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Comments 89901 to 89950:

  1. Skeptical Science in other media
    nicholas. Convert? Never in a million years. What christians like John Cook and others here can do, and none of us unbelievers can do, is to show other christians that there is no conflict between science and religion. They might say they are two separate things. Or others might say that science is one way to see more of the wonder of the created world (I suspect John might be in this group). I think you're falling for the argument (of very shrill voices) that the YE creationists represent the majority christian viewpoint. They don't. Catholics, Anglicans, Episcopalians all accept the evidence of science as shown in geology, astronomy, biology, archaeology and all the rest. Lots of people who accept science hold irrational beliefs and superstitions. Astrology, feng shui, gaia belief, ancestor worship. Focus on the science. If people want to hang onto their other beliefs at the same time, let them. Getting diverted onto arguments about "you couldn't possibly believe ..... if you accept scientific method" is a waste of breath.
  2. Arctic Ice March 2011
    I note that Gilles has shown no evidence of having read the paper linked above which actually shows how to analyse for acceleration... and now we have a copy of Taminos explanation for sea level rise on site - yet he continues to shove one graph up against another and go "look, see"... 156 Gilles "But I can't prove them who I really am." No, but on discussion boards like this people tend to be judged by their deeds and words. And I echo others sentiments; I have worked with scientists, I know scientists, scientists are friend of mine. Gilles, you're no scientist.
  3. Call for beta testers of the latest SkS Firefox Add-on
    I'll be glad to test it on three configurations: FF4 under Windows XP; FF4 under Mac OS X 10.6 (Intel); TenFourFox under Mac OS X 10.5 on PPC (TenFourFox is a branch of FF4 compiled to run on PPC-based Macs).
    Response: Sounds like you've got all bases covered. File sent, thanks!
  4. Has sea level rise accelerated since 1880?
    @4. daniel maris: "...I take a rather simplistic view - I'll be interested when the water starts lapping over some islands. These effects are really very minimal. A few mms over decades?" Daniel, are you forgetting that there is a time delay before large amounts of ice completely melt for any given temperature? Also, what about the 1 degree Fahrenheit rise that is in "the pipeline" for the next 30 years? That's assuming that we stop all emissions today. Since that won't happen we have to take at least a bare minimum of 450 ppm into account (still unrealistic).
  5. Has sea level rise accelerated since 1880?
    How long does it take for sea level rise in the North Atalntic (from Greenland ice sheet melt) to spread worldwide? I recall a Newscientist article which suggested that it may take up to 30 years for a North Atlantic sea level rise to spread out worldwide. Sorry I don't have references but the author suggested that the world's oceans were analogous to a series of bathtubs linked by small hoses rather than a continuous ocean. Given that the Greenland ice sheet is likely to be a much larger contributor to sea level rise than antarctica ice sheets, this is a significant issue.
    Moderator Response: [DB] The effects of GIS melt on sea levels is indeed discussed by the New Scientist article on the Stammer JGR paper (discussed here). Effects of a collapse of the WAIS are discussed here. Keep in mind that sea level rise is continuous (globally averaging about 3 mm per year currently, but projected to rise significantly with the expected melt). Hansen 2011 discusses scenarios under which 5 meters of SLR can be expected globally by 2100, due to non-linear ice sheet decomposition.
  6. Arctic Ice March 2011
    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? on other word, could you explain the big difference in the post-1900 behavior of these two curves ? and this one ??
  7. Arctic Ice March 2011
    an answer to Tom : #152 well actually it seems that after dismissing totally the fact that we need historical records (much longer than T ) to interpret a variation over some give period T , you precisely use this method to validate the claim that you are doing - that the variation is indeed significative when compared with the past. But it was exactly what I was saying. It is not a question of fitting by any number of components, it is a question of comparing the amplitude of variation with a known noise - and to know the noise you have to measure it over a long enough period. Now it's unfortunate that the noise you're showing doesn't seem to be very accurately determined, since , "Blue shading indicates the pre-satellite era; data then is less reliable. In particular, the near-constant level extent in Autumn up to 1940 reflects lack of data rather than a real lack of variation." But there is fortunately a way of quantifying this inaccuracy : it is called "error bars" - do you have an idea of error bars associated with the pre-1940 measurements ?
