Arctic Methane Release

[Alumril]

Kassy, so I had a think about this, and tried to come up with sites that are more likely to have increased in methane faster than the global average.
I tried Niwot Ridge, Colorado, United States (NWR) due to the local fracking activity and Mt. Waliguan, Peoples Republic of China (WLG) due to increased rice production and increased industrial activity. I don't have any local knowledge of these places, so it was a bit of a guess.

There is a slight increased trend on both sites vs south pole data. While the trend for Barrow  (BRW) is flat.

Now I did deliberately pick these sites because I thought would have the largest increase in emissions. But then I originally expected to see the same trend in Barrow and Tiksi and didn't find it.

I'm no expert on this, so I'm happy for any challenge of these methods.

[morganism]

great pics of methane bubbles frozen in ice

https://siberiantimes.com/other/others/features/beauty-of-frozen-methane-bubbles-on-the-worlds-deepest-lake-shown-in-stunning-video/

[ArgonneForest]

Kassy, so I had a think about this, and tried to come up with sites that are more likely to have increased in methane faster than the global average.
I tried Niwot Ridge, Colorado, United States (NWR) due to the local fracking activity and Mt. Waliguan, Peoples Republic of China (WLG) due to increased rice production and increased industrial activity. I don't have any local knowledge of these places, so it was a bit of a guess.

There is a slight increased trend on both sites vs south pole data. While the trend for Barrow  (BRW) is flat.

Now I did deliberately pick these sites because I thought would have the largest increase in emissions. But then I originally expected to see the same trend in Barrow and Tiksi and didn't find it.

I'm no expert on this, so I'm happy for any challenge of these methods.

Great data! I've asked around on Twitter for a couple of scientists about what happened to the Tiksi station. I'll let you guys know if they get back to me

[kassy]

Finding out more about Tiksi would be great.

Sentinel-5 might help but it will be a couple of years before it launches.

When i looked at the arctic stations the big problem is that there are so little stations.
If there were a lot more stations then you could look at other details. IIRC there was a specific error code for measures removed because of some local source made the readings too high.

If there had been more stations with a good spatial distribution it would be interesting to see if  dates with those codes relate to local sea ice break up for example but with the amount of stations we have now that does not work. 

[vox_mundi]

The Moon Controls the Release of Methane in Arctic Ocean
https://phys.org/news/2020-12-moon-methane-arctic-ocean.html

Small pressure changes affect methane release. A recent paper in Nature Communications even implies that the moon has a role to play.

The moon controls one of the most formidable forces in nature—the tides that shape our coastlines. Tides, in turn, significantly affect the intensity of methane emissions from the Arctic Ocean seafloor.

"We noticed that gas accumulations, which are in the sediments within a meter from the seafloor, are vulnerable to even slight pressure changes in the water column. Low tide means less of such hydrostatic pressure and higher intensity of methane release. High tide equals high pressure and lower intensity of the release," says co-author of the paper Andreia Plaza Faverola.

"It is the first time that this observation has been made in the Arctic Ocean. It means that slight pressure changes can release significant amounts of methane.

Plaza Faverola points out that the observations were made by placing a tool called a piezometer in the sediments and leaving it there for four days.

It measured the pressure and temperature of the water inside the pores of the sediment. Hourly changes in the measured pressure and temperature revealed the presence of gas close to the seafloor that ascends and descends as the tides change. The measurements were made in an area of the Arctic Ocean where no methane release has previously been observed but where massive gas hydrate concentrations have been sampled.

"This tells us that gas release from the seafloor is more widespread than we can see using traditional sonar surveys. We saw no bubbles or columns of gas in the water. Gas burps that have a periodicity of several hours won't be identified unless there is a permanent monitoring tool in place, such as the piezometer," says Plaza Faverola

These observations imply that the quantification of present-day gas emissions in the Arctic may be underestimated. High tides, however, seem to influence gas emissions by reducing their height and volume.

"What we found was unexpected and the implications are big. This is a deep-water site. Small changes in pressure can increase the gas emissions but the methane will still stay in the ocean due to the water depth. But what happens in shallower sites? This approach needs to be done in shallow Arctic waters as well, over a longer period. In shallow water, the possibility that methane will reach the atmosphere is greater," says Knies

... The question remains whether sea-level rise due to global warming might partially counterbalance the effect of temperature on submarine methane emissions.



Nabil Sultan et al, Impact of tides and sea-level on deep-sea Arctic methane emissions, Nature Communications (2020).
https://www.nature.com/articles/s41467-020-18899-3

[salbers]

I think we may have liftoff of the CH4 rocket. The annual cycle didn't really have a low point this year.

I think this is an incorrect conclusion

It does seem like an attenuated seasonal minimum and the overall acceleration in the past few years looks somewhat significant? We'll see if this is partially a kink in the curve as in 2015, within the still notable rising trend.

[ArgonneForest]

It is somewhat significant, but I doubt it has mainly to do with Arctic sources. Probably a combination of different sources

[salbers]

It will be interesting to see the growth rate.

The fact that it's not affecting the atmospheric concentrations and most is getting dissolved in the water column leads me to think there will be an increase in methane emissions from the region, but far from the level of a "bomb"

To clarify, there were local increases in atmospheric concentration of around 15x (during 2020). Hopefully this can be better monitored in a spatial and temporal context to see if (or how much) it is growing.

ESAS emissions have been small between 2012-2017 (around 0.6 Tg/yr) if I'm reading this Tohjima et al. paper correctly. The analysis in this paper suggests there had been a regional enhancement of atmospheric CH4 during that period. What is the potential for the 1-2 orders of magnitude of subsequent growth to have a more global impact?

https://www.sciencedirect.com/science/article/pii/S1873965220300803

The ship in the above paper sailed near the ESAS (to its east) though not really in the ESAS itself.

[vox_mundi]

Testing Waters of East Siberian Arctic Ocean Suggests Origin of Elevated Methane Is Reservoir Located In Laptev Sea
https://phys.org/news/2021-03-east-siberian-arctic-ocean-elevated.html



An international team of researchers has found evidence implicating a deep underground reservoir as the source of high levels of methane in the waters of the East Siberian Arctic Ocean. In their paper published in Proceedings of the National Academy of Sciences, the group describes testing three isotopic forms of dissolved methane in the waters.

