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  1. “instead of it being trapped by fresh water and oxidized to CO2 in the water”
    I’m guessing the use of the word fresh was a typo, as this is seawater here.

    [Response: It's amazing how incompetent I am at proof-reading! David]

    Comment by Thomas — 6 Mar 2010 @ 10:31 AM

  2. Glad to read the sober and conservative tone of this post!

    On the other hand, would it be true to say that a prediction of AGW has come to pass? Increased venting of methane from Arctic resevoirs has often been mentioned .. methane concentrations have been increasing in the atmosphere … but NASA do not include it among their 5 indicators of Global Warming (Sea Level, Arctic Sea Ice, Atmospheric CO2 Concentration, Global Surface Temperature, Ozone Hole).

    How good or bad is this news? Does it push the indicators more into the red? Or are they “as you were”? Assume these results will be confirmed.

    http://www.realclimate.org/index.php/archives/2010/03/arctic-methane-on-the-move/

    Comment by Toby — 6 Mar 2010 @ 10:34 AM

  3. First off, David, thanks for a very nice summary. I think this information will be accessible to all.

    More importantly, this piece shows how scientists are not “alarmists” despite the constant claim that they are.

    Thank you.

    Comment by Scott A Mandia — 6 Mar 2010 @ 10:37 AM

  4. Thank you for this (and real climate generally!). I’ve been worried about the impications of this paper since I read a reference to it in a blog suggesting that this was really bad news. Thankyou for putting it in context.

    Comment by Louise D — 6 Mar 2010 @ 10:55 AM

  5. Subscription required for the Science article.

    Thank you for the great article. I’m less worried about methane now.

    Comment by Edward Greisch — 6 Mar 2010 @ 10:57 AM

  6. Here’s a graph from the Shakhova paper: Methane Fluxes Venting to the Atmosphere from the East Siberian Arctic Shelf

    Comment by Jim Galasyn — 6 Mar 2010 @ 11:04 AM

  7. Thanks for the review, David.

    I would guess that hydrates are not involved in this case as the sea in this area is so shallow, and it’s entirely outgassing from organic-rich sediments beneath the permafrost?

    Cheers – John

    [Response: I think that's a possibility for the Siberian margin data, still an open question. David]

    Comment by John Mason — 6 Mar 2010 @ 11:22 AM

  8. Thanks David, this is very helpful. And I think Scott is right; this can be cited as an example of how Real Climate brings reality to the table, correcting misunderstandings in either direction.

    By the way, I just finished “The Climate Crisis.” Thank you for this good summary and commentary on the IPCC 2007 report. I did note a couple of minor things that I think got past the editors and will give them here in case others have the book.

    p. 14, “Figure 6.14 in Chapter 6″ should be “Figure 3.18 in Chapter 3″

    p. 51, Figure 3.7, I believe the sign is reversed on the PDSI 1 axis

    Comment by Ron Taylor — 6 Mar 2010 @ 11:36 AM

  9. It’s nice to see this news put into context. I wonder – will atmospheric methane will become more significant in the future? We could have a big impact on atmospheric CO2 by reducing emissions from fossil fuel burning, but it might be more difficult to reduce the emissions of methane from wetlands and oceans, and the CO2 resulting from it. Is that the case?

    Comment by Icarus — 6 Mar 2010 @ 11:49 AM

  10. More metaphors please.

    I really like the metaphor of being in a broken car about to crash at 80mph. A few people saw the crash coming, some now see it unfolding. Too many have not seen it yet, some will never see it. Some completely deny the possibility of a crash.

    Thanks for explaining it all.

    Comment by Richard Pauli — 6 Mar 2010 @ 11:55 AM

  11. I get reamed sometimes for making points like those in this important methane update (pushing back against some of the overheated coverage elsewhere), so this is very welcome. Great driving analogy, proving that scientists can do some of their own communicating (in a world of shrinking conventional media). More background from Dlugokencky, Martin Heimann, Euan Nisbet and others on Dot Earth: http://j.mp/ch4heat

    Comment by Andy Revkin — 6 Mar 2010 @ 12:36 PM

  12. David wrote: “What’s missing from these studies themselves is evidence that the Siberian shelf degassing is new, a climate feedback, rather than simply nature-as-usual, driven by the retreat of submerged permafrost left over from the last ice age. However, other recent papers speak to this question.”

    The other recent papers you discuss still seem to be ambiguous on that point.

    [Response: very]

    What additional science is needed in order to definitively determine whether this — and other such methane emissions that are being observed — are, in fact, new and caused by AGW, and are therefore actual AGW feedbacks; and if so, whether and how rapidly they are increasing?

    [Response: They need to figure out where the methane is coming from and why. Then wait and see how it changes with time. David]

    Comment by SecularAnimist — 6 Mar 2010 @ 12:49 PM

  13. RE: “CO2 is plenty to be frightened of…”
    Yep, and it keeps contributing to the three years of steady Artic ice growth since the low in 2007! We are shivering all this winter, all over the northern hemisphere with the blizzards, the record snow, record cold, snow in ALL fifty states for the first time that we know of…oh geez! This CO2 issue has the entire population of Earth worried that if levels keep rising, it is gonna continue to get colder and colder each winter. Check out the latest sea ice extent: http://nsidc.org/data/seaice_index/daily.html

    [Response: You win the distorted cherry pick of the day award--so far.--Jim]

    Comment by Mike Strong — 6 Mar 2010 @ 12:54 PM

  14. So, how do we capture and burn it and turn it into energy that can be used to displace fossil fuels?

    If it’s going to leak into the atmosphere, let’s figure out how to make it do something useful in the process.

    [Response: It is a fossil fuel. David]

    Comment by FurryCatHerder — 6 Mar 2010 @ 1:20 PM

  15. Tamino, last August, posted graphs (here) which suggest that a spike in both Arctic and Antarctic methane started in the last couple of years. Have those spikes turned down or is his data simply too speculative?

    Comment by Francis — 6 Mar 2010 @ 1:21 PM

  16. Hi David,

    Thanks for the calm, thoughtful, and well-written article. I think you missed part of the reason methane releases capture people’s imaginations: it’s exactly their shorter-term nature. The slow, steady creep upwards of CO2 is, sadly, just too gradual to get people’s attention. Even the names play a part; CO2 sounds innocuous. Methane sounds dangerous. It catches on fire if you hold a match to it!

    It’s like a canary in a coal mine. The rational approach for most of us is, don’t go into poorly ventilated and supported holes in the ground. But given that you know you’re in dangerous territory, and have decided to put up with that, the canary tells you when you’re in more urgent trouble.

    SecularAnimist, if you’re truly secular, you’ll stop putting “definitively” in italics. Science, sadly, doesn’t work that way; it’s like civil court, where you make big decisions on a preponderance of evidence, not criminal court, where you only act if you’re beyond a reasonable doubt. The deniers go even further, saying they want proof, in all caps. Unfortunately, the climate doesn’t work that way. For true absolutes, you have to go to religion.

    Andy, IMHO, half the reason you get reamed is not your factual stance, but the way you give the impression that you’re trying to put people to sleep on these important issues. Somehow your writing implies that, if this methane release were worse, you’d still be looking for some little ironic twist to your writing, and scratching around for someone to give the other side of the story, whether there really was one or not. I don’t know how you do this, or the reasons, but that’s the impression that comes across.

    Whereas with David’s writing, I get the impression that if it were worse, he’d do everything in his power to clearly and forcefully communicate that to people. (Though, at the margin, I doubt David could bring himself to type in ALL CAPS if his chair had caught on fire.)

    Cheers,

    Bud

    [Response: At the moment I'm in greater danger of my laptop catching fire, but I probably wouldn't type in all caps in that case either. David]

    Comment by Bud Smith — 6 Mar 2010 @ 1:46 PM

  17. Re: 13

    So I guess that humans are getting slower in the last months, because noone has beaten Usain Bolt’s 100 m since last August…

    Comment by Ezequiel — 6 Mar 2010 @ 1:53 PM

  18. Nice to see a little bit of restraint. In the usual ‘Oh My God’ world of panic stricken chickens they would all be screaming for a solution right about now.
    However I am about to ask something that has occurred to me whilst reading the post and all the comments that may throw a spanner into the works.
    You say that the methane is out-gassing at a lower rate than CO2 is being released from other sources (peat bogs and wetlands etc) however the rate is constantly fluctuating so in my view (all be it a narrow one) I suspect that its part of a process that’s like climbing a set of stairs. There is no doubt that carbon emissions are still rising and to add a gas that is 20 times more powerful as a global warming gas into the air in sudden out-gassing events, even if these are only a few years apart, builds a step rise in Carbon content in the atmosphere that will subsequently become the plateau before the next big methane out-gassing event, regardless as to where it comes from. I hope that makes sense?
    I suspect that the methane that has out-gassed from the hydrates changes to CO2 in the atmosphere before it returns to the Earth as stored carbon. This is what I would hazard a guess at happens in clouds which are just vapour equivalents of water bodies. How does this affect the whole issue? Surely with CO2 being a longer lived global warming/climate changing gas this also exacerbates the problems?
    Oh and I had another look at the Horizon ‘Global Dimming’ episode the other night. Still all a bit spooky to think it could all go either way.

    Comment by Kev Coleman — 6 Mar 2010 @ 1:58 PM

  19. Response by David @ 14:

    [Response: It is a fossil fuel. David]

    Only for extremely loose definitions of the term “fossil fuel”. But that’s also besides the point — coal isn’t “leaking” into the atmosphere, it has to be dug out of the ground with considerable effort, and oil doesn’t just jump into our gasoline tanks. Even if methane hydrates are a “fossil fuel”, it would appear that it is venting to the atmosphere for free, and whether we like it or not.

    Comment by FurryCatHerder — 6 Mar 2010 @ 2:01 PM

  20. Ice and clathrates have sharp melting points. Conventionally, we assumed that there would be a gradual melting of these compounds from south to north, and that somewhere in the “north” it was always colder than 0C. (Even guys that would not write it in formal context, used the concept in casual contexts.) This notion gave us the idea of gradual over all melt for next few years. Now, we have to admit that these compounds are also melting from the Arctic Ocean south.

    We can no longer trust the Arctic sea ice to be a reliable “icebox” keeping the “north” cold. We have to see the reported CH4 releases as part of the reports of declining and “rotting” sea ice. Now, we also have to assume that carbon will be released as tundra melts from south to north AND as it melts from north to south as a result of warming Arctic waters and declining sea ice.

    Whether this is “catastrophic” or not depends our economic, engineering, and planning horizon. In the view of a corporate executive, looking at next quarter’s profits – not at all “catastrophic”. In the view of a congressman looking toward his next election, maybe. In the view of a parent looking at his children’s and grandchildren’s future, I think “catastrophic” is exactly the right word.

    We need to get all the corporate executives and all the congressmen thinking about our children.

    Comment by Aaron Lewis — 6 Mar 2010 @ 2:18 PM

  21. The main post is missing a stop-the-italic tag (or has an excess start-italic tag) in this paragraph, or maybe it’s having the wrong kind of bracket?

    {Note: Edited Toyota velocities to reflect relative radiative forcings of anthropogenic CO2 and methane. David]

    [Response: Thanks--fixed.]

    —–
    On the seabed methane — we can hope there are good maps of the seabed there (perhaps the Navy would have them, albeit likely classified). If so they can look for changes in the size and distribution of pingos.

    Interestingly, pingos used to be considered the result of freezing ice, but
    http://www.google.com/search?q=methane+seabed+pingo

    Comment by Hank Roberts — 6 Mar 2010 @ 2:23 PM

  22. The Toyota example is taking some cheap points. I get the math, but the reality is an accident at 60 MPH in a modern car is survivable. At 90 MPH you are dead. So there is a huge difference.

    [Response: OK, so damage probably doesn't scale linearly with velocity. Maybe you liked it better 70 / 90 mph. David]

    The rest of the tone is quite good and helpful. The point about ocean methane being much lower than the land methane emissions is very helpful. My reading of the Arctic sea shelf is that it shallow and therefore there is more methane buried underneath?

    I had two followup questions:

    1) If there is more methane around than previously accounted for, does that mean historical models that didn’t account for that extra methane are not working correctly?
    2) Would extra methane near the Artic circle account for more warming there locally?

    [Response: 1. It means the budgets have uncertainties that can accommodate this. 2. Methane is mostly well-mixed in the air, except when they catch a plume like they did, so the warming from it is mostly global. David]

    Comment by charlie — 6 Mar 2010 @ 2:24 PM

  23. Unclosed italic tag right betwee ‘{‘ and ‘Note’. I wonder what happens if i close it here

    I posted a comment on the previous thread, and with the permission of the moderators, I will repeat it here:

    Re:Shakhova methane article:

    I was directed to

    http://www.global-chance.org/IMG/pdf/CH4march2008.pdf

    by Mr. Lou Grinzo at climateprogress. In Figure 4 and table 2, a comparison is made between relative global warming potential of sustained releases of CH4 as compared to CO2 at different time horizons. The effect of a sustained release of CH4 has the same GWP as that of a sustained release of 81 times the amount of CO2 over a time of 20 years.The factors for 50,100,250 and 500 years are 57,39,21,and 13.

    The authors make the case that using the 21 multiplier appropriate for century timescales is not appropriate, especially in the early decades where GWP would be underestimated by a factor of 80.

    I see an estimate of 3.8 teragram/yr CH4 release from North Siberian Lakes in Zimov, Nature, v443, pp71-75, 2006. This has increased by 58% since 1974. Shakhova has 8 Tg/yr from the seabed.

    Only including these we have 8 Tg from the seabed, 4 from the lakes, for 12 Tg annual CH4 out. 12Tg of CH4 for twenty years has a GWP over that period of 0.72 Pg sustained CO2 release. I believe that by comparison, annual human fossil and land use CO2 emission is around 30 petagram, so thats round 2% extra in terms of GWP over 20 years.

    Not huge, but definitely significant.

    If these CH4 releases rise quickly, say by a factor of 10, we cook much quicker. Of course I might have done the math wrong.

    sidd

    [Response: I'm sure you're right, a factor of 10 increase in CH4 emission from the Arctic would be serious and bad. David]

    Comment by sidd — 6 Mar 2010 @ 2:29 PM

  24. Metacomment — Suddenly everything is all in italics. Disconcerting.

    [Response: Fixed, thanks.--Jim]

    Comment by David B. Benson — 6 Mar 2010 @ 2:41 PM

  25. You seem to be missing a [/i] from the EDIT there, David. We’re all emphasized down here! }|:op
    Anyway, thanks for this discussion, interesting stuff, if somewhat disconcerting (I don’t dispute that CO2 is enough to be worried about, but observing feedbacks kicking in isn’t exactly adding any feeling of comfort).

    Comment by werecow — 6 Mar 2010 @ 2:46 PM

  26. A small correction to the reference list: “Shakhova” is twice misspelt “Shakova”, as I discovered when accessing the GRL 2005 article.

    Thank you for an excellent post.

    [Response: Fixed now, thanks. David]

    Comment by Andy S — 6 Mar 2010 @ 2:48 PM

  27. Hi to all.I’m an amateur climate guy who reads a lot about global warming.I’ve followed all the press releases and most of the science since 1987.RealClimate is wonderful, and an excellent source of reliable information.As I’ve said before, methane is an extremely dangerous component to global warming.Comment # 20 is correct.There is a sharp melting point to frozen methane.A huge increase in the release of methane could happen within the next 50 years.At what point in the Earth’s temperature rise and the rise of co2 would a huge methane melt occur?No one has answered that definitive issue.If I ask you all at what point would huge amounts of extra methane start melting, i.e at what temperature rise of the ocean near the Artic methane ice deposits would the methane melt, or at what point in the rise of co2 concentrations in the atmosphere would the methane melt, I believe that no one could currently tell me the actual answer as to where the sharp melting point exists.Of course, once that tipping point has been reached, and billions of tons of methane outgass from what had been locked stores of methane, locked away for an eternity, it is exactly the same as the burning of stored fossil fuels which have been stored for an eternity as well.And even though methane does not have as long a life as co2, while it is around in the air it can cause other tipping points, i.e. permafrost melting, to arrive much sooner.I will reiterate what I’ve said before on this and other sites.Methane is a hugely underreported, underestimated risk.How about RealClimate attempts to model exactly what would happen to other tipping points, such as the melting permafrost, if indeed a huge increase in the melting of the methal hydrate ice WERE to occur within the next 50 years.My amateur guess is that the huge, albeit temporary, increase in methane over even three or four decades might push other relevent tipping points to arrive much, much, sooner than they normally would, thereby vastly incresing negative feedback mechanisms.We KNOW that quick, huge, changes occured in the Earth’s climate in the past.See other relevent posts in the past from Realclimate.Climate often does not change slowly, but undergoes huge, quick ,changes periodically, due to negative feedbacks accumulating ,and tipping the climate to a quick change.Why should the danger from huge potential methane releases be vievwed with any less trepidation?

    Mark J.Fiore

    Comment by Mark J. Fiore — 6 Mar 2010 @ 3:15 PM

  28. When I linked your post to a forum for general (not AGW) skeptics, one of the resident deniers there called it “typical warmist hysteria.”

    They never read anything past the byline, it seems.

    Thanks for the excellent summary of the recent methane news, David.

    Comment by Adam R. — 6 Mar 2010 @ 3:18 PM

  29. David,

    In your(?) book, The Long Thaw, you explained methane hydrates very well, but pictured an alarming scenario, comparable to nuclear winter or an asteroid impact, if as low as 10% of the methane hydrate were to reach the atmosphere (pages 133-136). do you still stand over that? Or are you saying that is a remote possibility only?

    [Response: Yeah, that was me. If that much methane did get out, it would be CATASTROPHIC (trying to stretch my literary range here). But it has to come out quickly, and no one has figured out how that could happen. David]

    In an earlier post (#2), I put in a wrong like .. I meant this one:

    http://climate.nasa.gov/keyIndicators/

    Would you say this has pushed the indicators for global warming deeper into the red zone. Same question I asked in #2?

    [Response: I think carbon cycle feedbacks in general kind of ratchet up the scariness of the future, yes. David]

    Great post, great site… enjoyed the book, also. Not a “rattling good read”, but concise and understandable.

    Comment by Toby — 6 Mar 2010 @ 3:41 PM

  30. On catastrophic methane degassing: Shakova and Semiletov have proposed a mechanism – the destabilisation of the permafrost cap overlying large methane hydrate deposits that contain a high proportion of free gas. The temperature regime is very different to onshore permafrost and deeper oceanic hydrates, and sensitive to warming of the shallow coastal waters over the ESAS. The new paper establishes a baseline for future measurement – but shows that their hypothesised mechanism is active (though it can’t, obviously, support a claim that it’s necessarily new). S & S have considered the potential for catastrophic release: at the very least their calls for further study need to be taken very seriously. [S&S have a chapter in last year's WWF Arctic overview , Arctic Climate Feedbacks: Global Implications (available here (pdf), which provides a very good overview of the issue].

    [Response: Not to belittle the concern, but this methane degassing would probably take place on a time scale which is longer than the methane lifetime. So it wouldn't be what I mean when I write catastrophic. It would be bad to have an increased ongoing, chronic release of methane also, and I definitely agree the region should be watched very carefully. ]

    [Side issue: David, are there any satellite products that could shed light on atmospheric methane in the area?]

    [Response: A satellite called SCIAMACHY is able to detect gas concentration plumes in the air, but I don't know whether these sorts of plumes could be seen in their data. David]

    On methane’s role in the bigger picture: Your analogy explains the primacy of CO2′s role very well, but misses what I consider to be the real danger from an active methane feedback. Release from the ESAS alone has the potential to make any CO2 mitigation efforts futile — ripping the reins from our hands, as it were. We have no sense of the size of that risk at the moment, beyond the data in the S&S paper, but we do have a rapidly warming Arctic to provide a troubling context. One to watch…

    Comment by Gareth — 6 Mar 2010 @ 3:49 PM

  31. It would be more useful to get some estimates of what the scientists involved think that the effect will be over the next 50-100 years, as was done with sea level rise.

    To get such estimates, you have to make a lot of predictions about how the biological system is going to react. For the permafrost issue, there is already retreat in the Hudson Bay area:

    The permanently frozen ground known as permafrost is retreating northward in the area around Canada’s James Bay, Reuters Feb 2010

    To track the retreat, Payette and his colleagues looked at distinctive plant-covered mounds called palsas that form naturally over ice in the soil of northern peat bogs.

    There were up to 90 percent fewer palsas in bogs around James Bay in 2005 than there were in 2004, the researchers found. And that was far fewer than those palsas shown in the area in aerial photographs taken in 1957, Payette said.

    What happens to permafrost as it melts? Do shrubs move in? Or do you get bogs, wet and full of methane-generating bacteria?

    “Arctic emissions of climate-warming methane rose 30.6 percent from 2003 to 2007, researchers reported last month in the journal Science, a suggestion that global warming could unlock huge amounts of the gas from melting permafrost.”

    It is true enough that the methane emitted would be converted to CO2 over time – but a more practical question is how these methane emissions will compare to human efforts to reduce fossil fuel emissions.

    Consider a scenario in which we work overtime to build renewable energy infrastructure, while reducing fossil fuel emissions by 50% in 2050 from 2000 levels. Now, is it possible that the natural feedback will overcome that – the methane flux, perhaps similar to the Younger Dryas methane excursion? Or is that not something to worry about?

    To answer that, we need to know what kind of rates of permafrost / shallow seabed outgassing should we expect by 2050 – and could it result in an amplification of polar amplification? What does that do to sea level rises?

    Comment by Ike Solem — 6 Mar 2010 @ 4:09 PM

  32. and why is the ch4 conzentration in the atmosphere stable over the last 10 yaers?

    Comment by Herbert — 6 Mar 2010 @ 4:31 PM

  33. I have read the sidd link in 23. It would seem that use of the 100 year factor linearizes a highly nonlinear process in a way that significantly underestimates the impact of a CH4 release on decadal time scales. Isn’t that a bit dangerous if the climate may be approaching critical tipping points? As David said, “a factor of ten increase in CH4 emission from the Arctic would be serious…” Is that an unreasonable possibility? No one really knows, I suppose, for lack of adequate information at this point. And I am sure there is considerable effort underway to try and find out.

    In the meanwhile, would it be possible to run model studies to assess a range of plausible scenarios of CH4 release, using the actual decay function for CH4, rather than a linear CO2 equivalency?

    Comment by Ron Taylor — 6 Mar 2010 @ 4:44 PM

  34. Thanks David.

    Large scale methane release, whether chronic or acute, also has implications for the OH oxidation pathway — which could mean that the atmospheric lifetime becomes extended as the OH supply is “used up”.

    The SCIAMACHY stuff is interesting, but the last visualisations I can find are from a few years ago. It would be very cool to have near real-time stuff for the ESAS (and elsewhere).

    Comment by Gareth — 6 Mar 2010 @ 5:26 PM

  35. “Most of the methane in the atmosphere comes from wetlands, natural and artificial associated with rice agriculture.” How so? The Edgar 4.0 inventory has rice
    at 33 mega tonnes and enteric fermentation at 96 mega tonnes and fugitive
    emissions from oil and gas at 72 mega tonnes. Those rice emissions have
    a side benefit … 19% of global calories … the 96 mega tonnes
    have a side benefit, about 6% of calories with most of that being milk. But
    the 96 megatonnes have plenty of extra downstream costs. Huge areas that
    could be reforested to draw down carbon are burned each year to prevent that
    happening.

