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Comments 126451 to 126500:

126451. Tom Dayton at 03:18 AM on 23 November 2009
        The albedo effect
        Henry, the Wikipedia entry you quoted says "...re-emit much of the energy." Your interpretation of "re-emit" meaning "the molecule becomes sort of like a little mirror...and the molecules start reflecting" is completely wrong. RKM.com.au provides an excellent animation (at the top right of the page), an accompanying static diagram (at the lower left of the page) and a step-by-step textual explanation of it all (at the right side of the page). Please don't merely skim all those as you seem to usually do. Study carefully. Notice that there is no second infrared photon hitting the molecule and being reflected. Instead, the molecule "re-emits" the same energy it just absorbed. "Re-emit" means "emit the same energy it just got." The molecule stores the energy it absorbed by putting it into vibration of the bonds among the atoms in the molecule, as is explained in the text accompanying that picture. The energy in those vibrations then is emitted as infrared radiation, with the result that those vibrations cease. The energy is neither destroyed nor created. It merely changes location and form from photon to bond vibration and back to photon. Molecules have several modes of vibration; animations of those are provided by the Journal of Chemical Education site (see Figure 2 there). Each of those modes can contain energy independently of the other modes, and several amounts of energy can be contained by each of the modes. So even if a molecule has absorbed one photon's energy, it has enough storage capacity to absorb more. The re-emission happens almost instantaneously after the absorption that triggered it, which means the molecule's storage is freed up almost instantly after it is filled. But if occasionally a photon does hit the molecule while the molecule cannot absorb any more, the photon does not get reflected because of that; it does indeed just pass through/around. (Remember, a photon is actually/also a wave packet.) Reflection is a completely different phenomenon that is governed by oompletely different laws, as we have explained to you before. An excellent explanation of greenhouse gas bonds, vibrations, energy storage, and energy re-emission is in David Archer's free "Lecture 6: What Makes a Greenhouse Gas". (It's in Chapter 4--the sixth lecture in the overall list of lectures.)
126452. chris at 02:36 AM on 23 November 2009
        What do the hacked CRU emails tell us?
        A general point There are lots of vague references to what are presumably rather specific emails. If anyone makes a comment about a particular point, why not specify exactly what email(s) the point refers to. Then we can assess the context etc. This relates to post #13 (HumanityRules extraced single sentence), post #15 (Truthseekers list), post #19 (Nickle's PhD comment) etc. HumanityRules (post #13) has linked to the hacked archive. So simply put the date of the email(s) that you are referring to, rather than posting single extracted sentences or making unspecified assertions.
126453. Henry Pool at 01:36 AM on 23 November 2009
        The albedo effect
        Hi Riccardo: where did you get this formula? The concentrations measured in what units? Quote from Wikipedia (on the interpretation of the greenhouse effect); "The Earth's surface and the clouds absorb visible and invisible radiation from the sun and re-emit much of the energy as infrared back to the atmosphere. Certain substances in the atmosphere, chiefly cloud droplets and water vapor, but also carbon dioxide, methane, nitrous oxide, sulfur hexafluoride, and chlorofluorocarbons, absorb this infrared, and re-radiate it in all directions including back to Earth." The way I understand this process is as follows: Water and carbon dioxide behave similarly when exposed to infra red radiation. Each molecule accepts one or more photons. Once this transaction is completed the molecule becomes sort of like a little mirror to infra red radiation (at those wavelenth bands where absorption takes place) and the molecules start reflecting the infra red. Because of the random position of the molecules we may assume that at least 50% of that radition from earth is radiated back to earth. The process repeats itself. Obviously when the sun's radiation hits the water vapor and the carbon dioxide the same thing occurs, but now 50% is reflected out to space. I assume/ would think that if the radiation stops, the photons in the molecule are converted to kinetic energy to any of the molecules in the immediate vicinity How do you understand the definition? Consequently I also disagree with you on your last point. The ozone is very little. How much UV do you think can be absorbed? Once the molecules are saturated the UV is blocked - like a mirror - and light being what is does best, it has to move, so it moves.....out!! The thicker the layer of ozone, the more UV light is reflected, hence the increase in earth's albedo.
