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New observations find underwater Arctic Shelf is perforated and venting methane

Posted on 6 March 2010 by John Cook

One of the positive feedbacks from global warming is the thawing of Arctic permafrost. This releases methane, a greenhouse gas over 20 times more potent than carbon dioxide, into the atmosphere. Investigations into Arctic methane have tended to focus on land permafrost. However, there are also vast amounts of methane held underwater in the East Siberian Arctic Shelf (ESAS). This encompasses over 2 million square kilometres, three times as large as the nearby Siberian wetlands, which have been considered the primary Northern Hemisphere source of atmospheric methane. Underwater permafrost acts as a lid to restrain methane stored in the seabed. Until now, it was thought the permafrost was cold enough to remain frozen. However, recent observations have found that over 80% of the deep water over the ESAS is supersaturated, with methane levels more than eight times that of normal seawater (Shakhova 2010). More than half of the surface water is supersaturated also. The methane venting into the atmosphere from this one region is comparable to the amount of methane coming out of the entire world’s oceans.

To find out what was happening in the East Siberian Arctic Shelf, field measurements, ice expeditions and a helicopter survey were conducted to measure methane levels in ESAS waters. They took 5100 samples from 1080 stations, the largest database for any ocean methane study. They found widespread supersaturation over the region. Most of the bottom waters are supersaturated and over half of surface waters are supersaturated. In some areas, the saturation levels reached at least 250 times that of background levels in the summer and 1,400 times higher in the winter.

Methane Levels in East Siberian Arctic Shelf, deep waters and surface waters
Figure 1: Summertime observations of methane levels in the ESAS. Top is dissolved methane in deep water. Bottom is dissolved methane in surface water (Shakhova 2010).

To find out how much methane is escaping into the atmosphere, they measured the flux of methane at the ocean surface. Methane levels were elevated overall and the seascape was dotted with more than 100 hotspots. A helicopter survey further confirmed this, finding methane levels were 5 to 10% greater at 1800 metres height. Methane is not only being dissolved in the water, it's bubbling out into the atmosphere.

Yearly flux of methane venting into atmosphere over East Siberian Arctic Shelf
Figure 2: Yearly flux of methane venting into the atmosphere over the ESAS (Shakhova 2010).

These findings tell us the large underwater permafrost "lid" over the East Siberian Arctic Shelf is clearly perforated and methane is escaping to the atmosphere. Why is this a concern? The impact of positive feedback from ESAS methane is not currently included in climate model projections. However, we can deduce the role of methane feedback by looking at past climate change. About 11,600 years ago, the planet warmed very suddenly. This corresponded with strong increases in atmospheric greenhouse gases, especially Arctic methane (Petrenko 2009, Nisbet 2009). This indicates that the permafrost is sensitive to warming temperatures, having released it's methane in the past. This gives us much reason to be concerned about the trajectory of the vast methane stores leaking from the East Siberian Arctic Shelf.

Update 7 Mar 2010: Real Climate offer some good perspective on methane feedback which echoes the theme in CO2 is not the only driver of climate:

"CO2 is plenty to be frightened of, while methane is frosting on the cake. Imagine you are in a Toyota on the highway at 70 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 80 miles per hour instead of 70. 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."

Update 12 Mar 2010: Thanks to Charles Brock who alerted me to a paper published mid-2009, Observational constraints on recent increases in the atmospheric CH4 burden (Dlugokencky 2009). Key results (noting that this is based on data ending in 2008):

Measurements of atmospheric CH4 show that, after a decade of near-zero growth, globally averaged atmospheric methane increased during 2007 and 2008... Near-zero CH4 growth in the Arctic during 2008 suggests we have not yet activated strong climate feedbacks from permafrost and CH4 hydrates.

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Comments 1 to 50 out of 70:

  1. Daisym, John clearly explained the mechanism through which AGW is melting arctic ice and allowing methane to be released from the benthos. It isn't that complicated. The thawing of terrestrial tundra permafrost is having the same effect. There is underwater permafrost because during the last ice age, sea level was lower than it is now. The permafrost was created, then it was submerged when sea level rose. Try googling "underwater permafrost" and you can learn all about it.
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  2. Is there a temperature record for the water around the underwater permafrost? I would be curious to see the trends.
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  3. This new work is interesting and a bit scary. It will be interesting to see if any trends are detected in the next few years. But... Neither of the two papers to which you have linked support clathrate methane as the primary driver of sudden warming during the Younger Dryas, although they do not rule it out as part of a larger GHG feedback. A better example for the clathrate gun hypothesis might be the PETM.
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  4. Sry, Should be "sudden warming at the END of the Younger Dryas".
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  5. There is strong evidence that the Permian Extinction Boundary-where 95% all marine life died out-was caused by the melting of methane clathrates. Anyone else just a little bit scared yet?
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  6. The wikipedia article on atmospheric methane is pretty good (IMHO) and it has a table that may help to put some big picture perspective on this news. Approximately 3% of total methane added to the atmosphere is listed as coming from oceans (I'm not sure if there is now ~6% if these latest results are applied). Wetlands (including rice agriculture) account for 37%. Farm animals account for 19%. There are other contributors readers might find interesting. Anyway, the most optimistic thing I can think to write is that we have pleny of scope to cut back anthropogenic emissions elsewhere. Halving beef production (or trapping the gas of cows) should easily compensate for even a doubling of the amount of methane released from this area. Right?, I ask hopefully. Finally, does the paper indicate how sea life is responds to all this supersaturated water? Methane reacts with oxygen in the water, so presumably this region is anoxic. Right?, I ask somberly.
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    Response: ...does the paper indicate how sea life is responds to all this supersaturated water?

