salbers
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Everything posted by salbers
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This was during the annual GMD conference held in the building where I work. I think this desire for more obs has been expressed a number of times over the years. Curiously I didn't much see much reference to the Arctic Ocean and ESAS methane in this conference program.
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These folks, also from ESRL/GMD are mentioning the value of in-situ measurements... http://www.esrl.noaa.gov/gmd/annualconference/abs.php?refnum=86-120409-A
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I think the Beaufort side is where those NASA/NCAR aircraft measurements were as recently posted in this thread (#627).
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Hard to say exactly, though I haven't seen much in the way of rebuttal of what S&S are warning about. At a minimum we need much more thorough monitoring of this region to look for corroboration of any acceleration in release or related changes. Looking to the past, it's true this probably hasn't happened in the previous ice ages over the past 400000 years or so, though it's unclear whether these periods had the same setup and shallowness of the ESAS. Over Earth's history in general, this type of thing may well have happened, given the past greatly elevated levels of CO2.
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Just a bit of alliterative humor. Though it is something that is possible, given the unique combination of warming temperatures with sediments on a shallow shelf becoming unstable...
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Yes, weird and not good ? It's interesting that the article mentions possible biological activity in surface waters being the source. However the link below has an informative video that does show the flight path north of Alaska on the edge of the ESAS, and they do mention the shallow ocean sediments being a possible source of their enhanced methane measurements. http://hippo.ucar.ed...ns-from-hippo-i
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Well I agree you've been talking about a majority amount, so in that context I'd suggest it's a somewhat irrelevant point.
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The thing is that even a minority of the available methane would still be sufficient to cause a significant climate impact. And Wx Rusty is right about the short term CH4 being in tandem with the long term conversion to CO2. The latter is more of an irreversible process, as the mechanisms to pull CO2 from the atmosphere are somewhat limited. Which is more of a threat depends on the exact rate of release of CH4. The S&S and related papers are fairly suggestive of instability, aren't they? Over time more journal papers will likely be coming out, as it takes time to publish. So this is a nuanced discussion of risk assessment to be sure.
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Well this potential has been discussed in many posts so far. Perhaps you might want to clarify how many Gt per year of methane and the percent probability to give us a point of reference?
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It's not 100% definite, though this paper and other papers/letters that cite it suggest it is enough of a possibility to take seriously. Also, there's enough methane in the ESAS so only a relatively small proportion would still have a climate impact.
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If you review this thread you would find peer reviewed papers such as this: http://www.sciencemag.org/content/327/5970/1246.abstract
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Video from 2011 ESAS expedition, posted Jan 30. 2012... And here's an older 2010 video interview from Natalia S. To update this earlier post, the Feb 9th IARC seminar has been rescheduled for May 31st. Abstract available here: http://www.iarc.uaf....nar-series/2011 May 31st The IARC based Russia-US Siberian Shelf Studies (2003-2011): results and challenges Speakers: Natalia Shakhova, Igor Semiletov 1:30 PM - 2:30 PM, 401 Akasofu Building The Arctic Ocean is surrounded by permafrost, which is being degraded at an increasing rate under conditions of warming which are most pronounced in Siberia and Alaska. Sub-sea permafrost is much more vulnerable than its terrestrial counterpart, because it experienced a drastic change in its thermal regime due to inundation by the ocean and consequent warming by as much as 12-17˚C, prior to the current ongoing climate change. Thaw and release of organic carbon (OC) from Arctic permafrost is postulated to be one of the most powerful mechanisms causing a net redistribution of carbon from land and ocean to the atmosphere. This report summarizes current understanding of transport and fate of OC to and within the East Siberian Arctic Shelf (ESAS) and processes determining carbon dioxide (CO2) and methane (CH4) fluxes from the ESAS to the atmosphere achieved from analyzing the data sets obtained on 20 expeditions performed from 1999 to 2011. The shallow ESAS is a unique area of the World Ocean where ~80% of predicted sub-sea permafrost exists. This study of the ESAS was aimed at investigating how redistribution of old carbon from degrading terrestrial and sub-sea permafrost and from coastal erosion contributes to the carbon pool of the ESAS, and which factors control CH4 and CO2 emissions from the ESAS. This report describes selected results achieved by a developing international scientific partnership that has been crucial at every stage of the study and will be even more important in the future.
