Arguments
Recent Comments
Prev 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 Next
Comments 122801 to 122850:
-
Ian Forrester at 14:51 PM on 7 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
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 -
HumanityRules at 13:51 PM on 7 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
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? -
chris1204 at 13:47 PM on 7 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
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. -
ubrew12 at 12:18 PM on 7 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
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. -
CBDunkerson at 10:17 AM on 7 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
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. -
Steve L at 09:52 AM on 7 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
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. -
From Peru at 08:30 AM on 7 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
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! -
Doug Bostrom at 05:32 AM on 7 March 2010What do the hacked CRU emails tell us?
Tom Dayton at 04:47 AM on 7 March, 2010 Turns out there are some problems with that evidence, including irony: 'Evan Harris, a member of the science and technology select committee, said: "Members of the Institute of Physics … may be concerned that the IOP is not as transparent as those it wishes to criticise."' More: Climate emails inquiry: Energy consultant linked to physics body's submission -
Tom Dayton at 05:25 AM on 7 March 2010Skeptical Science housekeeping: Woody Guthrie award, bug-fixes, Facebook and donations
Aha! I like that site structure, John. If we all do as you say by pointing people to the Arguments, that will reinforce that structure.Response: I've also added some explanatory text to the Link To Us page (which is where I recommend going if you're pointing someone to Skeptical Science). Thanks for making me aware of the need to explain this more clearly. -
Doug Bostrom at 05:23 AM on 7 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
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 -
Ian Forrester at 05:13 AM on 7 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
John, what are the units in Figure 2 describing the flux of methane to the atmosphere? Thanks.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."
-
Tom Dayton at 04:53 AM on 7 March 2010Skeptical Science housekeeping: Woody Guthrie award, bug-fixes, Facebook and donations
John, I hate to add to your To Do list, but it would be nice if the Arguments were linked to the Posts, preferably with short explanations of the similarities and differences. When I try to point people to the relevant places about a topic, I find myself having to point to multiple arguments and multiple posts, and being unsure about whether some of those are subsets, or are outdated versions. If an Argument is supposed to be a short version and a Post a longer version, each could point to the other, with that explanation. If an Argument or Post is out of date but you want to keep it because of existing links to it, maybe you could augment it with a bold note at the top pointing to the most recent one. Thanks again for all your hard work!Response: Okay, this is the way the website is set up. The arguments are meant to be the definitive, "encyclopedic" part of the website. So if you're pointing someone to Skeptical Science, point them to the relevant argument page.
The blog posts are in a sense documenting updates to the website. In other words, updates to the arguments section. So when a new paper is published, I do a blog post about it. I then update the relevant argument with the new info. Sometimes the argument pages get so unwieldy with all the new additions that I need to give them a complete overhaul, trimming the content to keep it readable. In those cases, I often link to the blog post with a "More info on..." link.
For example, one page that needs a bit of a birthday is Global warming stopped in 1998 which is basically just three blog posts spliced together. It doesn't make for a very coherent reading experience and I'll rewrite it one of these days.
Thanks for the comment. This is the first time I've actually articulated how the website is meant to work - until now it's only been in my head. I should put this on the About Us page or on the Link to Us page (or both). -
Tom Dayton at 04:47 AM on 7 March 2010What do the hacked CRU emails tell us?
