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Tigertown

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Re: Arctic Methane Release
« Reply #750 on: November 30, 2018, 05:23:10 PM »
Many of the 300 or so Arctic lakes studied by Katey Walter Anthony, have been noted by her to be so shallow that the methane reaches the surface before the microbes that would normally break it down has time to do very much. She often sets it on fire to demonstrate this, both on frozen and non frozen lakes.
Also, it might be worth noting that a large portion of the ESAS is less than 50m deep. Not sure how immediate of a concern that is but, it is a ticking time bomb indeed.

gerontocrat

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Re: Arctic Methane Release
« Reply #751 on: November 30, 2018, 06:08:01 PM »
A vague memory (maybe from those Russians again?).

When CH4 release from the sea floor into the sea is slow, it does so in small bubbles. This means that even in shallow seas it can be mostly oxidised before reaching the surface and released into the atmosphere.

When CH4 from the sea floor is released into the sea under pressure it does so in bigger bubbles. This reduces the fraction oxidised by the time it reaches the surface and released into the atmosphere.

This simply due to that oxidation works on the surface of the bubble- a bubble with double the diameter contains 8 times the volume and only 4 times the surface area. (3 x diam, 27xvol & 9xsurface & so on).

This would suggest studies that looked at methane release to the atmospehere at places with gradual slow seepage would produce different results from those at places where CH4 burps.

BUT one has to wait for the atmospheric CH$ ppb data - how many years before any effect can be distinguished ?

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Re: Arctic Methane Release
« Reply #752 on: November 30, 2018, 06:55:06 PM »
Then Cowtan & Way were published. And they were heavily criticized by the consensus group incl. on Real Climate who basically claimed they were wrong and they had serious errors in their "work". [...]

Now C&W are seen as "heroes" on RC where before they were seen as "minority cranks" and plainly wrong!

I don't believe that's a remotely realistic description of what happened.  Here's the first post on RealClimate, back in 2013, announcing the exciting new paper by Cowtan and Way:

http://www.realclimate.org/index.php/archives/2013/11/global-warming-since-1997-underestimated-by-half/

It's entirely complimentary.  There's no criticism at all of C&W.  Subsequent coverage on RC and elsewhere in the mainstream climate science community was similarly supportive. 

SteveMDFP

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Re: Arctic Methane Release
« Reply #753 on: November 30, 2018, 07:44:24 PM »


When CH4 from the sea floor is released into the sea under pressure it does so in bigger bubbles. This reduces the fraction oxidised by the time it reaches the surface and released into the atmosphere.

I believe your post is entirely accurate, as far as it goes.  What  is missing is consideration of solubility of methane in sea water by depth.  At the surface, at atmospheric pressure, methane is practically insoluble.  At great depth/pressure, however, methane is quite soluble.  So those large bubbles from the deep don't just have to be oxidized to disappear, they mostly dissolve at depth.  Even quite prodigious deep seeps generally don't result in observable bubbling at the surface.

A separate consideration, however, is that every mole of methane, when it is dissolved or oxidized, consumes a mole of dissolved oxygen.  The amount of oxygen at depth isn't determined by oxygen solubility at depth, but oxygen solubility at the surface, where it is produced by plankton.

The impact of methane release on ocean anoxia (a steadily increasing problem) is a matter I've not seen examined in these discussions.

gerontocrat

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Re: Arctic Methane Release
« Reply #754 on: November 30, 2018, 08:53:35 PM »


When CH4 from the sea floor is released into the sea under pressure it does so in bigger bubbles. This reduces the fraction oxidised by the time it reaches the surface and released into the atmosphere.

I believe your post is entirely accurate, as far as it goes.  What  is missing is consideration of solubility of methane in sea water by depth.  At the surface, at atmospheric pressure, methane is practically insoluble.  At great depth/pressure, however, methane is quite soluble.  So those large bubbles from the deep don't just have to be oxidized to disappear, they mostly dissolve at depth.  Even quite prodigious deep seeps generally don't result in observable bubbling at the surface.

A separate consideration, however, is that every mole of methane, when it is dissolved or oxidized, consumes a mole of dissolved oxygen.  The amount of oxygen at depth isn't determined by oxygen solubility at depth, but oxygen solubility at the surface, where it is produced by plankton.

The impact of methane release on ocean anoxia (a steadily increasing problem) is a matter I've not seen examined in these discussions.
I was thinking much more of methane release from under shallow seas such as the ESAS and relatively shallow lakes. I have no view on deep-sea deposits, anoxia etc as my poor brain is already full-up of reasons why it will be tears before bedtime for most life on this planet.
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Ken Feldman

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Re: Arctic Methane Release
« Reply #755 on: November 30, 2018, 10:55:35 PM »
I think there are two separate claims running in this thread - that methane can't meaningfully reach the surface, as proved by many scientific papers; and that the scale of the methane seepage does not have a drastic effect on the global scale.
Based on Dr. Semiletov's evidence, the first claim is false. The second is true for now.

Oren,

You can't say the first claim is false.  There have been many field expeditions to the Arctic to test whether the atmosphere above the methane seeps is higher in methane concentration than background and they've' found that there are slightly elevated readings near the seeps, but the methane concentration quickly fades to the background levels within a few 100 meters of where the methane breaks the water surface.

Here's one from 2016, reporting on measurements taken in the Laptev and Eastern Siberian Seas (over the ESAS) in 2014:

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016GL068977

Quote
The methodological approach in this paper (high‐resolution simultaneous continuous measurements in surface waters and in the air) allows us to test two recently proposed hypotheses about sea‐air exchange of CH4 across the ESAS. The proposed extensive bubble flux from subsea CH4 seeps to the atmosphere could not be validated for the middle and outer ESAS waters >35 m depth. Neither widespread strong enhancements of ambient CH4 nor strong near‐surface gradients could be identified. Our high‐resolution data set rather suggests a spatially limited effect of gas seep bubbles on atmospheric CH4 mixing ratios. Instead, diffusive fluxes alone can explain observed atmospheric mixing ratios that are slightly elevated in some areas but much less than those reported for shallow inshore areas.

Note that this is consistent with the results from the paper I posted upthread that studied the Beaufort Sea.  They found no elevated methane levels in the atmosphere where the ocean depth was greater than 30 m.

Quote
Our annual flux, not accounting for impermeable ice cover periods, is in rough agreement with previously reported regional fluxes based on measurements in open waters of the LS and ESS, 1–4.5 Tg yr−1 [Shakhova et al., 2005], though later work noted similar fluxes with additional contribution from subsea CH4 seeps [Salyuk and Semiletov, 2010]. A more recent study focused on shallower portions of the LS and ESS (6–24 m depth) and found an average flux of 287 mg m−2 d−1, based on bubble fluxes derived from sonar [Shakhova et al., 2014]. This same study also extrapolated shelf‐wide fluxes as well, reporting a flux from subsea CH4 seeps to the atmosphere of 9 Tg CH4 yr−1, and a total flux (including diffusive fluxes) of 17 Tg CH4 yr−1 for the LS and ESS, by estimating that their study accounted for 10% of extant ESAS seeps. Finally, we note that our in situ results (along with all previous in situ results) are higher than a recent model of CH4 release (bubbling + diffusion) from the Siberian continental shelves of 0.42 Tg yr−1 [Archer, 2015] but are similar to a recent modeling estimate based on Pan‐Arctic CH4 measurements from long‐term monitoring stations on land [Berchet et al., 2016].
j

Note the comparisons to modeled results and results posted by S&S.

Quote
As noted above, our seawater CH4 measurements do not exclude bubbles, and over several days of continuous measurements crossing the seep regions, our seawater CH4 values certainly incorporate some bubble‐delivered CH4 in the surface waters. There is a large difference in transport success of bubble‐contained CH4 in 6 m deep water and 40 m deep water [McGinnis et al., 2006]; rapid exchange and loss of CH4 to the generally deeper water column in our study alone may account for some of this difference between our and previous studies closer to shore [Sergienko et al., 2012; Shakhova et al., 2014], in shallower depths than studied during SWERUS‐C3 (>35 m). Assuming an average CH4 concentration for the entire water column, we calculated the necessary sustained fluxes to raise the atmospheric concentrations by various amounts. We assumed a very shallow 200 m mixing height (very low inversions were observed during SWERUS‐C3) [Tjernström et al., 2015], a 35 m water column, and an 80 ppb atmospheric CH4 enhancement, raising atmospheric CH4 from apparent background levels of about 1.87 ppm to 1.95 ppm. This requires a sustained CH4 flux of about ~12 mg m−2 d−1, similar to the fluxes we observed during SWERUS in areas near subsea gas seeps on the ESAS (Table 2). An average flux near ESAS subsea seeps of 13 mg m−2 d−1 was reported previously [Sergienko et al., 2012]. Sustaining higher atmospheric CH4 concentrations is even more difficult: to sustain 2.1 ppm CH4 in the atmosphere (35 m water column, 200 m mixing height) would require a flux similar to a subarctic wetland (~36 mg m−2 d−1) Bartlett and Harriss, 1993] or an order of magnitude above the average fluxes we observed in the ice‐free ESAS.  [(Various mixing scenarios' effects on atmospheric CH4 are shown in the supporting information Table S2.)

Again, note the comparisons with S&S results and comparisons with the emissions from subarctic wetlands (which I bolded above). 

