Playing Games With Global Fire — Putting Scientific Arguments over Arctic Methane Emissions into Context

A pool of hydrates destabilizes on the ocean floor.

A pool of hydrates destabilizes on the ocean floor.

UPDATED ON AUGUST 3 DUE TO NEW INFORMATION
This week, the scientific journal Nature issued a bombshell article in which Peter Wadhams and a number of Arctic specialists warned that very large methane pulses, on the order of 1-50 gigatons in a single year, are likely to begin to appear soon in the Arctic. Other specialists, including Gavin Schmidt, a climate scientist at NASA’s GISS division, have noted that such an event is very unlikely.

Schmidt, in his argument, points toward past periods — 8,000 and 125,000 years ago — when the summer Arctic was mostly ice free and notes that there is no geological evidence of rapid release during these times. Wadhams, on the other hand, points toward large methane plumes that are already rising from a region of the East Siberian Arctic Shelf — a region vulnerable to rapid warming. Joining the mix is a NASA scientist, Ed Dlugokencky, who claimed in a recent Live Science article, that there has been no detectable change in Arctic methane emissions over the past two decades.

Critics of Wadhams have also made an interesting claim that, for the methane to have a ‘significant impact’ most of it would need to release rapidly. David Archer, a climate scientist at the University of Chicago noted in the Live Science interview:

“It [methane] has to be released within a few years to have much impact on climate, but the mechanisms for release operate on time scales of centuries and longer.”

There’s no indication what Archer is referring to, the ESAS stores (composing about 500 gigatons) or the much larger Arctic tundra and hydrate stores, composing hundreds to thousands of gigatons or global methane stores which are about double that of the Arctic (I’ll respond to this more in my assessment below).

What these arguments present is a veritable scientific fur-ball. One that will be very difficult for the casual observer to unravel and one we had better damn well get right soon as the Arctic begins to enter a new ice-free state not seen in over 800,000 years.

My assessment

Bubbles of Methane Locked in Sea Ice

Bubbles of Methane Locked in Sea Ice. Image source: The Alaska Dispatch.

It’s basically accepted science that release from the vast Arctic methane stores will increase as the planet warms, and sea ice, ice sheets, and tundra continue to melt. The argument, right now, basically hinges over how fast this process will occur — years, decades, centuries or millennia. As to whether the amount of methane coming from the Arctic is increasing or not, I’d like to see the data Ed Dlugokencky is looking at. Because, to my knowledge there is no complete survey of annual Arctic methane emissions. If he would like to provide them, they would be very helpful. And if we don’t have means to provide such information, then I think it is urgent we develop it.

What is available, at least in open source data, shows that atmospheric methane levels in the Arctic are higher than the global average, which would indicate a local emission of large volume (melting tundra, peat bogs, ocean emissions, thawing ESAS stores, environmental fire releases etc). And numerous studies — CARVE, the ESAS study, and others — have found very large local emissions sources in the Arctic in the megaton range and at levels far higher than previously anticipated. Wadhams joins a group of experts who believe a more rapid emission is possible (on the order of 1-50 gigatons per year in the case of the ESAS). Schmidt seems to believe there is no possibility for a release on a scale of anything less than 1,000 years or more.

My own opinion is that there is no possible means by which the Arctic’s methane stores can remain locked in their various traps so long as human greenhouse gas emissions continue along a business as usual path. In my view, it is entirely likely, that along this path, nearly all these stores will have released within a 500-1000 year time-frame, with Arctic methane emissions beginning to steadily increase now. The human greenhouse gas forcing will be enough to render the Arctic Ocean ice free during summer within the next few decades at the longest. And, without a major interrupting melt pulse from Greenland, this ice free state will continue to advance until winters show no ice as well. The last time this happened was likely in the Pliocene, around 2.5 million years ago. But the Pliocene oceans were settling down into a glacial period and not emerging from one. Such a set of rather disturbing circumstances will almost certainly result in large methane releases from the Arctic that are significant and contribute markedly to warming — even if such events don’t happen as fast as Wadhams warns.

