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Comments 123451 to 123500:

123451. dhogaza at 13:05 PM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        Uh, HumanityRules, the lawyer in question got corrected in the comments. That's not quite the same as suggesting that his blog post isn't arguing that sea levels won't rise. His only post in the comments section suggests he didn't quite understand the implication the first time his error was pointed out (he suggests it means that the *lowest* estimate can't be established, and says nothing about the upper). And least he did try to understand the correction. I'll give him points for: 1. Letting posts through showing his interpretation was wrong. 2. Not showing the kind of stubborn attachment to a misinterpretation that a Certain Someone on this blog is showing. 3. Being such an unknown blog that the corrections weren't immediately screamed down by a horde of the typical denialist trash. We'll see whether he'll state something showing he actually understands the full depth of his misunderstanding .
123452. HumanityRules at 12:57 PM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        I'm not sure that the blog you linked to is really arguing that sea levels won't rise. The title and first line maybe a little tongue in cheek but generally they are reporting the facts of the situation. Similarly a more (dis)respected skeptic blog WUWT reported this mentioning the Vermeer and Rahmstorf estimates as you do. Seems like you are setting up a paper house to knock down.
        Response: Some will report it accurately, others lead with headlines like 'Now You Can Forget About Those Rising Seas'. I'm in the unfortunate position of having to respond to the lowest common denominator.
123453. dhogaza at 12:24 PM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        Berényi Péter, your chance of regaining credibility here would probably go up a bit if you acknowledged your interpretation of Siddal's comment about "overestimating the sea level response" was incorrect. I didn't go to all the trouble of making that post just to see you ignore it.
123454. chris1204 at 12:09 PM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        David: 'Hard to see any winners this time around.' As a highly technological society, we are vastly more adaptable then hunter-gatherer societies. Moreover, extinctions are neither good nor bad - were there no extinctions, there would be no evolution. Extinctions (like the poor) will always be with us. So too with change. Not that we want to accelerate extinctions (or increasse poverty) if that can be avoided. The real issue relates to the priorities we set for our resources. If we try to do this as rationally as our limited knowledge permits and avoid emotive value judgments, we are likely to emerge with better outcomes.
123455. kwinters79 at 12:04 PM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        Berényi Péter (22) wrote: "Fitted least squares parabola to data (960121.rlrdata), coefficient of x^2 negative. " That's quite odd, because when I do that I get a positive coefficient for x^2. 0.0023, if I use the interval from 1883 - 2008 (skipping the 1878 - 1893 gap) or 0.0036 over the entire 1856 - 2008 period. But the acceleration becomes even more obvious when you plot a series of 30-year linear trend lines. 1900 - 1929 slope = 1.6723 1940 - 1969 slope = 2.8465 1976 - 2008 slope = 3.983
123456. SLRTX at 11:36 AM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        Based on some back/forth I'm seeing in these posts, I see a fallacy that the so-called "skeptics" use. They mis-apply the "appeal to authority" fallacy - which in itself is a fallacy. First, any reasonable person knows no one person can possibly know the minutiae of every detail about climate change. Like any scientific discipline, it's a collective (peer-reviewed) process. Second, because of the first point, we MUST, at some point, defer to other experts. The so-called "skeptics" then claim this is the "appeal to the authority" fallacy. Not. So. Fast. If that were true, we'd all be guilty of that, each time we visit the family Dr. After all, we don't know all there is to know about medicine, but we do "appeal to the authority" when it comes to medical advice. Here's a link that explains that at times it is reasonable to appeal to the RIGHT authority. http://www.nizkor.org/features/fallacies/appeal-to-authority.html So for me, I am perfectly happy deferring to the collective knowledge of the climate scientist, as much as I am happy to take the advice of my family Dr. :-) As I said in my earlier post - being a bit off on the predictions about the timing of the effects of climate change, does not change the fact that ACC is indeed happening. There are, and will be, consequences.
123457. Berényi Péter at 11:22 AM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        #24 Albatross at 10:58 AM on 25 February, 2010 "there is not a diconnect between science and "logic and truth" as you suggest" Right. This is the way it is supposed to be. Unfortunately ideals are not always met. #25 JMurphy at 10:59 AM on 25 February, 2010 "observed local sea level trends may differ greatly from the average rate of global sea level rise, and vary widely from one location to the next" Of course. But right now we are not talking about speed of rise/sinking but acceleration.
123458. David Horton at 11:21 AM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        "It's also a flooded river valley carved out aeons ago before a massive sea level rise. One river valley lost - one beautiful harbour gained." just a tiny missed point here Chris. The period from the river valley to the flooded harbour was long, and the people being affected by it had a highly mobile small population, no permanent infrastructure, and a hunter-gatherer economy that was just as happy fishing in a harbour as hunting in a valley. None of that applies to 21st century Australia or indeed any other modern country. And by way of warning - the last time Australia's climate switched from cool and wet to hot and dry (essentially the modern climate although a bit drier), dozens of large animal species went extinct, unable to deal with vegetation zones shifting outwards over a period of a few thousand years. If this scenario is repeated over a time span of a hundred years or less there are going to be massive extinctions of flora and fauna, and the agricultural communities of regional areas. The only "winners" at the end of the Pleistocene were a few desert species like red kangaroos. Hard to see any winners this time around. Certainly no human winners.