The British Institute of Physics (IOP) has issued a statement following up its initial um... "controversial" advisory to Parliament. The initial advisory has been used by the denial blogosphere to claim that the IOP rejects the existence of anthropogenic global warming. The followup statement is intended to counter that misinterpretation. -
Tom Dayton at 04:26 AM on 7 March 2010Senator Inhofe's attempt to distract us from the scientific realities of global warming
gallopingcamel, you wrote "Lindzen & Choi 2009 suggest that the coupling is 6 times less than what the IPCC assumes." That Lindzen and Choi paper is fundamentally, thoroughly, and fatally flawed, as shown in a peer-reviewed article in press and summarized by its authors in the RealClimate post Lindzen and Choi Unraveled. If you want to argue about that, then I think that RealClimate comment thread is the appropriate place, because maybe you can get responses from the authors themselves. If you want to discuss it here at Skeptical Science, here is an appropriate thread: Climate sensitivity is low. -
Tom Dayton at 04:25 AM on 7 March 2010Senator Inhofe's attempt to distract us from the scientific realities of global warming
gallopingcamel, you wrote "Mann's Hockey Stick boils down to the idea that CO2 concentration has a strong short term effect on global temperature. This theory fails to model the past on any time scale and fails to predict current trends." That is completely incorrect, because all the hockey sticks (Mann's and the others) graph only temperature, not CO2. Relationships of those temperatures to anything else are entirely different topics, so your "This theory" does not exist. If you want to discuss the temperature hockey sticks, these threads are appropriate places: Hockey stick is broken, and Can you make a hockey stick without tree rings?. But if you want to know about and discuss theories about the multiple causes of temperature changes, including the relationship of CO2 to those graphs, here are the appropriate threads: CO2 is not the only driver of climate, and What does past climate change tell us about global warming? and Hockey sticks, "unprecedented warming," and past climate change. -
Tom Dayton at 03:36 AM on 7 March 2010Senator Inhofe's attempt to distract us from the scientific realities of global warming
gallopingcamel, you wrote "CO2 concentration correlates with global temperatures over long time scales but now we have high resolution ice core studies it appears that CO2 follows temperature by ~700 years." That topic is covered in the thread CO2 lags temperature. If you want to discuss it, that is the appropriate place. -
tobyjoyce at 02:44 AM on 7 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
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. -
tobyjoyce at 02:40 AM on 7 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
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/ -
gallopingcamel at 02:03 AM on 7 March 2010Senator Inhofe's attempt to distract us from the scientific realities of global warming
doug_bostrom (#122), Like you, I want to see a reduction in CO2 emissions. It bothers me that the two sides of the AGW debate are enjoying the war of words so much that they are not looking for things they can agree on. As John Cook is not ready to get into "solutions" yet he suggested that I contact a Barry Brook. I am pretty impressed with what he has to say about replacing coal fired power plants with nukes. The above is probably "off subject" so at the risk of irritating you I will now say something relevant to this thread: In the "intro" John Cook says that CO2 concentration in the atmosphere is rising. OK. Next he posits that man made emissions are causing the rise in CO2. Probably OK but I have some quibbles. Let it go. Then he says the extra CO2 is causing a "build up of heat". OK Then he tries to quantify the likely rise in temperature caused by CO2 and other GHGs. This is the point at which AGW theory descends into wild exaggeration and alarmism. CO2 concentration correlates with global temperatures over long time scales but now we have high resolution ice core studies it appears that CO2 follows temperature by ~700 years. Mann's Hockey Stick boils down to the idea that CO2 concentration has a strong short term effect on global temperature. This theory fails to model the past on any time scale and fails to predict current trends. When the "science" does not fit the facts it is time to ask where the theory went wrong. The simplest explanation (often the best don't you think) is that the coupling coefficient used in the GCMs is wrong. Lindzen & Choi 2009 suggest that the coupling is 6 times less than what the IPCC assumes. Even though I reject this segment of AGW theory, I still support the idea of reducing CO2 emissions for quite different reasons. First do no harm.......... -
Peter Hogarth at 01:38 AM on 7 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
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 -
Riccardo at 01:23 AM on 7 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
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. -
HumanityRules at 01:00 AM on 7 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
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. -
HumanityRules at 00:52 AM on 7 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
darn peter you beat me too it. -
HumanityRules at 00:50 AM on 7 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