126454. Nickle at 01:14 AM on 23 November 2009
        What do the hacked CRU emails tell us?
        The "trick" to "hide the decline" dates from 1999. As 1998 was a record hot year, it is hard to imagine what real decline in temperatures the sceptics/deniers think was occurring that needed to be hidden. You're thinking the wrong way round. It's not that they were using a 'trick' to hide a divergence. They were using a trick to hide a 'decline' That was the language used. I've no reason to believe that they didn't mean what they said. ie. It's a case of manipulating things to fit the hypothesis, not trying to explain what doesn't fit the hypothesis. Combine that with all the other details in the emails and it shows a particular unpleasant group of people. Imagine plotting to get a PhD removed from a student because their results were awkward? In reality, its a disaster for climate change advocates. They have been hiding data, and its clear they have done this now. They have also talked about destroying data that is subject to a FOI request. That is a criminal offence in the UK
126455. Turboblocke at 01:03 AM on 23 November 2009
        What do the hacked CRU emails tell us?
        The "trick" to "hide the decline" dates from 1999. As 1998 was a record hot year, it is hard to imagine what real decline in temperatures the sceptics/deniers think was occurring that needed to be hidden.
126456. Riccardo at 00:54 AM on 23 November 2009
        The albedo effect
        Henry Pool, still off topic here, but for you knowledge a reasonable aproximation for the differenze in forcing of CO2 alone in the atmosphere is deltaF=5.35*ln(C2/C1) in W/m2 with C1 and C2 two CO2 concentrations. You can play around with those numers if you like. You idea of limited absorption is absurd and this is once more missing basic physics. It would require each molecule to stay in an exited state forwever which is simply impossible in any real world. Saturation experiments has indeed been done, but they require ultrafast high power lasers As for the future closure of the ozone hole, yes, it will be a negative forcing localised in the stratosphere which is expected to cool somewhat less; not due to reflection, though, but absorption of some UV.
126457. Henry Pool at 23:09 PM on 22 November 2009
        The albedo effect
        @ Steve and Tom on 56 I note that there are some unbelievably big variations in the AHF measured. Like in my country of birth (Holland) they measured 4.2 W/m2. However, globally, it is reportedly only 0.03 W/m2. How can that be? I think there are some missing data, mostly from the underdeveloped countries?> On the subject of where to easily note global warming: Note that nuclear facilities are all placed near oceans or seas because they need tons and tons of water to cool. The AHF warming goes mostly into the oceans.... In many places, AHF takes place mostly near mountains or mountain ranges. (constant water supply for human activities)
126458. Henry Pool at 22:46 PM on 22 November 2009
        The albedo effect
        @Tom on 55 The tests you refer to all compare air with 100% CO2. That was exactly not the idea of my experiment. I am a chemist. I know that if you change concentrations (in a solution) you might get different properties (as a whole). In my experiment, I wanted to know what difference 350 ppm's CO2 makes on heat retention. Just admit it: at that concentration it is probably not even measureable in my experiment.... However, a doubling of a release of energy (to simulate the doubling of the earth's population) in our (earth)vessel was easily measurable. Or do you also doubt the outcome of my experiment 1?
126459. TruthSeeker at 22:25 PM on 22 November 2009
        What do the hacked CRU emails tell us?
        Interesting. You provide anictdotal evidencen to suggest that Tree rings are no longer any good while I suggest that if they arn't currently any good who has evidece that they were ever any good.
        Response: The evidence that tree-rings are a reliable proxy can be found in Briffa 1998 that show tree-ring width and density show close agreement with temperature back to 1880. To examine earlier periods, one study split a network of tree sites into northern and southern groups (Cook 2004). While the northern group showed significant divergence after the 1960s, the southern group was consistent with recent warming trends. This has been a general trend with the divergence problem - trees from high northern latitudes show divergence while low latitude trees show little to no divergence. The important result from Cook 2004 was that before the 1960s, the groups tracked each other reasonably well back to the Medieval Warm Period. Thus, the study concluded that the current divergence problem is unique over the past thousand years and is restricted to recent decades. More on the divergence problem...