The study goes on to address shallower parts of the ESAS (but note that more than half of the ESAS, with an average depth of 50 meters, is deeper than the 30 to 35 meter depths where methance doesn't reach the surface):

Quote
Surveys conducted in shallower waters, closer inshore, have reported substantially higher atmospheric CH4, 2.97 and 2.66 ppm average in the LS and ESS, respectively, with spikes to 8.2 ppm [Semiletov et al., 2012; Shakhova et al., 2010a, 2010b, 2007]. Such average atmospheric mixing ratios of CH4 across large expanses of the LS and ESS require sustained regional CH4 fluxes of roughly 75–200 mg m−2 d−1, depending on local winds and atmospheric mixing. Such atmospheric enhancements are not sustainable by local diffusive CH4 fluxes alone but require a substantial bubble contribution, due to mixing limitations and the strong salinity gradient which acts as formidable barrier to mixing and transport in the ESAS, especially in the LS [Wåhlström et al., 2012]. Using an entrainment velocity model (supporting information), we note that even with sustained gale force winds of 20 m s−1, entrainment velocities in the LS are only 10 cm h−1, suggesting that a week is needed to mix from 15 m depth. Storms with winds >15 m s−1 occur on average only once or twice each summer in the ESAS [Proshutinsky et al., 1999], even less close to shore [Günther et al., 2015], though rare large storms have occurred [Simmonds and Rudeva, 2012]. Thus, during the ice‐free sea season, generally, only the upper 10 m of water is subject to surface layer turbulent mixing. This stratification likely contributes to limiting the diffusive transport of CH4 from deeper waters to the surface.

Here's what the researchers concluded (emphasis added):

Quote
Our measurements of CH4 in the atmosphere and surface water across the middle and outer ESAS during July and August 2014 show an average flux of CH4 from the Siberian shelf seas to the atmosphere (along the ice‐free portions of the cruise track) of 3.8 mg m−2 d−1. In a region of CH4 seeps in the LS, fluxes reached 14 mg m−2 d−1. Enhanced levels of CH4 were observed in below‐ice waters of the ESS; such CH4 would have to be stored for winter months and released with near‐100% efficiency after late summer or early autumn ice‐out, providing a short‐duration increase to the total flux, to reach annual fluxes of 2.9 Tg yr−1. Such short‐duration fluxes at ice‐out must be better quantified to constrain the total annual flux. We note that the below‐ice CH4 concentrations in the ESS were considerably below what would be expected if CH4 was collected over the entire ice‐covered months, suggesting overwinter loss processes and/or incorporation into sea ice. This, combined with a lack of knowledge of fluxes through the full ice‐free season, causes us to regard our annual estimates of ESAS sea‐air CH4 fluxes (2.9 Tg yr−1) as very likely high rather than low. Unquantified ice‐out fluxes could increase the annual ESAS CH4 flux above the estimated ice‐free season flux of 0.87 Tg yr−1. Although our estimated sea‐air CH4 fluxes for the ESAS far exceed fluxes reported for other shelf seas, they are roughly an order of magnitude below ESAS CH4 flux estimates reported previously. Reconciling these differences requires much better knowledge of the spatial extent of ESAS CH4 sources (including near‐shore areas not accessible during SWERUS‐C3 where riverine and terrestrial CH4 sources may play a greater role), especially the seemingly highly localized bubble sources, as well as quantification of stored CH4 released at ice‐out.

This study concluded that the then current (2014) estimate of methane release from the ESAS into the atmosphere of 2.9 Tg per year is too high. 

Also, multiple studies have shown that methane released from depths of greater than 30m don't reach the surface (I think even S&S reached this conclusion, I forget whether it was in their 2010 or 2013 paper).






magnamentis

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Re: Arctic Methane Release
« Reply #756 on: November 30, 2018, 11:29:25 PM »

This study concluded that the then current (2014) estimate of methane release from the ESAS into the atmosphere of 2.9 Tg per year is too high. 

Also, multiple studies have shown that methane released from depths of greater than 30m don't reach the surface (I think even S&S reached this conclusion, I forget whether it was in their 2010 or 2013 paper).

thank you for this great resume  8)
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Wherestheice

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Re: Arctic Methane Release
« Reply #757 on: November 30, 2018, 11:43:00 PM »
Some here are very convinced the methane threat isn’t real. I’m out
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oren

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Re: Arctic Methane Release
« Reply #758 on: November 30, 2018, 11:57:00 PM »
Ken thank you for the summaries. I note the distinction between relatively deep water, >30 or >35 meters, and very shallow water where methane can and does reach the surface.

Gray-Wolf

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Re: Arctic Methane Release
« Reply #759 on: December 01, 2018, 12:12:43 AM »
Some here are very convinced the methane threat isn’t real. I’m out

I believe upthread someone said something along the lines of 'What could change ( in the science) in 2 years?' Yet in 2014 we got the first reports/images of a yamal 'blowout' and 2 years later we have reports of over 1,000 newly heaved up 'pingo like structures' then the 'on the ground' ,eyes on the prize, info would suggest that a lot can change in 2 years?

I never got my question answered either so I guess the guys who were busy telling us it could never happen ,even as the 'Pingo like structures' were heaving out of the permafrost, have no opinion on the events of the real world just what their models are telling them?

I believe the info since the 'Boiling Oceans' reports from the ESS in 2010 point to the start of a release episode and , should Semiletov's timings be correct for the length of time it takes from formation to blowout crater, Yamal goes POP this coming summer?

EDIT: I suppose the Anchorage quake is a timely reminder that 'natural' events will also continue on and degraded permafrost caps for clathrate deposits on continental shelf areas could find themselves destabilised at any time?
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magnamentis

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Re: Arctic Methane Release
« Reply #760 on: December 01, 2018, 12:58:49 AM »
is it possible that the differences stem from whether we are talking of mass release (explosive events) or slow steady releases.

i cannot believe that anyone would not take methane release tread for real. as far as i know it happened in the past and scientists were able to reproduce parts of the events. if i remember correctly that was off the norwegian coast.

unfortunately i know too little about it and what i do know is from reading about it over many years in small portions. only thing i got convinced in the process of gathering information over many years is that sooner or later we are going to see catastrophic mass release of entire "frozen" methane that is held stable only under high pressure and below certain temps in deep seas, while there is much talk about < 30m of depth and apparently this is not the same "threat" like the methane hydrate (a clathrate compound)

do you guys recommend to read upthread to get a better picture or elsewhere ?
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Ken Feldman

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Re: Arctic Methane Release
« Reply #761 on: December 01, 2018, 01:20:38 AM »
Some here are very convinced the methane threat isn’t real. I’m out

I believe upthread someone said something along the lines of 'What could change ( in the science) in 2 years?' Yet in 2014 we got the first reports/images of a yamal 'blowout' and 2 years later we have reports of over 1,000 newly heaved up 'pingo like structures' then the 'on the ground' ,eyes on the prize, info would suggest that a lot can change in 2 years?

I never got my question answered either so I guess the guys who were busy telling us it could never happen ,even as the 'Pingo like structures' were heaving out of the permafrost, have no opinion on the events of the real world just what their models are telling them?

I believe the info since the 'Boiling Oceans' reports from the ESS in 2010 point to the start of a release episode and , should Semiletov's timings be correct for the length of time it takes from formation to blowout crater, Yamal goes POP this coming summer?

EDIT: I suppose the Anchorage quake is a timely reminder that 'natural' events will also continue on and degraded permafrost caps for clathrate deposits on continental shelf areas could find themselves destabilised at any time?

Gray-Wolf,

I did respond, and you even paraphrased my comment about not much changing in two years (between Real Climate's response about methane craters discovered in 2014 and the new Yamal craters appearing in 2016). 

Submarine methane craters have been known about for decades.  Here's a paper from 1992 discussing them:

https://forum.arctic-sea-ice.net/index.php?action=post;quote=182696;topic=12.750

What's new is that scientists have found craters in the permafrost on land (starting in 2014) and that a methane explosion that was near enough to humans was witnessed in 2016 or 2017.  However, the existence of vast amounts of methane in permafrost has been know about for decades and the possibility of it warming enough to release that methane has been acknowledge.  One of the reasons for the goal of keeping global warming to less than 2 degrees C as agreed upon in international treaties is to avoid some of the impacts, like massive releases of methane from the permafrost.

I think the important part of to think about these craters is how much methane they can release into the atmosphere and how much that would increase the global warming.  The short answer is it would take about 20 million of these explosions occurring within about a decade (after which time the methane is converted to CO2 and other gases) to release enough methane to raise the global temperature by about 2 degrees C.  If the methane continues to leak out a current rates, or even at 10 times current rates, it wont really impact warming much.   Based on field observations, methane emissions from the ESAS are less than 2.9 Tg per year.  Global methane emissions are around 550 Tg per year.  So even if the arctic emissions were to increase by ten-fold, they'll still be pretty low compared to other GHG emissions.

Not many scientists believe that is very likely with the warming in the oceans and land that we've seen to date.  These include scientists who have gone to the Arctic and measure the methane coming out of the methane seeps.

Wherestheice

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Re: Arctic Methane Release
« Reply #762 on: December 01, 2018, 03:06:43 AM »
Some here are very convinced the methane threat isn’t real. I’m out

I believe upthread someone said something along the lines of 'What could change ( in the science) in 2 years?' Yet in 2014 we got the first reports/images of a yamal 'blowout' and 2 years later we have reports of over 1,000 newly heaved up 'pingo like structures' then the 'on the ground' ,eyes on the prize, info would suggest that a lot can change in 2 years?

