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Neven

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Re: Arctic Methane Release
« Reply #400 on: October 09, 2017, 10:06:20 AM »
Yes, Gavin Schmidt was bought off with Hansen's job. A combination of persuasions were required with Archer.

Don't. This forum wouldn't even be here, if it weren't for people like Gavin Schmidt.
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Don't confuse me with him

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Thomas Barlow

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Re: Arctic Methane Release
« Reply #401 on: October 09, 2017, 06:21:37 PM »
I still doubt that subsea permafrost degradation causing increases in the release of methane will be a net positive with regards to general warming of the planet. This is what I believe notwithstanding the research you have posted which I have not read.
Yes, after 5 or 6 studies I posted here, you are welcome to stick with your "beliefs", as you call them.

Quote
I admit I am a scientific lightweight. I will assume that the research you reference is accurate. The researchers have identified a process where sub-sea methane releases can trigger an explosive growth in organisms which will increase carbon uptake. This may even mean that there can be specific time periods and locations where this results in a net reduction in atmospheric CO2e. It is one thing to scientifically demonstrate a process and then argue that this natural process should be assumed to absolutely operate continuously on a global scale. There are other things to consider such as growing seasons which will reduce the growth and carbon uptake of these organisms. It is quite incorrect to suggest that methane releases from areas of the sea floor have a similar seasonal periodicity. Once the permafrost in the ESS and Laptev has degraded and begun to release methane, this release occurs year round, no pause during the dark Arctic winter.

No, it does not happen year-round.
That is the whole point of the 'ice cap' in this reguard. It caps the methane long enough for it to degrade in the ocean. Where there is no ice, and methane is released from the ocean floor, the methane is released immediately to the atmosphere, but the accompanying explosion of algae and life will sequester CO2 at a rate that is hundreds of times more than the warming effect of the methane being released into the atmosphere. It is like finding out the Earth is round, and then saying, "Yea, of course it is. It's a no-brainer. How come I never thought of that before? The evidence is everywhere. Kindof self-evident really" But people get stuck in their former paradigms, they can't shift, especially if it does't come from them, or someone they admire, or are in their clique. This is science. It is hard-core, and does not involve "belief" as you put it. It involves discussion of scientific findings, and evolving with those findings.

Humans may be screwed, but one thing that is unlikely to be the worst factor is methane release from arctic or tundra. You need to go back and read all my posts on this.


A-Team

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Re: Arctic Methane Release
« Reply #402 on: October 09, 2017, 06:28:23 PM »
Rightly or wrongly, the decision was made early on to settle on the 2º
C-from-CO2-by-2100 narrative. I would say wrongly. Wadhams made a strong case for disappearing Arctic Ocean ice by 2020 but that did not fit the story line. Methane release from the ESAS researched so carefully by Semiletov and Shakhova was equally unwelcome. And the magnitude of cow-belched methane (even grass-fed) remains completely unmentionable.

https://cbmjournal.springeropen.com/articles/10.1186/s13021-017-0084-y

So here we are today with our heads still deep in the CO2 saturated sand. It's not going to work, kicking that particular can down the road. We need to lay out the real risks, a realistic timeline for them, and proportionate measures that need to be taken now, be they ever so inconvenient.

As time permits, I'll see about popularizing the S&S article. This one is largely about the largely unfamiliar evolution of submerged frozen land and whether built-up methane is safely trapped underneath or finding routes up and out. Or rather, they're explaining why the latter is happening in terms of cryo-geology widespread off Siberia, contrary to assumptions of mid-America modeling campaigns.

Methane itself is not so difficult but its politicization within certain segments of the scientific community has gotten very ugly: methane is a threat to the paradigm, therefore its threat to the climate has to be belittled. That's a poor way to go though on climate risk assessment.

The first thing I do with a methane article is skim through to what the authors take for CO2 equivalency (by itself often belittled). If it's 20, that's rubbish, I don't read further. Time is better spent on straight science than reading another biased blast from yet another paradigm defender.

Not wanting methane is a very different thing from not getting methane.
« Last Edit: October 10, 2017, 12:03:32 AM by A-Team »

Thomas Barlow

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Re: Arctic Methane Release
« Reply #403 on: October 09, 2017, 06:31:07 PM »
Semiletov and Shakhova were not 'hinting' at anything.  They were telling you point blank.

The area of hotspots of methane are spreading, now encompassing a full 10% of the 2 million sq km of the ESAS. Which is 200,000 sq km.
Not only is the area of release spreading, the rate and volume of release is increasing, and they expect it to increase exponentially 3-5 orders of magnitude.
That there is no way to shut this off, short of sea level dropping and exposing the shelves to temperatures capable of refreezing the permafrost.  We know that isn't going to happen.
That the methane will continue to release until there is no more to release, and that just 1% of the available methane will be enough to cause catastrophic climate change.
The interview with Semiletov and Shakhova was published 24 June 2017.  their paper,  Current rates and mechanisms of subsea permafrost degradation in the East Siberian Arctic Shelf, was published 22 June 2017.

You want to challenge their research, I've provided links.   

You still don't understand the studies I posted. Please explain them to me - even if you don't 'believe' them, so that I am sure you actually understand them. Otherwise there is no point discussing this with you, since you are technically discussing a completely different topic, focused on the amount of methane that could get released. That has nothing to do with the core finding of the studies I posted. You don't understand the studies.
 Shakova  et al do not in any way address the research I have been posting ( 5 or 6 studies, I lost count). They are ONLY talking about methane release. You are just name-dropping because you haven't read (or do not understand) the research I posted.
Please explain to me what you think the studies I posted are saying. I don't think you read them, because your answers do not address the core points at all.
« Last Edit: October 09, 2017, 06:38:06 PM by Thomas Barlow »

Capt Kiwi

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Re: Arctic Methane Release
« Reply #404 on: October 09, 2017, 07:57:36 PM »
Rightly or wrongly, the decision was made early on to settle on the CO2-in-2100 narrative. I would say wrongly. Wadhams made a strong case for disappearing Arctic Ocean ice by 2020 but that did not fit the story line. Methane release from the ESAS researched so carefully by Semiletov and Shakhova was equally unwelcome. And the magnitude of cow-belched methane (even grass-fed) remains completely unmentionable.

Wow! Hearing that from somebody of the caliber of A- Team is a little scary!

gerontocrat

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Re: Arctic Methane Release
« Reply #405 on: October 09, 2017, 10:13:42 PM »
From what I read it would seem that when local conditions favour slow release of ch4 this allows the ch4 bubbles to completely dissolve in the ocean thus encouraging algal blooms.

The studies by Semiltov and Shakhova seem to me to point to the possibility of rapid release of ch4 in the less than 50 m depth of large parts of the ESS as the permafrost cap over the hydrates weakens,  thus allowing much of the ch4 to be released as gas into the atmosphere. Shallow seas warm up quickly to sufficient depth to attack the permafrost.

Not only hydrates but there are also perhaps large amounts of free ch4 gas at greater depth formed from the decay over many thousands of years of carbon rich soil confined under pressure would be released as the hydrate layer thinned and broke. Rather like the classic geology of oil and gas under pressure trapped under a salt dome. Puncture the cap and whoosh! a gusher.

Different geomorphology and ocean depth and temperatures produce different results. The logic is too persuasive for comfort, especially if the Arctic ocean in the ESAS continues to warm.
« Last Edit: October 09, 2017, 10:19:44 PM by gerontocrat »
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wili

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Re: Arctic Methane Release
« Reply #406 on: October 09, 2017, 11:19:42 PM »
Thanks for the clarity, g.
"A force de chercher de bonnes raisons, on en trouve; on les dit; et après on y tient, non pas tant parce qu'elles sont bonnes que pour ne pas se démentir." Choderlos de Laclos "You struggle to come up with some valid reasons, then cling to them, not because they're good, but just to not back down."

oren

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Re: Arctic Methane Release
« Reply #407 on: October 10, 2017, 01:04:05 PM »
Two idiot questions pertaining to all of the above:
TB - if the research shows that methane release causes explosions of algae blooms, thus saving us. Consider that S&S have discovered numerous methane hot spots above the ESAS, so ARE there explosions of algae blooms in the ESS? I mean, here's a real life test case, from the little I understand of the research.
S&S or whoever knows - if the methane has been building over a million years, over quite a few glacials and interglacials, what has changed recently to cause the release? Is AGW in its current level enough to cause such a profound change? Or is it the loss of ESS summer ice cover? In short, why now?

Shared Humanity

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Re: Arctic Methane Release
« Reply #408 on: October 10, 2017, 05:09:15 PM »
You need to go back and read all my posts on this.