126460. Henry Pool at 21:34 PM on 22 November 2009
        The albedo effect
        on 52&54 yes we have strayed from the subject (although I still have good hopes that mostly the noted increase in ozone will bring us global cooling due to an increase in earth's albedo and a closing of the ozone hole) but I think this straying is and was necessary. We have touched on a new subject now: AHF. Maybe another post? Anyway, Tyndal proved that it was mostly water keeping our planet warm, and he was right about that. Don't forget that at about 70% RH you have about 1-1.5% water vapor in the air, compared to CO2 of 0.038% (which really is next to nothing compared to the H2O) the point that you, Riccardo, seem to forget is that you think that the "absorption" process is limitless. It is not.Every molecule can only absorb that much photons. After that the light must keep on moving, so where it it wanted to move (because the molecule is now full) it cannot. It cannot move through either (like it does through N2). so it has to scatter. At least 50% is scattered to out of space. I( did not provide prove for my experiment, because I donot have the equipment. But I can easily guess the outcome!
126461. Darren Lewin-Hill at 20:34 PM on 22 November 2009
        What do the hacked CRU emails tell us?
        TruthSeeker, refer to @dhogaza at the end of comment 10 re the evidence of the instrumental record. I guess you don't say the instruments have stopped working because the tree-rings don't agree. Comment 14 goes on to suggest that other factors may well be in play re the tree-rings. For example, I might grumpily say it's hot and that has been a good proxy for the outside temperature in the past (e.g. I tend to say it when it reaches about 25C inside), but while I'm away on a work trip my wife installs an air-conditioner and sets the thermostat at 22C - pleasant but not necessarily obvious. Having lazed away the weekend inside on returning from my trip, would I sit there looking in disbelief at a TV weather report of 37C, or go looking for another explanation (i.e. the new air-conditioner)? I don't think I'd be suggesting there was something wrong with the instruments of the meteorologists, do you? I'd also imagine that the tree-rings would have continued to be a good proxy had the conditions in which they formed remained continuous in the divergence period with the time when they more closely reflected temperature.
126462. Henry Pool at 19:29 PM on 22 November 2009
        The albedo effect
        Ok, I will go through all of your comments in more detail later. Are you people saying that in my experiment 2, there will actually be something of an increase in heat retention to obeserve? if yes, how much in the concentration range of 0.01 to 0.05 % CO2. I don't think a child can do this. I think I made a mistake by putting in air (Experiment 2), I think we must leave the water vapor out of it, just stick with the 80/20 N2/O2 and then add the 270, 350 and 500 ppm CO2 (we need to know exactly where we are going) These are the results I was hoping to find somehwere and never got it. even so, I think there will never be as much heat retention by CO2 as in experiment 1, between A and B.
126463. TruthSeeker at 17:19 PM on 22 November 2009
        What do the hacked CRU emails tell us?
        I am somewhat surprised by these responses. I find significant problems with the following discoveries in the emails: 1) Tree ring data is good when it supports the hypothesis, but must be hidden when it conflicts? None of you take issue with that? 2) Through the email text it is pretty clear that their approach is to validate data based on how well it fits to the hypothesis, not how well the hypothesis fits to the data 3) Why is it ok to obstruct the freedom of information act? What do they have to hide? 4) Why do they collude to exclude peer review of articles that question their hypothesis, I find it most disturbing since they use the lack of peer review to discredit the skeptics. This truly brings into question both their ethics and scientific agenda. The models have been notoriously inaccurate in making future projections, and now we find that even the week claims of model accuracy are nothing more than the result of massaged data. There is an old saying, that if you torture the data enough, it will confess.
126464. dhogaza at 16:16 PM on 22 November 2009
        What do the hacked CRU emails tell us?
        

        I'm not sure I understand why a change would occur in sensitivity, but I'm not a scientist.

        It doesn't matter that you're not a scientist, because they don't understand either. That's why the divergence problem is ... a problem! :) Seriously ... But they're working on it. You might google "Liebig's Law of the Minimum". In plain language, this essentially says that growth is typically limited by the most scarce resource/factor. For a tree up high near the specie's tree line, this is often temperature, often the number of warm days over a short period of summer. Lower down, you may find many more warmer days, the same precip, the same nutrients more or less, and growth patterns will be different because the scarcest resource might be (say) soil nitrogen. It's warm enough so the tree will grow rapidly enough to be limited by that rather than temps. Does this make sense to you? So the confounding factor as temps have warmed for some of the series might simply be that temperature is no longer the most limiting factor. Maybe precip has dropped. Maybe something else is going on. This is the kind of stuff they're working on - trying to understand what factors have changed to cause growth patterns to change. I think they'll work it out. Science typically does ...