  8. Arctic Ice March 2011
    I sincerely thank all people who care so much about my mental mind and can elaborate so deep thoughts about who I am, what are my real scientific capabilities , and what are my personal motivations. Unfortunately , as they don't know me personally, nor my life, or my personal opinions, they don't have the possibility to test their scientific theories by comparing them with reality. But obviously this doesn't change much their faith in their own beliefs. I'm the only one to be able to compare their judgements with my reality - and believe me or not, this is unfortunately not in favor of their perspicacity. But I can't prove them who I really am. Please notice that I wasn't claiming anything about the state of the ice in May , I was just asking for your opinion. Thanks to all who answers properly : no , there can be a lot of differences even if some parameters are equal. Well, that's what I would call a "memory", or more technically, a "hysteresis" . So let us admit there is such "memory" : my second question is : is there any clear parameter in the past (such as the value of last minimal, or maximal extent, the amount of < X years old ice, etc..) that would be useful to predict the next minimum, and allow such predictions to be made with a significative success ? (I stress again that I am not claiming anything, I just like to benefit from your deep scientific knowledge).
  9. A Plan for 100% Energy from Wind, Water, and Solar by 2050
    The problem is that almost all of that is hypothetical. That is, we lack the technology to do that now. Smart grids may exist in time. We may be able to mass produce dams. We may be able to jack up the capabilities of solar and wind. We may have hydrogen cells. Even if we do get all of those, it may not be possible to even start implementing this until 2030 or further. Unless we want to cast everything to the wind and hope we can do it, it's reasonable to suggest building new nuclear plants until then. And equally reasonable that we let them live their lives out before decommissioning them. And what will we replace them with? Well, since we're talking hypotheticals, we could replace them with pebble-bed reactors (due out 2015), Generation IV reactors (2021), or even fusion reactors, due out by 2040, a decade before we rely entirely on renewables. This WWS future simply won't materialize.
  10. Muller Misinformation #1: confusing Mike's trick with hide the decline
    "Phil Jones' email is often cited as evidence of an attempt to "hide the decline in global temperatures". This is incorrect." This is a red herring. Skeptics don't argue that at all, they understand exactly what was meant by "hide the decline" and they understand why it is problematic. Giving a flaw in the method a formal name e.g. "divergence problem" and hiding the evidence of it does not excuse Phil/Manne et al, quite the contrary. Also Muller's alledged confusion now has no bearing on events which occurred in a past decade. The author commits the same sin he accuses Muller of when he conflates these unrelated matters.
  11. Call for beta testers of the latest SkS Firefox Add-on
    Be glad to test on 3.6 & 4. also DaveW
    Response: Thanks, Dave, file sent.
  12. Daniel Bailey at 14:23 PM on 7 April 2011
    Upcoming book: Climate Change Denial by Haydn Washington and John Cook
    @ scaddenp A safe assumption. h pierce also has posted here at SkS under the name Harol Pierce Jr (probably because another user had Harold Pierce Jr). The Yooper
  13. Call for beta testers of the latest SkS Firefox Add-on
    I can test it on both 3.6.16 and 4.0
    Response: That would be great. Just sent you the file.
  14. Upcoming book: Climate Change Denial by Haydn Washington and John Cook
    I wonder if this is the same harold pierce jnr, (see the comment here) who thinks that GHE has been falsified by the temperature data in Death Valley (speaking of pie-in-the-sky nonsense).
  15. Upcoming book: Climate Change Denial by Haydn Washington and John Cook
    "Not possible. I am organic chemist and quite well aware of this info you guys mention" Ah, that explains it-no doubt you *work* for the Oil Industry, & so your mantra is nothing more than wishful thinking. The fact is that several research facilities-including MIT-have done successful pilot trials for the production of bio-fuels, from algal biomass, that is cost competitive with regular oil. That equation is only going to get better as oil prices continue to increase. "Wouldn't you really like to have a bright red Ford Mustang Conv. with a big honkin' 5 L V-8?" Personally, I'd rather have a vehicle that gets me reliably & cheaply from point A to point B-which is why I use Mass Transit on a regular basis. Still, I've always been of the view that people who use gas-guzzling muscle cars are just.....ahem, compensating for something ;-).
