« PIOMAS November 2013 | Main | In memoriam: Albert A. Bartlett »

Comments

Feed You can follow this conversation by subscribing to the comment feed for this post.

wili

Thanks for covering this important story, neven.

As far as I can tell this is a feedback in at least three ways:
1) Storms are pretty certain to increase, and to become increasingly intense as the climate warms;
2) There will be more and more open water for longer and longer that will provide more opportunity for those storms to create larger and larger waves;
3) The waters coming out of Siberia's rivers will become warmer and warmer, increasing warmth of sea bottom further destabilizing permafrost and methane.

Each of these will increase the amount of methane escaping from the ocean bottom going forward. And of course the methane will increase each of these, as it is a powerful GHG.

Feedbacks tend to turn what would be linear rates of growth into exponential rates of growth. What we don't know yet is what the rate of growth of these emissions (nor if there will be sudden massive releases).

Colorado Bob

This clip popped-up today from a German team working onshore permafrost on the Lena delta , well worth watching :

Disappearing Permafrost

http://www.dw.de/disappearing-permafrost/a-17250005

wili

"Sudden Shutoff of Carbon Emissions Would Not Stop Global Warming, Study Says"

" ...even if global carbon dioxide emissions came to a sudden halt, the residual CO2 in the atmosphere would continue to contribute to global warming for centuries.

… Frolicher’s study, published in the journal Nature Climate Change, suggests that the 2 °C rise may be achieved with a lot less CO2 in the atmosphere.”If our results are correct, the total carbon emissions required to stay below 2 degrees of warming would have to be three-quarters of previous estimates, only 750 billion tons instead of 1,000 billion tons of carbon,” Frolicher said.

The reason for this disparity in figures is that previous models did not take into account the gradual reduction in the ocean’s ability to absorb heat from the atmosphere, particularly at the poles."

http://www.natureworldnews.com/articles/5063/20131125/sudden-shutoff-carbon-emissions-stop-global-warming-study.htm]http://www.natureworldnews.com/articles/5063/20131125/sudden-shutoff-carbon-emissions-stop-global-warming-study.htm">http://www.natureworldnews.com/articles/5063/20131125/sudden-shutoff-carbon-emissions-stop-global-warming-study.htm">http://www.natureworldnews.com/articles/5063/20131125/sudden-shutoff-carbon-emissions-stop-global-warming-study.htm]http://www.natureworldnews.com/articles/5063/20131125/sudden-shutoff-carbon-emissions-stop-global-warming-study.htm

http://www.princeton.edu/main/news/archive/S38/51/51I69/index.xml?section=topstories]http://www.princeton.edu/main/news/archive/S38/51/51I69/index.xml?section=topstories">http://www.princeton.edu/main/news/archive/S38/51/51I69/index.xml?section=topstories">http://www.princeton.edu/main/news/archive/S38/51/51I69/index.xml?section=topstories]http://www.princeton.edu/main/news/archive/S38/51/51I69/index.xml?section=topstories

(Thanks to hank at RC for these links.)

Colorado Bob

3:30 into this clip Julia Bolike reports they are measuring to a depth of 27 meters, and report a 1C degree rise since 2006. She reports that Alaska is finding similar numbers. I have seen other numbers from the Hudson Bay's lowlands ( 15 meters deep ) reporting the same big moves.

All the missing heat is thawing ice 50 feet in the ground , but once that's done. Those swamps in the Lena delta will be 50 feet deep in summer. Not the old 3 feet.

Colorado Bob

East Siberian Arctic Shelf experts Natalia Shakhova and Igor Semiletov.