The work involved first obtaining water samples from regions of the East Siberian Arctic Ocean. Each of the samples then underwent triple-isotope-based fingerprinting. Doing so showed that only a small amount of the methane was coming from shallow microbial sources—the rest was coming from what the team believes is a very large, deep thermogenic reservoir. The researchers also believe the reservoir is located beneath the Laptev Sea; a portion of the East Siberian Arctic Ocean situated north of the eastern part of Russia.

Researchers have found that such releases can sometimes result in pressure building up as the gas makes its way into unstable parts of the ocean floor. And that can lead to seepage or sometimes explosive events as the gas is suddenly released up through the water and to the surface.

Julia Steinbach et al. Source apportionment of methane escaping the subsea permafrost system in the outer Eurasian Arctic Shelf, Proceedings of the National Academy of Sciences (2021).
https://www.pnas.org/content/118/10/e2019672118

... The results consistently point to the presence of an old, predominantly radiocarbon-depleted source of thermogenic origin or a mixture of thermogenic and old microbial sources. The stable isotope source signatures for station 13 fall into a range typical for thermogenic/natural gas origin, whereas the slightly more depleted signal at station 14 indicates additional input from another, potentially microbial origin (Fig. 6A). Both the old radiocarbon signatures (Fig. 6B) and the ebullitive nature of methane at these stations, characterized by abrupt releases and strong spatial gradients in the water column, suggest a deep, advective methane pool as an important contributor to the observed water column methane signal.

... The presence of a thermogenic source pool beneath our study area is consistent with results by Cramer and Franke (24), based on their observations of hydrocarbon concentrations and their δ13C in adsorbed gases in the sediment. The existence of pathways to transport methane from these deep sources to the water column in our study area is also consistent with recent seismic data (25), which show ∼500-m wide gas conduits in the sediment, correlating with a fault zone and cuts through the Neogene succession to the basement.

Further support for a migratory inflow of petroleum hydrocarbons from below is also given by a recent biomarker study in the studied seep area (26): Excess amounts of two molecular markers typical of a petrogenic source have been found in the surface sediment of the studied seep area, with significant differences between the seepage area and the “background areas” without apparent seeps. Taken together, the triple isotopes and these other ancillary data are consistent with a deep thermogenic source of methane.

...Taken together, the triple-isotope data presented here, in combination with other system data and indications from earlier studies, suggest that deep thermogenic reservoirs are key sources of the elevated methane concentrations in the outer Laptev Sea. This finding is essential in several ways: The occurrence of elevated levels of radiocarbon-depleted methane in the water column may be an indication of thawing subsea permafrost in the study area (see also ref. . The triple-isotope fingerprinting suggests, however, that methane may not primarily originate directly from the subsea permafrost; the continuous leakage of an old geological reservoir to the water column suggests the existence of perforations in the subsea permafrost, serving as conduits of deeper methane to gas-charged shallow sediments.

Second, the finding that methane is released from a large pool of preformed methane, as opposed to methane from slow decomposition of thawing subsea permafrost organic matter, suggests that these releases may be more eruptive in nature, which provides a larger potential for abrupt future releases.

.... More triple-isotope data, also temporally resolved, covering a wide range of the inner, mid, and outer shelf in the Laptev, East Siberian, and Chukchi Seas are strongly warranted.

[ArgonneForest]

Two things about this:
1. The research was conducted on the Oden expedition from 2014, so this is not new research per se.
2. Most of the methane was dissolved in the water column since the depths were greater than 50m.

[vox_mundi]

Arctic Methane Release Due to Melting Ice Is Likely to Happen Again
https://phys.org/news/2021-03-arctic-methane-due-ice.html

New research, published on today in Geology, indicates that during the last two global periods of sea-ice melt, the decrease in pressure triggered methane release from buried reserves. Their results demonstrate that as Arctic ice, such as the Greenland ice sheet, melts, similar methane release is likely and should be included in climate models.

Pierre-Antoine Dessandier, a postdoctoral scientist at the Arctic University of Norway, and his co-authors were interested in two periods around 20 thousand years ago (ka), known as the Last Glacial Maximum (LGM), and 130 ka, known as the Eemian deglaciation. Because the Eemian had less ice and was warmer than the LGM, it is more similar to what the Arctic is experiencing today, serving as a good analogue for future climate change.

... The team collected two cores: a 60-meter reference core off the western coast of Svalbard, which they used to date and correlate stratigraphy, and a 22-meter core spanning the LGM and the Eemian deglaciations. The site for the 22-meter core was chosen based on its "pockmark" feature, marking where the gas escaped violently in the past, and massive carbonate rocks that form where methane is still leaking out today.

Carbon isotopes of microscopic shells in the long core revealed multiple episodes of methane release, which geochemists recognize from their distinct spikes in the record. Because methane is still seeping from the sediments, Dessandier needed to to make sure the signal wasn't from modern interference. He compared the shells' carbon isotope values to measurements his colleagues made on carbonate minerals that formed outside the shells, after the foraminifera had died, when methane emission was at its most intense.

The isotopic record showed that as ice melted and pressure on the seafloor lessened, methane was released in violent spurts, slow seeps, or—most likely—a combination of both. By the time the ice disappeared completely, some thousands of years later, methane emissions had stabilized.

Despite modern complications, the team has pinpointed two methane releases associated with ice retreat, like they hypothesize could happen today. The best part for Dessandier was discovering layers of massive bivalves in the cores which, based on modern observations from remotely operated vehicles, can indicate a methane leak. "It was super interesting for us to observe these same sorts of layers at the LGM and the Eemian," he said. "It confirmed what we thought at the beginning, with a methane-rich seafloor allowing this community to develop... We can say that these events are very similar, with similar processes happening during both periods of warming. So this is something to consider for our current warming. It could happen again."

P.-A. Dessandier et al. Ice-sheet melt drove methane emissions in the Arctic during the last two interglacials, Geology (2021).
https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G48580.1/595627/Ice-sheet-melt-drove-methane-emissions-in-the?redirectedFrom=fulltext

[ArgonneForest]

This was also included in the phys.org article:
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Arctic methane release due to melting ice is likely to happen again
by Geological Society of America

Arctic methane release due to melting ice is likely to happen again
Massive lumps of carbonate litter the seafloor where large quantities of methane are leaking from the sediments and rocks below, marking the spot Dessandier and colleagues targeted to drill deep sediment cores. (Scale bar added by GSA.) Credit:G. Panieri.