    The people advocating strong methane reductions (e.g. Hansen) aren’t advocating
    switching attention away from CO2, but merely noting that our current methane forcing increments are on a par with out current CO2 forcing increments, and that we can
    reduce CH4 without diverting any resources away from the big battle … which
    is of course to leave coal in the ground. People who belittle methane
    reductions tend to think that while the planet is important, giving up
    hamburgers is too dear a price. But such people always mention the HUGE impact
    of rice.

    http://bravenewclimate.com/2010/02/04/boverty-blues-p2/

    [Response: OK, poorly worded, you're right. Livestock are a bigger source than rice farming, and the fossil fuel industry is big too. I'll defend myself by saying if you add together both types of wetlands they are the largest source, as I wrote, and I never wrote HUGE. I don't do caps. David]

    Comment by Geoff Russell — 6 Mar 2010 @ 5:39 PM

  36. Herbert, there seems to be some natural variability in addition to the direct human perturbation. As I understand it, though, there has been an uptick in recent years, and before that stabilization may have been partly due to reduced emissions of methane (including natural gas leakage) from human activity.

    Comment by OregonStream — 6 Mar 2010 @ 6:08 PM

  37. “So far no one has seen or proposed a mechanism to make that happen.”

    Here’s a patent for one: http://www.freepatentsonline.com/6209965.html. The Japanese are very interesting in hoovering up methane from the sea floor. As oil gets harder to find, coal quality continues to decline, and terrestrial natural gas sources play out, there will be a lot of people interested in hoovering up methane from the ocean.

    Comment by shargash — 6 Mar 2010 @ 6:31 PM

  38. 22. charlie says:

    2) Would extra methane near the Artic circle account for more warming there locally?

    David commented:

    2. Methane is mostly well-mixed in the air, except when they catch a plume like they did, so the warming from it is mostly global.

    Last year I posted

    I have read that

    1. Weather over Siberia can have blocking patterns with little wind.

    2. Tamino’s blog, if I remember correctly, mentioned that rises in methane levels can vary by several weeks at different measuring stations.

    3. Concentrations of methane near the emitting sources can be hundreds of times greater than background levels. Clearly, if these concentrations reached any height there would be a local warming effect. If these concentrations reached one hundred metres above the emitting sources these concentrations would occupy about one percent of the atmosphere above the source. One hundred times a background level would double the warming effect of methane in the locality.

    Warming areas where methane is emitted with methane that is not well-mixed is clearly some sort of feedback. Is it vanishingly small? I would be interested to know if anyone has done the work to dismiss it definitively.

    David is probably right. But it doesn’t sound as though he has done the work to “done the work to dismiss it definitively”. Has anyone?

    [Response: I don't think a plume of methane here or there would noticably affect the local climate any more than a cloud here or there would. Heat flows around a lot on Earth. But you're right, I haven't thought about it quantitatively. David]

    Comment by Geoff Beacon — 6 Mar 2010 @ 6:41 PM

  39. “One is that there’s no reason to fixate on methane in particular.”
    “The other thing to remember is that there’s no reason to fixate on methane hydrates in particular, as opposed to the carbon stored in peats in Arctic permafrosts for example. Peats take time to degrade but hydrate also takes time to melt, limited by heat transport. They don’t generally explode instantaneously.”

    _____
    The permafrost is likely to take many decades at least to thaw, so the methane locked within it will not be released into the atmosphere in one burst, said Stephen Sitch, a climate scientist at the Met Office’s Hadley Centre in Exeter.

    But calculations by Dr Sitch and his colleagues show that even if methane seeped from the permafrost over the next 100 years, it would add around 700m tonnes of carbon into the atmosphere each year, roughly the same amount that is released annually from the world’s wetlands and agriculture.
    http://www.guardian.co.uk/environment/2005/aug/11/science.climatechange1

    “Shakhova notes that the Earth’s geological record indicates that atmospheric methane concentrations have varied between about .3 to .4 parts per million during cold periods to .6 to .7 parts per million during warm periods. Current average methane concentrations in the Arctic average about 1.85 parts per million, the highest in 400,000 years, she said. Concentrations above the East Siberian Arctic Shelf are even higher.”
    http://climateprogress.org/2010/03/04/science-nsf-tundra-permafrost-methane-east-siberian-arctic-shelf-venting/#comments

    Why do you not mention methane highest in 400,000 years?
    Why not mention that the IPCC models not incorporate methane?

    There is a diffrence of permafrost and sea sediment methane – why not make the diffrence? Abrupt change comes – “if”, from sea sediments, irreversible thaw from the peat bog.

    Methane is the silver bullet in communicating the threat of climate change!

    Comment by prokaryote — 6 Mar 2010 @ 6:42 PM

  40. Herbert (32) — Check the Un’s FAO for statistics for estimates on area in rice production and also estimates of the number of cattle. Find someplace which estimates hectares of wetlands otherwise lost to parking lots or whatever.

    Just suggestions.

    Comment by David B. Benson — 6 Mar 2010 @ 6:52 PM

  41. Herbert, your name links to “Zentralanstalt für Meteorologie und Geodynamik.”
    What kind of organization is that? Are you a weatherman? Do you have access to current journal articles, or are you only reading old past issues?

    The information “stable over the last 10 yaers” was correct — in 2007.

    I worry about people who don’t check their facts before posting them.
    Was there some problem looking this up?

    I’m just an amateur reader, not a weather professional, and this was easy to find.

    http://www.nasa.gov/home/hqnews/2008/oct/HQ_08-276_Methane_levels.html

    — excerpt from the press release follows —-

    The amount of methane in Earth’s atmosphere shot up in 2007, bringing to an end approximately a decade in which atmospheric levels of the potent greenhouse gas were essentially stable. The new study is based on data from a worldwide NASA-funded measurement network.

    … Until recently, the leveling off of methane levels had suggested that the rate of its emission from Earth’s surface was being approximately balanced by the rate of its destruction in the atmosphere.

    However, the balance has been upset since early 2007, according to research published this week in the American Geophysical Union’s “Geophysical Research Letters.” The paper’s lead authors, Matthew Rigby and Ronald Prinn of the Massachusetts Institute of Technology, say this imbalance has resulted in several million metric tons of additional methane in the atmosphere.
    —- end excerpt—
    You can find the paper and check for subsequent cites, updates, etc. easily.

    Have a look — tell us what you think.

    Comment by Hank Roberts — 6 Mar 2010 @ 7:32 PM

  42. For Herbert, here are recent papers citing Rigby and Prinn:
    http://scholar.google.com/scholar?cites=9694380594515227158&hl=en&as_sdt=2000

    Comment by Hank Roberts — 6 Mar 2010 @ 7:35 PM

  43. Thank you for this article, I was hoping that RC would post on the topic to give context to other recent reactions.

    Revkin complains above that he is getting “reamed” when “making points like those.” His problem is that while you are putting issues into context, he is doing the opposite, and his post on the topic is a case in point. Nowhere in his article does he take on the issue that the car is travelling 70 MPH and potentially about to accelerate, instead to him it’s all about some scientists’ overreaction to a narrow slice of the whole picture. Just like his recent quibble that an IPCC summary paragraph didn’t have enough caveats to the near certainty of AGW. Blah, blah, blah, confusion and no context, a real disservice.

    Comment by The Wonderer — 6 Mar 2010 @ 8:00 PM

  44. Hi David, and thanks.

    I realise that you wrote “CO2 is plenty to be frightened of, while methane is frosting on the cake” in the context of arctic methane, but I wonder if you wouldn’t mind clarifying anthropogenic methane’s likely role in the warming thus far and into the future?

    There is a claim, promoted especially by some in the farm sector, that because methane is short-lived, and because methane levels plateaued for a short time while ruminant numbers continued to increase, efforts to reduce emissions from enteric fermentation are therefore worthless or near worthless.

    Thanks again.

    [Response: The future of methane is anybody's guess, given that the present isn't even all that easy to understand. IPCC Working Group III found lots of ways to mitigate climate change by reducing methane emissions. David]

    Comment by Corey Watts — 6 Mar 2010 @ 9:11 PM

  45. Kev #18, yes CH4 converts into C02 in the atmosphere.

    Comment by Jacob Mack — 6 Mar 2010 @ 10:24 PM

  46. The following passage is from Weart’s chapter on Rapid Climate Change.
    http://www.aip.org/history/climate/rapid.htm

    For one group of American scientists on the ice in Greenland, the “moment of truth” struck on a single day in midsummer 1992 as they analyzed a cylinder of ice, recently emerged from the drill hole, that came from the last years of the Younger Dryas. They saw an obvious change in the ice, visible within three snow layers, that is, scarcely three years! The team analyzing the ice was first excited, then sobered — their view of how climate could change had shifted irrevocably.

    This passage, more than anything else I’ve read, is what worries me about methane. We may not have yet figured out how such a rapid change was possible, but methane would seem to be the prime suspect.

    [Response: No, I don't think so. Methane does go down when the Earth cools in these so-called "abrupt climate changes", but it's not enough radiative forcing to be the fundamental driver, but rather a feedback due to drying wetlands. The abrupt climate changes were physical in origin, to do with ocean circulation and sea ice probably. David]

    Comment by Daniel C. Goodwin — 6 Mar 2010 @ 10:37 PM

  47. “CH4 + 2O2 = CO2 + 2H2O

    Direct quote:
    “So, combustion of 16 mass units (grams, pounds, whatever) of methane produces 44 mass units of carbon dioxide and 36 mass units of water while consuming 64 mass units of oxygen.”

    http://cdiac.ornl.gov/pns/faq.html

    Comment by Jacob Mack — 6 Mar 2010 @ 10:39 PM

  48. The methane venting rise and CO2 rise is tracking exactly with the other rise in multi-year ice: http://arctic-roos.org/observations/satellite-data/sea-ice/ice-area-and-extent-in-arctic

    Comment by Marilyn — 6 Mar 2010 @ 10:40 PM

  49. > methane …oxygen … CO2 … water

    But see: http://rabett.blogspot.com/2010/02/passing-gas.html

    for more than almost anyone has ever wanted to know about the details

    Comment by Hank Roberts — 6 Mar 2010 @ 11:03 PM

  50. Methane is a transient gas in the atmosphere, while CO2 essentially accumulates in the atmosphere / ocean carbon cycle, so in the end the climate forcing from the accumulating CO2 that methane oxidizes into may be as important as the transient concentration of methane itself.

    What else did you think we were worried about?

    Doh!

    [Response: Climate forcing from methane itself as a greenhouse gas, duh. David]

    Comment by ccpo — 6 Mar 2010 @ 11:19 PM

  51. Aaron Lewis says:
    6 March 2010 at 2:18 PM

    Ice and clathrates have sharp melting points…. (and other good points)

    Excellently said. This is a Seven Generations issue, not a one year wonder. Unfortunately, RC has a real blind spot when it comes to methane and rapid climate change. Yet risk analysis tells us we must prepare for the worst in this case because it equals the end of what we think of as civilization.

    The cavalier attitude towards this here at RC, both by staff and readers, is astounding. Just in the last weeks there was a paper on lake sediments that found a very large change in climate in months. Months.

    So, when we have learned over the last few years that methane is bubbling up all over the Arctic Ocean, that thermokarst lakes are tripling in size and number, that the melt of the sea ice is reflected as much as 1000 km (or was it miles?) inland, we are all just supposed to chill out?

    Let’s add to this that there is more than double the atmospheric carbon stored up in the permafrost. What’s that, then, essentially 600ppm? Ten percent of that takes us to 460 ppm. What of the sea bed methane? The paper under discussion says (rather, an article discussing it) a “fraction” of this out-gassing would cause large climate changes, right? I also know from e-mail exchanges with a scientist who has published on this issue that the temperature range for unstable clathrates is within 1 – 3 degrees for seabed methane. Unfortunately, pressure is also part of the equation, so those clathrates in Siberia are most likely near their critical threshold due to the shallow water column. And methane is rising in the atmosphere.

    Did I mention about tipping points and how a recent paper said it’s virtually impossible to know you’ve hit them until, well, you’ve hit them. (Of course, anyone who knows even a tiny bit about chaos and/or bifurcations knows this.)

    Might I suggest you could be watching the turning point and telling everyone in the theater there is no fire?

    Yeah, nothing to see here folks! Move along! Moooove along!

    Cheers

    Comment by ccpo — 6 Mar 2010 @ 11:58 PM

  52. Seems there ought to be a way to extract CH4 from the clathrates so conveniently showing us where the deposits are. Why isn’t anyone thinking about this? I think flaring gas is horribly wasteful, but it sure beats all the methane being released as a much more powerful ghg than the CO2 it’s burned into. Why don’t we place buoys with methane detectors over hot spots and flare the stuff off as it comes up?

    Can you imagine hydrocarbon extraction as a socially and environmentally responsible investment opportunity?

    Comment by Tim Jones — 7 Mar 2010 @ 12:38 AM

  53. I join with those who welcomed this as a well balanced and readable summary of some current issues. (Do I detect in these comments, perhaps, a hint that this has not always been the case at realclimate.)

    I have always felt the role of methane has been oversold. It operates over a narrow band of wavelength which it shares with nitrous oxide.
    http://www.climatedata.info/Emissions/introduction.html

    Can someone explain why we hear next to nothing on ozone as a greenhouse gas. Its absorbtion spectrum occurs near the peak of long-wave emission spectrum.

    Like Ron Taylor, I also have just read The Climate Crisis but my impression was much more negative.
    http://www.climatedata.info/Discussions/Discussions/opinions.php

    Comment by Ron — 7 Mar 2010 @ 12:49 AM

  54. Can you confirm this figure that gets bandied about…up till 400kyrs ago Ch4 levels in the atmosphere has been between 0.4 – 0.8ppm. Now today apparently it stands at 1.85ppm.
    Are these figures accurate?

    [Response: Yes. - gavin]

    Comment by Lawrence Coleman — 7 Mar 2010 @ 1:07 AM

  55. @Andy”I get reamed sometimes for making points like those in this important methane update (pushing back against some of the overheated coverage elsewhere), so this is very welcome.”

    I think part of the problem is that you work at the most prestigious and widely read newspaper in the world, with an audience that mostly does not spend as much time reading the climate blogs as you and I do. Hence, what for you is “pushing back” at overheated coverage may operate functionally rather like the high school quarterback punching a third-grader in the face. As soon as you weigh in, your counterpoint is for many people the point, and unless you present the other side of the argument effectively, your readers may be coming away with a very different idea of the conversation.

    It’d be a difficult fishbowl to work in. I think you do an excellent job.

    Comment by Robert — 7 Mar 2010 @ 2:54 AM

  56. “Unfortunately, pressure is also part of the equation, so those clathrates in Siberia are most likely near their critical threshold due to the shallow water column. And methane is rising in the atmosphere.”
    It’s not enough to say that “methane is rising”. How much is the methane of Siberia contributing to the rise, and how much does it contribute to the rise of overall forcing ? the divergence can occur only if we reach the level of retroaction loop ( ∆T/∆CH4 ) x (∆CH4 /∆T) > 1 , where the first factor measures the contribution of methane to average temperature and the second the influence of temperature on methane release. . Who is aware of a serious scientific study showing we could be any close to this thereshold ?

    Comment by Gilles — 7 Mar 2010 @ 3:24 AM

  57. Considerations

    Polar terrestrial ecosystems, permafrost, and extreme warm paleoclimate dynamics
    Here we use results from a GCM to show that Antarctica was a suitable location for massive carbon sequestration in peat and permafrost-dominated environments during the Palaeocene leading up the PETM event. Levels of assumed atmospheric CO2 and CH4 concentrations around the time of the event are shown to cross the threshold for melting vast areas of frozen soil on an unglaciated Antarctic continent, which had a subaerial surface area ~25% larger than today. This previously underappreciated potential source of carbon would have been large enough to account for a significant fraction of the total warming at the PETM once a warming threshold was reached, whereby permafrost began to melt and methane and relict soil carbon were suddenly released. If this mechanism did play a role in abrupt and extreme global warming events such as the PETM, it implies serious consequences for the thawing of similar environments in the modern boreal high latitudes.
    http://adsabs.harvard.edu/abs/2009AGUFMPP11F..03D

    Massive Methane Hydrate in Sediments to Cause the Paleocene/Eocene Thermal Maximum
    http://adsabs.harvard.edu/abs/2009AGUFMPP43B1570G

    The role of methane during the Paleocene-Eocene thermal maximum
    Moreover, proxies indicate a high background atmospheric methane concentration as well as enhanced methane production at the surface during the PETM. Modeling work has shown that an enhanced concentration of atmospheric methane can reproduce PETM latitudinal temperature profiles without invoking exceptional increases in the concentration of carbon dioxide.
    http://adsabs.harvard.edu/abs/2009AGUFMPP43B1569C

    If methane is oxidized in the oceans, this should cause an oxygen deficiency in the deep oceans and we should be able to track the release of carbon along the path of ocean circulation. Depletion of bottom-water oxygen should be widespread in the reservoir where methane oxidation occurred. Modeled sediment records from GENIE will be compared to observations from geochemical proxies of bottom-water oxygen. Redox sensitive trace metal enrichment factors in marine sediments indicate reducing conditions prior, during, and in the recovery of the PETM at intermediate depth sites in the Atlantic and Southern Ocean while the Pacific sites remain oxygenated.
    http://adsabs.harvard.edu/abs/2009AGUFMPP41A1494C

    Relative humidity across the Paleocene-Eocene Thermal Maximum via combined hydrogen-oxygen isotope paleohygrometry
    Results of the combined hydrogen-oxygen isotope paleohygrometer indicate a general rise in relative humidity during the first half of the PETM followed by a decline during the second half of the event. The rise is punctuated by at least one small drop in relative humidity. Other proxies for available soil moisture (soil weathering indices) and mean annual precipitation (leaf physiognomy) suggest an initial drying at the onset of the PETM followed by subsequent periods of wetter and dryer conditions in the southeastern Bighorn Basin. In contrast, the isotope results presented here suggest that the onset of the PETM was marked by an increase in relative humidity. This discrepancy might indicate increased seasonality during the PETM. Leaf wax hydrogen isotope values are likely biased to record primarily the growing season, which may have become more humid, while soil and plant proxies could reflect an overall decrease in available moisture as a result of increased seasonality of precipitation.
    http://adsabs.harvard.edu/abs/2009AGUFMPP11F..04M

    On the PETM and ETM2 global warming events: New evidence for a tectonic-magmatic trigger mechanism
    http://adsabs.harvard.edu/abs/2009AGUFMNH33B1144S

    Magnetofossils as Biomarkers of Environmental Change
    http://adsabs.harvard.edu/abs/2009AGUFMGP42A..04L

    Methane release from the terrestrial ecosystems of greenhouse climates: Challenges and potential
    Recent circulation and geochemical modelling suggests that atmospheric methane could have been an important driver of global temperatures during past greenhouse climates. Such conclusions are largely based on our understanding of modern wetland biogeochemistry, including the impact of hydrology, temperature and primary photosynthetic production on rates of methanogenesis

    Such values suggest that after the change in hydrology, a significant proportion of the hopanes, perhaps >50%, derived directly from methanotrophic bacteria, in marked contrast to Holocene peats.
    http://adsabs.harvard.edu/abs/2009AGUFMPP12B..03P
    ___________
    The Sun is gradually becoming more luminous (about 10% every 1 billion years), and its surface temperature is slowly rising. The Sun used to be fainter in the past, which is possibly the reason life on Earth has only existed for about 1 billion years on land. The increase in solar temperatures is such that already in about a billion years, the surface of the Earth will become too hot for liquid water to exist, ending all terrestrial life.
    http://en.wikipedia.org/wiki/Sun#Life_cycle

    Earth’s orbit is currently in a phase where the amount of sunlight falling at 65°N is changing very little.

    Despite the fact that the sun put out 0.5% less energy than today (equivalent to a global temperature that would be 0.5°C cooler), there was no polar ice cap or Greenland Ice Sheet.
    http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=1214&tstamp=&page=18

    Comment by prokaryote — 7 Mar 2010 @ 4:18 AM

  58. Interesting, thanks David.
    Is it possible to provide a link to a larger version of the figure?
    I find the text almost impossible to read – and the figure difficult to interpret – at its current size.

    [Response:
    here is the jpg, unscaled for the page.]

    Comment by Bruce Tabor — 7 Mar 2010 @ 4:23 AM

  59. #50

    Every methane molecule eventually becomes a CO2 molecule. And they be a crapload of CO2/CH4 in the permafrost (soon to become water).

    c.f. – http://en.wikipedia.org/wiki/Azolla_event

    Comment by Garrett — 7 Mar 2010 @ 5:18 AM

  60. Thought I’d share with you some recent records that have been broken weather wise here in Queensland Australia. As of from last week the central west of queensland is underwater roughly the size of the state of victoria. It has caused numerous water height records in many towns to be smashed by metres causing hundreds of millions of dollars damage. The weather systems that usually pass through the area now seem to get blocked and intense lows stay over a region for days at a time.
    Yesterday down south- Melbourne had a once in a century hailstorm that caused tens of millions of dollars damage. Hail the size of tennis balls and the city’s monthly quota of rain falling in just an hour caused wide spead flash flooding as the city’s drainage failed to cope.
    Just last year in SE queensland we had the warmest night on record.
    I have lost count of the number of extreme weather events that have ocurred last year up till now, we’re getting rather blaz’e..Oh yeah..another record..what’s new!
    The Australian climate seems to be getting much more extreme in the last few years.
    i.e. when it rains it doesn’t muck around..it simply dumps down harder and more intense than I have even seen in my 43yo life. I accept that this is the result of a hastening and intensifing hydrologic cycle but I didn’t expect the rate of change that’s evident in many parts of the world.
    If methane in the cream on the cake then I think we all better do some pretty robust dieting dont you think!

    Comment by Lawrence Coleman — 7 Mar 2010 @ 5:47 AM

  61. With the upmost respect to the climate scientists in RC. We are in uncharted waters here. No one can difinatively state that this or that will or will not happen this decade/lifetime/century…we simply do not know!
    We have 6.5 Billion little GG producing factories on this smallish planet. The faster the population rises the more nett increase there is in CO2/CH4. Compare our population now how what is was at the beginning of the industrial revolution. We now have myriads of complex industrail chemical compounds doing the rounds of the atmosphere. incl. hydro flouro carbons..probably just as deady if not more than CFC’s. We have considerably less rainforests and dense forests now than 200years ago. We have a staggering increase in the amount of cattle/pigs/sheep to feed the swarming masses..all these produce a very large ‘nett’ increase in CO2. I haven’t even begun with the burning of fossil fuels and industrisal emmissions yet..but you get the picture.
    WE are out of balance with the timeless cycles of nature in a gigantuan way!.

    [Response: The methane cycle could blow up in some unforseen way, it's true. The CO2 cycle is certainly blowing up in a totally obvious way. David]

    Comment by Lawrence Coleman — 7 Mar 2010 @ 6:18 AM

  62. #13 Mike:

    Sea ice extent is on a downward trend despite an increase since the record low in 2007. More importantly, sea ice thickness has been steadily decreasing. I use just this example in my blog post called
    Chopping Down the Cherry Tree. Please check that post out so that you do not fall into your own trap again.

    #53 Ron:

    RC threads have consistently been posted as informative pieces with no intent to alarm. My comments and those of others are more for the readers who come here having heard otherwise, especially now that scientist hunting season has begun.

    Comment by Scott A Mandia — 7 Mar 2010 @ 6:53 AM

  63. 12 SecularAnimist wrote:

    David wrote: “What’s missing from these studies themselves is evidence that the Siberian shelf degassing is new, a climate feedback, rather than simply nature-as-usual, driven by the retreat of submerged permafrost left over from the last ice age.”