You'll need to forgive me since I won't.

Thomas Barlow

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Re: Arctic Methane Release
« Reply #409 on: October 10, 2017, 05:19:51 PM »
From what I read it would seem that when local conditions favour slow release of ch4 this allows the ch4 bubbles to completely dissolve in the ocean thus encouraging algal blooms.
Not only hydrates but there are also perhaps large amounts of free ch4 gas at greater depth formed from the decay over many thousands of years of carbon rich soil confined under pressure would be released as the hydrate layer thinned and broke. Rather like the classic geology of oil and gas under pressure trapped under a salt dome. Puncture the cap and whoosh! a gusher.
Yes, some big explosions into the atmo., but that is not the main issue, and they will cause MASSIVE algae blooms. The CO2 sequestration will be huge. It is nature's carbon-credit, just like businesses are encouraged to do.
The biological activity would be much larger than when just bubbles. It's a no-brainer. You all forget that the reason life evolved on Earth (in the ocean) is because it is the IDEAL place for an explosion of biological activity and diversity. It's what the ocean does. Linear thinking humans cannot really conceive of the biological powerhouse that is the ocean.
So when a mass of methane is released the activity will be bigger and last longer.
Quote
Different geomorphology and ocean depth and temperatures produce different results. The logic is too persuasive for comfort, especially if the Arctic ocean in the ESAS continues to warm.
Oh, it's not going to be good, but not a linear straight line effect without any nuance or gray areas.
And of course many other factors of climate-change make it almost a moot point, but there is a known balancing effect that was not known a few years ago, is now obvious (6 or 7 studies - science-denial and personal opinion is fast becoming irrelevant on this)
« Last Edit: October 10, 2017, 05:26:35 PM by Thomas Barlow »

Thomas Barlow

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Re: Arctic Methane Release
« Reply #410 on: October 10, 2017, 05:32:15 PM »
Two idiot questions pertaining to all of the above:
TB - if the research shows that methane release causes explosions of algae blooms, thus saving us.
This balancing effect of methane to CO2 sequestration is not going to save us. It's just science, and science is always unfolding. It is somewhat good news in terms of massive global warming of over 6 degrees C over 10-20 years, which a linear, unbalanced, mass methane release would cause, and you'll all be dead at about 4 degrees. It provides a somewhat better scenario than that. Only some.
Quote
Consider that S&S have discovered numerous methane hot spots above the ESAS, so ARE there explosions of algae blooms in the ESS? I mean, here's a real life test case, from the little I understand of the research.
Yes, you can see them on satellite photos in shallow Arctic seas whenever there is a open water and a clear sky
Quote
Is AGW in its current level enough to cause such a profound change? Or is it the loss of ESS summer ice cover?
Both.

Thomas Barlow

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Re: Arctic Methane Release
« Reply #411 on: October 10, 2017, 05:35:28 PM »
You need to go back and read all my posts on this.

You'll need to forgive me since I won't.
OK, then please stay uninformed.

Shared Humanity

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Re: Arctic Methane Release
« Reply #412 on: October 10, 2017, 07:08:04 PM »
OK...I decided to read the most recent link provided that takes me to research showing how CO2 uptake in areas where methane seeps are active overwhelms the warming effects of methane increases in the atmosphere which thus means that underwater methane seeps act as a powerful negative feedback. The more underwater methane released, the cooler the planet will be.

The link took me to an article as opposed to the research which is fortunate in that I would have struggled to understand it anyway. I have read the article and included some quotes from the researchers regarding their conclusions.

"If what we observed near Svalbard occurs more broadly at similar locations around the world, it could mean that methane seeps have a net cooling effect on climate, not a warming effect as we previously thought," said USGS biogeochemist John Pohlman, who is the paper's lead author. "We are looking forward to testing the hypothesis that shallow-water methane seeps are net greenhouse gas sinks in other locations."

It would appear that the lead author does not consider methane seeps as the planets refrigerator as a "no brainer".

The article includes this sentence...

"Photosynthetic algae (marine phytoplankton) appeared to be more active in the near-surface waters overlying the seafloor methane seeps, a phenomenon that would explain why so much carbon dioxide was being absorbed."

"Appeared" hardly seems to be a term used in rigorous research. What gave them that appearance?

I would also like to point out the water depths where these readings were taken...

"Analysis of the data confirmed that methane was entering the atmosphere above the shallowest (water depth of 260-295 feet or 80-90 meters) Svalbard margin seeps. "

It should be noted that in the exhaustive research regarding methane seeps in the ESS and Laptev, much of the sea floor is less than 20 meters deep and almost all of this methane rich shelf is less than 50 meters deep.

Even the author of this research does not consider it to be the final definitive research on the topic. I remain unconvinced that sub-sea methane seeps and the sub-sea permafrost degradation being documented in the ESS are not a significant risk.




gerontocrat

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Re: Arctic Methane Release
« Reply #413 on: October 10, 2017, 07:12:00 PM »
Hullo Oren.
Idiot qu.1. Not the faintest idea. Vague memory of a study on seas near Svalbard ?
Idiot qu. 2. Found a paper - them Russkies again. Suggests cause of quick increase in co2 from 190  to 270 ppm that happened soon after last inter glacial may have been triggered by permafrost exposed as ice sheet retreated. Hence lots of interest from scientists looking at NOW?

Found a paper that said most ch4 in the ESAS is Pleistocene. Also in other papers talk about greatly increased flow in Siberian rivers dumping big amounts from peatlands in the ESAS during the Holocene and accelerating now.
Northern sea route opens. Insolation. Shallow sea warms. Permafrost on sea floor melts. Many many gt of ch4 escapes. Climate stuffed.

Ps . Doing this on mobile so can't give you links. Your turn to get a headache first finding and then wading thru very very scientific abstracts.
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AbruptSLR

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Re: Arctic Methane Release
« Reply #414 on: October 10, 2017, 07:26:52 PM »
S&S or whoever knows - if the methane has been building over a million years, over quite a few glacials and interglacials, what has changed recently to cause the release? Is AGW in its current level enough to cause such a profound change? Or is it the loss of ESS summer ice cover? In short, why now?

At the risk of oversimplifying a complex issue, I believe that the primary answer to your question of 'why now?' is:
1. Over the past million years only two interglacial periods (MIS 11 & 5) have a reasonable combination of ocean temperature and sea level to both inundate and then begin to degrade the submerged permafrost in the ESAS (see the blue curve in the first attached image).
 2. However, during both the MIS 11-Holsteinian, and the MIS 5-Eemian, eras the duration of conditions equal or above modern conditions was less than 5,000 years which is short compared to the Holocene where modern condition have existed for almost 12,000 years (see the second attached image).
3. 5,000 years is too short of a period for the heat of the sea water inundating the ESAS to adequately degrade the submerged permafrost to release significant quantities of methane, while 12,000 years is very near to the duration necessary conditions to begin to release the least stable of the submerged methane regions.
4.  The rapid loss of Arctic sea ice extent has exposed the portions of the ESAS in less than 50m of water depth to storm wave mixing that has conveyed relatively warm sea water to the shallow regions of the ESAS which in certain susceptible regions (such as regions with high erosion of sediment overburden above the methane bearing layers, say due to currents and wave action during inundation 12,000 years ago) to cross their thresholds for releasing methane (as observed by S&S in localized areas).

Finally, I note that during both the MIS 11 and MIS 5 eras it is likely that the WAIS collapsed; which has not yet happen in modern times.  If/when the WAIS collapses before 2100, this event would both drive relatively warm Pacific waters into the Arctic Basin and would increase Arctic Amplification; both of which would significantly increase the risk of meaningful methane emissions from the ESAS before 2100.
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Shared Humanity

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Re: Arctic Methane Release
« Reply #415 on: October 10, 2017, 07:27:05 PM »
I thought I would point out that the primary mission of this research vessel from which this study was performed is to assess the viability of gas hydrates as an energy source.

I leave it to the reader to decide if this is relevant or whether it might suggest a research bias.

AbruptSLR

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Re: Arctic Methane Release
« Reply #416 on: October 10, 2017, 08:00:51 PM »
I have read the article and included some quotes from the researchers regarding their conclusions.

"If what we observed near Svalbard occurs more broadly at similar locations around the world, it could mean that methane seeps have a net cooling effect on climate, not a warming effect as we previously thought," said USGS biogeochemist John Pohlman, who is the paper's lead author. "We are looking forward to testing the hypothesis that shallow-water methane seeps are net greenhouse gas sinks in other locations."

It would appear that the lead author does not consider methane seeps as the planets refrigerator as a "no brainer".