126465. Tom Dayton at 15:39 PM on 22 November 2009
        The albedo effect
        Henry, there is even a video of an actual child explaining his actual experiment of the sort I previously pointed you to.
126466. HumanityRules at 14:24 PM on 22 November 2009
        What do the hacked CRU emails tell us?
        The emails have been archived in a searchable form here. http://www.anelegantchaos.org/cru I was wondering what peoples thoughts are on this comment from one "Despite its relatively small size, CRU has had (and continues to have!) a rather remarkable "fingerprint" in the world of climate science." I had wondered about the influence of this organisation.
126467. Darren Lewin-Hill at 14:12 PM on 22 November 2009
        What do the hacked CRU emails tell us?
        @dhogaza Thanks for further explaining that. I'm not sure I understand why a change would occur in sensitivity, but I'm not a scientist. That what was claimed to be hidden was in fact explicit in the literature is, I think, sufficiently reassuring. As for the denialists, I'm sure they'll continue to make capital of this stuff, but the point about the broader, and quite obvious, climate picture should serve as a powerful contradiction to their nonsense.
126468. Tom Dayton at 12:04 PM on 22 November 2009
        The albedo effect
        Henry, if you want to see the raw data used by Flanner so you can do the calculations yourself (see my previous comment on 22 November), you can get them from this web site he put up. He wrote there, "Globally, in 2005, this anthropogenic heat flux (AHF) was +0.028 W/m2, or only about 1% of the energy flux being added to Earth because of anthropogenic greenhouse gases." That page also has some other references, if you don't want to pay to see his journal article.
126469. SNRatio at 11:59 AM on 22 November 2009
        What do the hacked CRU emails tell us?
        For the science, this has minimal impact. I have seen a couple of comments from more skeptical scientists who in fact have gotten more confidence by seeing that these guys are almost obsessed with science. It will lead to even more focus on openness, quality and the peer review process. Very good. It wouldn't harm with a bit more focus on ethics, either. In the RC posting about this they pointed to Newton, who was no angel. OK, then I would say that Newtonian ethics is much more outdated than Newtonian mechanics :-) The political impact will be much bigger, but mostly short term. The IPCC will be more dependent on the science and the reasoning, and less on the authority of leading scientists. It may be a setback for international negotiations, but not for very long. And I think we may even get better and more robust policy measures this way. The most important thing in the current situation, is that the models have been somewhat oversold, and the IPCC estimates have not been as conservative as they should be. In addition lots of time and energy has been used unproductively on tree-rings, hockey-sticks and "unprecedented warming". Look at this discussion, too: The divergence problem is real, and interesting, but how much of current climate science depends on it, really? To me, it seems mostly to fuel denialists' attacks. The present situation, where feedback estimates tend to be reduced over time, is most unfortunate. James Hansen's old curves, using 4 deg/doubling, may increasingly be used as examples of "alarmism" by "skeptics" and among the leaked emails can be found what Kevin Trenberth wrote to Tom Wigley 20091014: "How come you do not agree with a statement that says we are no where close to knowing where energy is going or whether clouds are changing to make the planet brighter. We are not close to balancing the energy budget." This is of course relative to Trenberths very high standards, but still quite different from the impression of rather small uncertainties. Which is also borne out by the models not performing very well for the last decade. In fact, a few more years with little or no warming would show them to be in error - something that would not have happened with more conservative estimates. According to the models, the development of the last decade is a bit anomalous - I'm not sure it is, and something like what has happened, should have been announced in advance.
