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Pushing Back Against the Methane Tipping Point
Jamais Cascio, 9 Mar 10

A piece in the latest issue of Science shows that there's a considerable amount of methane (CH4) coming from the East Siberian Arctic Shelf, where it had been trapped under the permafrost. There's as much coming out from one small section of the Arctic ocean as from all the rest of the oceans combined. This is officially Not Good.

Here's why: methane is a powerful greenhouse gas, significantly more powerful than carbon dioxide. There are billions of tons of methane trapped under the permafrost, and if that methane starts leaking quickly, it would have a strong feedback effect -- warming the atmosphere and oceans, causing more methane to leak, and on and on. The melting of methane ice (aka "methane hydrates" and "methane clathrates") is probably the most significant global warming tipping point event out there. If we see runaway methane from underneath the Siberian permafrost, we could see temperatures increasing far faster than even the most pessimistic CO2-driven scenarios -- perhaps as much as 8-10° C, very much into the global catastrophe realm. To put it in context: rapid methane releases have been implicated in extinction events in Earth's geologic past.

(Here's one piece of mitigating information: it's unclear how long this methane leak has been happening, or the degree to which the measured methane levels exceeds previous amounts. If we're lucky, this is actually a status quo situation, and we still have time before we reach a tipping point. But basing our strategy on "if we're lucky" is not very wise.)

Because of this tipping point/feedback process, a runaway methane melt won't stop on its own. When I've written before about desperation as a driver for the rapid (and risky) implementation of geoengineering, this is precisely the scenario I had in mind. If this news holds up, and if it can be shown that the methane leak is actually increasing, then I believe that we are certain to engage in geoengineering, and probably will do so before we have enough good models and studies to suss out any unwanted consequences. We'd be faced with a choice between guaranteed catastrophe or terrible uncertainty.

We'd probably try every geoengineering option available in the event of a methane runaway, but the one that most people would focus on would be the temperature management strategies: stratospheric sulfate injection, seawater cloud brightening, and (unlikely to happen but certain to get a lot of media attention) orbiting reflectors. But there's one more method we should consider. Understanding its potential requires a bit of science talk.

I noted earlier that methane is a "significantly more powerful" greenhouse gas than carbon dioxide. More specifically, it's at least 21 times more powerful a greenhouse gas than CO2; some reports (such as the first piece I linked to above) cite it as 30x stronger, and I've been seen as much as 72x stronger. The difference comes from how the effect is measured over time -- methane and carbon dioxide leave the atmosphere at very different speeds. Although CO2 takes upwards of a century to cycle out naturally, methane takes only about ten years. Why the difference? Chemical processes in the atmosphere break down CH4 (in combination with oxygen) into CO2+H2O -- carbon dioxide and water. In addition, certain bacteria -- known as methanotrophs -- actually consume methane, with the same chemical results. These processes have their limits, however; an abundance of methane in the atmosphere can overwhelm the oxidation chemistry, making the methane stick around for longer than the typical 8-10 years, and the commonplace methanotrophic bacteria evolved in an environment where methane emerges gradually.

These are pretty much the only two natural methane "sinks." There are a few small-scale human processes that can make use of methane (for the production of methanol for fuel, for example) and function as artificial sinks, but such efforts would be hard-pressed to capture methane released across two million square kilometers. So here's where we start to think big.

Both of the natural processes are, in principle, amenable to human intervention. The oxidation of methane into CO2 and water is a well-understood phenomenon, and relies on the presence of OH (hydroxyl radical); upwards of 90% of lower atmosphere methane is oxidized through this process (PDF). But OH is something of a problem chemical, in that it's also a key oxidation agent for many atmospheric pollutants, such as carbon monoxide and NOx. Although we could produce OH to enhance the natural chemical oxidation process, the side-effects of pumping enough OH into the atmosphere to oxidize all of that methane would be unpredictable, but almost certainly quite bad.

So what about methanotrophic bacteria? Such bacteria have long been recognized in freshwater areas and soil, and have had limited use in bioremediation efforts. Methanotrophic Archaea -- similar to bacteria, but a wholly different kingdom of organism -- were recently identified in the oceans; research suggests that methanotrophic Archaea may be responsible for the oxidation of up to 80% of the methane in the oceans. Methanotrophic microbes can also be temperature extremophiles, as they were among the various species found after the Larsen B ice shelf collapsed.

We recently began to learn much more about how methanotrophic bacteria function, as a team from the Institute for Genomic Research sequenced the genome of the methanotroph Methylococcus capsulatus. The scientists discovered that Methylococcus has the genomic capacity to adapt to a far wider set of environments than it is currently found in. They also looked at the possibility of enhancing the microbe's ability to oxidize methane, although admittedly for purposes other than straight methane consumption.