The article includes this sentence...

"Photosynthetic algae (marine phytoplankton) appeared to be more active in the near-surface waters overlying the seafloor methane seeps, a phenomenon that would explain why so much carbon dioxide was being absorbed."

"Appeared" hardly seems to be a term used in rigorous research. What gave them that appearance?

I would also like to point out the water depths where these readings were taken...

"Analysis of the data confirmed that methane was entering the atmosphere above the shallowest (water depth of 260-295 feet or 80-90 meters) Svalbard margin seeps. "

It should be noted that in the exhaustive research regarding methane seeps in the ESS and Laptev, much of the sea floor is less than 20 meters deep and almost all of this methane rich shelf is less than 50 meters deep.

Even the author of this research does not consider it to be the final definitive research on the topic. I remain unconvinced that sub-sea methane seeps and the sub-sea permafrost degradation being documented in the ESS are not a significant risk.

These topics are often complex, and it can be difficult to say what the net feedback will be until models are better calibrated to account for the possible positive feedback cited in the linked article and associated reference for algae blooms in the Arctic Ocean (I noted that methane fed algae would like contribute to this positive feedback thus at least partially offsetting any negative feedbacks associated with the CO₂ absorbed by the algae growth):

Title: "Blooming Algae Could Accelerate Arctic Warming"

http://www.climatecentral.org/news/algae-accelerate-arctic-warming-18929

Extract: "There’s no question that algae blooms are on the increase as Arctic ice thins. Scientists have generally believed that more algae — more specifically, the type known as phytoplankton — would be good for the climate, since they thrive on CO2 while alive, then carry the carbon they’ve absorbed down to the sea bottom when they die. Some experts have even suggested that fertilizing the oceans to encourage algal growth would be one way to counteract global warming.

But Park and his co-authors point out that thicker layers of algae on the sea surface would prevent sunlight from penetrating deeper into the water.

“More heat is trapped in the upper layers of the ocean, where it can be easily released back into the atmosphere,” Park said. He and his team reached this conclusion by marrying computer models of how ocean ecosystems behave to models that simulate the climate. Then they ramped up levels of CO2 to see how the algae would respond to the resulting warming, the extra carbon dioxide itself, and changes in sea ice.

See also:

Jong-Yeon Park et al (2015), "Amplified Arctic warming by phytoplankton under greenhouse warming", PNAS, vol. 112 no. 19,  5921–5926, doi: 10.1073/pnas.1416884112

http://www.pnas.org/content/112/19/5921

Abstract: "Phytoplankton have attracted increasing attention in climate science due to their impacts on climate systems. A new generation of climate models can now provide estimates of future climate change, considering the biological feedbacks through the development of the coupled physical–ecosystem model. Here we present the geophysical impact of phytoplankton, which is often overlooked in future climate projections. A suite of future warming experiments using a fully coupled ocean−atmosphere model that interacts with a marine ecosystem model reveals that the future phytoplankton change influenced by greenhouse warming can amplify Arctic surface warming considerably. The warming-induced sea ice melting and the corresponding increase in shortwave radiation penetrating into the ocean both result in a longer phytoplankton growing season in the Arctic. In turn, the increase in Arctic phytoplankton warms the ocean surface layer through direct biological heating, triggering additional positive feedbacks in the Arctic, and consequently intensifying the Arctic warming further. Our results establish the presence of marine phytoplankton as an important potential driver of the future Arctic climate changes."
« Last Edit: October 10, 2017, 08:55:26 PM by AbruptSLR »
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Re: Arctic Methane Release
« Reply #417 on: October 10, 2017, 08:27:35 PM »
Thanks ASLR.  The system is so complex.

gerontocrat

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Re: Arctic Methane Release
« Reply #418 on: October 10, 2017, 09:18:33 PM »
From previous post by shared humanity the USGS study refers to seepage (slow release?) at 80-90 meters depth near Svalbard. The Russian study talks about rapid release at  max of 50 m depth in the ESAS.

Different local conditions produce different results ?
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longwalks1

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Re: Arctic Methane Release
« Reply #419 on: October 10, 2017, 09:35:47 PM »
I do hope to see more of the Norsk womyn (and men) and any others from CAGE on EGU videos again about Svalbard. To hear the evolution of young field scientists after a couple years in a complex developing fields is instructive and fascinating.  From the 11:00 minute on is about deep seepage creating a biological oasis. 

   It was previously posted. 

When I moved back south, I shredded many videos from before crossing border and did not back the big ones onto the cloud.  Off topic slightly, but I miss the video from a Pleistocence presentation where he goes into the data he has assembled and graph where he makes the case that a methane burp at the very beginning of agriculture can be shown and he pinpoints cattle and rice.  If anyone has it off the top of their head, I would like to review it.  Several years old.

This is the place to be looking at conflicting views in the science and scientists.  From the Ruppell paper I get that the ins and outs of the methane cycle has significant degrees of uncertainty, and they do their best.  And also that presently the largest methane emission by far today is cattle and rice production. 

From Semiltov and Shakhova etc. we now have a several year survey showing an increase and raw data to be applied to finding and making models  of the present day and models for the future. 
Current rates and mechanisms of subsea permafrost degradation in the East Siberian Arctic Shelf 
DOI: 10.1038/ncomms15872  previously posted here.

The CAGE survey around Svalvard is another example of raw data coming out, which is not at the caprice U.S. funding so much.  Yeah.

This is an evolving situation in the science and in the field.  I am reminded about the studies about winter pemafrost methane emissions and how they found a huge difference between wet and dry decaying permafrost emissions. 
Cold season emissions dominate the Arctic tundra methane budget     doi/10.1073/pnas.1516017113           That is not so relevant for the previous discussion, it is just an example of how the studies on methane and methane emissions from the arctic is ongoing. 

Can we agree to disagree amicably.  I have not read the new stuff yet.  If anyone who has read it can post their opinions about differences that might occur with light versus dark with the photosynthesis portions;  what are the rate limiting presursors (sulfur compounds?) and what effects  these pathways would have on ph I would deeply appreciate.

oren

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Re: Arctic Methane Release
« Reply #420 on: October 11, 2017, 12:28:01 AM »
At the risk of oversimplifying a complex issue
ASLR - thank you for your very good explanation. Simplification is what I was looking for, as sometimes understanding is lost among the details. And that you for all the other responses to my questions.
I too believe that the research in Svalbard is not necessarily applicable to the ESS, due to different conditions (rate of seepage and depth of seafloor), but hopefully the research will be extended to that area as well at some point.
TB - I was looking to see whether algae blooms have empirically appeared in greater numbers in areas of methane seeps, compared to areas with no seeps. If they appear over the whole arctic, then maybe they are not connected to methane.

Thomas Barlow

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Re: Arctic Methane Release
« Reply #421 on: October 11, 2017, 03:52:08 PM »
The reason I said people need to go back a few pages on this topic area and read my posts is because it is not just one study.  Focusing on one study is not enough. To me, in science, several studies, on a similar effect, showing similar results (eg. biological activity is a net cooling effect) is pointing to a growing body of evidence. Taking one study on its own and thinking that is how you are going to analyze the topic is not being informed on the topic. That's why, a few pages back here, I said that the first study I posted (for which I was given the derogatory charge or 'hopium' and "that study was debunked' with no citation to said debunking), I said that "it's just one study, the juries out on this one". But since then, I have posted several studies on similar or related effects, some published recently, and it is becoming a body of research. Just like you wouldn't pick apart one study on climate-change research (eg. saying "appeared" is not a scientific term), to ignore or trash all the others, is not a valid approach here. The overall effect is a growing body of research and needs to be taken as a whole. Every time methane is released (in small or large quantities) there will be a massive CO2 sequestration that causes a cooling effect that far outweighs the warming effect of methane released into the atmosphere.
And, no, I doubt any warming effect of algae or biological activity on the ocean amounts to much compared to the overall cooling balance. But let me know when someone does a full published study on it, and that will be a start.