I never got my question answered either so I guess the guys who were busy telling us it could never happen ,even as the 'Pingo like structures' were heaving out of the permafrost, have no opinion on the events of the real world just what their models are telling them?

I believe the info since the 'Boiling Oceans' reports from the ESS in 2010 point to the start of a release episode and , should Semiletov's timings be correct for the length of time it takes from formation to blowout crater, Yamal goes POP this coming summer?

EDIT: I suppose the Anchorage quake is a timely reminder that 'natural' events will also continue on and degraded permafrost caps for clathrate deposits on continental shelf areas could find themselves destabilised at any time?

Gray-Wolf,

I did respond, and you even paraphrased my comment about not much changing in two years (between Real Climate's response about methane craters discovered in 2014 and the new Yamal craters appearing in 2016). 

Submarine methane craters have been known about for decades.  Here's a paper from 1992 discussing them:

https://forum.arctic-sea-ice.net/index.php?action=post;quote=182696;topic=12.750

What's new is that scientists have found craters in the permafrost on land (starting in 2014) and that a methane explosion that was near enough to humans was witnessed in 2016 or 2017.  However, the existence of vast amounts of methane in permafrost has been know about for decades and the possibility of it warming enough to release that methane has been acknowledge.  One of the reasons for the goal of keeping global warming to less than 2 degrees C as agreed upon in international treaties is to avoid some of the impacts, like massive releases of methane from the permafrost.

I think the important part of to think about these craters is how much methane they can release into the atmosphere and how much that would increase the global warming.  The short answer is it would take about 20 million of these explosions occurring within about a decade (after which time the methane is converted to CO2 and other gases) to release enough methane to raise the global temperature by about 2 degrees C.  If the methane continues to leak out a current rates, or even at 10 times current rates, it wont really impact warming much.   Based on field observations, methane emissions from the ESAS are less than 2.9 Tg per year.  Global methane emissions are around 550 Tg per year.  So even if the arctic emissions were to increase by ten-fold, they'll still be pretty low compared to other GHG emissions.

Not many scientists believe that is very likely with the warming in the oceans and land that we've seen to date.  These include scientists who have gone to the Arctic and measure the methane coming out of the methane seeps.

The ESAS is releasing at least 17 Tg, not 2.9.

https://www.sciencedaily.com/releases/2013/11/131125172113.htm
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Re: Arctic Methane Release
« Reply #763 on: December 01, 2018, 05:14:09 AM »
The ESAS is releasing at least 17 Tg, not 2.9.

https://www.sciencedaily.com/releases/2013/11/131125172113.htm

Different field studies give very different results.

Shakhova et al. 2014 says  17 Tg/yr
Berchet et al. 2016 says 0.0 to 4.5 Tg/yr
Thornton et al. 2016 says 2.9 Tg/yr

There are probably others I'm forgetting...

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Re: Arctic Methane Release
« Reply #764 on: December 01, 2018, 08:41:32 AM »
The ESAS is releasing at least 17 Tg, not 2.9.

https://www.sciencedaily.com/releases/2013/11/131125172113.htm

Different field studies give very different results.

Shakhova et al. 2014 says  17 Tg/yr
Berchet et al. 2016 says 0.0 to 4.5 Tg/yr
Thornton et al. 2016 says 2.9 Tg/yr

There are probably others I'm forgetting...

Quite maddening imo. Scientists need to get there shit together. We simply don’t have time to play games anymore. The public won’t take any of this seriously if we are so divided about certain individual things.
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Re: Arctic Methane Release
« Reply #765 on: December 01, 2018, 09:01:04 AM »

Quite maddening imo. Scientists need to get there shit together. We simply don’t have time to play games anymore. The public won’t take any of this seriously if we are so divided about certain individual things.

You are on the right track Wherestheice.  People who clearly know better are confusing the issues intentionally by mixing apples and oranges.  It is very frustrating!  That is why I don't comment on these forums anymore.  That is probably why many people don't comment on these forums anymore.

Read the papers, and you will have your answers.  Don't listen to what people on this forum tell you the papers say.  Study what the scientists actually did, and what they actually found.  You are right in your concerns and your understanding. 

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Re: Arctic Methane Release
« Reply #766 on: December 01, 2018, 09:10:20 AM »
Whereistheice, in the defense of scientists please remember lack of appropriate budgets. Humanity should have been spending billions monitoring the ESAS (and west Antarctica, and more), and then scientists would actually measure methane fluxes and be done with it. This is part of the reason for the different estimates.

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Re: Arctic Methane Release
« Reply #767 on: December 01, 2018, 09:24:40 AM »
I agree with Oren 100%.  He is someone you can always count on to give accurate and straight forward information! 

My post was not very clear.  I think the only way to get your answers is to study the actual papers. The scientists are great.  Where things get confusing is when people try to interpret what the papers mean.  Rather than accept someone else's interpretation, always read the paper yourself.   When you do, you will find that a lot of the "facts" being presented in this thread are actually BS. 

 

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Re: Arctic Methane Release
« Reply #768 on: December 01, 2018, 10:31:22 AM »
I agree with Oren 100%.  He is someone you can always count on to give accurate and straight forward information! 

My post was not very clear.  I think the only way to get your answers is to study the actual papers. The scientists are great.  Where things get confusing is when people try to interpret what the papers mean.  Rather than accept someone else's interpretation, always read the paper yourself.   When you do, you will find that a lot of the "facts" being presented in this thread are actually BS. 
Many papers are so technical that I get lost in them when trying to extract the message(s), even though at least I have a science background and many years of working as an analyst on many different subjects.

I rely on this forum for interpretations in plain English of these highly technical papers. The general public, most who have far less science education than I, need these plain English explanations even more.

Disagreements are inevitable and often beneficial. E.g. on methane undersea emissions there is a wide divergence of opinions and results from studies. The postings on this forum have made that clear, and also highlighted, as Oren pointed out, that science budgets for issues where life on earth may be at greatest peril, are starved of funds.
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Re: Arctic Methane Release
« Reply #769 on: December 01, 2018, 10:50:28 AM »
Part of my frustration is at folk relying on papers/data that arose prior to the past decade of rapid change?

They are sat looking at an image of a firework while the reality is that of the firework with the fuse fizzing and half spent?

Now the firework may prove to be a dud once the fuse reaches the main charge but surely we should be exploring just what we might expect if the firework is live and not just try to reassure ourselves with the old outdated image of the beast before the fuse was lit???
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Wherestheice

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Re: Arctic Methane Release
« Reply #770 on: December 01, 2018, 11:04:55 AM »
Whereistheice, in the defense of scientists please remember lack of appropriate budgets. Humanity should have been spending billions monitoring the ESAS (and west Antarctica, and more), and then scientists would actually measure methane fluxes and be done with it. This is part of the reason for the different estimates.

I agree, funding in the science department has always been lacking. Especially now, but at the same time scientists have done a horrible job of communicating the problem to the public. Many have made mistakes, the time has come to fix our errors.
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oren

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Re: Arctic Methane Release
« Reply #771 on: December 01, 2018, 04:58:24 PM »
Lurk thanks for the link to the 2018 Pankratova paper. Very interesting.

TerryM

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Re: Arctic Methane Release
« Reply #772 on: December 01, 2018, 07:35:03 PM »
A few comments in no particular order:


When S&S began their studies the reality of abiotic methane had still not been proven. Could the presence of abiotic seeps/plumes beneath the ESAS have an effect on their (and others) studies?


Bubble volume is dependent on depth. A bubble loses 50% of it's volume for ~each 10M of depth, or doubling of atmospheric pressure. Could this be a factor WRT the apparent viability of bubbles from 30 M shelves compared to those originating from deeper waters?


In anaerobic conditions organic material breaks down into CH4, among other things. I've difficulty understanding how CH4 is "oxidized" in anaerobic (no free oxygen) conditions. Anaerobic digesters are how man made bio-gas is produced, mimicking the natural production of biotic CH4.


Would studies of the sea floor of Hudson Bay's pingo like structures help in understanding what is to come in further north shallow seas such as the ESAS? My understanding is that the ice in Fox Inlet is noted as being dirty and muddied. I've long wondered if this could be the result of many pingo like structures exploding. - Besides, now that Harper is gone, the Canadian government might be willing to fund some (local) studies. ::)


Terry

SteveMDFP

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Re: Arctic Methane Release
« Reply #773 on: December 01, 2018, 07:56:14 PM »


In anaerobic conditions organic material breaks down into CH4, among other things. I've difficulty understanding how CH4 is "oxidized" in anaerobic (no free oxygen) conditions. Anaerobic digesters are how man made bio-gas is produced, mimicking the natural production of biotic CH4.
 

Seawater has abundant sulfate ions (SO4--).  In the absence of oxygen, some bacteria will use sulfate to oxidize methane.  The end products are CO2, water, and H2S.  Hydrogen sulfide is toxic to typical marine life.  But fortunately, we're just talking about what goes on in sediments here.