Beneath the cold, dark depths of the Arctic ocean sit vast reserves of methane. These stores rest in a delicate balance, stable as a solid called methane hydrates, at very specific pressures and temperatures. If that balance gets tipped, the methane can get released into the water above and eventually make its way to the atmosphere. In its gaseous form, methane is one of the most potent greenhouse gases, warming the Earth about 30 times more efficiently than carbon dioxide. Understanding possible sources of atmospheric methane is critical for accurately predicting future climate change.


 
In the Arctic Ocean today, ice sheets exert pressure on the ground below them. That pressure diffuses all the way to the seafloor, controlling the precarious stability in seafloor sediments. But what happens when the ice sheets melt?

New research, published on today in Geology, indicates that during the last two global periods of sea-ice melt, the decrease in pressure triggered methane release from buried reserves. Their results demonstrate that as Arctic ice, such as the Greenland ice sheet, melts, similar methane release is likely and should be included in climate models.

Pierre-Antoine Dessandier, a postdoctoral scientist at the Arctic University of Norway, and his co-authors were interested in two periods around 20 thousand years ago (ka), known as the Last Glacial Maximum (LGM), and 130 ka, known as the Eemian deglaciation. Because the Eemian had less ice and was warmer than the LGM, it is more similar to what the Arctic is experiencing today, serving as a good analogue for future climate change.

"The oldest episode recorded (Eemian) is very important because it was a strong interglacial in the Arctic, with very similar climate characteristics to what is happening today," Dessandier said. "The idea with the Eemian interglacial is to... compare that with what could happen in the future. Seafloor methane emission is important to consider for modeling spatial estimations of future climate."

To track past methane release, Dessandier measured isotopes of carbon (carbon molecules with slightly different compositions) in the shells of tiny ocean-dwellers called foraminifera. Because the foraminifera build their shells using ingredients from the water around them, the carbon signal in the shells reflects the chemistry of the ocean while they were alive. After they die, those shells are preserved in seafloor sediments, slowly building a record spanning tens of thousands of years.


 
To reach that record, Dessandier and the team needed to drill a deep core off the western coast of Svalbard, a Norwegian archipelago in the Arctic Ocean. The team collected two cores: a 60-meter reference core, which they used to date and correlate stratigraphy, and a 22-meter core spanning the LGM and the Eemian deglaciations. The site for the 22-meter core was chosen based on its "pockmark" feature, marking where the gas escaped violently in the past, and massive carbonate rocks that form where methane is still leaking out today.

Carbon isotopes of microscopic shells in the long core revealed multiple episodes of methane release, which geochemists recognize from their distinct spikes in the record. Because methane is still seeping from the sediments, Dessandier needed to to make sure the signal wasn't from modern interference. He compared the shells' carbon isotope values to measurements his colleagues made on carbonate minerals that formed outside the shells, after the foraminifera had died, when methane emission was at its most intense.

The isotopic record showed that as ice melted and pressure on the seafloor lessened, methane was released in violent spurts, slow seeps, or—most likely—a combination of both. By the time the ice disappeared completely, some thousands of years later, methane emissions had stabilized.

How much methane eventually made it to the atmosphere, which is what would contribute to the greenhouse effect, remains uncertain. Part of the problem in quantifying this is the microbial communities that live on the seafloor and in the water, and that use methane to survive.

"For the microbes, it's an oasis. It's fantastic," Dessandier said. "So they grow like crazy, and some species produce methane and others consume it." That activity complicates the core's detailed carbon record. In sediments, a bustling community with lots of methane recycling could overprint the original signal; in the water column, where nutrients may be less plentiful, methane could get gobbled up or transformed into carbon dioxide before it reaches the atmosphere.

[Reginald]

A Massive Methane Reservoir Is Lurking Beneath the Sea

Scientists have found a methane reservoir below the permafrost seabed of the Laptev Sea—a reservoir that could suddenly release large amounts of the potent greenhouse gas.

https://eos.org/articles/a-massive-methane-reservoir-is-lurking-beneath-the-sea

EOS, By Fanni Daniella Szakal 27 April 2021

Methane bubbles regularly reach the surface of the Laptev Sea in the East Siberian Arctic Ocean (ESAO), each of them a small blow to our efforts to mitigate climate change. The source of the methane used to be a mystery, but a joint Swedish-Russian-U.S. investigation recently discovered that an ancient gas reservoir is responsible for the bubbly leaks.

Methane in the Laptev Sea is stored in reservoirs below the sea’s submarine permafrost or in the form of methane hydrates—solid ice-like structures that trap the gas inside. It is also produced by microbes in the thawing permafrost itself. Not all of these sources are created equal: Whereas microbial methane is released in a slow, gradual process, disintegrating hydrates and reservoirs can lead to sudden, eruptive releases.

Methane is escaping as the Laptev’s submarine permafrost is thawed by the relative warmth of overlying seawater. With an even stronger greenhouse effect than carbon dioxide, methane releases into the atmosphere could substantially amplify global warming.

[...]

“The big finding was that we really have something that’s coming out from a deep pool,” said Steinbach. As the permafrost thaws, it opens up new pathways that allow methane to pass through.

According to Gustafsson, this is worrying, as the pool likely contains more methane than is currently in the atmosphere. “There is, unfortunately, a risk that this methane release might increase, so it will eventually have a sizable effect on the climate,” he said.

Source Study: PNAS (March 9): Source apportionment of methane escaping the subsea permafrost system in the outer Eurasian Arctic Shelf

https://www.pnas.org/content/118/10/e2019672118

[jai mitchell]

Interviews with Igor Semiletov

[ArgonneForest]

Yeah, because Semiletov's never overexaggerated before. Oh wait...

[kassy]

So what did he overexaggerate?

[gerontocrat]

I remember 1,2,3 ? years ago doing a lot of digging around about this.

I remember A-team being very caustic about studies that looked at methane release from the sea-bed but at 250+ metres below sea level, whic more or less ensured that most methane gas did not reach the surface. Very large areas of the Arctic ocean near the Siberian coast are less than 50 metres in depth and also much below 10 metres in depth.

I believe it was also shown that highly organic deposits of sediment several hundred metres in depth have been deposited over tens of thousands of years in places along the Siberian coast.