Yet the gap between the two estimates from professional scientists is wide and no-one (except, apparently, me) seems to be occupying any middle ground in this particular discussion. Schmidt uses past interglacials where sea ice mostly vanished during summer time as a flimsy reassurance. But Schmidt does not acknowledge that we are out of reckoning of these time periods due to the clear and obvious fact that the current CO2 levels of 400 ppm puts us in the context of the Pliocene, nearly 2.5 million years ago, when the Arctic Ocean likely saw no sea ice and, as mentioned above, the newly emerging Arctic Ocean is one charged with carbon stores. So the situation may well be worse than the Pliocene. Sadly, this imperfect corollary is a moving target because the human emission that is currently nearly 32 gigatons drives CO2 levels higher by 2-3 ppm each year. Such an emission is at least ten times faster than any comparable emission in geological history — even that seen from the massive Siberian flood basalts during the Permian. This rate of emission, unless rapidly halted, will hit the Earth System like a 10 kilometer boloid — only potentially locking in catastrophic conditions that last for tens of thousands of years, not decades.

Wadhams, in contrast to Schmidt uses the Shakhova study and his own observations to support a claim that rapid methane release on the order of 1-50 gigatons is likely over the next 30 years. It is worth noting that a study conducted by Carolyn Ruppel refuted Shakhova’s findings for rapid methane hydrate release. This refutation may or may not stand as disproof. It’s too early in the scientific process, at this point, to be certain. So, though I agree with Schmidt and Archer that a slower release is more likely, I’m not assured enough by a single refutation to agree with them in their complete dismissal of Wadhams concerns.

The assertion that a slower rate of methane release would have little effect is also incorrect. Global methane stores are on the order of thousands of gigatons. And there are many ways by which such stores could hit the atmosphere — action by bacteria on thawing tundra, direct warming of anoxic carbon stores in shallow sea beds, heat forcing directly to hydrate locations, and potential for slope collapse and large release during destabilization. Some of these mechanisms remain unproven in the science. But all remain on the table. Should just 500 megatons of this vast store release each year (less than 1/10000th the total amount), global methane emissions will have doubled, putting at risk sinks and creating a very strong additional forcing to add to CO2 emissions. Global methane levels are increasing at a rate of around 4 ppb each year, some of this increase comes from the approximately 350-400 megaton human release, the rest comes from an Earth Systems release totaling around 130 megatons of which the Arctic is a portion. Yet the sinks are limited and there is good reason to believe that they will be saturated soon if current methane emissions double or more.

As I’ve noted before, I think that methane release is a part of a total Earth Systems response to a given forcing, in this case, human warming. And that total, given our best views of paleoclimate, is somewhere between 4-7 degrees Celsius of warming for each doubling of CO2 once all the ‘slow feedbacks’ come in. A 50 gigaton release in a single year would be far outside this usual range — a truly catastrophic event. So, in this case, Schmidt is probably right. But, as during the Permian, we sit at the end of a rather long glacial period in which global carbon stocks represent a very large charge and, potential, though unproven, larger than expected climate response. This is a disturbing circumstance and, in addition to the still accepted in broader scientific literature, Shakhova study, provides a strong reason to not entirely dismiss Wadhams concerns. In addition to these risks and considerations, lower levels of still significant methane release are likely still a significant and non-dismissible part of the total Earth System response. Responses we may start to see now and of which we have point source, though not broader, evidence for at this time.

The controversy, therefore, is in no small part caused by a lack of clarity and context. It is also due to the transient and amplifying nature of our current climate crisis. This is not an attack on the science, but a direct call for more effort, study, and proofs — from both sides of the argument. We need more context, not broad claims and flat dismissals. Such effort, I believe, would make the science stronger and provide a better tool for human resilience. So this is also an appeal for more direct support from policy makers — for all those who investigate Earth Systems responses to climate change.