However, the net cooling effect (that I think is one reason the Arctic ice is not disappearing super fast - just somewhat fast) will not be enough to reverse Arctic meltdown. Other problems, such as pollution and plastic in the Arctic ocean (because it seems to gather plastic from elsewhere), warming N. Atlantic which seeps under the Arctic, soot from more and more wildfires landing on the ice, and general global warming, mean that the net cooling effect may not be enough to slow the Arctic Ice melt. It may mitigate (not stop) global human disaster in general, giving time for a reprieve, but the state of the other oceans is so bad now (acidic, fished out, ecosystem out of balance - sure glad I've been vegetarian for 35 years), it's hard to see how dying oceans are not in our future. I hope nature has more surprises for us, because with the leaders we have in power, we are not going to do it.
This net cooling effect, will be a feature of the melting Arctic, and could slow some warming, but I doubt would reverse anything, just make the demise less abrupt.
« Last Edit: October 11, 2017, 06:35:56 PM by Thomas Barlow »

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Re: Arctic Methane Release
« Reply #422 on: October 11, 2017, 06:13:03 PM »
TB - I was looking to see whether algae blooms have empirically appeared in greater numbers in areas of methane seeps, compared to areas with no seeps. If they appear over the whole arctic, then maybe they are not connected to methane.
For methane, just in shallow peripheral seas at this point, I would think.
There's too much ice over the arctic ocean most of the time, and most methane would likely just be absorbed by other processes before it is emitted to atmosphere, is my understanding. So, effect can only be observed in shallow seas (ESS, Beaufort. etc.), because wider Arctic is covered, and we know methane would mostly be absorbed under ice (or even if there is some open water, it wouldn't be significant enough). The bottom of the Arctic Ocean emitting methane is not really the concern right now, but if it does emit in large quantities, and there is a large swathe of open water, I think you will sea the blooms. We are maybe years from that though.
I think it is mostly in the shallow seas that Shakova and Wadhams and others are talking about (and the tundra, which has other possible mitigating factors to mass methane release)
But, yes, there are many other things that cause algae blooms, as you know more about than me (river effluence, Ekman Flux, for example). It's not definitive, I was just suggesting that if there are methane releases going on (which we know there are), it would show up as algae blooms in the shallow seas where those releases are. To try to delineate in satellite photos which are river effluence, Ekman Effect, etc., and which are methane effects, will be more difficult, but I doubt anyone can point to an algae bloom in shallow seas yet (away from rivers) and definitively say that "methane did not have an impact".
Greenland will be interesting because there is so much iron and other minerals in the surface ice that when it melts, it will cause the same effects around Greenland, maybe not obvious algae blooms but other ecosystem activity. I've been thinking this for years now, so when studies showed it with methane (nutrient bursts), then it is a no-brainer to me. Like someone said "The Earth is round", and I say, "Wow, yes, of course it is. How come I never thought of that before?" Everyone is going to have to modify their viewpoint on this, including Wadhams and Shakova, etc.
(but like I say, it is likely just a mitigating factor, not a reversal of global warming or ice receding over time).
« Last Edit: October 11, 2017, 06:46:10 PM by Thomas Barlow »

Capt Kiwi

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Re: Arctic Methane Release
« Reply #423 on: October 11, 2017, 07:45:51 PM »
I can see how frustrated you are Thomas, and I can see your point of view.
I’m sure you could also understand however, the paradox of your argument, and that the idea is simply counter intuitive.
We all agree that the climate and environmental mess we are in is caused primarily by the excessive release of carbon and other gh gases, causing ocean warming and acidification. Yet... you are saying the way to fix or mitigate this is to release more carbon and methane into the ocean.
I’m not debating the science, just pointing at the very difficult challenge anybody would have in accepting this concept, especially when at least some of it is generated from research done to support commercial methane mining in that area.

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Re: Arctic Methane Release
« Reply #424 on: October 11, 2017, 09:43:15 PM »
From 2015:

The East Siberian Arctic Shelf: towards further assessment of permafrost-related methane fluxes and role of sea ice
Quote
Our data show that at a shallow water depth, approximately 67–72% of CH4 remains in the bubbles when the bubbles reach the sea surface.

Dissolved CH4 in the outer ESAS requires 300–1000 days to be oxidized in the water column because CH4 oxidation rates are very low (mean±1 s.d.: 0.0988±0.1343 nM d−1, p=0.95, n=328). During this time, some of the aqueous CH4 inventory is likely to be released to the atmosphere during storms [10]. The remaining dissolved CH4, captured beneath the sea ice in winter, can spread further from the ESAS via currents (figure 4), and some can escape to the atmosphere through leads and breaks in the ice [34].

Sea ice serves as a natural physical barrier that restricts CH4 emissions from the ESAS during the ice-covered period. Because the temperature in the Arctic has increased at twice the rate as in the rest of the globe, and the region is expected to increase an additional 8°C (14°F) in the twenty-first century [3], longer periods of open water and shorter ice-covered periods [35,36] are occurring. Increasing periods of open water implies an increasing number of storm events, when wind speed increases to 15 m s−1 or more and the boundary between sea surface and air increases many times due to deep water mixing. Such events have the potential to rapidly ventilate bubble-transported and dissolved CH4 from the water column, producing high emission rates to the atmosphere. Because more than 75% of the total ESAS area is less than 50 m in depth, the water column provides bubbles with a very short conduit to the atmosphere. Storms enable more CH4 release because they destroy shallow water stratification and increase the boundary between sea surface and air, thus increasing gas exchange across phase boundaries. As a result, bubble-mediated, storm-induced CH4 ‘pulses’ force a greater fraction of CH4 to bypass aqueous microbial filters and reach the atmosphere [10].

In addition, about 10% of the ESAS remains open water in winter due to formation of flaw polynyas. It was shown that flaw polynyas provide pathways for CH4 escape to the atmosphere during the arctic winter [37]. Areas of flaw polynyas in the ESAS increased dramatically (by up to five times) during the last decades, and now exceed the total area of the Siberian wetlands (electronic supplementary material, figure S5). This implies that the ESAS remains an active source of CH4 to the atmosphere year-round.
link



 
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Re: Arctic Methane Release
« Reply #425 on: October 12, 2017, 12:03:20 AM »
Methane cycling in Arctic shelf water and its relationship with phytoplankton biomass and DMSP
Quote
Methane in situ production occurs frequently in the oxygenated upper ocean. A principal pathway by which methane can be formed is methylotrophic methanogenesis, while an important methylated substrate is DMSP (dimethylsulfoniopropionate) produced by marine phytoplankton. Here we report on an in situ methane production/consumption cycle during a summer phytoplankton bloom and a potential link to DMSP concentration in Storfjorden (Svalbard Archipelago) – a polar shelf region.
We propose that methane in situ production occurs during the summer phytoplankton bloom. The concentration of methane increases up to a certain threshold value, above which methane consumption begins. A methane production-removal cycle is established, which is reflected in the varying methane concentrations and δ13CCH4 values. DMSP and methane are inversely correlated suggesting that DMSP could be a potential substrate for the methylotrophic methanogenesis.

link

Appears Pohlman and Ruppel are describing half of a production-removal cycle.  And since surface waters release methane to the atmosphere, consumption can only take place on what's left in the water column.

Therefore, Algal blooms are not a sink, but rather a source.   

Methylphosphonate can also act as a substrate to methanogenesis.

Quote
Microbial methane production has traditionally been thought to be the exclusive purview of a specialized group of Archaea termed methanogens. These organisms are highly oxygen sensitive, and only produce methane in places where all the oxygen has already been consumed, like in lake and ocean sediments, or inside the guts of animals, including humans.

However, such traditional methanogenesis wasn’t enough to explain the large amount of methane coming out of the oceans, mostly because methane generated in ocean sediments has to travel a long way to get to the surface, and it usually gets eaten by other microorganisms termed methanotrophs (methane eaters) prior to being released into the atmosphere. Nevertheless, methane can be observed in high concentrations in surface waters worldwide, and this puzzle has been dubbed the “oceanic methane paradox.”

The first half of the marine methane puzzle was solved in 2009 by researchers at University of Hawaii and MIT. They discovered that microorganisms, frequently starved for phosphorous, would metabolize a phosphorous-containing compound called methylphosphonate, and in the process release a methane molecule. This was the first time that methanogenesis had been discovered occurring in water where oxygen was present, and importantly, happened in surface waters where the methane could make it to the atmosphere before being consumed by methanotrophs.

