Recent Comments

Prev  1789  1790  1791  1792  1793  1794  1795  1796  1797  1798  1799  1800  1801  1802  1803  1804  Next

Comments 89801 to 89850:

89801. scaddenp at 10:55 AM on 8 April 2011
       Has sea level rise accelerated since 1880?
       A further point - how easily humans adapted in the past can be deceptive. 2000 years ago, global population was around 200 million. By time of colonisation of America, it was still less than 1 billion. Moving a few people is much easier than moving a very large no. of them dependent on complex created infrastructure.
89802. scaddenp at 10:44 AM on 8 April 2011
       Has sea level rise accelerated since 1880?
       Daniel, do think the migration of say 100 million people away from salted deltas which can no longer sustain agriculture is going happen with no problems? When in history did we have a peaceful migration of even a 1/10 of the that magnitude. You will lose the deltas to salt and erosion long before they go underwater.
89803. scaddenp at 10:36 AM on 8 April 2011
       Models are unreliable
       Ggf - there is the equivalent of wind tunnel for climate - natural forcings. Do the models predict correctly what will happen with volcano erupts, sun dims, etc. Why do you think there is so much interest in PETM? It absolute basic physics that if you increase net forcings, you will increase the temperature. If you apply heat to pot of water, its temperature will increase though you will have extreme difficulty predicting the evolving convection system. How fast it will warm is difficult but politicians have to make the choices based on best info available. That is a climate sensitivity of around 3 is consistent will model and empirical evidence. You seem to be arguing for doing nothing because we dont have perfect knowledge. Is that really sensible risk management?
89804. Bern at 10:33 AM on 8 April 2011
       Geologist Richard Alley’s ‘Operators Manual’ TV Documentary and Book… A Feast for Viewers and Readers
       For those here in Oz, here's the Booko listing. Best price seems to be $23.45 including delivery. I look forward to seeing that documentary!
89805. adelady at 09:54 AM on 8 April 2011
       Christy Crock #1: 1970s Cooling
       Yes Nick. Those of us a bit older than you were well accustomed to the idea of a nuclear winter. "If the bomb doesn't get ya, the starvation will" and similar cheery sentiments were quite common. My feeling is that this is what underlay the media's promotion of the cooling idea. We were familiar with this particular doomsday scenario and Whoops! you don't need nuclear war to get there. And we did live with dirty, to be honest filthy, skies so we could *see* how it could get worse. In Adelaide there was a huge difference driving towards the NW suburbs on a Friday evening compared to a Sunday evening. On Fridays as you emerged from the city level at the top of the slope the whole of the lower region was blanketed in brown murk. On Sundays, with industry having had 2 days off, the same trip was clear skies all the way.
89806. Ken Lambert at 09:52 AM on 8 April 2011
       A Flanner in the Works for Snow and Ice
       Sphaerica #44 You need to read and understand #43 above before you suggest that "I don't get it". The only number you have contributed to this debate is an angle of incidence of 66 degrees at the North Pole which is in error by *only* 43 degrees. Suggest that you get out your HP Calculator and find the Sine of 23.4 and 66 degrees respectively - invert them and then see the comparison of intensity of insolation. That is the size of your error.
89807. Nick Palmer at 09:27 AM on 8 April 2011
       Christy Crock #1: 1970s Cooling
       I was at school when the global cooling scare was publicised. From memory, it took advantage of our expected trend towards the next ice age in x thousand years to warn that particulate pollution, specifically soot and acid, was causing a cooling force that might set off feedbacks (more ice, more albedo) that would speed up the coming ice age. I seem to remember it all got a bit conflated with the risks of nuclear winter (nuclear war would kick up a lot of dust etc).
89808. JMurphy at 09:26 AM on 8 April 2011
       Has sea level rise accelerated since 1880?
       Not wanting to go too far off-topic, but Prometheus also lived quite high up (on Mount Olympus) and was later (painfully) confined to the Caucasus (also mostly far from the sea), so none of that conforms to the "cradle of humanity" theory also - even if it is fanciful. As for my liver...
