Note that the worst case temperature forcing scenario is the most likely Modern Global Warming scenario. In the early 1990s CE, the UN Framework Convention of Climate Change considered “business as usual” as the global warming forcing standard model. In the latter 1990s CE, U.S. and other world leaders masked serious global warming problems by designing UN “climate change” case studies to reflect global warming greenhouse gas increases at less than “business as usual” standard levels. World leader intent was/is to continue “business as usual” expanding of national hydrocarbon economies of COAL, OIL, and NATURAL GAS. Starting in 2005 CE, European-U.S. politicians’ “alternative renewable green energy” became a public and political special interest “clean energy ploy” while world leaders continued to expand hydrocarbon economies and phase out clean nuclear energy.
Since before 2000 CE, politicians and world leaders minimized and manipulated concerns over greenhouse gases. Methane gas reporting in particular was politically minimized. U.S. energy and gas emissions reporting was falsified. International global warming reporting and energy use remains also falsified.
Now Arctic Region carbon and methane is under closer scrutiny by some in the academic profession (but not by the UN Framework Convention of Climate Change or the U.S.). There have been more than two decades of political global warming response delays. The UNFCCC political meeting in Copenhagen, Denmark, December 2009 CE, set global warming responses back additional decade. There is NO U.S. or UN planning or solutions to global warming temperature increase. Without reliable global knowledge, planning, and solutions, all human races terminate 2050-2050 CE.
Primarily due to human and natural greenhouse gas atmospheric density increases, since 1750 CE, there is a resulting global warming temperature increase. The shallow waters of the East Siberian Arctic Shelf (ESAS) and land temperatures responded with temperature increase and more carbon and methane release; a destructive positive regenerative gas release-temperature increase feed back loop is established. More than 60,000 years of Earth greenhouse gas and temperature stabilization is now destabilized.
There are very limited ESAS methane hydrate studies. Note that Polar Region Northwest Passage and Baffin Bay also contain vast shallow methane hydrate (aka, clathrate) deposits that remain unexplored. Venting of Polar Region methane is a huge under identified threat to human races existence. There are no world leader responses to this significant threat.
“Arctic Methane Of The East Siberian Shelf: A Primer Plus an Interview with Dr. Natalia Shakhova”
By Climate Guest Blogger on Jan 19, 2012
Reports of extensive areas of methane — a powerful greenhouse gas — bubbling up through the shallow waters of Russia’s 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.
by John Mason, cross-posted from Skeptical Science
Summary
The research team have located new and large (~0.6mi 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 natural and human global warming transgression and that there has been an additional, sharp recent warming event is well-documented. The increased outgassing caused by the additional recent warming is an important question that requires urgent investigation, a point indeed made in Shakhova et al 2010 paper in Science see -PDF- last paragraph.
Further work will better identify current methane emissions to the atmosphere, currently estimated to be 8 Tg (1 Tg=1 million tonnes) per year. Clearly, because new methane emission sources have been identified, the figure is greater than 8Tg but how much greater remains to be further evaluated and reported.
A large (multi-gigaton) abrupt methane 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 methane 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 methane 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. In Arctic Region and ocean conditions methane gas temperature and pressure are considerations.
What Shakhova is suggesting is that if buried gas methane hydrates destabilise, what could result is accumulations of pressurised methane capped off by land/sea permafrost, which because it is degrading might lose its effectiveness as a gas-trap.
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 (LGM), some 20,000 years ago. Although the climate was cold, much of Siberia remained not glaciated for the simple reason that the climate was also extremely dry: the main area of glaciation [subject to glacial action] was in the Verkhoyansk Range in the east, which rises to nearly 2500 m. The low-lying plains of central Siberia saw the development of permafrost – defined as soil that remains at below freezing point [below -1°C or as low as -12°C] for two or more years. The prolonged cold of the last glacial period saw permafrost develop to great depths – over 1000 m 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 thawed and Siberian flora grows.
During the last glacial maximum, global sea levels fell by over a hundred metres with snow and ice deposit increase. The result is that the shallow seas of the ESAS became dry cold land, which allowed permafrost to develop. Climate warming in the Holocene geological epoch (approximately 12,000 years before present day) melted the big ice sheets in North 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 melt-pulse raised the temperature of the seawater-seabed interface dramatically so that it is considerably (>10 C) 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 land 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 and carbons 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.