 

What remained a mystery was where all the methylphosphonate was coming from. In order for this “aerobic methanogenesis” to be able to explain 4% of the total methane in the atmosphere, there would have to be a huge amount of methylphosphonate in the ocean, but no one had observed that. In August, researchers from the University of Illinois working on soil microbes reported that microorganisms called Thaumarchaea create a large amount of methylphosphonate with a previously unknown set of genes. Now, it turns out that these Thaumarchaea are also one of the most abundant groups of microorganisms in the oceans, and surveys demonstrated these newly discovered genes in abundance throughout the world’s oceans, not only in Thaumarchaea, but also in other microbes that dominate the water column. The reason why methylphosphonate had not been previously observed was because it was bound to the microbial cells that make it, not freely dissolved in the water.  When these cells die, they have the potential to release that methylphosphonate which can be consumed by organisms that do aerobic methanogenesis, creating, as the authors describe, “a plausible explanation for the methane paradox.”
link


Oxic water column methanogenesis as a major component of aquatic CH4 fluxes
Quote
The relationship between CH4 and phytoplankton observed here (Fig. 2) has been hypothesized before to explain both the presence of metabolically active methanogens, and the recurrent metalimnetic and near-surface CH4 peaks in oxic lake9,10,18,19 and marine13,14,15,16,17 environments. We confirm this link experimentally, and further show that it generates a significant out flux of CH4 from the mesocosms to the atmosphere (Fig. 1b). These results in turn imply that factors influencing phytoplankton standing stock and GPP, such as grazing, nutrient availability and the physical structure of the water column, will have a strong bearing on pelagic CH4 dynamics and resulting CH4 emissions.

There are potentially large global implications for algal-driven oxic-water methanogenesis. CH4 emissions from surface waters, particularly from freshwaters2,3,4, are a major element of the global atmospheric CH4 budget, and we suggest here that the algal-mediated baseline flux is not only a major contributor to these overall aquatic CH4 emissions, but also one that is particularly sensitive to environmental change. As such, widespread and intensifying human- and climate-driven changes in pelagic nutrient availability47,48,49, terrestrial DOC inputs50,51 and physical structure of the water column47,48,51, which strongly shape aquatic algal dynamics47,51,52,53,54, may have major, but previously unconsidered, consequences for oxic water methanogenesis and aquatic CH4 emissions.
link


 
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Re: Arctic Methane Release
« Reply #426 on: October 13, 2017, 12:54:53 AM »
Yet... you are saying the way to fix or mitigate this is to release more carbon and methane into the ocean.
No. This is not what I am saying Captain Kiwi. Not even close.
Go back and read all my posts, <snip, N.>

« Last Edit: October 13, 2017, 01:12:09 AM by Neven »

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Re: Arctic Methane Release
« Reply #427 on: October 13, 2017, 07:46:34 AM »
That is not exactly what you said but you did, just recently, say this. And none of the articles and research you have referenced support this statement.

Every time methane is released (in small or large quantities) there will be a massive CO2 sequestration that causes a cooling effect that far outweighs the warming effect of methane released into the atmosphere.

You are essentially arguing that sub-sea permafrost degradation, regardless of how extensive, with the associated methane releases will serve to cool the planet.

Bollocks!
« Last Edit: October 13, 2017, 05:40:00 PM by Shared Humanity »

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Re: Arctic Methane Release
« Reply #428 on: October 14, 2017, 04:23:52 PM »
That is not exactly what you said but you did, just recently, say this. And none of the articles and research you have referenced support this statement.

Every time methane is released (in small or large quantities) there will be a massive CO2 sequestration that causes a cooling effect that far outweighs the warming effect of methane released into the atmosphere.

You are essentially arguing that sub-sea permafrost degradation, regardless of how extensive, with the associated methane releases will serve to cool the planet.

Bollocks!
i didn't say that.

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Re: Arctic Methane Release
« Reply #429 on: October 14, 2017, 06:16:29 PM »
i didn't say that.

Yeah, you kinda did. To repeat, here's what you wrote:

Every time methane is released (in small or large quantities) there will be a massive CO2 sequestration that causes a cooling effect that far outweighs the warming effect of methane released into the atmosphere.

Which can only be interpreted as a blanket statement that methane releases induce CO2 sequestration, which in turn cools the planet far more than the released methane warms it. But that conjecture seems to be based on only the Pohlman article from May, and even that article acknowledges that the net cooling effect may only occur during summer months, that faster seeps off East Siberia may be different, and that the ocean's ability to absorb CO2 is directly correlated to the amount of CO2-loving plankton present. IOW, the net cooling may be only a localized phenomenon.

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Re: Arctic Methane Release
« Reply #430 on: October 14, 2017, 06:49:02 PM »
i didn't say that.

Yeah, you kinda did. To repeat, here's what you wrote:

Every time methane is released (in small or large quantities) there will be a massive CO2 sequestration that causes a cooling effect that far outweighs the warming effect of methane released into the atmosphere.

Which can only be interpreted as a blanket statement that methane releases induce CO2 sequestration, which in turn cools the planet far more than the released methane warms it. But that conjecture seems to be based on only the Pohlman article from May, and even that article acknowledges that the net cooling effect may only occur during summer months, that faster seeps off East Siberia may be different, and that the ocean's ability to absorb CO2 is directly correlated to the amount of CO2-loving plankton present. IOW, the net cooling may be only a localized phenomenon.

He did not simply say it will always have a net cooling effect, he stated that the cooling effect of the resulting "massive CO2 sequestration" will "far outweigh" the warming effect of the increase in atmospheric methane.

Given the links to articles that he has posted in support of this claim (I have now read them) do not, in fact, support his claim, he has now become a contributor to whom I will no longer look for insight as to what is happening or going to happen in the Arctic.

(Edit) Oooops. Sorry JP. Just reread your comment and realize you also mentioned the overwhelming nature of the cooling that TB claims will occur.
« Last Edit: October 14, 2017, 08:34:22 PM by Shared Humanity »

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Re: Arctic Methane Release
« Reply #431 on: October 14, 2017, 08:39:00 PM »
Methane itself is not so difficult but its politicization within certain segments of the scientific community has gotten very ugly: methane is a threat to the paradigm, therefore its threat to the climate has to be belittled. That's a poor way to go though on climate risk assessment.

The first thing I do with a methane article is skim through to what the authors take for CO2 equivalency (by itself often belittled). If it's 20, that's rubbish, I don't read further. Time is better spent on straight science than reading another biased blast from yet another paradigm defender.

Not wanting methane is a very different thing from not getting methane.

I concur, and I note that the Obama Administration made much of the use of natural gas (largely from new fracking operations) as a bridge to a clean renewable energy economy (see the linked article).  However in addition to ignoring that the use of cheap natural gas can become a barrier to the use of clean energy, they also ignore both the natural gas leaks from such a natural gas dependent energy system and also the synergy between atmospheric methane from fossil fuel leaks and other reactive GHG in the atmosphere including natural methane emissions, N2O, upper atmospheric ozone etc.  Decision makers (and the AR5 scientists) all too often ignore, or underestimate) non-fossil fuel sources of atmospheric methane in over the next few decades, not only including from agricultural sources, but also from lakes, degrading permafrost (including from thermokarst lakes), degrading rainforests, wet lands and peat bogs, and methane hydrates.  Furthermore, they ignore the dangers that if we don't stay well below 2C, then numerous positive feedback mechanism will likely be triggered that will increase the effective equilibrium climate sensitivity this century in a non-linear manner with increasing temperature; so by ignoring that the GWP20 of methane may be as high as 105 (with a mean value of at least 85) they risk triggering multiple positive feedbacks before their dreams of negative emissions technology could ever hope to be implemented.  Finally, the life-span of methane in the atmosphere is extended the more concentration of chemically reactive GHG increase.

Title: "Natural Gas: Bridge or Barrier to a Clean Energy Future?"

http://www.renewableenergyworld.com/articles/2016/06/natural-gas-bridge-or-barrier-to-a-clean-energy-future.html

Extract: "Does anyone honestly believe that natural gas interests are going to simply strand these investments—gradually or otherwise?

Remember that natural gas is not clean. What it has going for it is: domestic availability; currently low price; relative cleanliness as compared to the dirtiest fossil fuel; and compatibility with the existing power structure.

Today’s evidence overwhelmingly points to the fact that current domestic and global efforts to reduce carbon emissions are unlikely to do more than slow the drift towards catastrophic climate change. Recent domestic and international action, e.g. the Clean Power Plan and the Paris Accords, are to be commended; they should not, however, be counted on as anything other than a good start. Absent the emergence of some new transformative energy technology or a radical re-thinking of climate science—based on solid evidence—that the Earth’s climate is going through a phase that will quickly correct, greater reliance on renewables is inevitable.

What happens when 20 years from now the world is about to cross the threshold marking the difference between acceptable and unacceptable levels of atmospheric carbon and rising temperatures? Efforts will be made to reduce further the amount of carbon and other greenhouse gases attributable to the extraction, transport and combustion of the principal remaining fossil fuel. Inevitably these efforts will be resisted by the natural gas industry, just as efforts of the past decade have been resisted by the coal industry.

Why? Because a great deal of money has been invested in a resource the world can no longer afford. The seeds of resistance to tomorrow’s need for an energy economy principally powered by clean renewable energy technologies and sustainable practices are being planted today. Policies too encouraging of natural gas, e.g. natural gas exporting, continued subsidization or reducing support for renewables, will inevitably lead to an industry that is “too big to be easily replaced!”