    What additional science is needed in order to definitively determine whether this — and other such methane emissions that are being observed — are, in fact, new and caused by AGW, and are therefore actual AGW feedbacks; and if so, whether and how rapidly they are increasing?

    [Response: They need to figure out where the methane is coming from and why. Then wait and see how it changes with time. David]

    My guess is that some of the scientists, possibly even David, know more about the causes of the recent rise in methane – not necessarily from the causes he mentions. I bet there will be papers somewhere dragging through peer-review. The delays incurred in writing papers, compounded by the desire for papers to be watertight may be deemed good “scientific” practice but it makes it hard for those of us that care to warn policymakers – they are also frightened to be wrong. But my main criticism of David’s piece is that it can be read as don’t worry about the methane.

    Methane and the other short-lived species of climate change are important because concentrating on them for climate mitigation them has a much quicker effect and we just do not know the “unknown unknowns” of climate an we don’t know the known unknowns well enough. David’s piece may correctly point out that the Arctic methane time-bomb is not likely to explode soon (and may not be likely at all?) but he admits there is still plenty to worry about.

    My message would be “Concentrate on emissions that will slow climate change more quickly, such as methane.” For CO2 we do need to cut emissions but since there is too much in the atmosphere already we need to actively extract it. The CO2 tanker is harder to turn round than speedboat of the methane and other short lived species.

    Having read Unger et. al. “Attribution of climate forcing to economic sectors” (http://pubs.giss.nasa.gov/docs/notyet/inpress_Unger_etal.pdf), I will start flying even though I was a founder of http://www.nomileshighclub.org.uk – but beef and lamb are definitely off my menu. I may become a vegetarian again.

    Comment by Geoff Beacon — 7 Mar 2010 @ 6:58 AM

  64. G’day, seeing as how methane has risen it’s head recently I have been trying to find out how it acts as a GHG without success. Having a chemistry background, I understand how CO2 works but I’ve gotten confused by an article on Rabbitt’s blogsite that talked about GHG’s needing a dipole moment and as far as I know, methane doesn’t have one. It does, however absorb in the IR so how does that work? What am I missing here?
    Cheers, Dexter.

    [Response: Any molecule with more than two atoms will have asymmetrical vibrational modes that create transient dipole moments. David]

    Comment by Dexter — 7 Mar 2010 @ 7:53 AM

  65. @Dexter:

    CO2 has asymmetric stretch modes which are IR-active and cause absorption between 4 and 5 microns. You are correct in pointing out that the symmetric stretch mode would be only Raman-active because no change in dipole moment occurs; but that is by the by. Longer wavelength absorptions are due to bending and coupled modes.

    CH4 has numerous asymmetric bending and stretching modes and some torsional modes as well, so there is no shortage of ways to absorb IR.

    Comment by Snowfire — 7 Mar 2010 @ 9:08 AM

  66. Very interesting article, thank you for putting methane fluxes in perspective relative to the carbon dioxide problem.

    Speaking of methane hydrates . . . . more potentially bad news. China is apparently going after vast, recently discovered (September 2009), reserves (strangely characterized as “combustible ice”) in Qinghai Province:
    http://news.xinhuanet.com/english2010/china/2010-03/06/c_13200033.htm

    The Xinhua News Agency says there are 90 years worth of China’s energy needs in these reserves. Our problem is that these “fossil” energy reserves are too “easy” to get at compared with cleaner alternatives – and there are too many of them in countries that are rapidly developing. Realistically, might the extraction and combustion of methane hydrates be more of a “game changer” than the gradual increase in the release of methane from these deposits that is (or might be) occurring due to climate change?

    Comment by Tom Huntington — 7 Mar 2010 @ 10:23 AM

  67. “For methane to be a game-changer in the future of earth’s climate, it would have to degas to the atmosphere catastrophically, on a timescale that is faster than the decadal lifetime of methane in the air. So far no one has proposed a mechanism to make that happen.”

    Yes they have. It’s called higher temperatures in the Arctic, the factor that according to both Shakova’s and Walter’s measurements has accelerated methane releases. The reason is CO2 driven warming causing melting of permafrost on land, and perforation of ocean permafrost due to higher temperatures in the East Siberian Arctic Shelf.

    [Response: But it takes a very long time to melt permafrost or warm up the deep ocean where the hydrates are, let alone the deep sediment column. No one has figured out how it could explode on a time scale of a few years. David]

    Your Toyota with the brake problem and the stuck accelerator is an irrelevant analogy. Of course the increased CO2 is where we should focus, since methane is a feedback, and a potential endgame. Unfortunately, thanks to the oil and coal companies, we are doing little about slowing CO2, in case you haven’t noticed.

    I think that you and a few other climate scientists have been intimidated by the deniers, for two reasons: Solid research, including the recent paper from Shakova and NSF, is criticized polemically, not with better data or hyphotheses.

    [Response: I didn't criticize anything or anyone. I merely pointed out where the questions are. ]

    The second reason is more telling: you seem to have forgotten that any reasonable planning must include plausible catastrophe scenarios. I personally know scientists who predict something approaching ruin, based on their understanding of the data. Apparently, many scientists seem to have collectively decided that the Venus scenario is taboo, since if it doesn’t happen (after we’re all dead anyway) they might look foolish for predicting it.

    As I told Revkin, you all need to study Wietzman’s paper, game theory, quantum theory, and why planners in any field assign high values- and aggressive countermeasures- to the ruin scenario. Even if this probability is less than 10%- though my reading of the evidence points a whole lot higher than that.

    I don’t know why some of you seem to now be afraid to even mention possible apocalyptic paths. Are you afraid of being mocked by Anthony Watts or Glen Beck?

    Comment by mike roddy — 7 Mar 2010 @ 10:35 AM

  68. David, I hope that at some point you will respond to Ron’s criticism of your book on his website (comment 53). I don’t agree with him, especially re Fig 3.1, but would rather hear your take. It’s OT here, I guess, but I think it is important.

    [Response: I don't think I like being called a politically motivated "warmist". I think I'm by nature a pretty honest person, and I certainly wouldn't gain anything in reputation (and what else does a scientist have?) by biasing the science in one direction or another. I think Ron on comment #53 can write his own damn book, if he's so much better than we are, since you asked. David]

    Comment by Ron Taylor — 7 Mar 2010 @ 10:54 AM

  69. Don’t agree, we have a lot of methane getting released now, and the atmospheric concentration is constantly raising. If Earth is a unstable system, that means non linear, we can get a tipping from it. Then it won’t matter a bit that it’s a more ‘transient gas’, or however you now want to express it. That it also oxidize into CO2 under its cycle is just a ‘icing on the cake’. We need some real research done in the arctic, tundra etc, and also a better model of how much methane that really is released.

    Comment by Yoron — 7 Mar 2010 @ 11:38 AM

  70. Tom Huntington,

    “Russia is creating a new high-tech industry. We develop methane, which is the enemy of coal miners, into a business that can be efficiently used to satisfy growing global demand for energy resources.”
    http://rt.com/Business/2010-02-12/medvedev-unveils-energy-plan.html

    Unconventional gas deposits such as shale gas, coal-bed methane and tight gas helped make the U.S. the world’s biggest producer of the fuel and could reduce Europe’s reliance on pipeline supplies from Russia and Norway. Exxon, Royal Dutch Shell Plc and BP Plc are among companies that plan to explore unconventional sources in Europe.
    http://www.businessweek.com/news/2010-03-02/exxon-says-early-days-for-european-alternative-gas-projects.html

    Ice on fire: The next fossil fuel
    DEEP in the Arctic Circle, in the Messoyakha gas field of western Siberia, lies a mystery. Back in 1970, Russian engineers began pumping natural gas from beneath the permafrost and piping it east across the tundra to the Norilsk metal smelter, the biggest industrial enterprise in the Arctic.

    By the late 70s, they were on the brink of winding down the operation. According to their surveys, they had sapped nearly all the methane from the deposit. But despite their estimates, the gas just kept on coming. The field continues to power Norilsk today.

    Where is this methane coming from? The Soviet geologists initially thought it was leaking from another deposit hidden beneath the first. But their experiments revealed the opposite – the mystery methane is seeping into the well from the icy permafrost above.
    http://www.newscientist.com/article/mg20227141.100-ice-on-fire-the-next-fossil-fuel.html

    Comment by prokaryote — 7 Mar 2010 @ 11:41 AM

  71. The great unknown would be Arctic ocean water temperature at the interface between arctic ocean bottom with frozen methane hydrates. I have heard also from a direct source, under water camera man, that its bubbling greater than before near the Mackensy delta, but what would be the theoretical temperature increase to make it outgas a whole lot more? Arctic sea water surface temps are increasing, but there is a huge difference between the bottom and the top.

    Comment by wayne davidson — 7 Mar 2010 @ 11:48 AM

  72. * “Imagine you are in a Toyota on the highway at 60 miles per hour approaching stopped traffic, and you find that the brake pedal is broken. ”

    This metaphor is perfect for climate change, resource depletion, peak oil, overpopulation and the crumbling of infrastructure which represents the accelerating trends leading to the collapse and cessation of technological civilization.

    It is also am excellent metaphor for the capitalist ponzi scheme which is forced to generate ever greater bubbles in order to propel the economy forward along an irrational, unsustainable, doomed to collapse path.

    Ironically, I was thinking of using just such a metaphor in order to write a “Letter to the Editor” to the local newspaper, deciding against it though since there is a certain futility to all efforts at warning humankind about the consequences of our present lifestyle and the tragic end which humankind has chosen for itself.

    Instead, I watched a glorious sunrise this morning and spent time with the shore birds. This world is too beautiful to leave in human hands. That much is certain. A planet such as the Earth should never have fallen into human hands.

    [Response: Great choice. But write the letter anyway.--Jim]

    Comment by David Mathews — 7 Mar 2010 @ 11:59 AM

  73. “OK, so damage probably doesn’t scale linearly with velocity.”

    Lethality varies with delta V^4. So 90mph –> 0mph is five times more likely to kill you than 60mph –> 0mph. (Changing the example from 60mph to 70mph makes the crash four times more lethal instead of five times more lethal.See the DOT report here: http://www.tfhrc.gov/safety/speed/speed.htm.)

    I get what you’re saying, but your analogy makes the opposite point: when you are headed for a high-speed collision, even a slight acceleration is quite dangerous and worrisome.

    Comment by Robert — 7 Mar 2010 @ 12:04 PM

  74. Mike Strong (13) wrote:
    “We are shivering all this winter, all over the northern hemisphere with the blizzards, the record snow, record cold, snow in ALL fifty states for the first time that we know of…oh geez!”

    Really? That’s strange, because I live in Washington state at latitude 48.11 (I think that meets the criteria for northern hemisphere) and we’ve just enjoyed the warmest January-February on record. I’ve been running outside in shorts and tee-shirt most days and I do NOT run in the snow. Maybe you should recheck your information sources, because you are clearly mistaken.

    Comment by Ken W — 7 Mar 2010 @ 12:09 PM

  75. David

    Thank you. From someone with both a great interest in the topic and the poor owner of a Toyota.

    What is missing here is a mention of the link (if any), between this observed methane and that one particular source, clathrates. At first, this seems to be a post about a paper about methane, but paragraph 3 has an incongruous link to methane hydrates. What would you say about this link? Is it important to find out the source of the methane?

    Perhaps one way to tell would be to see via modeling how a recent atmospheric-warming-driven temperature pulse would compare to a post-glacial/sea-level rise/shelf inundation pulse. And then whether one or both of those are sufficient to have perturbed T at the top of the clathrate stability zone in this area?

    [Response: That's kind of where the Westbrook and Reagan papers fit in, but I agree it's not at all clear how much methane is coming from hydrates. David]

    Comment by Dennis Denuto — 7 Mar 2010 @ 12:28 PM

  76. > http://www.google.com/search?q=snow+in+ALL+fifty+states
    http://www.npr.org/blogs/thetwo-way/2010/02/50_states_snow_florida.html
    Florida was the holdout, on that one day, and they got a sprinkling.

    Snow falls at high elevations in Hawaii routinely. Volcanic peaks, duh. The total snow documented in Hawaii was “about the size of a kitchen table”
    Story: http://newsok.com/ou-student-found-snow-in-50-states/article/3440383
    Photos: http://www.patricktmarsh.com/snow-shot-of-america/

    Mike Strong: this does not mean what you are thinking it means.
    Look at the temperature in the Arctic
    http://arctic.atmos.uiuc.edu/
    (don’t believe the story you find at WTF)
    and ask why the cold air went south.

    Comment by Hank Roberts — 7 Mar 2010 @ 12:33 PM

  77. Ken W says:

    Really? That’s strange, because I live in Washington state at latitude 48.11 (I think that meets the criteria for northern hemisphere) and we’ve just enjoyed the warmest January-February on record. I’ve been running outside in shorts and tee-shirt most days and I do NOT run in the snow. Maybe you should recheck your information sources, because you are clearly mistaken.

    I live in Portland, OR and of course it’s been the same here.

    It’s coming to an end, though, we’re going to have a week of colder weather. Never mind that it won’t be *exceptionally* cold for this time of year, but I expect a week full of denialbot screaming “look how cold it is in the PNW!”, ignoring the exceptionally warm winter we’ve had overall.

    Wanna bet Watts posts on it?

    Comment by dhogaza — 7 Mar 2010 @ 12:38 PM

  78. Wayne Davidson,
    what would be the theoretical temperature increase to make it outgas a whole lot more? Arctic sea water surface temps are increasing, but there is a huge difference between the bottom and the top.

    Gas hydrates, El Niño, and global change: A case study

    December 8, 1997

    SAN FRANCISCO, CA —On the seafloor off Northern California researchers have found evidence that deposits of methane hydrate—the ice-like, solid form of the greenhouse gas, methane—are poised in a delicate balance that could shift with even small increases in ocean temperatures, possibly unleashing a cascade of environmental effects.

    Peter Brewer and colleagues from MBARI, the U.S. Geological Survey, the National Oceanic and Atmospheric Administration/Pacific Marine Environmental Lab, and Stanford University used MBARI’s remotely operated vehicle (ROV) last August to investigate a site about 25 km (15 miles) off shore, where other scientists had earlier documented the presence of gas hydrate. The MBARI researchers found the site, located at a depth of 521 meters (1,700 feet) in the Eel River Basin, populated with vesicomyid clams and bacterial mats—all of which depend on methane and hydrogen sulfide vented from beneath the seafloor. They also saw extensive slabs of calcium carbonate, formed by bacterial action on methane. However, while the team observed, via an underwater video camera, a methane seep pumping out about 200 liters of gas per minute (STP), they found no solid gas hydrate either at the seafloor or in cores of sediments the ROV extracted at the site.

    Temperature readings and other measurements made in the water surrounding the site indicated that conditions had changed there since the methane hydrate was discovered in 1987. Many gases react with water and convert to solid hydrates, but only at precise combinations of pressure and temperature. “This year,” Brewer said, “with the northward transport of enormous volumes of warm water due to El Niño, the water temperature at the depths where hydrates would occur is about a degree warmer than it was in 1987.” The temperature increase depresses the threshold at which hydrate converts to gas and vice versa; thus Brewer and his team found bubbling gas at 521 meters, instead of solid hydrate.
    http://www.mbari.org/news/news_releases/1997/dec08_brewer.html

    >>> Read the complete article on Ice on Fire.

    Exploitation of clathrate reserves might exacerbate this problem, but it could also have far more immediate adverse effects. Clathrates exist in a delicate balance, and the worry is that as gas is extracted its pressure will break up neighbouring clathrate crystals. The result could be an uncontrollable chain reaction – a “methane burp” that could cascade through undersea reserves, triggering landslips and even tsunamis.
    http://www.newscientist.com/article/mg20227141.100-ice-on-fire-the-next-fossil-fuel.html?page=2

    Comment by prokaryote — 7 Mar 2010 @ 12:39 PM

  79. Should we be worried about the methane issue? Of course we should have already been plenty worried about CO2 and should have since 1990 reduced our GHG emissions by at least 50%, just based on the CO2 worry.

    But since most people have not been worried over the past 20 years, this is as good a time as ever to start worrying and take action.

    There is also the issue of maybe a crash at 60 mph doesn’t kill the person, but at 90 mph it does. There are straws that break the camel’s back. We should worry about the total load, and also those straws.

    For instance, with only the CO2 and methane lagging well behind, perhaps just perhaps we could have avoided the venus syndrom and runaway warming ending all life on planet earth, and only faced maybe 75% extinction of life on earth. Perhaps the sooner than expected methane outgassing is the straw that breaks that limping, half-dead camels back for us, and kills it completely. Time will tell…..

    So for those not as yet worried, this is the time to jump on the bandwagon and mitigate like heck. Just try it. You’ll like it.

    [Response: Hey Lynn, the last iteration of your screenplay that you showed me had just these same methane plumes in the Arctic, as your harbingers of climate doom and intrigue. Can't wait for the rest of your scenario to play out! David]

    Comment by Lynn Vincentnathan — 7 Mar 2010 @ 12:41 PM

  80. For Mike Strong:
    http://www.skepticalscience.com/Does-record-snowfall-disprove-global-warming.html

    Comment by Hank Roberts — 7 Mar 2010 @ 12:57 PM

  81. With regard to your analogy … I see a better analogy as the Toyota hurtling not towards stopped traffic, but towards the edge of a cliff, for two reasons.

    First, the cliff analogy includes the phenomenon of overshoot.

    We aren’t going to come to an abrupt halt when we hit some “wall” — we will go shooting off the precipice, and our momentum will keep us going for a while, like the Coyote with his legs frantically windmilling in the air for a moment before the plunge, in the old Roadrunner cartoons. Those who prefer not to look out the windows of the Toyota can imagine, for a while, that we are still merrily sailing along. And in fact, we may very well be in overshoot, right now.

    Second, once we have overshot the precipice, what happens to us when we drop?

    Well, it depends on the terrain below. It may be a relatively gentle slope to the bottom, perhaps cushioned by vegetation and branches to break our fall, and we will tumble down to the bottom, where we will emerge from our wrecked Toyota, bruised and battered but still able to limp away from the crash.

    Or, the cliff may be a thousand-foot sheer drop. And we don’t know for sure which one it will be, because we can’t see over the cliff.

    And of course, if you go over the cliff and it IS a thousand-foot sheer drop, then it makes little difference whether you were going 70 or 90 MPH when you went over the edge, does it?

    Comment by SecularAnimist — 7 Mar 2010 @ 1:36 PM

  82. Hank # 49 good link. I always enjoy reading Rabbet’s site. He is one of the few on the web with solid knowledge of P-Chem.

    I still think we should be concered about methane as a long term detriment to climate through its conversions.

    Comment by Jacob Mack — 7 Mar 2010 @ 2:17 PM

  83. Similar to Rabbet’s post with some details on isotopic detection and more references:

    http://www.iop.org/EJ/article/1755-1315/6/28/282017/ees9_6_282017.pdf?request-id=ce994d16-76ae-4749-9536-4e75d3f06021

    Comment by Jacob Mack — 7 Mar 2010 @ 3:43 PM

  84. Oh my, why would you encourage David Matthews to write their letter to the editor?

    [Response: As an antidote to a sense of hopelessness, which grows like cancer, among others.--Jim]

    What on earth does resource depletion, peak oil, overpopulation and crumbling infrastructure have to do with what this website is supposed to be about? Pretty off topic I would say (although entirely your prerogative). Just because we’re addicted to oil, people are having babies and pipelines are corroding doesn’t convince anyone (save for greenpeace) that AGW is happening.
    Matthews post is quite typical of those that despise the capitalistic ‘ponzi scheme’.The irony is that capitalism is the tool that will get us out this mess.

    [Response: Adjusting the earth's atmospheric composition so that it's radiative flux is minimally disruptive for human society and the natural world is what will get us out of this mess. How that is best done is a complex, but separate, question.--Jim]

    One wonders if he’d have the luxury of spending time with the shore birds in the morning if he didn’t live in a world built by capitalistic forces.
    An individual who has lost hope in humanity, or probably never had hope to begin with is not the best spokesman for the AGW cause.
    My hope is that none of you on Real Climate share this person’s perception of reality.
    Thanks

    Comment by Sean — 7 Mar 2010 @ 4:22 PM

  85. I don’t understand something, David. If CO2 is driving temperatures up in an accelerating curve and if increased temperatures are melting the permafrost and warming the oceans and if melting permafrost and warmer oceans lead to more methane release and if more methane in the atmosphere increases the greenhouse effect and further raises temperature, how is this not a positive feedback loop with catastrophic consequences? Won’t warmer temperatures release more methane further raising temperatures and releasing even greater amounts of methane in an accelerating feedback loop? You say that the methane is ‘transient’ but doesn’t it decay into CO2 among other things? Isn’t there more fossil carbon in these methane hydrates and locked under the permafrost than in all of the other fossil fuels both already burned and still in the ground? Isn’t the mechanism whereby this methane gets released in vast quantities simply the increasing temperatures of the atmosphere and ocean, particularly in the polar regions? Please help me understand this better.

    [Response: You understand things fine I think. But the positive feedback with methane is iffy and speculative. What if it doesn't turn out to be important? Don't want people to then think, ok, everything is fine. The accelerator pedal suddenly starts working again, great, but the brake pedal is still broken. My concern for future climate would not go away in that case. David]

    Comment by Ghonadz — 7 Mar 2010 @ 4:35 PM

  86. Prokaryote quoted at #78–”Clathrates exist in a delicate balance, and the worry is that as gas is extracted its pressure will break up neighbouring clathrate crystals. The result could be an uncontrollable chain reaction – a “methane burp” that could cascade through undersea reserves, triggering landslips and even tsunamis.”

    This is what I have read, too, about possible triggers for large-scale, sudden releases of methane hydrate. I believe there was at least one well documented instance in the North Atlantic. If anyone can track it down, that might be illuminating.

    I would like to add to CCCP’s (and others’) point (#51) about the generally much warmer Arctic sea surface temperatures, that with rapidly falling sea ice cover, there is much more wave activity from wind hitting now-open ocean. This increases the amount of surface to bottom interaction, especially in the vast areas off northern Asia where the continental shelf is just a few meters below the surface.

    I don’t see how anyone can so glibly dismiss the possibility of catastrophic release.

    Of course, even if this weren’t a factor, David has kindly pointed out in his response to #46 that sea ice and ocean current changes are more likely to be the immediate cause of rapid, catastrophic global climate change, and these. Fortunately there has been no evidence of rapid changes in sea ice or ocean currents in the last few years…or, wait…oops.

    I think the thoughtful hosts of this excellent site are bending over backward to defuse alarm about this because, 1) indeed not completely certain how it will play out and may well end up being just a bit player in the big scheme of things; but also 2) it is something that, once started, no one can really do anything about, and that could lead to counterproductive despair and resignation (I must admit to feeling some of that upon hearing about this paper, even though I had heard a lot about the research leading up to it, and earlier papers saying similar things–somehow seeing it in “Science” gives it a whole new level of psychological reality); and perhaps 3) here was a chance for them to sound distinctly non-alarmist, in the face of what might be viewed as alarm in MSM and in other blogs.

    While I am sympathetic to both motivations, I think we are best served by the clearest understanding of the potential gravity of all risks. If a situation is alarming, why shouldn’t we be alarmed, even if other parts of the big picture remain equally or even more dangerous and alarming?