  16. Learning from the Climate Hearing
    johnd, I believe Professor Flannery may be the "best available" at least in part because of his high public profile. Personally, I blame the politicians for the parlous state of the climate debate in Australia. In particular, when Abbott started his ... spiel about "Great Big Tax", Rudd should have had a press conference on a bleached section of the Great Barrier Reef, and discuss the CSIRO finding that with a 2-3 degree C increase in temperature, "97% of the Great Barrier Reef is bleached every year", and that with a 3-4 degree C increase, there is "Catastrophic mortality of coral species annually", "95% decrease in distribution of Great Barrier Reef species", and "65% loss of Great Barrier Reef species in the Cairns region". Pointing out that 2 degrees C is the target of the international community, and that 4 degrees C is likely to be the minimum increase with BAU might help drive the point home. The fact is, in making their various policies, the politicians of the world are gambling that 97% of climate scientists are significantly in error. You have the Republicans (and Abbots) who are betting the scientists are almost completely wrong; and the Democrats (and Guilards) who are betting they are right about the prospects, but that they are substantially over estimating the impacts. Unfortunately the stakes they are using is our future. For Australian politicians, the most visible (but not the largest) portion of their stake is the Great Barrier Reef. Abbot is betting the survival of the Reef on Andrew Bolt knowing more about climate change than do the scientists of the CSRIO. It is not a bet I am sanguine about.
  17. Nicholas Christie-Blick at 13:00 PM on 7 April 2011
    Skeptical Science in other media
    In response to 'adelady' (comment #16): Everyone has to figure it out for him/herself. Attempting to convert people from their religious beliefs is pretty much a waste of time. It remains the case that much of what folk believe is in fact not consistent with science. And that is among the reasons it has proven difficult in the United States in particular to convey some scientific results to the general public. Climate change and evolution are the most obvious examples.
  18. Call for beta testers of the latest SkS Firefox Add-on
    Is the upgrade compatible with FireFox 4? If so I would be happy to test it
    Response: Does it work on FF4? It should do but hopefully you can tell us. I've just emailed you the file :-)
  19. Arctic Ice March 2011
    Ken Lambert @153: Answered! Relevant point for this thread: I did not just calculate incoming flux, I also referred you to Flanner who had calculated a change in forcing. In fact, I strongly suggest you use Flanner's result if you wish to make any argument about the inconsequential nature of the ice albedo feedback that is relevant to this thread.
  20. A Flanner in the Works for Snow and Ice
    Thankyou mc. Ken Lambert, the point of calculating the incoming energy was because it is easy to calculate a reasonable approximation of that figure. That reasonable approximation was sufficient to refute your argument about the inconsequential nature of reduced sea ice extent in the arctic on the arctic. On the other hand, while preferable, it is very difficult to calculate change in outgoing energy. Not only is there the change in temperature to consider (which is different for different seasons), but there is also the change in albedo/emissivity between ice and water, and the change in albedo of ice (because snow free ice has a much lower albedo than snow covered ice, and increased air temperatures often lead to snow free ice). Indeed, to be complete I would also have liked to include the change in heat carried to the ocean depths by the thermo-haline conveyor, which is also a factor. You are apparently arguing that because I did not calculate this very complicated factor (although I did refer you to Flanner, who did), I should not have mentioned the simpler but easily calculated factor of change in incoming flux. Frankly, the implied dictum that you should only present some relevant information if you can present all relevant information is nonsense. What is more, it not one you adhere to, for if you had, you would not have made an argument based solely on the minimal relevant information of relative surface area of the arctic to the globe.
  21. Learning from the Climate Hearing
    Agnostic at 11:52 AM, as is the case in almost every field, those who hold the technical expertise, are far more often than not, not sufficiently skilled to effectively articulate that knowledge to a broader audience. Thus it matters not whether the person who is appointed to undertake that role has the same qualifications or not, but rather whether he can accurately interpret and convey that knowledge to the intended audience. It is very simple, if such anointed person is deemed to effectively fulfill that role by those who appointed him, and by those whose knowledge he is presenting, then his word is as good as those he represents. If he is deemed unworthy, then he should be replaced. In the private sector, there are generally no if's and buts, either they fly majestically or are grounded. Fortunately for Professor Flannery, those who appointed him have been very clear in putting all their faith in him being the best available, something that I expect many see as a fact.