11 Russia sailors died trying to help them during this study :

" In August 2010, 11 sailors aboard a tug boat drowned in the Laptev Sea while trying to rescue a fishing boat in the Arctic waters north of Siberia. What didn't emerge at the time was that they were attempting to rescue a team of Russian researchers probing whether storms that stir up the ocean will increase the release of methane from the sea bed as the Arctic warms."
http://www.newscientist.com/article/dn24639-arctic-storms-speed-up-release-of-methane-plumes.html#.UpQARiTnbIV

John Christensen

@wili,

From the Frolicher article you included:

… Frolicher’s study, published in the journal Nature Climate Change, suggests that the 2 °C rise may be achieved with a lot less CO2 in the atmosphere.”If our results are correct, the total carbon emissions required to stay below 2 degrees of warming would have to be three-quarters of previous estimates, only 750 billion tons instead of 1,000 billion tons of carbon,” Frolicher said.


"Only 750 billion tons":

750 billion tons is a lot of carbon, and will take time to release into the athmosphere.

From burning fossil fuel and deforestation, we release about 7 billion tons of carbon each year.

Of the 7 billion tons, various CO2 sinks take up about 3.6 billion tons, so 3.4 billion tons is added to the athmosphere.

It will therefore take us 220 years of current contribution rate to add 750 billion tons of carbon to the athmosphere.

While some CO2 sinks become less effective eventually, other CO2 sinks such as weathering become more effective with higher rates of CO2 in the athmosphere and higher temperatures (http://www.karst.edu.cn/introduction/enGeo2000.pdf).

Are my numbers wrong, or is he stating that with current release rate, we will be below 2 degrees of warming after 220 years?

Werther

This is from CO2now.org:
Dr. Mike Raupach of CSIRO: "A continuation of the emissions growth trends observed since 2000 would place the world on a path to reach 2 degrees Celsius above pre-industrial times in 30 years"
so you might be a bit optimistic here, John.

John Christensen

@Werther,

I may be, but am just trying to get the numbers to match.

From CO2now.org:

Data for Global Carbon Emissions
(Fossil fuels, cement, land-use change)

Year Carbon Emissions
2012 9.7 billion metric tonnes per year
2011 9.47 billion metric tonnes per year
2010 9.19 billion metric tonnes per year
2009 8.74 billion metric tonnes per year
2008 8.77 billion metric tonnes per year
2007 8.57 billion metric tonnes per year
2006 8.37 billion metric tonnes per year

With CO2 sinks taking away about 50% of the carbon, the build-up is about 5 billion metric tonnes per year with current rate.

With 750 billion metric tonnes that takes 150 years..

I do not know the total human-caused build-up until today, but it seems it would need to be at least 600 billion metric tonnes, if just 150 billion metric tonnes need to be added still.

Is CO2now.org stating that the total today is 37 billion metric tonnes? (http://co2now.org/Current-CO2/CO2-Now/global-carbon-emissions.html)

I am not trying to be optimistic, just trying to make the numbers work.

John Christensen

From CO2now.org the total added carbon to the athmosphere since 1960 is about 166 billion metric tons.

John Christensen

Is there a chance that Frolicher and Dr. Mike Raupach are talking about different things, or have different starting points?

Or perhaps, one of them might be a bit pessimistic here.

Bob Henson

According to IPCC, we'd emitted roughly 515 gigatonnes (metric gigatons) of carbon by 2011. See section E.8, second bullet, page 25, of the WG1 SPM:
http://www.climatechange2013.org/images/uploads/WGI_AR5_SPM_brochure.pdf

I think Frolicher was including this in his proposed new upper limit--i.e., we only have about 235 gigatonnes left to emit, rather than 485 gigatons. If we're adding roughly 9-10 gigatonnes per year, this implies we might break through the threshold in less than 30 years.

Bob Henson

PS: Note that the Princeton news release and the IPCC SPM are both referring to emissions rather than accumulations, so they're taking into account that only a portion (roughly half) of the carbon from the CO2 emissions will stay in the atmosphere.

John Christensen

@Bob,

Thanks, that certainly helps. CO2now.org has accumulated emissions 1960-2009 at around 342 gigatonnes, but not too far off I guess with regards to emissions from early industrialization until 1960 to be added.

The 235 gigatonnes left to emit is very realistic, no doubt in my mind that this will happen..

Dan Ellis-Jones

Hi John,

The difference is that there is a confusion over the metric.