123459. Berényi Péter at 11:09 AM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        #21 Jeff Freymueller at 10:48 AM on 25 February, 2010: "Whether or not you can detect an acceleration in a single tide gauge record is really beside the point" No acceleration upward at Stockholm, Sweden either. I could download the entire PSMSL dataset and compute acceleration for each tide gauge, but I can't believe it is not done already. Any pointer? However, acceleration of even a single tide gauge (or the lack thereof) is remarkable, provided the record is reliable and there is no vigorous tectonic activity in the region. As satellite measured recent sea level rise is faster than estimated 20th century average, it is often cited as proof of acceleration. However, satellites need calibration, must be faulty if no acceleration is detected at ground level.
123460. Ned at 11:06 AM on 25 February 2010
        Have American Thinker disproven global warming?
        I just want to say that this thread has helped me understand some things that I not only didn't understand before but didn't realize that I didn't understand. Thanks!
123461. chris1204 at 11:04 AM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        John Russell: Was it Ghandi who said, "first you'll be ignored; then you'll be laughed at; then they'll fight you; and finally you'll win"? Gather strength everyone; it's always darkest just before the dawn. I don't know what Ghandi actually said. However, he was a politician with an idealistic vision, not a scientist. I live near Port Jackson (aka Sydney Harbour) - one of the most beautiful harbours in the world. It's also a flooded river valley carved out aeons ago before a massive sea level rise. One river valley lost - one beautiful harbour gained. Climate change brings winners and losers like any process in nature. It's helpful to discern likely outcomes - we can try to modify them or adapt to them. However, we have to learn to accept the uncertainties inherent in scientific discourse about highly complex systems and perhaps our own limitations in the face of processes incorporating variables as yet unknown to us. This requires humility - a quality sadly lacking in many advocates on both sides of the climate change divide.
123462. JMurphy at 10:59 AM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        Berényi Péter, please see : http://www.epa.gov/climatechange/science/recentslc.html "In the United States: Sea level has been rising 0.08-0.12 inches per year (2.0-3.0 mm per year) along most of the U.S. Atlantic and Gulf coasts. The rate of sea level rise varies from about 0.36 inches per year (10 mm per year) along the Louisiana Coast (due to land sinking), to a drop of a few inches per decade in parts of Alaska (because land is rising)." Also : http://tidesandcurrents.noaa.gov/sltrends/faq.shtml "Depending on the rates of vertical land motion relative to changes in sea level, observed local sea level trends may differ greatly from the average rate of global sea level rise, and vary widely from one location to the next."
123463. Albatross at 10:58 AM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        Berényi Péter @14 "I care neither for reviewers nor the scientific community, but I do care for logic & truth." That statement is not consistent with you posting here in a science forum. Also, there is not a diconnect between science and "logic and truth" as you suggest. Whether you like it or not, the research in question has been undertaken and reviewed by scientists who are experts in the field. You should care what they have to say b/c they have invested infinitely more thought and effort on this problem than anyone us here. "Appealing to authority is NOT the way science is done. Not even scientific authority is competent in this respect. As long as you are able to understand stuff, you are self sufficient." I'm not appealing to authority, and I am very familiar with how science is done. There is nothing wrong with acceptingand acknowledging that soneone is an expert whether they be a cosmologist, oncologist or climate scientist. I do not know to which "scientific authority" you are referring. As for understanding stuff, dhogaza and others have explained to you why you do not understand as much about this complex problem as you might think. And that is not a slight, we here are all in pretty much the same position in terms of level of understanding and, for reasons stated earlier in this post, we should be very cautious about being cavalier or simply dismissing the science. Science is, whether you like it or not, remarkably good at self correcting. It also advances if someone, like you who is critical of the methods and analysis, is willing to invest the time and effort to improve upon previous work and address the perceived weaknesses, rather than simply poking holes in someone elses work. I, for one, don't care what your credentials are, so long as you can undertake solid research which survives the rigour of peer-review and subsequent critique by the collective expertise in the field, then you have advanced the science. Like it or not, the science is converging towards the higher end of the expected range of increase in SLR. A recent study by SCAR projected that sea level will increase by as much as 1.4 m by 2100-- and SLR will not magically stop rising in 2100. Just as an oncologist is not paid to ignore unfortunate diagnosis and plausible outcomes/prospects for recovery (or not), nor are scientists paid to avoid telling us about the threat of potentially serious scenarios. That is not being "alarmist" is is being prudent and responsible.
123464. Ned at 10:57 AM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        Berényi Péter writes: I am prone to err as anyone, correction is welcome. However, in this topic I have not seen a valid one yet. You must have missed dhogaza's comment here, which did a nice job of correcting your misunderstanding about the meaning of the expression "an overestimation of the sea-level response". What was overestimated was not the rate of rise, but the time scale of the leveling off in rise once available land ice has nearly all melted. That's something that won't happen until nearly all the ice is gone, so the implication of this is clearly that Siddall's paper underestimated 21st century SLR.
123465. Berényi Péter at 10:49 AM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        #21 shdwsnlite at 10:41 AM on 25 February, 2010: "What was the process?" Fitted least squares parabola to data (960121.rlrdata), coefficient of x^2 negative.