126470. Tom Dayton at 11:44 AM on 22 November 2009
        The albedo effect
        Henry Pool wrote "I have clearly proven to you with my experiment no.1 that global warming is most probably caused by the increase in energy released in the atmosphere due to human activties." Henry, if you demand more detailed evidence than the quick quantification that Steve L quickly provided you, you can look for free at the presentation by Flanner, et al. (2009), "Integrating Anthropogenic Heat Flux With Global Climate Models." Even more detail is in the companion journal article: Flanner, M. G. (2009), Integrating anthropogenic heat flux with global climate models, Geophys. Res. Lett., 36, L02801, doi:10.1029/2008GL036465. Averaged over the entire globe's surface, anthropogenic heat flux contributed only 0.028 watts/meter^2 in 2005. That's a tiny fraction of the forcing from CO2, which is 2.66 watts/meter^2.
126471. dhogaza at 09:56 AM on 22 November 2009
        What do the hacked CRU emails tell us?
        

        Um, the most important word in the email is "hide". If the decline were actually not real(say if it were a statistical artifact), it would not need to be hidden.

        The decline isn't real. The instrumental temperature record shows that it isn't real. Global temps over the last fifty years have not declined, they've increased, despite the tree-ring data. So in essence what's happening here is an attempt to graph out what scientists believe to be the best reconstruction of past to present temps they can. Gavin Schmidt agrees that the graph created for the WMO brochure should've been more comprehensively labelled, but this has nothing to do with the science. Mann explained exactly what he did and why he did it in his Nature article. All out in the open, nothing "hidden". The divergence problem is real. As John mentions in his top post, it's been discussed a lot in the literature, and is an area of active research. Denialists - Jeff Id currently is perhaps the most vehement in this view - claim that tree ring proxies can't accurately reflect temperature at all. This is bull. We know that properly situated trees are sensitive to temperature changes due to extensive work into plant (including tree) physiology (and, remember, trees are a valuable agricultural crop so most of this research has had nothing to do with the climate change debate). We also know it is bull because such reconstructions closely match other proxy reconstructions. Also, not all dendro datasets show the divergence problem.

        Is it right to say, then, that the decline needed to be 'hidden' because it was in the case referred to shown by the tree-ring proxy data, which, given your comments about sensitivity, would have been a distortion to include in that case?

        I'd say it's simpler - the decline shown by the tree-ring proxy data over recent decades can't be real because the instrumental record shows it's not real.
126472. SNRatio at 09:23 AM on 22 November 2009
        High CO2 in the past, Part 2
        #25 DrMike I think you may have misinterpreted the physics a little here: Forcing doesn't "explain away", anything - the basic forcing is relatively well established, and the sum of solar + C02 forcing is comparable to what we are entering into now. Not very much more, not very much less. The feedbacks are not entirely independent of the forcings, but as a first approximation we can assume they are. Therefore, very much higher CO2 in the past is, roughly, balanced by a somewhat weaker sun. The general picture strongly supports the mainstream theory here. Because we lack the necessary data, we can't, now, in any conclusive way use perceived anomalies in the distant past, like the glaciation/lack thereof at a given level of forcing, to refute current theories. And as long as those theories involve feedbacks as the dominating mechanism, we may face principal limitations in what we may prove with some rigor, because of the complexities. On the other hand, we can obtain crude estimates of long-term averages, and, if I am not quite mistaken, these estimates indicate, in general, significant positive feedback. I think this is a reason why the paleoclimatic record is little brought up by people denying AGW: Their claims are not well supported by the available data, and this tends to get worse over time.. I can well understand that you are not convinced, but you have to make a detailed argument building on best available estimates to get much further. As for the main AGW issues, they will be settled, conclusively, over a few decades from now by the large-scale experiment mankind performs on earth, regardless of any unexplained anomalies of the past. I also find your categorization "climate change advocates" a little funny, as long as climate, as defined by long-time trends, (periods longer than combined sun and ocean cycle lengths) is clearly changing. It will, in fact, take quite a lot of cooling to even out the long-time trends so much as to be able to speak of "no change". Because short-time fluctuations of most parameters are, mostly, several times larger than changes by trend, statistics calculated from observations over shorter periods are, generally, unstable and therefore of little value. There is, at present, no question about climate change. The main questions are, how fast, and is it transient or more stable? What are the reasons? How big is the anthropogenic component, and what constitutes it?
126473. Steve L at 09:18 AM on 22 November 2009
        An overview of glacier trends
        Thanks Chris. You're right, my question might have been better here.
