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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

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Comments 66701 to 66750:

  1. Climate Solutions by dana1981
    Colin -"Each side continues to present seemingly endless amounts of scientific data" That is tone-trolling nonsense and completely false. Now you may lack the background knowledge to distinguish between science and pseudo-science (the fake-skeptics), but that lack of information does not make the two sides equivalent. I hope you see the logic here. 97% of publishing climate scientists accept that global warming is real, based on the overwhelming mountain of evidence, and only 1% disagree. That should tell you something, even if you cannot distinguish between climate science and climate quackery.
  2. Climate Solutions by dana1981
    Colin, A quick check with the search function at the top of the page gave this article on Skeptical Science about costs. Perhaps if you read the article there it will answer your questions. If not, it is a better place to ask the questions you have. The short answer is that economic studies show it is much cheaper to reduce CO2 than to deal with the problems afterward. It is also much cheaper the sooner you start to reduce CO2.
  3. CO2 lags temperature
    @ 129CBRider If I understand you correctly, you are of the persuasion that believes in cycles, and that the next cycle of an ice age is imminent. Of course, that would be ignoring a very great deal of established physics, based on centuries of research, by many thousands of scientists. Not to mention that these are the same physics that underpins the technology of today. So I recommend that Newcomers, Start Here and then learn The Big Picture, plus The Big Picture Look at Global Warming. I also recommend watching this video on why CO2 is the biggest climate control knob in Earth's history. As an FYI, assertions lacking support in the science and the literature tend to get ignored. Failure to back up repeated assertions with source citations tends to get comments moderated or deleted.
  4. Climate Solutions by dana1981
    Colin "As an average citizen, with a vote, I think it is only reasonable that I learn the cost before I accept the prescription." But being (un)willing to pay certain costs for particular prescriptions has nothing to do with the diagnosis. Surely our personal or social willingness to pay costs is related entirely to how seriously we take the diagnosis we've been given and the prognosis if we don't take appropriate action. Most of this site is about diagnoses and prognoses.
  5. Climate Solutions by dana1981
    Colin discussing the best cure and its costs is what we all would love to do. But how can we if one side of the political arena still deny the need of any cure?
  6. Katharine Hayhoe's labour of love inspires a torrent of hate
    TOP, 1. There clearly is consensus among climate scientists that AGW is real. I would venture to guess that you are correct that the ECI statement does not reflect the mainstream view among evangelicals. 2. The signers' position on biblical inerrancy is irrelevant. 3. There was no measurable AGW when the Bible was written, so one wouldn't expect statements on it. 4. The biblical passages used in the ECI statement were ones that support the ideas of caring for the poor and practicing good stewardship of Earth's resources. These principles are widely accepted as being in accord with the Bible as a whole, and with orthodox Christianity.
  7. Katharine Hayhoe's labour of love inspires a torrent of hate
    I have just read the RTCC interview, the level of intolerance is unbelievable. The national anthem of the USA speaks of "land of the free and home of the brave". For me Hayhoe is clearly the brave one and it seems to me that a lot of people in the USA think that the "free" part is only applicable to others having exactly the same ideas as they have. This looks like the return of the Spanish Inquisition, another era of Enlightenment is needed. I'm not a believer myself, but it is good to hear that science and a personal religious belief don't have to exclude each other. I hope that Katharine Hayhoe doesn't give up and also will be able to enjoy her climate-work.
  8. Katharine Hayhoe's labour of love inspires a torrent of hate
    Interesting discussion. Regarding the use of "cognitive dissonance", I think it is being used incorrectly. I believe it more accurately means that feeling of confusion and discomfort when you have distinct bits of information in your head, you believe them to all be true, and yet they conflict with each other. It is a feeling associated with conflicting information, but is not the information itself, and it only makes itself evident when the conflict is recognised. For instance, if someone you trust tells you that a good friend has done something awful. It can be identified with statements to the effect that, "I just don't know what to believe." or, "There must be some other explanation." (Hmm, all of a sudden Merchants of Doubt comes to mind.) It provokes a response based on emotion; as Rob Painting has noted, an easy way out of the dissonance is to reject part of the information. I think Gingerbaker exemplifies the tendency to think in Us and Them terms. It is important to break the habit of doing this; otherwise, it the division only widens. Then you end up with irrational scenarios where whatever the other side says must be wrong because the other side said it. My guess is that Gingrich's views on other issues are compatible with Hayhoe's, and so she felt no compunction against helping him. In her mind, I'm guessing, religious faith, party affiliation, and belief in science are independent; that appears not to be the case for many people.