89809. dana1981 at 09:24 AM on 8 April 2011
       Christy Crock #1: 1970s Cooling
       Albatross #12 - yes, I recall at the beginning one of the Democrats asked if the witnesses had been sworn under oath, and the chairman answered yes. To take action against Christy you'd have to prove he knew he was misleading Congress. He was very careful with his words - like I said, mainly lies by omission.
89810. Albatross at 09:13 AM on 8 April 2011
       Christy Crock #1: 1970s Cooling
       I keep forgetting to ask about this. "Christy's intellectual dishonesty while testifying before Congress under oath has misinformed our policymakers." Were the witnesses asked to swear an oath? If so, Christy's actions may be actionable-- if I understand correctly it is a felony to mislead congress.
89811. Albatross at 09:07 AM on 8 April 2011
       Christy Crock #1: 1970s Cooling
       Thanks SteveL @10, "swift boating" indeed.
89812. Daniel Bailey at 09:04 AM on 8 April 2011
       Has sea level rise accelerated since 1880?
       Aah, JMurphy stole my thunder. I shall have to start calling him Prometheus. :) Well, to salvage a comment: When the world emerged from the depths of the last ice age & the meltwater pulses flooded what humanity was then using for their civilizations at the time, there were perhaps only a few million humans worldwide. We are now pushing 7 billion persons on the globe...and struggling to feed them all. Combine the expected losses of some of the worlds most productive agricultural lands due to SLR with increasing drought and desertification, mix in societal instability and degraded & overtaxed infrastructures with hundreds of millions of climate change refugees along with nuclear-capable rogue states and you have a recipe for disaster. Those that remain will have a bit more room (a bit tough to grow crops under the harsh Arctic winter dark though), once the fighting wanes. The Yooper
89813. Albatross at 08:57 AM on 8 April 2011
       Has sea level rise accelerated since 1880?
       This is OT, but a location near Johannesburg has dibs on "cradle of human kind". And the Witwatersrand (on which Jo'burg is located) is about 1500 to 1700 m above sea level. Tamino's stats are in all likelihood correct.....the conclusions drawn from the paper in contention are based on a seriously flawed analysis and thus baseless, as are almost all 'skeptic' arguments. It is estimated that currently about 160 million people live below 1 m above sea level (Copenhagen Diagnosis). Wealthier nations may very well be able to adapt to rising sea levels, but even then building sea level defenses is incredibly expensive and an ongoing task (yet more money for maintenance). But let us not forget about those who do not have the resources for such luxuries, let us not forget Bangaldesh.
89814. JMurphy at 08:42 AM on 8 April 2011
       Has sea level rise accelerated since 1880?
       daniel maris wrote : "Humanity has always lived in "low-elevation coastal zones" - indeed many experts theorise they were a cradle of humanity. A rise in sea level won't make them disappear. All that will happen is that people will move with the sea." Cradle of humanity ? From human evolution and movement out of Africa, to the development of civilization around rivers like the Euphrates, Tigris and Nile, I'm not too sure about that. Even if true, how far inland can people move (in their millions, don't forget) as sea levels rise, and how do you think the millions already in those areas will feel about all those extra millions trying to move next to them ?
89815. muoncounter at 08:26 AM on 8 April 2011
       Has sea level rise accelerated since 1880?
       daniel maris#18: "melted ice in the Arctic for instance has no effect on sea level " Perhaps more careful reading is in order. The Arctic is sea ice; it is floating on water. By itself, that means it has minimal impact on sea level rise. However, wither Arctic ice, so goeth Greenland's land-based ice - and that's a heck of a lot of water.
89816. pbjamm at 08:22 AM on 8 April 2011
       Has sea level rise accelerated since 1880?
       daniel maris @19 "I have faith that in 11 decades' time we will have (a) have found a way of producing all our energy without adding carbon to the atmosphere and (b) found technical solutions to many of the big environmental problems." I hope so, but the first step is admitting there is a problem. Many have yet to make it even that far.