    No, it doesn't look at impacts of the rising methane. It's mainly concerned with the measurement of methane levels in the water and atmosphere above the East Siberian Arctic Shelf.
  7. While it is true that the amount being released now in the ESAS is small compared to the total methane release rate, the scary thing is that this area alone contains (estimated) twice as much methane as is contained in the atmosphere right now. We should be wary of such a large reservoir becoming unstable especially since the permafrost is so close to the freezing point. Of course we can't really say right now that the methane field is destabaliz-ING because there is no significant record. But I do think that we are at the point where any sane person would buy just a little insurance.
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  8. "About 11,600 years ago, the planet warmed very suddenly." How fast is suddenly? Thanks, Jerry
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  9. Jerry at 13:16 PM on 6 March, 2010 A bit long in the tooth but still useful: "Around 14,000 years ago (about 13,000 radiocarbon years ago), there was a rapid global warming and moistening of climates, perhaps occurring within the space of only a few years or decades. In many respects, this phase seems to have resembled some of the earlier interstadials that had occurred so many times before during the glacial period. Conditions in many mid-latitude areas appear to have been about as warm as they are today, although many other areas - whilst warmer than during the Late Glacial Cold Stage - seem to have remained slightly cooler than at present. Forests began to spread back, and the ice sheets began to retreat. However, after a few thousand years of recovery, the Earth was suddenly plunged back into a new and very short-lived ice age known as the Younger Dryas. Although the Younger Dryas did not affect everywhere in the world, it destroyed the returning forests in the north and led to a brief resurgence of the ice sheets. This map by D. Peteet shows the possible distribution of Younger Dryas cooling around the world. The main cooling event that marks the beginning of the Younger Dryas seems have occurred within less than 100 years, according to Greenland ice core data (Alley et al. 1993). After about 1,300 years of cold and aridity, the Younger Dryas seems to have ended in the space of only a few decades (various estimates from ice core climate indicators range from 20 - 70 years for this sudden transition) when conditions became as warm as they are today. Around half of the warming seems to have occurred in the space of a single span of 15 years, according to the latest detailed analyses of the Greenland ice core record (Taylor et al. 1997)." From this: A quick background to the last ice age More background on ice core techniques here: End of the Last Glacial Period Inferred from Trapped Air in Polar Ice (pdf)
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  10. I'd expect sea water overlying ancient frozen wetlands to be supersaturated with CH4 irrespective of temperature (or am I vastly mistaken?). I'd therefore expect some of this to be escaping into the atmosphere. Are we dealing with a true increase in the rate of methane release (the inferred scenario) or are we seeing a lot of methane in the Arctic because we've only recently started looking for it? Tom W says we 'can't really say right now that the methane field is destabilising because there is no significant record.' I think this is the crucial question. At the same time, as parts of the world get drier and we see decreases in wetlands and tropical wetlands (not that I consider this desirable), we may have a counterbalancing decrease in CH4 release elsewhere. Does anyone have any idea how the two processes might balance out? I note also that CH4 degrades (eventually). Do we know anything about the dynamics of degradation versus release into the atmosphere? Finally, did atmospheric CH4 increase at the end of the last great warming mainly because of warming or do we suspect other mechanisms contributed significantly? If so, are any of these relevant to today's situation?
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  11. The implication of this article--that warming ocean waters are melting submarine permafrost--is certainly scary and is, I would guess, the most plausible hypothesis. Nevertheless, I was surprised to see so little discussion of the deep geology of the ESAS in the article. I would ask: 1) Do we know for sure that the methane is biogenic or could it be thermogenic (deeply sourced)? Perhaps some chemical analysis of the gas to see what traces of ethane, propane and so on are present might be helpful. 2) Are the "hotspots" (an unfortunate choice of term because it implies unproven locally elevated temperatures) associated with underlying geological features such as growth faults in deltas or diapiric/folded shale ridges (such are observed in the Canadian Beaufort Sea and in the Caspian Sea and are associated with deep gas seeps and mud volcanoes)? 3) On Figure 2B, the concentration of dissolved methane is highest over a bathymetric high. Is this due to the fact that relatively shallow waters have warmed more or is the high reflecting anomalous deep geology in some way?
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  12. chriscanaris said: "Are we dealing with a true increase in the rate of methane release... or are we seeing a lot of methane in the Arctic because we've only recently started looking for it" Those are interesting questions for the disinterested. Those concerned with the unintentional consequences of AGW have brought up the spector of Arctic methane repeatedly for 30 years. Those consequences have now been measured. The result is 'ouch'. Against that concern, and those results, you want to ask the semantic 'gosh, how did this happen' game?? Here is my response: We predicted it. If it is actually happening, the burden of proof is on YOU to provide an alternate explanation. Failing that, you have actually, just through your question, disqualified yourself from ever having asked it. I'm simply pointing out here, that the asking of questions does not, by itself, constitute scientific inquiry. If it did, we would never get anywhere. Somewhere, in a cloistered room, a coven of monks is still trying to count the number of angels that can fit on the head of a pin. And when they get their count we will hopefully determine whether Copernicus was right or not. And I don't think the result of their count constitutes the proper pervue of SkepticalScience.com
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  13. Ah, the old clathrate gun hypothesis. http://en.wikipedia.org/wiki/Clathrate_gun_hypothesis Then again, if the Navy was studying undersea excavation in permafrost just maybe the other guys already have buried cables and what not for anti-submarine hydrophone nets. That would create long rips in the seafloor miles long. http://www.dtic.mil/srch/doc?collection=t3&id=ADA165939