  9. Gillett et al. Estimate Human and Natural Global Warming
    MMM - we're considering doing an analysis of Michaels 2002. It's a relatively low-impact paper though - only Michaels ever seems to cite it, so it's just a question about whether it's worth the effort. It might be interesting though. Paul Magnus - there could be a small natural contribution to the warming (solar and/or volcanic). Gillett found a very small natural contribution from 1961 to 2010.
  10. Climate Solutions by dana1981
    Fair enough John, I stand corrected. But I think you've missed my point... This web site, and every other site I've seen is solely focused on promoting a particular view. Each side continues to present seemingly endless amounts of scientific data, bolstered by it's own interpretation, to convince the reader. Each side ridicules the other as being uninformed, biased, unqualified etc etc. This very web site has sunk to the adolescent level of name calling... "Baked Curry", "Christy Crocks", "Lindzen Illusions". However, my point is simply that nobody seems to want to discuss the cost of the cure. As an average citizen, with a vote, I think it is only reasonable that I learn the cost before I accept the prescription. I can't understand why that concept seems so difficult...
  11. Katharine Hayhoe's labour of love inspires a torrent of hate
    In regard to her manifesto and the signatories:
    1. The same standard regarding a Biblical position to GW should be applied as is presented here: There is no consensus. It obviously isn't settled in the evangelical community that one can hold to a Biblical position and the position presented in ECI Statement is certainly not mainstream.
    2. While there are 500 signatories, a few of which are well known, many come from the liberal side of evangelical Christianity which doesn't necessarily hold to the Bible being inerrant and inspired.That there are 500 isn not indicative of any kind of shift in thinking. 500 or 5000 signatures could probabably be obtained objecting to the manifesto and Hayhoe's position.
    3. The Bible itself makes no statements about AGW one way or the other.
    4. The use of the Bible in the ECI manifesto is "cherry picking" and not acceptible in the Biblical hermeneutics or science.
      If the canon of Scripture is considered as an organic whole, rather than an accumulation of disparate individual texts written and edited in the course of history, then any interpretation that contradicts any other part of scripture is not considered to be sound.Biblical Hermeneutics
  12. CO2 lags temperature
    Which causes what it kinda irrelevant if you consider the direct relationship between average global atmospheric temperatures and atmospheric CO2 content tells us that the next glacerization will be as extreme as the current rise in CO2 content, throwing us into an Ice Age the likes of which history has never seen, possibly only leaving a band around the equator without ice.
  13. Puget Sound, Under Threat From Ocean Acidification, Put on "Waters of Concern" List
    Manwichstick - Tatoosh Island (at the entrance to the estuary containing Puget Sound) has seen a drop in pH much lower than fossil fuel emissions would suggest, so clearly there is some other aspect which is not yet understood. It happens to be a region of strong natural upwelling (of highly acidified deep water), but not just the 'imported' Pacific oyster is struggling there - wild mussel populations are poised upon the brink too. This is indeed very,very serious, and it's disappointing that an agency tasked with protecting the environment has to be taken to court to even acknowledge the damage being done.
  14. Puget Sound, Under Threat From Ocean Acidification, Put on "Waters of Concern" List
    Yum oysters. We excel in denial. No problem here. We just ignore inconvenient facts. And that pesky EPA will soon be gone. The Puget Sound region is the land of falling bridge engineering failures and ignored science. Seattle is digging a below sea level traffic tunnel right on the waterfront and across an active fault. We are home to the Gates Foundation that heavily invests in coal. And Boeing is happily building planes for decades into the future - even tho US airports are starting to ground planes in summer heat. And remember it was a good thing Mt St Helens erupted on a Sunday - the very day that denialists like the sleep in. Move along. We call Seattle the Emerald City. Nothing to see here. No problems. Nothing to worry about. Pay no attention to that EPA behind the curtain.
  15. Katharine Hayhoe's labour of love inspires a torrent of hate
    Maybe some of you are aware of this effort http://creationcare.org/blog.php?blog=19 to "engage" with global warming, motivated by Christian concern for the earth & for the "least of these my brethren."