89817. daniel maris at 08:13 AM on 8 April 2011
       Has sea level rise accelerated since 1880?
       Tom Curtis - You talk of a "1 metre sea rise by 2110". Even assuming you are correct, that's 110 years off. Have you taken into account the impact of irrigation schemes? Water that used to run off into the sea is now pumped into dry desert areas and vapourises several times over - adding to the total amount of water vapour in the atmosphere. This could be offsetting sea level rise and such schemes will multiply hugely over the next 110 years. I have faith that in 11 decades' time we will have (a) have found a way of producing all our energy without adding carbon to the atmosphere and (b) found technical solutions to many of the big environmental problems.
89818. Steve L at 08:11 AM on 8 April 2011
       Christy Crock #1: 1970s Cooling
       There's a good and relevant review of some related issues (Rasool & Schneider) written by James Hansen at This link to pdf. No pictures though.
89819. daniel maris at 08:08 AM on 8 April 2011
       Has sea level rise accelerated since 1880?
       Villabolo - Are you failing to account for the fact that ice is more expansive than water? I have read that melted ice in the Arctic for instance has no effect on sea level because of that scientific fact.
89820. daniel maris at 08:05 AM on 8 April 2011
       Has sea level rise accelerated since 1880?
       JMurphy - Humanity has always lived in "low-elevation coastal zones" - indeed many experts theorise they were a cradle of humanity. A rise in sea level won't make them disappear. All that will happen is that people will move with the sea. We've seen this in reverse, where ports and other areas have silted up. We see it on our Eastern coast in the UK where people are having to move inland as the coast erodes. It's sad for the people immediately affected but it is hardly a disaster. Even with coastal erosion, where the effects are much quicker than the sort of sea level rise being talked about here, we are able to cope with minimal casualties. Sea level rise would have to be v. dramatic to make much difference to the world.
89821. Charlie A at 08:00 AM on 8 April 2011
       Has sea level rise accelerated since 1880?
       Marco, are you referring to Neil White's comment about Yukutat? White's comments not very relevant, since Houston and Dean excluded Yukutat from the analysis, along with 5 other outliers.
89822. muoncounter at 07:03 AM on 8 April 2011
       Arctic Ice March 2011
       Gilles#188: "I know that any decreasing trend can be extrapolated to zero. What does it prove ?" In this case, it is the value of your continued comments that is clearly decreasing. In the case at hand, it proves that if we continue knowingly doing the same stupid thing, we have no one to blame for the result but ourselves. More importantly, it should suggest, to someone of an open mind, that things must change before we get to zero. It should also stimulate us to work harder to rise above the incessant noise: 'no, its not,' 'I can't see the trend,' 'what is the variability on an arbitrary timescale?', 'what does it prove?' are just noise.
89823. Bob Lacatena at 06:48 AM on 8 April 2011
       Arctic Ice March 2011
       188, Gilles,

       I know that any decreasing trend can be extrapolated to zero. What does it prove ?

       The statement itself proves nothing. Your death grip on the statement and refusal to look beyond it proves that if all that you do is to look at numbers and trends and correlations, you will be frozen into inaction because you actually understand nothing. For those of us who apply science, and mechanics, and insight into what is going on behind the numbers and the trends and the correlations, it gives us a chance to alter events and so control our future. A wise man lives with a future, a fool lives with a destiny.