If policy makers fail to give true meaning to the phrase “a bridge technology,” then today’s bridge will become tomorrow’s barrier. History will repeat itself if the proper balance between a cleaner today and a clean tomorrow is not struck."

Edit: The first attached image shows the risk of high methane emissions from thermokarst lakes within a few decades, while the second & third images (from Isaken et al 2011) show how the GWP (effective radiative forcing) of methane increases with increasing atmospheric burden.

Isaksen, I. S. A., Gauss M., Myhre, G., Walter Anthony, K. M.  and Ruppel, C.,  (2011), "Strong atmospheric chemistry feedback to climate warming from Arctic methane emissions", Global Biogeochem. Cycles, 25, GB2002, doi:10.1029/2010GB003845.

http://onlinelibrary.wiley.com/doi/10.1029/2010GB003845/abstract
« Last Edit: October 14, 2017, 08:44:45 PM by AbruptSLR »
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Re: Arctic Methane Release
« Reply #432 on: October 14, 2017, 08:55:10 PM »
ASLR.....

Thank you for this wonderful post.

Thomas Barlow

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Re: Arctic Methane Release
« Reply #433 on: October 15, 2017, 09:04:21 PM »
That is not exactly what you said but you did, just recently, say this. And none of the articles and research you have referenced support this statement.

Every time methane is released (in small or large quantities) there will be a massive CO2 sequestration that causes a cooling effect that far outweighs the warming effect of methane released into the atmosphere.

You are essentially arguing that sub-sea permafrost degradation, regardless of how extensive, with the associated methane releases will serve to cool the planet.

Bollocks!

Me saying "Every time methane is released (in small or large quantities) there will be a massive CO2 sequestration that causes a cooling effect that far outweighs the warming effect of methane released into the atmosphere" is completely different than someone saying "the way to fix or mitigate this is to release more carbon and methane into the ocean", which is what Captain Kiwi changed it to.

Cid_Yama

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Re: Arctic Methane Release
« Reply #434 on: October 16, 2017, 08:06:41 PM »
Neither of those statements are true.
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Re: Arctic Methane Release
« Reply #435 on: October 16, 2017, 09:19:49 PM »
ASLR.....

Thank you for this wonderful post.

For what it is worth, when S&S (Dr Natalia Shakhova and Dr Igor Semiletov) published their 2011 findings I performed what I call a 95% confidence level scenario based engineering hazard assessment, SBEHA, of maximum methane emissions by 2100 and I previously generated the attached list, as a correction to the methane emissions assumed in RCP 8.5 (which we are essentially following at the moment).  You can use this information together with the radiative forcings calculated by Isaksen et al 2011.

Edit: For reference the second attached image gives the assumed atmospheric methane concentrations thru 2300 per the different RCP scenarios.

Edit 2, the third image from Hansen et al 2017 shows the observed atmospheric concentrations to those assumed by the RCP scenarios, indicating that we are currently closest to the RCP 8.5 scenario w.r.t. methane concentrations.

Edit 3, the fourth image shows the Mauna Loa atmospheric methane concentration from 2006 thru early Oct 2017, and it makes it clear that Hansen et al 2017 observed data errs on the side of least drama as it appears that by mid-2017 the mean Mauna Loa ppb will be around 1870 (or slightly above the RCP 8.5 scenario for mid-2017).
« Last Edit: October 17, 2017, 12:34:29 AM by AbruptSLR »
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Re: Arctic Methane Release
« Reply #436 on: October 17, 2017, 01:39:19 AM »
Just a quick observation on this methane-induced bloom malarky... carbon isn't the limiting nutrient. Yes, methane release will promote algal growth, but as in all oceans, blooms are limited by the availability of other nutrients. In the Southern Ocean it's largely iron, and in the Arctic it's thought to be nitrogen and phosphorus, depending on salinity and riverine input:
https://www.biogeosciences.net/7/3569/2010/bg-7-3569-2010.pdf

So yes, methane ought to encourage carbon draw-down, but only up to a point. Once the blooms get big enough, they will reach a limit and exhaust the local nutrients, at which point I would expect to see a lot more methane and CO2 released through decay.

Got to run, but I hope that's a useful input!

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Re: Arctic Methane Release
« Reply #437 on: October 17, 2017, 02:00:26 AM »
Avalonian, ++
The Arctic will exhibit nutrient limitations due to the lack of upwelling. Riverine inputs are seasonal.

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Re: Arctic Methane Release
« Reply #438 on: October 17, 2017, 05:48:46 AM »
ASLR....

Does RCP 8.5 mean a 5C temperature rise over pre-industrial by 2100?

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Re: Arctic Methane Release
« Reply #439 on: October 17, 2017, 03:16:28 PM »
ASLR....

Does RCP 8.5 mean a 5C temperature rise over pre-industrial by 2100?

The Recommended Concentration Pathways, RCPs, are assumed emission scenarios that result in the indicated amount of peak radiative forcing in the 2000 to 2100 timeframe (see the attached plot).  So RCP 8.5 means an assumed pathway of combined anthropogenic and natural feedbacks (assuming ECS around 3C), leading to 8.5 W/sq meter of radiative forcing by 2100.
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Capt Kiwi

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Re: Arctic Methane Release
« Reply #440 on: October 17, 2017, 08:04:27 PM »
“And for the runaway emissions scenario (RCP 8.5) it is  3.7°C.”

http://shrinkthatfootprint.com/climate-science-beginners

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Re: Arctic Methane Release
« Reply #441 on: October 17, 2017, 11:40:28 PM »
Searching for 'methane' at AGU17 abstracts gets you 530 abstracts, some of more interest than others.

https://agu.confex.com/agu/fm17/meetingapp.cgi/SearchResults/0

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Re: Arctic Methane Release
« Reply #442 on: October 18, 2017, 08:21:52 AM »
Bear in mind the IPCC came out in 2013.  What a difference a few years make.

Methane 'deliberately left out' of IPCC projections - UN Pachauri say's time about to run out on man
Quote
There are some possibilities that are deliberately left out of the IPCC projections, because we simply don’t have enough data yet to model them. Jason Box, a visiting scholar at the Byrd Polar Research Center told me in an email interview that: “The scary elephant in the closet is terrestrial and oceanic methane release triggered by warming.” The IPCC projections don’t include the possibility — some scientists say likelihood — that huge quantities of methane will be released from thawing permafrost and undersea methane hydrate reserves. Box said that the threshhold “when humans lose control of potential management of the problem, may be sooner than expected.”

The head of the IPCC, Rajendra Pachauri, speaks for the scientific consensus when he says that time is fast running out to avoid the catastrophic collapse of the natural systems on which human life depends. What he recently told a group of climate scientist could be the most chilling headline of all for the U.N. report:

"We have five minutes before midnight."
link


Recognizing this shortcoming, in the conclusions, the IPCC made this statement:

Quote
"The possibility of abrupt climate change and/or abrupt changes in the earth system triggered by climate change, with potentially catastrophic consequences, cannot be ruled out. Positive feedback from warming may cause the release of carbon or methane from the terrestrial biosphere and oceans."

 
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Re: Arctic Methane Release
« Reply #443 on: October 18, 2017, 08:31:47 AM »
This paper is from 1998, almost 20 years ago, but it points to another potentially unrecognized feedback that could make things much worse.

Polar stratospheric clouds: A high latitude warming mechanism in an ancient greenhouse world
Quote
The formation of Type II PSCs may be linked to tropospheric methane concentrations because oxidation of methane in the troposphere is a significant source of stratospheric water vapor (Lelieveld et al., 1993). Methane oxidizes to water vapor in the troposphere, and current observations suggest that approximately 10% of that water vapor diffuses to the stratosphere (Lelieveld et al., 1993).

Increased tropospheric methane concentrations may have led to greater amounts of stratospheric water vapor, creating greater areal extents of PSCs, and/or higher emissitivity values of the clouds during the Eocene.

The PSC mechanism is a very appealing explanation for high latitude warming in a greenhouse world for several reasons.