  16. Arctic methane outgassing on the E Siberian Shelf part 1 - the background
    Spikes in methane at the end of the last an previous ice periods withing the present 2.5m year ice age were not observed but spikes in Carbon dioxide were. Since the end of these ice periods was in sinc with Milankovitch obliquity, it is unlikely that the rise in CO2 was the cause of the start of the interglacials but rather the result. Since methane, on a geological time scale, is instantly converted to CO2, we would be unlikely to pick up a methane spike (in ice cores) but rater to observe it as a Carbon dioxide spike. The likely source of this methane would be the accumulation of methane clathrate under the continental ice sheets with the methane, over the 100,000 year life of the ice sheet coming from underground shale, coal and oil plus the anaerobic break down of organic material This would be "0ld" carbon and so carbon dating from the end of the most recent ice period might show some carbon dating anomalies. http://mtkass.blogspot.com/2011/08/end-of-ice-ages.html
  17. Puget Sound, Under Threat From Ocean Acidification, Put on "Waters of Concern" List
    I believe a .1 change in pH is equivalent to a 30% increase in concentration.
  18. Katharine Hayhoe's labour of love inspires a torrent of hate
    Gingerbaker... Actually, I think it makes total sense that she would write a chapter on climate change for Gingrich's book. Gingrich is also very religious and I think it's with the religious that she wants to convey the science of climate change. It's just sad that it's turned into yet another scene of hate-mongering from extremists.
  19. Katharine Hayhoe's labour of love inspires a torrent of hate
    Katherine has been fighting the good climate fight for a long time. She voluntarily spoke at the Ontario Association of Physics Teachers conference and did not ask for any money in return. Along with her parents, she has been in the science education business for her whole life as far as I can tell. She has been working "from the inside". Years ago she addressed the REP (Republicans for Environmental Protection) - I didn't such a thing existed - . Her lecture may still be available online somewhere. I'm not sure how religious she was before marrying her minister husband, but none-the-less she helps those in Texas to reflect on what the moral course of action ought to be. I am saddened to hear about her getting the hate mail. I think she is awesome and approaching this very nobly. I also think she maybe credited for the expression "climate weirding" in her efforts to help increase the climate literacy of those she tries to inform. I predict that she will keep doing what she has been doing and not slow down because of the personal attacks.
  20. Katharine Hayhoe's labour of love inspires a torrent of hate
    Dr. Hayhoe might have been impressed by Newt's own words on the environment in "A Contract with the Earth," Gingrich and Maple, 2007: I am convinced, however, that the environment is an issue that transcends politics. Americans deserve candor on this subject: why the environment is so important to all of us, and why the time has come to act on what we know. But he was sitting squarely on the fence at that time: We recognize that global climate change is supported by a wealth of scientific data ... However we still cannot be certain about the variance introduced by distinctly human activities. Should human behavior be a cause, to any extent, it wouldn't be surprising, given the role that human beings have played in other environmental events ... He was, once upon a time, almost a radical green: The greatest dangers to biodiversity on the planet today are poor people cutting down tropical forests for money and killing endangered species for meat. Wealthy people can afford to protect the forests and protect endangered species. Only to find that this particular Newt could switch from green to red in a heartbeat: The candidate immediately stated that global warming “hasn’t been totally proven” and even if it were, he would still oppose a cap-and-trade solution to combat carbon emissions which, as Gingrich argued, would “turn over the entire economy to the EPA.” He offered the following analogy to explain his position. “The Dutch face the problem of oceans. They decided to build dikes instead of lowering the sea.” Poor choice of examples, as the Dutch are hardly standing still on climate change: As sea levels swell and storms intensify, the Dutch are spending billions of euros on "floating communities" that can rise with surging flood waters, on cavernous garages that double as urban floodplains and on re-engineering parts of a coastline as long as North Carolina's. The government is engaging in "selective relocation" of farmers from flood-prone areas and expanding rivers and canals to contain anticipated swells. Perhaps not being included in Newt's book will, in the long run, work out as a good thing for Dr. Hayhoe.
