snow, Water, Ice, Permafrost in the Arctic (SWIPA)

  2. fj says:

    Despite all appearances of a sick joke regarding what seems complete & utter corruption & ineffectiveness of governance, mainstream media, etc. . . .

    This should be brought before Congress immediately.

  3. Brooks Bridges says:

    I was finding the statement “yet the ice-core methane record has no such spikes during previous interglacials.” at least a little comforting but the thought occurs:

    If such a release triggered major global warming, wouldn’t the warming melt any ice record? Much like not being able to find a murder weapon if an icicle was used. And by the time new ice formed, the methane would have mostly evolved into CO2?

    • prokaryotes says:

      Permafrost in the past

      Progressive cooling of the Earth’s climate, which started about 40 million years ago, caused expansion of the surface area occupied by ice masses and permafrost. Since then, the Earth’s climate has been generally conducive to the existence of permafrost at high latitudes and high elevations in both the Northern Hemisphere and Southern Hemisphere.

      Huge changes in climate and other environmental characteristics including northern hemisphere permafrost distribution occurred across the northern high latitudes during the Pleistocene (roughly the past 1.5 million years; see also Figure 5.3). These changes were driven by the Milankovitch cycles in solar radiation received by the Earth’s surface ..

      ..changes in current permafrost will reflect its history: the first permafrost to begin to thaw will be the youngest Little Ice Age permafrost, followed by mid- and late-Holocene permafrost, and lastly, Late Pleistocene permafrost. (from Chapter 5.2.1.)

      http://amap.no/swipa/CombinedDraft.pdf (80 mb draft SWIPA chapter 5)

      We have ice core records from antarctic for the past 800.00 years, which are in agreement with the relative up/down of the Milankovitch cycles. A major global warming likely have melted those.

      Also there would be a negative excursion in carbon stable isotope (δ13C) records from across the globe, and dissolution of carbonate deposited on all ocean basins. (The latter observations strongly suggest that a massive input of 13C-depleted carbon entered the hydrosphere or atmosphere at the start of the PETM – from PETM wikipedia)

    • jyyh says:

      yep, and the same applies to CO2 if there’s a long period of no snow over the ice sheets. also, i don’t know how well the methane stays as it is even if it’s trapped in the ice.

    • John Mason says:

      Brooks,

      We have a pretty good ice-core stratigraphy going back through the glacials/interglacials i.e. during that time, nothing of such a magnitude appears to have occurred. In addition, methane has a short, ~1 decade atmospheric residency after which oxidation would have left a major uptick in the CO2 trace – above the normal 180-280ppm cycles.

      This really is Terra Incognita that we are heading into here. If the US Congress want to do something useful and quickly, a monitoring network urgently needs to be put in place around this whole area.

  4. Raul M. says:

    Wouldn’t methane if trapped in ice warm just a little of the ice surrounding it and migrate upwards in the ice if sunlight strikes?

  5. prokaryotes says:

    Sidenote, I just preparing a new post about anthropogenic methane of origin. On the bottom line the current natural gas buzz is worse for the climate as coal (with newest assessments). I post the link later. This is big.

  6. Joan Savage says:

    Thanks for the link to “Self-preservation of gas hydrates” by VA Istomin et al (2006) in gasoilpress (RU) that has great graphs though its conclusion may have lost something in translation.

    They wrote, “The self-preservation phenomenon enables gas hydrates to exist in metastable condition for long periods of time, at atmospheric pressure and temperatures below 271 K.”

    In contrast, the graphs suggest that when methane hydrate slips out of very deep cold and/or high pressure, the decomposition can occur in minutes, hours, weeks, a year or two at most. To me that is comparatively quick.

    For companies engaged in gas extraction it might seem slow enough, as the clathrates are less volatile than already gaseous CH4, so that might be the context for the language of the authors’ conclusion.

    A better understanding of the pressure conditions in the Arctic geology as well as it temperature shifts at depth, is really desirable.