I also remember that apart from melting of clathrates as a source of methane, it is suggested that clathrates may form an impermeable layer over large deposits of free methane formed in those sedimentary deposits, that if punctured (by drilling for deep deposits or weakening through ocean warmth) could lead to explosive release of large amounts of methane.

All this has been poo-hooed by much of the Climate Science Establishment based on a few studies not necessarily in the Arctic Ocean close to the Siberian coast. Like so many things in the Arctic, we still don't have sufficient data.

Nevertheless, its stays in my mind as one of those fat-tailed risks of which there seem to be an ever-increasing number, waiting, to put it colloquially, to bite humanity in the arse.

[ArgonneForest]

This is incorrect as to why it's been treated with skepticism by the mainstream climate community and many Arctic scientists. Various paleo studies, satellite measurements, and field studies from the region have all contributed, including MOSAIC in 2020. Pankratova et. al has done some good work: https://www.researchgate.net/profile/N-Pankratova-3

Also, Paul Overduin and his group have been doing research in the Laptev Sea since at least 2005, and they have not found the same thing as Semiletov et al. So the skepticism is based on more than just a few studies

[morganism]

Has Overduin done any studying of the Laptev Bite, and discerned if that area has higher methane content?

I seem to recall the bathymetry there wasn't very conducive to causing it. I thought there was a seamount west of the area along with a sub canyon?

[oren]

Gero's summary is well put. The jury is still out on the ESAS and methane, not the clathrate kind.

[gerontocrat]

The potential for substantial methane release from the ESAS is a known unknown, and cannot be lightly dismissed, or the paper quoted below would not have been published by PNAS.

Subsea permafrost drilling in the Laptev Sea, in part at the same sites as 30 y ago, has recently confirmed that the subsea permafrost has indeed come near the point of thawing. In addition to mobilization of the carbon/methane stored within the subsea permafrost, its degradation can also lead to the formation of pathways for gaseous methane from underlying reservoirs, allowing further methane release to the overlying water column

Source apportionment of methane escaping the subsea permafrost system in the outer Eurasian Arctic Shelf
Julia Steinbach, Henry Holmstrand,  Kseniia Shcherbakova,  Denis Kosmach, Volker Brüchert, Natalia Shakhova,  Anatoly Salyuk, Célia J. Sapart,  Denis Chernykh,  Riko Noormets, Igor Semiletov, and Örjan Gustafsson

https://tc.copernicus.org/preprints/tc-2021-128/tc-2021-128.pdf

[oren]

The correct link:
https://www.pnas.org/content/118/10/e2019672118

[ArgonneForest]

The potential for substantial methane release from the ESAS is a known unknown, and cannot be lightly dismissed, or the paper quoted below would not have been published by PNAS.

Subsea permafrost drilling in the Laptev Sea, in part at the same sites as 30 y ago, has recently confirmed that the subsea permafrost has indeed come near the point of thawing. In addition to mobilization of the carbon/methane stored within the subsea permafrost, its degradation can also lead to the formation of pathways for gaseous methane from underlying reservoirs, allowing further methane release to the overlying water column

Source apportionment of methane escaping the subsea permafrost system in the outer Eurasian Arctic Shelf
Julia Steinbach, Henry Holmstrand,  Kseniia Shcherbakova,  Denis Kosmach, Volker Brüchert, Natalia Shakhova,  Anatoly Salyuk, Célia J. Sapart,  Denis Chernykh,  Riko Noormets, Igor Semiletov, and Örjan Gustafsson

https://tc.copernicus.org/preprints/tc-2021-128/tc-2021-128.pdf

It's also worth noting this same group has fluctuated between saying it's clathrates, free methane, microbial sources, and now they're saying a geological reservoir? They can't seem to make up their minds.
That being said, I do not dismiss the possibilities. Are they unlikely? Yes. Should contingencies be made to deal with them, geoengineering or otherwise? Absolutely

[ArgonneForest]

I would also add that Shakhova and Semiletov are not free from controversy due to their own actions. This page has a pretty exhaustive history of the ESAS issue: https://www.ecoshock.org/2021/02/arctic-methane-bomb.html

And before you dismiss the claims made by the interviewer, bear in mind that actual Arctic scientists have said such things about S&S. But don't take my word for it, ask experts Sara Sayedi, Ian Brooks, or Ben Abbott about it. Brooks himself has told me about S&S being less than forthcoming on their research

[oren]

The page you cite appears to be biased against S&S and does not present a neutral picture, judging by its tone and content.
In any case, having read the previous S&S paper, it did not appear to be shoddy science. I will make sure to read the new paper as well. The subsea permafrost situation is certainly worrying, but will it result in a large release of methane that reaches the atmosphere is impossible to know at this stage. The "methane scare" McPherson style is irrelevant and should not be mixed into the discussion, the science is what matters.

[ArgonneForest]

Biased doesn't mean it's not true. Like I said, ask the scientists I mentioned about S&S. They're on Twitter. Besides, I have a more authoritative source as well that disputes the subsea permafrost methane argument: https://climatefeedback.org/evaluation/guardian-article-on-arctic-methane-emissions-lacks-important-context-jonathan-watts/

[HapHazard]

> Biased doesn't mean it's not true.

It does make it less likely to be true.

I'm biased against bias, so the previous statement may not be true.

[kassy]

The potential for substantial methane release from the ESAS is a known unknown, and cannot be lightly dismissed, or the paper quoted below would not have been published by PNAS.

Subsea permafrost drilling in the Laptev Sea, in part at the same sites as 30 y ago, has recently confirmed that the subsea permafrost has indeed come near the point of thawing. In addition to mobilization of the carbon/methane stored within the subsea permafrost, its degradation can also lead to the formation of pathways for gaseous methane from underlying reservoirs, allowing further methane release to the overlying water column

Source apportionment of methane escaping the subsea permafrost system in the outer Eurasian Arctic Shelf
Julia Steinbach, Henry Holmstrand,  Kseniia Shcherbakova,  Denis Kosmach, Volker Brüchert, Natalia Shakhova,  Anatoly Salyuk, Célia J. Sapart,  Denis Chernykh,  Riko Noormets, Igor Semiletov, and Örjan Gustafsson

https://tc.copernicus.org/preprints/tc-2021-128/tc-2021-128.pdf

It's also worth noting this same group has fluctuated between saying it's clathrates, free methane, microbial sources, and now they're saying a geological reservoir? They can't seem to make up their minds.
That being said, I do not dismiss the possibilities. Are they unlikely? Yes. Should contingencies be made to deal with them, geoengineering or otherwise? Absolutely

Science takes time. This is from #1212. This is the newest and thus proof there is a deep source:
Of course in the earlier discussions all kinds of theories were not yet ruled out or debated.