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  14. chriscanaris at 13:36 PM on 6 March, 2010 The fate of methane in the atmosphere is known with excellent confidence. See information about sources and sinks including atmospheric degradation of methane here: Atmospheric methane and global change (pdf) Andy S at 14:11 PM on 6 March, 2010 This introductory bit of the paper will help answer your questions: "The terrestrial and continental shelf regions of the Arctic contain a megapool of carbon in shallow reservoirs (1–3), most of which is presently sequestered in permafrost (4, 5). Sustained release of methane (CH4) to the atmosphere from thawing Arctic permafrost is a likely positive feedback to climate warming (5, 6). Arctic CH4 releases are implied in both past climate shifts (7, 8) and the renewed growth of contemporary atmospheric CH4 (9, 10). Observed Arctic warming in early 21st century is stronger than predicted by several degrees (fig. S1A) (11–14), which may accelerate the thaw-release of CH4 in a positive feedback. Investigations of Arctic CH4 releases have focused on thawing permafrost structures on land (2, 4–6, 15, 16) with a scarcity of observations of CH4 in the extensive but inaccessible East Siberian Arctic Seas (ESAS), where warming is particularly pronounced (fig. S1A) (11). The ESAS (encompassing the Laptev, East Siberian, and Russian part of the Chuckchi seas) occupies an area of 2.1 x 106 km2, three times as great as that of terrestrial Siberian wetlands. It is a shallow seaward extension of the Siberian tundra that was flooded during the Holocene transgression 7 to 15 thousand years ago (17, 18). The ESAS sub-sea permafrost (fig. S1B), which is frozen sediments interlayered with the flooded peatland (18), not only contains comparable amounts of carbon as still land-fast permafrost in the Siberian tundra but also hosts permafrost-related seabed deposits of CH4 (19). Moreover, ESAS sub-sea permafrost is potentially more vulnerable to thawing than terrestrial permafrost. In contrast to on-land permafrost, sub-sea permafrost has experienced a drastic change in its thermal regime because of the seawater inundation. The annual average temperature of ESAS bottom seawater (–1.8° to 1°C) is 12° to 17°C warmer than the annual average surface temperature over on-land permafrost (18, 19). A physical implication of combined bottom-up geothermal and top-down seawater heat fluxes is the partial thawing and failure of sub-sea permafrost and thus an increased permeability for gases. We consequently hypothesized that CH4 is released from seabed deposits to vent extensively to the Arctic atmosphere."
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  15. ubrew12 The concluding sentence of the Shakhova et al article reads "To discern whether this extensive CH4 venting over the ESAS is a steadily ongoing phenomenon or signals the start of a more massive CH4 release period, there is an urgent need for expanded multifaceted investigations into these inaccessible but climate-sensitive shelf seas north of Siberia." Making such comments at the end of an article or asking similar questions on a blog (as chriscanaris did with his first question) constitutes a proper sceptical approach to communicating and understanding science, and it's not pointless nit-picking.
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  16. doug_bostrom: Thanks for the link to the Wuebbles article.. I don't doubt for a minute that there is biogenic methane trapped by permafrost layers in shallow waters of the Arctic Ocean; I've seen the same thing in the Canadian Beaufort Sea years ago. Nor do I doubt the plausibility of the hypothesis that predicts that warming waters could melt the permafrost seal and release the gas to the atmosphere. It's just that there's a lot of complex deep geology that also can generate methane and leak it to the surface. One might expect that if was deep geology controlling the gas release, then the effect would be variable over the area (as was observed), whereas a buried shelf of tundra might have a more areally constant concentrations of released CH4. Of course, if it can be demonstrated that the release of gas is a recent phenomenon and the release rate increases as the ocean warms then my questions become moot. In any case, the new observations of enormous emissions of methane, as they stand, are alarming enough.
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  17. East Siberian Arctic Shelf releases mpore methane than all the rest of the world ocean... ... but how much methane is released from Siberian land? It would be interesting to compare release of methane from the Arctic Sea with the methane released from the Siberian Land. Anyone has the data?
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  18. Hi folks, New on here but have been an occasional poster on RC for years. This is a development I hoped I would never see. I guess the key work - in the field - now has to be to monitor the outgassing rate and watch for any increases above what we already see. Geologically speaking, the area is primarily an epicontinental platform, although there are some small sedimentary basins containing up to 6km of post-Cretaceous sediments - these are potential hydrocarbon sources, although the widespread outgassing recorded suggests a more widespread source for the methane. Cheers - John
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  19. Andy S, the reason that surface concentrations (and thus atmospheric release) of methane are highest in shallower waters is BECAUSE they are shallow... there is less water for the methane to disperse through. We've been seeing increased methane leaks all around the Arctic for years, but it hasn't been a huge concern because they generally get nowhere near the surface... the methane accumulates in deep water and then is dispersed by currents. Methane leaks in shallower water are a different matter. They can saturate the water all the way up to the surface and thus start leaking into the atmosphere as well. As to geological processes producing methane... look at the ocean floor map. What could possibly produce that much methane that consistently over that large an area? We're not seeing isolated spots of methane release, but rather an entire region producing methane. That clearly points to release from the permafrost due to warming. It also helps to explain why other studies have found that atmospheric methane levels have been increasing the past few years.