123466. Jeff Freymueller at 10:48 AM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        #18 Berényi Péter, their model sea level includes a response time in the differential equation that they solve. This deals with the fact that the response to a step increase in temperature would not be a step increase in sea level, but instead sea level would start to rise for a while, then level off after some time. It looks to me like they estimated this constant based on the fit to the last 22,000 years of post-LGM sea level rise (the details are in the supplementary material, not the main paper). This means that if there was no change in temperature starting in 1900, for example, you would still expect sea level to rise for a while because of past temperature changes, but the rate of rise would go down with time. So the 'new rise' is the response to the temperature changes of the 20th century. I find Rahmstorf's approach easier to understand, but the way, and it is probably more useful to discuss that approach. (Another time, at least for me, I need to log off here and get some work done). As for acceleration of sea level rise, you can see from Figure 3 of Vermeer and Rahmstorf that the rate of global sea level rise has increased with time (and this rate is faster than the average over the last few thousand years). Whether or not you can detect an acceleration in a single tide gauge record is really beside the point, as I said a few days ago.
123467. shdwsnlite at 10:41 AM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        @ 18 Berényi Péter..-- you posted: New York tide gauge http://www.pol.ac.uk/psmsl/pubi/rlr.annual.plots/960121.gif http://www.pol.ac.uk/psmsl/pubi/rlr.annual.data/960121.rlrdata No 20th century acceleration at New York tide gauge. Not a bit. Some deceleration, if anything. How did you reach that conclusion? What was the process?
123468. kwinters79 at 10:36 AM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        #18 Berényi Péter, You're claiming you can eye-ball a single tide guage and determine if the global sea-level rise is accelerating or decelerating? Or even a few individual tide guages? That's amazing! In #7 you wrote: "The 190 cm figure is baseless, Vermeer & Rahmstorf 2009 should be retracted as well." I'm sure it will, if (and only if) someone comes along to point out an actual flaw in their methodology or conclusions. But eye-balling individual tide guages doesn't accomplish that.
123469. Berényi Péter at 10:28 AM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        #15 shdwsnlite at 09:26 AM on 25 February, 2010: "The more input, the more eyes on a problem the more self correcting for errors" Agreed. This is what I am trying to do here. Unfortunately most guys can only quote authoritative sources instead of having their eyes on the problem itself. I am prone to err as anyone, correction is welcome. However, in this topic I have not seen a valid one yet.
123470. Berényi Péter at 10:17 AM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        #10 Jeff Freymueller at 07:39 AM on 25 February, 2010: "Vermeer and Rahmstorf's post at RealClimate last August, which appears to be where they spotted the error" OK. In that post they say: "To constrain the value of a – which dominates the 21st Century projections — one needs to look at the “new rise”. How much has sea level rise accelerated over the 20th Century, in response to rising temperatures? That determines how much it will accelerate in future when warming continues" http://www.realclimate.org/index.php/archives/2009/08/ups-and-downs-of-sea-level-projections/ Sounds reasonable. Let's see. PSMSL (Permanent Service for Mean Sea Level) tide gauge data from Proudman Oceanographic Laboratory http://www.pol.ac.uk/psmsl/datainfo/ http://www.pol.ac.uk/psmsl/psmsl_individual_stations.html New York tide gauge http://www.pol.ac.uk/psmsl/pubi/rlr.annual.plots/960121.gif http://www.pol.ac.uk/psmsl/pubi/rlr.annual.data/960121.rlrdata No 20th century acceleration at New York tide gauge. Not a bit. Some deceleration, if anything. If global sea level rise is accelerating nevertheless, we can conclude that New York is accelerating upwards on a slightly faster rate. Odd enough. There are quite some tide gauges in PSMSL with long records. Would anyone set about computing acceleration for each one? It is not difficult, just time consuming. BTW, acceleration should be more precise than average rate of rise, since crustal slabs are not particularly brisk.
123471. Tom Dayton at 09:58 AM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        shdwsnlite, you sure sound like a scientist! I am one, and I agree with you completely.
123472. shdwsnlite at 09:26 AM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        Let me start off on my first post here and say I am not a scientist and I admit that reading through these posts makes my brain hurt sometimes. I am trying to learn though. I do have a question for Berényi Péter...in your self sufficiency of logic and truth suppose an error creeps in to your work which results in your conclusion being in error. You review your work following the same line of thought and as the process is unchanged then the error remains. In your eyes then your result is "Truth" but ultimately it is false. That is the benefit and need of reviewers and the community at large. The more input, the more eyes on a problem the more self correcting for errors.
123473. Tom Dayton at 08:55 AM on 25 February 2010
        Have American Thinker disproven global warming?
        Aha, Pierre-Normand! It was you that was that itch in the back of my brain while I was typing! I'm glad you wrote your version, because it is more technically accurate than mine. (I'm not technical.)
123474. Pierre-Normand at 08:52 AM on 25 February 2010
        Have American Thinker disproven global warming?
        That's funny; it seems Tom Dayton and I said exactly the same thing at the same time, though in different words. OLR is the (reduced) flow just in wake of the rock. Total whortwave emitted to space is the total water flow downstream from the leaky 'rock-dam'. Conservation of mass dictates that this flow is equal to the flow (non-reflected solar input) upstream from the dam, except in the non-steady state where the water level rises upstream of the dam (heat accumulates and temperature therefore climbs below the atmospheric greenhouse-blanket)
123475. Berényi Péter at 08:50 AM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        #8 Albatross at 06:51 AM on 25 February, 2010: "If you can convince the reviewers and scientific community that your analysis and projections are both superior and reliable, then I will accept your lower estimate until such time as newer evidence suggests otherwise" Man, try to think for yourself. It is not so difficult. Of course I don't have any estimate of my own. I just put two estimates side by side, one from Vermeer & Rahmstorf, from Siddall's retraction letter the other one. I care neither for reviewers nor the scientific community, but I do care for logic & truth. Appealing to authority is NOT the way science is done. Not even scientific authority is competent in this respect. As long as you are able to understand stuff, you are self sufficient.
