Quantifying Arctic Methane

The paper 'Ebullition and storm-induced methane release from the East Siberian Arctic Shelf', was published in the journal Nature Geoscience on November 24, 2013.

The paper is dedicated “to the memory of the crew of Russian vessel RV Alexei Kulakovsky”, the 11 people who died when their tugboat perished in efforts to assist the scientists who were measuring methane from a fishing boat.

The research team used methods including drilling into the seabed of the Laptev Sea and sonar to analyse methane releases in the water, seeking to quantify the significant amounts of methane that are bubbling up from the sea bed in the East Siberian Arctic Shelf (ESAS, rectangle on image below), the area with shallow seas north of Siberia covering some 810,800 square miles (2.1 million square kilometers). By comparison, the United States (land and water) covers an area of nearly 10 million square kilometers.

“We have proven that the current state of subsea permafrost is incomparably closer to the thaw point than terrestrial permafrost, and that modern warming does contribute to warming the subsea permafrost,” says Natalia Shakhova, adding that an increase in storminess in the Arctic would further speed up the release of methane.

The scientists estimate, on the basis of the sonar data, that “bubbles escaping the partially thawed permafrost inject 100–630 mg methane square meters daily into the overlying water column”, and suggest that “bubbles and storms facilitate the flux of this methane to the overlying ocean and atmosphere, respectively”.

Some 17 teragrams (Tg or Mt) of methane escapes annually from the ESAS, said Natalia Shakova, lead study author and a biogeochemist at the University of Alaska, Fairbanks. This is an upgrade from the earlier estimate of 8 Tg of annual outgassing from the ESAS (Shakhova et al. 2010).

While including a reference to this earlier paper (Shakhova et al. 2010), the IPCC did give much lower estimates for emissions from all hydrates globally and from permafrost (excl. lakes and wetlands), i.e. 6 and 1 Tg per year, respectively.

And by comparison, IPCC estimates for all global methane emissions from manmade and natural sources go from 526 Tg per year to 852 Tg per year, of which 514 to 785 Tg per year is broken down (mostly by hydroxyl).

Sadly, as discussed in an earlier post, the IPCC has decided NOT to warn people about the danger that methane from hydrates will lead to abrupt climate change within decades. Yet, when entering the data by Shakhova et al. in a spreadsheet, a linear trendline (green line on image below) shows methane release in the ESAS reaching 20 Tg by 2013 and 26 Tg by 2015.

An exponential trendline (red/blue line) shows methane release in the ESAS reaching 22 Tg by 2013 and 36 Tg by 2015. Extending that same exponential trendline further into the future shows methane release in the ESAS reaching 2 Gt by the year 2031 and 50 Gt by the year 2043.

Note that accumulated totals over the years will be much higher than the annual release. While the IPCC gives methane a perturbation lifetime of 12.4 years, this methane will persist in the Arctic for much longer because its release is concentrated in the Arctic where hydroxyl levels are also very low.

Globally, IPCC/NOAA figures suggest that abundance of methane in the atmosphere currently (2013) is 1814 parts per billion (ppb), rising with 5 or 6 ppb annually, and that this rise is caused by a difference of 8 Tg between the methane emitted (548 Tg, top-down estimate) and broken down annually (540 Tg, top-down estimate). It is also worth noting that the IPCC has increased methane's global warming potential to 86 over 20 years with climate-carbon feedbacks, while there are reasons to assume that methane's impact, especially short-term and in case of large abrupt releases in the Arctic, is even stronger. Furthermore, the IPCC now gives methane a Radiative Forcing (RF) of 0.97 W/m^-2 (up from 48 W/m^-2 in 2007 and relative to 1750), as illustrated by the image below.

According to the IPCC, methane levels in 1750 and 2011 were 722 ppb and 1803 ppb, respectively. The total global methane burden is estimated to be about 5 Gt, i.e. 5 petagrams (Pg) or 5,000 Tg. A back-of-envelope calculation sugests that the methane burden in 1750 was 5 Gt x (722 : 1803) = 2 Gt. Furthermore, methane's 0.97 W/m^-2 RF is 42% of the total RF 2.29 W/m^-2. Therefore, the 3 Gt of methane that has been added to the atmosphere since 1750 is responsible for almost half of all the global warming since that time.

For now, the IPCC's estimated annual increase in global methane levels may seem small, but this figure appears to be based on low-altitude data collected over the past few decades. The total methane burden may already be rising much more rapidly, also because methane is rising in the atmosphere, increasing the burden especially at higher altitudes, as evidenced by the increasing occurence of noctilucent clouds. In other words, the 8 Tg estimate may reflect older data related to changes in lower-altitude measurements only, but the total methane burden may well be rising much more rapidly due to increases at higher altitudes. Further analysis comparing satellite data at different altitudes over the years could verify this.