  22. Has sea level rise accelerated since 1880?
    daniel maris @4, while I agree that the prospective sea level rises over the coming century could be handled very comfortably by advanced economies, I believe you are being far to sanguine. During the Eemian epoch, the last interglacial, the mean global surface temperature was 1 to 2 degrees warmer than the those in the middle of the 20th century, ie, 0.3 to 1.3 degrees warmer than today, and around the temperature target currently muted for stabilizing CO2. During the Eemian, the sea level was 4 to 6 meters higher than at present - sufficiently high to turn Scandinavia into an island. So that is the sea level, at minimum, we are heading for given sufficient time. Of course, glacial melt, the primary source of the sea level rise, is slow. Assuming it rises to the average rate during the last great glacial melt, ie, the end of the last glaciation, then sea levels will eventually be rising at about 15 mm per year, or 1.5 meters per century. It will take a while to ramp up to that, so lets predict about a 1 meter sea rise by 2110. I believe that to be a reasonable estimate. Three things should be noted about that: 1) Even with a 1 meter sea rise, the costs of responding to that, either by building sea walls, or by abandoning properties and shifting to new locations, will be less than the cost of eliminating fossil fuel use from our economies. So if that were the only cost of global warming, perhaps we would be better with BAU. But it is not the only cost - indeed it is probably the smallest prospective cost of global warming, so BAU is not a sensible strategy. 2) That rate of sea level rise would not stop in 2110, but in fact continue of for another two or three centuries after that. Just factoring in the short term costs is poor planning, particularly when the long term costs will involve either placing a 10 meter plus sea wall around most of the coast line of most nations, or the loss of very significant areas of arable land. 3) This grim if very slow impact is more or less what we are committed to already. If we go to zero carbon economies by 2050, we are already looking at 4 to 6 meter long term sea level rises. If we continue at BAU, the rise is likely to be much larger. Finally, none of this should detract from muoncounter's very excellent response. Although responding to sea level rise is very doable, it involves large scale capital works and/or land resumptions. In other words, it is an expensive project whose benefits will not be fully felt until 20 to 30 years after the event. Governments don't do that sort of project well, so we are likely to experience the cost of sea level rise in increased damage and financial costs from storms. And if we do it that way, the costs will be significantly greater than the costs of eliminating fossil fuel use from our economies.
  23. Learning from the Climate Hearing
    My comment refers to climate scientists. Professor Flannery though very well informed is not a climate scientist, and his recent appointment has yet to demonstrate any success in public education, let alone education of those who govern us. Like you, I wish him every success in his February, 2011 appointment as Climate Commissioner. What I am critical of is the role of climate scientists over the past 3-5 years in providing information to our politicians – and of politicians for not seeking such advice and the gullibility of those who accept the views of the likes of Plimer in preference to the findings of climate science.
  24. Climate myths at the U.S. House Hearing on climate change
    @RSVP. Just shows how little you know. Fossil fuels were *massively* expensive back in the 19th & early 20th century, & were only made affordable by a massive injection of capital from both the public & private sectors. Even so, it still took close to a century for the price of fossil fuel energy to reach the levels we enjoy today. Yet suggest a similar approach to renewable energy, & the politicians & their rich puppeteers tell us that renewable energy should have to compete in an "open market place", all whilst nuclear & fossil fuels *continue* to enjoy substantial subsidies from the tax payer. So *no* I don't accept that science is to blame-its the politicians & the fossil fuel lobby who're doing there level best to prevent renewable energy from being cost-competitive.
  25. CO2 lags temperature
    Agnostic, I gather you contesting whether carbon feedbacks are slow, not they will make warming worse. While I dont doubt Shakhova et al, results, what we dont have is an idea as what is "normal". This was discussed at Realclimate last year.
  26. Has sea level rise accelerated since 1880?
    Daniel, you are joking? How about issues we face now? Salt contamination of farmland on deltas; roadways, farms and houses under threat from coastal erosion - hell, my city is dithering on whether to fight or retreat for large hunk of it in the long term. Salt is already a problem and the dune barrier takes a hammering in high seas. Problems start LONG before things go underwater. If we get 10mm/yr, that's catastrophic. Lets just not.
  27. daniel maris at 11:18 AM on 7 April 2011
    A Plan for 100% Energy from Wind, Water, and Solar by 2050
    One future development that will be of particular help is infrared energy collectors. Idaho National Lab is working on micro-atennae that will pick up infrared energy leaving the ground at night and convert it into electricity. These could be placed on the underside of photovoltaic panels. This will give a 24 hour power source. Thanks for the critique of the wind scare story Mike - I didn't think it sounded v. credible.