123476. Jeff Freymueller at 08:42 AM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        #12 joseph, I did simplify it considerably (maybe too much). Siddall et al. defined the equilibrium sea level in terms of the inverse hyperbolic sine of a quantity that was linear in temperature. The modeled sea level then follows a differential equation of which the equilibrium sea level as a function of time is the inhomogeneous part. dhogaza's explanation (#11) is better than mine was.
123477. Cowboy at 08:39 AM on 25 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        "Cowboy @ 86, If you shared a bank account with Mrs Cowboy and you put in $1000 a month, and each month you found the balance rose by only $500 a month, you would know that Mrs Cowboy was spending $500 more a month than however much she were putting in. You would not need to tag all of the $1 bills as being "hers" or "yours" to know that she were a net drain on your bank account." However, if I was ESTIMATING that I was putting in $1000 a month when it could actually vary between $500 and $1500, and if she was randomly putting in anywhere between $10000 and $20000 a month, and we did not reconcile to actual bills and bank fees for each of us that month, then having $500 at the end of any particular month would be meaningless with respect to whether I was actually on net, contributing to overall wealth or debt. Accounting can be meaningless for taking action without actual, exact transaction receipts, account numbers (tags) and a ledger over a statistically significant period of time.
123478. Pierre-Normand at 08:35 AM on 25 February 2010
        Have American Thinker disproven global warming?
        It is my understanding that OLR at the top of atmosphere mustn't be confused with the total long-wave radiation emitted by the whole Earth+atmosphere system. Conservation of energy dicrates that under steady state conditions the latter rather than the former must be equal to incoming solar radiation (minus reflected shortwave energy). So, when Ramanathan speaks of a reduction of OLR, he is not speaking of a reduction in the total longwave emitted to space that satellites measure. His Figure 1 also make that clear. Total longwave emissions include longwave from the surface that the atmosphere is transparent to. When greenhouse gasses trap more longwave radiation coming from below the top of atmosphere, then less OLR is emitted from there. But this is compensated when the surface heats up and more longwave from the surface escape through the 10-micron window (roughly). Under steady CO2 increase, as occurs now, steady state isn't achieved and there is a net energy imbalance of 4W/m^2 (also caused by water vapor feedback). This is much smaller than the total OLR reduction Ramanathan speaks of. Those are apples and oranges. Under steady state (no more CO2 variations), the 4W/m^2 imbalance would disappear but the constant large OLR reduction would keep the Earth from cooling back.
123479. Tom Dayton at 08:35 AM on 25 February 2010
        Have American Thinker disproven global warming?
        Gary, Following up Doug's comment: You (Gary) seem to be assuming there is a rule requiring constancy of the proportion of IR leaking out past CO2 in the CO2-absorbing wavelengths, versus leaking out in other wavelengths. Or maybe just that the amount leaking out in other wavelengths must remain constant while the amount leaking out in CO2-absorbing wavelengths decreases. There are no such rules. CO2 molecules bang into other molecules (both gas- and non-gas molecules), thereby transferring some of their energy. Also, CO2 molecules emit IR in directions that get it absorbed by non-gas molecules. All those other, non-CO2, energy-recipient molecules then go about their business, doing whatever they do with that energy, including transferring it to yet other molecules gaseous and non-gaseous. That energy is perfectly capable of eventually turning into IR in wavelengths that are not absorbed by CO2. Some of that IR will head out to space, unimpeded by CO2. In that way, IR that is blocked by CO2 can eventually work its way around the CO2 roadblock. Analogy: In a small stream (outgoing IR), put in the middle a rock (CO2) that is short enough to allow water to flow over it (IR leaking through CO2), but tall enough to noticeably impede the flow (IR absorbed by CO2). Ensure that the rock is not as wide as the entire stream (CO2 does not absorb all wavelengths of IR). Consequence 1: The amount of water flowing over the rock is less than the amount of water that was flowing in that exact rock-occupied area before the rock was there. Consequence 2: More water is flowing through the stream on either side of the rock. A second misconception seems to be that the only energy trying to escape from Earth at any given moment is the energy that came in from the Sun the moment before. The misconceived argument seems to be that consequently the amount of energy escaping cannot be larger than the amount of energy that came in literally moments before. But in fact, the amount of energy trying to escape depends on the amount of energy (well, heat energy--temperature) that is currently residing in the Earth's system. That resident amount of energy increases by accumulation due to blockage by CO2. In the stream analogy: If the rock in the middle is wide enough and tall enough, water will accumulate behind the rock. If the rock is really tall and nearly as wide as the stream, water will accumulate despite the increased flow at the edges. If you plop down a tall enough rock initially, or quickly create an equivalent pile of little rocks by plopping them down one at a time really fast, water will accumulate before the flow on the edges increases. That mass of accumulated water, not just the water coming from upstream, is what is now driving the amount of water flowing around the edges. So there is a lag between the accumulation and the increased edge flow. The exact consequences of how much water accumulates, how much flow increases at the edges, and how much flows over the rock, depends entirely and thoroughly on the exact details of the rock's height and width, the amount of water coming down the stream toward the rock, the obstructions at the edges, and so on. It gets even more complicated if you continually increase the height of your little dam by adding pebbles on top of it. In the Earth's system, the same things happen. The exact consequences--how much energy leaks out on either side of the CO2-absorbing wavelength bands--depend on the exact details of how much energy is coming in from the Sun, how fast CO2 is increasing, and so on. The bottom line is that it is perfectly feasible to have simultaneously, increased energy accumulation, increased outgoing energy at non-CO2 wavelengths, and decreased outgoing energy at CO2 wavelengths.