An earlier post estimated that as much as 2.1 Mt (or 2.1 Tg) of methane could have been released abruptly end 2011. If you compare the animation of that earlier post with the recent animation, then current abrupt releases from the sea floor of the Arctic Ocean appear to be even higher.

As said, methane releases from the Arctic Ocean may for now seem small and may not yet make global temperatures rise much, but nonetheless the methane cloud hanging over the Arctic is contributing to warming locally. Combined with the increased likelyhood of extreme weather and rapid loss of ice and snow cover in the Arctic, this could make water temperatures in the Arctic Ocean rise even further, causing further destabilization of methane hydrates. Furthermore, the mechanical force of methane release from hydrates (rapidly expanding 160 times in volume) itself can also contribute to hydrate destabilization. Seismic activity could also lead to destabilization. Indeed, there are many factors that could contribute to exponential rise of methane release from the Arctic Ocean, as discussed in the post on methane hydrates, which calls for comprehensive and effective action, such as discussed at the Climate Plan blog.


References

Ebullition and storm-induced methane release from the East Siberian Arctic Shelf, by Natalia Shakhova, Igor Semiletov, Ira Leifer, Valentin Sergienko, Anatoly Salyuk, Denis Kosmach, Denis Chernykh, Chris Stubbs, Dmitry Nicolsky, Vladimir Tumskoy & Örjan Gustafsson (2013)
http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2007.html

Arctic storms speed up release of methane plumes, by Fred Pearce
http://www.newscientist.com/article/dn24639-arctic-storms-speed-up-release-of-methane-plumes.html

Twice as Much Methane Escaping Arctic Seafloor, by Becky Oskin
http://www.livescience.com/41476-more-arctic-seafloor-methane-found.html

Extensive methane venting to the atmosphere from sediments of the East Siberian Arctic shelf, by Natalia Shakhova, Igor Semiletov, Anatoly Salyuk, Vladimir Yusupov, Denis Kosmach, and Örjan Gustafsson, in: Science, 327, 1246-1250 (2010).
http://www.sciencemag.org/content/327/5970/1246.abstract

On carbon transport and fate in the East Siberian Arctic land–shelf–atmosphere system, by Semiletov et al. (2012)
http://iopscience.iop.org/1748-9326/7/1/015201

Intergovernmental Panel on Climate Change (IPCC), AR5 Working Group 1
http://www.climatechange2013.org/

Post by Sam Carana.

Just do NOT tell them the monster exists

The Arctic Methane Monster

As discussed in a previous post, the IPCC appears to be acting as if there was a carbon budget to divide among countries, whereas in reality there is a huge carbon debt to our children, while the situation could become catastrophic any time soon.

Indeed, carbon dioxide is not the only greenhouse gas and the Arctic methane monster is threatening to disrupt the cosy lifetyle of those who want to keep selling parts of such non-existing carbon budgets.

So, who do you think the IPCC has been listening to, to reach a conclusion after six years of analysis? Experts or snake oil sellers? The cartoon may give you a hint, but why don't you make up your own mind by going over the IPCC statements and comments below.

Abrupt Climate Change

The IPCC recently issued AR5 documents that included a discussion of Abrupt Climate Change.

from: IPCC AR5 Working Group 1 Technical Summary (final draft)

The IPCC gives some examples:

Yes, methane release from clathrates sounds scary.

If there is little consensus on the likelihood, then surely some experts do believe it is likely. Yet, the IPCC somehow reaches the following conclusion, and does so with high confidence:

Unlikely? What was the basis for this IPCC conclusion? 

This seems like a conclusion that can only have been reached after a robust analysis of all the evidence. So, how did the IPCC reach this conclusion, given that it did so with such high confidence?

Let's have a look. The above conclusion is preceeded by this statement:

OK, that means clathrates will increasingly become destabilized. The IPCC then adds an argument why this would not result in abrupt climate change this century.

Sure, but that's just one rather insignificant negative feedback, compared to the many more significant positive feedbacks, such as melting causing isostatic rebound that can contribute to the occurrence of earthquakes and landslides, in turn triggering methane release. Yet, without even mentioning these positive feedbacks, the paragraph then jumps to the following conclusion:

If these initial estimates are not insignificant and if it's all rather difficult to formally assess, how then is it possible that the IPCC reached its end-conclusion with such high confidence? Moreover, was there any basis for these "initial estimates"? Perhaps there's more elsewhere in the IPCC documents. Here's another paragraph that preceeded the above.