So here's the proposal: we need to deploy methanotrophic microbes at the East Siberian Ice Shelf. Methanotrophic Archaea appears to be best-suited for this task, but we don't know as much about them as we do about bacteria. If we need to modify the microbes (to consume methane more quickly, for example), we may need to work on Methylococcus bacteria, making them viable in extremely cold seawater. I suspect that working with the Archaea will probably be sufficient, but it's important to think ahead about different pathways. Either way, we should consider just how we could make use of methanotrophs to avoid a methane-melt disaster. Given the size of the region, we'll need lots of them, but that's one advantage of biology over straight chemistry: the methanotrophs would be reproducing themselves.

We need to be aware of possible unintended consequences, but at this point, it's not clear how additional methanotrophs would pose a larger risk; moreover, a mass of methanotrophic organisms would undoubtedly be helpful for reducing overall atmospheric methane beyond the Siberian release. Nonetheless, there are some crucial questions we need to answer before we could consider deploying natural or GMO methanotrophs:

  • Is it physically possible? Could a sufficient number of methane-eating bacteria even be produced to counter a fast release of methane from the Siberian ice shelf?
  • Is it biologically possible? Would methanotrophic Archaea survive in the Siberian ocean? Could a species of methanotrophic bacteria be engineered to be able to do so (as well as consume large quantities of methane)?
  • What are the unrecognized risks? What are we missing in an initial risk analysis? Saying "we don't know the risks" doesn't, in and of itself, mean "we should not attempt this," it means "we need to do more research." Clearly, if the risks from enhancing the methane consumption and environmental adaptation capacities of a methanotroph could lead (through species-hopping genes or simple mutation) to even harder-to-manage problems than gigatons of atmospheric methane, this isn't an option. Boosting OH levels in the region would be the fallback position, as we have more experience with managing CO and NOx pollutants.

    If the frozen methane in the Siberian ocean is melting faster, our options are extremely limited. We'd no longer be in a position to stop the melting, even by ceasing all greenhouse gas production today; the temperature increases we're seeing now are the results of greenhouse gases put into the atmosphere decades ago. And when methane melts, it appears to do so quickly -- there are signs that past methane clathrate events took less than a human lifetime.

    This is why I think that methane melt would inevitably mean geoengineering. But if this is the case, the pathway I suggest here may be the best option. The engineering options are enhancements of common natural processes, as opposed to something that emulates extreme conditions (such as sulfate injection). At least with current understanding, there would be few downsides to a greater-than-expected growth of the methanotroph population -- it might even be helpful in mitigating atmospheric methane coming from other sources, such as cattle.

    A further advantage is that this is a process that could begin after we start to see significant methane output and could still have a measurably positive result. Using microbes for bio-"scrubbing" of methane from the atmosphere would work on methane that was a decade old as readily as methane fresh from the permafrost. We'd still see some effect from the methane that makes it to the atmosphere, but eventual removal would help to reduce that effect. This means that we still have time to get more certainty about the methane situation before we would need to use the methanotroph option; we don't necessarily have to rush past our better judgment in response. With a process of this magnitude, it's worth taking the time to get it right.

    If we are seeing the beginning of a runaway methane melt, we would be facing a problem of a scale with few precedents in human history. No society on the planet would be unaffected; if left unmitigated, it would continue to affect the lives of our children, and our children's children, and generations beyond that. And remember, this is a fast process -- simply pushing a bit harder to reduce carbon emissions will do nothing to stop it.

    Our choices are few, and the risk of not acting is (potentially) immense. We may well be on the brink of a new era in planetary management. Let's hope we're up to the challenge.

    (Some of this essay reproduces text from my initial methanotroph proposal on Worldchanging back in 2005. At that point, it was speculation -- now, it's something we need to seriously consider.)

    This piece originally appeared on Open the Future

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    The melting of methane sinks is a significant Uh-oh! moment to put it mildly. The dangers off setting of a geo-engineering reaction from the powers-that-be with cascading unintended consequences are very real. Your proposal, understandably coming from a genuine interest to ameliorate this situation unfortunately falls into the two traps that wait to befall any intervention after-the-fact. I say this realizing that today is in all probability already within that time frame, long after any preventive measures can be assumed to be of use.

    Any scenario involving geo-engineering has two fatal preconceptions. First that this action will somehow allow the status-quo to continue, albeit in some slightly more virtuously modified form – the sobered heroes marching off into the future better and more thoughtful for the trials they've been through. And secondly, that our current position as masters of a seemingly unlimited energy supply will continue long enough, not only to tackle this additional Herculean job of "managing" the Earth's basic regulatory functions – while also magically converting the same energy economy that led to this catastrophe in the first place – but to also seamlessly morph into something both benign and at a scale that will allow point one and two to continue to be true for any appreciable time-frame.