  21. Katharine Hayhoe's labour of love inspires a torrent of hate
    I sincerely hope Dr. Hayhoe is following this. This is obviously a difficult time for you and your family, but know that regardless of what mean-spirited, hateful and ideological people might believe, you have truth, honour, integrity and science on your side. You also have the support of many, many people who respect and admire you and your work. Thank you for everything that you do and for standing up to bullies like Marc Morano and Rush Limbaugh. Stay strong.
  22. Katharine Hayhoe's labour of love inspires a torrent of hate
    Rob Honeycutt: "Gingrich previously had made very clear statements about AGW being a concern and there's even a commercial with Gingrich and Boxer talking about their common position on it. It's only since he became a presidential candidate that he shifted his position. " I understand that, Rob, but it doesn't help me to understand why she would donate her efforts to support Newt Gingrich, his political goals, or those of the Republican party. None of which have any history of the slightest inclination to help "...Our global neighbours, the poor and disadvantaged, the people who don't have the resources to adapt". Do you think Hanson or Mann would write a book chapter - for free - for any perennial Republican candidate? I wonder whether her motivations to do this were not exclusively to promote climate change awareness, but rather also included political motivations typical of evangelical Christians, who vote very strongly Republican. If so, then I would argue that her religious and political affiliations might well be in severe cognitive dissonance with her claimed humanitarian and scientific goals. Not that there is anything wrong with promoting the dissemination of the scientific facts surrounding climate change, but doing it in the service of the Republican party, which has demonstrated its anti-science biases to anyone's satisfaction, simply doesn't jive with Hayhoe's professed missions.
  23. Katharine Hayhoe's labour of love inspires a torrent of hate
    She has my full support, although I am not an especially religious person. I believe in fair play. What Morano did was unforgivable. That is not the first time, though. Who on earth would actually want to be remembered in toasts, when they have departed, as a hate-monger? I do not recognise the motivations for this that he has. The world has always - when it has worked OK - followed science: this is how we started to cure diseases such as Smallpox. Morano's mode-of-existence, instead, seems to be to attempt to rubbish any facts that do not match up to his rather strange worldview. Hence Climate Depot. He should be ashamed of himself. I could not live with myself if I were responsible for that. And you are responsible for that, Marc Morano. You should, indeed, be ashamed of yourself, were it that you knew shame! So come - answer me - and justify your methods. Come and justify why you think encouraging hate-mail to hard-working people is somehow cool. Come and tell us why you splatter your front page with the email addresses of folk with the obvious intention of getting their inboxes cluttered with messages of hate. Come tell us why you think the whipping-up of hatred against gentle Christian folk is a bit of a laugh. And then we may have peace (as Theoden suggested to Saruman). Marc Morano, respond honestly. It's your call... John
  24. Puget Sound, Under Threat From Ocean Acidification, Put on "Waters of Concern" List
    What sort of pH changes are being talked about here?
  25. Katharine Hayhoe's labour of love inspires a torrent of hate
    It's really a damn shame that certain people have politicized climate science so much that a good and smart person as Hayhoe could receive so much hate mail for doing nothing more than providing a requested chapter on climate science. Something is very wrong with this picture. Kerry Emanuel recently also received a lot of hate mail, some of it targeting his wife, for saying that the political denial reactions to climate science sometimes make him feel ashamed to be American. Sometimes I feel the same way.
  26. Katharine Hayhoe's labour of love inspires a torrent of hate
    Gingerbaker... Gingrich previously had made very clear statements about AGW being a concern and there's even a commercial with Gingrich and Boxer talking about their common position on it. It's only since he became a presidential candidate that he shifted his position.
  27. Katharine Hayhoe's labour of love inspires a torrent of hate
    I have to say, I think that people like Katherine Hayhoe and Barry Bickmore are very likely the most important individuals in the entire climate debate. They are so important for starting to address the cognitive dissonance we see with conservatives and the religious. I can rattle off scientific research all day long and there are people who will never ever believe me because I am a liberal atheist. But Katherine and Barry are in a very unique position that helps advance the broad public acceptance of climate science. If you read these comments, Katherine, thank you for your work!
  28. Katharine Hayhoe's labour of love inspires a torrent of hate
    Why did an informed woman, who professes to have empathy for "Our global neighbours, the poor and disadvantaged, the people who don't have the resources to adapt" donate her efforts and expertise to provide arch Republican Newt Gingrich, of all people, with a campaign tool?