Methane stable isotopic composition showed strong vertical and horizontal gradients with source signatures for two seepage areas of δ13C-CH4 = (−42.6 ± 0.5)/(−55.0 ± 0.5) ‰ and δD-CH4 = (−136.8 ± 8.0)/(−158.1 ± 5.5) ‰, suggesting a thermogenic/natural gas source. Increasingly enriched δ13C-CH4 and δD-CH4 at distance from the seeps indicated methane oxidation. The Δ14C-CH4 signal was strongly depleted (i.e., old) near the seeps (−993 ± 19/−1050 ± 89‰). Hence, all three isotope systems are consistent with methane release from an old, deep, and likely thermogenic pool to the outer Laptev Sea.

[ArgonneForest]

So they say...

[Sciguy]

Reviews of global methane budgets have found that Shakova and Semiletov extrapolate the results of the small areas of bubbling that they find over the area of the entire East Siberian Arctic Shelf.  They end up over estimating methane emissions by 4 to 8 times what is actually measured by other groups of scientists. 

https://climatehomes.unibe.ch/~joos/papers/saunois19essddis.pdf

For geological emissions, the most used value has long been 20 Tg CH4yr-1, relying on expert knowledge and  literature  synthesis  proposed  in  a  workshop  reported  in Kvenvolden  et  al.  (2001), the  author  of  this study recognising that this was a first estimation and needs revision. Since then, oceanographic campaigns have  been  organized,  especially  to  sample  bubbling  areas  of  active  seafloor  gas  seep  bubbling.  For instance, Shakhova et al. (2010; 2014) infer 8-17 Tg CH4yr-1emissions just for the Eastern Siberian Arctic Shelf  (ESAS),  based  on  the  extrapolation  of  numerous  but  local  measurements,  and  possibly  related to thawing subseabed permafrost (Shakhova et al., 2015). Because of the highly heterogeneous distribution of dissolved CH4 in coastal regions, where bubbles can most easily reach the atmosphere, extrapolation of in situ  local  measurements  to  the  global  scale  can  be  hazardous  and  lead  to  biased  global  estimates.  Indeed, using  very  precise  and  accurate  continuous  land  shore-based  atmospheric  methane  observations  in  the Arctic region, Berchet et al. (2016) found a range of emissions for ESAS of ~2.5 Tg CH4yr-1(range [0-5]), 4-8  times  lower  than  Shakhova’s  estimates.  Such  a  reduction  in  ESAS  emission  estimate  has  also  been inferred from oceanic observations by Thornton et al. (2016a) with a maximum sea-air CH4 flux of 2.9 Tg CH4yr-1for  this  region. Etiope  et  al.  (2019)  suggested  a  minimum  global  total  submarine  seepage emissions  of  3.9  Tg  CH4yr-1 simply  summing  published  regional  emission  estimates  for  15  areas  for identified  emission  areas  (above  7  Tg  CH4yr-1 when  extrapolated  to  include  non-measured  areas).  These recent results, based on different approaches, suggest that the current estimate of 20 Tg CH4yr-1 is too large and needs revision. Therefore,  as  discussed  in  Section  3.2.2,  we  report  here  a  reduced  range  of  5-10  Tg  CH4yr-1for  marine geological emissions compared to the previous budget, with a mean value of 7 Tg CH4yr-1.

Globally, the estimated methane emissions from the ocean of 7 Tg per year are less than 1/10 of what leaks from the oil and gas industry, 82 Mt per year in 2019.

https://www.iea.org/reports/methane-tracker-2020/methane-from-oil-gas

We estimate there were 82 Mt methane emissions from oil and gas operations in 2019, split in roughly equal parts between the two.

This is why many scientists are more concerned about human activities than the small amounts of methane that come up from bubbling seeps in the Arctic.

[oren]

Obviously human emissions of methane via leakage are a very serious issue. However, they can be stopped more or less at will, while natural emissions cannot. The real question about the ESAS though is not what the emissions are now, but are they growing, at what rate and can this rate accelerate. This bears close watching.

[ArgonneForest]

According to the satellite data, the ESAS emissions are not noticeably increasing

[Linus]

According to the satellite data, the ESAS emissions are not noticeably increasing

Could you please provide a link to this satellite data? Given the controversy surrounding the topic, it would be very interested in seeing quantifiable data on the actual level of emissions from the area. I am quite curious as to the specific monitoring capabilities that are currently in place and the level of accuracy that is to be expected from such a system across different atmospheric conditions.

[gerontocrat]

The most recent satellite sent up is described here..
https://www.bbc.co.uk/news/science-environment-54597764 tells you all about it.

and data maps from https://pulse.ghgsat.com/

BUT..-
- the data is CH4 concentration in ppb- not emissions
- no CH4 shown over any ocean

Then there is this article

"An important new tool to combat climate change is now available. Using data from the Copernicus Sentinel-5P satellite, this new technology makes it possible to track and attribute methane emissions around the world.

https://www.esa.int/Applications/Observing_the_Earth/Copernicus/Sentinel-5P/Mapping_methane_emissions_on_a_global_scale

In the article are maps of various plumes - but nothing from an ocean.

I cannot find a portal with CH4 emissions available on a regular basis. I hope soomeone else can.

[ArgonneForest]

Here you go,  Linus: https://www.ospo.noaa.gov/Products/atmosphere/soundings/iasi/m1/rp/mrm_t1.html

[kassy]

That is not point data though.

Wonder if this could see it:
https://www.ghgsat.com/our-platforms/iris/

But they don´t do free data...

No idea how big the plumes need to be to be detectable

Iris was tasked on 15 September 2020, with measuring a controlled release of methane from a facility in Alberta, Canada. Ground measurements of the controlled release confirmed an emission rate of 260 kgCH4/hr.

That resulted in some dots in the 150 range.

No idea what the ESAS flux is in the area but the real problem is in the source. If it is a deep source it is not just some bubble. It´s gasses coming from some porous system.