  28. Learning from the Climate Hearing
    Agnostic at 10:39 AM, you seemed to have seriously overlooked the efforts of Professor Tim Flannery who has been given the responsibility by the Labor government to address such matters. Promoted as being one of, if not the foremost climate change authorities in Australia, and with the resultant high profile bestowed upon him, surely the results of his considerable efforts are becoming evident, or do you disagree? Is there anyone more able then Tim Flannery to convey the reality?
  29. CO2 lags temperature
    Scaddenp (303) … “Carbon-cycle feedbacks are slow. Most AR4 models ignored them as irrelevant for next 100 years. If this is incorrect, then warming would be worse.” I thought Sharkhova et al (2010) had rather clearly shown this to be incorrect. Warming will be worse as will Arctic amplification and its effects on the GIS.
  30. Has sea level rise accelerated since 1880?
    daniel maris#4: "I'll be interested when the water starts lapping over some islands. These effects are really very minimal." Fast forward 30-50 years; suppose mean sea level is up approx 0.75 meters from today. Go to a place that is actively subsiding such as anywhere on the coast of South Louisiana. Add in a hurricane with even a modest storm surge. Not quite so minimal anymore. Now put that event at Port Fourchon, La (mean elevation 0); its the terminal for the Lousiana Offshore Oil Port (which handles 15% of US annual imports). It also services 90% of the deepwater rigs and half of the shallow water rigs in the Gulf of Mexico. From a 2008 impact study: We conservatively estimate that a three-week loss in services from Port Fourchon would lead to: • A loss of $9,994.7 million in sales at U.S. firms; • A loss of $2,890.9 million in household earnings in the U.S., and; • A loss of 77,440 jobs in the nation. The longer it takes to restore activity at the port or the longer it takes to shift services to other ports along the coast, the greater these losses will be. Definitely not so minimal any more. And even if we have 'cracked' carbon reduction by then, that won't halt sea level rise for a long while. Any relation to Roger Maris of NY Yankees fame?
  31. Learning from the Climate Hearing
    Though less publicised, many Australian Members of Parliament have been smitten with the pseudo-skeptic disease exhibited by far too many members of Congress. The National Party simply denies that climate change is occurring. As far as they are concerned natural variability explains it all – but if farmers can earn additional income from government mitigation schemes, more power to them. Members of the Liberal Party (under present leadership, converted to right wing conservatism) hold a variety of views. A few accept the science and need for action but remain silent rather than show the Party is split on the issue. Most seem to somewhere between the few recognising the science and those typified by Senator Minchin who not so long ago, while still Senate Opposition Leader described AGW as a left-wing international conspiracy for world domination and an ‘abomination’ to be rejected by all. This sad state of affairs is, at least in part, the fault of climate scientists, the august bodies to which they belong and the Australian government led by a self-declared “true believer”. None have done enough (or anything) to have leading climate scientists present Members of Parliament and their staff, including Party Officials, with evidence supporting the reality which is AGW – or the effects it will have on Australia. This neglect applies to Federal, State and Local Government. If climate scientists do not provide information to those who govern us, they should not be surprised at the negative attitude they display. There is obvious truth in what Gerda (11) has to say on the subject but on the other hand, unless politicians are personally presented with evidence of cause and effect, do not expect them to act responsibly, either here or in the USA.
  32. Has sea level rise accelerated since 1880?
    'It looks to me like it could just as easily have a downward line drawn through it with no significance.' Then why dont you run the regression test and show us? What mathematical method do you propose will give you a downward line? As to past sealevel rise. The questions are: 1/ Why did is rise in the past and do those reasons apply now? 2/ What was the RATE of sealevel rise globally over last 5000 years? (hint very, very small). Also individual tide guages are subject to local tectonics. Do really believe your anecdotes about sydney and Scandinavia constitute a scientific statement about global sealevel rise? Especially compared to the proper methodology of Church and White?
  33. Arctic Ice March 2011
    The trouble with arguing with Gilles is that he isnt interested in truth, only in winning an argument (or perhaps winning one). I bet he was tops in high school debating. You have to watch for the disingenuous debating trick all the time. Do you really think Gilles is unaware that ice volume is decreasing?
  34. Upcoming book: Climate Change Denial by Haydn Washington and John Cook
    "Wouldn't you really like to have a bright red Ford Mustang Conv. with a big honkin' 5 L V-8?" Sounds like "skepticism" driven by wishful thinking. Its not what we would like, but we can have. I have yet to see anything from you which shows "pie in the sky nonsense". That is unsubstantiated assertion at best.