All this expresses is low confidence in existing modeling and lack of understanding of the various processes. Again, how then is it possible that the IPCC reached its conclusion with such high confidence?

How much methane is currently released from hydrates?

On this, the IPCC says:

OK, so things could become scary. And sure, there are no large abrupt releases taking place now, but that doesn't mean there's not going to be any in future. In case of gradual processes, it makes sense to base projections on historic releases. In case of abrupt releases, however, current releases should not be the basis for reaching a conclusion with high confidence.

So, was the work of Dr. Natalia Shakhova perhaps used as the basis for these estimates? Read on!

How much methane is stored under the Arctic Ocean?

How much methane is present in sediments under the seabed of the Arctic Ocean, in the form of free gas and hydrates? On this, the IPCC says in FAQ6:

That doesn't seem to reflect the estimates of Dr. Natalia Shakhova. According to older estimates, the total amount of methane in the atmosphere is about 5 Gt. Saying that more than 50 Gt of methane could be stored in hydrates the Arctic seems deceptive and appears to be seriously downplaying a very dangerous situation.

Natalia Shakhova et al. in 2010 estimated the accumulated potential for the East Siberian Arctic Shelf (ESAS) region alone (image on the right) as follows:

• organic carbon in permafrost of about 500 Gt
• about 1000 Gt in hydrate deposits
• about 700 Gt in free gas beneath the gas hydrate stability zone.

Back in 2008, Natalia Shakhova et al. considered release of up to 50 Gt of predicted amount of hydrate storage as highly possible for abrupt release at any time. Did the IPCC perhaps misread the figures, mistaking the part of the methane that is ready for abrupt release for the total amount of methane in the Arctic?

How long could it take for large amounts of methane to reach the atmosphere?

How long could it take for large amounts to reach the atmosphere? On this, the IPCC says in FAQ6, in the same and the next paragraph:

Events in which most, if not virtually all methane that escaped from the seabed did enter the atmosphere have been studied in 2002 and published in 2006, as reported at:
http://www.ia.ucsb.edu/pa/display.aspx?pkey=1482
and at:
http://onlinelibrary.wiley.com/doi/10.1029/2005GB002668/abstract

Below, a screenshot from an interview of John Mason with Natalia Shakhova, published at:
http://www.skepticalscience.com/arctic-methane-outgassing-e-siberian-shelf-part2.html

In conclusion, Dr Natalia Shakhova also rejects the idea that methane release from hydrates always takes place gradually, over a long time. Especially in the Arctic, there's a huge danger of abrupt release, given the accelerated warming that takes place in the Arctic, given the huge amounts of methane stored in sediments in the form of free gas and methane, given the presence of a tectonic fault line, etc, etc.

Once released, methane won't get broken down easily in the Arctic Ocean, as this requires the presence of bacteria that can oxidize the methane, as well as free oxygen in the water. Once depleted, oxygen isn't quickly replenished in the Arctic Ocean. Lack of bacteria and depletion of oxygen in the waters of the Arctic Ocean could prevent oxidation of methane rising up in the waters, as described at:
http://methane-hydrates.blogspot.com/2012/03/large-areas-of-open-ocean-starved-of.html

In the Arctic, low temperatures mean there are less bacteria that need more time to break down the methane. In other places, currents may bring bacteria back to the location of the methane plume repeatedly. In the Arctic, many currents are long, so once bacteria have flowed away from the location of the plume, they could be driven out of the Arctic Ocean or may return only after a long time, i.e. too long to survive in Arctic waters which are cold and often ice-covered, so a lot of time little or no sunshine penetrates the waters.

In the Arctic, the danger is much larger that methane releases will overwhelm the capacity of bacteria to break it down in the water. In case of large abrupt releases in the Arctic, the danger is that much of the methane will reach the atmosphere unaffected and remain there for a long time, due to the Jet Stream and the low levels of hydroxyl in the Arctic atmosphere, as further described at:
http://methane-hydrates.blogspot.com/2013/04/methane-hydrates.html

BTW, how did all this methane manage to reach the atmosphere over the Arctic Ocean? 

Methane levels over the Arcic Ocean appear to be rising, as illustrated by the combination of images below, showing methane levels over five years (2009 on the left, to 2013 on the right), each time for the same period (January 21-31) - images by Dr. Leonid Yurganov.