    [Response: But it takes centuries for warmth to get down where the hydrates are, so the methane would come out in small burps, essentially like an ongoing chronic emission, rather than all at once. Even a giant landslide wouldn't release enough methane to really affect the climate in a catastrophic way. Don't mean to be glib, just sayin'. David]

    Comment by wili — 7 Mar 2010 @ 5:22 PM

  87. > I still think we should be concered about methane
    As are we all.

    The air temperatures have been _cold_ over on the Siberian side recently.
    But I don’t know if sea water, especially bottom water, temps. are related to the local air temp or if that water comes in from elsewhere. Anyone got a circulation map? If we could check the temps. of the water that _will_ be passing over that shallow methane source maybe we could predict the future emission rate. (Anyone have ocean temps handy, or a reference on how long it takes a change in sea-bottom water temp. to propagate down into the sediment where the methane comes up?)

    I suspect the people with expertise in drilling for natural gas must have a lot of information on this sort of thing that they aren’t mining-so-to-speak for climate papers, just because they’ve been collecting information for a long while all over the area. Proprietary — but perhaps they could edit out the locations and publish something in the way of forecasting where there will be warmth reaching the mud enough to release the gas.

    Anybody got 20,000 square kilometers of polyethylene sheeting handy that could be sunk over the area to collect bubbles?

    Oh, wait, there are fisheries there too, what’s left of them. Dang.

    And so it goes:

    http://www.arctic.noaa.gov/reportcard/figures/seaice2009fig2-sml.jpg

    Comment by Hank Roberts — 7 Mar 2010 @ 6:03 PM

  88. Methane is a transient gas in the atmosphere, while CO2 essentially accumulates in the atmosphere / ocean carbon cycle, so in the end the climate forcing from the accumulating CO2 that methane oxidizes into may be as important as the transient concentration of methane itself.

    What else did you think we were worried about?

    Doh!

    [Response: Climate forcing from methane itself as a greenhouse gas, duh. David]

    Comment by ccpo — 6 March 2010 @ 11:19 PM

    David,

    While the short term potential damage from methane is a real concern, and might be particularly for very short terms by warming ice in those areas where the emissions just above and below the water line (possibly?), we all pretty much know the long term effects are the thing.

    Context is everything. The context make it clear the concern is long term.

    Cheers

    Comment by ccpo — 7 Mar 2010 @ 6:06 PM

  89. From Co2 to methane, then what?

    Water Vapour, 40,000 parts per million.
    CO2, 360 parts per million
    Methane, 1.7 parts per million

    Comment by Jimbo — 7 Mar 2010 @ 6:25 PM

  90. “Unfortunately, pressure is also part of the equation, so those clathrates in Siberia are most likely near their critical threshold due to the shallow water column. And methane is rising in the atmosphere.”
    It’s not enough to say that “methane is rising”. How much is the methane of Siberia contributing to the rise, and how much does it contribute to the rise of overall forcing ? the divergence can occur only if we reach the level of retroaction loop ( ∆T/∆CH4 ) x (∆CH4 /∆T) > 1 , where the first factor measures the contribution of methane to average temperature and the second the influence of temperature on methane release. . Who is aware of a serious scientific study showing we could be any close to this thereshold ?

    Comment by Gilles — 7 March 2010 @ 3:24 AM

    In terms of scientific understanding, you are correct. In terms of “knowing” and policy, I disagree.

    Perfect example? As I have said before, when Katey Walter first published on the thermokarst lakes, which was after we learned of the renewed rise in atmospheric methane, I told all and sundry they should expect that rise to continue and for more methane coming from the seabed and land to be found. Heck, there was even some question as to whether the seabed emissions found in the last couple years were hydrates. I knew they were. Not scientific, but it didn’t need to be.

    It was easy to predict the continued rise and that we would find more and more because…. wait for it… the earth and it’s air and seas are all warming. Massive surprise, I’m sure.

    The point I am making is that the Ivory Tower is a great place for scientists to study in, but a poor place for them to be influencing policy and public perception. Throughout history great advances have come from great leaps of intuitive knowledge. Somehow in this era we have chosen to pretend science can only, should only, advance by knowledge alone and leave intuition and insight out of the equation.

    This way of thinking is a death knell wrt climate. By the time anything gets proven climate is another two steps ahead.

    I said two years ago methane was a serious problem and that downplaying it could prove our undoing. Now, everything I feared is confirmed and the scale can, and will, only get bigger. This is a promise. Is it scientific? No. But it is fully logical within the context of warming –> methane –> warming –> methane… Speed of change is the only issue. Given possible speed of large changes in climate is now down to months, downplaying methane as a factor is akin to bringing a stick to a sword fight; you might turn out alright, but the odds are very, very long.

    Cheers

    Comment by ccpo — 7 Mar 2010 @ 6:26 PM

  91. For those who want to spend trillions shaving a small percentage of a trace gas called Co2 from the atmosphere then please see what a trillion dollars looks like.

    http://www.pagetutor.com/trillion/index.html

    Comment by Jimbo — 7 Mar 2010 @ 6:39 PM

  92. As I told Revkin, you all need to study Wietzman’s paper, game theory, quantum theory, and why planners in any field assign high values- and aggressive countermeasures- to the ruin scenario. Even if this probability is less than 10%- though my reading of the evidence points a whole lot higher than that.

    I don’t know why some of you seem to now be afraid to even mention possible apocalyptic paths. Are you afraid of being mocked by Anthony Watts or Glen Beck?

    Comment by mike roddy — 7 March 2010 @ 10:35 AM

    Very nicely stated (the whole comment.) I did not see this when I responded. Since mine is not up yet, perhaps the staff noticed.

    Still: EXACTLY the way we need to be thinking. The science is not the solution, it’s the data. The solution lies in risk management. So, RC dudes, please don’t minimize the threats. That’s not your job. That’s ours to decide. That is, the body politic.

    [Response: Oh is that a fact? David's one of the world's leading researchers on the carbon cycle, but discussing the relevance of this paper's implications (and others', recently) is not his job eh? OK then.--Jim]

    Unless, of course, you want to go all Hansen on us and roll up your sleeves and really get into the fight. If so, the point is all the more important: the public must come to understand risk assessment and why we must act.

    Put another way, if you’re not ringing the alarm, your kind of part of the problem.

    [Response: Try to get something straight. The assignment of scientists is not to ring bells, nor is it necessarily to refrain therefrom. The job of scientists is to give the best possible description of what is happening and why, especially in an issue as contentious as this, where everybody and their brother has their own axe to grind. This should be obvious--Jim]

    Cheers

    Comment by ccpo — 7 Mar 2010 @ 6:41 PM

  93. David,

    I think your acceleration analogy conflated the two climate forcings of carbon dioxide and methane in a way that misleads and confuses. Anthropogenic carbon dioxide is a forcing that, ostensibly, humanity both creates and can control the creation of. Arctic methane, on the other hand, once that fuse to the methane time bomb is lit, has a mind of its own (dictated by methanogenesis in wetland, and, in terrestrial and subsea permafrost—by the destabilization or thawing of methane hydrates). As such, wouldn’t the methane time bomb, once detonated, be like a another truck ramming the car in the rear and accelerate it into the stopped truck, even if the car’s engine is turned off? . . . Or, like this analogy: http://climateprogress.org/2010/03/04/science-nsf-tundra-permafrost-methane-east-siberian-arctic-shelf-venting/#comment-265877

    Comment by Greg Robie — 7 Mar 2010 @ 7:39 PM

  94. Like Lynn, I have what I call the methane time bomb in my latest novel. It’s just one symptom with CO2 the main culprit. I show methane releases as a mainland issue rather than offshore. There’s plenty to worry about indeed.

    Comment by Mark A. York — 7 Mar 2010 @ 8:13 PM

  95. David

    Thanks for the response… actually, the Westbrook and Reagan papers deal with the Svalbard setting, which is more or less typical oceanic (albeit high latitude) gas hydrates. It is not of the (relic) permafrost-associated, submerged shelf type, with all those attendant issues of entrained organic matter, lithology, etc. etc. So those have had only the ocean-bottom warming perturbation, not the potentially more “severe” thermal perturbation associated with the post-glacial shelf transgression, so it is perhaps not such a great analogue?

    [Response: Katey Walter in Fairbanks has published observations of methane coming out of permafrost in rings around lakes, from the boundary of the "thaw bulb" around the lake, and she thinks that the methane in the Siberian shelf could be from the same mechanism. But it's not clear whether the methane comes from hydrates or peat, nor is it obvious to me why it would matter which the source is. David]

    Comment by Dennis Denuto — 7 Mar 2010 @ 8:13 PM

  96. Lawrence @60 does have an interesting point, about slow moving storms -and new ones following the same track. This was certainly happening over North America this winter, especially over the eastern seaboard. Maybe we could have a future post about the distribution of extreme weather events. The standard explanation for the apparent increase in extreme precipiation events, that we have roughly 4% more water vapour in the atmosphere, doesn’t expalin the fact that the high precipitation event tail seems to be increasing. So there must(may) be something going on that favors atmospheric circulation patterns that either/or slow storm systems or allow trains of similar storms to hit the ame area. That this could be a result of warming is not at all intuitive!

    Comment by Thomas — 7 Mar 2010 @ 8:15 PM

  97. I was just reading about Messoyakha, the gas field mentioned by prokaryote in #78. It’s an anomaly and has a low production volume in any case. No economical method of extracting hydrate has ever been developed, and likely never will, with onshore unconventional sources of natural gas dominating new resource extraction.

    Peak oil researcher Jean Laherrère published an excellent piece for theoildrum.com on hydrates. He mentions Milkov’s study Global estimates of hydrate-bound gas in marine sediments: how much is really out there?, which shows that estimates have decreased by an order of magnitude since the 1970s; yet these earlier figures are still bandied about all too often.

    What is the state of the science with regard to methane paleoclimate proxies? Has recent work increased the resolution for pre-Pleistocene measurements?

    [Response: Milkov's estimates are an order of magnitude lower, but maybe he's wrong, explaining the ongoing bandiment. The uncertainty hasn't really diminished much over the years; everyone agrees on the area of the sea floor containing hydrate, because you can see bubbles seismically, but the uncertainty is the amount of methane per square meter. David]

    Comment by KLR — 7 Mar 2010 @ 8:45 PM

  98. RE #79, Hi David. I had to give up screenwriting for now & concentrate on academic pubs — my recent one “Food Rights & Climate Change.” I’m also developing an interdisciplinary Environmental Studies Program at my U.

    However, there was a pretty good UK miniseries, BURN UP! (see http://www.imdb.com/title/tt1105836/ ), that had a scene in it where they are out on Arctic ice, they drill a hole down to the ocean, then light a match above it, and it flares way up. I don’t know if this is realistic or not.

    [Response: Check this out. From Katey Walter. Don't forget to say "whoa!". David]

    I did write another, better one in which a guy time travels from the future dying world to our time. I called it HYSTERESIS, but after reading Hansen’s 2008 Bjerknes Lecture, I think I’ll call it, THE VENUS SYNDROME. But no time now to fix it up…

    Comment by Lynn Vincentnathan — 7 Mar 2010 @ 9:16 PM

  99. In one of the peak oil books I recall reading how big oil gave up on mining methane hydrates (aka clathrates) and one of the reasons for abonding the project is the high risk for ships above the area. If the methane broke free quickly, it would reduce the buoyancy of a ship potentially causing it to sink abruptly. The Bermuda Triangle’s reputation for losing ships is thought by some to be related to this effect, but more it’s more likely that this reputation is a myth (and anyway the accompanying probably bogus reputation for losing an unusually high number of aircraft in the area couldn’t have the same cause).

    As to whether using methane as a fuel is somehow good, it’s a lower-pollution option than most other fossil fuels and if it is going to be vented anyway it’s better if we burn it usefully. But if it is contained somewhere like under permafrost or in the oceans, it would be far better to leave it where it is (especially considering what it takes to cause it to vent out).

    [Response: Hydrate methane is now considered mineable in the right conditions. They destabilize it by injecting warm water or chemicals. Mostly this is from gas reservoirs on land. This may supply ~10% of methane production in the next decade or so. See Gas Hydrate Resource: Smaller But Sooner , By: Kerr, Richard A., Normile, Dennis, Science, 0036-
    8075, February 13, 2004, Vol. 303, Issue 5660. David]

    Comment by Philip Machanick — 7 Mar 2010 @ 9:19 PM

  100. Gavin,

    [Response: Not. This was written by David. Attention to detail appears not to be your strength]

    Good post. You need to do more of this. Present the science and drop the agenda.

    [Response: Clarifying the science is the agenda.--Jim]

    We would all be better off. Maybe you are heeding Judith Curry?

    [Response: Hardly. --Jim]

    I hope so.

    Cheers,

    Walt

    Comment by Walt — 7 Mar 2010 @ 10:33 PM

  101. Jim,

    Clarifying the science has been the agenda on this site? [Hardly-Walt]

    Agenda science, pseudo-science, silly science, semi-science and just plain nonsense science has been the hallmark of this site for so long that it was refreshing to see see some modicum of non fear-mongering here. I thought cooler heads were prevailing.

    [Response: The fact is, like many, you don't even have the scientific background to make such grand general assertions of incompetence. But that never stops y'all from passing 'em around the internet anyway, as if you're some kind of experts. As for non fear-mongering, look at the last two science posts, among many others.--Jim]

    Cheers,

    Walt

    Comment by Walt — 8 Mar 2010 @ 12:12 AM

  102. Wili
    2) it is something that, once started, no one can really do anything about
    Yes, we can do something about it.

    Transform from carbon positive technology to negative – sustainable.
    Biochar production globaly on industrial scale to remove carbon from the atmosphere.
    Reforestation everywhere – sustain and create natural carbon sinks.
    Energy efficiency, energy diversity, energy security(Fossil energy is not save!).
    Switch to clean energy solution and start clean up the environment, immediately.

    Comment by prokaryote — 8 Mar 2010 @ 12:12 AM

  103. Thanks for the correction, prokaryote. I have said much the same thing on other sites, and I didn’t mean to sound as if I were advocating do-nothing-ism (although much of what we have to ‘do’ is to STOP doing things that require burning fossil fuels.) It’s just that feedback loops have a kind of life-of-their-own quality that makes them seem different than direct anthropogenic emissions. The take home message is that we have to reduce our emissions and draw down atmospheric levels of GHG even faster now given these (and other) new forcings.

    To Greg at #93 who wrote: “I think your acceleration analogy conflated the two climate forcings of carbon dioxide and methane in a way that misleads and confuses. Anthropogenic carbon dioxide is a forcing that, ostensibly, humanity both creates and can control the creation of.”

    Well put, by I would go one step further and point out that the Toyota analogy is exactly backwards:

    Anthropogenic CO2 (and other anthropogenic GHGs) are our collective foot on the gas pedal, a forcing that in principle we could remove at any time (though, yes, removing our contributions would not immediately bring down temps).

    Clathrates represent a new forcing outside of our immediate control, so it is more like the brake giving out as WELL as the accelerator adding more gas at the same time. Of course, all analogies break down at some point. The main point is that we have to take our foot off the freakin’ gas pedal and aim for the grassy green median immediately.

    Jim wrote, in response to Sean at #84 “As an antidote to a sense of hopelessness.”

    A worthy goal indeed, and one that I have to assume partly animated this whole post. But I fear the worthy goal has lead to a hasty and a bit shoddy post that feels more like spin than anything I’ve seen at this site. Even well intentioned spin, spin for the best of causes–to stave off despair–is still spin.

    From the inapt analogy, to getting the various relative sources of methane wrong, to choosing an example of sea bed far from the main area of concern–the vast and shallow Siberian continental shelf… it seems more hastily thrown together than other posts.

    Also, focusing on the shorter, decadal half life of methane, is fine, but a balanced paper should also point out that over that shorter time frame, methane is many times more powerful than 23xCO2 as a GHG.

    Comment by wili — 8 Mar 2010 @ 1:15 AM

  104. Well, I WAS less worried about methane. But if somebody stirs up a giant burp and the methane finds an ignition source, it makes a fuel-air explosion. If it is a truly giant burp, the explosion could be in the megaton range, or so I have been led to believe. RealClimate please do an article on the resulting fuel-air explosions. If it happens, it could dissuade people from further adventures of that type.

    Comment by Edward Greisch — 8 Mar 2010 @ 1:42 AM

  105. ccpo :”I said two years ago methane was a serious problem and that downplaying it could prove our undoing. Now, everything I feared is confirmed and the scale can, and will, only get bigger. This is a promise. Is it scientific? No. But it is fully logical within the context of warming –> methane –> warming –> methane… Speed of change is the only issue”

    What has been confirmed, except that other people than you are able to issue non scientific statements based on fear and irrationality ? the kind of loop you describe is characterized by a F retroaction factor (the product I have indicated) , producing an eventual amplification 1/(1-F) If you are not able to give an estimate of the Arctic temperature producing F ~ 1 (the location of the “cliff”), then your statement is useless.

    Comment by Gilles — 8 Mar 2010 @ 2:05 AM

  106. [Response: Oh is that a fact? David's one of the world's leading researchers on the carbon cycle, but discussing the relevance of this paper's implications (and others', recently) is not his job eh? OK then.--Jim]

    I didn’t say that wasn’t his job. I said minimizing it wasn’t. The articles here from RC touching on the subject have downplayed the threat consistently while it has consistently been accelerating. So far, I’ve been more accurate than they have. Why? I am not bound by training to dismiss that which I cannot prove. My point stands: be careful about being too careful, and even more so about influencing policy to the low risk side.

    Unless, of course, you want to go all Hansen on us and roll up your sleeves and really get into the fight. If so, the point is all the more important: the public must come to understand risk assessment and why we must act.

    Put another way, if you’re not ringing the alarm, your kind of part of the problem.

    [Response: Try to get something straight. The assignment of scientists is not to ring bells, nor is it necessarily to refrain therefrom. The job of scientists is to give the best possible description of what is happening and why, especially in an issue as contentious as this, where everybody and their brother has their own axe to grind. This should be obvious--Jim

    Comment by ccpo — 7 March 2010 @ 6:41 PM

    Read what you wrote again: you just repeated what I said. In this case, the best possible description is one that includes the risk assessment that the methane seeping we are seeing is potentially catastrophic, particularly on longer time lines, and that even on shorter time lines what we are seeing is surprising and alarming.

    [Response: I don't disagree with any of this. But I'm not trying to "downplay the threat" by pointing out that so far the methane sources from hydrates are small. David]

    I’m not sure which nerve it was I hit, but ease up, jim. We’re on the same side.

    Cheers

    Comment by ccpo — 8 Mar 2010 @ 3:19 AM

  107. Gilles,

    How can you write so many words but not comprehend words when you read them? When I predicted what would happen, then it did, the prediction was confirmed. What don’t you understand?

    Comment by ccpo — 8 Mar 2010 @ 3:33 AM

  108. There is evidence that the ESAS venting is a recent phenomenon, from the ‘Independant’ 2008,

    “The preliminary findings of the International Siberian Shelf Study 2008, being prepared for publication by the American Geophysical Union, are being overseen by Igor Semiletov of the Far-Eastern branch of the Russian Academy of Sciences. Since 1994, he has led about 10 expeditions in the Laptev Sea but during the 1990s he did not detect any elevated levels of methane. However, since 2003 he reported a rising number of methane “hotspots”, which have now been confirmed using more sensitive instruments on board the Jacob Smirnitskyi.”

    Comment by jcrabb — 8 Mar 2010 @ 6:15 AM

  109. Off topic I know but I would like to see a realclimate piece just on the water vapour feedback. How much it is. If say you increase CO2 by this amount and the atmosphere responds with a rise in temperature of x, how much does water vapour alone contribute as a feedback. The use of terms like relative humidity, specific humidity and dew point would probably help as it will ground the piece in language that we all hear regularly from weather forecasts. Also keep it clear that it is also the case that if the atmosphere cools then the water feedback cools it even further, it works both ways and perhaps include the modelling of volcanic eruptions and Pinatubo if there is good data on the water vapour feedback.

    Feedbacks keep coming up as a skeptic discussion point and because there are a number of feedbacks and some I believe quite complex I think it would be useful to have a piece just on the water vapour feedback as from my understanding it makes up a considerable part of the total feedback.

    Kevin

    [Response: Water vapour: feedback or forcing? - gavin]

    Comment by Oxford Kevin — 8 Mar 2010 @ 7:35 AM

  110. In fact, NOONE have the scientific background to make grand general assertions on anything. A single expert can´t even say that we have AGW. And you (Jim) can´t say hardly anything regardning fear-mongering, based on your expertise, since that is a domain for sociologists, communication experts and cultural theory. Since arguments from authority are so common in climate research nowadays, these consequences should also be taken seriously. Expertise is a very limited thing ….

    Comment by Andreas Bjurström — 8 Mar 2010 @ 8:02 AM

  111. And if the David here is David Archer, I don’t think I ever apologized for my ill-thought-out criticism of his book for using the correct formula for partial pressure, which I was convinced was wrong. David, my sincerest apologies for my jackass mistake and subsequent behavior.

    [Response: Yep, it's me. I musta got over it. Cheers, David]

    Comment by Barton Paul Levenson — 8 Mar 2010 @ 8:14 AM

  112. Banquo: The earth hath bubbles, as the water has,
    And these are of them. Whither are they vanish’d?

    MacBeth Into the air; and what seem’d corporal melted
    As breath into the wind. Would they had stay’d!

    It seems to me that the study is ominous just as this early scene on a blasted heath in the play is ominous. None of the decisions have been made yet that lead to tragedy but full foreshadowing is present. It should not be forgotten that in the end whole forests can move.

    Comment by Chris Dudley — 8 Mar 2010 @ 8:33 AM

  113. This is a helpful piece. But about the analogy, when driving the question should be “how worried should you be?” At 60 MPH: quite worried. But the power laws for injury and death in motor vehicle collisions tell us that the probability of injury increases with the 3rd power of increases in speed, and that the probability of death increases with the 4th power. At 90 MPH, then, you should be much more worried. Ocean methane might be small potatoes in a cool-headed risk analysis, but this marginal increase in vehicle speed is not small potatoes at all.

    Comment by epidemiologist — 8 Mar 2010 @ 9:10 AM

  114. David:

    Yes, the thermokarst lakes work is important in that the lakes provide an easy conduit (a shortcut) for thermal perturbations to actually access the hydrate “reservoir”. I think the reason that “fingerprinting” the source (peat or hydrate) matters is that those are two very different sources of methane, with different volumes attached, and so it is reasonable to ask if the processes ongoing and the geology involved logically support the ability to tap just one or both of these sources. It is also important for just basic science to know more about hydrate’s role in natural processes. Maybe they are accessible with less perturbation than thought. Mayne they will respond more vigorously than we think (aided by such things as thermokarst or overpressure-driven faulting and phenomena such as that discussed in the recent Jain and Juanes JGR paper. I agree, its all methane and the impact it has on climate does not depend on the source. But the potential size and reactivity of those sources is relevant.

    I also think that discussion of the Svalbard scenario in the context of the Arctic shelf setting only confuses things. We do see it alot. At Svalbard, hydrate is stable right to the seafloor. On the shallow-water shelf on the other hand, there is the issue that insufficient pressures mean no hydrate in the upper 200 m or so. They also have very different thermal histories, etc…

    Comment by Dennis Denuto — 8 Mar 2010 @ 9:37 AM

  115. In fact, NOONE have the scientific background to make grand general assertions on anything. Andreas Bjurström

    Aaand, the winner of the 2010 Epimenides prize for self-sabotaging claims is… Andreas Bjurström!!! A big hand please for Andreas!