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  20. Thank you for the Wuebbles link, Doug. I found it fascinating. I note the complex relationship between atmospheric methane, and its degradation by the OH radical formed from atmospheric ozone and water. I note the multiple sources of methane including termites. There seems to have been a substantial transient rise caused by the Mt Pinatubo eruption. Drying wetlands indeed may cause decreases in atmospheric methane. Agricultural land may be a less efficient a CH4 sink - certainly a concern. I found myself hearkening back to an earlier discussion on the role of stratospheric water vapor in global warming, in which the argument was advanced that water vapour played a minimal role as a driver of climate change. However, if methane is a source of considerable concern, then water vapour may be much more important than we think in being both a weak greenhouse gas and a major factor in the degradation of a potent greenhouse gas. Similar considerations would apply to ozone - also a greenhouse gas. I guess the greatest challenge facing climatologists lies in integrating the sheer complexity of multiple feedback loops and predicting which loop will become the dominant driver of climate change. Doug – your earlier comment on the ice age raises many questions. You quote from: http://www.esd.ornl.gov/projects/qen/nerc130k.html "After about 1,300 years of cold and aridity, the Younger Dryas seems to have ended in the space of only a few decades (various estimates from ice core climate indicators range from 20 - 70 years for this sudden transition) when conditions became as warm as they are today. Around half of the warming seems to have occurred in the space of a single span of 15 years, according to the latest detailed analyses of the Greenland ice core record (Taylor et al. 1997)." I went to the site and read inter alia: "The Earth entered several thousand years of conditions warmer and moister than today; the Saharan and Arabian deserts almost completely disappeared under a vegetation cover, and in the northern latitudes forests grew slightly closer to the poles than they do at present. This phase, known as the 'Holocene optimum' occurred between about 9,000 and 5,000 years ago (8,000-4,000 14C years ago), though the timing of the warmest and moistest conditions probably varied somewhat between different regions. " I also read: "The unstable nature of the Earth's climate history suggests that it may be liable to change suddenly in the future. By putting large quantities of greenhouse gases into the atmosphere, humans are exerting pressure on the climate system which might produce a drastic change without much prior warning. As the geologist W.S. Broecker has said, "Climate is an angry beast, and we are poking it with sticks"." Now do not get me wrong. I am certainly not in favour of pumping more CO2 into the atmosphere just for the sake of it. Pumping out less is very likely a good thing for multiple reasons (AGW being but one of them). However, in the light of this background, can we confidently say that current climate behaviour is unprecedented and thus anthropogenic? Likewise, can we predict that a specific intervention will prevent climate change? Can we say that all the sequelae of climate change (anthropogenic or otherwise) are bad? The disappearance of the Sahara desert would be very welcome to those who eke out their livings on its edges. The melting of the permafrost may open up a food basket. The "angry beast" may have its gentler side and like all "angry beasts" have its proper place in the scheme of things. Thus, we decry the threatened extinction of tigers (a concept which would have bewildered many a South East Asian villager a century or two ago). I appreciate this may sound a touch provocative. However, the recent Copenhagen debacle suggests that until such questions are addressed, many developing nations will be unwilling to risk jeopardising their economies and limiting emissions via strategies that inhibit growth. Equally, if AGW is what we fear it to be (and it may well be if the "angry beast" lives up to its reputation), should resources be directed towards adaptation and mitigation?
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  21. To continue to put this in perpective, the Perspectives section in the same Science issue describes the amount of CH4 presntly being lost from this region as "negligible". http://www.sciencemag.org/cgi/content/summary/327/5970/1211 Given this paper is about feedbacks it's interesting that in the same issue of Science there is a paper which may further our knowledge of the role of Stratospheric Water Vapor in climate feedback. http://www.sciencemag.org/cgi/content/abstract/327/5970/1219 This paper suggests that atmospheric water vapour can partly explain accelerated warming from 1980 to the end of the 1990's and the flattening of temp through the naughties. They attribute 30% of temp rises in the 1990s to changes in water vapour, something neglected up to now. It concludes by saying it is not possible to say whether this "represents a feedback to global average climate change or a source of decadal variability."
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  22. HumanityRules, the Solomon 2010 paper is discussed elsewhere on this site.
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  23. I don't think that the release of methane from the Arctic sea bottom or land permafrost will give huge problems. The previous interglacial, the Eemian shows much higher land temperatures (+ 5 C in Alaska), forests growing until the Arctic ocean (probably no or little permafrost), an ice free ocean (at least in summer), and halve the Greenland ice sheet melted away. Despite this higher temperatures, the methane level reached not more than about 700 ppbv (see http://www.ferdinand-engelbeen.be/klimaat/eemian.html ), while humans now induced up to 1900 ppbv (with little increase in the past decade). Thus even if the Arctic seawater temperature should rise (of which there is little information for the Arctic), the possibility of huge changes in methane releases and/or increase of the atmospheric methane levels due to such release is rather remote...
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  24. TOP writes: Then again, if the Navy was studying undersea excavation in permafrost just maybe the other guys already have buried cables and what not for anti-submarine hydrophone nets. That would create long rips in the seafloor miles long. Look again at the top panel of figure 1. CH4 is elevated over an area on the order of a million km2 (John cites a figure of 2 million km2 at the top of this post). Digging a few trenches for submarine cables isn't a realistic explanation for this.