You are right in saying that there was 9.7 (give or take) gigatonnes of carbon (C) released into the atmosphere. However, to turn that into a measure of CO2, you need to multiply the amount of carbon (C) by 3.664, as 1kgC = 3.664kg of carbon dioxide (CO2).

So 9.7GtC equates to about 35.5GtCO2.

And of course that doesn't take into account the other GHGs.

Which brings me to a question - can someone tell me where to get a reliable measure of CO2-e? This metric seems to have disappeared recently. Is it not a robust measure anymore, or is it just too scary to talk about!? :)

Eli Rabett

Color Eli skeptical. Not that there are emissions from the ice shelf, but rather that they are not of the magnitude that Shakhova claims. Looking at the SCIACHAMY column density it appears that the major emission in Russian Eurasia is from the middle of Siberia north China and the SE Asia rice paddies

http://rabett.blogspot.com/2013/11/eli-and-weasel.html

John Christensen

@Dan Ellis-Jones,

CO2now.org appears to use "CO2 emission" and "carbon emission" interchangeably - and in error: http://co2now.org/Current-CO2/CO2-Now/global-carbon-emissions.html

Given that change in land use was a bigger part of CO2 emissions before 1960 I do not see necessarily a conflict between the CO2now.org total and that of IPCC, and as mentioned above the emission of another 235 gt of carbon (860gt of CO2) in the next 30 years is quite attainable, if not reached in 20-25 years..

John Christensen

What I got confused about was the difference between emission and what is added to the atmosphere. I thought the 750gt of carbon number was the required level of carbon being added to the atmosphere, which is not correct.

John Christensen

@Dan,

The EPA has a folder on GWP (global warming potential): http://www.epa.gov/cpd/pdf/brochure.pdf

From this you see that methane is 21-23 times as potent as CO2 (from IPCC second and third assessment, but should still be valid).

Fwmbrown

Anyone looking forward to the forthcoming Arctic Fracking bonanza and consequences thereof?
CMIIW. but aren't there also clthrates sub-surface in the Gulf of Mexico?

crandles

Quote:
"noted how a lot of models predict that a combination of Arctic sea ice and land masses that become snow-free earlier and earlier in spring, could lead to more cyclonic activity in the Arctic. As we saw this melting season, it could be a negative feedback preserving more sea ice but we learn now that .... Every advantage has its disadvantage, it seems."

I don't think this is right. Snow cover this April was, given the trend, unusually high and little sea ice was melted whereas previous years had low ice in April and high sea ice melting. (It is less clear if you look at May or June.)

I don't think you can suggest a feedback from 1 years data. I think it is pretty logically safe and previously established that it is a positive feedback not a negative one.

So it is bad in both ways though I don't think either is particularly surprising.

Neven

You're right. I should've worded that better as I didn't mean to imply that what we saw happen this year was a negative feedback due to low NH snow extent.

Hans Gunnstaddar

The idea of a carbon allowance that will allow continued CO2 emissions for X number of years before 2C is exceeded, seems disingenuous due to world temps during previous periods of 400 ppm CO2 exceeding current temps.

There is momentum from already released emissions that is in the process of increasing ocean temps, and until that momentum ceases in 30-40 years we won't know the full extent of those temperature increases. We may in fact have already juiced the system enough to exceed 2C.

Hans Gunnstaddar

By ceasing in 30-40 years, I mean of course in the hypothetical case of stopping all CO2 emissions now, which of course won't happen. Which means the momentum will only continue to build.

Also, what about feedbacks increasing C4 emissions? The idea of a CO2 allowance in my view is ludicrous. If we are going to continue to emit CO2 we need to find ways to sequester it directly from the atmosphere and in extremely large quantities, because both China and India are planning quite a number of new coal powered plants.

In spite of increasing use of renewables, CO2 emissions continue to increase YOY.

wili

On the global warming potential of methane, Shindell et alia wrote an article a few years ago in which they estimated the GWP of methane to be 35 times that of CO2 in century time scales, 105 times in decadal time scales.