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This shows the methane levels were roughly level from 2000-2006. And from 2006 onward, the period of the surface observation uptick, we see here on the order of 2.5 ppb/yr rise. This assumes the baseline has no trend beyond an annual cycle. Here's a link to another surface plot, from Mauna Loa showing roughly 6ppb yr since 2006. http://upload.wikime...s_obs_03437.png
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This is a video of an ESAS expedition from a few years ago - nice to see some views from on the ship.
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Has it been mentioned yet this calculator has a thread on RealClimate? http://www.realclima...ere/#more-10545 By the way, the methane concentration Y-axis on the previous post is a bit confusing to me, is it just 0.5 -3.0 parts per billion? That's 1000 times too small. Will be interesting to see the latest hourly data as well.
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Thanks for the link. Any chance some revisions were made prior to the December acceptance date? I see though this is mainly a survey paper of previous findings.
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TerryM, Do you know what journal S&S's paper will be in? Is this something beyond the SWIPA book chapter draft that is now available? Also, there is an upcoming S&S seminar on Feb 9th. http://www.iarc.uaf....d=1323818876406 Looking ahead further, I wonder if this topic will be covered at the next ESRL/GMD global monitoring conference? http://www.esrl.noaa.gov/gmd/annualconference/ Thanks, Steve
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By the way, the section 5.3.4.3 is titled "Trace gas emissions from subsea permafrost", so it might indeed be a draft of the book chapter we've been waiting for from Shakhova and Semiletov.
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Here's the SWIPA website that I'm starting to look through (as in post #86). This will have the upcoming book chapter by Shakhova and Semiletov... http://amap.no/swipa/ Here is their 80MB pre-print draft of Background Science. Chapter 5 covers permafrost and contains 62 pages. Section 5.3.4.3 talks about future subsea permafrost releases. The end of the draft section suggests 800Gt of CH4 could be ready for sudden release... http://amap.no/swipa/CombinedDraft.pdf
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Indeed - nice plot that helps give some perspective. We see methane going from about half the CO2 forcing at the present time to about twice the forcing in a few decades. That's kind of a good benchmark to see if the worst case scenario from either land-based or ESAS based methane could exceed 1Gt/yr of methane flux. Also, interesting that a 2 Gt/yr sustained release gives about the same maximum radiative forcing as a 50Gt instantaneous release.
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Yes, good summary at Skeptical Science. I look forward to their Part 2, featuring an interview with Dr. Natalia Shakhova covering some of the important questions that remain.
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Meanwhile, the land-based permafrost is estimated to increase to about 1 Gt/yr in this abstract: http://onlinelibrary...0527.x/abstract
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Thanks for finding this. I was attempting to find this presentation in the 2011 symposium.
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Please try and elaborate further (beyond post #453) on the context with how it fits into the numbers I'm using. Most of the reasoning I'm presenting makes sense I think. What fraction of the 1400Gt "ready" to release can possibly be released over what time period? Are you confident it is less than 1/2000th of this over a 1 year time period? This in turn is about 100 times the current steady release component. The total release right now probably isn't much more than the 6-8Mt steady component, otherwise we'd have a faster global rate of rise. As Vergent mentions Archer in 2007 believes it is a relatively small fraction, though as we can see in the recent RC thread Vergent along with others seems to be able to challenge Archer on this. We'll see how the scientific debate continues with players like Shakhova and Archer.
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We are trying to use scientific references when possible. That should qualify at least some of the posts in this thread? We are mainly speculating in advance of future publications that should help clarify things.