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. -
Peter Hogarth at 00:22 AM on 7 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
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 -
Peter Hogarth at 00:08 AM on 7 March 2010Visual depictions of Sea Level Rise
Berényi Péter at 02:16 AM on 6 March, 2010 I appreciate the need to dig deeper into the data underneath the visualisations in this post, and then question the validity of the data in an objective way. Is the weight of independent evidence presented above enough to address your doubts about absolute accuracy of the altimeters (tracking them, as well as altimeter data)? To provide some relief from all the diverting details of satellite technology, and some historical context, I offer the following link (free) which discusses global sea level estimates and science 30 years ago - before satellites were really contributing. The latest tide station and altimeter data really is "robust" in relative and absolute terms, but it can be argued that it has refined rather than significantly revised the global 1980 conclusions (at least in this paper). http://www.ncbi.nlm.nih.gov/pmc/articles/PMC350421/pdf/pnas00499-0031.pdf Emery 1980 -
chris1204 at 23:44 PM on 6 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
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. -
Ned at 22:35 PM on 6 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
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. -
FerdiEgb at 22:25 PM on 6 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
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... -
Ned at 22:24 PM on 6 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
HumanityRules, the Solomon 2010 paper is discussed elsewhere on this site. -
HumanityRules at 22:20 PM on 6 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
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." -
chris1204 at 19:57 PM on 6 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
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? -
CBDunkerson at 18:28 PM on 6 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
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. -
Jeff Freymueller at 17:55 PM on 6 March 2010Visual depictions of Sea Level Rise
Peter, yes Jason 2 has all three. The link below includes a drawing: http://www.nasa.gov/mission_pages/ostm/spacecraft/index.html -
Jeff Freymueller at 17:52 PM on 6 March 2010Visual depictions of Sea Level Rise
#58 Peter Hogarth, I am pretty sure that Jason 2 has all three, although I would have to look it up. I don't know if every group that estimates orbits for Jason uses all of the available positioning systems, or if people use different combinations. Certainly you can use just one, and it is done to check that all are consistent with each other. The time series of positions for the ground stations that go into the ITRF definitely are produced independently. Each technique's solution is also a combination of multiple analyses. For example, the GPS time series for ITRF2005 was based on a combination of 7 separate analyses using 6 different software systems. Many of the DORIS stations are co-located with GPS, SLR, and/or VLBI stations (the general rule is that almost everything is co-located with GPS, because it is so relatively cheap). There are an increasing number of co-locations with tide stations (mostly with GPS), and the goal is to link together all of these systems. -
John Mason at 17:41 PM on 6 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
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 -
From Peru at 16:24 PM on 6 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
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? -
Andy Skuce at 15:58 PM on 6 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
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. -
Andy Skuce at 15:22 PM on 6 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
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. -
Doug Bostrom at 15:16 PM on 6 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
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." -
TOP at 15:07 PM on 6 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
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 -
James Wight at 14:33 PM on 6 March 2010Every skeptic argument ever used
Can I make a few suggestions regarding the hierarchy of arguments? When you have time, you might want to consider the following: I think “CO2 effect is saturated” more rightly belongs under “CO2 effect is weak”; and “It’s CFCs” belongs under “CO2 is not the only driver of climate”. And “CO2 is not increasing” could perhaps go somewhere in the category “Humans are too insignificant to affect global climate”. Perhaps “Pacific Islanders aren’t evacuating” could be a subcategory of “Pacific Islands are not drowning”? And shouldn’t “The Earth’s orbit is decaying” go under “It’s the Earth’s orbit”? And “Hemispheric timing” under “CO2 is coming from the ocean”? And “CO2 increases vegetation” under “CO2 is plant food”? “Technological breakthroughs will fix global warming” doesn’t seem to belong in “It’s not us” at all. Perhaps it could go instead in “It’s not bad”. Similarly, “Better to adapt than mitigate” and “China pollutes more” could both move from “It’s not bad” to “It’s too late”. “Mann inverted the Tiljander series” would seem to be the same argument as “Tiljander was flipped upside down”. The same goes