  35. daniel maris at 10:03 AM on 7 April 2011
    Has sea level rise accelerated since 1880?
    I take a rather simplistic view - I'll be interested when the water starts lapping over some islands. These effects are really very minimal. A few mms over decades? I mean - put a bit more cement on top of your sea wall...abandon that pontoon and build a new one...move your settlement a few feet up the hillside. These are not cataclysmic effects - no more cataclysmic than say a port getting silted up. We will have cracked carbon reduction long before these sorts of figures give us serious cause for concern.
  36. Arctic Ice March 2011
    Tom Curtis #128 Tom Curtis has not responded at the Flanner thread so here is my point which took us there: Tom Curtis #40 says: **"I should first note that I originally identified the figure I calculated as the change in incoming flux only. I said, "Of course, not all the ice is melted because much of the energy escapes to space rather than being used to melt ice." (emphasis added) In a following post I said, " I am going to conclude that the "discreprancy" is simply a consequence of your mistaking different figures as representing the same estimate."** What is your point in calculating the incoming and ignoring the outgoing? Surely the whole discussion of AGW is about the *net* warming effects. One might as well suggest that we only look at possible changes incoming flux on *any* part of the Earth, while ignoring the changes in outgoing flux. A 0.75 degC increase in the surface temperature which is reflected in a similar emitting temperature will increase S-B outgoing radiation in proportion to (T1/T2)^4. That is the major cooling response. This applies equally to the Arctic as a 'black body' as anywhere else.
  37. Climate myths at the U.S. House Hearing on climate change
    Thanks Dana. I look forward to seeing it. But I couldn't wait and I looked up Rasool and Schneider -- darn it, that's a paper that contradicts my premise! Their projections ARE based on aerosol amounts. Now I'm curious about the others.... But I still look forward to your summary of Rasool and Schneider. Cheers.
  38. Has sea level rise accelerated since 1880?
    Sea level has been rising for the past 20,000 years. In some parts of the world (eg Scandinavia)it's been dropping. Here in Sydney it's increased about 8mm over 25 years, though nothing much in the last decade. Looking at the curve fit in the last graph, which is claimed as significant, I couldn't help laughing. What is the level of significance? It looks to me like it could just as easily have a downward line drawn through it with no significance. Looking at the charts around the world, I find it hard to really see acceleration in recent times.
  39. Upcoming book: Climate Change Denial by Haydn Washington and John Cook
    pierce#36: Still off-topic. Fossil fuels are, by definition, not forever. How will that 5L V8 do with $5 a gallon gas? Sure make a good-looking lawn ornament. Once again, the 100% renewables thread, with its self-proclaimed resident expert on the end of the fossil fuel era, is a better place for these comments.
  40. Arctic Ice March 2011
    For the casual reader, Gilles has been trying to muddy the waters with a series of intersecting arguments. In logical order they are: A) The record of ice extent is too short to determine if the apparent trend is an actual trend or part of a larger cycle. Response: Epistemologically, this is an absurd argument. It is a truism of mathematics (and philosophy, where it is called the problem of induction) that any series can be generated by an infinite number of mathematical formulas which depart arbitrarily after a given point. Therefore, no length of recorded data is long enough to guarantee that the sequence is a declining trend rather than, for example, a cycle, or even just random noise. The epistemological solution, all else being equal, to use the simplest hypothesis, which will always have an a priori higher probability than the more complicated hypotheses. Mathematically, a declining trend is simpler than a cycle. Of course, in this case, all else is not equal, and there are good physical reasons to expect a declining trend rather than a cycle. We can illustrate this by considering a longer data series than the satellite arctic sea ice extent. The classic example would be the instrumental temperature record, which it is argued, by deniers is just the result of a 1500 year cycle (and never mind the inconsistency that the last peak in that cycle was just 500 years ago). I instead will use the historical arctic sea ice extent data:
    Sea ice extent in million square kilometers. Blue shading indicates the pre-satellite era; data then is less reliable. In particular, the near-constant level extent in Autumn up to 1940 reflects lack of data rather than a real lack of variation. Extends File:Seaice-1870-2007.png to 2009 using data from ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/