To this point, I’d like to add Charles Miller’s own statement regarding the NASA CARVE mission with which he is involved:

“Permafrost soils are warming even faster than Arctic air temperatures — as much as 2.7 to 4.5 degrees Fahrenheit (1.5 to 2.5 degrees Celsius) in just the past 30 years. As heat from Earth’s surface penetrates into permafrost, it threatens to mobilize these organic carbon reservoirs and release them into the atmosphere as carbon dioxide and methane, upsetting the Arctic’s carbon balance and greatly exacerbating global warming.”

To this last point made by a scientist outside of the current controversy, I continue to believe that a rapid reduction in greenhouse gas emissions is a necessary and urgent response. To Schmidt and others who would cite past interglacials, I would add that unless human carbon emissions stop soon, the only set of geological events that will be worth looking at for long-term corollaries are the PETM and the P-T, especially after the ice goes. And it will surely go unless said soon human emissions halting actually happens.

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21 Comments

  1. Steve

     /  July 31, 2013

    That is a really cool picture of the methane bubbles!

    Reply
  2. Reblogged this on Climate Force.

    Reply
  3. Arctic methane catastrophe scenario is based on new empirical observations
    Critics of new Nature paper on costs of Arctic warming ignore latest science on permafrost methane at everyone’s peril http://www.theguardian.com/environment/earth-insight/2013/jul/31/artic-methane-catastrophe-empirical-evidence

    I would rather see a discussion based on probability than credibility. And a discussion which includes all greenhouse gas sources, ie. methane hydrates from ocean seabed deposits, permafrost thaw, soil respiration, wildfire feedbacks in higher latitudes, pipeline leakage (which is increased through permafrost melt), thermokarst formation, carbon river discharge providing material for decomposition…

    DOC is a food supplement, supporting growth of microorganisms and plays an important role in the global carbon cycle through the microbial loop. Moreover it is an indicator of organic loadings in streams, as well as supporting terrestrial processing (e.g., within soil, forests, and wetlands) of organic matter. Dissolved organic carbon has a high proportion of biodegradable dissolved organic carbon (BDOC) in first order streams compared to higher order streams. [..] The BDOC fraction consists of organic molecules that heterotrophic bacteria can use as a source of energy and carbon. BDOC can contribute to undesirable biological regrowth within water distribution systems. http://en.wikipedia.org/wiki/Dissolved_organic_carbon

    They release energy by oxidizing carbon and hydrogen atoms present in carbohydrates, lipids, and proteins to carbon dioxide and water, respectively. Most opisthokonts and prokaryotes are heterotrophic. http://en.wikipedia.org/wiki/Heterotrophic

    Another important point is to acknowledge better the latitude characteristic of today’s cryospheric setup and i guess that this unique scenario is different from past deglaciation patterns, hence different feedback potential in time and space.

    Reply
    • You’re absolutely correct on all these points. It’s pretty clear from both sides of the discussion that we don’t have an accurate view of the problem. Setting unrealistic and unproven goal posts for prediction doesn’t help. Probabilities are certainly more worthwhile and we do need more accurate assessments and a much more realistic conversation.

      These specialists need to get out of their respective ivory towers and start working together to paint a picture, not competing with one another for scientific recognition.

      Yes, and the slow but almost certain killing of the oceans scenario under BAU with multiple deadly episodes for land dwellers, in the end, is a terrifying potential outcome. We are already starting the long and painful transition from a mixed ocean to an anoxic ocean. We’re probably a few Heinrich events away from that, but do we really want to continue on along that, very ugly, path? Since the human forcing is so large and fast and since so much in the way of carbon stores have built up over the millenia within the ice, we may be just decades away from setting up a situation where an angry transition to a Canfield type ocean, over centuries, is locked in. But, even before that, humans get hit by out of context damage to the stable climate systems we rely on for survival even as a major knock-out blow builds up for centuries.