If/when the H2S-rich anaerobic water mixes with oxygenated water, other bacteria will convert the H2S to sulfate.  Sulfate is not toxic (depending on pH), and is ubiquitous in the sea.

oren

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Re: Arctic Methane Release
« Reply #774 on: December 02, 2018, 12:50:55 AM »
Sure, at Real Climate, you can type in Arctic Methane Release in the search box in the upper right-hand corner of the home page.  You'll get a lot of results.  Here's the one related to the Siberian holes (from 2014, but the science didn't change in two years):

http://www.realclimate.org/index.php/archives/2014/08/how-much-methane-came-out-of-that-hole-in-siberia/

Quote
Siberia has explosion holes in it that smell like methane, and there are newly found bubbles of methane in the Arctic Ocean. As a result, journalists are contacting me assuming that the Arctic Methane Apocalypse has begun. However, as a climate scientist I remain much more concerned about the fossil fuel industry than I am about Arctic methane. Short answer: It would take about 20,000,000 such eruptions within a few years to generate the standard Arctic Methane Apocalypse that people have been talking about. Here’s where that statement comes from:

How much methane emission is “a lot”? The yardstick here comes from Natalie Shakhova, an Arctic methane oceanographer and modeler at the University of Fairbanks. She proposed that 50 Gton of methane (a gigaton is 1015 grams) might erupt from the Arctic on a short time scale Shakhova (2010). Let’s call this a “Shakhova” event. There would be significant short-term climate disruption from a Shakhova event, with economic consequences explored by Whiteman et al Whiteman et al (2013). The radiative forcing right after the release would be similar to that from fossil fuel CO2 by the end of the century, but subsiding quickly rather than continuing to grow as business-as-usual CO2 does.

I and others have been skeptical of the possibility that so much methane could escape from the Arctic so quickly, given the century to millennial time scale of warming the permafrost and ocean sediments, and point out that if the carbon is released slowly, the climate impacts will be small. But now that explosion holes are being found in Siberia, the question is

How much methane came out of that hole in Siberia? The hole is about 80 meters in diameter and 60-100 meters deep.

It’s hard to say exactly how much methane did this, because perhaps the crater allowed methane to be released from the surrounding soil. There may be emissions in the future from permafrost melting laterally from the sides of the hole. But for a start let’s assume that the volume of the hole is the same as the volume of the original, now escaped, bubble. Gases are compressible, so we need to know what its pressure was. The deeper in the Earth it was, the higher the pressure, but if we are concerned about gas whose release might be triggered by climate warming, we should look for pockets that come close to the surface. Deep pockets might take thousands of years for surface warming to reach. The mass of a solid cap ten meters thick would increase the pressure underneath it to about four atmospheres, plus there may have been some overpressure. Let’s assume a pressure of ten atmospheres (enough to hold up the atmosphere plus about 30 meters of rock).

If the bubble was pure methane, it would have contained about … wait for it … 0.000003 Gtons of methane. In other words, building a Shakhova event from these explosions would take approximately 20,000,000 explosions, all within a few years, or else the climate impact of the methane would be muted by the lifetime effect.

The author of that post is David Archer.  He's a practicing climate scientist who studies the global carbon cycle, including methane hydrates.  You can read up on him at this website:

https://geosci.uchicago.edu/people/david-archer/

And here's a link to his paper on the methane cycle, permafrost, and hydrology of the Siberian continental margin:

https://www.biogeosciences.net/12/2953/2015/
This is a late response, and I am somewhat ashamed to be arguing with a prof. of David Archer's caliber, but I think this write-up suffers from a bad assumption, bolded and underlined above. How could the methane bubble have accumulated under pressure in that hole, if the hole was disconnected from its underground surroundings laterally and vertically? Obviously there was much more methane that escaped, and there's much more that will escape, from the hole's surroundings. Whether it's 10x or 100x the original volume I do not know, but it's certainly more probable than assuming just the amount in the original hole.
To use a (very poor) analogy, when the tap blows up, more water escapes than just in the immediate pipe.
If it's 100x the hole's volume, then you might not need 20M such holes, but only 200k. And if a catastrophic release is 10GT, rather than insisting on 50GT as a criterion, then you might need only 40k such holes - of which we had 7k in a short time per the information brought by G-W. Of course, some holes may be smaller, the gas may not be as pressurized as assumed by Archer, and the factor may not be 100x but much smaller, 10x or 2x or whatever. But I think to dismiss this out of hand and accept as fact that indeed 20M such holes are needed for a catastrophic release would be quite wrong IMHO, at least based on the quoted write-up.
Of course let's remember this is just an estimate of ground-based emissions, so adding up the sea-based emissions just makes this more of a risk. I am not saying the risk will necessarily materialize and in a catastrophic way, but I am saying that to assess this as "no risk" is scientifically wrong.

TerryM

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Re: Arctic Methane Release
« Reply #775 on: December 03, 2018, 04:57:28 AM »


In anaerobic conditions organic material breaks down into CH4, among other things. I've difficulty understanding how CH4 is "oxidized" in anaerobic (no free oxygen) conditions. Anaerobic digesters are how man made bio-gas is produced, mimicking the natural production of biotic CH4.
 

Seawater has abundant sulfate ions (SO4--).  In the absence of oxygen, some bacteria will use sulfate to oxidize methane.  The end products are CO2, water, and H2S.  Hydrogen sulfide is toxic to typical marine life.  But fortunately, we're just talking about what goes on in sediments here.

If/when the H2S-rich anaerobic water mixes with oxygenated water, other bacteria will convert the H2S to sulfate.  Sulfate is not toxic (depending on pH), and is ubiquitous in the sea.


Thanks Steve
The original claim was about anaerobic conditions under lakes, rather than the seafloor,
see #756 above.


Are SO4 ions as prevalent in freshwater as in seawater?


My experiences were limited to the development of enzyme producing bacteria in grey and black water septic (anaerobic) conditions. The purpose was to reduce (liquefy) solid waste and grease. The CH4 produced was a byproduct we weren't particularly interested in.


Others were capturing CH4 and were producing usable amounts from human waste when robust strains of bacteria were present. While I'm unaware of any degradation of CH4 under anaerobic conditions, it's was only an uninteresting byproduct in my operations.


Those that evolved the process into dairy and hog farms have since had success with commercial sized operations. I assume that if something was reducing their CH4 output they'd have needed to filter or treat the waste water, something that I don't believe they've engaged in.


The gal that's been firing off methane bubbles captured in Alaskan lake ice wouldn't be successful if the CH4 had been broken down in the anaerobic soils beneath the lake.
Terry


Ken Feldman

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Re: Arctic Methane Release
« Reply #776 on: December 03, 2018, 06:46:34 PM »
The ESAS is releasing at least 17 Tg, not 2.9.
https://www.sciencedaily.com/releases/2013/11/131125172113.htm

The 17 Tg comes from
Ebullition and storm-induced methane release from the East Siberian Arctic Shelf
Natalia Shakhova et al 2014
https://www.nature.com/articles/ngeo2007 (as per the article ref'd by WTI above)
That's abstract only/ppv

An early report on this paper said this in late 2013:

"The researchers note that their measurements contradict predictions by others that a massive "pulse" of methane will very soon add as much as 50 billion tonnes of methane to the atmosphere, causing a dramatic spike in global air temperatures.

Instead, they suggest, it appears more likely that the methane will continue to bubble up slowly, contributing to greenhouse gases much as is happening currently—though they do caution that its possible global warming could cause more or bigger storms in the Arctic Ocean, releasing methane on a bigger scale."


https://phys.org/news/2013-11-significant-amount-methane-east-siberian.html

So basically in agreement with what other scientist also publish.  David Archer's post in 2013 on Real Climate provides a good summary of S&S 2013 (and another paper on increased US emissions):

http://www.realclimate.org/index.php/archives/2013/11/arctic-and-american-methane-in-context/

Quote
The Context

Because methane is mostly well-mixed in the atmosphere, emissions from the Arctic or from the US must be seen within the context of the global sources of methane to the atmosphere. Estimates of methane emissions from the Arctic have risen, from land (Walter et al 2006) as well now as from the continental shelf off Siberia. Call it 20-30 Tg CH4 per year from both sources. The US is apparently emitting more than we thought we were, maybe 30 Tg CH4 per year. But these fluxes are relatively small compared to the global emission rate of about 600 Tg CH4 per year. The Arctic and US anthropogenic are each about 5% of the total. Changes in the atmospheric concentration scale more-or-less with changes in the chronic emission flux, so unless these sources suddenly increase by an order of magnitude or more, they won’t dominate the atmospheric concentration of methane, or its climate impact.



American Methane Emissions Higher Than Previously Thought

Miller et al (2013) combine measurements of methane concentrations in various locations through time with model reconstructions of wind fields, and “invert” the information to estimate how much methane was released to the air as it blew over the land. This is a well-established methodology, pushed to constrain US anthropogenic emissions by including measurements from aircraft and communications towers in addition to the ever-invaluable NOAA flask sample network, and incorporating socioeconomic and industrial data. The US appears to be emitting 50-70% more methane than the EPA thought we were, based on “bottom up” accounting (adding up all the known sources).

Is this bad news for global warming?

Not really, because the one real hard fact that we know about atmospheric methane is that it’s concentration isn’t rising very quickly. Methane is a short-lived gas in the atmosphere, so to make it rise, the emission flux has to continually increase. This is in contrast to CO2, which accumulates in the atmosphere / ocean system, meaning that steady (non-rising) emissions still lead to a rising atmospheric concentration. There is enough uncertainty in the methane budget that tweaks of a few percent here and there don’t upset the apple cart. Since the methane concentration wasn’t rising all that much, its sources, uncertain as they are, have been mostly balanced by sinks, also uncertain. If anything, the paper is good news for people concerned about global warming, because it gives us something to fix.