    Let us put aside the small detail that this data completely rebuts Giles contention that the thirty year decline in sea ice on the satellite record may just be part of a 60 year cycle. After all, he can (and probably will) with equal validity argue that the historical data is just part of a four hundred year cycle, which just coincidentally shows a decline just as global temperatures rise sharply as a result of GHG forcing. Which is the point, really. No amount of data can prevent somebody seriously intent on obfustication from running Giles' argument. Sensible people make up their minds on the data we have - not on what might have been the data in some hypothetical nether world as Giles would have you do. B) The sea ice has "no memory" of any ice albedo fluctuations to drive further melting. Therefore, each winter resets the initial conditions preventing a feedback driven ice melt from creating any long term trend. Response: This is a shell and pea game. Gilles want to keep your eyes carefully watching the shells (sea ice extent) so that you don't notice the pea (sea ice volume) being slipped into his hand. Sea ice volume is particularly important in this context. Studies have shown that increased heat absorption due to exposed ocean surface has a far more direct effect on sea ice volume than on sea ice extent:
    Fig. 3. Solar heat input and melting. Comparison of (a) heat used in surface melting, Qms, to solar heat input to ice, Qi, during the period of surface melting and (b) heat used in bottom melting, Qmb, to solar heat deposited in open water, Qw. The straight lines are the linear leastsquares best fit to the data. In (a) the slope is 0.42, with a correlation coefficient of 0.38. In (b) the slope is 0.89, with a correlation coefficient of 0.94.
    This is not surprising. Direct radiation to the surface of the ocean warms the water, which then warms the ice by conduction. But the ice has far more contact with the water on its underside than on its edge. Further, a 100 meter melt on the edge of the ice cap will make a far smaller difference to extent than a 1 meter melt to the underside of the ice will make to volume. The consequence is that the ice albedo feedback has a far more significant direct impact on ice volume than on ice extent: Reduced sea ice volume in Spring aids the rapid reduction on sea ice extent by September both by making it easier (requiring less heat) to melt back the edges of the ice flows, and also by enabling a greater break up of the ice, by exposing more edges to the (relatively) warm water.
  41. Peter Hogarth at 08:56 AM on 7 April 2011
    Has sea level rise accelerated since 1880?
    The GIA corrected altimeter trend is 3.2 +/- 0.4 mm/yr and the GIA corrected tide gauge data trend is 2.8 +/- 0.8mm/yr over the same altimetry period since 1993. The new Church and White 2011 paper is available. It also has a clearer chart than mine! (figure 4) Another assumption made in the Houston and Dean paper is that GIA uplift rates for the Northern US coast are stable, whereas there is some evidence of accelerating uplift in the North Atlantic as a result of increasing Ice loss, see for example Jiang 2010 . Any small regional acceleration in uplift would reduce effective tide gauge recorded rate of msl increase.
  42. Upcoming book: Climate Change Denial by Haydn Washington and John Cook
    Marcus at 35 So, Pierce, it seems you need to go back & do your homework before you further embarrass yourself. Not possible. I am organic chemist and quite well aware of this info you guys mention here most of which is pie-in-the sky nonsense! I stand by "Fossil Fuels are Forever"! Wouldn't you really like to have a bright red Ford Mustang Conv. with a big honkin' 5 L V-8? Go which watch "Mighty Ships" on the History Channel.
  43. Arctic Ice March 2011
    Yet more that the so-called skeptics can obfuscate about : Icy Meltwater Pooling in Arctic Ocean: a Wild Card in Climate Change Scenarios Freshwater is twice the volume of Lake Victoria and growing; Scientists inventory, synthesize 13 years of research on climate change and Europe’s marine environment A massive, growing pool of icy meltwater in the Arctic Ocean is a wild card in future climate scenarios, European researchers said today. Estimated in 2009 at 7,500 cubic km – twice the volume of Africa's Lake Victoria – and growing, the water could flush quickly into the Atlantic with unpredictable effect when prevailing atmospheric patterns shift, as occurred most recently in the 1960s and 1990s.
  44. Peter Hogarth at 07:58 AM on 7 April 2011
    Has sea level rise accelerated since 1880?
    Thanks Tamino. Worth adding that this latest Church and White data set (with tide gauge data updated to 2010) shows a trend that is close to the altimeter record trend over the entire altimeter period. This should reduce any doubts raised in the paper about the altimetry record. Both records are significantly higher than the 20th century average of around 1.8mm/yr, indicating a recent increase in trend.