123480. johnd at 08:13 AM on 25 February 2010
        The Dunning-Kruger effect and the climate debate
        The Dunning-Kruger effect is in fact a byproduct of the Peter Principle. That is, a person continually moves higher until they reach a level that is beyond their level of competency.
123481. joseph449008 at 08:01 AM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        

        In the paper, they modeled sea level as being a function of a*dT+b (they used a different notation; this matches Vermeer and Rahmstorf in RealClimate and is simpler. dT is change in temperature).

        That sounds way too simplistic. I haven't taken the time to read the relevant papers, though. A model of SLR should consider ice melt and thermal expansion separately. Thermal expansion is non-linear. I was looking at density of water given its temperature and salinity, and a quadratic equation fits it quite well. It's complicated to do an ocean estimate because the temperature of ocean water varies with depth, and modeling this seems non-trivial by itself. Ice melt looks even more complicated. You can probably come up with a model for 'equilibrium' ice volume. But then the speed of ice melt is tricky. This would have to depend on the difference between the current ice volume and the equilibrium ice volume, times the surface area of heat transfer.
123482. dhogaza at 08:00 AM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        Berényi Péter sez:

        Siddall's retraction letter says: "we overlooked that the simulations of the twentieth and twenty-first centuries are sensitive to this time step, which led to an overestimation of the sea-level response to warming in the simulations for these centuries

        He's assuming that "response" means "sea level rise". That's not the fact. From Rahmstorf's original criticism at Real Climate, which eventually led to the correspondance which led to Siddal retracting the paper:

        Siddall et al. in contrast find a time scale of 2900 years, but introduce a non-linearity in the equilibrium response of sea level to temperature (see their curve in Fig. 1 and footnote 3 below): it flattens off strongly for warm temperatures.

        The response which is overestimated is this flattening of sea level rise, not sea level rise itself. Remove that overestimated flattening and the sea level rise estimates ... rise! Here's more of Rahmstorf's RC note on this:

        The reason for both the long time scale and the shape of their equilibrium curve is that this curve is dominated by ice volume changes. The flattening at the warm end is because sea level has little scope to rise much further once the Earth has run out of ice. However, their model is constructed so that this equilibrium curve determines the rate of sea level rise right from the beginning of melting, when the shortage of ice arising later should not play a role yet. Hence, we consider this nonlinearity, which is partly responsible for the lower future projections compared to R07, physically unrealistic. In contrast, there are some good reasons for the assumption of linearity (see below).

        Note that the retraction thanks Vermeer and Rahmstorf for bringiing the overestimation (of flattening) to their attention, so Siddal at least is convinced they're right. Berényi Péter, why did you assume "response" meant "sea level rise"? It's a reasonable guess, but you don't have to guess, you know, you can always read instead.
123483. Jeff Freymueller at 07:39 AM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        #7 Berényi Péter, it helps to read the Siddall paper, and also Vermeer and Rahmstorf's post at RealClimate last August, which appears to be where they spotted the error (especially check the update just before the footnotes): http://www.realclimate.org/index.php/archives/2009/08/ups-and-downs-of-sea-level-projections/ In the paper, they modeled sea level as being a function of a*dT+b (they used a different notation; this matches Vermeer and Rahmstorf in RealClimate and is simpler. dT is change in temperature). The a and b are determined empirically by fitting the data. Their error caused them to get incorrect estimates for both a and b. Their retraction mentions only the effect on a. If you correct the error in their code, then their model no longer fits 20th century sea level rise (it underpredicts it), so its prediction for the 21st century obviously can't be trusted. If you increased b so that their model fits 20th century rise, then you would get a larger 21st century prediction. This might mean that you can't model both post-LGM and 20th century sea level change with the same a and b. (They mention a second error, and I don't know what effect that has, but it really doesn't matter because the entire result needs to be thrown away and redone). Or better yet, revert back to Rahmstorf's 2007 paper or to Grinsted et al. (2009), both of which lack errors, and fit the historical data. These papers predict higher future rates, by the way. I have not looked at Vermeer and Rahmstorf (2009), just downloaded it but don't have time to read it now. By the way, your statement 2 is based on your own misinterpretation (jumping to conclusions). So your final argument is meaningless.
123484. Dikran Marsupial at 07:34 AM on 25 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        Cowboy @ 86, If you shared a bank account with Mrs Cowboy and you put in $1000 a month, and each month you found the balance rose by only $500 a month, you would know that Mrs Cowboy was spending $500 more a month than however much she were putting in. You would not need to tag all of the $1 bills as being "hers" or "yours" to know that she were a net drain on your bank account. Likewise the "mass balance" argument holds without having to "tag" any of the CO2. Do read the webpage by Ferdinand Englebeen on CO2 measurements linked by Tom @ 87, it really is an excellent resource (it includes an example similar to the above).