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  25. PS: ubrew12 Your comment has been niggling away at me (as I'm sure you intended)! You say, 'Here is my response: We predicted it. If it is actually happening, the burden of proof is on YOU to provide an alternate explanation. Failing that, you have actually, just through your question, disqualified yourself from ever having asked it.' At the risk of going off topic, I'm really not sure what you're getting at. Why can't I ask questions? I might actually want to know the truth. You allude to Copernicus (who incidentally was a cleric if not actually a cloistered monk). Copernicus was wrong! His theory based on the circular motions of planets around the sun did not accord with astronomical observations (though it was a brilliant and revolutionary hypothesis and very close to the truth). Ptolemy's Copernicus assigned circular motions to the planets around the sun because the prevailing paradigm equated the circle with perfection - hence hence he assumed planetary motion around the sun would be circular. In fact, the older Ptolemaic geocentric hypothesis with its elaborate cycles and epicycles better fitted existing observations. Kepler hypothesised that the planets moved around the sun in elliptical orbits giving rise to his eponymous laws of planetary motion, which have stood the test of time. So, to come back on topic, I think the purpose of this forum is precisely to ask questions and gain understanding, not to posture or label. I don't pretend to the genius of a Copernicus or Kepler. However, if the then prevailing paradigms had prevailed, our understanding of the universe would be vastly impoverished. And so to set the record straight, the scientific establishment of the time (which also happened to overlap with the Church) took issue with Galileo (not Copernicus) when he propounded the Copernican system effectively insisting that he had 'disqualified [him]self from ever having asked it,' precisely because 'We predicted it.' Incidentally, the notion that mediaeval cloistered monks actually debated the number of angels that could dance on the head of a pin seems without foundation - there's an interesting Wikipedia article on the topic.
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  26. I tried to do a "methane" movie which may be thought provoking. I have been advised by Pieter Tans at NOAA that the satellite sensor SCHIAMACHY data should be interpreted with care, there are many potential sources of bias etc when looking at regional sinks/sources. Remember this is atmospheric Methane, and I apologise for the small text and other issues, but it covers a lot of ground (pun there somewhere!) http://www.youtube.com/watch?v=S_IJMuOtrD8
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  27. The SCIAMACHY satellite data seems to have given us our best insight into localized atmospheric methane levels, it shows methane hotspots for siberia and China. There are no hot spots for methane along the coastal region of this sea (where most of the hotspots are highlighted by this paper). I's unfortunate the satellite data for the sea itself is of poor quality.
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  28. darn peter you beat me too it.
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  29. So whats the problem with the SCIAMACHY data because the Bremen guys seem to love it and it's been written up in Nature and other Journals.
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  30. chriscanaris, unfortunately when there's such a generic (poorly focused) comment full of questions the response need to be quite long as well. So it will be a bit unreadable; I'll try to be schematic and short. "can we confidently say that current climate behaviour is unprecedented and thus anthropogenic?" The link between "unprecedented" and "anthropogenic" does not exist. Even if not unprecedented current warming may still be anthropogenic in origin. We can be quite confident that current warming is anthropogenic. This is the best aproximation we can give, the truth does not exists in science. "can we predict that a specific intervention will prevent climate change?" If the cause of current warming is anthropogenic, increasing the cause will increase the effect, more or less. Will it be enough? Not sure, but it's worth to give a try; in any case we will at least limit the effect. "Can we say that all the sequelae of climate change (anthropogenic or otherwise) are bad?" This question is equivalent to ask how much warming is affordable. Today it's currently assumed that it is 2 °C, but any threshold is obviously (and easily) questionable. Though, we can confidently say that BAU will take us much beyond it. So we are back to the previous question, we need to limit the effects anyways. "The disappearance of the Sahara desert would be very welcome to those who eke out their livings on its edges." This is not a question but it's a central point. Not of science, though, it's political. No doubt that some (not much) waming will benefit high latitudes, but people living nearby today already warm and semi-arid regions will fare worst. How can we balance the two? Physical sciences have nothing to say, it's upon politics. What we do know, again, is that too much warming isn't good for anyone. So, notwithstanding the well recognised uncertainties, business as usual is not an option.
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  31. HumanityRules at 01:00 AM on 7 March, 2010 I agree the images look great and papers are detailed and persuasive. http://www.iup.uni-bremen.de/sciamachy/NIR_NADIR_WFM_DOAS/477schne.pdf http://www.atmos-chem-phys.net/9/443/2009/acp-9-443-2009.pdf (~45 Mbyte download!!) Some of their images are in the YouTube movie, along with paleo data etc. Pieter is simply advising care, but this is prudent as SCIAMACHY is the first global methane mapping system capable of detailed regional analysis. It has been checked with a few ground based measurements and differences are reported to be in the low percentage units. Once the Ibuki sensor on GOSAT gets beyond the preliminary results (calibration/validation) stage I guess they can cross check: http://www.jaxa.jp/press/2009/05/20090528_ibuki_e.html#at2
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  32. RealClimate is taking a sober view of this, which is probably the correct scientific approach. It is not the "runaway" effect that might be feared (yet!). http://www.realclimate.org/index.php/archives/2010/03/arctic-methane-on-the-move/
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  33. RealClimate stated that sea effects of methane venting are dwarfed by land effects - peatlands and agricultural wetlands (explain why Siberia and China show up on the satellite mentioned in Humanity Rules #27). It also explains why a focused sea study was needed to note this effect.
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  34. John, what are the units in Figure 2 describing the flux of methane to the atmosphere? Thanks.
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    Response: Good question and sorry about the delay in response. My initial thought was they were milligrams per square meter per day (mg/m2/d) as those were the units used elsewhere in the paper. But the numbers seemed too high so I sent an email to the author of the paper - I only heard back from her today (12 March). Her response:

    "Units are mg/m2/d. He is right - the numbers are high, but this is what paper was about."

  35. chriscanaris at 19:57 PM on 6 March 2010 Chris, we can with confidence (thanks to isotope ratios) say that we've increased the amount of C02 in the atmosphere by a large amount. By uncontroversial physics we can make confident predictions about what that C02 will do to the radiative budget of the planet. Beyond that we begin more to enter the realm of predictions with probabilities of greater or lesser strength. The probabilities we see are nearly all pointed in the wrong direction. We even now appear to be seeing early confirmation of some of these predictions*. Now, much of the argument about this topic is centered on economic impacts on developing nations, the assumption being that by replicating our behavior in the developed world, so-called third world nations will find themselves on a conveyor belt to success. This assumption however ignores the fact that we're on the tail end of the fossil fuel bounty that allowed us in the developed world to catapult to the position we're in today. We in the developed world are increasingly concerned that we need substitutes for fossil fuels not because we're necessarily concerned about system impacts of fossil fuel waste products but because fossil fuels are inexorably approaching exhaustion. Demand curves never tell a happy story about our supply. So I think the notion that by tackling our bimodal energy problem (C02 and diminishing supply) we're going to harm developing nations is fundamentally flawed, because if developing nations are lured into adopting our anachronistic method of powering development this will bring them harm in the form of a false leap forward, followed by instability and collapse as the energy supplies they used as a springboard vanish. I think it's more conservative and forward looking to assist developing nations with work of bypassing fossil fuels as much as possible, somewhat akin to what has happened with copper versus wireless telephone plants. Regarding possible benefits of rearranging geography by accident, I don't think rolling the dice and waiting to see what happens is a responsible course. * Fingerprints of man-made climate change
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  36. Great video, Peter Hogarth ! This kind of videos should be released by NOAA, NASA and ESA every month so we can all follow the plumes of methane in the atmosphere!
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  37. Peter Hogarth @26 -- thank you. I read somewhere that Arctic sea ice melts on nearly the same schedule as it did 20 years ago, but that the regrowth is delayed to a greater extent. The explanation was that the reduced ice extent allowed the Arctic Ocean to accumulate more heat, so it took longer to freeze. Looking at how methane seems highest only in July-October in the northern hemisphere, I wonder if that's an additional factor. I'd be curious to know if the late release of methane also contributes significantly to this trend.
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  38. Steve L, thus far it is more the other way around... ocean heating through the summer is the reason that frozen methane is melting and being released at that time. Yes, this methane would then contribute to MORE ocean heating, but thus far the amounts being released aren't sufficient for any significant impact.
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  39. I want to apologize to chriscanaris for the abruptness of my earlier response. I'm not a frequent commenter on SkepticalScience, and perhaps now you know why. However, particularly on the subject of methane release, I find it increasingly hard to distance my scientific self from my selfish humanness. No other consequence of AGW has, in my mind, the potential to exert itself so completely and utterly onto my physical person, and, more urgently, onto those of my children. The estimated costs of AGW remediation are 1-2% of global GDP for the next 50 years. To save us this cost, we are debating the future magnitude of polar methane release. A release that, RealClimate notwithstanding, could still in its worst manifestation lead to human extinction. I would remind our readers what a 'standup job' scientists have made of Polar Warming predictions in the past: as few as two years ago they predicted NO polar ice field contributions to sea level rise this century. Now they are saying 'no big deal' to polar methane release. Sorry, but there's something in there about 'fool me once, fool me twice'. This is the topic, the only topic, about which people like me lose sleep. Methane clasts in deep ocean deposts exist in an unstable configuration of high pressure and low temperature. Assure me they won't bubble up and extinguish life on earth, as many earth scientists posit they have done in the past. Failing that, sign up, post-haste for a 1-2% hit on global GDP. You can laugh at me later if its all a false alarm.
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  40. Thanks ubrew12 - no hard feelings. I seem to have provoked a few responses :-) Riccardo: you say, 'This is the best approximation we can give, the truth does not exists in science.' You then say,'We can be quite confident that current warming is anthropogenic.' For the record, I would very likely agree with the latter but not the former statement. I think it bodes us ill to forget that science is a search for truth via a process of positing hypotheses (IE, asking questions). I'm not a climate scientist but I like this site and the opportunity to ask questions. Socratic dialogue is a means of ensuring that we are asking the right questions and edging closer to the truth. Of course, what countries do with the scientific data comes down to political decisions. You then say, 'What we do know, again, is that too much warming isn't good for anyone.' This however begs the question. How much warming is too much? I think it's important to work out as best as we can whether the processes in evidence today have passed a tipping point or whether they are reversible. Otherwise, we risk huge investment in low yield strategies (emission lowering only) as opposed to, for example, strategies aimed at both lowering emissions and mitigation/adaptation. Doug, you may well be right that we have come to the end of our fossil fuel driven boom. Interestingly, countries such as India seem to recognise this - they seem to be moving towards nuclear energy. This has given rise to some interesting responses from Australia which doesn't want to sell India its uranium because the Indians have not signed the non-proliferation treaty. However, short of massive subsidies from the first world, I can't see countries such as Bangladesh or Burkina Faso moving towards either nuclear energy or renewables - they're just not in that league. However, they deserve a leg up to prosperity. As for 'rearranging geography by accident,' I think we need to