IIRC, they got that number by considering that in the real world most of the CO2 being emitted by industry also was emitting significant quantities of GW masking aerosols, and the cooling effect of these needed to be figured into the calculation (though there may have been other considerations).

There have been recent studies that suggest that the cooling effect of aerosols is not quite as great as was once thought, so perhaps those figures need re-adjustment.

Hans, I share your views in this case.

wili

Eli, thank to the link to your always-fun-to-read blog. Please do note that some of the commenters there have posed some pretty impressive counter claims, not the least being Tenney Naumer's point:

"For example, a paper from U Bremen which discusses the SCIAMACHY ENVISAT results includes a caution for measurements taken over water."

GeoffBeacon

I'm getting dozier. I have just used Google's site search to find if there had been any mention on this blog of the Last Hours video about the Great Dyings caused by the dissociation of methane hydrates.
http://www.youtube.com/watch?v=sRGVTK-AAvw

It seems someone called GeoffBeacon mentioned it but there was no response.

It's scary. But is it valid?

Wayne Kernochan

@neven: as noted in my blog waynekernochanblog.blogspot.com, Hansen in his recent draft paper attempted to estimate the contribution to global warming from methane and a couple of other GHGs aside from carbon dioxide, and based on past episodes he came up with an estimate of 75% CO2, 25% other (I would assume methane is the major component of "other"). So if we say methane will contribute about 0.6 degrees C to the heating already in the pipeline (total 2.3 degrees C), of which 3/4 should affect things in the short run (a few decades) - and another 0.3 degrees by 2100, then we would have Hansen's projected methane effect overall. Plus, the effect in the Arctic is 5/3 that, or 1.5 degrees C overall.

Susan Anderson

fwmbrown, yes, I had been wondering, there were certainly clathrates involved in the one of the Macondo (Deepwater Horizon) blowup failed spill plugs. I had to look it up:

http://en.wikipedia.org/wiki/Methane_clathrate

At sufficient depths, methane complexes directly with water to form methane hydrates, as was observed during the Deepwater Horizon oil spill in 2010. BP engineers developed and deployed a subsea oil recovery system over oil spilling from a deepwater oil well 5,000 feet (1,500 m) below sea level to capture escaping oil. This involved placing a 125-tonne (276,000 lb) dome over the largest of the well leaks and piping it to a storage vessel on the surface. This option had the potential to collect some 85% of the leaking oil but was previously untested at such depths. BP deployed the system on May 7–8, but it failed due to buildup of methane clathrate inside the dome; with its low density of approximately 0.9 g/cm3 the methane hydrates accumulated in the dome, adding buoyancy and obstructing flow.

As far as I've been able to understand, one of the arguments against the likelihood of this "burp" idea is that as the clathrates are not at the surface, they are neutralized as they rise to the surface. If I were you I'd look at the graphical evidence Tenney presented over at Rabett's. None of us know, but it appears there's a bit more to the story than mere charlatanism. She shared this with me when she was developing it some time ago and you may be better able to make sense of the graphic evidence than I could.

RealClimate did a lot of work on methane, and while conservative and careful, I tend to trust them on most issues of science.

http://www.realclimate.org/index.php/archives/2012/01/much-ado-about-methane/

As is often the case, you better-informed science people show me extraordinary patience, as in this inline comment from Gavin:

http://www.realclimate.org/index.php/archives/2013/08/unforced-variations-august-2013/comment-page-2/#comment-402648

I think there's more to the story, but the unforced variations would not be so easy to find if I didn't remember my blushes!

Ggelsrinc

One of the problems I've noticed is the perception of scale and longevity. I've seen numbers all over the board about the greenhouse effect of methane. Is it 20 or 100 times more times than CO2 and why compare ppb to ppm as if they are equal and not a thousand times different?

The thing that will eventually melt the ice sheets and flood our coastal cities is CO2. Methane is a problem, because it will live in the atmosphere for a long time, but I don't see evidence of past methane problems during periods warmer than today.