First, PSCs produce a greater magnitude of high latitude warming than any other climate forcing factor tested to date. Second, the warming is concentrated at high latitudes, and tropical temperatures are not affected. Third the warming is preferential in the winter season, corresponding more closely to proxy records of high latitude Eocene temperature (se .g., Zachose t al., 1994; Greenwood and Wing, 1995). Fourth, the mechanism of PSC warming is clearly defined, unlike other hypotheses for high-latitude warming (e.g., poleward oceanic heat transport (Sloan et al, 1995)). Lastly, a positive feedback mechanism amplifies the warming, through the connection between tropospheric warming and stratospheric cooling. As the troposphere warms in a greenhouse world, the corresponding increased cooling of the stratosphere could lead to larger areas with temperatures below ~ -190 K, leading to more extensive PSCs (Shine, 1988; Austin et al., 1992). This feedback makes PSCs an even more plausible explanation for high latitude warming during times of warm climate and high greenhouse gas concentrations, such as the middle Cretaceous (e .g., Huber et al., 1995), provided that atmospheric methane exists in sufficient concentrations.

The methane source for the PSCs originally was hypothesized to have been the greater area of wetlands that existed in the ancient greenhouse world (Sloan et al., 1992). Recent work has suggested that the release of methane clathrates to the atmosphere could provide another source of methane at times (Dickens et al., 1997; Bralower et al., 1997). Latest Paleocene marine and isotopic records suggest that an extreme warm "event" occurred, lasting less than 500,000 years and concentrated at high latitudes (Bralower et al., 1997).
Dickens et al. (1997) and Bralower et al. (1997) have suggested that the catastrophic release of methane clathrates could explain the latest Paleocene warming, via tropospheric greenhouse effects.

Not only would the clathrate-released methane have provided more of a source for PSCs, but a pulse of methane also might have increased either the residence time (Lelieveld et al., 1993; Lelieveld and Crutzen, 1992) and/or the amount of methane that diffused to the stratosphere to create PSCs. If so, extensive PSCs might have been an important climate modifier during such methanogenic "events".

Therefore we conclude that PSCs may have been an important climatic forcing factor during past warm climates, and that considering only the tropospheric effects of methane upon climate in paleoclimate studies omits significant mechanisms for potential modification of surface temperatures.
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Cid_Yama

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Re: Arctic Methane Release
« Reply #444 on: October 18, 2017, 09:05:44 AM »
Searching for 'methane' at AGU17 abstracts gets you 530 abstracts, some of more interest than others.

https://agu.confex.com/agu/fm17/meetingapp.cgi/SearchResults/0

This will be the year to go.  Wonder why it's in NO, it's always been in SF.
"For my part, whatever anguish of spirit it may cost, I am willing to know the whole truth; to know the worst and provide for it." - Patrick Henry

Shared Humanity

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Re: Arctic Methane Release
« Reply #445 on: October 18, 2017, 05:09:15 PM »
Reading this article from 20 years ago drives home a point that I already tended to believe. We already know all we need to know about AGW and climate change. We are simply choosing to ignore it at our peril.

TerryM

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Re: Arctic Methane Release
« Reply #446 on: October 18, 2017, 10:53:19 PM »
Reading this article from 20 years ago drives home a point that I already tended to believe. We already know all we need to know about AGW and climate change. We are simply choosing to ignore it at our peril.
Are we choosing to ignore it at our peril, or are they choosing to ignore it at our peril. >:(
Terry

Cid_Yama

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Re: Arctic Methane Release
« Reply #447 on: October 19, 2017, 03:16:18 AM »
Terry, yes Exxon knew the connection between FF burning and global warming in the 1970s.  In that sense, they decided they would rather face the consequences rather than relinquish the reins.

But, the thawing of the relic permafrost on the ESAS began 8,000 years ago when it was first inundated.  A geological process out of our control.

That earlier extinction events were associated with methane releases was first proposed in the early 90's.  The term Clathrate Gun Hypothesis, was coined by James Kennett in a paper published in 2003.

That was also the year that Semiletov first noticed methane releases on the ESAS, he had been studying the shelf since the early 1990s.  It was 2008, that he first warned the science community at both the EGU and AGU.

In 2004, John Acheson wrote an article in Energy Bulletin titled, Methane Burps: Ticking Time Bomb in the Arctic Tundra, bringing it to the public attention.

But, the public debate did not begin until after the publication of  Shakhova, Natalia; Semiletov, Igor (November 30, 2010). Methane release from the East Siberian Arctic Shelf and the Potential for Abrupt Climate Change.

It has been almost exactly a decade since Semiletov made his first warning, at which time he made the comment, "We can do nothing about it, of course."  But he felt that people needed to know.

So it comes down to, even had we not found out so late in the game, there really was nothing we could have done to stop it.  By the time our great-great-grandparents were born, it was already heading towards us like a freight train. We just didn't know about it until recently.

Had the Industrial Revolution not happened, it still would have caught us eventually.  Our fate was sealed when the ESAS was inundated, and we invented water management and irrigation starting the rise of modern civilization.

At this point, there is no way that any major government on this planet does not know.  The manufactured doubt is for public consumption, all a part of keeping BAU going as long as possible.

Knowing what I now know, I'm all for keeping BAU going as long as possible. (But not the manufactured doubt. That violates my principles.)   No good would come from alerting the masses to the end of the world.  But if you are intelligent enough to get it, you have a right to know.




   

 


       

« Last Edit: October 19, 2017, 05:33:15 AM by Cid_Yama »
"For my part, whatever anguish of spirit it may cost, I am willing to know the whole truth; to know the worst and provide for it." - Patrick Henry

miki

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Re: Arctic Methane Release
« Reply #448 on: October 19, 2017, 05:37:35 AM »

Had the Industrial Revolution not happened, it still would have caught us eventually.


Yes... but it would have taken far more time. And, who knows...
We gave it a good acceleration and an inexorable outcome.

A-Team

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Re: Arctic Methane Release
« Reply #449 on: October 19, 2017, 01:25:43 PM »
One aspect of this which is not GAU (geology as usual), raised by both S&S and separately by Wadhams, concerns anthropogenic warming of Arctic Ocean water at the depth of the continental shelf, ie at the interface with submerged permafrost. This could provide an accelerant to loss of impermeable gas cap, not so much by plain thermal diffusion as by cryo-geological mechanisms described by S&S.

Recall here that about a third of this ocean, especially on the Siberian side, is very shallow, well within range of wind, wave and tidal turbulent mixing. Early and persistent seasonal loss of ice cover  attributable to anthropogenic Arctic amplification allows enhanced solar heat adsorption and provides much longer fetches for wind to mix up stratification.

Wadhams sees a significant difference between submerged permafrost meeting sea water near the latter's freezing point of -1.8ºC vs contacting sea water above its own melting temperature which is more like 0ºC (since permafrost ice is freshwater ice formed on land). Consequently, geology-as-usual may be going off the trolley tracks. In this view, the late timing within the Holocene cycle is being seriously supplemented by man-made effects.

IP Semiletov is a co-author on 3 papers at AGU17. I did not see abstracts for N Shakhova; her four 2017 papers are listed below.

http://envisionation.co.uk/index.php/nick-breeze/203-subsea-permafrost-on-east-siberian-arctic-shelf-now-in-accelerated-decline

PP51B-1069: Deglacial remobilization of permafrost carbon to sediments along the East Siberian Arctic Seas
J Martens et al

Current climate change is expected to thaw large quantities of permafrost carbon (PF-C) and expose it to degradation which emits greenhouse gases (i.e. CO2 and CH4). Warming causes a gradual deepening of the seasonally thawed active layer surface of permafrost soils, but also the abrupt collapse of deeper Ice Complex Deposits (ICD), especially along Siberian coastlines. It was recently hypothesized that past warming already induced large-scale permafrost degradation after the last glacial, which ultimately amplified climate forcing. We here assess the mobilization of PF-C to East Siberian Arctic Sea sediments during these warming periods.

We perform source apportionment using bulk carbon isotopes  together with terrestrial biomarkers (CuO-derived lignin phenols) as indicators for PF-C transfer. We apply these techniques to sediment cores  from the Chukchi Sea and the southern Lomonosov Ridge.

We found that PF-C fluxes during the Bølling-Allerød warming (14.7 to 12.7 cal ka BP), the Younger Dryas cooling (12.7 to 11.7 cal ka BP) and the early Holocene warming (until 11 cal ka BP) were overall higher than mid and late Holocene fluxes. In the Chukchi Sea, PF-C burial was 2x higher during the deglaciation (7.2 g m-2 a-1) than in the mid and late Holocene (3.6 g m-2 a-1), and ICD were the dominant source of PF-C (79.1%). Smaller fractions originated from the active layer (9.1%) and marine sources (11.7%).

We conclude that thermo-erosion of ICD released large amounts of PF-C to the Chukchi Sea, likely driven by climate warming and the deglacial sea level rise. This contrasts to earlier analyses of Laptev Sea sediments where active layer material from river transport dominated the carbon flux.