The Real Climate post has a very good overview of the ESAS, methane hydrate formation and dissolution and the potential of a sudden release of 50 billion tons of methane.  Here are some excerpts:

Quote
Is the methane flux from the Arctic accelerating?

Shakhova et al (2013) argue that bottom water temperatures are increasing more than had been recognized, in particular in near-coastal (shallow) waters. Sea ice cover has certainly been decreasing. These factors will no doubt lead to an increase in methane flux to the atmosphere, but the question is how strong this increase will be and how fast. I’m not aware of any direct observation of methane emission increase itself. The intensity of this response is pretty much the issue of the dispute about the Arctic methane bomb (below).

What about the extremely high methane concentrations measured in Arctic airmasses?

Shakhova et al (2013) show shipboard measurements of methane concentrations in the air above the ESAS that are almost twice as high as the global average (which is already twice as high as preindustrial). Aircraft measurements published last year also showed plumes of high methane concentration over the Arctic ocean (Kort et al 2012), especially in the surface boundary layer. It’s not easy to interpret boundary-layer methane concentrations quantitatively, however, because the concentration in that layer depends on the thickness of the boundary layer and how isolated it is from the air above it. Certainly high methane concentrations indicate emission fluxes, but it’s not straightforward to know how significant that flux is in the global budget.

The more easily interpretable measurement is the time-averaged difference between Northern and Southern hemisphere methane concentrations. If Arctic methane were driving a substantial increase in the global atmospheric methane concentration, it would be detectable in this time-mean interhemispheric gradient. Northern hemisphere concentrations are a bit higher than they are in the Southern hemisphere (here), but the magnitude of the difference is small enough to support the conclusion from the methane budget that tropical wetlands, which don’t generate much interhemispheric gradient, are a dominant natural source (Kirschke et al 2013).

Quote
What about that Arctic methane bomb?

Shakhova et al (2013) did not find or claim to have found a 50 Gt C reservoir of methane ready to erupt in a few years. That claim, which is the basis of the Whiteman et al (2013) $60 trillion Arctic methane bomb paper, remains as unsubstantiated as ever. The Siberian Arctic, and the Americans, each emit a few percent of global emissions. Significant, but not bombs, more like large firecrackers.


Ken Feldman

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Re: Arctic Methane Release
« Reply #777 on: December 03, 2018, 07:25:58 PM »
Sure, at Real Climate, you can type in Arctic Methane Release in the search box in the upper right-hand corner of the home page.  You'll get a lot of results.  Here's the one related to the Siberian holes (from 2014, but the science didn't change in two years):

http://www.realclimate.org/index.php/archives/2014/08/how-much-methane-came-out-of-that-hole-in-siberia/

Quote
Siberia has explosion holes in it that smell like methane, and there are newly found bubbles of methane in the Arctic Ocean. As a result, journalists are contacting me assuming that the Arctic Methane Apocalypse has begun. However, as a climate scientist I remain much more concerned about the fossil fuel industry than I am about Arctic methane. Short answer: It would take about 20,000,000 such eruptions within a few years to generate the standard Arctic Methane Apocalypse that people have been talking about. Here’s where that statement comes from:

How much methane emission is “a lot”? The yardstick here comes from Natalie Shakhova, an Arctic methane oceanographer and modeler at the University of Fairbanks. She proposed that 50 Gton of methane (a gigaton is 1015 grams) might erupt from the Arctic on a short time scale Shakhova (2010). Let’s call this a “Shakhova” event. There would be significant short-term climate disruption from a Shakhova event, with economic consequences explored by Whiteman et al Whiteman et al (2013). The radiative forcing right after the release would be similar to that from fossil fuel CO2 by the end of the century, but subsiding quickly rather than continuing to grow as business-as-usual CO2 does.

I and others have been skeptical of the possibility that so much methane could escape from the Arctic so quickly, given the century to millennial time scale of warming the permafrost and ocean sediments, and point out that if the carbon is released slowly, the climate impacts will be small. But now that explosion holes are being found in Siberia, the question is

How much methane came out of that hole in Siberia? The hole is about 80 meters in diameter and 60-100 meters deep.

It’s hard to say exactly how much methane did this, because perhaps the crater allowed methane to be released from the surrounding soil. There may be emissions in the future from permafrost melting laterally from the sides of the hole. But for a start let’s assume that the volume of the hole is the same as the volume of the original, now escaped, bubble. Gases are compressible, so we need to know what its pressure was. The deeper in the Earth it was, the higher the pressure, but if we are concerned about gas whose release might be triggered by climate warming, we should look for pockets that come close to the surface. Deep pockets might take thousands of years for surface warming to reach. The mass of a solid cap ten meters thick would increase the pressure underneath it to about four atmospheres, plus there may have been some overpressure. Let’s assume a pressure of ten atmospheres (enough to hold up the atmosphere plus about 30 meters of rock).

If the bubble was pure methane, it would have contained about … wait for it … 0.000003 Gtons of methane. In other words, building a Shakhova event from these explosions would take approximately 20,000,000 explosions, all within a few years, or else the climate impact of the methane would be muted by the lifetime effect.

The author of that post is David Archer.  He's a practicing climate scientist who studies the global carbon cycle, including methane hydrates.  You can read up on him at this website:

https://geosci.uchicago.edu/people/david-archer/

And here's a link to his paper on the methane cycle, permafrost, and hydrology of the Siberian continental margin:

https://www.biogeosciences.net/12/2953/2015/
This is a late response, and I am somewhat ashamed to be arguing with a prof. of David Archer's caliber, but I think this write-up suffers from a bad assumption, bolded and underlined above. How could the methane bubble have accumulated under pressure in that hole, if the hole was disconnected from its underground surroundings laterally and vertically? Obviously there was much more methane that escaped, and there's much more that will escape, from the hole's surroundings. Whether it's 10x or 100x the original volume I do not know, but it's certainly more probable than assuming just the amount in the original hole.
To use a (very poor) analogy, when the tap blows up, more water escapes than just in the immediate pipe.
If it's 100x the hole's volume, then you might not need 20M such holes, but only 200k. And if a catastrophic release is 10GT, rather than insisting on 50GT as a criterion, then you might need only 40k such holes - of which we had 7k in a short time per the information brought by G-W. Of course, some holes may be smaller, the gas may not be as pressurized as assumed by Archer, and the factor may not be 100x but much smaller, 10x or 2x or whatever. But I think to dismiss this out of hand and accept as fact that indeed 20M such holes are needed for a catastrophic release would be quite wrong IMHO, at least based on the quoted write-up.
Of course let's remember this is just an estimate of ground-based emissions, so adding up the sea-based emissions just makes this more of a risk. I am not saying the risk will necessarily materialize and in a catastrophic way, but I am saying that to assess this as "no risk" is scientifically wrong.

Oren,

To get the pressure required to blow the top off of the hole, methane hydrates would need to melt (one liter of methane hydrates contain about 169 liters of methane gas).  That would result in the sudden release of methane into the atmosphere, which is the volume that Archer calculated.

The gradual leaking of methane through the soil, to the crater (and eventually the lake that would form in the crater) would be similar to current rates of methane release.  It would be subject to chemical reactions and digestion from bacteria, and would be gradually released, so it's difficult to see how it could be 10 to 100 times the initial volume from the melted hydrates.

Ken Feldman

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Re: Arctic Methane Release
« Reply #778 on: December 03, 2018, 08:30:33 PM »
Quote
But worst of all - climate scientists do not even speak to each other as a matter of course - as a prerequisite before writing up their own papers which criticize and dismiss the findings in others' papers.

Not sure what gives you this idea.  There are many meetings throughout the year at which climate scientist discuss their findings face-to-face.  AGU, EGU and others.  Here's a summary of an AGU meeting from several years ago:

http://www.realclimate.org/index.php/archives/2011/12/agu-2011-day-5-and-wrap-up/

Quote
Looking back at the whole meeting (20,000+ scientists, dozens of simultaneous sessions), it is perhaps worth noting the reasons why such meetings are so important. Obviously, no-one can see everything that is relevant to their research, or talk to everyone they might want to, but there is a lot that can be seen and absorbed much more efficiently than would be possible at home. The social aspect of conferences is also important – beer is an essential lubricant for geophysicists it seems. More important than the sessions are often the chance encounters on the escalators or corridors. Many people get to meet in person who only ever emailed – and this includes other bloggers as well as scientists. We met Eli Rabett, John Cook (Skeptical Science), Zeke Hausfather, Kate @ ClimateSight, Steve Easterbrook, and many others who are only known by their screen names and comments. Many of the scientists whose work has been discussed here recently were also present – Andreas Schmittner, Robert Rohde (of BEST), Jim Hansen, Ben Santer, Roy Spencer, along with many, many first timers whose work will become more prominent. The palpable sense of excitement at the directions the science is taking is very much driven by the bright ideas and new approaches being generated by the younger scientists – including undergraduates and graduate students. And it is the serendipitous encounters with these new voices that are the most unanticipated (and unplanned) benefits of these meetings. This doesn’t happen with Skype unfortunately.

And there are special meetings held at institutions where the research is done.  Here's a summary of one such meeting:

https://eos.org/meeting-reports/resolving-a-methane-mystery-in-the-arctic

Quote
Methane (CH4) is a powerful greenhouse gas with the potential to accelerate climate change if emissions substantially increase. Models based on numerous field studies in recent decades estimate large CH4 emissions from wetlands, lakes, and marine shelf environments in the northern permafrost region.