Large facilities like nuke and coal plants need plenty of water to cool themselves during off peak times, so take a look at them during the morning or at night.

Water will not stay in the atmosphere very long and CO2 and methane will. My point is they are all emissions and I don't want any of them, but I can accept the water, because it won't be around for a long period of time and it's useful as rain.

Fwmbrown

ggelsrink; 23 times more potent, but atmospheric lifespan only 8-11 years, compared to much much longer for CO2. So you're right.
Wally Broecker speculated that the Laurentide event might have been connected to a mega-huge clathrate release from a Norwegian shelf collapse, but has since expressed doubt on this hypothesis. Methane is a contributor, 'short term'. Problem seems to be if methane increases rapidly (orders of magnitude) after a 'tipping point', either through sub-ocean clathrates or permafrost melt-out, it results in a short, rapid burst of extra heating, which could then start another tipping point, such as the melt-out of the GIS; so it's more of a 'disaster scenario' than the more subtle, more damaging & more persistent CO2 warming. Think in terms of timescales - how soon can we expect uncontrolled feedbacks?

wili

"if methane increases rapidly (orders of magnitude) after a 'tipping point', either through sub-ocean clathrates or permafrost melt-out, it results in a short, rapid burst of extra heating, which could then start another tipping point"

Nicely put, Fsmbrown. (Though, of course, a significant pulse will itself contribute significantly to total GW directly.)

But note again that Schindell and others have put the GW potential of methane at 105 times that of CO2 over decadal time scales, 35 x CO2 over a century.

I need to ask over at RC whether those numbers are being reconsidered.

Here's the article name and link: “Improved Attribution of Climate Forcing to Emissions“

http://www.sciencemag.org/cgi/content/abstract/326/5953/716

When asked if the article was still right in 2010 on RC, Gavin Schmidt, one of the authors, affirmed accuracy of the findings.

crandles

Re " I should've worded that better as I didn't mean to imply that what we saw happen this year was a negative feedback due to low NH snow extent."

We might speculate that ice cracking in February like it did in Feb 2013 is a negative feedback. This seems likely (also cracking in April is likely to be positive) but I would suggest it is still just speculation rather than established.

Hans Gunnstaddar

http://www.weather.com/news/weather-forecast/california-record-driest-year-20131115

Colorado Bob, as an update to an earlier discussion on drought conditions in CA, the link above is an article that came out on 11/15/2013. The first 10 months of 2013 (Jan.- Oct.) have been the driest since 1895 (118 years). The wettest months are coming up, Dec, Jan.& February. We also get a lot of rain sometimes in March. So the tale of the tape are these next few months.

So far, other than one storm that came through in November, there's been nothing. Those blocking highs may finally becoming entrenched even during Winter.

Ggelsrinc

Fwmbrown, that seems about right in my opinion, but I've never been in a lab measuring it, so is it 1 or 5? Atmospheric samples from the past have had time to change ppb methane to ppm CO2.

My impression is methane isn't that much of a problem, but I don't want to bet the future of the human race, nor all those fine animals living on my present day Earth, based on that impression.

When we send people out to space and they say "Houston, we have a problem", we fix it. When our planet is telling us there is a problem, we don't fix it, even when there are obvious options. We have Armies on our planet that can stand down, stop the wars and concentrate on fixing our Earth. We can "weld" ice together using liquid nitrogen or figure out a smarter way to prevent ASI leaving the Arctic. What we need is one government with territory up there to turn it's ass around and make a stand.

wili

Searching around a bit, it looks like some recent papers give a range of values for the global warming potential of methane, rather than just one number.

For example, "methane has a global warming potential that is 20–40 times higher than that of carbon dioxide (CO 2) on a 100 year timescale"

http://www.sciencedirect.com/science/article/pii/S0278434313002604

Note that the high end of this range is even higher then that given by Schindell et alia.

Ggelsrinc

Methane is a gas and gases taught us the Periodic Table of elements. The capacity of methane to behave as a greenhouse gas can be measured very accurately, just like CO2. It's conversion to CO2 can't be accurately measured. The amount of methane in past atmospheres can be accurately measured.