126474. Steve L at 08:57 AM on 22 November 2009
        The albedo effect
        Henry, here is a quick quantification of direct anthropogenic heat production: http://www.realclimate.org/index.php/archives/2009/10/an-open-letter-to-steve-levitt/ Direct anthropogenic heating, even under assumptions favorable to it as an hypothesis, explains very little of the observed energy content increase of the Earth. The Arctic (and other low human density and activity places like mountain tops) is warming much faster than other places, nighttime is warming faster than daytime despite less energy burning at night.... What does this tell you?
126475. SNRatio at 08:31 AM on 22 November 2009
        High CO2 in the past, Part 2
        #23 drmike I'm no expert in this, but as far as I can see, the low temporal resolution in the CO2 record may hide "shorter time" changes, like the ordovician episode mentioned in the posting. Such changes may also account for de-glaciations. There are a number of references cited in the above comments, I guess they may be a good place to look for (partial) explanations. I also wonder if the feedbacks have been constant over time. Changing feedbacks may explain a lot - remember that the actual warming effect is forcing + feedback, with feedbacks seemingly much larger than forcings, but variable. There's where the correlation you mentioned kicks in, the relationship between CO2 and temperature is "non-deterministic". And while we may estimate the forcings with some certainty, actual feedbacks depend on a lot of factors that we may never know for the distant past. Without knowing more about details, I think it may be difficult to use the known record for refutations of the type: "X amount of forcing did not result in Y amount of glaciation, therefore the theory is disproved". We may have rather delicate balances here, think of a dynamic system with more than one attractor. Just my speculation :-)
126476. Darren Lewin-Hill at 08:29 AM on 22 November 2009
        What do the hacked CRU emails tell us?
        Thanks for this post, John. Is it right to say, then, that the decline needed to be 'hidden' because it was in the case referred to shown by the tree-ring proxy data, which, given your comments about sensitivity, would have been a distortion to include in that case? If so, bad choice of word (though it wasn't being chosen for publication), but no problem for climate science. I, and not doubt other lay readers, really appreciate the clarity of your writing here - Thanks.
126477. John Cook at 08:14 AM on 22 November 2009
        What do the hacked CRU emails tell us?
        A page worth reading: Newtongate: the final nail in the coffin of Renaissance and Enlightenment ‘thinking’. It looks like they've actually read through actual correspondance to, from and about Isaac Newton to find incriminating excerpts.
126478. shawnhet at 05:41 AM on 22 November 2009
        What do the hacked CRU emails tell us?
        Um, the most important word in the email is "hide". If the decline were actually not real(say if it were a statistical artifact), it would not need to be hidden. In any case, frankly, I don't think that there is much new here in terms of the scientific issues. It seems to me that anyone with a decent understanding of the issues should probably recognize 1.that tree ring reconstructions are based on some pretty shaky science and 2. that there is a pretty decent chance that recent temperature changes are not all that unprecedented(being slightly warmer than MWP perhaps). Obviously, many people have been saying for a long time that 1&2 are true and these emails give them significant validation IMO. Also, since a couple of folks have brought up the fact that the physics are still right, it bears repeating that current predictions are not based solely on physics, but also on computer simulations that parameterize atmospheric effects. Cheers, :)
126479. chris at 05:34 AM on 22 November 2009
        An overview of glacier trends
        re #26; Steve, I posted this post on the wrong thread! I've posted it also on the Greenland ice trends where it belongs (even though it sounds like it should belong on a glacier thread like this one!)