  29. Katharine Hayhoe's labour of love inspires a torrent of hate
    Misanthropes are running the aslyum. Clearly the true problem is our self-contempt and species contempt.
  30. Arctic methane outgassing on the E Siberian Shelf part 1 - the background
    Eric#16, You raise an interesting point. In the graph of atmospheric methane concentration posted by Tom C in #6, the years 1999-2006 are conspicuously flat. Since 2006, there's an equally conspicuous change in trend. Compare that with the graph below, showing US natural gas production: --source advanced fracking technologies starting becoming available about five years ago and boosted domestic gas production by almost 25% since 2006. The boom in unconventional shale gas made America the world's No. 1 producer of natural gas, when it passed Russia in 2009. Your link to Howarth 2011 makes a strong case that methane emissions from hydro-fractured shale gas production is significantly higher than from conventional gas. ... 3.6% to 7.9% of the methane from shale-gas production escapes to the atmosphere in venting and leaks over the lifetime of a well. These methane emissions are at least 30% more than and perhaps more than twice as great as those from conventional gas. The higher emissions from shale gas occur at the time wells are hydraulically fractured—as methane escapes from flow-back return fluids—and during drill out following the fracturing. As you suggest, it would be a very interesting study (albeit off-topic here) to compare volumes released from these two sources. Is it possible that as new gas production continues increasing, we are doubling down on methane? The great science experiment in the sky continues.
  31. Katharine Hayhoe's labour of love inspires a torrent of hate
    My congrats to Katharine. I hope other scientists follow her initiative.
  32. Katharine Hayhoe's labour of love inspires a torrent of hate
    See the website for her book, A Climate for Change and the LA Times interview. Her book for evangelicals, "A Climate for Change," sells tepidly because Christian bookstores won't stock it. At a senior citizen center in Lubbock, a man shaking with rage shouted an expletive-studded monologue about how the greenhouse effect doesn't exist. At a talk for Texas Tech business school students, her arguments were simply dismissed. At the end of any given talk, perhaps one person might tell Hayhoe she's convinced him of the scientific consensus on global warming. Some might say that we're known by the company we keep. Hmm, Hayhoe on one side; the likes of Limbaugh and Morano on the other. No surprise, Gingrich picked the wrong side.
  33. Arctic methane outgassing on the E Siberian Shelf part 1 - the background
    For anthropogenic methane production, that is tracked by the EPA (along with other non-CO2 GHG and their sector emissions sources) and is available replete with projections through 2020 here: http://www.epa.gov/climatechange/economics/downloads/GlobalAnthroEmissionsReport.pdf The specific methane emissions data you wish are available in Appendix A-2, starting on page 155. Other useful info + eye-candy is here: http://www.globalmethane.org/documents/analysis_fs_en.pdf Apologies, but I lack the time to do the comparison you seek.
  34. It's not bad
    Interesting article, thanks for the mental meal! A couple of questions: I'm in Australia - will we get *fewer* droughts as a result of global warming? (Thanks for the video link @muoncounter, was awesome). It's kinda important, given we've got a carbon tax as the current political football. Also, can it be predicted *when* (ie which season) increases/decreases in rain will occur? The true nightmare in OZ is a wet spring followed by a hot summer, as that means insane bushfires. However a dry spring/wet summer is awesome. Makes a huge difference! - What about refugees? How many millions of people are going to have to move? That's going to create a huge cost, surely. - Finally...ok, this one's creepy, but I have to ask. If (i) it's true that most human genetic diversity is in Africa, and (ii) Africa gets it in the neck, are we going to lose great wodges of genes that could be used for treating inherited diseases etc? I don't mean to treat people as harvestable cattle, but if it is a genetic loss, and pointing out the loss can reduce the likelihood of them being left to die, then it needs to be said...
  35. Gillett et al. Estimate Human and Natural Global Warming
    Er. What I meant to post was, given that Chip raised it, was that it would be interesting to look at Michaels 2002 and see how it held up with time. The last time I looked at it, I remember a third of the paper being devoted to how everyone was overpredicting the CO2 concentration increase because it had held steady at 1.5 ppm for the last 20+ years. Of course, in the 9 years since, CO2 concentration has gone up at >2 ppm, as many others were predicting beforehand...