    • John Mason says:

      Joan,

      “A better understanding of the pressure conditions in the Arctic geology as well as it temperature shifts at depth, is really desirable.”

      Indeed. I read a stack of papers from the time the first story appeared in the UK Independent newspaper, with the Revkin version coming hot on its heels, both coming to conclusions which the evidence did not actually support, though the conclusions were in complete opposition to one another.

      These guys looking at the ESAS have a lot of work to do, evaluating the possibilities. That’s why I used the Rumsfeld quote, because it does sum this particular situation up well, and because it’s damn time that people give the scientists space in which to do this vital work. The situation up there is potentially dangerous but the big question remains: “how much”.

      Jumping to immediate conclusions would be scientifically careless. Raising awareness of the potential risks is another matter: after all, we all buy insurance yearly as a bet that if something goes horribly wrong, we will at least get a win on the fruit-machine! Compared to the way insurance-companies generally make profits, international support for these guys seems to me a good punt!

      Cheers – John

  7. otter17 says:

    Excellent article, very illuminating. It would be nice to see consistent monitoring buoys at several of the plumes to measure if their methane outgas rates remain stable or increasing very slowly (*fingers crossed*). Is there any way to use one of our Earth-viewing satellites to measure methane concentrations throughout the region? It seems like the current method of manually traveling through the region once a year won’t quite give us the big picture in a timely manner.

    Hopefully our contributed warming to the region has not largely affected the historical outgas rates since the deglaciation, or at least the timescale is long for the feedback to kick in. I communicate with people in my life that the methane from the land permafrost and methane under this Siberian sea are certainly large potential feedbacks, but these feedbacks can be stopped at the source if we cut off the warming that is feeding the feedbacks (CO2 emission reduction targets as laid out by scientists).

    • prokaryotes says:

      A bit more about monitoring..

      On carbon transport and fate in the East Siberian Arctic land–shelf atmosphere system

      The resulting CH 4 emissions to the atmosphere are determined primarily by seasonal features specific to the ESAS such as ice cover, water mixing during storm events, and deep fall convection, rather than by factors influencing the type and the strength of the source. We can conclude that the ESAS accumulates the integrated biogeochemical signal
      produced by terrestrial and marine ecosystems in response to ongoing climate change. To further assess and quantify the contribution of the ESAS to the regional and global carbon cycle, we plan to obtain new data to answer the following overarching questions.

      (1) How does the contribution of the ESAS affect the role of
      the Arctic Ocean in influencing the regional CO 2 balance?
      (2) How do processes of terrestrial OM decay in the ESAS water ontribute to Arctic Ocean acidification?
      (3) How much CH4could be released to the atmosphere from the ESAS due to degradation of sub-sea permafrost and decay of seabed deposits? What is the current state and projected future dynamics of sub-sea permafrost?

      To answer these questions we call for extended international cooperation in studying the ESAS. Such study will require multiple year-round exploration campaigns, including drilling of sub-sea permafrost to evaluate the sediment CH 4 potential and comprehensive atmospheric measurements to assess the ESAS strength as a greenhouse gas source. International effort should also be joined in order to uantitatively assess future changes in greenhouse gas emissions in response to ongoing climate change by establishing and developing regional numerical models with the aim of incorporating them into global climate models. http://iopscience.iop.org/1748-9326/7/1/015201/pdf/1748-9326_7_1_015201.pdf

  8. perceptiventity says:

    No need to worry (: The heating is on but only just next to East Siberean Arctic Shelf

    http://e360.yale.edu/slideshow/nasa_graphic_depicts_significant_spike_in_temperatures_in_2011/54/1/

  9. wili says:

    Hi John Mason,

    I have been very concerned about developments in the Arctic, especially the prospects that a methane feedback may have already started. But I had a question about one sentence in your last paragraph:

    “we now know without doubt that methane is venting to Earth’s atmosphere from parts of the ESAS seabed in copious quantities as a response – a positive feedback – to warming”

    Where in the interview did you derive this conclusion from? Or was it from some other source? In another interview, Shakhova explicitly stated that she had NOT said that these plumes could be shown to have been triggered by recent warming.