126480. chris at 05:26 AM on 22 November 2009
        An overview of Greenland ice trends
        Hi Steve, Yes, the situation with polar ice sheets and mountain glaciers must be very different. I’m no expert (I just read the papers to find out what the science shows!), but I expect that sea level rise should continue to accelerate as temperature continues to rise, since the rate of sea level rise seems to be for now related to the extent of warming above the pre-industrial temperature (e.g. see [*]). Much of this so far seems to be due to thermal expansion with some polar ice sheet contributions the latter seeming to be accelerating, and a small amount from mountain glaciers. I would have thought that the polar ice sheet contribution wouldn’t slow down for a very long time, whether or not any “catastrophic” “collapse”-type scenarios might kick in. Since polar ice sheet re-equilibration to a new forcing occurs on very slow timescales (hundreds of years; although HumanityRules doesn’t seem to like what I think is a very obvious expectation of a slow response time!), sea level rise isn’t expected to slow down for a very long time. In relation to the slow ice sheet response time, the fact that pre-industrial Holocene temperatures maxed around 8000 years ago, and sea levels were still rising from post-glacial ice sheet responses and warming-induced ocean expansion at least through 6000 years ago and possibly as late as 3000 years ago, it seems obvious that ice sheet responses (and ocean warming) have slow response times to warming forcings. As for mountain glaciers, I’m sure you’re right. There are definitely geographical contributions to glacier length and mass balance responses. According to several studies I’ve looked at there’s a strong geometrical contribution to the glacier response time (e.g. [**]), with steeper glaciers showing more rapid response times that shallow glaciers. My own feeling/guess/intuition/deduction would be that as glaciers retreated to higher and higher altitudes, the residual “rump” would become more and more difficult to melt. However, that might not be correct! Going back to your specific question I expect that sea level rise in the long term will be dominated by polar ice sheet melt, and this won’t stop for a very long time. It will continue to accelerate as the forcing increases (temperature continues to rise), and when the forcing stops rising, the ice sheets will continue to melt for many, many decades as they slowly re-equilibrate. [*] S. Rahmstorf (2007) A Semi-Empirical Approach to Projecting Future Sea-Level Rise Science 315, 368 – 370 A semi-empirical relation is presented that connects global sea-level rise to global mean surface temperature. It is proposed that, for time scales relevant to anthropogenic warming, the rate of sea-level rise is roughly proportional to the magnitude of warming above the temperatures of the pre–Industrial Age. This holds to good approximation for temperature and sea-level changes during the 20th century, with a proportionality constant of 3.4 millimeters/year per °C. When applied to future warming scenarios of the Intergovernmental Panel on Climate Change, this relationship results in a projected sea-level rise in 2100 of 0.5 to 1.4 meters above the 1990 level. [**] J. Oerlemans (2007) Estimating response times of Vadret da Morteratsch, Vadret da Palu¨ , Briksdalsbreen and Nigardsbreen from their length records Journal of Glaciology, Vol. 53, No. 182 Abstract: Length records of two pairs of glaciers are used to reconstruct the equilibrium-line altitude (ELA) and to estimate glacier response times. The method is based on the assumption that neighbouring glaciers should be subject to the same climatic forcing, and that differences in the length records are thus caused by differences in response times and climate sensitivities. By means of a control method, in which the difference between the reconstructed histories of the ELA is minimized, realistic response times are found. The pairs of glaciers studied are: (i) Vadret da Morteratsch and Vadret da Palu¨ in the Swiss Alps and (ii) Briksdalsbreen and Nigardsbreen in southern Norway. In both cases the reconstructed ELA histories of the individual glaciers are very similar, in spite of the large differences in the length records. Short e-folding response times are found for the steep glaciers: 4.4 years for Vadret da Palii, 5.0 years for Briksdalsbreen. For the larger glaciers with a more gentle slope the response times are substantially larger: 33.0 years for Vadret da Morteratsch, 34.8 years for Nigardsbreen.