    Comment by Nick Gotts — 8 Mar 2010 @ 9:42 AM

  116. ccpo :” When I predicted what would happen, then it did, the prediction was confirmed. What don’t you understand?”
    I simply don’t understand your criterion of being a “serious problem”. Why is methane a serious problem, since methane is naturally emitted all around the world in much larger amounts than what has been observed in Arctic, and there is no sign of “methane runaway ” on a global scale, and we are still in any case well below such a threshold ? so which prediction did you make that has been confirmed ?

    Comment by Gilles — 8 Mar 2010 @ 9:43 AM

  117. “110
    Andreas Bjurström says:
    8 March 2010 at 8:02 AM

    In fact, NOONE have the scientific background to make grand general assertions on anything. A single expert can´t even say that we have AGW”

    No one scientist has the background to make grand general assertions that we don’t.

    But we CAN say we have AGW.

    One single scientist can show through their own work that we have. And one did. Gilbert Plass, 1956.

    If 0.6-0.8C warming is due to CO2 we put out and the warming signal is 0.7-1.0C, then most of the warming is due to CO2 no matter what unknown unknowns we have.

    If we have 0.6C warming from CO2 then we have AGW, whether we have 0C or 2C from other sources: without CO2′s effect we would be cooler.

    Comment by Completely Fed Up — 8 Mar 2010 @ 9:50 AM

  118. A cogent argument. However, I have to disagree a bit with the conclusion “For methane to be a game-changer in the future of Earth’s climate, it would have to degas to the atmosphere catastrophically”.

    Although the evidence does not suggest that catastrophic degassing is imminent, it stands to reason that such a massive degassing would be preceded by an escalating series of feedbacks–which would include gentler methane hydrate degassing such as what we now see. The paleontological evidence of previous degassings suggests that at least some of these were preceded by CO2 greenhouse warming, perhaps with the CO2 furnished by flood basalts. The point is that initial CO2 warming can lead to melting permafrost, wildfires, albedo changes and the like, which begets still more methane hydrate melting…until an inflection point is reached and many of the remaining hydrates degas all at once.

    The issue is that we do not know the trigger sensitivity of the methane hydrate bomb (or clathrate gun, if you prefer). At what point does this cycle of slowly escalating feedbacks become self-perpetuating enough to precipitate massive hydrate degassing?

    There is the question.

    While we have yet to confirm this Siberian offshore degassing to be a consequence of recent warming, it fits exactly what many have forecast. It is indeed cause for concern.

    Comment by David — 8 Mar 2010 @ 9:57 AM

  119. Thomas @ 96:

    So there must(may) be something going on that favors atmospheric circulation patterns that either/or slow storm systems or allow trains of similar storms to hit the ame area. That this could be a result of warming is not at all intuitive!

    This is why “Global Warming” is, in my opinion, a less accurate term than “Climate Change”. While I’m grateful for the fact that this winter has been colder and wetter than average where I live, that “change” has come with a cost to people who’ve relied on either more average weather, or the “new average”, which is warmer and drier. The potential impact to agriculture, from more chaotic weather patterns, is not a pleasant thing to ponder.

    As for the storms, it’s a completely intuitive outcome — increased energy in the atmosphere results in more water vapor for a given relative humidity. Since the second derivative of water vapor concentration with respect to temperature is positive, the amount of precipitation for a given reduction in temperature increases.

    Comment by FurryCatHerder — 8 Mar 2010 @ 10:01 AM

  120. Gavin,

    Thanks for the response. But the piece Water Vapour: feedback or forcing to which you have referred and which I’ve read a few times now only answers part of what I am asking. But I think what I’m asking for is something simpler. Something along the lines of if you warm the atmosphere/ocean surface by 1 degree by adding CO2, what is the response of the level of water vapour in the atmosphere, and what does this mean in terms of the increase in temperatures due to water vapour.

    Why I feel this to be important is that as far as I can tell of all the feedbacks water vapour is by far the most important. Therefore if there was a clear and accessible explanation of how it works and what its implications are then it would be easier to push back over the claims that reject feedback or at least this particular feedback.

    Kevin

    [Response: Water vapour in the atmosphere goes up by about 7% per degree C increase (assuming that relative humidity is roughly constant which is a pretty good approximation). - gavin]

    Comment by Oxford Kevin — 8 Mar 2010 @ 10:06 AM

  121. 115, and the award for most narrow-minded attitude goes to Nick Goat!

    Comment by Andreas Bjurström — 8 Mar 2010 @ 10:07 AM

  122. “116
    Gilles says:
    8 March 2010 at 9:43 AM
    Why is methane a serious problem, since methane is naturally emitted all around the world in much larger amounts than what has been observed in Arctic,”

    Cyanide is naturally created by the human body. It is used in apoptosis to kill off infected cells.

    Yet if I were to lace your dinner with 1g of cyanide, this would have a catastrophic effect.

    Comment by Completely Fed Up — 8 Mar 2010 @ 10:22 AM

  123. Jimbo: Water Vapour, 40,000 parts per million.
    CO2, 360 parts per million
    Methane, 1.7 parts per million

    BPL: Percent of the clear-sky greenhouse effect caused by water vapor: 60%
    By CO2: 26%
    Fraction of airborne fluorine necessary to kill you: 1.0 parts per million

    Comment by Barton Paul Levenson — 8 Mar 2010 @ 10:36 AM

  124. Jimbo (91): For those who want to spend trillions shaving a small percentage of a trace gas called Co2 from the atmosphere then please see what a trillion dollars looks like.

    BPL: For those who think it’s more important to save money than to prevent a worldwide disaster then please see what widespread starvation looks like.

    http://images.google.com/images?hl=en&source=hp&q=starvation&aql=&oq=&um=1&ie=UTF-8&sa=N&tab=wi

    Comment by Barton Paul Levenson — 8 Mar 2010 @ 10:40 AM

  125. Andreas: “Goat”?!
    A gentleman never insults anyone unintentionally.

    Comment by Hank Roberts — 8 Mar 2010 @ 11:03 AM

  126. and there is no sign of “methane runaway ” on a global scale..

    Comment by Gilles — 8 March 2010 @ 9:43 AM

    You obviously do not wish to be serious. Denialism is sad, pointless, and ultimately suicidal. Let the data inform rather than your ideology.

    Cheers

    Comment by ccpo — 8 Mar 2010 @ 11:12 AM

  127. The issue is that we do not know the trigger sensitivity of the methane hydrate bomb (or clathrate gun, if you prefer). At what point does this cycle of slowly escalating feedbacks become self-perpetuating enough to precipitate massive hydrate degassing?

    Absolutely. It’s not just the clathrates on the ocean floor, it’s the tundra melting away, it’s the forests drying up, it’s the ocean dead zones, it’s the 95% decrease in large fish stocks, it’s the 80+% decrease in summer sea ice mass, it’s the sub-tropical water melting glaciers from the bottom up, it’s the warm Arctic Ocean melting sea ice from the bottom up…

    We are way past overshoot. It would be very useful for everyone to keep in mind that when these things happened in the past, there weren’t a bunch of hominids poisoning and depleting the planet in other ways to goose the whole thing into overdrive.

    This time is different and the past will not accurately reflect the present. Everything is going, and will continue to go, faster.

    Ironically, we’ve probably saved ourselves from a big freeze only to fall out of the freezer into the frying pan. It’s so blamed obvious that if we can preserve the carbon locked up now that we could conceivably keep the next glaciation at bay for quite a while, maybe even long enough to figure out how to live with the natural cycles of the planet…

    Comment by ccpo — 8 Mar 2010 @ 11:23 AM

  128. Chris Dudley, brilliant quote; it seems Macbeth really is all about methane?
    :)

    Comment by CM — 8 Mar 2010 @ 12:42 PM

  129. #98, yes, David, that YouTube vid (http://www.youtube.com/watch?v=oa3M4ou3kvw ) was exactly how they had it in BURN UP!

    What about this strongly negative arctic oscillation we had this year in which the arctic sent down it’s refrigerator breath to us, and giving well above average temps in parts of the arctic (I read it got up to even 7C above normal in the Arctic near Greenland).

    Would natural, random fluctuations like that — bringing more heat to the arctic — amplify now & then the increasing release of methane from AGW. And if so, those bursts, once the methane is out of the barn, so to speak, could further increase AGW.

    I mean, re the natural arctic warming/cooling fluctuations, it seems there might be greater impacts from the methane releases during the warmings, than from the reduced releases during the coolings IN THE CONTEXT OF AGW — the warming from AGW amplifying the natural warming spells, and keeping the natural cooling spells from dipping down too cold. It would have to do with the constant (temp at which ice melts, or methane is released from the ice).

    Or am I just thinking up another perpetual motion machine, and the natural fluctuations have equally positive and negative effects?

    [Response: The carbon cycle definitely amplified the glacial / interglacial cycles in just the way you're suggesting, but it wasn't methane that did that or even organic carbon (like trees and soils) but rather the ocean somehow. The special role for hydrates might be that the Earth could be warmer in the future than it has been in millions of years, so there could be a methane blow-off. But it would happen slowly, if it's paced by heat transport into the hydrates, not all at once. David]

    Comment by Lynn Vincentnathan — 8 Mar 2010 @ 12:51 PM

  130. Mike Strong, #13: “…it is gonna continue to get colder and colder each winter”.

    Your sentence left it open, but I nurse a fond hope that you actually do believe the fragment I quoted, because my retirement fund needs topping off, and I believe something resembling the opposite, and I would like to make a substantial and public bet on the subject. Please confess honestly that you don’t believe anything like that, or let’s find a venue to discuss the bet.

    Alas, I fear I’ll never find an honest sucker for my bet, because the posers just troll and disappear. On a not entirely unrelated note, the link from Mr Strong’s name appears to be spam for a dubious commercial entity.

    Comment by Ric Merritt — 8 Mar 2010 @ 1:57 PM

  131. Oxford Kevin: “Something along the lines of if you warm the atmosphere/ocean surface by 1 degree by adding CO2, what is the response of the level of water vapour in the atmosphere, and what does this mean in terms of the increase in temperatures due to water vapour.”

    Gavin didn’t really answer your last part, did he?

    My guess, assuming carbon dioxide alone is 1 K, is that adding the water vapor feedback raises it to 2.7 K, and clouds raise it to about 3 K. Would anyone with more knowledge care to correct these numbers?

    Comment by NoPreview NoName — 8 Mar 2010 @ 2:26 PM

  132. CCPO: Well put.

    Yes, present carbon stores could probably keep the next glaciation at bay for a few millennia, but I will settle for getting my kids and grandkids through life without major wars. That’ll be challenge enough if a runaway warming cycle is developing.

    Comment by David — 8 Mar 2010 @ 2:46 PM

  133. The first conclusion which can be made now – to be much more cautcious. It doesn’t help if we find reduction numbers on the paper, but in fact emission sky rocket. Be truthful, listen to the best data we have and adopt accordingly to our environment.

    Currently conservative IPCC targets have a hard time to be transported. Greenhouse gas from agriculture needs more attention. The biggest issue? Not even the US (biggest provider of emission in the past) has set a commitment for emission reduction.

    International leader should work out the fastest way for emission reduction.
    There should be a tax on greenhouse gases, the best infrastructure for the new technology and all the support. Companys which are effected from the shift to sustainable technology should be forced to upgrade. Seriously where is the problem to exchange fossil energy with wind/thermal/solar/biochar/etc energy generation?

    I read chevron builds a few solar shingle, but why not a few million? Seriously.
    This is a win-win situation in every possible way. Why not just upgrade? Where is the problem to replace my oil business with clean energy? Everyone participates – jobs, health, economy, money, security, customer, upgrades, technology, money.

    We need a race to sustain our economy. If africa has sustained energy and can grow crops – we can sell more to them. And more importend, we can continue to buy all those daily items we consume from 3rd world countrys. But in order todo this – we need sustainability in the first place.

    Comment by prokaryote — 8 Mar 2010 @ 2:52 PM

  134. CFU :”Yet if I were to lace your dinner with 1g of cyanide, this would have a catastrophic effect.”
    If my dinner were poisoned by 1 g of cyanide, I wouldn’t care of 0.01 g more ..

    ccpo :”Let the data inform rather than your ideology.”
    I have no ideology. Which data are you talking about, that show a threat of runaway ?

    Other question : if methane would be so sensitive to temperature, why didn’t CO2 vary that much in the past hundreds of millenia ?

    [Response: In fact both CO2 and methane varied cyclically through the glacial cycles, both probably as feedback to temperature which was originally driven by wobbles in the Earth's orbit. CO2 had a larger impact on the radiative forcing than CH4 did. David]

    Comment by Gilles — 8 Mar 2010 @ 4:06 PM

  135. 125 Hank Roberts,
    I´m not a gentlemen and neither are Nick Gotts.

    This is the logic behinds his attacks:
    I hate oceans. You are an oceanographer.
    I get angry when you say something tha reminds me of oceans.

    Well, what can I do, besides pouring some ocean water on him when he yells on me ;-P

    [Response: What people can do is ignore it. I have no interest in people using these threads to call each other names. Moderation is not perfect, and so some restraint is called for from commenters. Enough already. - gavin]

    Comment by Andreas Bjurström — 8 Mar 2010 @ 4:32 PM

  136. Gilles: “CFU :”Yet if I were to lace your dinner with 1g of cyanide, this would have a catastrophic effect.”
    If my dinner were poisoned by 1 g of cyanide, I wouldn’t care of 0.01 g more .. ”

    How does this make your statement

    “Why is methane a serious problem, since methane is naturally emitted all around the world in much larger amounts than what has been observed in Arctic,”

    true, then?

    Comment by Completely Fed Up — 8 Mar 2010 @ 4:36 PM

  137. My appologies if this has been addressed already (I didn’t have time to read all the posts) but concerning posts 14 and 19 about methane and the response:

    [Response: It is a fossil fuel. David]

    I just watched a documentary last night which included the fact that Titan (Saturn’s moon) has heaps of liquid methane on its surface. Are you suggesting that Titan once had abundant plant and/or animal life? Or do I misunderstand the meaning of “fossil fuel”?

    [Response: Just a fossil fuel on Earth. On Titan, not guilty. David]

    Comment by EdT — 8 Mar 2010 @ 4:38 PM

  138. RE: 13 (Mike S). All 50 states? Not mine (Washington). Faulty data set. We have seen no more than a short one-morning dusting of snow in Seattle this winter (2009-10), that back about the beginning of December, and no freezing termperatures since then – none. In fact, the entire northwest coast area has had an exceptionally mild winter – even up in B.C. and Alaska.

    Comment by Geno Canto del Halcon — 8 Mar 2010 @ 4:50 PM

  139. EdT:”Are you suggesting that Titan once had abundant plant and/or animal life? Or do I misunderstand the meaning of “fossil fuel”?”

    You’re misunderstanding a whole lot more than that.

    1) Methane is possible with abiotic sources. Many gas clouds are rich in such molecules. Hydrogen, Carbon, done. Therefore Titan doesn’t need abundant historic plant life

    2) Methane in and of itself is not a fossil fuel. Cow farts and organic waste decay are not fossil products. So Methane isn’t only a fossil fuel

    3) What happens on Titan and what happens on earth are not causally connected, the source of something on one is not proof of that being the source of the result on on the other.

    [edit]

    Comment by Completely Fed Up — 8 Mar 2010 @ 5:00 PM

  140. Interesting review and impressingly non-alarmist for being published on this site. I especially appreciate that the uncertainties are stressed instead of stowed away. I can, however, understand that people worry about methane but there is a simple argument against big trouble that I lack in this review. While we may argue about how big the problem is to restore some of the carbon back to the atmosphere that had been removed from the recycling in inaccesible deposits during a number of million of years making the CO2 abundance dangerously low the same is not quite true for methane. Nature has relatively recently done the methane experiment for us, and that repeatedly! It is called the end of the various ice ages. Each and every time one of the ice ages in the last million years ended huge tundra areas thawed, probably partly quite rapidly, and also, presumably, quite some hydrates were released from the neighbouring oceans. The results we know – we are here and the climate just got a lot better when the ice thawed. So the risk for run-away effects seems small by this simple argument.

    [Response: Except that this time, we're not exiting an ice age, and all GHG concentrations are significantly higher than when we were.--Jim]

    Comment by Steven Jörsäter — 8 Mar 2010 @ 5:33 PM

  141. I apologise if it is repetition, but I would really like a straightforward answer to this question, if one is available:

    Leaving aside the oceans, is it a reasonable possibility that we could pass a ‘tipping point’ when all the permafrost was committed to melting and releasing all its carbon (in whatever form) and hence committing us to a very large CO2 and temperature rise, even if it takes some time to come about? If not, why not?

    [Response: Without question, but that would take a long time to happen because tundra soils can be very deep, so whether "tipping point" is the best phrase is very debatable.--Jim]

    Comment by Josie — 8 Mar 2010 @ 6:40 PM

  142. re sudden non-linear large scale methane release in N Atlantic in the past – you are thinking of the Storegga slide see http://www.semp.us/publications/biot_reader.php?BiotID=301

    Lawrence Coleman — 7 March 2010 @ 5:47 AM and Thomas — 7 March 2010 @ 8:15 PM about slower moving storms – my understanding is that temperate zone large scale weather circulation is driven by the difference in temperature between the tropics and the poles; global warming decreases this difference (Arrhenius 1896), so the circulation slows; so it makes sense that precipitation events, having more water vapor to start with, and moving more slowly, would result in more extreme events.
    “The response of IPSL-CM4 is characterized by the same robust mechanisms affecting the other coupled models in global warming simulations, that is, an increase of the hydrological cycle accompanied by a global weakening of the large-scale circulation.” http://ams.allenpress.com/perlserv/?request=get-abstract&doi=10.1175%2F2009JCLI2794.1&ct=1
    “Theory, observations, and GFDL climate models agree that the Walker circulation weakened by about 3.5% during the past 150 years.” http://www.gfdl.noaa.gov/cms-filesystem-action/user_files/kd/pdf/gfdlhighlight_vol1n3.pdf
    Weak(er) Walker circulation results in strong(er) El Nino – “The impacts of El Niño upon climate in temperate latitudes show up most clearly during wintertime. For example, most El Niño winters are mild over western Canada and parts of the northern United States, and wet over the southern United States from Texas to Florida.” http://www.pmel.noaa.gov/tao/elnino/impacts.html
    Also compare http://www.bom.gov.au/climate/enso/d3a199798.shtml 97-98 El Nino rainfall with http://www.bom.gov.au/cgi-bin/silo/rain_maps.cgi?map=contours&variable=totals&area=aus&period=3month&region=aus&time=latest

    Comment by Brian Dodge — 8 Mar 2010 @ 6:44 PM

  143. re #140

    Actually, work by Sowers reported in Science (v 311, 838, subsequent work since by Petrenko Science 324, 506)and even several others all show that hydrates did not contribute to, or even noticeably respond to, any of the post glacial warming episodes. The best example where this might have happened is the PETM, and even there, the evidence is not conclusive.

    Comment by Dennis Denuto — 8 Mar 2010 @ 7:00 PM

  144. Dont’ panic…nuclear winter will solve global warming

    [Response: Awesome!]

    Comment by igmuska — 8 Mar 2010 @ 7:56 PM

  145. I am having some trouble reconciling what I read about water vapor feedback, both in Water vapor: feedback or forcing? and in the AR4 report, with my understanding of the greenhouse effect, which is as follows:

    According to the Stefan-Boltzmann law, the average insolation of 240 watts per square meter on the Earth’s surface should result in a temperature of -18°C.
    To remain in radiative balance, the Earth must radiate the same amount of energy, which means it must also radiate at an average temperature of -18°C.
    Because of the presence of greenhouse gases, the Earth radiates its energy from high in the troposphere, where the average temperature must be the same -18°C.
    Given the rate the atmosphere warms with altitude (the Lapse Rate, about 6.5°C / 1,000 m), the temperature at the ground is 33°C warmer.

    Doubling the level of carbon dioxide will raise the altitude at which the Earth radiates, which will come into balance at -18°C. Given a constant lapse rate, the surface will be further from the radiating altitude, and will therefore be warmer.

    Is it correct to interpret the consequence of adding carbon dioxide to be the raising of the air column temperature gradient higher into the atmosphere, and inserting a warmer layer of air below it? If so, and we assume both a constant lapse rate and relative humidity, there should be no change in the water vapor content of this air column because its temperature profile does not change. The added water vapor will be confined to the new layer near the surface, where it may greatly affect the climate but should have little effect on outbound radiation, because its temperature is about the same as the surface. By this reasoning there will be almost no water vapor feedback.

    If I am right so far, than water vapor feedback must come from changes in relative humidity and the lapse rate. But from what I read relative humidity seems to be considered relatively constant (it varies differently in different places) and the change in lapse rate is actually a negative feedback (IPCC AR4 WG1 8.6.2.3]. Given there seems to be good evidence for significant water vapor feedback, can someone please point out the error in my understanding?

    [Response: The relative humidity stays about the same, but the absolute humidity, the number of H2O molecules per total number of gas molecules, goes up with temperature. It goes up proportionally to the change in saturation vapor pressure. David]

    Comment by Blair Dowden — 8 Mar 2010 @ 8:11 PM

  146. “fossil fuel: a fuel (as coal, oil, or natural gas) formed in the earth from plant or animal remains” http://www.merriam-webster.com/dictionary/fossilfuel

    Regarding the debate over the meaning of “fossil fuel” – the politically correct term is now “hydrocarbon resources” (sorta like how “global warming” became “climate change”)
    For info on how the fossil fuel, er, hydrocarbon resource wonks at the Energy and Environment Directorate of Pacific Northwest National Laboratory (your tax dollars at work) regard methane hydrates,
    see http://www.pnl.gov/main/publications/external/technical_reports/FPNNL-17922.pdf

    “Gas hydrates are solids composed of crystalline cage-like molecular structures of water that each surround a gas molecule, (mostly methane, but also propane, ethane, and carbon dioxide). This hydrocarbon resource forms dominantly from microbial (biogenic) degradation of organic material, but also from thermogenic methane from deep, conventional hydrocarbon accumulations.”
    “A similar approach is now applied to gas hydrate reservoirs recognizing that there are differences in accumulation mechanisms for gas hydrate systems and that most gas hydrate systems form from biogenic methane and are geologically young relative to most conventional petroleum hydrocarbon systems.”
    “The youngest source rock across the Arctic is the Eocene Azolla interval, formed by the prolific freshwater floating fern Azolla during a time when the Arctic was largely enclosed, with elevated temperatures and a freshwater surface layer.”
    “Arctic marine permafrost relic from glacial low stands of sea level enhances the formation of gas hydrate.”

    Comment by Brian Dodge — 8 Mar 2010 @ 8:24 PM

  147. David, I want to apologize for pushing you to respond to “Ron” (whoever he is!) in my comment 68. No wonder you were annoyed. I should have spent a bit more time on his website. Having now done so, he clearly has an anti-scientific and irresponsable agenda.

    I want to reaffirm my appreciation of “The Climate Crisis” and also “The Long Thaw.”

    Thanks also for your clear, calm response to the methane fears.

    Comment by Ron Taylor — 8 Mar 2010 @ 8:53 PM

  148. Hank all I mean is methane should not be counted out yet either as a positive feedback or a contributor to more C02 levels; I cannot speak for the climatologists, but some less honest people may take that to mean that methane is not an important factor at all.