89824. logicman at 06:25 AM on 8 April 2011
       Arctic Ice March 2011
       Gilles: I can clearly discern the trend of your comments and they extrapolate to an infinity of 'yes buts' and a miniscularity of useful content. Our planet doesn't care what we believe. It just keeps on swinging around that jolly old sun whether or not the human race has wiped itself out. Once the Arctic is perennially ice free the unstable northern climate will do something which we cannot yet predict with any certainty. At the extremes of that range of uncertainty are two highly plausible scenarios: 1 - methane clathrates dump their cargo into the atmosphere , triggering massive global temperature rises. 2 - a warmer Arctic causes greater precipitation of snow which no longer melts entirely in summer. Within a decade or two it becomes obvious that a new ice age has started. This is not science fiction and it is not a computer game. I write about climate change because I wish the human race to continue long after I am gone. I shall pass this way but once. If I can leave behind me even the tiniest amount of scientific knowledge that is of value to future generations then I shall not have lived in vain.
89825. Nicholas Christie-Blick at 06:00 AM on 8 April 2011
       Skeptical Science in other media
       48% of Americans think that "the seriousness of global warming is generally exaggerated, up from 41% in 2009 and 31% in 1997, when Gallup first asked the question" (Gallup, March 11, 2010). 40% of Americans say that "God created human beings pretty much in their present form at one time within the last 10,000 years or so]" (Gallup, December 10-12, 2010). An additional 38% think that "Human beings have developed over millions of years from less advanced forms of life, but God guided this process. That leaves fewer than 22% of Americans whose views on evolution as a phenomenon even remotely resemble our scientific understanding. I do not think that either demographic group can be dismissed as fringe. They represent mainstream American thinking. And that is a problem.
89826. daniel maris at 05:56 AM on 8 April 2011
       A Plan for 100% Energy from Wind, Water, and Solar by 2050
       I agree with CBD. The techologies are now proven. Storage is a problem but even that is capable of resolution. Really, the problems, in so far as they exist are cost-related. And really it is an infrastructure issue. We are faced with the sorts of costs associated with putting in place a motorway network or rail network, of that order. But once in place renewables are nearly all very cheap to run - wind, solar, tidal, hydro. Storage carries a lot of cost admittedly but it is not so much as to put a renewables solution beyond our grasp. We can deploy a range of renewables solutions: hydro, compressed air, methane production, hydrogen production, chemical batteries, molten salts... Look at what Germany is doing - making rapid progress towards 20% solar (7GW installed last year). Look at Denmark - nearly at 20% wind energy. Scotland is on target to reach 50% electricity generated by renewables from 2020. I think a 100% solution within 20 years is doable if we have the political will. Perhaps we need to find in the UK something like $60billion (this is a fairly wild guesstimate on my part). $3 billion a year. It's not a huge, huge sum in terms of our GDP. It is doable I believe. Of course if we paid for the infrastructure completely out of taxation, in later years we would still be generating income from the infrastucture which would offset the investment (or - to put it another way, a large part of your elec bill already goes into funding infrastructure investment).
89827. Gilles at 05:56 AM on 8 April 2011
       Arctic Ice March 2011
       DB: I think the number of words and topics I'm adressing is much less than yours - so how to qualify your own modus operandi ? muoncounter : it may be that the Arctic will be icefree in 2030. I don't know. What I'm discussing here is the significance of a trend - and so the possibility of extrapolating it. I know that any decreasing trend can be extrapolated to zero. What does it prove ?
       Moderator Response: [Dikran Marsupial] It doesn't prove anything, but it suggests that based on the information we have, unless something changes, we are likely to see an ice free Arctic. That interpretation is so obvious, I am surprised it needs explaining to you. You do know that you can never prove an hypothesis empirically, only disprove, don't you? Also the difference between your posts and DBs is that his goal here evidently is to discuss the science, unlike you, which explains why his posts generally have useful content. Enough sniping.
89828. muoncounter at 05:28 AM on 8 April 2011
       Arctic Ice March 2011
       GIlles#186: "what is the variability at this frequency (i.e. : at a 30 years scale)" Based on the graph you posted in #158 and others (myself included) have also posted, the 'variability' is thus: Within 30 years, summer Arctic sea ice extent may be perilously close to zero. The JAXA monthly extent data show this 'variability': summer minimum has dropped by one third, from ~6 million to ~4 million sqkm, in less than a decade. It is remarkable that one who claims such powerful scientific credentials either cannot or will not see this. What can be said of a decade hence? < 2 million sq km? < 1 million? Yet you persist with nonsensical questions. 'And Nero fiddled whilst Rome burned' will be rewritten to say 'And Gilles prevaricated whilst the summer Arctic became ice free.'