      Thanks for the excellent comment and best wishes.

      Reply
  4. james cole

     /  July 31, 2013

    I have never seen any follow up information on the great methane plumes detected off of the coast of eastern Siberia a year or two back. The Russian academy of sciences released a report on the detection of mass growth in what had been small methane plumes. Russian science is biased towards downplaying global warming, being that Russia is a fossil fuel exporter. But in this methane case, even the Russian scientists involved expressed shock at the releases they detected coming from the warming seas up there.
    As an Off Topic side note: News from the Daily Mail today reports Spain bracing for a heat wave of up to 43C! And with record high night time temperatures expected as well.
    The Siberian heat wave of late has been reported by the DM as well, a more anti global warming news paper than the DM would be hard to find, but their headlines are becoming more and more about massive heatwaves and extreme weather events. The news is beginning to trump their political stance!

    Reply
  5. james cole

     /  July 31, 2013

    In the Arctic are we not seeing the first huge positive feedback loop in action. Melting ice replaced with open dark waters. You go from almost zero heat absorbing white, to large heat absorbing dark blue.
    Since science was dead wrong as to how fast arctic sea ice would disappear in summer, are not many of them bound to be dead wrong on the speed and size of methane releases from land and sea up there?
    Two things scare me. The Methane plumes I mentioned above from Siberia’s arctic seas. And the present methane spike associated with the Siberian heat wave and wild fires.
    Taken together, these two ought to be a sharp slap in the face to anyone downplaying the methane threat on the high north.

    Reply
    • Well, I think Wadhams is probably a little bit ahead of the likely curve on both sea ice and methane, but not by too much. The rest of science is still a bit too conservative on these issues for my taste. And you’re right, the IPCC consensus models on sea ice melt were dead wrong.

      Reply
  6. Steve

     /  July 31, 2013

    I work for some regional insurance carriers that are as republican entrenched as you can get and they are finally swallowing the pill that we aren’t in some short trend of violent weather. That’s about as much as they will acknowledge. LOL! It’s a start though and a silent admission to the problem. I had someone two years ago get up and leave the table because they were so mad that I told them the sand that they were sticking their heads in would be getting warm soon.

    Reply
  7. climatehawk1

     /  July 31, 2013

    Climate scientist contact on Twitter says of this post FYI: “it doesn’t get Archer’s point. Also, while no good paleo analogs for whole climate, Eemian is ok for Arctic CH4. False alarm.” Oops, and adds, “Lots of concern around re the Nature comment. Watch for the Skeptical Science article on the science coming soon.” (Real-time update. :))

    Reply
    • Sorry, there’s a pretty clear disagreement on this issue and there’s many reasons to doubt why the Eemian is a ‘good analogue’ for anything regarding current climate.

      Will look for the Skeptical Science article. But it will have to explain clearly why rising methane release is not a concern when the Arctic sea ice is melting and Arctic tundra is thawing.

      Anonymous climate scientist also fails to address the point that even slower methane emissions than those identified by Wadhams are cause for concern. At the very least, paleoclimate shows Earth Systems Sensitivity at double ECS and methane and albedo change likely play a large part in this.

      Best.

      Reply
      • climatehawk1

         /  August 2, 2013

        The Skeptical Science post referred to is now up: http://www.skepticalscience.com/toward-improved-discussions-methane.html . Regarding the “anonymous climate scientist,” that was my decision, not his–I didn’t feel I should use his name without permission.

        Reply
        • Fair enough. I can completely understand such a decision. Will look forward to reading the Skeptical Science article tonight. Will probably post a response here.

        • I’ve read the Skeptical Science article and will need to mull it over for a while before developing a full response. However, I do believe that Skeptical Science has come clearly down on the side of one group of scientists represented by Archer and Schmidt and in opposition to another group of, admittedly more alarmist, scientists represented by Wadhams and Shakhova etc.