[gerontocrat]

That is not point data though.

Wonder if this could see it:
https://www.ghgsat.com/our-platforms/iris/

But they don´t do free data...

No idea how big the plumes need to be to be detectable

Iris was tasked on 15 September 2020, with measuring a controlled release of methane from a facility in Alberta, Canada. Ground measurements of the controlled release confirmed an emission rate of 260 kgCH4/hr.

That resulted in some dots in the 150 range.

No idea what the ESAS flux is in the area but the real problem is in the source. If it is a deep source it is not just some bubble. It´s gasses coming from some porous system.

As of now the ESAS is mostly covered with ice. I suggest that most of any CH4 escaping from the sea bed would therefore likely be trapped underneath the ice and therefore decompose by one of the two methods described below.

When the sea ice cover has gone, and being such shallow water, it is likely that much of the CH4 would escape to the atmosphere. Late summer might mean a warm sea encouraging permafrost melt of the ocean floor thus releasing CH4 from clathrates and perhaps also from deeper free gas reservoirs as the clathrate cap disintegrates.

That's when I will being looking most often at the link provided by ArgonneForest, though it would have to be a big plume to register as increased ppb on the maps.

https://worldoceanreview.com/en/wor-1/ocean-chemistry/climate-change-and-methane-hydrates/

What happens when methane hydrate melts?
Not all the methane that is released from unstable ­methane hydrates ends up in the atmosphere. The greatest portion is likely to be broken down during its rise through the sediments and in the water column. This decomposition is mediated by two biological processes:
-anaerobic oxidation of methane by bacteria and archaea (formerly called archaebacteria) within the sea floor;
-aerobic oxidation of methane by bacteria in the water column.

During anaerobic oxidation of methane in the sediment the microbes use sulphate (SO42–), the salt of sulphuric acid that is present in large quantities in sea water, for the methane decomposition. In this process methane is converted to bicarbonate (HCO3–). If the bicarbonate reacts further with calcium ions (Ca2+) in the seawater, calcium carbonate (CaCO3) precipitates, which remains stored in the sea floor over long periods of time. That would be the ideal situation, because it would make the potent greenhouse gas methane (CH4) harmless. At the same time, hydrogen sulphide (H2S) is produced from the sulphate, which provides energy to chemosynthetic communities, including symbiotic clams and tubeworms. During aerobic oxidation in the water column, however, bacteria break down methane with the help of oxygen (O2). In this process, carbon dioxide is produced, which dissolves in the water. Carbon dioxide contributes to ocean acidification. Furthermore, aerobic oxidation of methane consumes oxygen. The depletion of oxygen in the water column could create or expand oxygen minimum zones in the ocean, which are a threat for fishes and other sensitive organisms. Rough estimates suggest that anaerobic and aerobic oxidation of methane together currently convert around 90 per cent of the methane produced in the sea floor before it can reach the atmosphere. The more slowly methane migrates through the sea floor or through the water column, the more effective the microbes are in converting it.

ps: The article from whence this quote orginates is somewhat old (2010), so the map within it has zero methane hydrates in the ESAS. But the science is good.

pps:- But the article has a warning about the "expansive Arctic shallow-shelf regions"

Methane emissions from the Arctic – a prime focus of future gas hydrate research
In the field of methane emission research today, the Arctic is one of the most important regions worldwide. It is believed that methane occurs there both in the form of gas hydrate in the sea and as free gas trapped in the deep-frozen permafrost. Methane deposits in permafrost and hydrates are considered to be very sensitive in the expansive shallow-shelf regions, because with the relatively low pressures it would only take a small temperature change to release large amounts of methane. In addition, new methane is continuously being produced because the Arctic regions are rich in organic material that is decomposed by microbes in the sediment. The activity of these microbes and thus the biological release rates of methane are also stimulated by increases in temperature. Hence methane emissions in the Arctic have multiple sources. International scientific consortia are now being established involving researchers from various disciplines – chemists, biologists, geologists, geophysicists, meteorologists – which are intensively addressing this problem. No one can yet say with certainty how the methane release in the Arctic will develop with global warming, either in the ocean or on the land. This research is still in its in­fancy.

[ArgonneForest]

That is not point data though.

Wonder if this could see it:
https://www.ghgsat.com/our-platforms/iris/

But they don´t do free data...

No idea how big the plumes need to be to be detectable

Iris was tasked on 15 September 2020, with measuring a controlled release of methane from a facility in Alberta, Canada. Ground measurements of the controlled release confirmed an emission rate of 260 kgCH4/hr.

That resulted in some dots in the 150 range.

No idea what the ESAS flux is in the area but the real problem is in the source. If it is a deep source it is not just some bubble. It´s gasses coming from some porous system.

Regardless, it's the best data we have

[ArgonneForest]

That is not point data though.

Wonder if this could see it:
https://www.ghgsat.com/our-platforms/iris/

But they don´t do free data...

No idea how big the plumes need to be to be detectable

Iris was tasked on 15 September 2020, with measuring a controlled release of methane from a facility in Alberta, Canada. Ground measurements of the controlled release confirmed an emission rate of 260 kgCH4/hr.

That resulted in some dots in the 150 range.

No idea what the ESAS flux is in the area but the real problem is in the source. If it is a deep source it is not just some bubble. It´s gasses coming from some porous system.

As of now the ESAS is mostly covered with ice. I suggest that most of any CH4 escaping from the sea bed would therefore likely be trapped underneath the ice and therefore decompose by one of the two methods described below.

When the sea ice cover has gone, and being such shallow water, it is likely that much of the CH4 would escape to the atmosphere. Late summer might mean a warm sea encouraging permafrost melt of the ocean floor thus releasing CH4 from clathrates and perhaps also from deeper free gas reservoirs as the clathrate cap disintegrates.

It's not necessarily correct that CH4 emissions from the ESAS increase in the summer due to maintenance of the pycnocline: https://www.researchgate.net/publication/350453179_Ocean_stratification_and_sea-ice_cover_in_Arctic_seas_modulate_sea-air_methane_flux_satellite_evidence

[Linus]

Thank you all for the responses. It confirmed what I found frustrating in that we don’t have open source data available where we can see methane emission levels in near real time from satellites in a way that would point us to the source location. If only the investment in scientific research tooling was commensurate with the risk inherent in the subject matter!