Methane is simply one of the ways the Earth gets rid of carbon, so go figure!

Is it possible for the Earth to give up so much carbon during a short and quick warming spell, I'd say yes, but it is not probable.

Regardless, when you find yourself going too fast, you slow the hell down. You don't test the planet you need to survive on to it's limits taking the human race and all other life forms to such extremes, because it's insane.

Erimaassa.blogspot.com

via Tenney Naumer, likely a quite objective article on this contestissue with methane: http://www.fairfaxclimatewatch.com/blog/2013/08/methane-blind-spot-could-be-much-bigger-than-we-think.html

Shared Humanity

While it is true that methane breaks down relatively rapidly in the atmosphere, the products of that breakdown are CO2 and H2O. Both of these are greenhouse gases. Color me as less than optimistic about this mechanism and its contribution to our well being.

Ggelsrinc

Methane also has the ability to get to the stratosphere, so it's conversion to CO2 and H2O has other effects on feedbacks, namely clouds.

I don't dismiss methane's role as an important greenhouse gas, but I don't see evidence of it ever having a role as some people claim during ice age times. I think there were events of bolide impacts releasing large amounts of methane in the past, but that's just speculation.

Neven

Thanks, wili, I'll add this video to the blog post.

Hans Gunnstaddar

According to Ms. Shakhova there is 50 gigatons of methane in the atmosphere, and the ESAS contains 100's to 1000's of gigatons of CH4. Only 1% would need to escape to double atmospheric methane.

She says in so many words the undisturbed ice use to keep these methane hydrates sealed, but now the ice is gone part of the year, the wind churns the water disturbing the hydrates with some releasing. She says it's only a matter of decades for it's complete release, but someone on her team in the background whispers to her it could release anytime, which she then reluctantly agrees.

Sure would be nice if a test could be done with a column of water with hydrates down 50 meters to test different water temperatures and rates of mixing to determine at what point it releases en masse.

wili

Hans, at minute 4:22 she says (and it is written up on the screen) that the total amount of methane in the current atmosphere is 5 (not 50) billion tons.

The 'someone' is actually a senior colleague, Igor Semiletov, who, iirc, has been working in this area even longer than Shakhova.

50 billion tons is the amount that she has claimed could be released at any time. I get the impression that she came up with that figure just by randomly coming up with a small fraction of the total estimated amount locked in the seabed.

TenneyNaumer

wili, that was not my comment over at Eli's, more's the pity - that was from anonymous.

I am deeply disappointed in those there who insinuate that Shakhova is a self-promoter and charlatan.

For one thing, her husband, Igor Semiletov, is much less conservative than she is.

He is the leader of the expeditions and has spent even more time there than she has.

Why Shakhova is the target of invective puzzles me. No one has directed such comments in Semiletov's direction. I am tending toward the MCP card.

wili

methanetracker.org showed November 26, 2013, peak readings as high as 2392 ppb near Greenland.

Hans Gunnstaddar

wili, acknowledged, 5 not 50. My post would have had more impact with 5, so wish I'd gotten it right. In any case, this situation is the type of news that should be on the front page.

2392 ppb near Greenland! Those numbers are starting to push higher.

Hans Gunnstaddar

I realized later that by writing "on the front page" could be misconstrued, so what I meant was; main stream media front page news on a newspaper, magazine or a lead story on TV news.

Kevin O'Neill

One of the constast themes I see from detractors of Shakhova and Semiletov is the idea of shallow depth hydrates. Equilibrium Pressure-Temperature equations tell us that hydrates should be at depths of 200m or deeper. This is why detractors say that no pulse is possible - the thermal diffusion required to reach those depths would take millenia.