be very wary of assuming that our level of knowledge and understanding suffices to ensure our interventions will evade the 'law of unintended consequences.' I'm not arguing for doing nothing or 'business as usual' - just hoping that in asking questions, I (and others) might learn something of value. I loved the methane maps. I was fascinated to see that one of the major 'hot spots' was in West Africa on the Gulf of Guinea. I was born childhood in Ghana where I spent my childhood - the West African coastline comprises coastal wetlands giving way to stretches of savanna and tropical rain forest. The other major hot spot is the Amazon basin. Unfortunately, these are precisely the conditions that give rise to endemic malaria and a host of other tropical nasties that kill lots of people and undermine quality of life of many more. Interestingly, malaria was also endemic in southern Europe, eg, in Italy, until Mussolini drained the Pontine Marshes outside Rome. Today, this would be considered ecological vandalism - however, the Italians seem perfectly happy to be free of malaria at the expense of biodiversity. The Wikipedia article on the Pontine Marshes ends with the following: 'The Battle of Anzio [WWII] left the marsh in state of devastation; nearly everything Mussolini had accomplished was reversed. The cities were in ruins, the houses blown up, the marshes full of brackish water, the channels filled in, the plain depopulated, the mosquitoes flourishing and malaria on the rise. The major structures for water control survived and in a few short years the Agro Pontino was restored. In 1947, the province of Littoria, created by Mussolini, was renamed to Latina. The last of the malaria was conquered in the 1950s, with the aid of DDT. Today a duct system runs through the dried-out area. Wheat, fruit and wine are cultivated in the Pontine region. The "Agro Pontino" is a flowering landscape with modern cities with both pre-war and post-war architecture. By the year 2000, about 520,000 inhabitants lived in this formerly deserted region. The Battle of the Swamps, however, is never quite over; without constant vigilance: dredging the channels, repairing and updating the pumps, and so on, the enemy would soon return. The spectre of distant problems remains: the prospect of chemical pollution of the environment, DDT-resistant mosquitoes, and medicine-resistant strains of malaria.' In other words, humans are always rearranging geography whether by accident or design in accordance with prevailing values. I sometimes feel that we in the First World operate on a double standard. Allowing the Third World to remain in grinding poverty is unjust. Moreover, prosperity helps create a milieu in which people value and care for the environment - witness the ecological disasters of the former Soviet Bloc Rustbelt. I doubt very much you or I would want to live in 18th Century London (just before anthropogenic CO2 began to rise) with its narrow streets piled high with horse manure, human excrement, and refuse with cholera epidemics, polluted air, and a host of other nasties to boot.
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  41. 34.Ian Forrester at 05:13 AM on 7 March, 2010 Flux is the movement from one fluid to another so I guess it's a ratio sort of thing, no actual units. I found that scale puzzling. Particularly the use of colour. Goes up to pink then back to green and upto pink/red. Leads to a confusion of where the hotspots are. Also the strongest hotspot is a a river delta. Is there another process going on here?
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  42. HR, I'm afraid that is not right. Flux should be given in "amount" per area per time. It should be able to give actual numbers and amounts and not "ratios". Check out Fick's first law of diffusion
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  43. ubrew12 at 12:18 PM on 7 March, 2010 I just spent some time w/Google scholar rummaging around using the search term "methane stability zone." There's a term we use, "cold comfort"; maybe now we need to add an ironic "warm comfort" to our parlance. This methane seems to exist in a state of equilibrium balanced by opposing forces. Reduction of sea level due to glaciation destabilizes methane due to reduced pressure, but so does rising temperature. Methane takes a long time to get locked up but can break out of jail in very little time given half a chance. On the other hand it seems to be "metabolized" fairly rapidly. It looks as though how rapidly methane is liberated and whether it can contribute significantly to a warming pulse depends on how quickly currently stable methane is engulfed by conditions that don't support stability. This of course makes me think of the rapidly changing Arctic ice scene. Over and over again it seems we're reminded of how various dynamic features of Earth such as ice sheets are tuned for the instant they inhabit. It's too easy to forget that none of these features are engineered, none of them are purposely built with reserve strength.
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  44. HumanityRules at 13:51 PM on 7 March, 2010 "Also the strongest hotspot is a a river delta. Is there another process going on here?" Relatively warm water from the river, it's mentioned in the article.
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  45. #40 chriscanaris, I think what Riccardo was getting at with his statement about truth is that no scientist can claim knowledge of absolute truth, in contrast to faith-based thinking. Of course we are seeking the truth, but EVERY scientific theory is subject to revision or to even being discarded if data don't support it. You have to change your mind when the data demand it. All of science is just our best approximation to the truth. Socratic dialogue is fine, but scientific questions are not answered by dialogue -- they are answered by data. You talk about posing hypotheses, but that is only a small part of science. Testing hypotheses by experiment, observation is the critical part. Any new theoretical development also must be put to the test. Sometimes, breakthroughs come from new theory or models that allow us to test new things we couldn't test before. Later, you said: "I think we need to be very wary of assuming that our level of knowledge and understanding suffices to ensure our interventions will evade the 'law of unintended consequences.'" I find this a bit ironic given that you go on to cite examples of rearranging geography, and thus recognize that we are intervening already. We have been intervening in the climate system for at least 250 years, with dramatically increasing global effect from the geometric growth of our energy consumption. What are the unintended consequences, now and in the future, of our experiments in changing atmospheric composition? It is wise to be wary of overestimating our knowledge, but the same wariness must be applied equally to our understanding of what our business as usual is doing.