[gerontocrat]

It's not necessarily correct that CH4 emissions from the ESAS increase in the summer due to maintenance of the pycnocline: https://www.researchgate.net/publication/350453179_Ocean_stratification_and_sea-ice_cover_in_Arctic_seas_modulate_sea-air_methane_flux_satellite_evidence

Hullo ArgonneForest,

Thanks for the link, my bad for not having read wide enough on the pycnocline. Another paper indicates a big difference between trends in the strength of the halocline between the Eurasian and Amerasian basins. See end of post.

Meanwhile, I think that to some degree we have been at crosspurposes on this discussion. I have always been looking solely at the very shallow seas of the East Siberian, Laptev and Kara shelves.

The first image I attach from the researchgate link is the Barents sea methane emissions anomaly cf deep ocean. The average depth of the area considered is 379 metres. I have always thought that emissions from the sea bed at that depth are likely to be small. With a pressure of 38 bar at the sea floor and warming of the sea very slow and little change between winter and summer sea temperatures at that depth, surely the permafrost and clathrates are likely to be pretty stable.
In addition, a 380 metre water column would destroy most of what CH4 is released from the sea floor.

But as I said, I have been solely looking at the very shallow seas, The bathymetry (second image) shows very large areas of the Eastern Siberian, Laptev and Kara shelves are at or less than 50 metres depth, and a considerable proportion of those shelves at less than 20 metres depth. A pressure of 5 bar or much less at the sea floor implies less stability of the permafrost and clathrates. In addition, the seas are shallow enough for significant heating through insolation in the summer months. Apparently river run-off can also contribute to warmer seas in the summer. But the only data I can find is from a paper in 2011 that said that Summer hydrographic data (1920–2009) show a dramatic warming of the bottom water layer over the eastern Siberian shelf coastal zone (<10 m depth), since the mid-1980s, by 2.1°C
( https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2011JC007218 )

All in all, it seems to me that permafrost and clathrates in those shallow seas is far more vulnerable.

Lastly, the last image attached, from that Researchgate link, suggests to me that the pycnocline does not exist in very shallow seas. Am I right, or am I wrong.
______________________________________________________
https://iopscience.iop.org/article/10.1088/1748-9326/aaec1e
Stability of the arctic halocline: a new indicator of arctic climate change

Abstract
In this study, we propose a new Arctic climate change indicator based on the strength of the Arctic halocline, a porous barrier between the cold and fresh upper ocean and ice and the warm intermediate Atlantic Water of the Arctic Ocean. This indicator provides a measure of the vulnerability of sea ice to upward heat fluxes from the ocean interior, as well as the efficiency of mixing affecting carbon and nutrient exchanges. It utilizes the well-accepted calculation of available potential energy (APE), which integrates anomalies of potential density from the surface downwards through the surface mixed layer to the base of the halocline. Regional APE contrasts are striking and show a strengthening of stratification in the Amerasian Basin (AB) and an overall weakening in the Eurasian Basin (EB). In contrast, Arctic-wide time series of APE is not reflective of these inter-basin contrasts. The use of two time series of APE—AB and EB—as an indicator of Arctic Ocean climate change provides a powerful tool for detecting and monitoring transition of the Arctic Ocean towards a seasonally ice-free Arctic Ocean. This new, straightforward climate indicator can be used to inform both the scientific community and the broader public about changes occurring in the Arctic Ocean interior and their potential impacts on the state of the ice cover, the productivity of marine ecosystems and mid-latitude weather.

[oren]

Indeed the danger zone is the shallow Siberian shelf, for the reasons outlined by Gero, and some kinds of research thrown around are irrelevant to that zone.

[ArgonneForest]

Indeed the danger zone is the shallow Siberian shelf, for the reasons outlined by Gero, and some kinds of research thrown around are irrelevant to that zone.

You don't need to be rude about it, Oren. Are you forgetting the incredibly thick layer of sediment with anaerobic oxidation that oxidizes most of the CH4? How about the fact that it takes time for heat to penetrate down to it?

[ArgonneForest]

It's not necessarily correct that CH4 emissions from the ESAS increase in the summer due to maintenance of the pycnocline: https://www.researchgate.net/publication/350453179_Ocean_stratification_and_sea-ice_cover_in_Arctic_seas_modulate_sea-air_methane_flux_satellite_evidence

Hullo ArgonneForest,

Thanks for the link, my bad for not having read wide enough on the pycnocline. Another paper indicates a big difference between trends in the strength of the halocline between the Eurasian and Amerasian basins. See end of post.

Meanwhile, I think that to some degree we have been at crosspurposes on this discussion. I have always been looking solely at the very shallow seas of the East Siberian, Laptev and Kara shelves.

The first image I attach from the researchgate link is the Barents sea methane emissions anomaly cf deep ocean. The average depth of the area considered is 379 metres. I have always thought that emissions from the sea bed at that depth are likely to be small. With a pressure of 38 bar at the sea floor and warming of the sea very slow and little change between winter and summer sea temperatures at that depth, surely the permafrost and clathrates are likely to be pretty stable.
In addition, a 380 metre water column would destroy most of what CH4 is released from the sea floor.

But as I said, I have been solely looking at the very shallow seas, The bathymetry (second image) shows very large areas of the Eastern Siberian, Laptev and Kara shelves are at or less than 50 metres depth, and a considerable proportion of those shelves at less than 20 metres depth. A pressure of 5 bar or much less at the sea floor implies less stability of the permafrost and clathrates. In addition, the seas are shallow enough for significant heating through insolation in the summer months. Apparently river run-off can also contribute to warmer seas in the summer. But the only data I can find is from a paper in 2011 that said that Summer hydrographic data (1920–2009) show a dramatic warming of the bottom water layer over the eastern Siberian shelf coastal zone (<10 m depth), since the mid-1980s, by 2.1°C
( https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2011JC007218 )

All in all, it seems to me that permafrost and clathrates in those shallow seas is far more vulnerable.