    Comment by Jacob Mack — 8 Mar 2010 @ 9:16 PM

  149. 145 Blair:
    That is a good try at trying to understand H2O feedback. I think the complication is that the opacity of the atmophere is frequency dependent -so it is not strictly correct to state that the energy radiated from space comes only from your level at -18C. Some atmospheric windows allow some direct thermal radiation from thr ground to make to directly into space, so the extra water vapour in your lowest layer does have an effect.

    Comment by Thomas — 8 Mar 2010 @ 9:32 PM

  150. Andreas Bjurström #110 objects to “arguments from authority”. What would you rather have, arguments from lack of authority?

    This sort of objection is very shallow and ignores the fact there is an enormous amount of published research in this field, as you would discover if you took the time to find it.

    Steven Jörsäter #140: if you read this site regularly you will know that contributors not only write regularly about uncertainties but anyone posting a comment that is unjustifiably alarmist or at odds with the evidence is usually corrected.

    Comment by Philip Machanick — 8 Mar 2010 @ 10:06 PM

  151. All I see is about radiative heat transfer. What about convection effects. Aren’t these significant espesially with el nino etc

    Comment by Prof T Heidrick — 8 Mar 2010 @ 10:22 PM

  152. David

    Thanks for the post and thank you to all at Real Climate for your great work.

    Being a farmer in the South West of Australia who is custodian of both sheep and cattle I tend to be sensitive to talk of methane. Could you put the production of methane from dams into some perspective? I have read that the it is estimated that we produce 120 million tonne of methane from dams around the world in one year.

    [Response: Don't know much about it but I don't get the impression it's a big deal. Sorry, David]

    Comment by Dale Park — 8 Mar 2010 @ 10:26 PM

  153. “They need to figure out where the methane is coming from and why. Then wait and see how it changes with time.” No proxy data with which to hindcast?

    [Response: Maybe someone will come up with something. Human ingenuity is an amazing thing. Ice core data can shed some light via the North / South difference, but it's crude. David]

    Comment by Nick — 8 Mar 2010 @ 11:12 PM

  154. “In fact both CO2 and methane varied cyclically through the glacial cycles, both probably as feedback to temperature which was originally driven by wobbles in the Earth’s orbit. CO2 had a larger impact on the radiative forcing than CH4 did. David”

    I know David, thanks.But can the amount of methane that can be released by a variation of a few degrees be comparable to the amount of fossil carbon that is currently burnt by mankind (at least 1000 Gt, may be more )? if no, how could it trigger a runaway , and if yes, why has CO2 not reached this kind of level (500 ppm or so) in during interglacial periods? wouldn’t it be an extraordinary chance that the natural variations has never released it before,giving a high CO2 concentration after being oxidized ?

    CFU :How does this make your statement
    “Why is methane a serious problem, since methane is naturally emitted all around the world in much larger amounts than what has been observed in Arctic,”
    true, then?

    Because what is observed to rise is only the 0.01 g , not the 1g, so there is no sign that we are nearing a tipping point.

    [Response: In the geologic past through the glacial cycles the climate feedback from methane has been smaller than that from CO2. However, as you note we're pushing CO2 beyond the limits of what it has been for millions of years. The methane hydrates in the ocean take millions of years to grow. So we may be pushing the hydrates to melt down in the future. We did calculations that if the feedback were too strong you'd see the hydrates melting down spontaneous throughout Earth history. You don't really see that, so the upper limit we predicted was that the hydrates could ultimately release as much carbon as we burn in fossil fuels. But the time scale for that is thousands of years, so the impact on climate over the next few hundred years would be small compared to that from fossil fuel CO2. David]

    Comment by Gilles — 9 Mar 2010 @ 2:26 AM

  155. Over the last 7 years the ESAS has developed 100 ‘hotspots’ of Methane venting, as warming continues, seems fair to expect more ‘hotspots’ to emerge.

    As the ESAS is estimated to contain 540 billion tonnes of Methane, it alone has the potential to cause substantial Global warming.

    The only question would seem to be the rate at which it increases to vent over the coming years, as this permafrost is collapsing far sooner than expected it would seem that it is more sensitive to temperature than expected, suggesting a fast rate of collapse is likely.

    Comment by jcrabb — 9 Mar 2010 @ 3:50 AM

  156. Gilles: “Because what is observed to rise is only the 0.01 g , not the 1g”

    No, that still doesn’t make “why is methane a problem when we’re getting it naturally” true.

    Go look up the volume of methane in the atmosphere and the amount of methane trapped in the tundra and under the water.

    [edit]. Do something real. Investigate.

    Comment by Completely Fed Up — 9 Mar 2010 @ 4:04 AM

  157. Prof T Heidrick #151: of course climate modellers are aware of convection and it is part of the models. Just because it isn’t being discussed in this article doesn’t mean it’s ignored. Try the search box at the top of the page.

    Comment by Philip Machanick — 9 Mar 2010 @ 5:30 AM

  158. Haven’t Paleontologist found good evidence of catastrophic methane release in the past? What you are observing right now on the edges of the stability border of methane hydrate in the oceans might just be a precursor of future catastrophe?

    [Response: The PETM is the poster child, but the combination of the carbon and oxygen isotopes seem to rule out methane as the source, you wouldn't get enough carbon to get as much warming as the oxygen isotopes tell you, unless the climate sensitivity was something like 7 degrees for doubling CO2. So I don't personally believe it could have been methane. David]

    Comment by James Farrell — 9 Mar 2010 @ 7:59 AM

  159. Thanks, David, for the response about the water vapor feedback question. I did not take into account the change in air pressure with altitude, but that seems to make things even worse. The number of H2O molecules per total number of gas molecules goes up with temperature, but the radiative effect of these molecules goes down, because they are warmer.

    I imagine a “box” of air at any given altitude, which has a certain number of water vapor molecules depending on its temperature. If we now double the amount of carbon dioxide, the box gets warmer. So I move the box higher to get it back to the same temperature. But being higher, there are now less molecules in it, including water vapor molecules, than before. So it will have less radiative effect than before. This is true for a box of air at every altitude. The only new “boxes of air” are added near the surface, where they are warm and do make much difference to the greenhouse effect.

    I have now conjured up a negative water vapor feedback. Please explain the error in my reasoning.

    Comment by Blair Dowden — 9 Mar 2010 @ 9:25 AM

  160. “I have now conjured up a negative water vapor feedback. Please explain the error in my reasoning.”

    The problem is here:

    “So I move the box higher to get it back to the same temperature. But being higher, there are now less molecules in it, including water vapor molecules, than before.”

    But you have more boxes. Therefore the total may go up or down.

    Comment by Completely Fed Up — 9 Mar 2010 @ 9:42 AM

  161. Blair,
    That’s an utterly bizarre formulation. What matters is the number of potential ghgs between a photon and space. It’s not that you cease to have radiation at lower levels, but that it just doesn’t escape. Try looking at the atmosphere in columns rather than boxes.

    Comment by Ray Ladbury — 9 Mar 2010 @ 10:36 AM

  162. Re 160 – CFU, I am saying the new boxes are all at the bottom of the atmosphere, where they do not have much impact on the greenhouse effect.

    Re 161 – Ray, my understanding is that the greenhouse effect depends on the temperature of the gas from which the radiation escapes into space. If a low altitude ghg radiates directly into space, its temperature is about the same as the surface, so it makes little difference to how much energy is lost. If the radiation is intercepted by another molecule, than the lower molecule no longer matters.

    I tried to look at the atmosphere in a column. Given constant relative humidity and lapse rate, increasing carbon dioxide raises the entire column to a higher level. There is no change in the temperature structure. A warmer layer is inserted below it, so the surface warms.

    Thanks for your response. I know there must be something wrong with my understanding, and I appreciate any help you can give.

    Comment by Blair Dowden — 9 Mar 2010 @ 12:28 PM

  163. “Re 160 – CFU, I am saying the new boxes are all at the bottom of the atmosphere, where they do not have much impact on the greenhouse effect.”

    Then you say you lift them up.

    How can this leave them at the bottom of the atmosphere?

    Comment by Completely Fed Up — 9 Mar 2010 @ 12:41 PM

  164. Interesting example [methane generating?] of the morphs that lead to contrarian hysteria – the study “Large-Scale Controls of Methanogenesis Inferred from Methane and Gravity Spaceborne Data” leads to headline “Arctic permafrost leaking methane at record levels, figures show” [Guardian of course], which leads to “Methane Madness”. The comments at the Guardian and “American Tinker” are entertaining, but depressing. Seems more attention to public education on the range and interaction of all greenhouse gasses is needed.

    Comment by flxible — 9 Mar 2010 @ 12:58 PM

  165. This viz mechanism for methane release:

    The 3000 km3 Storegga submarine landslide occurred c. 8150 years ago from an area rich in gas hydrates off the western coast of Norway. A synchronous increase of 80—100 ppb in atmospheric methane concentrations is recorded in the Greenland GRIP ice core. This increase is hypothesized to reflect methane releases from the Storegga slide debris at an estimated rate of 20—25 Tg/yr for several hundred years following the slide. Methane is a powerful greenhouse gas, and methane release from the Storegga submarine landslide may have contributed to the rapid termination of the brief but intense 8200 yr cold event and the subsequent evolution of Holocene climate.

    Earthquakes or simple destabilization of shelves could lead to a possible methane release; couple this with increasing water temperature, and I could see how there could be a sudden surge in greenhouse effects…

    [Response: The Storegga slide could have released about a gigaton of carbon as methane at most, which would have increased the atmospheric concentration by maybe a third, about the same climate perturbation as a large volcanic eruption but warming rather than cooling. The slide coincided more or less with the 8.2k climate event, which was a cooling driven by ocean circulation and the methane concentration went down, not up. Anyway, an increase of 100 ppm would be a very small climate impact. I think you'd need simultaneous storeggas all around the world to get a climate kick from the methane. David]

    Comment by Steve Missal — 9 Mar 2010 @ 12:58 PM

  166. I think this is your problem:
    > If the radiation is intercepted by another molecule,
    > than the lower molecule no longer matters

    “no longer matters” is wrong. It’s the delay time you’re omitting.

    Hmmm, a venture into recreational typing, top o’ my head version:

    The added greenhosue gas molecules near the surface are _delaying_ the transfer of heat, extending the time it takes moving out from the surface, spreading the heat to the surrounding air, which conveys heat back to greenhouse gases and to the surface by conduction, convection, and radiation. Meanwhile above those warming lower layers, the higher layers have more CO2 intercepting less heat from below, and the upper layers cool.

    Comment by Hank Roberts — 9 Mar 2010 @ 1:07 PM

  167. But Blair, what happens is that the ghg in the new radiating layer is colder, and so radiates less than the gas in the the old one. Stefan-Boltzmann Law.

    Comment by Ray Ladbury — 9 Mar 2010 @ 1:37 PM

  168. By formulating the problem as boxes, instead of masses, you forgot to preserve mass balance. By adding a new box at the surface, the box “jacked up” at altitude has fewer molecules, but the left over molecules don’t disappear. They go into a new box, at altitude, so the statement “The only new ‘boxes of air’ are added near the surface,” is wrong.

    To really understand what happens, you gotta run a line by line and layer by layer calculation (model), and compare them against others models. see http://www.ametsoc.org/atmospolicy/documents/071029Soden.pdf

    Comment by Brian Dodge — 9 Mar 2010 @ 2:01 PM

  169. What about the danger than James Hansen highlights, of methane release triggering a PETM-type warming event on top of the warming caused by other GHG emissions?

    Is runaway climate change possible? Hansen’s take

    [Response: Or carbon release from peats, or soil carbon, or biomass, or the ocean somehow-like-it-did-during-the-glacial-cycles. Methane is not the only game in town. David]

    Comment by Milan — 9 Mar 2010 @ 2:40 PM

  170. Some people take comfort from the fact that there have been times in the history of the planet when greenhouse gas concentrations were much higher than now. The world was very different, but there was no runaway greenhouse and life endured. James Hansen devotes the entire tenth chapter of Storms of My Grandchildren to considering whether this assessment is valid. Three things give him pause:

    1. The sun is brighter now than it was during past periods with very high greenhouse gas concentrations. The 2% additional brightness corresponds to a forcing of about 4 watts per square metre and is akin to a doubling of CO2 concentrations.
    2. For various reasons, the greenhouse gas concentrations in past hot periods may not have been as high as we thought.
    3. We are introducing greenhouse gases into the atmosphere far more quickly than natural processes ever did. This might cause fast (positive) feedback effects to manifest themselves forcefully, before slower (negative) feedback effects can get going.

    He also explains that the sharp warming that took place during the Paleocene–Eocene Thermal Maximum (PETM) were not caused by fossil fuels (which remained underground), but rather by the release of methane from permafrost and clathrates. If human emissions warm the planet enough to release that methane again, it could add a PETM-level warming on top of the warming caused by human beings.

    In this post, are you saying that is unlikely to happen at all, or just that it would be likely to take a long time? What do you think about his concerns about methane kicking off runaway warming? Hansen says that: “While that is difficult to say based on present information, I’ve come to conclude that if we burn all reserves of oil, gas, and coal, there is a substantial chance we will initiate the runaway greenhouse. If we also burn the tar sands and tar shale, I believe the Venus syndrome is a dead certainty.”

    Comment by Milan — 9 Mar 2010 @ 3:26 PM

  171. Hank, I am trying to use a radiation balance model. The Earth receives a certain amount of radiation from the sun, and must radiate the same amount out to keep its temperature in balance. So the only greenhouse gas molecule that matters is the one that radiates into space.

    This is like managing your bank balance, all you do is subtract withdrawals from deposits (assuming you trust the bank). You do not pay attention to all the transactions that happen inside the bank with the money you deposit. I view your discussion of conduction and convection as internal transactions which can be ignored when calculating radiation balance. In reality, convection may affect the lapse rate, but I am assuming a constant lapse rate for now.

    For water vapor feedback to add to the greenhouse effect, you need to get more water vapor molecules up to a higher altitude, where they will radiate at a lower temperature, so less energy is “withdrawn” from the earth system. The only mechanism (I am ignoring convection, maybe that is the problem) to get the water there is the Clausius Clapeyron law, basically saying warmer air holds more water vapor.

    A column of air has a certain temperature profile, determined by the lapse rate.
    Doubling carbon dioxide simply raises that temperature profile of a vertical column of air higher into the atmosphere, assuming constant lapse rate. That is what lapse rate means.

    Assuming water vapor concentration depends only on temperature, the proportion of water vapor will not change. The amount of water vapor will be less, because the air is thinner. So there are less water molecules to intercept radiation, and re-radiate at a cooler temperature.

    Mass balance is maintained by the new warmer layer at the surface (underneath the “raised” column of air), which will have more water vapor that was there before. So there is more total water vapor in the atmosphere, but the additional water vapor is all near the surface, where it will radiate at a high temperature, and have little greenhouse effect.

    I hope this makes my thinking clearer, and I hope someone will point out specifically where the problem is. I appreciate the help so far.

    Comment by Blair Dowden — 9 Mar 2010 @ 4:14 PM

  172. Hello again.My comment is #27.I just read up to comment # 172.There are many excellent comments which quickly educated me even further.That’s why I like this site.Tons of highly educated people commenting on things I care about deeply.So, thanks to everyone here for their time and comments.
    Geez Louise, folks it sure does look like there is a lot to be concerned with.Notable are comments #165,#169 and #170 among many other notable comments.Also,Hansen has it right.No question at all on that.

    Mark J.Fiore
    markfiore50@hotmail.com

    Comment by Mark J. Fiore — 9 Mar 2010 @ 4:48 PM

  173. Re Blair Dowden 171:

    Well, the vapor pressure of water vapor increases roughly exponentially with increasing temperature for constant RH. Thus, assuming constant RH, a temperature increase will increase the water vapor pressure.

    For the sake of the argument, if the RH profile shifts upward with the temperature profile (let’s say it shifts upward by an amount h), the water vapor pressure profile shifts upward, which generally means more water vapor at a given height level. (PS Note that the same water vapor pressure at lower atmospheric pressure actually means an increase in mixing ratio (specific humidity).) In that case, the water vapor would be at the same temperature relative to a coordinate that shifts upward by h, but there is then the additional water vapor near the surface. But with the temperature increasing at the bottom of the temperature profile, there is a greater temperature difference between the water vapor above h from the surface and the surface and water vapor beneath h. Aside from some variations in line broadenning, the water vapor reduces the upward LW flux at the tropopause more not because it is colder but because the surface and lowermost water vapor are warmer (or if the lowermost water vapor completely blocked surface radiation, then the effect of the water vapor above that would not have changed, since the temperature at the top of the lowermost water vapor would be the same as the surface temperature before, but then there would not have been any increase in the outgoing LW flux in response to warming – actually there would be some increase due to the nonzero LW albedo at the surface, but anyway…). Thus the increasing temperature has not increased the net upward LW flux as much as it would have if water vapor were held constant relative to atmopheric pressure or geometric height.

    Comment by Patrick 027 — 9 Mar 2010 @ 5:30 PM

  174. Blair, did you do the exercise recommended by Brian Dodge’s pointer at 168 yet?

    When you “run a line by line and layer by layer calculation (model), and compare them against others models. see http://www.ametsoc.org/atmospolicy/documents/071029Soden.pdf ” — where does your model fall compared to those charted there? I’d guess it’s well outside (below) the bunch of them?
    But those as shown are in the range of what’s observed; how would the chart drawn from your model correspond?

    Seems like “do the math, show the work” is the answer — people can comment on the work once they see it, but not by imagining what it would look like.

    Comment by Hank Roberts — 9 Mar 2010 @ 5:33 PM

  175. PS, some of these are ‘fill in the blank’ approaches as I recall
    http://www.google.com/search?q=simple+climate+model

    Comment by Hank Roberts — 9 Mar 2010 @ 5:34 PM

  176. [Response: The relative humidity stays about the same, but the absolute humidity, the number of H2O molecules per total number of gas molecules, goes up with temperature. It goes up proportionally to the change in saturation vapor pressure. David]

    This is totally off topic…but a lil curiosity i havnt been able to google the answer too… but what you say here is what i lean towards..

    I guess this is global, but optical depth seems variable on air pressure, its an old farmers weather prediction method. So during a high pressure, distant objects(mountains etc) appear more distant, with less visible definition to the details, and appear closer with greater visble detail pre a change in the weather… Is this the result of the SW light being scattered/or absorbed by the greater density o water molecules in the atmosphere during a high pressure system?

    Random i know, but im curious.

    Comment by Mike — 9 Mar 2010 @ 5:52 PM

  177. Blair Dowden, in your conceptual model, presume that the outgoing radiation comes from three separate IR bands, a CO2 band emitted from its effective emission height, an H2O band emitted from its effective emission height, and a window band emitted from the surface. When the CO2 amount increases, the effective emission height for CO2 lifts, warming the entire temperature profile for radiation balance. The warmer profile now holds more H2O, so the effective emission height for H2O lifts as well, and the temperature must get warmer again.

    bandwidth(CO2)*(T(surface)-gamma*height(CO2))^4 +
    bandwidth(H2O)*(T(surface)-gamma*height(H2O))^4 +
    bandwidth(window)*(T(surface))^4 = constant

    Comment by Imback — 9 Mar 2010 @ 6:23 PM

  178. Re Blair Dowden 171 – part II

    More generally, the absence of water vapor feedback is when the mixing ratio and thus the vapor pressure (setting aside the minor effect that adding water vapor increases total atmospheric mass just a little) doesn’t change at any level. In that case, warming increases the net LW flux out at the tropopause level (cooling of the stratosphere would do the same thing; effects of changes in stratospheric temperature in response to radiative forcing before any response are included in the tropopause level radiative forcing with equilbrated stratosphere; both the stratosphere and troposphere and surface, etc, change farther in the total response (the stratosphere adjusts to tropospheric changes, that is another source of feedback)).

    Now, after the temperature changes, add water vapor at any level within the troposphere (or for that matter, the stratosphere – in spite of stratospheric cooling, changes in the troposphere could inject more water vapor into the stratosphere (a generally dry place to begin with, due to the cold of the tropopause level)). That will reduce the net outgoing LW flux at the tropopause level. Water vapor at all levels (and all places and times) is not equal, and in some conditions the opposite could be true (water vapor on top of a low-level inversion), but it is generally true (and it would be odd if the only increases in water vapor were at the tops of low-level inversions).

    And so on for other feedbacks…

    Comment by Patrick 027 — 9 Mar 2010 @ 7:06 PM

  179. Re 170 – I agree bad things would happen, but I’m a little surprised by the Venus reference.

    It’s been a while since I’ve read this stuff but I vaguely recall:
    Earth would start to lose signficant amounts of the ocean to space when specific humidity (volumetric mixing ratio) ~ 20 % (presumably at the surface), which would correspond to a temperature of …? (factor of ~ 1.2 increase per 3 K, … um, um, … approx 30 K warmer?) and that would take awhile. We’ll have a lot to deal with before we ever get into Venus territory, I think.

    I think James Kasting wrote some things on this topic, perhaps in response to “Rare Earth”.

    Comment by Patrick 027 — 9 Mar 2010 @ 7:29 PM

  180. [Response: I don't disagree with any of this. But I'm not trying to "downplay the threat" by pointing out that so far the methane sources from hydrates are small. David]

    Comment by ccpo — 8 March 2010 @ 3:19 AM

    I don’t think I specifically said you were trying to, per se, only that you are. I said in at least one of my posts on this topic that scientists are held back by the scientific rigor and the unwillingness to take leaps of faith, intuition, etc.

    I suggest you embrace them, instead.

    There is a degree of semantics and interpretation here, certainly, but when we take all the evidence we have collectively, the methane seepage thus far is dang alarming. I see your article above as not providing full context and accepting the purely scientific, verified evidence as all of the evidence.

    What we know of non-linear systems and the much-faster-than-expected progression thus far tell us that underestimation is likely a very bad idea.

    Cheers

    PS. In case i don’t say it often enough, I love you guys, man!

    Comment by ccpo — 9 Mar 2010 @ 9:05 PM

  181. Actually, work by Sowers reported in Science (v 311, 838, subsequent work since by Petrenko Science 324, 506)and even several others all show that hydrates did not contribute to, or even noticeably respond to, any of the post glacial warming episodes. The best example where this might have happened is the PETM, and even there, the evidence is not conclusive.

    Comment by Dennis Denuto — 8 March 2010 @ 7:00 PM

    It was pointed out above, by David, I believe, that GHG levels are higher than at any time coming out of an ice age in the past. They’re higher than for a very, very long time. Also, that bit about the 1.8 parts per whatever for methane?

    This is not Kansas, Toto.

    Comment by ccpo — 9 Mar 2010 @ 9:23 PM

  182. First, let me be clear that I do not believe my “result” that there is no water vapor feedback. I am aware that both modeling and empirical results indicate that it is significant. I am trying to understand how it works so I can explain it to others. This should be possible without doing a line by line calculation.

    Does anyone have a problem with the following: Low altitude water vapor has little impact on the greenhouse effect from a radiation balance point of view. This water vapor may absorb every single photon in its absorption band, but Kirchhoff’s Law says they will be emitted again at the same wavelengths. They are at about the same temperature as the Earth’s surface, so this re-emission does not change the energy balance. (See page 152 of this Pierrehumbert paper.) However, this process may affect convection, which change the temperature distribution of the atmosphere.

    Patrick 027, you said “water vapor reduces the upward LW flux at the tropopause more not because it is colder but because the surface and lowermost water vapor are warmer.” I do not understand this statement. Temperature difference affects convection, but not radiation.