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  46. Jeff: Socratic dialogue is precisely a process of posing hypotheses and testing them against data. I confess that the more I look at the whole AGW question, the more I am overwhelmed by its complexities. We must be wary of our natural human tendency to reductionist thinking and thus avoid confronting the multiple contradictory strands of evidence (no, I'm not denying temperature rises to date or increases in anthropogenic CO2 - that part of the science looks very convincingly settled). However, as this site so richly illustrates, there's so much more to climate change than CO2. You're perfectly right in highlighting the irony in my giving examples of rearranging geography. The irony was intended. As a species, we have enormous difficulties dealing even with 'simple' issues like running an equitable national health system in a prosperous economy let alone dealing with climate change. However, we have to do the best we can with what data we have and take a careful punt. Consequently, we need to be honest about what we do and don't understand - otherwise, our reductionism does devolve into faith based thinking. We also need to be honest about the ad hoc nature of our responses to the challenges we have faced over successive generations. These are not always as coherent as we would like to pretend. Human history has never been 'business as usual' unless we accept that lurching from crisis to crisis is what we do most often. The trick lies in finding the balance between overhasty responses and paralysis.
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  47. chriscanaris at 13:47 PM on 7 March, 2010 Chris, this is going way off topic, but if we're truly concerned about grinding poverty in the third world we'll gift those places with universal education, equal rights for women, and encouragement and means to practice birth control. None of those things are particularly energy intensive, or expensive for that matter. Short of fully exploiting those proven methods for lifting people from the mud, we'll have to employ and continue forever employing brute force energy, in ever increasing amounts. Fixing the problems of the third world really has not much to do with energy supplies; one could argue that supplying the third world with ample food, consumer goods and energy without supplying the three basics of education, equality and population control would be a fool's errand.
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  48. chriscanaris, the question you continue to ask ("how much is too much") is more philosophical than scientific. Whatever answer one may give is always questionable, as i said before. Science may tell you that beyond a certain temperature you'll get this or that effect; if you further increase temperature those other effects will come into play; and so on. So, how much is too much? Here you go into philosophiical and/or political and/or ethical ground. If i got it right, you do not question AGW theory. You agree that temperature is rising due to human activities and that it will have a negative impact on human welfare. If this is true, you questions appears to be more on resilience and "affordable damage" the on the science of climate. Why you should you find an answer in climatology? Science already told us what we can confidently say about the evolution of climate, it's time to make a choice an to take up the responsibility (and the costs). Remember, doing nothing or postponing the choice is a choice as well, with the same burden of responsibility and costs.
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  49. I can see this is all going to get bigger than Ben Hur so I'll say no more on the topic after this (collective sigh of relief from all and sundry). I'll leave off biting the bait on large scale family planning beyond noting that family size tends to decrease following increased prosperity and not vice versa. However, when it comes to education and health, our foreign aid budgets are laughably miniscule. I do think we have to ask ourselves about the resilience of natural systems - in my own discipline, medicine, and specifically psychiatry, treating the the illness without treating the whole patient and taking into account their strengths (ie, resilience) is poor medicine indeed. Furthermore, treating the whole patient (planet) calls for consideration of people's wants and aspirations including the aspirations of the third world. Our failure to do so no doubt contributed to the failure of Copenhagen. At this point, of course, the argument enters the realm of philosophy (which is not the same as faith). However, we can't escape philosophy. The only reason we are putting so much energy into this discussion is because we would like a good life for ourselves and our children's children (a philosophical notion) for which a well functioning planet is a sine qua non. If we were not looking to the self-interest of humanity, future climatological outcomes are no more than a scientific curiosity on par with past climatic events.
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  50. Chriscanaris says: "Furthermore, treating the whole patient (planet) calls for consideration of people's wants and aspirations including the aspirations of the third world. Our failure to do so no doubt contributed to the failure of Copenhagen." It seems clear (to me, at least) that global warming will cause disproportionate harm to third world people. First-world people, on average, have a greater cushion of resources to help them adapt to rising sea-level, regional changes in rainfall, summer heatwaves, etc. Much of the population of the third world, however, lives close to the edge of survival, such that any change in conditions means disaster for them. This is the crux of the ethical problem presented by AGW, in my view.
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    Response: "It seems clear (to me, at least) that global warming will cause disproportionate harm to third world people"

    This view is borne out in the peer-reviewed literature although not just for the reasons you suppose. See The distributional impact of climate change on rich and poor countries (Mendelsohn 2006):
    "We predict that poor countries will suffer the bulk of the damages from climate change. Although adaptation, wealth, and technology may influence distributional consequences across countries, we argue that the primary reason that poor countries are so vulnerable is their location. Countries in the low latitudes start with very high temperatures. Further warming pushes these countries ever further away from optimal temperatures for climate sensitive economic sectors."
    In addition, developing countries happen to be those most vulnerable to sea level rise, as examined in The impact of sea level rise on developing countries: a comparative analysis (Dasgupta 2008).

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