89829. Dr. Jay Cadbury, phd. at 05:22 AM on 8 April 2011
       Christy Crock #1: 1970s Cooling
       Couldn't it be argued that since the last 40 million year were dominated by cooling, with the past 10,500 mostly warming, the trend has not really reversed because it would take at least that many years of warming to claim the trend has been reversed?
       Moderator Response: [DB] The majority of your comment is off-topic here. Please use the search function to find a more relevant thread if you wish to pursue getting an answer to this. If anyone wants to reply to this appropriately, please do it on the relevant thread with a pointer here. Thanks!
89830. actually thoughtful at 04:50 AM on 8 April 2011
       Christy Crock #1: 1970s Cooling
       Or, the accurate version: "There were 6 times as many papers predicting warming as there were cooling from 1965-1979."
89831. actually thoughtful at 04:49 AM on 8 April 2011
       Christy Crock #1: 1970s Cooling
       Once upon a time there was a list of one line responses to each skeptic argument on this site. For the life of me I can't find it today. I suggest the following as the one line response: "There were 9 times as many papers predicting warming as there were cooling from 1965-1979"
       Moderator Response: [DB] See http://www.skepticalscience.com/oneliners.php.
89832. Gilles at 04:41 AM on 8 April 2011
       Arctic Ice March 2011
       Mucounter :"A quick count shows at least 12 prior threads about Arctic ice loss (including Greenland, but excluding Antarctica). And yet there are still those who claim to disagree on the most basic points: Arctic summer ice extent is decreasing at an increasing rate and Arctic temperatures are increasing. " Mucounter : when I said that a variation must be estimated with respect to the noise, I'm not saying the variation does not exist. You're just stating that the variation exists, and I don't disagree on that. It was not my point. My point is : what is the variability at this frequency (i.e. : at a 30 years scale). Do we have an accurate measurement of it, yes or no ? ( - Snip - )
       Moderator Response: [DB] Off-topic portion snipped.
89833. pbjamm at 04:28 AM on 8 April 2011
       Arctic Ice March 2011
       This discussion has been interesting and educational, so thanks to all who participated. At his point though I am having difficulty following what Gilles is arguing for/against. Perhaps a restatement of your position is in order? It might clear some things up and get this discussion back on track. At the moment it seems to be all over the place and getting a bit personal.
       Moderator Response: [DB] Gilles' modus operandi, after having watched his orbit over at RC and here for over a year, is to draw as many possible people into as many conversations as they will endure for as long they can stand; in doing so, he will say less with more words than can be believed for the sole purpose of wasting your time.
89834. Albatross at 04:14 AM on 8 April 2011
       Arctic Ice March 2011
       Readers, Global warming refers to the increase in the globe's mean temperature; warming, will not be uniform across the planet, nor will it be monotonic. For example, the theory of AGW suggested for a very long time now that the northern high latitudes will warm faster than elsewhere with increasing GHG concentrations. And that is exactly what we are seeing, and not surprisingly, the ice volume is decreasing fastest in the northern high latitudes. This is all quite elementary and simple, and very well documented in the scientific literature, as are previous natural mechanisms responsible for the advance and retreat of the ice caps, yet some choose to ignore the science (and history) and choose instead to talk through their hats and troll. The trolling has now lost its entertainment value and is now boring and tiresome. This thread really needs to be cleaned up.