  36. Gillett et al. Estimate Human and Natural Global Warming
    Tom: The data terminates in 2005 because I was trying to reproduce the BEST figure, which is a 120-month running mean, and therefore terminates 60 months before the end of the data in March 2010. The other datasets run until 60 months before Oct 2011, when I did the calculation. Sorry, I should have stated that. The land-masked CRU index does show substantial divergence from the BEST data over the last decade, if you look at the 12 month or even 60 month running means. In particular CRU gives substantially different results for any trend you calculate starting since 1998. However the differences are largely ironed out by the 120-month running mean. I suspect therefore that any calculation using the whole run of the data, such as the one described in this article, will be minimally affected by the choice of temperature data. (When I first started look at this a few months back you suggested adjusting the coverage the different gridded datasets to get an accurate indication of the effect of poor sampling in CRUTEM3 and ultimately HADCRUT. That was a good idea, since it is very simple and factors out all the complex issues of baselines and so on. I'm hoping to have the results in a week or two.)
  37. Katharine Hayhoe's labour of love inspires a torrent of hate
    You can well understand why she's being targeted by the hate-mongers. She is gorgeous, confident, bubbly and very articulate. Are you sure she's a climate scientist? Doesn't fit with this stereotypical image I have.
  38. Eric (skeptic) at 22:53 PM on 15 January 2012
    Arctic methane outgassing on the E Siberian Shelf part 1 - the background
    Daniel Bailey, thanks for posting that graph, I didn't mean to suggest that there is not a large (over 2.5x) manmade hockey stick. But I was wondering how much is caused by our direct emissions perhaps in China and unconventional gas production (http://www.sustainablefuture.cornell.edu/news/attachments/Howarth-EtAl-2011.pdf) and how much from the rise in Arctic temperature as described in the article? It seems to me that direct methane production predominates for at least two reasons, the lack of prior interglacial rise and the recent pause perhaps corresponding to the decline of the former Soviet Union (http://165.91.85.82/class/atmo689-gs/lectureweek4/2003GL018126.pdf). But what about the more recent resumption?
  39. Katharine Hayhoe's labour of love inspires a torrent of hate
    Disgusting how people can be so hateful and threatening when they can't face up to reality - especially those who would call themselves religious. Disgusting, too, how Gingrich dropped the relevant chapter just so he could appeal to the deniers within the Republican party. Hypocritical as well. Unfortunately, America is becoming a laughing-stock, politically speaking, where anti-science, religion and denial of reality is seemingly thought of as being the right qualities for a certain (largish ?) section of society.
  40. Katharine Hayhoe's labour of love inspires a torrent of hate
    Oh, just watched the second video. Damn, she's married.
  41. Arctic methane outgassing on the E Siberian Shelf part 1 - the background
    To clarify my post in #12 "The first problem is that in none of the glacial-interglacial transitions of the past 400,000 years has a sudden large methane-spike been recorded." Why should it? The glacial-interglacial are established through the periodical Milankovitch cycle, and methane values doubled.