    Imback, I agree with your statement up to the conclusion. The effective emission height for H2O is raised, but so is its temperature. I fail to see how that changes the radiation balance.

    I think the problem is that the atmosphere is not saturated with water vapor, so Classius Clapeyron is not sufficient to determine moisture content. Relative humidity may change, perhaps differently at different altitudes. Also, changes in convection may be important. It would be nice to have some idea how all this works.

    Comment by Blair Dowden — 9 Mar 2010 @ 10:54 PM

  183. Blair wrote:
    Imback, I agree with your statement up to the conclusion. The effective emission height for H2O is raised, but so is its temperature. I fail to see how that changes the radiation balance.

    I do understand you want a heuristic model. The situation is tricky because H2O depends on temperature and temperature depends on H2O, so we have to think in simultaneous equations.

    Let’s start from the radiation balance equation (bottom of post 177). (Note gamma is the lapse rate.) –

    bandwidth(CO2)*(T(surface)-gamma*height(CO2))^4 +
    bandwidth(H2O)*(T(surface)-gamma*height(H2O))^4 +
    bandwidth(window)*(T(surface))^4 = constant

    Let’s assume constant RH and a linearized Clausius-Clapeyron (here the baseline heights and temperatures are subtracted, and chi is the linearized C-C slope) –

    (height(H2O) – height(H2O)@t=0) = (T(surface) – T(surface)@t=0)*chi

    So now we raise height(CO2). Algebraically we can see that T(surface) will increase, holding more H2O so height(H2O) goes up, which will force a further increase in T(surface) to keep the radiation balance.

    Comment by Imback — 10 Mar 2010 @ 12:31 AM

  184. Re Blair Dowden – it should be clear from my subsequent comment (first increase the temperature, then add water vapor and see what that does).

    Comment by Patrick 027 — 10 Mar 2010 @ 12:56 AM

  185. 154.”No, that still doesn’t make “why is methane a problem when we’re getting it naturally” true.

    Go look up the volume of methane in the atmosphere and the amount of methane trapped in the tundra and under the water.

    [edit]. Do something real. Investigate.”

    Obviously David’s answer is much more relevant to my question than your comment. Thanks David.

    Comment by Gilles — 10 Mar 2010 @ 1:33 AM

  186. The main points seem to be:

    1) Right now, the methane from the Arctic is a small percentage of total methane sources.

    2) There is no clear mechanism for sudden, catastrophic release of all this methane.

    Even if we set aside problems with these assertions, it seems to me that if this is the beginning of a new vast (how vast? anyone have the latest estimates?) source of carbon emissions into the atmosphere, this is a bad thing, whether in the long or short term. The researchers themselves say that studies in the ’90 found no such methane release, so either the release now is part of some cyclical pattern we don’t understand, or it is the beginning of something new.

    So this in turn leads to two questions:
    1) Is there any evidence or theory of what kind of cyclical event this could represent?

    2) Is there any kind of negative feedback that would likely stop this, if it is a new trend.

    If this is a new trend, and the answer to the second question is no, then even if this may not represent some kind of Hollywood doomsday in an hour scenario, long term it will greatly exacerbate (at least) already very bad prospects for the planet.

    Comment by wili — 10 Mar 2010 @ 4:12 AM

  187. Re:142 Thanks Brian
    You explained the slow storm effect very well. Because the tropics are warming at a slower rate than the sub tropics and temperate zones the whole world is indeed entering the ‘greenhouse effect’ scenario very clearly. Ok the earth will probably never resemble the extremes of venus but it’ll still too hot hot for intelligent life to flourish.
    Thanks ccpo that that bit of plagerism. If I was writing for a newpaper I’d sue you..haha!
    Least I know we’re on the same wavelength.

    Comment by Lawrence Coleman — 10 Mar 2010 @ 5:29 AM

  188. Blair (162),

    If you like, I can send you a tutorial I wrote on column atmosphere models (directed originally at deniers on an amazon.com forum, thus the occasionally sarcastic tone). I plan to incorporate it in a book, so I can’t publish it on the web. You’ll require a programming language to follow the examples; the one I use in the tutorial is Just Basic, which is a free download.

    Comment by Barton Paul Levenson — 10 Mar 2010 @ 6:44 AM

  189. Blair,

    The vapor pressure of water is higher as temperature climbs. Check out the Clausius-Clapeyron relation.

    Manabe’s team used the equation RH = 0.77 * (P/Ps – 0.02) / 0.98 for relative humidity at different altitudes (I think this overestimates it in the stratosphere, but that’s another story). Here P/Ps is atmospheric pressure relative to sea level. There’s an unphysical discontinuity at P/Po = 0.02, so above that they just assumed RH = 0.000003.

    Actual vapor pressure = RH x saturation pressure, and Clausius-Clapeyron gives the saturation pressure.

    Comment by Barton Paul Levenson — 10 Mar 2010 @ 6:51 AM

  190. Imback and Patrick 027, we all agree that water vapor at every level will increase when carbon dioxide is increased. The issue is that its temperature is also increased, so it is not clear what the net radiative effect will be.

    Observation shows that the increase is large enough to have a net positive radiative effect. I am trying to understand why. I am saying that if relative humidity and lapse rate are held constant this will not happen, and no one has shown that logic is wrong. Something else is happening.

    Comment by Blair Dowden — 10 Mar 2010 @ 8:02 AM

  191. Blair, your conceptual model should work even keeping relative humidity and lapse rate constant. We can see it in the algebraic argument, so it must work in the heuristic argument. Your logic error may be that you are double counting the first temperature increase. The first temperature increase perfectly offsets the increase in CO2. It’s already in balance without changing the H2O. Now raise the H2O due to Clausius-Clapeyron. The radiation becomes unbalanced again even with the first temperature increase. So a second temperature increase is necessary for balance.

    Comment by Imback — 10 Mar 2010 @ 9:01 AM

  192. Blair, define what you mean by “net positive radiative effect”. Are you saying that it’s a positive feedback or that it’s emitting more radiation?

    Comment by Ray Ladbury — 10 Mar 2010 @ 9:04 AM

  193. Slightly o.t., as roughly 25% of the current rise of atmospheric Methane is due to increased Wetlands emissions wouldn’t there be a similar rise of Methane during the ‘Medieval warm period’, if it was as warm as the current period? The levels of Methane for the last thousand years have been pretty much constant until recently, as shown here, http://joseph44.users.sourceforge.net/climate/graphs/ch4-etheridgeetal-reconstruction-1008-1993.JPG
    “Historic CH4 Records from Antarctic and Greenland Ice Cores, Antarctic Firn Data, and Archived Air Samples from Cape Grim, Tasmania”

    [Response: Interesting question. It was very dry during the Medieval time, maybe that slowed down methane production in wetlands. Today the methane is high not because of the warm temperatures but because of livestock farting, rice farming, and leaking fossil fuels. David]

    Comment by jcrabb — 10 Mar 2010 @ 9:07 AM

  194. Ok the earth will probably never resemble the extremes of venus but it’ll still too hot hot for intelligent life to flourish. – Lawrence Coleman

    Whatevergate would seem to indicate that it already is :-d

    Comment by Nick Gotts — 10 Mar 2010 @ 9:13 AM

  195. David said: “But the time scale for [total methane hydrate release] is thousands of years, so the impact on climate over the next few hundred years would be small compared to that from fossil fuel CO2.”

    Somehow, I don’t find this very comforting. I guess I’d like to know the sober assessment of the likelihood that the releases reported in the Science article are in fact a new feedback that, over whatever timescale, will eventually lead to carbon releases on a par with all ff sources of atmospheric carbon to date.

    Even if it on a timescale of thousands of years, that does not bode well, to my mind, for the future of life on earth.

    Yes, some of us do care about the future long after we and everyone we knows are long gone. Perhaps more need to start thinking on these timescales.

    And again, thanks for all the good work you do here.

    Comment by wili — 10 Mar 2010 @ 9:24 AM

  196. Thanks for the post David. I was wondering if you might be interested in posting on RC a response to David Archibald’s recent post at WUWT:
    http://wattsupwiththat.com/2010/03/08/the-logarithmic-effect-of-carbon-dioxide.

    He’s using the Modtran data again, this time to hind-cast a bit and suggest that the “IPCC models” (obviously run from the vast underground layer at the IPCC World Domination Headquarters) make anthropogenic warming fundamentally different from natural warming – thus that AGW is all rubbish. It’s attracted a lot of ooo’s and ahhh’s from Watts’ crowd, so I would love to hear your treatment of the matter.

    As a plant ecologist, my favorite part is “Plant growth shuts down at 150 ppm, so the Earth was within 30 ppm of disaster [during the ice ages].” Say what?!! How many ACi response curves have you actually looked at, Mr. Archibald?

    [Response: Yeah, this guy is over the line. Of course the radiative forcing from CO2 is logarithmic, I pointed out the same thing in my global warming textbook, and I'll be teaching it to a full classroom of undergraduates in about a month. It's not news, the models know all about it. I've seen Mr. Archibald's work before. It's weird he's using the model I posted on line (for the class, actually), but, hey, transparency, what're ya gonna do? David]

    Comment by ABG — 10 Mar 2010 @ 9:50 AM

  197. Are there simulations of the climate which include a methane hydrate dissociation model (like tough+hydrate) in their ocean-atmosphere coupling ?

    Comment by Jean-François B. — 10 Mar 2010 @ 9:53 AM

  198. Ray, by the poorly chosen term “net positive radiative effect” I mean that a positive feedback is observed in the real world.

    Imback, I am saying that after I “raise the H2O due to Clausius-Clapeyron”, the water vapor is warmer, so it will radiate at a higher temperature, and more heat will be lost from the Earth system. More water molecules, but less effect from each. The mathematically inclined may want compare the exponential gain in water molecules with the fourth power of temperature in the Stefan Boltzmann law. I suggest that any layer is equivalent to a previously lower layer, except maybe fewer overall molecules. Always assuming constant relative humidity and lapse rate.

    But back to the real world, the atmosphere is not saturated with water vapor, so Clausius-Clapeyron does not actually drive anything. The changes in water vapor must be driven by other forces, such as convection.

    Comment by Blair Dowden — 10 Mar 2010 @ 12:34 PM

  199. Re Blair Dowden – what Imback 191 said; or in other words:

    The water vapor feedback is the change in LW flux (tropopause level or top-of-atmosphere or …, depending on context, but the first is of key importance) at a given temperature distribution, after the temperature has changed and before the temperature changes again in response to the feedback (or it can be described in terms of the further temperature change that results).

    A radiative forcing occurs; to restore radiative balance, a change in temperature must occur. Without any other changes, x K warming increases net outward LW flux. But then water vapor increases, reducing the net outward LW flux from what it would be if only the temperature changed. Thus the temperature has to change more to restore balance.

    Comment by Patrick 027 — 10 Mar 2010 @ 1:46 PM

  200. @ Blair Dowden — 9 March 2010 @ 10:54 PM “It would be nice to have some idea how all this works.”

    background info -
    http://en.wikipedia.org/wiki/Lapse_rate
    http://www.ipcc.ch/ipccreports/tar/wg1/266.htm
    http://www-das.uwyo.edu/%7Egeerts/cwx/notes/notes.html
    http://www-das.uwyo.edu/%7Egeerts/cwx/notes/chap08/moist_cloud.html
    http://www.realclimate.org/?comments_popup=2817#comment-161863
    http://svs.gsfc.nasa.gov/vis/a000000/a003600/a003648/index.html

    Data to play with -
    http://weather.uwyo.edu/upperair/sounding.html
    http://www.esrl.noaa.gov/psd/cgi-bin/data/timeseries/timeseries1.pl
    http://www.humidity-calculator.com/index.php

    complications to consider -
    Smaller droplets are in equilibrium at higher vapor pressures – the surface energy change caused by the curvature of the surface causes small droplets to require supersaturation for formation and growth; if the water vapor pressure is below that required for a small droplet, and above that required for a larger droplet, mass will transfer from the smaller to the larger by evaporation and condensation.
    The moist adiabatic lapse rate varies depending on the mass of water available to supply heat by phase change, therefore varies with temperature and pressure(altitude).
    Orographic and frontal lift/sinking, and momentum of moving masses of air sum with convective lift. The convective + momentum lift of tropical thunderstorms probably plays a role in injecting water into the stratosphere – http://svs.gsfc.nasa.gov/vis/a000000/a000800/a000831/a000831.mpg
    Precipitation moves water and latent cool of melting/evaporation down in the atmosphere.
    Winds have a significant influence on ocean evaporation, by removing the high humidity near surface layer, increasing the evaporative surface by ripple/wave formation, and creating spray(large highly curved surfaces) at high wind speeds. And surface winds are turbulent at a wide range of scales – spend a day sailing with an experienced skipper (like me &;>) and have him show you how to visualize the wind variations by ripple patterns. Also, since the troposphere is only ~ 10 km thick, turbulence at 1km scales is 3 dimensional, but at 100km plus, the flow is approximately 2 dimensional. large scale flow can couple into smaller scale turbulence – http://paranoicmrbrain.files.wordpress.com/2008/06/72.jpg http://www.colorado.edu/geography/class_homepages/geog_3251_sum08/07_rotor_clouds.jpg

    Comment by Brian Dodge — 10 Mar 2010 @ 7:03 PM

  201. I was thinking about the mechanisms that remove CH4 from the atmosphere, and the recent decline in stratospheric water vapor noted by Solomon et al, and it occurred to me that increased GCRs might increase conversion of water vapor to hydroxyl radicals, removing water and methane from the stratosphere. I downloaded some CH4 data from CDIAC and some CR data from Oulu, and plugged it into my trusty(buggy and crash prone) Appleworks spreadsheet. The data only covers 8/93 to 3/2009. I normalized the data by the monthly averages for the first 12 years to remove annual cyclic variation, and got some interesting results. The flat portion of the methane concentration corresponds to low, not high CR levels, and there appears to be a threshold effect. It’s probably spurious correlation. Solar UV varies inversely with CR, and photodissociation may well dominate, which could explain the flat CH4 when the CR was low/UV was high. I haven’t found an easily accessible monthly solar UV dataset to plug into my spreadsheet yet.
    Graphs are at http://www.imagenerd.com/uploads/gcrvsch4-TfMuw.jpg – Pretty weird, eh? Any thoughts?

    [Response: There are definitely feedbacks associated with the hydrogen that methane carries. It's a greenhouse gas, for one. I don't remember what the balance of water vapor in the stratosphere is, between atmospheric mixing, cloud convection overshoot, and methane, but it's definitely an issue. Just for fun: Lovelock calls methane little "hydrogen balloons", carrying out the Gaian task of carrying methane to the stratosphere, letting the hydrogen escape to space, building up oxidation of the Earth. David]

    Comment by Brian Dodge — 10 Mar 2010 @ 11:24 PM

  202. A radical mechanism for methane buildup.
    Two scientists suggest a link between the atmospheric buildup of methane–an important greenhouse gas–and a shortage of a highly reactive molecule called the hydroxyl radical hydroxyl radical: see hydroxide. . Their surprising finding indicates that hydroxyl hydroxyl /hy·drox·yl/ (hi-drok´sil) the univalent radical OH.
    hy·drox·yl
    n.
    The univalent radical or group OH, a characteristic component of bases, certain acids, phenols, alcohols, carboxylic depletion in the Northern Hemisphere is about twice as severe as previously believed.
    http://www.thefreelibrary.com/A+radical+mechanism+for+methane+buildup-a010426291

    The major removal mechanism of methane from the atmosphere involves radical chemistryRadical (chemistry)In chemistry, radicals are atoms, molecules, or ions with unpaired electrons on an otherwise open shell configuration. These unpaired electrons are usually highly reactive, so radicals are likely to take part in chemical reactions…; it reacts with the hydroxyl radicalHydroxyl.
    The hydroxyl radical, OH·, is the neutral form of the hydroxide ion . Hydroxyl radicals are highly reactive and consequently short-lived; however, they form an important part of radical chemistry…(·OH), initially formed from water vapor broken down by oxygen atoms that come from the cleavage of Ozone or trioxygen is a simple triatomic molecule, consisting of three oxygen atoms. It is an allotrope of oxygen that is much less stable than the diatomic O2.
    Ground-level ozone is an air pollutant with harmful effects on the respiratory systems of animals…by ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than x-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV…radiation:This reaction in the troposphere. The troposphere is the lowest portion of Earth’s atmosphere. It contains approximately 75 percent of the atmosphere’s mass and 99 percent of its water vapor and aerosols….gives a methane lifetime of 9.6 years.
    Two more minor sinks are soil sinks (160 year lifetime) and stratospheric loss by reaction with ·OH, ·Cl and ·O1D in the stratosphere (120 year lifetime), giving a net lifetime of 8.4 years. Oxidation of methane is the main source of water vapor in the upper stratosphere (beginning at pressure levels around 10 kPaKPAKPA may refer to:* Kenya Ports Authority* Kilopascal , a unit of pressure* Known-plaintext attack, a method of cryptanalysis* Korean People’s Army* The Kosovo Property Agency* Also refers to the Montagnard name meaning “straight”….).The methyl radical formed in the above reaction will, during normal daytime conditions in the troposphere, usually react with another hydroxyl radical to form formaldehydeFormaldehydeFormaldehyde is a chemical compound with the formula CH2O. It is the simplest aldehyde. Formaldehyde also exists as the cyclic trimer trioxane and the polymer paraformaldehyde. It exists in water as the hydrate H2C2. Aqueous solutions of formaldehyde are referred…. Note that this is not strictly oxidative pyrolysisPyrolysisPyrolysis is the chemical decomposition of condensed organic substances by heating. The word is coined from the Greek-derived elements pyro “fire” and lysys “decomposition”….as described previously. Formaldehyde can react again with a hydroxyl radical to form carbon dioxideCarbon dioxideCarbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. It is a gas at standard temperature and pressure and exists in Earth’s atmosphere in this state…and more water vapor. Note that sidechains in these reactions may interact with nitrogenNitrogenNitrogen is a chemical element that has the symbol N and atomic number 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless and mostly inert diatomic gas at standard conditions, constituting 78% by volume of Earth’s atmosphere.Many industrially important…compounds that will likely produce ozoneOzoneOzone or trioxygen is a simple triatomic molecule, consisting of three oxygen atoms. It is an allotrope of oxygen that is much less stable than the diatomic O2. Ground-level ozone is an air pollutant with harmful effects on the respiratory systems of animals…, thus supplanting radicals required in the initial reaction.
    http://www.absoluteastronomy.com/topics/Atmospheric_methane

    However, much of the methane released from permafrost may remain in the atmosphere longer, due to OH depletion. The more methane there is to be oxidized, the more chance there is of OH depletion, and the longer it will take for methane to oxidize.
    http://knol.google.com/k/sam-carana/the-threat-of-methane-release-from/7y50rvz9924j/32#

    [Response: This is already taken into account in metrics like GWP, but is not as big an effect as you might think. We discussed this in Schmidt and Shindell (2003). - gavin]

    Comment by prokaryote — 11 Mar 2010 @ 2:30 AM

  203. In 2008 Shakovha wrote,

    The total value of ESS carbon pool is, thus, not less than 1,400 Gt of carbon. Since the area of geological disjunctives (fault zones, tectonically and seismically active areas) within the Siberian Arctic shelf composes not less than 1-2% of the total area and area of open taliks (area of melt through permafrost), acting as a pathway for methane escape within the Siberian Arctic shelf reaches up to 5-10% of the total area, we consider release of up to 50 Gt of predicted amount of hydrate storage as highly possible for abrupt release at any time. That may cause 12-times increase of modern atmospheric methane burden with consequent catastrophic greenhouse warming.

    http://www.cosis.net/abstracts/EGU2008/01526/EGU2008-A-01526.pdf

    Seems pressing, like being trapped in a Prius at 100mph.

    [Response: This is the most specific proposal for getting a lot of methane out that I've seen. If 50 Gton of methane did all come out within a few years it would have a radiative forcing of about 4 W/m2, according to MODTRAN for what that's worth (single location, not counting the indirect effects of methane chemistry, old model, etc.) That's big but so are volcanic eruptions, which can be -5 or so W/m2. The methane would oxidize to CO2 in about a decade, at which point 50 Gton C is certainly a lot of C, five years' emission worth, but it's not like a game changer exactly. David]

    Comment by jcrabb — 11 Mar 2010 @ 6:23 AM

  204. Thanks everyone for your help. I will do some more reading for a while, including spending some more time on this Raymond Pierrehumbert paper, which seems to be a very good summary of what is going on.

    Comment by Blair Dowden — 11 Mar 2010 @ 7:52 AM

  205. Re
    http://www.realclimate.org/index.php/archives/2010/03/arctic-methane-on-the-move/comment-page-3/#comment-165280

    Slow moving storms -

    It’s a bit more complicated than that, actually. On scales and for conditions where geostrophy is a good approximation, vertical wind shear tends to be proportional to a horizontal temperature gradient and inversely proportional to the coriolis parameter f (which is proportional to the sine of the latitude).

    A reduction in the temperature gradient makes the geostrophic wind more similar; but this could either involve a change in wind above or the opposite change in wind below.

    At some latidudes, in some seasons, in the zonal average, the meridional temperature gradient will decrease with global warming. However, in the upper troposphere, there is a general tendency for the pole-equator temperature gradient to increase.