89835. muoncounter at 04:12 AM on 8 April 2011
       Arctic Ice March 2011
       Gilles#169: "It's a pity that we loose so much time on so simple things" For the first time, we agree! A quick count shows at least 12 prior threads about Arctic ice loss (including Greenland, but excluding Antarctica). And yet there are still those who claim to disagree on the most basic points: Arctic summer ice extent is decreasing at an increasing rate and Arctic temperatures are increasing. I suggest that anyone who claims to have 'scientific' objections must first review the mountain of data presented in these many threads; if they still have something to say other than 'I can't see the correlation' or 'No, its not,' then we can talk.
89836. Albatross at 04:04 AM on 8 April 2011
       Arctic Ice March 2011
       RE long term variability in the Arctic temperatures and sea ice, please read the links(e.g., Polyak et al.) posted in my post @38. The long term downward trend and acceleration of Arctic ice volume loss that is being witnessed in the Arctic is clearly highly unusual and not explained by natural variability alone.
89837. Gilles at 03:54 AM on 8 April 2011
       Arctic Ice March 2011
       " It is clear that ice extent began to decline around the 1850s. Prior to the 1850s the eastern coast of Greenland was virtually unapproachable due to the many miles of landfast ice extending from Nord to Kap Farvel and beyond." Very interesting, but frankly, I'm lost : didn't you say that the ice melting didn't occur before ? if there is long term (secular) variability and short term (annual) variability, what about the medium term (decadal) variability ?
       Moderator Response: [Dikran Marsupial] If you think someone has contradicted themselves, give a link to the previous comment so that it can be verified. Without it, this looks very much like trolling, the ice has waxed and waned for millenia, so it is very unlikely that any such comment was made.
89838. meh at 03:54 AM on 8 April 2011
       Call for beta testers of the latest SkS Firefox Add-on
       Unfortunately, FF4 does not think it is a compatible plugin.
       Response: Is that the "official" older version or the new beta version?
89839. Bob Lacatena at 03:50 AM on 8 April 2011
       Arctic Ice March 2011
       178, Gilles,

       It is not obvious at all for me , sorry. Do you have a correlation between summer extent as a function of winter volume ?

       I have told you repeatedly that looking for simplistic correlations and focusing on correlations without understanding physical mechanisms is a waste of time. But you know that, don't you?

       I don't see what you have explained...

       Of course you don't, because admitting to any aspect of global warming is contrary to your belief system.

       Again the first decade of the XXIth century when ice most retreated is far from being the decade when temperatures most increased.

       This is patently and demonstrably false and misleading. First, what matters here are Arctic, not global, temperatures, as I demonstrated in the graphs that you are conveniently ignoring. Second, the pace of continued warming from 2000-2010 is not nearly as important as the temperature which as been reached by that point, as well as what logicman keeps referencing, which is basically that a "tipping point" has now been reached which is freeing methods for old ice to pass out of the Arctic circle. It's basically a different paradigm than past centuries presented. Before, all that mattered was temperatures, melting the ice inward from the edges. Now, wind and water circulation patterns are becoming important, because the ice further inward has thinned and melted enough to free up. Of course, if one can't think beyond a pair of centuries long graphs, taking into account physical mechanisms and varying observations, instead of the most childishly simplistic views of things... well, you're just never going to get it.
89840. DSL at 03:50 AM on 8 April 2011
       Models are unreliable
       Ggf, I have a problem with your prediction that the warming will not exist or won't be bad. And I have a problem with your support of political action that prevents attempts to mitigate. And you must admit: your modeling is much less robust than the IPCC's. Seriously: upon what basis do you contradict not only the models (which try to tell us "how much when") but their foundational science (which tells us "what")? If you don't have a problem with the science, then you are forced to say, "It's going to happen." At that point, it would be damnable to say, "but we don't need to worry about when, because models of fluid, dynamic conditions are somewhat inaccurate." If you do have a problem with the science, then take it to the appropriate thread. Perhaps we can apply the same argument to the human climate. Politicians and governments, after all, are modelers of dynamic, fluid situations that, even worse, do not have stable structures, laws, etc. We should just give it up: no government! Oh wait . . . sigh.