  42. Arctic methane outgassing on the E Siberian Shelf part 1 - the background
    From above URL 5.3.4.3. Trace gas emissions from subsea permafrost Since the Arctic Climate Impact Assessment (ACIA, 2005), there have been recent advances in measuring and estimating large-scale emissions of carbon from the Arctic coastal seas (e.g., Shakhova et al., 2010a). These new studies have resulted in much higher estimates of carbon emissions than those from earlier studies, with more profound implications for feedback to the climate system. The destabilization of submarine permafrost has significant implications for global climate. Current estimates of the amount of CH4 that could be released from the Arctic continental shelf (7 million km2) during the short Arctic summer (100 days), based only on diffusive fluxes, is as high as 5 Tg of CH4 (Shakhova et al., 2010b). This is a considerable increase on the ~0.1 Tg previously estimated by Kvenvolden et al. (1993). The current estimate reflects the contribution of only a very small fraction of the total CH4 fluxes and other significant components exist. One such component is CH4 release during the deep autumn convection, which allows water from the East Siberian Arctic Shelf to mix from top to bottom (Kulakov et aal., 2003). A significant late-summer potential CH4 release to the Atmosphere might therefore occur during only a few weeks Another mechanism of CH4 ventilation is deep convection in the flaw polynyas (band-like ice-free areas), which form simultaneously with land-fast ice in November. Flaw polynyas reach tens of kilometres in width and migrate out of fast ice hundreds of kilometres northward (Smolyanitsky et al., 2003), providing a pathway for CH4 to escape to the atmosphere during the Arctic winter. Fluxes from the European Arctic polynyas are 20- to 200-fold higher than the ocean average and, as long as concentrations of dissolved CH4 in the bottom water do not exceed 50 nM, can reach 0.02 Tg CH4 a year A significant amount of CH4 could also be released during the ice break-up period from areas not affected by polynyas. In these areas, dissolved CH4 accumulates beneath the sea ice as it does in northern lakes (Semiletov, 1999). Additional release of CH4 via these mechanisms would contribute to an increase in the diffusive fraction of air-sea CH4 exchange, but the most important and still unmeasured component is ebullition. Assuming that ebullition might contribute to the total transport of CH4 in the East Siberian Arctic Shelf as much as it does in northern lakes (50% to 90%), the annual release might reach from 10 to 50 Tg of CH4. Note that this amount does not include non-gradual or sudden releases of CH4, which are likely to take place in some areas where hydrates decay (Leifer et al., 2006). The amount of CH4 that could theoretically be released in the future is enormous. The volume of gas hydrates that underlie the Arctic Ocean seabed is estimated at 2000 Gt of CH4 (Makogon et al., 2007). About 85% of the Arctic Ocean sedimentary basins occur within the continental shelf so that within the East Siberian Arctic Shelf alone, which comprises about 30% of the area of the Arctic shelf, hydrate deposits could contain around 500 Gt of CH4. An additional two-thirds of that amount (around 300 Gt) is stored in the form of free gas (Ginsburg and Soloviev, 1994). Because most submarine permafrost is relict terrestrial permafrost, the carbon pool held can be estimated from knowledge on current terrestrial carbon storage to include not less than 500 Gt of carbon within a 25 m thick permafrost body (Zimov et al., 2006a), 2 to 65 Gt of CH4 as hydrates (McGuire et al., 2009) together with a significant amount of non-hydrate carbon. The total amount of carbon preserved within the Arctic continental shelf is still debatable but it could be around 1300 Gt of carbon, from which 800 Gt is previously formed CH4 ready to be suddenly released when appropriate pathways develop. Release of only 1% of this reservoir would more than triple the atmospheric mixing ratio of CH4, probably triggering abrupt climate change, as predicted by modeling results (Archer and Buffett, 2005).
  43. Arctic methane outgassing on the E Siberian Shelf part 1 - the background
    RE .." the second problem is finding a physical mechanism by which such an abrupt release of that magnitude could actually happen: so far, on a subshelf environment where major undersea landslides are unlikely, nobody has proposed a detailed mechanism by which that could happen" Page 5 - 34 Processes in methane release from the seabed and subsequently from sea to atmosphere The possible sources of CH4 in the Arctic coastal seas include sediment microbial activity, natural seeps, and gas hydrate destabilization (Kvenvolden et al., 1993). Methanogenesis can occur at any depth (Koch et al., 2009). The present understanding of the mechanisms that control the current thermal state and stability of submarine permafrost and of seabed CH4 deposits is mostly based on modeling results. These results are very controversial and suggest a wide range of possible current states of submarine permafrost (Soloviev et al., 1987; Kvenvolden et al., 1992, 1993; Kim et al., 1999; Delisle, 2000; Romanovskii and Hubberten, 2001; Romanovskii et al., 2005; Gavrilov, 2008). Saline waters affect permafrost formation (Osterkamp, 2001), and according to Osterkamp and Harrison (1985) the reduction in thickness of ice-bearing permafrost determined by the salinity of sub-permafrost waters can be hundreds of