    If we do now know for certain that the plumes are in fact part of a feedback, this is indeed reason for a much higher level of concern than if they are either part of a long-term or cyclical release, or if they just a one-time event.

    So I would be very interested in anything you could point out in this interview or link to that helps explain the high level of certainty you seem to have that recent reported methane release in the Arctic Ocean can definitively be linked to GW forcing and is part of a feedback already going on.

    Thanks,
    wili/john harkness

    • prokaryotes says:

      wili, you get this from Shacova’s 2010 studies, which are linked in the summary.

      Sidenote CP should add the related articles…

      Science stunner: Vast East Siberian Arctic Shelf methane stores destabilizing and venting

      The new Science study, led by University of Alaska’s International Arctic Research Centre and the Russian Academy of Sciences, is “Extensive Methane Venting to the Atmosphere from Sediments of the East Siberian Arctic Shelf” (subs. req’d). The must-read National Science Foundation press release (click here), warns “Release of even a fraction of the methane stored in the shelf could trigger abrupt climate warming.” The NSF is normally a very staid organization. If they are worried, everybody should be. http://thinkprogress.org/romm/2010/03/04/205600/science-nsf-tundra-permafrost-methane-east-siberian-arctic-shelf-venting/

      Shakhova et al (2010) reports that the continental shelf of East Central Siberia (ECS), with an area of over 2 million km2, is emitting more methane than all other ocean sources combined. She calculates that methane venting from the ECS is now in the order of 8 million tons per annum and increasing. This equates to ~200 million tons/annum of CO2, more than the combined CO2 emissions of Scandinavia and the Benelux countries in 2007. This methane is likely sourced from non-hydrate methane previously kept in place by thin and now melting permafrost at the sea bed, melting clathrates, or some combination of both.

      Release of ECS methane is already contributing to Arctic amplification resulting in temperature increase exceeding twice the global average. http://thinkprogress.org/romm/2011/04/25/207958/methane-hydrate-feedback/

      • wili says:

        Thanks for that prok, but I really would like to hear what John Mason has to say on these issues, too.

        • John Mason says:

          Wili, I left a comment at SkS but will cross-post it here too:

          Wili,

          In response to your first question, clearly the methane is being released as a feedback to warming. What I was careful NOT to say was to which bit of the warming: that resultant from the Holocene transgression or that heaped upon it by Mankind. At the moment, we don’t know, as Shakhove herself says: the point is we need to evaluate the situation further.

          How one goes about determining whether the post-1980s abrupt seawater warming reported by Dmintrenko et al is causing this effect I don’t know, but I would hazard a guess that should the rate of methane emissions in the coming years be found to be increasing in tune with this extra warming then we should have a pretty good idea, likewise with the ARS data you refer to.

  10. Solar Jim says:

    Some initial responses.

    1) RE: “The first problem is that in none of the glacial-interglacial transitions of the past 400,000 years has a sudden large methane-spike been recorded.” Perhaps this is due to timeline event difference. Human release of over a trillion tons of carbonic acid gas over the past century does not compare with historic records.

    2) RE: “the second problem is finding a physical mechanism by which such an abrupt release of that magnitude could actually happen” What if one of numerous floating atomic fission reactors that Russia is planning to power their Arctic hydrocarbon extraction rigs with were to sink (accidents do happen)? If the control rods were not inserted before submergence, then you might have a hundred tons or so of several thousand degree metal sinking through subsea clathrates. This event might initiate a chain reaction type scenario of cascading feedbacks.

    Methane is one hundred times stronger than carbonic acid gas at radiative forcing. This strength diminishes if reacted with hydroxyl radical, which could be depleted if overwhelmed.

    Thanks very much for the discussion and interview.