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 m 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. In western Siberia, the Soviets extracted methane trapped beneath a large dome of permafrost; 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. U.S and other nations also have interest in mining methane hydrate.
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 rapid inward circulation of air masses about a low-pressure center, 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 ESAS 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 methane 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%, with local spikes over gas-productive areas. 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: domesticate animals emit about 80 million tonnes CH4 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 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 (GWP) 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.
[NOTE: Carbon has a global warming potential (GWP) of one. Methane GWP within a 20-year period rises to 72 GWP and over a period of 500 years, it falls to just 7.6 GWP. Compared to carbon, a tonne of methane emissions creates a strong burst of warming over a much shorter period. --DGE]
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, which indicates periods of temperature cycle-stability. 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. The second problem is finding a physical mechanism by which such an abrupt methane release of large magnitude could actually happen.
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 more global warming gas-temperature 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 to answers is for how long has this methane 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.
This piece is part one of a two-part series published at Skeptical Science.
Below is part two of the two-part Skeptical Science series.
Since 2000 CE, Dr. Natalia Shakhova has been working on joint projects with the Arctic Regional Center and Vitus Bering Laboratory. Dr. Shakhova has authored several papers regarding Russia’s East Siberian Arctic Shelf.
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 Siberian 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 (SkS), via email. Here are the responses, verbatim, to our questions.
SkS: You have stated 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. [NOTE: Self-preservation phenomenon of gas hydrates means that gas hydrates may exist in metastable state for prolonged time. Gas hydrates self-preservation phenomenon can be defined as a very slow decomposition of gas hydrates when the external pressure drops below a three-phase equilibrium pressure of the gas-ice-hydrate system at sub-zero (Celsius) temperature (below 270-271 K) as a result of thin ice film emergence on gas hydrate surface. This effect was initially discovered and described in detail over 1986-1992, by researchers from Canada (Ottawa National R&D Center) and Russia (by the joint team formed by VNIIGAZ and Moscow State University, identified as the ‘Moscow Gas Hydrate Group’). --DGE]
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 comprises 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 reconsider 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, pockmarks, 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 [Note: Holocene Epoch started approximately 12,000 years before present day, i.e., around 10,000 BC. Modern Global Warming Era of human carbon dioxide release started 1750 CE. --DGE]. 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 that was 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 seawater? 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 [the process of creating methane gas during metabolism]. 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 time frame?
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, the European Geosciences Union General Assembly 2008 stated that we consider release of up to 50 Gt 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?
[NOTE: Cenozoic Era is the most recent of the three Phanerozoic geological eras. Cenozoic Era covers from 65.5 million years ago to the present. Cenozoic Era includes K-T Mass Extinction at 65.5 Ma. The answer to SkS question about the methane record at 65.5 Ma is best answered by a specialist in paleoclimatology. --DGE]
NS: You would better address such a question to a specialist in paleoclimatology. 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.
SkS: 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 methane gas hydrates (PDF) for a briefing.
Summary
The research team have located new and large plumes of outgassing methane, in areas not previously investigated, so methane plumes is not necessarily a recent development when compared to other plumes within Cenozoic Era.
A large (multi-gigaton) abrupt methane 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 natural gas (methane) 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, pressure accumulation can build up to the point where the oil/gas is in highly pressurised state – hence the “blowouts” that have been recorded in some oilfields.
What Shakhova is suggesting is that buried gas hydrates accumulations of pressurised methane capped off by permafrost could be destabilized suddenly, with resulting release vast amounts of hydrate methane gas. I suggest a scenario where a strong increase in hydrate methane outgassing occurs not in one great quick “burp” at one locality, but there are multiple methane release pathways up through the defrosted sediment containing methane hydrate, over a wide area, over a geological brief period.
This post was originally published at Skeptical Science.
Fin
In 1750 CE, greenhouse interglacial concentrations levels for historic carbon dioxide peak levels were ~280 ppm and methane peak levels of ~700 ppb. The rapid rate of Modern of Global Warming carbon dioxide and methane greenhouse gases induced temperature increase is astonishing.
The first step to problem resolution is recognition of the problem. World leaders have yet to recognize global warming as a problem. There is certainty that unless there is a rapid political change in resolving global warming temperature increase, all human races terminate this century.