The sum of these emission estimates is about 60 teragrams CH4 per year, or ~25% of global natural CH4 emissions. This is substantially larger than the ~25 teragrams CH4 per year emissions estimated for the region from inversion models based on atmospheric CH4 concentration data. Thus, there is a clear need for the scientific community to resolve this discrepancy and better understand the sensitivity of CH4 emissions to ongoing climate change in the northern permafrost region.

A workshop was convened in March to facilitate reconciling estimates based on field measurements and inversion models. It was organized by the Study of Environmental Arctic Change (SEARCH) and funded by the National Science Foundation, NASA, the U.S. Geological Survey, and the U.S. Arctic Research Commission. Forty-two scientists from around the world, with diverse expertise in CH4 dynamics, attended the workshop.

The first day of the workshop included keynote presentations providing atmospheric, inland (wetlands, lakes, and rivers), marine, and remote sensing perspectives on CH4 budgets in the region. The atmospheric presentations identified that forward and inverse models fail to accurately estimate cold season emissions. A crucial question raised was why CH4 emissions in this region have been stable over recent decades, whereas many process-based models indicate that increasing temperatures should have led to a detectable increase in emissions. Key issues identified in inland and marine presentations included the need to standardize the spatial domain, minimize double counting of emissions from lakes and wetlands, reduce bias in field site selections, improve measurements of cold season emissions, and improve scaling of hot spots.

During the second day, breakout groups identified key uncertainties and developed plans for addressing them in several near-term and long-term activities. The near-term activities include developing a cross-disciplinary road map for reconciling estimates between models based on field observations and atmospheric data, compiling existing atmospheric observations, synthesizing cold season emissions as well as lake ebullition data, comparing CH4 processes and emissions estimates among the shelves of the Arctic Ocean, and analyzing scaling methodologies. Long-term activities include determining the sensitivities of CH4 emissions to climate variability and change in the region, evaluating the detectability of changes in CH4 dynamics, and developing enhancements to the CH4 observation network to improve trend detection.

The road map for reconciling observations and models will be completed by the end of this year. Workshop teams will make progress on other near-term activities with the intention of completing them by the end of 2018. Substantive progress on long-term activities is expected in the next 3 to 5 years. The SEARCH Permafrost Action Team will track the progress of the workshop’s follow-on activities and will develop research summaries and briefs.

Ken Feldman

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Re: Arctic Methane Release
« Reply #779 on: December 03, 2018, 08:34:59 PM »
This study will be discussed at the upcoming AGU meeting (December 10 - 14 in Washington, DC):

https://agu.confex.com/agu/fm18/meetingapp.cgi/Paper/432674

Quote
Future concentrations of greenhouse gases (GHGs) in the atmosphere will determine the degree of warming the Earth will experience. Atmospheric methane, a powerful GHG, is controlled primarily by its anthropogenic and natural emissions and its destruction in the atmosphere. Natural methane emissions are noticeably influenced by warming of cold arctic ecosystems and permafrost. An evaluation specifically of Arctic natural methane emissions in relation to our ability to mitigate anthropogenic methane emissions is needed. Here we use empirical scenarios of increases in natural emissions together with maximum technically feasible reductions in anthropogenic emissions to evaluate their potential influence on future atmospheric methane concentrations and associated radiative forcing (RF). The largest amplification of natural emissions yields up to 42% higher atmospheric methane concentrations by the year 2100 compared with no change in natural emissions. The most likely scenarios are lower than this, while anthropogenic emission reductions may have a much greater yielding effect, with the potential of halving atmospheric methane concentrations by 2100 compared to when anthropogenic emissions continue to increase as in a business-as-usual case. In a broader perspective, it is shown that man-made emissions can be reduced sufficiently to limit methane-caused climate warming by 2100 even in the case of an uncontrolled natural Arctic methane emission feedback, but this requires a committed effort towards maximum feasible reductions.

Pmt111500

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Re: Arctic Methane Release
« Reply #780 on: December 04, 2018, 05:13:42 AM »
 if the normal oxygen deprivation under lake ice during winter can occur also on the continental shelves, there could be quite a burb of gassy stuff to the atmosphere in some spring. Those microbes using up the slower seeps of fizzy sea water still need oxygen to power their one-carbon cycle of energy. Well OK, there are also the anaerobic pathways (AOM) which would require quite specific circumstances to be effective,
« Last Edit: December 04, 2018, 05:49:49 AM by Pmt111500 »
Amateur observations of Sea Ice since 2003.

Ken Feldman

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Re: Arctic Methane Release
« Reply #781 on: December 04, 2018, 08:00:28 PM »
Here's a link to the first paper (results of a survey of 40 scientists done in 2009).

https://cloudfront.escholarship.org/dist/prd/content/qt3c84h27d/qt3c84h27d.pdf

Some excerpts:

Quote
The survey was filled out by a group of 40 international scientists, including myself, who publish on various aspects of permafrost. The results are striking. We collectively hypothesize that the high warming scenario will degrade 9-15% of the top 3 metres of permafrost by 2040, increasing to 47-61% by 2100 and 67-79% by 2300. Ranges represent 95% confidence intervals around the mean estimate of the collective group. The estimated carbon release from this degradation is 30-63 billion tonnes of carbon over the next three decades, reaching 234-380 billion tonnes by 2100 and 549-865 billion tonnes over the next several centuries. These values, expressed in billions of tons of carbon in CO2 equivalents, combine the effect of carbon released both as CO2 and as CH4.

Here's a free version of the second linked paper:

http://whrc.org/wp-content/uploads/2015/09/SchuuretalNature.15.pdf

Here's an excerpt from the introduction (with emphasis added):

Quote
Bringing together this wealth of new observations, we propose that greenhouse
gas emissions from warming permafrost are likely to occur at a magnitude
similar to other historically important biospheric carbon sources
(such as land-use change) but that will be only a fraction of current fossil-fuel
emissions. At the proposed rates, the observed and projected emissions of
CH4 and CO2 from thawing permafrost are unlikely to cause abrupt climate
change over a period of a few years to a decade
. Instead, permafrost carbon
emissions are likely to be felt over decades to centuries as northern regions
warm, making climate change happen faster than we would expect on the
basis of projected emissions from human activities alone. This improved
knowledge of the magnitude and timing of permafrost carbon emissions
based on the synthesis of existing data needs to be integrated into policy
decisions about the management of carbon in a warming world, but at the
same time may help temper the worst fears about the impact of carbon
emissions from warming northern high-latitude regions
.

It would appear that the 2015 study (Lurk's second link) including a "wealth of new observations" contradicts the 2009 survey of 40 scientists (Link's first link). 

Edit:  It's interesting to note that the first author on both of these papers is the same.  It's E.A.G. Schuur.  Good to see that they followed up on their guesses from the survey by summarizing more recent observations and publishing the results.


« Last Edit: December 04, 2018, 08:36:52 PM by Ken Feldman »

Wherestheice

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Re: Arctic Methane Release
« Reply #782 on: December 04, 2018, 08:58:33 PM »
Here's a link to the first paper (results of a survey of 40 scientists done in 2009).

https://cloudfront.escholarship.org/dist/prd/content/qt3c84h27d/qt3c84h27d.pdf

Some excerpts:

Quote
The survey was filled out by a group of 40 international scientists, including myself, who publish on various aspects of permafrost. The results are striking. We collectively hypothesize that the high warming scenario will degrade 9-15% of the top 3 metres of permafrost by 2040, increasing to 47-61% by 2100 and 67-79% by 2300. Ranges represent 95% confidence intervals around the mean estimate of the collective group. The estimated carbon release from this degradation is 30-63 billion tonnes of carbon over the next three decades, reaching 234-380 billion tonnes by 2100 and 549-865 billion tonnes over the next several centuries. These values, expressed in billions of tons of carbon in CO2 equivalents, combine the effect of carbon released both as CO2 and as CH4.

Here's a free version of the second linked paper:

http://whrc.org/wp-content/uploads/2015/09/SchuuretalNature.15.pdf

Here's an excerpt from the introduction (with emphasis added):

Quote
Bringing together this wealth of new observations, we propose that greenhouse
gas emissions from warming permafrost are likely to occur at a magnitude
similar to other historically important biospheric carbon sources
(such as land-use change) but that will be only a fraction of current fossil-fuel
emissions. At the proposed rates, the observed and projected emissions of
CH4 and CO2 from thawing permafrost are unlikely to cause abrupt climate
change over a period of a few years to a decade
. Instead, permafrost carbon
emissions are likely to be felt over decades to centuries as northern regions
warm, making climate change happen faster than we would expect on the
basis of projected emissions from human activities alone. This improved
knowledge of the magnitude and timing of permafrost carbon emissions
based on the synthesis of existing data needs to be integrated into policy
decisions about the management of carbon in a warming world, but at the
same time may help temper the worst fears about the impact of carbon
emissions from warming northern high-latitude regions
.

It would appear that the 2015 study (Lurk's second link) including a "wealth of new observations" contradicts the 2009 survey of 40 scientists (Link's first link). 

Edit:  It's interesting to note that the first author on both of these papers is the same.  It's E.A.G. Schuur.  Good to see that they followed up on their guesses from the survey by summarizing more recent observations and publishing the results.