    In growing baroclinic waves via counter-propogating mutually-amplifying Rossby waves (developing synoptic-scale low pressure systems, and highs too, though there is some assymetry), the wave pattern moves at some intermediate velocity between the upper and lower-level Rossby waves; thus, air blows through the systems from east to west in low levels and from west to east at upper levels, except when the systems are strong enough for the wave’s wind field to match and exceed the system-relative background-state wind; in that case the wind blows from east to west around a low only on the low’s cold side, … etc. This activity ultimately tends to horizontally-concentrate westerly (west-to-east) momentum at upper levels into a westerly jet but also transfer some westerly momentum down to the surface… (while it mixes heat downgradient horizontally and also transports heat upward). But there are variations in that pattern such as in NAM/SAM annular mode variations, and … a bunch of other stuff …

    (In the absence of such activity, considering a hemispheric steady-state Hadley cell*, westerly momentum would build up in the atmosphere acting on suruntil surface winds at high latitudes became westerly in spite of the equatorward motion – this would require some ageostrophic westerly wind component that would be driven by momentum transport from above… Of course, the extent of a Hadley cell, depending on how much mixing of momentum is allowed across streamlines in the meridional plane, is limited by conservation of angular momentum and also that the temperature at the poles can’t dip below absolute zero;… might be a bit more to it than that but anyway…)

    Comment by Patrick 027 — 11 Mar 2010 @ 12:56 PM

  206. “at some intermediate velocity between the upper and lower-level Rossby waves;”
    I meant the wind at those levels

    “This activity ultimately tends to horizontally-concentrate westerly (west-to-east) momentum at upper levels into a westerly jet but also transfer some westerly momentum down to the surface… (while it mixes heat downgradient horizontally and also transports heat upward). ”
    - Depending on intial conditions (if the storm track is displaced from the maximum in the westerlies, it may push the westerlies away ?)
    - Some of the effect on the temperature gradient may be counterintuitive (depending on what level of understanding your intuition is based on, of course). (PS based on the Ferrel cell (a consequence of this storm track activity), an initial guess might be that the storm activity produces an enhanced temperature gradient to it’s cold side at the surface; in that case, the storm track might migrate poleward; then lack of mixing equatorward of that would give rise to a second storm strack that would migrate poleward, taking the place of the first as it dies out. A nice simple scenario but I’m guessing incorrect even in a simplified world (?) (because inflow towards the belt of low pressure produced by storm track activity occurs after the lows become cold-core features at the surface (?)… the surface cold fronts meanwhile have gone equatorward, … well it gets complicated)…)

    Comment by Patrick 027 — 11 Mar 2010 @ 1:23 PM

  207. Why focus so much on the troposphere and stratosphere, when considerung methane uptake?

    An interesting feature is that the summer mesopause is cooler than the winter. This is sometimes referred to as the mesopause anomaly. It is due to a summer-to-winter circulation giving rise to upwelling at the summer pole and downwelling at the winter. Air rising will expand and cool resulting in a cold summer mesopause and conversely downwelling air results in compression and associated increase in temperature at the winter mesopause. It should be noted that in the mesosphere the summer-to-winter circulation is due to gravity wave dissipation, which deposits momentum against the mean east-west flow resulting in a small north-south circulation
    http://en.wikipedia.org/wiki/Mesopause

    Trends of mesospheric water vapor due to the increase of methane – A model study particularly considering high latitudes

    This Lyman-α flux values are used to determine the water vapor dissociation rate. The solar influence on the water vapor mixing ratio is insignificant at about 80 km within the NLC area but it becomes increasingly more important with growing altitudes. The rising water vapor concentration reduces the mesospheric ozone due to higher concentrations of the hydrogen radicals. This fact causes a positive feedback between both constituents above about 65 km. The dissociation of smaller amounts of ozone entails the production of less amounts of O(1D) destroying a smaller quantity of water vapor. The effect is most pronounced in the vicinity of the daytime secondary ozone maximum around an altitude of 85–90 km where the relative increase of the water vapor mixing ratio is strongest.
    http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V3S-4M6SG8R-2&_user=10&_coverDate=12%2F31%2F2006&_rdoc=1&_fmt=high&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1245861860&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=b772ea9d9b5fd7c478760357e39cc822

    Mesosphere-stratosphere transport during Southern Hemisphere autumn deduced from MIPAS observations
    http://cat.inist.fr/?aModele=afficheN&cpsidt=21376265

    Methanogenesis, Mesospheric Clouds, And Global Habitability
    http://geo.arc.nasa.gov/sgp/aero/aerocloud3.html

    Comment by prokaryote — 12 Mar 2010 @ 5:38 AM

  208. The emphasis on the short half life of methane seems a bit disingenuous to me. The stat cited is that methane has 23 times the GW power of CO2. But that is over a century. So even if this stuff is released over the period of a century, each molecule will have 23 times the power of a CO2 molecule.

    And as jcrabb noted at #103 above, Shakhova puts the amount of carbon in these stores at 1,400 Gts.

    Since David presented this is a very potent threat in his book, either he was overstating his case then or is understating it here. I think when it comes down to it the emotional impact of knowing we are at the precipice is too much for all of us. There are many reasons that many people have been unable to accept the overwhelming evidence of AGW, but emotional is a basic one, as it now seems to be here.

    We are all denialists now.

    [Response: The global warming potentials you're referring to are weighted according to time, with 100 years being one of the time horizons. But the lifetime of methane in the air is about a decade, no disingenuousness intended. David]

    Comment by wili — 12 Mar 2010 @ 9:03 AM

  209. “208
    wili says:
    12 March 2010 at 9:03 AM

    The emphasis on the short half life of methane seems a bit disingenuous to me. The stat cited is that methane has 23 times the GW power of CO2. But that is over a century. So even if this stuff is released over the period of a century, each molecule will have 23 times the power of a CO2 molecule.”

    Over that time.

    The numbers here are made up for illustration purposes and I don’t have a calculator to hand…

    1000 Methane Molecules. 100 times the power of CO2 but halves in volume every year.

    Year 1: 100,000
    Year 1 + 2: 100,000 + 50,000
    Year 1 + 2 + 3: 100,000 + 50,000 + 25,000

    Total effect: 200,000 units.

    1000 CO2 Molecules 1 times the power of CO2 but halves in volume every 200 years.

    Year 1-200: 200,000
    Year 1-400: 300,000

    Total effect: 400,000 units.

    Ergo, over 5 years, Methane is much greater than CO2. Over 500 years, CO2 is much greater than Methane.

    Comment by Completely Fed Up — 12 Mar 2010 @ 10:22 AM

  210. PS that isn’t how it’s done, but it shows the shape of the reasoning.

    [Response: It does indeed. David]

    Comment by Completely Fed Up — 12 Mar 2010 @ 10:23 AM

  211. Just read this via Slashdot: http://www.inhabitat.com/2010/03/11/china-developing-combustible-ice-as-new-energy-source/

    China: 90 years worth of energy from methane-ice, apparently. No idea what to believe. That story says it’s ‘better than letting it release through melting’ but would that be true? Burning it will produce co2 which is longer-lasting – and how much co2 would we be talking about from this project?

    [Response: A reporter asked me about this idea the other day, whether extracting it and burning it is better than letting it release directly. I guess there was a line in a many-authored paper I was on to this effect. But generally the methane that's escaping to the air, if it's from hydrate at all and not from decomposing peat, is disseminated through permafrosts and is not the same stuff that the oil company guys want to go after. So I told the guy I didn't believe in methane extraction as a mitigation option against hydrate melting, that sounds like oil company bs to me. David]

    Comment by Dan Olner — 12 Mar 2010 @ 10:24 AM

  212. The petroleum companies are hoping to go after stable deepsea hydrate formations in fairly pure forms, it looks like from a quick search
    http://scholar.google.com/scholar?q=mining+methane+hydrate+outcrop

    for example this: US DOE publication 2008
    Hydrate Production through CO2-CH4 Exchange
    Methane Hydrate Newsletter Fall 2008, (US Dep’t of Energy publication)
    By ConocoPhillips – University of Bergen Hydrates Team

    Scholar finds it here:
    http://rasmus.uib.no/People/nglbh/GANS/pdf/HMNewsFall08.pdf

    As David says, those are not currently our concern for atmospheric release.

    Comment by Hank Roberts — 12 Mar 2010 @ 11:55 AM

  213. The first point obviously would be: is the methane going to be released anyway? “Extraction” seems like a problematic concept in this regard! If you must “extract” it, how imminent is the putative emission?

    OTOH, if emission is inevitable and there’s an option to burn, then logic says do it: you have CO2 with a greenhouse-intense “early life,” or you have CO2 without it. Clearly the latter is marginally better–especially if the energy produced displaced coal-fired energy from the mix.

    Comment by Kevin McKinney — 13 Mar 2010 @ 12:01 AM

  214. At #208, David kindly responded to my (doubtless hopelessly ignorant) inquiry about the relationship between methane lifespan in the atmostphere and its power as a GHG with the following:

    “The global warming potentials you are refering to are weighted according to time, with 100 years being one time horizons. But the lifetime of methane in air is about a decade….”

    So now I, as a non-expert, am confused. I assumed that the lifetime of methane in the atmosphere was a kind of belljar curve with a longish tail. That tail means that there is enough methane, even after a century, in the atmosphere for whatever quantity initially released to have about 23-25 times the gh potential of the same amount of CO2 (over the same time frame).

    But the same amount of methane,as I have understood it, would be largely still present in the atmosphere in say seven years after release, at which point it would represent well over 100 times the gh potential of CO2 over that same time frame.

    Is this just way off? (I’m afraid the Fedup illustration did not illuminate much for me–what, by that model is the warming potential of methane over the period of a century?)

    [Response: Looks like you have the basic idea right. Since CH4 decays at a much faster rate than CO2, it's GWP relative to CO2 will decline as the reference time frame increases (because GWP is calculated for an equivalent amount of gas): from 72 over 20 years to 7.6 over 500 years. See the IPCC AR4 WG1 report, section 2.10 and Table 2.14.--Jim]

    I am doubtless missing something basic here. Sorry for my relative density ;-}

    Comment by wili — 13 Mar 2010 @ 2:53 AM

  215. “1000 Methane Molecules. 100 times the power of CO2 but halves in volume every year.
    ….
    Total effect: 200,000 units.

    1000 CO2 Molecules 1 times the power of CO2 but halves in volume every 200 years.

    Total effect: 400,000 units.
    PS that isn’t how it’s done, but it shows the shape of the reasoning.

    Yes it does but your numerical application is wrong. If methane had 100 times the warming power but the decay time is 200 times smaller (one year instead of 200), then it has indeed a 100/200 = 1/2 warming power integrated over its lifetime, what your calculation confirms. But if the right number is 25, with a life time 10 times smaller, it means that the instantaneous warming power is more 250 times , divided by 10 for the lifetime. Doesn’t change the fact that methane from arctic is only a few percent of a global 20 % of methane contribution to warming, of course.

    Comment by Gilles — 13 Mar 2010 @ 6:09 AM

  216. Wili: “I assumed that the lifetime of methane in the atmosphere was a kind of belljar curve with a longish tail. ” This is not true. Methane’s exponential decay means that there is very very little methane left after a century – effectively zero. (this is unlike CO2, which has a very complicated lifecycle, and therefore while given a pulse of emissions, the concentration of CO2 has a fast initial decay some percentage hangs around for thousands of years).

    The actual definition of the GWP is the total sum of radiative forcing over the century, not the amount of radiative forcing at the end of the century. So this is an area under the curve problem.

    If you go look at the AR4 WGI report that Jim mentioned, you’ll find that the instantaneous forcing of CH4 is 37 compared to 1.4 for CO2 – per ppb in the atmosphere. Correct for mass (44/16), and you get about 73. So a ton of methane has 72 times the effect after 1 second as a ton of CO2. Therefore, the “1 second GWP” is about 72. As time passes, the ratio of CO2 left to CH4 left increases, and so the relative radiative forcing of CH4 decreases… but since the GWP is the integral over time, you are adding together the time that CH4 was 72 times CO2 to the time that CH4 was 20 times CO2 to the time when CH4 was 0 times CO2 – so at 100 years, even though CH4 is about 0 times CO2, the initial period is still being added in.

    (note that there are some other corrections in the GWP unique to CH4 because its ozone and strat. water vapor effects are added in – I think it is a rough times 1.4 multiplier)

    -Marcus

    Comment by Marcus — 13 Mar 2010 @ 6:19 AM

  217. wili,
    First, a nit, since it is clear that you are trying very hard to understand, I’d call you “learning” rather than “ignorant”.

    Remember that because there is so much less CH4 in the atmosphere, and because CH4 is absorbing where H20 and CO2 are not, that it is taking a bite out of a virgin chunk of the IR spectrum.

    http://en.wikipedia.org/wiki/File:Atmospheric_Transmission.png

    So a large influx of CH4 causes a large imbalance and rapid warming. However, since the methane has a short lifetime, it has decayed to well under a quarter of its initial abundance before the planet has had time to reach equilibrium again. So, essentially when you look at the GWP, if I understand it you are looking at the area under the 100 year curve and dividing by 100 years. (More or less corrrect, Jim?)

    Comment by Ray Ladbury — 13 Mar 2010 @ 8:32 AM

  218. Thanks even more for all the responses. But now I’m a bit more confused on one point. Jim says the GW potential of methane over 20 years is 72 times CO2, but Marcus gives the same multiple for the GWP during the first second it is released. I can’t see how these could both be right, but perhaps I’m missing something basic?

    [Response: Don't trust an ecologist to educate you on greenhouse gas forcings, but here's my explanation. Marcus was talking about the instantaneous forcing ratio (CH4 to CO2) per unit weight, which incorporates radiative efficiency and molecular weight differences, and is thus about (370/14)*(44/16) = 73. But the GWPs are calculated over various intervals (20, 100, 500 years), and these incorporate the indirect effects of CH4 on O3 and stratospheric H2O radiative forcing, which are not included in the instantaneous calcs. Therefore the CH4 GWPs at the 3 time points are higher than would otherwise be. But I could be wrong.--Jim]

    The fact Jim pointed out that methane still has seven times the GHP of CO2 even after half a millennium again leads me to think that release of any significant portion of the 1,400 gigatons of the stuff over that time period may well be possible and dangerous.

    Still trying to make sense of the calming tone of the lead post given what looks to be very ominous data. Perhaps David or others could say how long they think it would take for a significant amount of methane hydrate (is the term ‘clathrate’ still used?) might be released–multiple millennia?

    Another thing, is there a point at which methane’s GWP dips below that of CO2, and what point would that be?

    Or, since it mostly decays into CO2, is the GWP of that produced CO2 figured in so it would never drop below the CO2 GWP number?

    Thanks again in advance for informative responses, and apologies again if I am missing the obvious.

    Comment by wili — 13 Mar 2010 @ 11:36 AM

  219. David’s response to 169 Milan, to the possibility that methane feedback was a cause of the PETM warming event was

    Or carbon release from peats, or soil carbon, or biomass, or the ocean somehow-like-it-did-during-the-glacial-cycles.
    Methane is not the only game in town.

    My notes from a long conversation with a leading climate modeler contain this

    PLAN B

    There should be a plan B for climate change if reducing emissions of CO2 cannot be effected soon enough. This would take more seriously the effects of pathways with shorter timescales than CO2, such as methane, ozone (NOx as a precursor), nitrous oxide and black carbon. Plan B should also consider geoengineering. Sulphate looks best but Salter’s boats have a regional effect that must be closely monitored.

    It may be necessary to accept ocean acidification caused by rising CO2 levels. It should be remembered that CO2 does have a fertilising effect on plant growth.

    Plan B is not a substitute for addressing CO2 but shorter term measures may become necessary.

    Air travel is not a large part of the climate problem. Livestock is a big issue.

    The climate feedbacks that David mentions increase the need for a plan B. I know of no policy makers aware of this issue.

    In the UK there is a standard, PAS2050, which specifies how products and activities should be assessed to measure their impact on climate change. But it’s measurement is aimed at a 100 year time-scale. It is of little use for Plan B. A PAS2050(Plan B) is required. But not much easily digestible literature on climate is available to help the climate change bean counters. The best so far is Unger et. al. “Attribution of climate forcing to economic sectors”
    (http://pubs.giss.nasa.gov/docs/notyet/inpress_Unger_etal.pdf).

    The limitation of this paper (for climate bean counting) is the aggregation of climate forcing agents into broad economic sectors. Finer detail is needed. We should now not just the impact of road transport over time but the difference between different types of road transport – diesiel, electric &etc.

    I am looking forward to some literature that can help, ideally with the a graph of the major climate forcing agents and their effects over at least a century to give the climate bean counters something to work on.

    Comment by Geoff Beacon — 13 Mar 2010 @ 2:35 PM

  220. There is a paper by Shindell et al., “Improved Attribution of Climate Forcing to Emissions“,
    http://www.sciencemag.org/cgi/content/abstract/326/5953/716

    This paper argues that methane is more potent than previously realised due to the interaction with black carbon. The paper gives a revised Global Warming Potential for methane measured over 100 years as 33. This is an increase of over 30% compared to the value of 21 given in the IPCC Second Assessment Report used for the Kyoto Protocol. Over 20 years. Shindell et al. calculate this GWP to be 105. If this measure were used the climate impact of methane (e.g. for Plan B above), it would be 5 times the value agreed at Kyoto.

    This is important in assessing the impact of animal husbandry, particulary for cattle and sheep. Are Shindell et. al. right?

    [Response: Of course we are! ;) - gavin]

    Comment by Geoff Beacon — 13 Mar 2010 @ 2:50 PM

  221. Re: 220 Geoff Beacon 13 March 2010 at 2:50 PM

    With mention of Kyoto, if it does carry into various other indices, wonder how this is going to translate into e.g. the AGGI index? A simulation of the before and after per end of 2008 would be nice to see.

    Comment by Sekerob — 13 Mar 2010 @ 3:26 PM

  222. G Beacon. Thanks for pointing out this article. Over 100 times CO2 GWP over a 20 year interval is quite a stunning figure. Do they estimate it for 5, 7, or 10 year intervals?

    On a side note, I don’t understand why you are so dismissive of the role of air travel in GW. Of course it is small compared to coal burning for electricity or meat eating–most of the world uses electricity and eats meat, while relatively few regularly fly.

    But that doesn’t mean that it is benign as an activity, or that it isn’t a huge part of any individuals carbon foot print who flies more than once or twice a year. Am I missing something? Or is the rationalization it looks like.

    [Response: GWP on very short periods is not a useful thing to calculate because the climate system integrates GHG forcings over decades. Even 20 years is a bit of stretch. 50 or 100 year periods are the most relevant for what will actually happen. - gavin]

    Comment by wili — 13 Mar 2010 @ 7:15 PM

  223. Re GWPs -

    The decay rate of instantaneous forcing from a unit of emission at one time can change as the compositions and climates of the atmosphere and ocean change, but setting that issue aside (or using an averaged effect for each type of emission over some time period, given some expected scenario):

    The GWP per unit emission, multiplied by the emission rate, gives a GWP per unit time, with units of radiative forcing (or that relative to a standard); if the emission rate is constant over time, then the radiative forcing is approached that is proportional to the GWP per unit emission * emission rate.

    The GWP of methane depends on whether the methane is of fossil C or not, or if it is not fossil C, if it is part of a net removal of C from biomass or soil. If it is either of those, then the CO2 from methane adds to the GWP.

    Comment by Patrick 027 — 13 Mar 2010 @ 7:58 PM

  224. “if the emission rate is constant over time, then the radiative forcing is approached that is proportional to the GWP per unit emission * emission rate.”

    Oops, that’s only if the time period is long enough for the instantaneous radiative forcings of the oldest emissions to have decayed to near zero.

    Comment by Patrick 027 — 13 Mar 2010 @ 8:01 PM

  225. Wili, the material your questions generated has been very informative. Thanks, and please do keep it up.

    Re #s 205/6: Patrick, see last week’s Nature cover article on Pliocene tropical cyclones, one implication of the circulation reorganization we can look forward to if CO2 stays anywhere close to current levels. Also see various recent PRISM papers for details on the reorganization.

    Re #219: Geoff, it’s worth mentioning that we’ll already be in pretty bad shape if sulfate injection starts sounding like an attractive option.

    Re #222 response: Gavin, wouldn’t that integration lag mean we’d be looking at a noticable tropospheric warming pulse in the first decade or so? Any idea what that would be based on the methane release Shakhova postulates?

    Comment by Steve Bloom — 13 Mar 2010 @ 9:43 PM

  226. Gavin’s response to 222.wili is

    GWP on very short periods is not a useful thing to calculate because the climate system integrates GHG forcings over decades. Even 20 years is a bit of stretch. 50 or 100 year periods are the most relevant for what will actually happen.

    If I understand correctly Myles Allen’s “Towards the trillionth tonne” has an emphasis on “the accumulated total of long-lived GHGs over time” and its “all-important peak”. The timing of the peak concentration of greenhouse gases is more important than it’s timing. (The quotations are from the UK Committe on Climate Change)

    On this analysis when the climate is near the “all important peak” the measurement of short term species over short time-scales will become important.

    But I infer from Gavin’s response that he expects no serious unexpected net positive feedback in the short term. But some feedbacks are happening already with unexpected speed. Peter Wadhams tells me:

    The case of Arctic ice is somewhat of a tipping point since the open water created during summer warms up, to about 5C at present, and this slows down the subsequent autumn freeze up, giving less winter growth. The area of multiyear ice is also shrinking to the point where almost the whole ice cover will be susceptible to summer melt. It may grow back a little in a cold winter but in my view it can never get back to its original situation of, say, 40 years ago. In this sense it has passed through a tipping point

    This may not be the clathrate gun but it has been happing sooner than expected.

    P.S. Sorry I didn’t notice Gavin as et.al.

    Comment by Geoff Beacon — 14 Mar 2010 @ 10:24 AM

  227. Is there any research done around what might become a ‘tipping event’ for our Earth. My thoughts is in the direction of methane being that sliver that tips the climate for good. We have had earlier very sharp turnings of the Earths climate haven’t we, like happening over just decades.

    And no matter what we say here we can’t really say how much methane that’s getting loose for the moment. There are all kind of ‘relations/forcings’ building up the climate we see, and i expect them to be able to feed on each other and increase. If that is right, then it isn’t the slow build up that should worry us but the short time ‘rush’ we might get, tipping our Earth irrecoverably.

    So that’s what I’m wondering about. Have there been any experiments, or theoretical studies over what might suffice for creating a ‘tipping point’ for our Earth.

    Comment by Yoron — 14 Mar 2010 @ 3:00 PM

  228. Thanks again to one and all for great and very pertinent info.

    Geoff at #226 wrote, “The timing of the peak concentration of greenhouse gases is more important than it’s timing.”

    Is there a typo here? I’m trying to understand what you are saying as it sounds quite significant, but I can’t quite follow this.

    I probably won’t post much more here, but to me, as a long term thinker, even if all the sea bottom methane turned to CO2 before it reached the atmosphere, and even if this happened over millennia, if a significant portion of the total did so through the now multiple feedbacks, this would both strengthen and lengthen the warming even, making it all that much harder on the planetary life systems.

    Not good news.

    Of course, the rational response to any of these scenarios is to reduce our added forcing as quickly as possible. But we do not seem capable, collectively, of such a rational response. Do what you can individually and locally, while still putting pressure on national leaders.

    Best to all,
    john “wili” harkness

    Comment by wili — 15 Mar 2010 @ 11:31 AM

  229. Re wili 228 – from the context, I’m guessing what was meant was that the timing of the instaneous radiative forcing is more directly important than the timing of the emissions. The later would generally peak earlier than the former (although a sudden-enough drop could increase the forcing in the short term if there is an associated drop in some aerosol emissions – that depending on the emission source).

    Comment by Patrick 027 — 15 Mar 2010 @ 12:37 PM

  230. Re Steve Bloom 225 – sounds interesting, thanks!

    Comment by Patrick 027 — 15 Mar 2010 @ 12:39 PM

  231. 228 wili. Thanks it should have read.

    The level of the peak concentration of greenhouse gases is more important than it’s timing.

    Comment by Geoff Beacon — 16 Mar 2010 @ 5:22 AM

  232. Thanks for the clarification, Geoff.

    If I can task the patience of the community one more time: I note that on sites like http://www.esrl.noaa.gov/gmd/ccgg/iadv/ they indicate levels for CH4c13 at some locals as well as for CH4. Does this isotope tell us about the origins of the methane? Do higher relative concentrations of CH4c13 in the mix indicate a higher or lower level of methane from current biological activity? Or is it an indicator for something else?
    Thanks again.

    Comment by wili — 16 Mar 2010 @ 8:20 AM

  233. What’s the scientific evidence show about methane hydrate dissociation in the Arctic or anywhere oil and gas wells have been drilled?

    MBARI’s Dr. Charles Paull, did some work for lots of years in the Arctic and claimed that ch4 could only form where there was freshwater, co2 and methane from decayed material. The hydrates, he said could not be formed in salt water. What was interesting is that these hydrates were dissociating more rapidly than anyone had estimated due to wraming of the tundra and permafrost. This was occuring in many of the locations where oil and gas wells were numerous.

    What’s the consequence? What do we know about the extent to which the oil industry uses fresh water to pressurize wells and leaves it down there for decades. How much? From where does it come? Who loses the water?

    Comment by PotomacOracle — 31 Mar 2010 @ 8:16 PM

  234. Great post, I would suggest that you make it a bit handier to share this to some social media sites, throw up a big add to twitter button or something in a few places that are obvious. No sense in making it too much work to add your stuff. Also, I really like your comment layout here, is it the default setup for your theme or did you customize it?

    Comment by uop online — 2 Apr 2010 @ 11:50 PM

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