          Archer and Schmidt via Skeptical Science do bring up interesting points. And I agree that Wadhams needs more proof to determine level of risk regarding 1 gt + annual releases.

          But I think that Archer needs to either qualify or back away from his earlier states of lower releases ‘not being significant.’

          As for methane’s implication in PETM, I’m going to have to do more research and look back at notes. But it appears to me that Hansen is also on the side of those implicating methane in the PETM. It will take some time to do the heavy lifting in this respect…

          Generally, I think that using peak Eemian and 9,000 year ago forcing levels for corollaries to 21rst century potentials are not good analogues. The 400 ppm CO2 forcing is greater than those two periods and this, as I noted before, is a moving target. As I’ve said before, the Pliocene, in my view is a better place to start (if looking at the next 10-30 years) but, at that time, you wouldn’t have had the same deposition of Arctic carbon stores as you are entering glaciation rather than emerging from glaciation.

          I can’t help but think there should be some degree of scientific middle ground between Archer and Schmidt and Wadhams. In this respect, the Skeptical Science article, I think leans far too heavily on the slow release side, so as to sound almost like ‘no release.’

          To this point, I think more clearly defining boundaries is appropriate.

        • climatehawk1

           /  August 2, 2013

          Thanks. Once you have given it some thought, I hope you will consider a comment at Skeptical Science. I think that would be worthwhile. There are often lengthy discussions and debates in the comments there.

        • Cheers Climate Hawk,

          I just posted my thoughts to Skeptical Science. I think I’ve been pretty thorough and am not in the least bit certain I want to get into a giant, drag out, discussion there. That said, I hope the comment inspires productive responses.

          If you’re in any way associated with John Cook, please let him know that, despite my disagreement with him on this issue, I hold him in the highest regards and hope he will consider a broader view on methane release in the future. Those of us who are concerned about methane release and who hope for an appropriate policy response, especially when it comes to mitigation, I feel, are the very opposite of climate change deniers. So I am somewhat stung to have seen that what I consider to be an appropriate, if somewhat overstated warning to be labeled as such.

          Warmest regards.

  8. Hey Robert, mind checking my simple math here? If we saw 2 gigatons of methane release per year (a middleground estimate by this study’s standards: 30 gigatons total over 15 years), at 72x CO2 that’s at least an annual addition of climate forcing four times our current expected emissions of ~35 gigatons CO2/year, right? likely higher, if the methane is released by sudden pulse instead of steady drip and the GWP averaged over 5 years instead of 20 is still greater?

    Truly a stunning & grave prediction. If it turns out to be even half correct… God help us all – – –

    Reply
    • We should be concerned about any additional methane release, at this point. But a release exceeding even 1 GT per year should terrify us. This high level of release is less likely, but I’m not convinced the science is so settled that we should dismiss the risk as too remote.

      Your math is roughly correct, although the OH sink would suck up a greater portion of the methane at first due to added contact, so the total forcing, at first, would probably not be quite so high, perhaps 2.5 to 3.5 times CO2 forcing (when factoring in sink response, lowering heat capture efficiency due to higher concentrations etc) over the duration of the event + about 3-5 decades, which is still ridiculous.

      The problem is that the OH sink is limited and we don’t know its total depth. At some point, that will fill and then you’re really in for hell as methane’s lifetime in the atmosphere, at that point, will double or more.

      This is a nasty problem and not one with an N of 1 as Schmidt seems to think. Living in the abstract world of the Eemian at 400 ppm CO2 and 1800+ ppb CH4 is not a good corollary to what we’re experiencing now. And the long periods of glaciation have served to provide a large charge of those carbon stocks that are particularly susceptible to releasing methane. The Eemian, in such a context, has very low probability (N of about 1), of being a rational corollary.

      God help us is a good response if we don’t drastically cut CO2 emissions. We would do best to help ourselves while we still have means.

      Reply
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