123485. Doug Bostrom at 07:19 AM on 25 February 2010
        Have American Thinker disproven global warming?
        garythompson at 06:04 AM on 25 February, 2010 Gary, I think you're getting a bit lost trying to deal with comments while still leaving John's issues unaddressed. Could you go through John's remarks on your article point-by-point here, just so everybody's on the same page? Also, you should probably correct this sentence in the portion of your article where you discuss Lindzen & Choi 2009: "In the paper, the data showed that OLR increased when sea surface temperatures increased, so this is in direct contradiction to the AGW hypothesis that less OLR should be emitted since more CO2 is absorbing it and warming the planet." That's not really a sound conclusion, first because OLR increases in model predictions, secondly because Lindzen & Choi used undifferentiated OLR wavelengths thus making it impossible to discern C02 effects on the overall radiation, meaning you can't form a conclusion about C02 from their paper.
123486. tobyjoyce at 07:15 AM on 25 February 2010
        Have American Thinker disproven global warming?
        @garythompson, I think you have shifted ground, but are not really getting anywhere. Quick explanation from www.realclimate.org: "The way the greenhouse effect really works is that adding CO2 reduces the infrared out the top of the atmosphere, which means the planet receives more solar energy than it is getting rid of as infrared out the top. The only way to bring the system back into balance is for the whole troposphere to warm up. It is the corresponding warming of the low level air that drags the surface temperature along with it ..... " Ok, so we would expect a reduction in OLR over the absorption CO2 range. It seems to be that is visible in ALL the papers under discussion. There is also excellent agreement between observations and the models. Let me draw your attention to Fig. 5 of the Griggs & Herries (1996) paper - this also plots the differences, but bands of statistical significance from 0 are marked with vertical grey bars. You can see a good collection around the 700-800 cm^-1 (CO2)region. This seems to me to put paid to the idea that the 1997 & 1970 observations are the same. Your fallback position is that the base models are somehow mistaken. As I pointed out, the models agree with the observations. You agree with the observations, so how can you challenge the models? Incidentally, climatology could not proceed without models, not could a lot of physical science (astrophysics, nuclear physics, to name two branches). Remember the old adage of the philosophy of science "All observations are theory-laden"? You need to toss aside your ideological blinkers. I agree with Ricardo that "Your ending comment in the AT piece is thereby entirely unwarranted." The only fallback seems to be Lindzen & Choi (2009) but that has already been thoroughly critiqued elsewhere http://www.realclimate.org/index.php/archives/2010/01/lindzen-and-choi-unraveled/
123487. Tom Dayton at 07:08 AM on 25 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        Cowboy, you wrote "...show me that there is a 'tag' on anthropogenic CO2 to distinguish it from environmental CO2, and that there is a global-wide sampling using those tags...." Okay: The CO2 Measurements page has detailed explanations and links. Do be sure to click on the links, because that page is only a summary.
123488. joseph449008 at 07:00 AM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        

        This is the amount of warming expected for some of the lower emission scenarios. At that time of the last interglacial, sea levels were at least 6 metres higher than present levels. So while we expect sea levels to rise up to 2 metres by 2100, they will continue to rise afterwards to at least 6 metres.

        It's likely more than 6 meters. Sea level changes due to ice melt are very slow to materialize, and the last interglacial was relatively short-lived.
        Response: Good point. Kopp found it very likely (95% probability) that in the last interglacial, sea levels were at least 6.6 metres higher than today. It's likely (67% probability) that sea levels exceeded 8 metres (Kopp 2009). Note that temperatures during the last interglacial were around 2 degrees warmer than now. This is the amount of warming expected for some of the lower emission scenarios. This is important to realise when you compare current emissions to the IPCC scenarios. I will be posting about that later today (if time permits).
123489. Albatross at 06:51 AM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        Re # 7: "The 190 cm figure is baseless, Vermeer & Rahmstorf 2009 should be retracted as well." If you are so confident in your science and analysis (doubtful if you have done any) then please submit a comment/rebuttal to PNAS requesting a retraction of Vermeer and Rahmstorf, or even better, submit a paper describing your own data, methodology and analysis and conclusions. If you can convince the reviewers and scientific community that your analysis and projections are both superior and reliable, then I will accept your lower estimate until such time as newer evidence suggests otherwise.
123490. Jesse Fell at 06:48 AM on 25 February 2010
        Have American Thinker disproven global warming?
        Gary, I'm not sure I agree with you (I'm huffing and puffing to catch up with all you heavy weights), but I want to thank you for discussing this issue like a gentleman. If only more blogs about this critical topic were conducted in this grown-up style!
123491. Cowboy at 06:30 AM on 25 February 2010
        What would happen if the sun fell to Maunder Minimum levels?
        "The argument that the rise in CO2 is anthropogenic doesn't rely solely on correlations, a simple piece of accountancy is enough to verify that it is true. The annual increase in atmospheric carbon is about half the annual emissions (fossil fuel + land use), and the remaining carbon has to go somewhere. This excess carbon must be being taken up by the natural environment (oceans + terrestrial biosphere) somewhere, which proves that the natural environment is a net sink (over a full annual cycle)." I'll consider that at least in part if you can show me that there is a 'tag' on anthropogenic CO2 to distinguish it from environmental CO2, and that there is global-wide sampling using those tags that shows CO2 levels by source that is statistically significant at a high degree of certainty. Otherwise, I'm afraid, it sounds like a premise based on what is essentially an assumption... And by the way, we will need those tags to differentiate between 'natural' environment vs environment impacted by mankind for it to be at all meaningful. Without differentiation between fuel generated CO2 and 'residual' CO2 due to mankind's impact on CO2 sinks, I don't see how your alleged equilibrium shows anything. In that differentiation between 'natural' environment vs environment impacted by mankind you will, of course, need a control rather than relying on assumptions... good luck with that...