Even note recent research concludes that 20% of surface permafrost may melt by 2040.

https://www.amap.no/swipa
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Ken Feldman

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Re: Arctic Methane Release
« Reply #783 on: December 04, 2018, 11:52:37 PM »
Here's a link to the 2017 update of the SWIPA assessment (Where's the ice linked to the older report from 2011 in his post above):

https://www.amap.no/swipa2017

Here's the summary of expected changes to the snow cover and permafrost from the fact sheets released to the media:

Quote
Snow and Permafrost
The duration of snow cover is projected to decrease by
an additional 10–20% from current levels over most of
the Arctic by mid-century under a high emissions
scenario, and the area of near-surface permafrost is
projected to decrease by around 35%
under the same
scenario. Areas with relatively warmer climates, such as
Scandinavia and coastal Alaska, are most at risk for
declining snow cover. (Chapter 3, Snow and Chapter 4,
Permafrost)

As with sea ice, volume is the key metric.  In some parts of Siberia, the permafrost layer is 1500 meters thick!  So if the surface permafrost melts, it's only releasing a small fraction of the methane that the layer contains.  Since methane decays quickly in the atmosphere (within a decade), a large amount of the permafrost would have to melt relatively quickly to produce an abrupt climate change.

In the report's summary of the key findings, it states (emphasis added),

Quote
This assessment shows increased confirmation that the
Arctic is now considerably different from the Arctic of the late
20th century. Chapter 2 considers the Arctic system as a whole
and addresses consilience: when multiple sources of evidence
are in agreement, conclusions can lead to scientific consensus
even when individual sources of evidence are less conclusive
on their own. New thresholds since the previous SWIPA
assessment (conducted 2008–2011) are established when a
time series representing Arctic processes obtains new record
values. ese thresholds can be from trends (e.g. continuous
change like increasing temperatures or declining spring snow
cover) or as a regime shi when there is a qualitative change
in the structure of the basic system, such as transitions from
multi-year to first-year sea ice and coniferous to deciduous
boreal forests. ere are clear irreversible changes such as
permafrost thaw and coastal melting of the Greenland Ice
Sheet. Current evidence for a tipping point (a run-away
condition based on internal climate physics) is not seen.
Section 10.2 does discuss potential tipping points at other
times such as abrupt warming and cooling during the previous
glacial period (13,000 years BP) and for the late 21st century.


Cid_Yama

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Re: Arctic Methane Release
« Reply #784 on: December 05, 2018, 07:51:48 AM »
He's been comparing apples to oranges the whole time.  Abrupt Climate Change is real and reflected in the ice and sediment cores.
 


You think IPCC is political, The SWIPA update to their 2011 report is even more so, since the Arctic Council members (except the Inuits) are pursuing fossil fuel exploitation in the Arctic.   
« Last Edit: December 05, 2018, 08:30:31 AM by Cid_Yama »
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Wherestheice

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Re: Arctic Methane Release
« Reply #785 on: December 05, 2018, 08:37:23 AM »
He's been comparing apples to oranges the whole time.  Abrupt Climate Change is real and reflected in the ice and sediment cores.
 


You think IPCC is political, The SWIPA update to their 2011 report is even more so, since the Arctic Council members (except the Inuits) are pursuing fossil fuel exploitation in the Arctic.

No longer is it climate change denial, it is abrupt climate change denial
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Ken Feldman

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Re: Arctic Methane Release
« Reply #786 on: December 06, 2018, 06:39:31 PM »
If you watch those videos on abrupt climate change, around the 8:00 mark there's a slide summarizing the abrupt changes.

It  has a bullet stating: "Others concerning, but not abrupt:  permafrost melting"

And at the 8:10 mark, he addresses the permafrost melting directly and says it's not abrupt, it "probably has brakes on it".


Wherestheice

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Re: Arctic Methane Release
« Reply #787 on: December 06, 2018, 07:49:03 PM »
If you watch those videos on abrupt climate change, around the 8:00 mark there's a slide summarizing the abrupt changes.

It  has a bullet stating: "Others concerning, but not abrupt:  permafrost melting"

And at the 8:10 mark, he addresses the permafrost melting directly and says it's not abrupt, it "probably has brakes on it".

Well the permafrost is thawing quite abruptly, especially in recent years. I suggest looking at the actual observations in the field. Because it’s clear what’s going on here. The denial of this stuff is insane.

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Gray-Wolf

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Re: Arctic Methane Release
« Reply #788 on: December 06, 2018, 09:01:09 PM »
We got the expert in the field telling us that the summer of 2019 will see the (now) 7,000 plus 'Pingo like structures' go kaboom so maybe we can afford a six month lay off and the re-ask the questions of the denier?
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Ken Feldman

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Re: Arctic Methane Release
« Reply #789 on: December 06, 2018, 09:21:11 PM »
Are you calling David Archer, the IPCC, other Arctic researchers who've found lower levels of methane release than S&S deniers? 

Wherestheice

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Re: Arctic Methane Release
« Reply #790 on: December 06, 2018, 10:49:50 PM »
Are you calling David Archer, the IPCC, other Arctic researchers who've found lower levels of methane release than S&S deniers?

The IPCC is way way to conservative. They ignore self reinforcing feedback loops. Their information is diluted under politics and intense speculation. David Archer is not a specialist in the Arctic. He works at the university of Chicago.

And then there is this.....
“The risk of large-scale releases of the deadly greenhouse gas, methane, from the East Siberian Arctic Shelf (ESAS) may be a subject of debate in the scientific community, but to purposefully exclude one side of the debate and openly denounce their findings is not just immoral, it is reckless.”

https://envisionation.co.uk/index.php/blogs/99-russian-scientists-excluded-from-presenting-important-research-as-nasa-goddard-director-tries-to-discredit-observational-scientific-research

I fear a lot of research into the Arctic has been held back or shut down

https://robertscribbler.com/2014/10/15/ignoring-the-arctic-methane-monster-royal-society-goes-dark-on-arctic-observational-science/

Recent research suggests that ice melt Can cause methane hydrates to release, and it may have happened in the past.

http://science.sciencemag.org/content/356/6341/948

I could go on and on with very much evidence. The thing is, it’s not just S&S who think the methane release threat is real. It’s very many scientists. To answer your question yes. I think those people and the IPCC are deniers. It comes down to are you gonna look at data and observations from people who have spent decades up there, or a bunch of models and people that create those models that insist they must not be wrong. We are on the brink of catastrophic collapse of the planet. If we want to save humanity we need to be wise about all possible threats. Saying the methane release won’t happen and is nothing to worry about is insanity.
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Re: Arctic Methane Release
« Reply #791 on: December 07, 2018, 04:11:20 AM »
.....denial......
Da Nile flows north, but I didn't think, all the way to Siberia.

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Re: Arctic Methane Release
« Reply #792 on: December 07, 2018, 12:17:05 PM »
Yes, and the only way he could take away what he claims from the Jim White video is he is in denial or intentionally misrepresenting and spreading disinformation (which is my take of what he is doing).

There is a guy over on peakoil.com named RockDoc who twists things in exactly the same manner, been doing it for years, like he gets paid to do it.

First off, the video was in 2014, before we started getting the methane blowouts on land, and second, terrestrial permafrost and subsea relic permafrost on the ESAS are like apples and oranges.  (although with regards to the pingo-like-features, that is pretty much the same process. Free methane under pressure finding areas where the permafrost is weakened and pushing upward.)

Also, Semiletov is the director of the Far Eastern branch of the Russian Academy of Sciences.  It isn't just him and his wife.  It's dozens of scientist working under him as well as almost as many international researchers that work with him.

They are the ones doing the actual on site research and collecting the data.  Archer (who he keeps quoting from his papers from the mid 2000s) and Gavin Schmidt definitely are not and never have.  They are climate modelers.         
« Last Edit: December 07, 2018, 12:46:35 PM by Cid_Yama »
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Re: Arctic Methane Release
« Reply #793 on: December 07, 2018, 02:51:29 PM »
So it's kinda like a person staring at the GFS to see what the weather is like instead of going to the door and looking outside?

I think we have similar occurring now with changes to the circulation in the upper trop/lower strat ( esp. with the polar night Jet and its positioning/forcings?)  with 'realtime events' now overwriting the old given wisdoms?

We are no longer predicting what change will be like but actually seeing it beginning to impact.

What good are the " Calm down it's never going to happen like that" posts when we are sat watching it happen like that?

If Semiletov is correct in his timings for the eruption of the 'Pingo Like Structures' then folk do not have too long to wait for a definitive answer to the question of whether we should expect 'spikes' in CH4 under current warming?

With a renewed Nino pulse also forecast for jan/feb maybe we will see higher than average global temps further add into northern melt this coming year?
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gerontocrat

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Re: Arctic Methane Release
« Reply #794 on: December 07, 2018, 04:12:59 PM »
Cautionary note

The Russian papers never actually commit to even a ballpark figure of possible increases in CH4 emissions from our current AGW pathway. I think the word significant is used somewhere, as is the possibility or probability that the tipping point for those significant releases to start is very nearly upon us.

One GT of CH4 at 50 bar pressure (at around 0 celsius) would occupy about 24 km3, at 10 bar 140 km3, and at 1 bar (atmospheric pressure) about 1400 km3.

I wonder what volume of gas would be released from 7,000 pingos going poof ?
I wonder what sort of pressure free CH4 is at under the permafrost lid of the ESAS (and inside the pingos)?

I still think that a lot of additional CH4 is going to be released from the Arctic, but will it be tons, megatons, gigatons, and when?
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Re: Arctic Methane Release
« Reply #795 on: December 07, 2018, 04:38:47 PM »
I'd agree gerontocrat, what we do know is we are seeing changes , both in the wetlands and the permafrost, that point toward increased CH4 outputs?