[ Click on image to enlarge - from: Dramatic increase in methane in the Arctic in January 2013 ]

If the IPCC was right, how then was it possible methane levels to rise so sharply and abruptly. How was it possible for large amounts of methane to be present over the deep waters of the Arctic Ocean, as discussed at:
http://arctic-news.blogspot.com/2013/10/methane-over-deep-waters-of-arctic-ocean.html

[ How did this methane get there? - click on image to enlarge - see also: Methane over deep waters of Arctic Ocean ]

There is a wealth of evidence from scientists such as Igor Semiletov and Natalia Shakhova who have - year after year - been taking measurements in the East Siberian Arctic Shelf, complete with first-hand reports that methane plumes have been detected.

"We've found continuous, powerful and impressive seeping structures more than 1,000 metres in diameter. In a very small area, less than 10,000 square miles, we have counted more than 100 fountains, or torch-like structures, bubbling through the water column and injected directly into the atmosphere from the seabed," Dr Semiletov said, "We carried out checks at about 115 stationary points and discovered methane fields of a fantastic scale - I think on a scale not seen before. Some of the plumes were a kilometre or more wide and the emissions went directly into the atmosphere - the concentration was a hundred times higher than normal."  -  Vast methane 'plumes' seen in Arctic ocean as sea ice retreats, by Steve Connor in The Independent, December 13, 2011.

The image below shows a cluster of methane plumes, over one km in diameter, that appeared in the Laptev Sea end September 2011. The image is part of a paper on the unfolding "Methane Catastrophe".

Of course, we all wished that we're wrong about this terrifying Arctic methane threat, but the precautionary principle demands a thorough investigation of observations that appear to be at odds with wishful thinking, especially when the stakes are so high. So, IPCC, where's the evidence?

Related

- Arctic Methane Monster
http://arctic-news.blogspot.com/2013/09/arctic-methane-monster.html

- Methane over deep waters of Arctic Ocean
http://arctic-news.blogspot.com/2013/10/methane-over-deep-waters-of-arctic-ocean.html

- Methane hydrate myths
http://methane-hydrates.blogspot.com/p/myths.html

- Methane hydrates
http://methane-hydrates.blogspot.com/2013/04/methane-hydrates.html

- Methane release caused by earthquakes
http://arctic-news.blogspot.com/2013/09/methane-release-caused-by-earthquakes.html

- Earthquake hits Laptev Sea
http://arctic-news.blogspot.com/2013/09/earthquake-hits-laptev-sea.html

- North Hole
http://arctic-news.blogspot.com/2013/09/north-hole.html

- Seismic activity, by Malcolm Light and Sam Carana (2011)
Arctic-news.blogspot.com/p/seismic-activity.html

- Thermal expansion of the Earth's crust necessitates geoengineering (2011)
Arctic-news.blogspot.com/p/thermal-expansion.html

Arctic methane: Why the sea ice matters

Arctic methane: Why the sea ice matters 

a new film by Envisionation.co.uk

Interviews with:

James Hansen - NASA

Natalia Shakhova - IARC

Peter Wadhams - Cambridge University, UK

David Wasdell - Apollo-Gaia Project

Arctic Methane: Why The Sea Ice Matters

Link: https://www.youtube.com/watch?v=iSsPHytEnJM

Short link: https://youtu.be/iSsPHytEnJM

James Hansen: If it begins to allow the Arctic Ocean to warm up and warm the ocean floor, then we'll begin to release methane [from] hydrates, and if we let that happen, that's a potential tipping points that we don't want to pass. There are now observations that methane is beginning to be released by both melting tundra on the land and bubbling up in the Arctic Ocean, indicating some warming of the Arctic Ocean.

Natalia Shakhova: The total amount of methane in the current atmosphere is about 5 Gt. The amount of carbon preserved in the form of methane in the East Siberian Arctic Shelf is ~ from hundreds to thousands Gt. What divides this methane from the atmosphere is a very shallow water column and a weakening permafrost, which is losing its ability to serve as a seal. This area is very seismically and tectonically active and there was some investigation that the tectonic activity is increasing.

Peter Wadhams: At the rate we're going, it will bring us to an ice-free Arctic in about four years time. [The Arctic Ocean] now warms up to about 5 degrees [5°C or 41°F, i.e.] enough to start warming up the seabed. The seabed at the moment is frozen, but it's now starting to melt. That's allowing a lot of methane which is trapped under the permafrost to be released. That's a large boost to global warming, because methane is an extremely powerful climatically-active gas. 

David Wasdell: The warm water from the surface is now being mixed down to those areas that it never reached when the whole area was covered in sea ice. As soon as the area is open water, you have a process of heating that goes right down to those clathrate deposits on the seabed. The more the methane is released into the atmosphere, the faster the heating goes. It's probably the greatest threat we face, as a planet. We're already in a mass extinction event.