  45. Arctic Ice March 2011
    Gilles: A graph of this type is just one way of recording the variations in ice extent, area or volume over a period of time. The advantage of the overlay method is that it helps to compare year with year as to quantity of ice and rate of melt/growth at specific times. Here, I have taken the graph of 2010 ice behavior and used it as a projection of 2011 behavior. If, and only if, ice behavior this year is exactly the same as last year, then the projection shows what we may expect to see in the coming months. In fact, 2010 was anomalous in that ice losses stalled somewhat about June. Had 2010 been a more 'normal' year, ice losses would have been greater. I therefore regard this projection as somewhat conservative.
  46. Skeptical Science in other media
    ptbrown31: "I also think that it is unwise to go down this road of trying to mix science and religion. I feel that they are very much incompatible by their very definitions. Science as a practice tries to remove 'faith' in ideas at every turn, instead emphasizing empirical evidence. Religion, on the other hand glorifies belief in things for which there is little evidence." There's no need to mix science and religion, but on the other hand there's every need for religious people (like myself, though like many Christians I don't feel religious per se; I just happen to know who I am!) to know science. There can be no harm in using the platform of SkS, started by John because his faith motivated him to do it, to teach scientific scepticism to the masses. If there are some people who are anti-climate change science because fellow believers had proved convincing (to them), maybe having a fellow believer with an alternative viewpoint would sway them. "I find it very odd that in Katharine Hayhoe's interview she seems to be arguing that you don't need to accept that the earth is older than 6,000 years old to believe in climate change. Why would someone accept any of the scientific arguments for AGW theory if they are unable to accept such a basic scientific principle? If you don't care about evidence you don't care about evidence." Who knows? Though evidently Katherine knows that her audience will contain YECs, so why not chuck in that it's no reason to reject more science. While we're at it, have a religion/science joke: The Higgs boson walks into a church. The priest says "Your kind isn't welcome here." To which the Higgs boson replies, "But without me, you can't have mass!" Badum and, indeed, tish.
    Moderator Response: [DB] A quality joke deserves a quality Rimshot...but we'll have to settle for this. :)
  47. Skeptical Science in other media
    Considering the response of others to the faith/science incompatibility debate, I'm wondering why my comment was censored. It appeared originally as post #8, but it has now disappeared. I think there should at least be an indication that a post has been censored and a reason given for why it was censored. In any case, I would like to add my voice to the case for science. This blog is called Skeptical SCIENCE. I think we can do without the vicarious proselytising.
    Moderator Response: Profanity. Sorry, but standards are tight here.
  48. daniel maris at 06:21 AM on 7 April 2011
    A Plan for 100% Renewable Energy by 2050
    I agree with Muoncounter... There are clearly loads more hydrocarbons available on the planet. Price might go up, but that just makes exploration and extraction more attractive. But if the trends continue for the next 20 years we will see renewables become cheaper than hydrocarbons. Onshore wind is already cheaper than nuclear. Once renewables are fully price competitive, they will quickly come to dominate electricity generation. In terms of economic growth, there is no reason why we shouldn't continue to enjoy huge increases in per capita wealth once we get population on a reducing trend. Within the next 100 years, the likelihood also is that we will see a growth in the space economy providing effectively limitless raw materials and energy (solar energy will be beamed to earth by microwave beam).
  49. daniel maris at 06:00 AM on 7 April 2011
    A Plan for 100% Renewable Energy by 2050
    Perseus - What's your evidence that "several weeks or months" of storage would be required under a renewables policy during winter anticyclonic conditions? I very much doubt that such an extended storage period would be required. I think what you would need is a combination of the following: 1. A continental grid. 2. Compressed air storage. 3. Hydro storage. 4. Methane/hydrogen storage. 5. Ramping up biofuel production during these periods. 6. Ramping up energy from waste production during these periods. 7. Giving tarrif discounts to organisations that agree to reduce energy usage during these periods. 8. Keeping a reserve gas facility for emergencies.
  50. Arctic Ice March 2011
    Gilles wrote : "Note how all curves intersect in a somewhat messy way around 15th of May." I would suggest that they are somewhat messy and intersect-y around mid May to mid June, i.e. half-way between maximum and minimum. Spooky, eh ? What can it mean ? Perhaps, with your self-confirmed scientific training, you can reveal what it is you might have discovered there ? Bound to be something important, that no-one else has noticed before.

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