for “It’s magnetic poles” and “It’s geomagnetic activity”. And “Phil Jones hid flaws in UHI study” is very similar to “Chinese station data is missing”. “CO2 limits will harm the economy” is very similar to “The benefits of reducing CO2 isn’t worth the economic pain”. Also, three particular arguments don’t seem to be displaying on the “taxonomy” list of 91 arguments: “Climategate CRU emails suggest conspiracy”, “Trenberth can’t account for the lack of warming”, and “CO2 is not a pollutant”.Response: James, thanks very much for the very detailed and useful feedback - I've actually followed all your suggestions and shuffled the arguments around to make the categorising somewhat more accurate. The argument list with its hierarchy has developed in a fairly ad hoc fashion over the years and while I try to keep it in order, well, incongruities do escape my attention. So I very much appreciate your thoughtful comments. I've also fixed the glitch that caused those 3 arguments not to appear on the taxonomy list. -
ubrew12 at 14:15 PM on 6 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
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 -
Andy Skuce at 14:11 PM on 6 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
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? -
Doug Bostrom at 13:49 PM on 6 March 2010Senator Inhofe's attempt to distract us from the scientific realities of global warming
gallopingcamel at 12:28 PM on 6 March, 2010 Indeed circumstances have changed and so has our perspective. Extraordinary claims do indeed require extraordinary evidence. However, in my humble opinion a rising tide of evidence is submerging what initially seemed to be eye-popping claims. As time has passed and I've read more on this matter I'm increasingly persuaded that C02 may represent a type of WMD that will cost us a lot whether we ignore it or not, probably more if we try to dodge accountability. Unlike the the phantom WMD of the late unpleasantness in Iraq, I don't think we'll be wasting trillions on the subsequent war; by fixing our C02 problem we'll simultaneously be getting a jump on work we need to do within the next 200 years regardless and thus making a vital and unavoidable investment while it's more easily leveraged. If I were a physicist I'd be delighted to see us finally moving from our atavistic caveman habits of setting things on fire just to derive a little heat and motive power. Instead, as a layperson who sits on his duff cashing royalty checks obtained from petroleum production, with mixed feelings, I'll still be very happy to see us stop using petroleum in a neolithic style. We should instead be husbanding petroleum for more useful things, thereby avoiding for as long as possible the need to jam hydrogen and carbon together using energy we have to obtain from elsewhere. Call me simpleminded, but this whole matter just does not seem complicated to me at all, not the physics part anyway. Human nature, different story! -
chris1204 at 13:36 PM on 6 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
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? -
Doug Bostrom at 13:32 PM on 6 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
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)
-
Jerry at 13:16 PM on 6 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
"About 11,600 years ago, the planet warmed very suddenly." How fast is suddenly? Thanks, Jerry -
Alan E at 13:08 PM on 6 March 2010Every skeptic argument ever used
Skeptical Science is the best place I know to find current information about the AGW hypothesis. Thank you to John Cook! It appears that the climate science community has no choice other than to a) publish in the best peer-reviewed journals; wait for the plethora of objections from scores of amateur scientists; and then b) respond to each objection-group with reference to peer-reviewed literature. Of course, this is happening to an extent on various sites. But I have found that such sites often revert to dismissive put-downs (eg Deltoid) or language which is inaccessible (eg RC/BraveNewClimate). The messages get lost. Trust is the critical issue. Most people (me included) don't have the time or expertise to follow and validate the micro-detailed stuff on many blogs. The questions I now use to filter material on the AGW hypothesis (pro or anti) which I trust are (order reflects weighting!): * is it from a peer-reviewed paper? * is the commentator a reviewer of climate science papers? * is the commentator an author of a peer-reviewed & published climate science paper? * is the commentator a current climate scientist who actually works with one of the climate models considered by the IPCC? * is the commentator a current climate scientist? It's the only way I can move forward ... So, this site is really important for two basic reasons - it is committed to citing peer-reviewed publications (pro and anti); and it tries to use accessible language. More please! (And the climate science community should immediately adopt the policy of making accessible ALL the source data and methods supporting peer-reviewed publications ... just make FOI requests a non-issue and remove the time demands associated with complying with FOI requests.) -
Tom W at 12:54 PM on 6 March 2010New observations find underwater Arctic Shelf is perforated and venting methane
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.
Prev 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 Next