What would be nice to know is just how much 'free methane' we have capped by the permafrost and whether the reserve is in any way interlinked, either by cavities in the strata or existing fault planes?

Does any methane outburst pose a threat of degassing the reserve if that outburst forms a suitable 'pathway' to the atmosphere for it?

If Yamal is as primed to go pop as we are warned then I guess we are about to answer some of the above questions?
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Ken Feldman

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Re: Arctic Methane Release
« Reply #796 on: December 07, 2018, 08:04:12 PM »
Here's a link to a 2015 study on the Kara Sea permafrost adjacent to the Yamal Pennisula.  They drilled into several pingo-like formations (PLF) to determine the amount of methane in the PLFs:

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2015JF003467

It provides a brief history of the permafrost formation that area and the rates of permafrost thawing that has occurred.  Here's the abstract and some excerpts:

Quote
Methane release from pingo‐like features across the South Kara Sea shelf, an area of thawing offshore permafrost

Quote
There are two competing hypotheses for the conditions under which pingo‐like formations (PLFs) form: (1) an early study suggests that they formed under terrestrial conditions in low relative sea level stands during glacial episodes throughout the late Pleistocene and were subsequently submerged in interglacials [Shearer et al., 1971] or, alternatively, (2) that they developed in marine environments after the shelf flooding in Holocene times [Bondarev et al., 2002; Paull et al., 2007]. Earlier models of marine PLF formation speculated that gas, emitted during dissociation of gas hydrates within and below thawing permafrost, built up at high pressures driving seafloor doming [Paull et al., 2007]. However, the debate is still ongoing as to whether PLFs are related to gas release since many of the documented PLFs do not reveal any measurable gas discharge [Bondarev et al., 2002; Paull et al., 2007].

Steady state gas leakage and even blowout events have been documented from some of the PLFs at the Beaufort Sea and Russian Arctic shelves [Hovland et al., 1993; Judd and Hovland, 2007]. Noteworthy, a drilling vessel (operated by “AMIGE” company) experienced an emergency situation due to sudden and extensive gas release from a well after the drill bit penetrated a gas pocket inside a large PLF in the Pechora Sea [Bondarev et al., 2002; Rokos, 2008]. Hence, it follows that some PLFs act as major gas storage and seepage hot spots. The recently described Siberian craters found onshore in permafrost regions of the Yamal Peninsula have also been speculated to be the result of accumulation of high gas pressure and abrupt methane release [Bogoyavlenskiy, 2014a, 2014b; Moskvitch, 2014].

Quote
2.2 Permafrost Settings and Gas Hydrate Stability

Reconstructions of the Barents‐Kara ice sheet extent reveal that a large part of the South Kara Sea shelf was ice‐free and exposed to subaerial conditions during the Late Weichselian [Polyak et al., 2008; Svendsen et al., 2004] (Figure 1a). The sustained cold temperatures to −20°C that prevailed over this extended period [Romanovskii et al., 2003] led to extensive and deep permafrost generation. Drilling results indicate the presence of a more than 300 m thick permafrost layer onshore Yamal Peninsula [Melnikov and Spesivtsev, 1995]. Subsea permafrost was discovered in individual boreholes of the South Kara Sea in water depth of up to 115 m. Modeling of permafrost generation at the South Kara Sea shelf suggests that a 275–480 m thick permafrost layer occurred during the LGM [Portnov et al., 2014; Rokos et al., 2009]. Such sustained, frozen temperatures provide ideal conditions for the formation of gas hydrates within and beneath the permafrost where methane is present (Figure 2) [Collett et al., 2011; Ruppel, 2007].

Quote
Such distinct bottom water warming impacts on the subsea permafrost through thermal diffusion and eventually propagates through to the top of the gas hydrate stability zone (GHSZ) [Sloan, 1998]. Portnov et al. [2014] notes that an equilibrium temperature distribution within subsea permafrost establishes itself at ~1000 years after flooding (geothermal heat flux and bottom water temperature are taken as 0.07 W m−2 and −0.5°C, respectively). Differences in geothermal heat flux values significantly affect the depth path of freezing during the global sea regression and what remains from subsea permafrost thickness and GHSZ at the present time (Figure 2) [Portnov et al., 2014; Taylor et al., 2013; Nicolsky et al., 2012]. A few existing heat flux records from the South Kara Sea shelf show values ranging from 0.054 to 0.076 W m−2 [Khutorskoy and Podgornyh, 2010].

Such variation implies contrasting scenarios of permafrost and GHSZ evolution. Under the elevated geothermal heat flux (0.07 W m−2), continuous permafrost at 40 m below sea level (bsl) will have completely thawed and the corresponding GHSZ should have completely diminished (Figure 2a). Under the moderate geothermal heat flux (0.06 W m−2) ~100 m thick permafrost can still exist at 40 m bsl water depths. However, its lower boundary is too shallow to provide temperatures low enough for gas hydrates to be stable (Figure 2b). Finally, under 0.05 W m−2 heat flux scenario permafrost may still be >150 m thick, providing intrapermafrost and subpermafrost GHSZ in the study area (Figure 2c).

Here are their conclusions:

Quote
Pingo‐like features (PLFs) exist across the South Kara Sea in ~40 m water depth. One PLF (PLF 2) connects to biogenic gas from deeper sources. Integrated geochemical and geophysical studies suggest that the PLFs evolved after the Last Glacial Maximum and during the Holocene sea level transgression that flooded extensive areas of the Arctic continental shelves. The formation of one PLF (PLF 2) is directly linked to the thawing of subsea permafrost and decomposition of permafrost‐related gas hydrates. High accumulations of biogenic methane create the necessary forces to push the remaining frozen layers upward. We speculate that PLF 1 is either a relict‐submerged terrestrial pingo or a PLF lacking the necessary underlying methane accumulations. More detailed grid‐pattern HRS and drill site investigations are needed to determine the complex distribution patterns of the South Kara Sea PLFs.

TLDR version:  Pingo like formations (PLFs) have been around since the Last Glacial Maximum.  Not all PLFs contain methane or are linked to free gas under the PLF.  Each PLF needs to be investigated (drilled into) to determine whether it has methane gas or is just water ice.

Ken Feldman

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Re: Arctic Methane Release
« Reply #797 on: December 07, 2018, 08:46:46 PM »
Cautionary note

The Russian papers never actually commit to even a ballpark figure of possible increases in CH4 emissions from our current AGW pathway. I think the word significant is used somewhere, as is the possibility or probability that the tipping point for those significant releases to start is very nearly upon us.

One GT of CH4 at 50 bar pressure (at around 0 celsius) would occupy about 24 km3, at 10 bar 140 km3, and at 1 bar (atmospheric pressure) about 1400 km3.

I wonder what volume of gas would be released from 7,000 pingos going poof ?
I wonder what sort of pressure free CH4 is at under the permafrost lid of the ESAS (and inside the pingos)?

I still think that a lot of additional CH4 is going to be released from the Arctic, but will it be tons, megatons, gigatons, and when?

David Archer provided the calculations (based on simple math and gas laws, not models) you're wondering about.  Once again, here's the link to his post where he provides his calculations:

http://www.realclimate.org/index.php/archives/2014/08/how-much-methane-came-out-of-that-hole-in-siberia/comment-page-3/

Based on the size of the crater and assuming that it was pressure from melting methane hydrates that caused the crater, the immediate release of methane from the eruption would have been 0.000003 Gt.  If 7,000 PLFs of the same size erupted next summer, they would release 0.021 Gt of methane from the eruption alone.  Some gas could continue to seep out from the sides of the crater after the eruption too.  If you double the amount, you still only end up with 0.042 Gt of methane.

According to the IPCC, global methane emissions in 2011, as reported in AR5 Chapter 6, were 556 Gt.  (Edit: should by 556 Mt, not Gt).

S&S calculated annual methane emissions from the ESAS based on their studies of 0.0179 Gt.  Other studies over different parts of the ESAS found lower amounts (0.0029 Gt).

There have been instances of abrupt climate change in the past.  It doesn't appear that methane emissions from the Arctic are going to cause an abrupt climate change in the next few decades, let alone next summer.

Edit, as Geroncrat reminded me below, global methane emissions are 555 million tons (Mt), not billion tons (Gt).
« Last Edit: December 08, 2018, 12:12:24 AM by Ken Feldman »

gerontocrat

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Re: Arctic Methane Release
« Reply #798 on: December 07, 2018, 09:18:08 PM »
According to the IPCC, global methane emissions in 2011, as reported in AR5 Chapter 6, were 556 Gt.

Surely Million Tons, not GT?
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Re: Arctic Methane Release
« Reply #799 on: December 07, 2018, 10:08:05 PM »
According to the IPCC, global methane emissions in 2011, as reported in AR5 Chapter 6, were 556 Gt.

Surely Million Tons, not GT?

Oops, you're right, total global methane emissions were 555 Million tons, not Billion tons.  I accidently confused it with the CO2 emissions, which were around 10 Billion tons per year in 2011.

7,000 Pingo Like Features on land erupting in the same year would be 2.9 million tons of methane, or about one-half of one percent of global emissions.


Link to AR5, Chapter 6:

http://www.climatechange2013.org/images/report/WG1AR5_Chapter06_FINAL.pdf

and to the full report here:

http://www.climatechange2013.org/report/full-report/