Lastly, the last image attached, from that Researchgate link, suggests to me that the pycnocline does not exist in very shallow seas. Am I right, or am I wrong.
______________________________________________________
https://iopscience.iop.org/article/10.1088/1748-9326/aaec1e
Stability of the arctic halocline: a new indicator of arctic climate change

Abstract
In this study, we propose a new Arctic climate change indicator based on the strength of the Arctic halocline, a porous barrier between the cold and fresh upper ocean and ice and the warm intermediate Atlantic Water of the Arctic Ocean. This indicator provides a measure of the vulnerability of sea ice to upward heat fluxes from the ocean interior, as well as the efficiency of mixing affecting carbon and nutrient exchanges. It utilizes the well-accepted calculation of available potential energy (APE), which integrates anomalies of potential density from the surface downwards through the surface mixed layer to the base of the halocline. Regional APE contrasts are striking and show a strengthening of stratification in the Amerasian Basin (AB) and an overall weakening in the Eurasian Basin (EB). In contrast, Arctic-wide time series of APE is not reflective of these inter-basin contrasts. The use of two time series of APE—AB and EB—as an indicator of Arctic Ocean climate change provides a powerful tool for detecting and monitoring transition of the Arctic Ocean towards a seasonally ice-free Arctic Ocean. This new, straightforward climate indicator can be used to inform both the scientific community and the broader public about changes occurring in the Arctic Ocean interior and their potential impacts on the state of the ice cover, the productivity of marine ecosystems and mid-latitude weather.

The sediment in those shallow areas is incredibly thick, hundreds of meters, and it take considerable time for heat to penetrate down into it: https://www.researchgate.net/publication/339611767_Submarine_Permafrost_in_the_Laptev_Sea

[gerontocrat]

And that is the controversy.

One set of scientists saying it will take many many years for permaforest to be melted at sufficient depth for significant CH4 release,

and on the other hand we have

https://repository.library.noaa.gov/view/noaa/24139
Current rates and mechanisms of subsea permafrost degradation in the East Siberian Arctic Shelf
Authors: Shakhova, N. ; Semiletov, I. P. ; Gustafsson, O. ; Sergienko, V. I. (Valentin Ivanovich) ; Lobkovsky, L. ; Dudarev, O. ; Tumskoy, V. ; Grigoriev, M. ; Mazurov, A. ; Salyuk, A. ; Ananiev, R. ; Koshurnikov, A. ; Kosmach, D. ; Charkin, A. ; Dmitrevsky, N. ; Karnaukh, V. ; Gunar, A. ; Meluzov, A. ; Chernykh, D.

The rates of subsea permafrost degradation and occurrence of gas-migration pathways are key factors controlling the East Siberian Arctic Shelf (ESAS) methane (CH4) emissions, yet these factors still require assessment. It is thought that after inundation, permafrost-degradation rates would decrease over time and submerged thaw-lake taliks would freeze; therefore, no CH4 release would occur for millennia. Here we present results of the first comprehensive scientific re-drilling to show that subsea permafrost in the near-shore zone of the ESAS has a downward movement of the ice-bonded permafrost table of similar to 14 cm year(-1) over the past 31-32 years. Our data reveal polygonal thermokarst patterns on the seafloor and gas-migration associated with submerged taliks, ice scouring and pockmarks. Knowing the rate and mechanisms of subsea permafrost degradation is a prerequisite to meaningful predictions of near-future CH4 release in the Arctic.

So you pays your money and makes yer choice. Me, I have at the back of my mind that as the years go by, no matter what part of the environment is looked at, today's news is usually worse than what it was before.

Only time will tell - and it could be a long wait

[ArgonneForest]

This was from 2017

[kassy]

The new science from #1212 confirms it is a deep source.

This leads us to questions as how much could there be. What is the actual structure. Much of the underground looks more porous then we thought so then you probably have lots of tunnels with gas accumulations. Whenever some escapes at the top this changes pressures in this system leading to more outgassing.

BTW that does not mean that the surface changes in the sea bottom are not problematic but it is a different thing.

[ArgonneForest]

This was for one particular region and does not necessarily extrapolate to other areas. Also, various satellite studies and measurements don't support the idea of increased CH4 emissions coming from the region

[gerontocrat]

My last go at this.

Yes, currently there are not massive CH4 eruptions from the ESAS. If there were, they would have been spotted. But we are discussing the potential, or otherwise, for such events in the future.

Conventional science seems to regard the ESAS as an extremely stable, extremely thick layer of sediment overlaid by a thick very stable permafrost layer. Hence studies that conclude disastrous melt would take perhaps thousand of years.

Shakhova, Semiletov et al dispute this stability. They point to 7 glacial retreats and 7 inundations during the formation of the sediments, current disturbance from increased river run-off and all sorts of other processes above my pay grade. They claim local variation in the structure and vulnerability of these sediments and the overlying permafrost is supported by seismic surveys and drilling.

The analogy that came to mind was how most of old fogies like me used to regard the Greenland and Antarctic ice sheets as great big stable solid lumps of ice. Now we know these ice sheets are full of ice rivers, faults and great stresses and strains that increase their vulnerability to climate change. Perhaps the same applies to these enormous stores of highly organic sediment.

Only a very  small proportion of stored CH4 being released would be one big headache for life on earth.

So I finish where I started - CH4 emissions from the ESAS is a fat-tailed risk that cannot be ignored.

and that's all I'm going to say about that

[ArgonneForest]

And this will be my counter to your last go:

Shakhova et. al have a history of overextrapolating local results to large areas and have been accused by some scientists of restricting their data and potentially fooling around with it. Case in point, the 2014 Oden cruise where many other scientists on the ship, Patrick Crill and Brett Thornton among them, disputed the high CH4 readings that S&S reported.

The fact remains that the sediments are hundreds of meters thick, have efficient AOM, and that it still takes time for heat to penetrate, even with taliks and such things. Also, there is scant evidence of methane hydrates playing a role in the paleo record.

Overduin et. al have done work in the region dating back to at least 2005. They've found degradation of the subsea permsfrost and CH4 emissions occurring, but not nearly at the scale of Shakhova et. al. This is not even including Pankratova et. al who do cruises in the region and have found emissions to be less.

Also, the average emissions of CH4 from the ESAS each year range from 1-4 teragrams each year. Compare this to a total of 570 teragrams emitted globally each year. This would mean that emissions from that region would have to increase 150-600 fold to be on par with global emissions. That's a huge scale that would have to happen in a really short period of time.
I'll end with my three question maxim: 1. Is this possible? Certainly 2. Is it likely? Probably not 3. Should contingency plans be drawn up to deal with such an eventuality?Absolutely