RealClimate logo


Arctic Methane on the Move?

Filed under: — david @ 6 March 2010 - (Italian)

Methane is like the radical wing of the carbon cycle, in today’s atmosphere a stronger greenhouse gas per molecule than CO2, and an atmospheric concentration that can change more quickly than CO2 can. There has been a lot of press coverage of a new paper in Science this week called “Extensive methane venting to the atmosphere from sediments of the East Siberian Arctic Shelf”, which comes on the heels of a handful of interrelated methane papers in the last year or so. Is now the time to get frightened?


No. CO2 is plenty to be frightened of, while methane is frosting on the cake. 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 is CO2. Then you figure out that the accelerator has also jammed, so that by the time you hit the truck in front of you, you will be going 90 miles per hour instead of 60. This is methane. Is now the time to get worried? No, you should already have been worried by the broken brake pedal. Methane sells newspapers, but it’s not the big story, nor does it look to be a game changer to the big story, which is CO2.

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

For some background on methane hydrates we can refer you here. This weeks’ Science paper is by Shakhova et al, a follow on to a 2005 GRL paper. The observation in 2005 was elevated concentrations of methane in ocean waters on the Siberian shelf, presumably driven by outgassing from the sediments and driving excess methane to the atmosphere. The new paper adds observations of methane spikes in the air over the water, confirming the methane’s escape from the water column, instead of it being oxidized to CO2 in the water, for example. The new data enable the methane flux from this region to the atmosphere to be quantified, and they find that this region rivals the methane flux from the whole rest of the ocean.

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.

Westbrook et al 2009, published stunning sonar images of bubble plumes rising from sediments off Spitzbergen, Norway. The bubbles are rising from a line on the sea floor that corresponds to the boundary of methane hydrate stability, a boundary that would retreat in a warming water column. A modeling study by Reagan and Moridis 2009 supports the idea that the observed bubbles could be in response to observed warming of the water column driven by anthropogenic warming.

Another recent paper, from Dlugokencky et al. 2009, describes an uptick in the methane concentration in the air in 2007, and tries to figure out where it’s coming from. The atmospheric methane concentration rose from the preanthropogenic until about the year 1993, at which point it rather abruptly plateaued. Methane is a transient gas in the atmosphere, so it ought to plateau if the emission flux is steady, but the shape of the concentration curve suggested some sudden decrease in the emission rate, stemming from the collapse of economic activity in the former Soviet bloc, or by drying of wetlands, or any of several other proposed and unresolved explanations. (Maybe the legislature in South Dakota should pass a law that methane is driven by astrology!) A previous uptick in the methane concentration in 1998 could be explained in terms of the effect of El Niño on wetlands, but the uptick in 2007 is not so simple to explain. The concentration held steady in 2008, meaning at least that interannual variability is important in the methane cycle, and making it hard to say if the long-term average emission rate is rising in a way that would be consistent with a new carbon feedback.

Anyway, so far it is at most a very small feedback. The Siberian Margin might rival the whole rest of the world ocean as a methane source, but the ocean source overall is much smaller than the land source. Most of the methane in the atmosphere comes from wetlands, natural and artificial associated with rice agriculture. The ocean is small potatoes, and there is enough uncertainty in the methane budget to accommodate adjustments in the sources without too much overturning of apple carts.

Could this be the first modest sprout of what will grow into a huge carbon feedback in the future? It is possible, but two things should be kept in mind. One is that there’s no reason to fixate on methane in particular. 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. 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.

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 time scale that is faster than the decadal lifetime of methane in the air. So far no one has seen or proposed a mechanism to make that happen.


References

Dlugokencky et al., Observational constraints on recent increases in the atmospheric CH4 burden. GEOPHYSICAL RESEARCH LETTERS, VOL. 36, L18803, doi:10.1029/2009GL039780, 2009

Reagan, M. and G. Moridis, Large-scale simulation of methane hydrate dissociation along the West Spitsbergen Margin, GEOPHYSICAL RESEARCH LETTERS, VOL. 36, L23612, doi:10.1029/2009GL041332, 2009

Shakhova et al., Extensive Methane Venting to the Atmosphere from Sediments of the East Siberian Arctic Shelf, Science 237: 1246-1250, 2010

Shakhova et al., The distribution of methane on the Siberian Arctic shelves: Implications for the marine methane cycle, GEOPHYSICAL RESEARCH LETTERS, VOL. 32, L09601, doi:10.1029/2005GL022751, 2005

Westbrook, G., et al, Escape of methane gas from the seabed along the West Spitsbergen continental margin, GEOPHYSICAL RESEARCH LETTERS, VOL. 36, L15608, doi:10.1029/2009GL039191, 2009

234 Responses to “Arctic Methane on the Move?”

  1. 101
    Walt says:

    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

  2. 102
    prokaryote says:

    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.

  3. 103
    wili says:

    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.

  4. 104
    Edward Greisch says:

    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.

  5. 105
    Gilles says:

    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.

  6. 106
    ccpo says:

    [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

  7. 107
    ccpo says:

    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?

  8. 108
    jcrabb says:

    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.”

  9. 109
    Oxford Kevin says:

    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]

  10. 110
    Andreas Bjurström says:

    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 ….

  11. 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]

  12. 112
    Chris Dudley says:

    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.

  13. 113
    epidemiologist says:

    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.

  14. 114
    Dennis Denuto says:

    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…

  15. 115
    Nick Gotts says:

    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!

  16. 116
    Gilles says:

    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 ?

  17. 117
    Completely Fed Up says:

    “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.

  18. 118
    David says:

    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.

  19. 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.

  20. 120
    Oxford Kevin says:

    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]

  21. 121
    Andreas Bjurström says:

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

  22. 122
    Completely Fed Up says:

    “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.

  23. 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

  24. 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

  25. 125
    Hank Roberts says:

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

  26. 126
    ccpo says:

    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

  27. 127
    ccpo says:

    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…

  28. 128
    CM says:

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

  29. 129
    Lynn Vincentnathan says:

    #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]

  30. 130
    Ric Merritt says:

    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.

  31. 131
    NoPreview NoName says:

    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?

  32. 132
    David says:

    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.

  33. 133
    prokaryote says:

    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.

  34. 134
    Gilles says:

    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]

  35. 135
    Andreas Bjurström says:

    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]

  36. 136
    Completely Fed Up says:

    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?

  37. 137
    EdT says:

    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]

  38. 138
    Geno Canto del Halcon says:

    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.

  39. 139
    Completely Fed Up says:

    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]

  40. 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]

  41. 141
    Josie says:

    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]

  42. 142
    Brian Dodge says:

    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

  43. 143
    Dennis Denuto says:

    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.

  44. 144
    igmuska says:

    Dont’ panic…nuclear winter will solve global warming

    [Response: Awesome!]

  45. 145
    Blair Dowden says:

    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]

  46. 146
    Brian Dodge says:

    “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.”

  47. 147
    Ron Taylor says:

    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.

  48. 148
    Jacob Mack says:

    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.

  49. 149
    Thomas says:

    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.

  50. 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.