metres. In addition, Delisle (2000) predicted that open taliks can form under the warming effect of large river flows. However, Romanovskii et al. (2000) and Romanovskii and Hubberten (2001) argued against downward destabilization of subsea permafrost and suggested that upward warming through the geothermal heat flux predominated. Destabilization becomes evident by the formation of CH4 migration pathways through the seabed (Kvenvolden, 2002). They appear as pockmarks, mud volcanoes, funnels, chimneys, and pingo-like structures, and they might not be morphologically specified (Hovland et al., 1993; Judd, 2004; Paull et al., 2007). Additional pathways could be via submerged thaw lakes, which by the time of inundation were underlain by taliks, thereby providing a vent (Romanovskii et al., 2005). In addition, depressions found in the East Siberian Arctic Shelf bottom topography could be interpreted as a typical thermokarst terrain similar to the landscape characteristic of the Siberian Lowland (Schwenk et al., 2006; Rekant et al., 2009). Subsea permafrost does not necessarily represent a rocklike, ice-bonded layer but is sometimes ice free under negative temperatures due to freezing-point depression by salinity, which allows gases to escape (Himenkov and Brushkov, 2007). A number of additional factors allow temporary permeability of submarine permafrost, and these include permafrost breaks due to thermal contraction, settling and adjustment of sediments, and endogenous seismicity (Osterkamp and Romanovsky, 1999). Gaseous CH4 can escape through the seabed into the water by means of air voids, channels of unfrozen water, and fissures within the ice (Biggar et al., 1998; McCarthy et al., 2004; Arenson and Sego, 2006). http://amap.no/swipa/CombinedDraft.pdf
  44. Arctic methane outgassing on the E Siberian Shelf part 1 - the background
    So my comment in #11 relates to "The first problem is that in none of the glacial-interglacial transitions of the past 400,000 years has a sudden large methane-spike been recorded."
  45. Arctic methane outgassing on the E Siberian Shelf part 1 - the background
    Pressurized laboratory experiments show no stable carbon isotope fractionation of methane during gas hydrate dissolution and dissociation ..measured δ13C-CH4 values near gas hydrates are not affected by physical processes, and can thus be interpreted to result from either the gas source or associated microbial processes http://onlinelibrary.wiley.com/doi/10.1002/rcm.5290/full
  46. What's Happening To Tuvalu Sea Level?
    Stephen, Firstly the article says:- "It just so happens that the western Pacific and Tuvalu in particular, are one such region where there is a large rise in sea level, much greater than the global average. See figure 3." Now you can't have one part of an ocean higher than anther part of that ocean without a continuous force to hold it there. Otherwise it just flows out until it is level. It is well known that winds cause the rise during la nina when the winds increase. Wind is the only effect that can be a long term cause of a localized sea level rise. Temperature or salinity differentials across an ocean are not sustainable due to eventual mixing. Referring to the diagrams above you can sea the sea level rise is localized and is also in the area that trade winds operate and effect. Just go back to basics and contemplate what could make the sea level locally higher, and also contemplate how high it can increase in relation to the ocean average before the force to outflow is just too great.
  47. What's Happening To Tuvalu Sea Level?
    Stephen - I came across one recent paper which suggests a strengthening of the easterly trade winds - which directly contradicts the Timmerman (2010) study which I cited. So future trends could see a further above-average sea level rise, or not.
  48. Stephen Baines at 16:05 PM on 15 January 2012
    What's Happening To Tuvalu Sea Level?
    Tealy "A point you need to consider is that the large sea level rise around Tuvalu is mainly due to the increased strength of the trade winds." But, what is your evidence that trade winds have increased on average in such a way to cause a long term change in sea-level? You need to cite some source before making statements like that.
  49. What's Happening To Tuvalu Sea Level?
    KR- A point you need to consider is that the large sea level rise around Tuvalu is mainly due to the increased strength of the trade winds. The trade winds bank the water up in the western Pacific. The sea level rise is localised to that part of the pacific. Water finds it's own level without the trade wind that causes a gradient of level across the pacific. To extrapolate that the rate of sea level rise over the last 60 years will continue at that rate for the next 100 to 150 years means that the trade winds would also need to dramatically increase over the next 100 to 150 years. It's simple cause and effect. It's not difficult to see that there will be a limit to the strength of the trade winds. There will be some limit as to how much the trade winds can increase by.We won't have a 24 hr/day 365 days a year hurricane for a trade wind. You need to analyse the causes before extrapolating the effect.
  50. Arctic methane outgassing on the E Siberian Shelf part 1 - the background
    I think Eric's first graph is meant to convey that there's more CH4 in the high latitudes. Since there's also more warming in the high latitudes, is the high CH4 related to this?

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