Further quotes
Further videos
News reports
FAQs
Facts

Highlights of EGU General Assembly 2012

If you will be attending the European Geosciences Union (EGU) General Assembly on April 25, 2012, make sure to attend, from 14:00 to 14:15 in room 23, the presentation:

Methane release from the East-Siberian Arctic Shelf and its connection with permafrost and hydrate destabilization: First results and potential future developments
by Natalia Shakhova and Igor Semiletov

The East Siberian Arctic Shelf (ESAS) is home to the world’s largest hydrocarbon stocks, which consist of natural gas, coal bed methane (CH4), and shallow Arctic hydrates. Until recently, the ESAS was not considered a CH4 source due to the supposed impermeability of sub-sea permafrost, which was thought to completely isolate the CH4 beneath from modern biogeochemical cycles.

However, the ESAS represents an enormous potential CH4 source that could be responsive to ongoing global warming. Such response could occur in substantially shorter time than that of terrestrial Arctic ecosystems, because sub-sea permafrost has experienced long-lasting destabilization initiated by its inundation during the Holocene ocean transgression. ESAS permafrost stability and integrity is key to whether sequestered ancient carbon escapes as the potent greenhouse gas CH4.

Recent data suggest the sub-sea permafrost is currently experiencing significant changes in its thermal regime. For example, our recent data obtained in the ESAS during the drilling expedition of 2011 showed no frozen sediments at all within the 53 m long drilling core at water temperatures varying from -0.6˚C to -1.3˚C.

Unfrozen sediments provide multiple potential CH4 migration pathways. We suggest that open taliks have formed beneath the areas underlain or influenced by the nearby occurrence of fault zones, under paleo-valleys, and beneath thaw lakes submerged several thousand years ago during the ocean transgression. Temporary gas migration pathways might occur subsequent to seismic and tectonic activity in an area, due to sediment settlement and subsidence; hydrates could destabilize due to development of thermokarst-related features or ice-scouring.

Recently obtained geophysical data identified numerous gas seeps, mostly above prominent reflectors, and the ubiquitous occurrence of shallow gas-charged sediments containing numerous gas chimneys, underscoring the likelihood that the ability of sub-sea permafrost to capture CH4 released from the seabed is failing.

Available data suggest the ESAS sub-sea permafrost is currently leaking a substantial amount of CH4. We propose that a few different types of CH4 exist, and are becoming involved in the modern carbon cycle due to permafrost destabilization in the ESAS: modern biogenic CH4 produced from ancient substrate, relatively old biogenic CH4 mobilized from hydrate deposits, and old thermogenic CH4 accumulated within seabed deposits. Isotopic data obtained by sampling CH4 in the water column and atmospheric CH4 in close proximity to the sea surface confirm the contribution from different sources, and demonstrate that the isotopic signature of CH4 from the ESAS can be used to create an interpretive plot for defining hydrates. CH4 fluxes could occur as numerous weak seeps, as large areas of strong bubble plumes, or as sites where CH4 releases are flare- or torch-like and the emissions are non-gradual.

Due to the shallow and oligotrophic nature of the ESAS, the majority of aqueous CH4 may avoid biological oxidation in the water column and escape to the atmosphere.

Further investigations should be focused on quantifying the total CH4 pool of the ESAS, improving our understanding of the mechanisms responsible for sub-sea permafrost destabilization and gas migration pathways formation, and decreasing uncertainties regarding the current CH4 emission mode and its future alteration by progressing permafrost degradation.

Geophysical Research Abstracts
Vol. 14, EGU2012-3877-1, 2012
EGU General Assembly 2012

Above presentation is part of the session:
Methane cycling in marine and terrestrial systems

which also features, as part of the poster program:
Display Time: Wednesday, 25 Apr 08:00–19:30
Attendance Time: Wednesday, 25 Apr 17:30–19:00
Poster Area BG

First drilling subsea permafrost in the southeastern Laptev Sea, the East Siberian Arctic Shelf: results and challenges
by Igor Semiletov, et al.
highlighting the following two challenges:

1) observed Arctic warming in early 21st century is stronger than predicted by several degrees, which may accelerate thaw release of methane from the upper seafloor layer by increasing bottom erosion and from deeper stratums (including hydrates) by sediment settlement and adjustment;

2) drastic sea ice shrinkage causes increase in storm activities and deepening of the wind-wave-mixing layer down to depth ~50 m that enhance methane release from the water column to the atmosphere.

Geophysical Research Abstracts
Vol. 14, EGU2012-3913, 2012
EGU General Assembly 2012