89841. Marco at 03:43 AM on 8 April 2011
       Has sea level rise accelerated since 1880?
       Charlie A, please note Neil White's comment at Tamino http://tamino.wordpress.com/2011/03/31/so-what/#comment-49986. It's quite relevant to your comment (and an "ouch" for Houston & Dean).
89842. Gilles at 03:31 AM on 8 April 2011
       Arctic Ice March 2011
       sorry for unclosed boldface tag
89843. Gilles at 03:30 AM on 8 April 2011
       Arctic Ice March 2011
       concerning proxy : I didn't refer to the instrumental curve, but to the proxy reconstruction. Please read again my post "another related question : do you have a physical explanation of why the arctic sea ice extent doesn't show any significative variation in the 1900-1940 period, when the average global temperature shows a variation similar , although slightly smaller, to the current one ? and when, noticeably , proxies data show the maximal variation ? are boreal trees much more sensitive to some kind of temperatures that sea ice doesn't feel, and reciprocally? " so I think having clearly stated that 1) instrumental temperatures increased in both periods, a little bit more in the second than in the first (but not by orders of magnitudes) 2) proxies increased mostly in the first period 3) Arctic ice decreased mostly in the second one. Do you agree, or not? is there an obvious explanation for these weird correlations, showing that the temperature increase was mostly correlated with proxies but not with ice in the first period, but the opposite in the second one ? I could suggest one actually : there is a "good warming" , which is natural and can't do any harm to nature, in the first part of the century. The good warming likes trees because trees are natural, and likes polar bears too. So it doesn't make sea ice melt , but it helps trees growing. And there is a "bad warming", human-made, which does the opposite because it doesn't like Nature : makes sea ice melt and does not help tree growth Sphericae : " Please point to any one post of yours in the past year when you have demonstrated complete agreement with some aspect of current climate science." It was not the point, and I didn't claim that either. I don't see the interest to post if I have no question to solve about science. I don't ask things about relativity either. "Please point to any one post of yours in the past year when you've not taken that position on any issue." All posts : I didn't say everything was cyclical. I said that the significance of a variation must be estimated by the comparison with natural variability in a previous period. "Winter ice extent recovers close to 100%, but it is an illusion, because the ice is thin so the summer extent depends on winter volume as spring/summer temperatures, not winter extent or winter temperatures. Since the two are entirely separate, of course there's no correlation between the two. I think this is pretty obvious to everyone, so why do you bring it up?" It is not obvious at all for me , sorry. Do you have a correlation between summer extent as a function of winter volume ? "I think that pretty decisively explains why we're seeing retreating extent now and not earlier in the century," I don't see what you have explained - just drawing two curves and saying "oh they have both risen" is very far from an explanation. Again the first decade of the XXIth century when ice most retreated is far from being the decade when temperatures most increased.
       Moderator Response: Fixed broken bold tags [Dikran Marsupial] The "good warming" "bad warming" appears to be blatant trolling, I suggest this post is ignored. Also nobody here is suggesting a correlation bewteen two graphs is an explanation, it is a correllation that corroborates an explanation.