But shallow depth hydrates are known to exist in the arctic. One of the papers cited by Shakhova nad Semiletov is Gas and Possible Gas Hydrates in the Permafrost of Bovanenkovo Gas Field, Yamal Peninsula, West Siberia by Evgeny M.Chuvilin, Vladimir S.Yakushev and Elena V.Perlova. This paper shows hydrates at depths of 60m to 120m. Chuvilin was also the lead author on Experimental investigation of gas hydrate and ice formation in methane-saturated sediments that states:

ice formation in pore space when residual water freezing in hydrate-containing sediments stabilizes gas hydrates even when pressure reduction occurs. As a result, gas hydrate can exist in the pore space of frozen sediments for a long time at pressures considerably lower than equilibrium values. So relict hydrates can be encountered all over the cryolithozone.

The existence of hydrates outside the equilibrium zone seems an accepted fact in Russian hydrate research, but seems highly dubious to most non-Russian climate scientists.

Blaine

@Kevin:
~200m of water column is really the absolute limit of stability at cold temperatures. At freezing it's ~300m.

Where natural gas is being produced, however, there's often a significant overpressure. At large scale, the pressure can reasonably run up to the equivalent depth of rock column, or ~3x higher.

This gives minimum formation depths from the surface on land of ~66m for the cold limit and ~100m at freezing.

If we're looking at above freezing at a depth of 100m which is generally representative of the East Siberian Continental Shelf, this we need at least ~66m more of rock.

This gives a thermal diffusion time scale of t = 66^2 / thermal diffusion coefficient. Plugging in a normal number for rock of 10m^2/year (large variance) gives ~440 years. So, yes, waiting for the temperature change to propagate takes a long time.

I think that what most people are missing here is that the normal state is an example of self-organized criticality. If gas is being produced steadily, the rock/ice/methane calthrate mass is ALWAYS close to fracturing strength. If there was no gas escaping, the pressure would just go up. State change can occur due to pressure change just as easily as due to temperature change.

Melt the top 10-20m of meters of permafrost, and the overpressure in that depth disappears, lowering the pressure beneath the permafrost. This will cause fractures extending downwards from the top of the permafrost. If the temperature is above the ice melting temperature, the pressure change alone will melt the top layer of calthrates, further continuing the process. Once there is flow from deeper, geothermally warmed layers, this heat will expand the fractures. With pre-Anthropocene temperatures, the dropping bottom pressure would eventually stop the transport and cause everything to freeze up again, and the system would be mostly quiescent until the next cycle.

This process goes on naturally all the time, but the eruptions of methane usually do not all occur at the same time, which has the potential to be the case with a large-scale surface melting trigger.

Kevin O'Neill

Blaine - "~200m of water column is really the absolute limit of stability at cold temperatures. At freezing it's ~300m."

You state the classic limits per the P-T calculations. You need to research "meta-stable methane hydrates." The Russians began predicting their occurrence in the early 1980s. By the 90's they were able to create meta-stable hydrates under laboratory conditions and also found them in the real world.

Experimental investigation of the possibility of relict gas hydrates formation in frozen sediments

Or just about anything by Chuvilin related to methane

The soil porosity seems to be the key factor. What it means is they've found hydrates at very shallow depths - as little as 60m (50m water column, 10m sediment core).

Fairfax Climate Watch

Archer's handy visualization tool for methane release and impact: http://climatemodels.uchicago.edu/slugulator/slugulator.doc.html

Twemoran

While I hate to see the internecine war taking place at RC I've read enough over the years to convince myself that S&S are on the right side of the dispute.
Those that have a much better understanding of the situation than I were willing to give them the use of a Nuke Ice Breaker - and that's an expensive toy to deploy if you don't think that their position has legitimacy.
Possible higher temperatures or less ice cover in the early Holocene are negated by the much colder temperatures retained in the recently inundated permafrost.
The shallow bottom of Hudson Bay shows pingos post dating grooves left by iceberg keels, so clathrates have been erupting in that area since the ice sheet disintegrated. If shallow clathrate formation is impossible how were these features formed?
We've been assured that the Storegga Slide wasn't caused by a clathrate blowout by BP, who then were given the OK to drill in the area - somehow I find that less than reassuring.
Terry

john_mann

Haven't read all comments but I came to this study through the Guardian online. I punted a question to Dr Shakhova and received a helpful reply. The gist is that the Siberian continental margin contains a lot of coal and this, along with geothermal heat is producing heat from below. And specifically that groundwater provides a significant mechanism for melting from below.