123492. Berényi Péter at 06:19 AM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        Global sea level linked to global temperature http://www.pnas.org/content/early/2009/12/04/0907765106.full.pdf Vermeer & Rahmstorf 2009 write: "When applied to observed data of sea level and temperature for 1880-2000, and taking into account known anthropogenic hydrologic contributions to sea level, the correlation is >0.99, explaining 98% of the variance" Unfortunately it does not make sense. Since observed sea level data are taken from IPCC AR4 WG1 where twentieth century sea level rise is estimated to be 14±10 cm (note the wide error margin), a 0.99 correlation during calibration phase is meaningless for a model with built-in exponential behavior. The 190 cm figure is baseless, Vermeer & Rahmstorf 2009 should be retracted as well. Even more important. Contrary to your statement "The low sea level rise is found to be in error. While some are spinning this result to imply no sea level rise, in actuality it increases our confidence in high sea level rise" Siddall's retraction letter says: "we overlooked that the simulations of the twentieth and twenty-first centuries are sensitive to this time step, which led to an overestimation of the sea-level response to warming in the simulations for these centuries" http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo780.html Overestimation. The plain meaning is that the 82 cm figure is too large, even for the worst model scenario. We have two statements: 1. Sea level rise during 21st century is 75-190 cm 2. 7-82 cm is an overestimation They are extremely hard to be seen as strengthening each other.
123493. garythompson at 06:04 AM on 25 February 2010
        Have American Thinker disproven global warming?
        the point i was trying to raise was - why do we need to correct for water vapor and surface temperatures when there are statements in peer reviewed papers that we don't need to do this in order to see the reduction in OLR associated with CO2 absorption? an example - according to the paper by Ramanathan entitled "Trace-Gas Greenhouse Effect and Global Warming" (http://www-ramanathan.ucsd.edu/RamAmbio.pdf), the author states on page 3 (which is really labeled page 189 since it was in a larger journal i guess) under the section Anthropogenic Enhancement of the Greenhouse Effect - "an increase in greenhouse gas such as CO2 will lead to a further reduction in OLR." notice there is no clarifying statement about having to use model simulated graphs to 'correct' for surface temperatures and water vapor before seeing that OLR reduction. and in the paragraph right above that the author states - "since the emission increases with temperature, the absorbed energy is much larger than the emitted energy, leading to a net trapping of longwave photons in the atmosphere." here the author stated clearly that even taking into account higher emissions from warmer surfaces, the net will still be a reduction. The Griggs and Harries - 2007 paper that Philippe Chantreau pasted a link to was great - thank you. i'm not all the way through it yet (and probably won't until several days the way this week is going....) but i did skim it and read the conclusions. here are a few quick takeaways that will probably get clarified or amplified once i've finished the paper. Fig. 4 showed the delta in OLR from 2003-1970 and again, i don't see how you can look at that graph and claim anything other than no change with regard to wavelengths in the CO2 absorption range. and with regard to the using the model to tease out the water vapor and sst changes - in the appendix the temperatures for 2003 were mostly equal to or lower than 1970 so that should've skewed the actual OLR measurements lower in 2003 (which it didn't). and in the conclusions the authors state that there is "perhaps a deficiency in the modeling due to aerosol or continuum effects." and in all three of the papers i cited in the article (and this new one listed above) the actual measured data show flat or increasing amounts of OLR which is in direct opposition to what AGW predicted in the Ramanathan paper. The simulated, modeled graphs (removing water vapor contributions and sst differences) show a reduction in OLR associated with CO2 absorption but again my whole take on this was to place more value in the real, actual measurements instead of the adjusted data. I understand what the authors (and many of you in your explanations provided here) are doing and why you are doing it and why the authors came to their conclusions (which are in direct opposition to the conclusion i came to in my article). we have a difference of opinion as to which data set has more value. that doesn't mean i'm calling the authors (or anyone here) frauds or degrading them or trying to discredit them. again, let me be clear, i have the utmost respect for the scientists who write these papers (as well as those on here whom i've conversed with) and i believe they are the tops in their field and would never do anything devious or underhanded to misrepresent data to help their argument. I think i've clarified that enough now. Philippe Chantreau - thanks also for your comments on my back of the envelope calculations - i didn't get to devote the time to digest all of your comments the way they deserve but i will. and i recognize the exercise is difficult but has anyone used the BT delta numbers (even the ones that were generated from the models removing SST and water vapor impacts) in these papers, converted that to what predicted temperature rise would be predicted for Earth (form say 1970 to 2006) and then compared that to GISS, HADCRUT3, etc. measurements? I would think this would be a valuable exercise. and contrary to a post (Riccardo #64) about me not even getting the order of magnitude right (which i did, 0.23 C and 0.73C are the same order of magnitude) my admittedly simple model led me to the conclusion that even a -1K BT delta isn't enough to validate the AGW model. i had to resort to that simple model because i couldn't find the calculation done but then again i don't have the extensive body of knowledge and connections that people here have - hence the reason for hanging out with you and the Real Climate blogs.