89844. logicman at 03:24 AM on 8 April 2011
       Arctic Ice March 2011
       Once again, I am grateful for all comments. The ongoing debate here has helped me to realize that I need to compile a list of all known or suspected sea-ice melt feedbacks, positive and negative. Let me correct some misunderstandings. We have maps and reports going back to the Elizabethan era which, together with many proxy studies, help us to determine the extent of ice prior to the 1950s. It is clear that ice extent began to decline around the 1850s. Prior to the 1850s the eastern coast of Greenland was virtually unapproachable due to the many miles of landfast ice extending from Nord to Kap Farvel and beyond. Baffin Bay had perennial ice which blocked access to the entrance to Nares Strait and the NWP except for 2 to 4 weeks in the year. North Baffin Bay was discovered by William Baffin in 1616 but his discovery was not believed for 2 centuries because the ice prevented any access until then. The history of discovery in the Arctic is a history of reduced total ice mass. Prior to about 1850 the Marginal Ice Zone - MIZ - would melt in summer and return in winter. Since about 1850, more ice has melted in summer on average than has reformed in winter. The discrepancy has been increasing, with a notable acceleration post 1950 and another post 1990. Contrary to popular belief the MIZ does not consist only of new ice. As new ice was advected into the main pack, to circulate and age there, older ice would advect out into the MIZ. Along the coasts of Greenland the MIZ also contains a very substantial number of icebergs. MIZ compressed into coasts continues to age. MIZ advected through Fram Strait leads to a loss of old ice. What has been changing is the total area covered by sea ice and the circulation patterns. As the main pack has shrunk and the MIZ has followed it, a point has - in my opinion - long been reached where the MIZ and the main pack were equal in extent. Judging by the 2010 and current fragmentation patterns, and the loss of multi-year ice, the main pack now has the consistency of the former MIZ. In plainer language: I fear that the Arctic's sea-ice cap is almost all MIZ - hence subject to substantial seasonal loss. Fragmented ice presents substantial open water to be heated by the sun. The warm water is advected under the ice promoting bottom melt. That bottom-melt feedback is in addition to the feedback due to the loss of albedo. I'll halt there for now, for fear that this comment might grow into an entire article. :)
89845. NewYorkJ at 03:20 AM on 8 April 2011
       Geologist Richard Alley’s ‘Operators Manual’ TV Documentary and Book… A Feast for Viewers and Readers
       what Alexandre said...
89846. dana1981 at 03:15 AM on 8 April 2011
       Christy Crock #1: 1970s Cooling
       Thanks all. By the way, the study mentioned by citizen in #1 is Peterson 2008 - the study whose data is plotted in Figure 1. Albatross #3 - Schneider mentions in his book that he's taken a lot of heat for Rasool and Schneider (1971) over the years, mainly from politicians and bloggers. Keen #5 - I have little doubt that Christy is well aware of at least most of the information in this post. The term "lying by omission" comes to mind when thinking about his testimony.
89847. arch stanton at 02:58 AM on 8 April 2011
       Geologist Richard Alley’s ‘Operators Manual’ TV Documentary and Book… A Feast for Viewers and Readers
       bibasir, I agree. I'll post a review after I read it.
89848. Charlie A at 02:57 AM on 8 April 2011
       Has sea level rise accelerated since 1880?
       The headpost by Tamino asks about Houston and Dean "Why do they repeatedly drone on about “deceleration” when the average of the acceleration rates they measure, even for their extremely limited and restricted sample, isn’t statistically significant?" The answer is given in their paper. Looking at acceleration allows one to ignore glacial isostatic adjustments, which are one of the biggest unknowns when looking at sea level. Houston and Dean looked at tide gauge levels that did not have GIA applied. This can be done since it is a reasonable assumption that the isostatic rebound adjustments do not change over the less than 100 year period they studied.
89849. KeenOn350 at 02:53 AM on 8 April 2011
       Christy Crock #1: 1970s Cooling
       Nice post - very simple - you would think Christy could understand it!
89850. Ggf9191 at 02:47 AM on 8 April 2011
       Models are unreliable
       Logicman The fluid mechanics analogy is a poor one. This is a much simpler system and the computational tasks involved here and the data collection required to produce usefull results is trivial compared to the data capture or computational difficulty in modeling global weather systems. Also the results produced by computer models can be tested in wind tunnels with clay models or prototypes to validate the results. We don't have the luxury of these things when modeling the global climate. I do not have a problem with using models to enhance or understanding of what is happening which is essentially what the fluid mechanics models are used for. But I am very concerned when countries set emmissions targets on the basis of climate models and politicians believe that achieving these targets will avert disasters that are predicted by the same models. This is suspension of disbelief on a massive scale.

Prev  1789  1790  1791  1792  1793  1794  1795  1796  1797  1798  1799  1800  1801  1802  1803  1804  Next