Preliminary data on lignin phenol concentrations of Lomonosov Ridge sediments suggest that the postglacial remobilization of PF-C was one order of magnitude higher (10x) than during both the preceding glacial and the subsequent Holocene. We will apply source apportionments between coastal erosion of ICD and river export of active layer material for the outer East Siberian Arctic Seas.

Our findings demonstrate remobilization of PF-C during past warming events and suggest that current climate change might cause a similar cascade of permafrost destabilization and, thus, accelerate climate warming.


PP54A-03: Late Holocene sea ice conditions in Herald Canyon, Chukchi Sea
C Pearce et al

Sea ice in the Arctic Ocean has been in steady decline in recent decades and, based on satellite data, the retreat is most pronounced in the Chukchi and Beaufort seas. Historical observations suggest that the recent changes were unprecedented during the last 150 years, but for a longer time perspective, we rely on the geological record. For this study, we analyzed sediment samples from two piston cores from Herald Canyon in the Chukchi Sea, collected during the 2014 SWERUS-C3 Arctic Ocean Expedition.

The Herald Canyon is a local depression across the Chukchi Shelf, and acts as one of the main pathways for Pacific Water to the Arctic Ocean after entering through the narrow and shallow Bering Strait. The study site lies at the modern-day seasonal sea ice minimum edge, and is thus an ideal location for the reconstruction of past sea ice variability.

Both sediment cores contain late Holocene deposits characterized by high sediment accumulation rates (100-300 cm/kyr). Core 2-PC1 from the shallow canyon flank (57 m water depth) is 8 meter long and extends back to 4200 cal yrs BP, while the upper 3 meters of Core 4-PC1 from the central canyon (120 mwd) cover the last ~3000 years. The chronologies of the cores are based on radiocarbon dates and the 3.6 ka Aniakchak CFE II tephra, which is used as an absolute age marker to calculate the marine radiocarbon reservoir age.

Analysis of biomarkers for sea ice and surface water productivity indicate stable sea ice conditions throughout the entire late Holocene, ending with an abrupt increase of phytoplankton sterols in the very top of both sediment sequences. The shift is accompanied by a sudden increase in coarse sediments (> 125 µm) and a minor change in δ13Corg.

We interpret this transition in the top sediments as a community turnover in primary producers from sea ice to open water biota. Most importantly, our results indicate that the ongoing rapid ice retreat in the Chukchi Sea of recent decades was unprecedented during the last 4000 years.

PP54A-02: The Deglacial to Holocene Paleoceanography of Bering Strait: Results From the SWERUS-C3 Program (Invited)
M Jakobsson

The multi-disciplinary SWERUS-C3 Program was carried out on a two-leg 90-day long expedition in 2014 with Swedish icebreaker Oden. One component of the expedition consisted of geophysical mapping and coring of Herald Canyon, located on the Chukchi Sea shelf north of the Bering Strait in the western Arctic Ocean.

Herald Canyon is strategically placed to capture the history of the Pacific-Arctic Ocean connection and related changes in Arctic Ocean paleoceanography.

We provide a new age constraint of 11 cal ka BP on sediments from the uppermost slope for the initial flooding of the Bering Land Bridge and reestablishment of the Pacific-Arctic Ocean connection following the last glaciation. This age corresponds to meltwater pulse 1b (MWP1b) known as a post-Younger Dryas warming in many sea level and paleoclimate records.

High late Holocene sedimentation rates in Herald Canyon permitted paleo-ceanographic reconstructions of ocean circulation and sea ice cover at centennial scales throughout the late Holocene. Evidence suggests varying influence from inflowing Pacific water into the western Arctic Ocean including some evidence for quasi-cyclic variability in several paleoceanographic parameters,  such as micro-paleontological assemblages, isotope geochemistry and sediment physical properties.


U13B-13: Implementation of an acoustic-based methane flux estimation methodology in the Eastern Siberian Arctic Sea
EF Weidner et al

Quantifying methane flux originating from marine seep systems in climatically sensitive regions is of critically importance for current and future climate studies. Yet, the methane contribution from these systems has been difficult to estimate given the broad spatial scale of the ocean and the heterogeneity of seep activity.

One such region is the Eastern Siberian Arctic Sea (ESAS), where bubble release into the shallow water column (<40 meters average depth) facilitates transport of methane to the atmosphere without oxidation. Quantifying the current seep methane flux from the ESAS is necessary to understand not only the total ocean methane budget, but also to provide baseline estimates against which future climate-induced changes can be measured.

At the 2016 AGU fall meeting, we presented a new acoustic-based flux methodology using a calibrated broadband split-beam echosounder. The broad (14-24 kHz) bandwidth provides a vertical resolution of 10 cm, making possible the identification of single bubbles. After calibration using 64 mm copper sphere of known backscatter, the acoustic backscatter of individual bubbles is measured and compared to analytical models to estimate bubble radius. Additionally, bubbles are precisely located and traced upwards through the water column to estimate rise velocity. The combination of radius and rise velocity allows for gas flux estimation.

Here, we follow up with the completed implementation of this methodology applied to the Herald Canyon region of the western ESAS. From the 68 recognized seeps, bubble radii and rise velocity were computed for more than 550 individual bubbles. The range of bubble radii, 1-6 mm, is comparable to those published by other investigators, while the radius dependent rise velocities are consistent with published models. Methane flux for the Herald Canyon region was estimated by extrapolation from individual seep flux values.

1. Sonar gas flux estimation by bubble insonification: application to methane bubble flux from seep areas in the outer Laptev Sea
I Leifer, D Chernykh, N Shakhova…
https://www.the-cryosphere.net/11/1333/2017/tc-11-1333-2017.pdf open access

Sonar surveys provide an effective mechanism for mapping seabed methane flux
emissions, with Arctic submerged permafrost seepage having great potential to significantly
affect climate. We created in situ engineered bubble plumes from 40 m depth with fluxes ... seepage-mapped spatial patterns suggested subsurface geologic control attributing methane fluxes to the current state of subsea permafrost.

On a century timescale, methane (CH4) is the next most important anthropogenic greenhouse gas after CO2. However, on a decadal timescale comparable to its atmospheric lifetime, CH4 is more important to the atmospheric radiative balance than CO2 (Forster 2007; Fig. 2.21 https://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter2.pdf)

ESAS seepage is on a dramatically larger scale with∼ 30 000 plumes manually identified in just two transects. Seepage densities up to ∼ 3000 seep bubble plumes per km2 were found transecting
a single hotspot. Based on the hotspot size (18 400 km2), an order of magnitude estimate suggests 60 million seep plumes for the hotspot alone.


2. The origin of methane in the East Siberian Arctic Shelf unraveled with triple isotope analysis
CJ Sapart, N Shakhova, I Semiletov, J Jansen…
https://www.biogeosciences.net/14/2283/2017/bg-14-2283-2017.pdf open access

CH4 concentration and triple isotope composition were analyzed on gas extracted from sediment and water sampled at numerous locations on the shallow ESAS from 2007 to 2013. We find high concentrations (up to 500 µM) of CH4 in the pore water of the partially thawed subsea permafrost of this region.

For all sediment cores, both hydrogen and carbon isotope data reveal the predominant occurrence of CH4 that is not of thermogenic origin as it has long been thought, but resultant from microbial CH4 formation. At some locations, meltwater from buried meteoric ice and/or old organic matter preserved in the subsea permafrost were used as substrates.

Radiocarbon data demonstrate that the CH4 present in the ESAS sediment is of Pleistocene age or older... Our sediment data suggest that at locations where bubble plumes have been observed, CH4 can escape anaerobic oxidation in the surface sediment.


3. Current rates and mechanisms of subsea permafrost degradation in the East Siberian Arctic Shelf
N Shakhova, I Semiletov, O Gustafsson…
https://www.nature.com/articles/ncomms15872 open access

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 ∼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.


4. Discovery and characterization of submarine groundwater discharge in the Siberian Arctic seas: a case study in the Buor-Khaya Gulf, Laptev Sea
AN Charkin, MR van der Loeff, NE Shakhova 2017
https://www.the-cryosphere.net/11/2305/2017/tc-11-2305-2017.pdf open access

It has been suggested that increasing terrestrial water discharge to the Arctic Ocean
may partly occur as submarine groundwater discharge (SGD), yet there are no direct
observations of this phenomenon in the Arctic shelf seas... Another possible mechanism for preventing taliks from freezing and/or preventing talik formation could be groundwater flow through coastal sediments, especially in the areas underlain by faults
« Last Edit: October 22, 2017, 11:45:11 AM by A-Team »