123494. Charlie A at 06:00 AM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        An interesting peer reviewed article published in Geophysical Research Letters is :"Recent global sea level acceleration started over 200 years ago?", Jevrejeva, Moore, Grinsted, and Woodworth. GRL 2008. http://www.pol.ac.uk/psmsl/author_archive/jevrejeva_etal_1700/2008GL033611.pdf Only 4 pages long and a reasonably easy read, but you can also just skip down to Figure 3, which extracts from the sea level instrumental record a basic oscillatory trend of 60 year period which is superimposed on an accelerating trend starting in the late 1700's.
123495. barry1487 at 06:00 AM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        From the abstract: "First, we tested the sensitivity of our results to the length of the time step used in the integration of the model for the period of deglaciation, which we found to be robust. However, we overlooked that the simulations of the twentieth and twenty-first centuries are sensitive to this time step, which led to an overestimation of the sea-level response to warming in the simulations for these centuries." Aren't they being a bit more specific than saying that their methods are wrong and their conclusions are simply invalid? Are they not saying that their methodology led them to overestimate sea level rise?
123496. Philippe Chantreau at 05:59 AM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        Nice work John. And once again more references than I can look at.
123497. tobyjoyce at 04:08 AM on 25 February 2010
        Have American Thinker disproven global warming?
        @garythomspon (#49), Nice try, and I do like your calm way you have elected to debate this, but I think your amended post on AT has a logical fallacy. You argue concerning the chart #3 that shows the 1907 & 1997 difference that "Since half the wavenumbers experienced a decrease and the other half experienced an increase, the data is not compelling enough to make conclusions either way with regard to OLR for these wavenumbers associated with CO2 absorption." What you are saying is that the curve of OLR differences averages out as 0 (approx.), so we must accept a Null Hypothesis that the difference between 1997 and 1970 is 0. First of all, the model curve also averages out as zero so should we not therefore accept the model as a valid prediction? But you are arguing that the model is wrong - hence the fallacy. Hardly a disproof of a key component of the theory of Global Warming. Further, IMHO, where you are going astray is that you are assuming a homogenous process underlying the curve. However, you can see the CO2, O3 & CH4 absorption bands highliged in grey. The question is - are the separate averages in the absorption bands for the three greenhouse gases significantly different from 0? Not sure about 02 and CH4, but the CO2 band seems to be, though I admit there is not a statistical test in the paper to demonstrate that conclusively. Certainly the model seems to be a good fit in the CO2 band. I think the authors are justified in claiming the following: "Changing spectral signatures in CH4, CO2, and H2O are observed, with the difference signal in the CO2 matching well between observations and modelled spectra.The methane signal is deeper for the observed difference spectrum than the modelled difference spectrum, but this is likely due to incorrect methane concentrations or temperature profiles from 1970. In the future, we plan to extend the analysis to more spatial and temporal regions, other models, and to cloudy cases. " This is good science - the authors publish their results through peer-review, are clearly concerned to establish the accuracy of their model, and clearly intend to do further work to verify their findings. Not the sort of people who deserve to be characterized as rogues and frauds, as your commenters on AT seem to believe.
123498. Jeff Freymueller at 04:07 AM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        The reaction to this one really has been in the up is down category. Many or most scientists who work in glaciology, and many who study sea level, consider the IPCC's projections to be only a lower bound on future sea level rise. That is, actual sea level rise is almost certain to exceed the IPCC projections. Why? Because the IPCC assumed that glacier flow would not speed up as temperatures warm. Their reason for excluding a contribution from enhanced glacier flow in the future is that the uncertainties in future projections of it were large based on the literature as of the IPCC cutoff date. In the Third report a few years ago, they had tried to include this contribution, but this time they did not. There are two problems with the IPCC's decision. First, a slowdown in glacier flow with warming temperature is very, very unikely. What we have seen so far is that glacier flow is speeding up with increasing temperature. It is just hard to predict how much more speedup there will be in the future. Second, the major contribution to sea level from Greenland and Antarctica does not come from meltwater running off, but from glaciers flowing faster and dumping ice into the ocean, where it melts. So the bottom line is that the IPCC projection excluded a component that is highly uncertain, but almost certainly positive. Sea level rise will almost certainly be faster than the IPCC projection, but there is disagreement on how much faster. That's the context of the Siddall paper. They got a relatively low projected future rate, which would have been a fairly big deal given that a lot of other work in the last few years has pointed to much higher rates. John is absolutely right -- the authors retracted their paper's conclusions of low future sea level rise, because when they fixed their error, they get a much higher future prediction. They explained the error in the retraction letter. Their basic method was sound. But the time step they used in the integration of their model was too long to be used for 20th century sea level rise and 21st century predictions. Effectively, by using a time step that was appropriate only for reconstruction over a much longer time scale, they smoothed out the recent and projected rise, getting a lowball estimate.
123499. SLRTX at 03:06 AM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        "Skeptics" (we'll call them that for now) confuse the facts supporting anthropogenic climate change (ACC), and the effects of those changes. Estimations of changes to sea levels falls into the category of effects of ACC. Whether or not the models to project the effects of ACC were off a bit still does not change the facts supporting ACC.
123500. chparadise at 03:04 AM on 25 February 2010
        Misinterpreting a retraction of rising sea level predictions
        In a way, this paper --> investigation by another group --> questions raised --> voluntary retraction is exactly the sort of way in which science is supposed to work. However, it's going to be tough convincing some of the non-scientists of this, since they don't know just how well scientists police themselves.

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