    I make these points not to add to any sense of panic, nor to scourge anyone into a sense of guilt. It's long past-due that we learn ways to handle taking aboard a multitude of earth-shattering realizations without self-destructing emotionally and heading off from one set of unworkable fantasies to another. This isn't a call for "more research" instead of action either, although research is certainly always helpful. It's not a call to inaction or paralysis.

    Simply put, we need to find a way to handle these "bad days." This will require a level of adaptation to realities we've long ignored while we look for workable, effective methods of amelioration for the breathtakingly few, and probably extremely limited, interventions that remain with some chance of actually playing out.

    It's like the notion of "driving into the crash" as opposed to hysterically throwing our hands up screaming, or expecting to have a "time out" while we come up with some elaborate way to magically remove us from the reality of our disastrous predicament.

    Any realization of these depths to which our situation has brought us would be true signs of hope for some kind of future, however short, that might redeem the colossal disasters we've unleashed by showing that at long last we have some sense of proportion and of the limits of our will.

    Again, this is not a call for giving up, or looking for some outside intervention on our behalf, or of "atoning for past sins." This is a call for an engaged realism, that I'm afraid is still in exceedingly short supply.

    Posted by: Antonio Dias on 9 Mar 10

    Real Climate don't think that the current level of methane release is much of a problem (not that I think that that is cause for complacency!).

    Arctic methane on the move

    Posted by: Nick Palmer on 10 Mar 10

    Nick, thanks for that link. I'd be interested in hearing the author's thoughts in response.

    Posted by: Josh on 17 Mar 10

    Current levels aren't the problem; I'm focusing here on what happens with continued increases in methane, particularly if the Siberian emissions are rising (rather than remaining steady).

    Posted by: Jamais Cascio on 19 Mar 10

    The only risk of "seeding" methanotrophic microorganisms in Siberia is that the native microorganisms would outcompete then in the environment, and the seeded organisms wouldn't survive.

    There is a dictum in microbiology: Everything is everywhere, the environment selects. Psychrophilic methanogens (cold temperature-resilient) probably already exist in this environment if methane is in abundance. The genetic engineering question is whether there is anything we can do to speed the rate of methane uptake.

    Posted by: Chad on 2 Apr 10

    I wrote about some yet-unpublished (but still effectively peer-reviewed) research on this subject for Scientific American:

    Defusing the Methane Greenhouse Time Bomb
    Could methane-digesting bacteria and an Arctic cap of fresh water prevent a climate catastrophe?

    If this computer model is correct, even a large amount of methane release from the Arctic is likely to acidify the oceans rather than enter the atmosphere and heat up the planet. This could explain why, during the PETM, there were large extinctions of marine genera but on land, despite the warming and the large shift in where things were living, there was not a comparable wipeout of terrestrial species -- though the scientists I interviewed refused to speculate on that count.

    The take-home from this article is that there are physical processes that might prevent a deadly methane feedback, but that the methanotrophs can easily be overwhelmed by large quantities of methane in the water column, and that it's likely that their ability to process methane is limited by the availability of other nutrients, possibly including iron.

    In fact if you read all the way through to the end, you'll see that the lead author proposes a geoengineering scheme with the same goal as yours, but via a substantially different mechanism (namely, the so far justifiably maligned use of ocean fertilization).

    Posted by: Christopher Mims on 11 Apr 10

    Ok Guys, I honestly think you are over motivated in your race to save the planet. One thing is to reduce or stop the incredible amounts of CO2 blown into the air by man-made activities. The discussion here is about trying to stop a natural phenomenom in order to save the planet. What is next? Trying to stop a volcano from erupting? Stopping continental plates from drifting, because we know that all the ice in antarctica will melt in several million years.
    We are not killing the planet, we are killing ourselves along with the majority of animals and plants as they exist Today. Give it a million years and all will be back in equilibrium. Maybe different species, but a healthy planet with chances for new live, maybe even intelligent life.
    In the meantime we have to learn from our past mistakes such as burning fosilfuels etc. Do it better and cleaner in the future and simply hope that we are not past the point of no return. But stopping natural occuring events, even if we caused them, is over-motivated. Thanks for reading. Comments appreciated.

    Posted by: Thomas on 13 Apr 10

    Rather interesting blog you've got here. Thank you for it. I like such themes and everything connected to this matter. I definitely want to read more soon.

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    Posted by: Kate Smith on 7 Sep 10

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