It may be that if sediments are sufficiently continuous, permafrost melting may reach through to this groundwater and cause circulation from the surface to the bottom of the underwater permafrost layer.

Then you'd have melting from top and bottom.

This may be a quicker process than simply warming seas would suggest.

Blaine

@Kevin:
Thanks for the link. Obviously soil chemistry would have some effect, but I hadn't known quite how large it is, particularly effect of salt causing freezing, which is obviously opposite from water ice. The strongest temperature effect in your link is for calthrate formation in the small amount of residual brine after most of the intra-pore water has frozen. Your earlier quote indicated to me only slowing of disassociation due to low initial permeability further lowered by ice formation, which will also leave some stranded calthrates, but is a different process than an equilibrium shift.

Low-pressure calthrates could disassociate relatively quickly, but they do seem to be more the exception than the rule, and I wonder how much methane flux they actually constitute, and whether the are abundant to result in a flux which is greater than those from clathrates on the ice, water and methane only phase diagram boundary.

For all that it is a millennial time-scale process, deep ocean calthrates can also begin disassociating relatively quickly. Any small warming will cause at least some of them to disassociate relatively quickly, and deep-ocean warming can begin within decades of the forcing, even if it takes longer to complete. I've already argued that East Siberian calthrates at the normal phase diagram boundary aren't really safe from at least partial release at shorter time scales due to pressure and hydrological change originating at the surface.

wili

Thanks all for a great discussion of this important/scary issue.

I just wanted to point out for youngsters (or squares '-)) who might have missed it that Neven's title is a musical allusion:

http://www.youtube.com/watch?v=iqvU5CVHHmk

jdallen_wa

I *still* say clathrate decay will not be a discontinuous event. That is to say, we w I'll see steadily increasing methane emission, but it should be incremental rather than abrupt. You can't evade physics, and it will take energy to cause clathrates to decay.

Kevin O'Neill

jd - that may well be, but there are other equally plausible scenarios.

Clathrates can melt from both the top and the bottom. Methane can accumulate in pockets from bottom melt. In the ESAS we have a frozen 'lid' of permafrost sitting above. Break or dislodge that lid and you get pulses of methane. We know this happens to a certain extent already - methane seeps are common near fault zones where a pathway to the surface is opened.

So the pulses of methane depend not on melting all the way down to the clathrates, but enough melting of the permafrost lid to open up pathways for pockets of methane already freed from their clathrate cages to escape.

wili

At about minute 25 of this press conference they mention that there is a large influx of bottom-dwelling creatures farther and farther into the Arctic.

http://www.youtube.com/watch?v=dZZsTgl-jHQ

These are likely to disrupt the permafrost 'cap' that KON just talked about in ways that it has never been disrupted before, thus accelerating its breakdown faster than the purely physics-and-chemistry-based models would suggest.

jdallen_wa

Yes and no, wili. It is unlikely macro fauna will disturb anything below the benthic layer. They certainly will affect that. Microflora/fauna I'm not so sure of, but similarly have doubts that will alter anything past the first meter or so of sediment. As the clathrates are concentrated far deeper than that, it is unlikely that the activity of bottom dwelling creatures will affect that mechanically.

wili

" the clathrates are concentrated far deeper than that" In some places.

Meanwhile, CC has a new piece on the Arctic Report Card.

http://www.climatecentral.org/news/fingerprints-of-arctic-warming-seen-throughout-region-16835

Verify your Comment

Previewing your Comment

This is only a preview. Your comment has not yet been posted.

Working...
Your comment could not be posted. Error type:
Your comment has been posted. Post another comment

The letters and numbers you entered did not match the image. Please try again.

As a final step before posting your comment, enter the letters and numbers you see in the image below. This prevents automated programs from posting comments.

Having trouble reading this image? View an alternate.

Working...

Post a comment