126481. chris at 05:25 AM on 22 November 2009
        An overview of glacier trends
        Hi Steve, Yes, the situation with polar ice sheets and mountain glaciers must be very different. I’m no expert (I just read the papers to find out what the science shows!), but I expect that sea level rise should continue to accelerate as temperature continues to rise, since the rate of sea level rise seems to be for now related to the extent of warming above the pre-industrial temperature (e.g. see [*]). Much of this so far seems to be due to thermal expansion with some polar ice sheet contributions the latter seeming to be accelerating, and a small amount from mountain glaciers. I would have thought that the polar ice sheet contribution wouldn’t slow down for a very long time, whether or not any “catastrophic” “collapse”-type scenarios might kick in. Since polar ice sheet re-equilibration to a new forcing occurs on very slow timescales (hundreds of years; although HumanityRules doesn’t seem to like what I think is a very obvious expectation of a slow response time!), sea level rise isn’t expected to slow down for a very long time. In relation to the slow ice sheet response time, the fact that pre-industrial Holocene temperatures maxed around 8000 years ago, and sea levels were still rising from post-glacial ice sheet responses and warming-induced ocean expansion at least through 6000 years ago and possibly as late as 3000 years ago, it seems obvious that ice sheet responses (and ocean warming) have slow response times to warming forcings. As for mountain glaciers, I’m sure you’re right. There are definitely geographical contributions to glacier length and mass balance responses. According to several studies I’ve looked at there’s a strong geometrical contribution to the glacier response time (e.g. [**]), with steeper glaciers showing more rapid response times that shallow glaciers. My own feeling/guess/intuition/deduction would be that as glaciers retreated to higher and higher altitudes, the residual “rump” would become more and more difficult to melt. However, that might not be correct! Going back to your specific question I expect that sea level rise in the long term will be dominated by polar ice sheet melt, and this won’t stop for a very long time. It will continue to accelerate as the forcing increases (temperature continues to rise), and when the forcing stops rising, the ice sheets will continue to melt for many, many decades as they slowly re-equilibrate. [*] S. Rahmstorf (2007) A Semi-Empirical Approach to Projecting Future Sea-Level Rise Science 315, 368 – 370 A semi-empirical relation is presented that connects global sea-level rise to global mean surface temperature. It is proposed that, for time scales relevant to anthropogenic warming, the rate of sea-level rise is roughly proportional to the magnitude of warming above the temperatures of the pre–Industrial Age. This holds to good approximation for temperature and sea-level changes during the 20th century, with a proportionality constant of 3.4 millimeters/year per °C. When applied to future warming scenarios of the Intergovernmental Panel on Climate Change, this relationship results in a projected sea-level rise in 2100 of 0.5 to 1.4 meters above the 1990 level. [**] J. Oerlemans (2007) Estimating response times of Vadret da Morteratsch, Vadret da Palu¨, Briksdalsbreen and Nigardsbreen from their length records Journal of Glaciology, Vol. 53, No. 182 Abstract: Length records of two pairs of glaciers are used to reconstruct the equilibrium-line altitude (ELA) and to estimate glacier response times. The method is based on the assumption that neighbouring glaciers should be subject to the same climatic forcing, and that differences in the length records are thus caused by differences in response times and climate sensitivities. By means of a control method, in which the difference between the reconstructed histories of the ELA is minimized, realistic response times are found. The pairs of glaciers studied are: (i) Vadret da Morteratsch and Vadret da Palu¨ in the Swiss Alps and (ii) Briksdalsbreen and Nigardsbreen in southern Norway. In both cases the reconstructed ELA histories of the individual glaciers are very similar, in spite of the large differences in the length records. Short e-folding response times are found for the steep glaciers: 4.4 years for Vadret da Palii, 5.0 years for Briksdalsbreen. For the larger glaciers with a more gentle slope the response times are substantially larger: 33.0 years for Vadret da Morteratsch, 34.8 years for Nigardsbreen.
126482. DrMike at 05:18 AM on 22 November 2009
        High CO2 in the past, Part 2
        Thanks for the response. While I have no issue with the idea that hidden complexities in the climate feedback systems may explain apparent inconsistencies, I don't think that one needs to establish the refutation you outlined: "X amount...". On the contrary, it seems that the burden of proof relative to this skeptic argument lies with with the climate change advocates. I don't think the forcing argument alone works, considering the presence of the aforementioned hidden complexities in the feedback systems. Since the forcing argument is primary to explaining away very high CO2 levels in the past, I don't see how one can walk away from this issue satisfied. I'm not. And, I think it is the most powerful argument the skeptics have posed to date. I hope I interpreted your answer correctly. Thanks again.
126483. SNRatio at 05:00 AM on 22 November 2009
        High CO2 in the past, Part 2
        #23 drmike I'm no expert in this, but as far as I can see, the low temporal resolution in the CO2 record may hide "shorter time" changes, like the ordovician episode mentioned in the posting. Such changes may also account for de-glaciations. There are a number of references cited in the above comments, I guess they may be a good place to look for (partial) explanations. I also wonder if the feedbacks have been constant over time. Changing feedbacks may explain a lot - remember that the actual warming effect is forcing + feedback, with feedbacks seemingly much larger than forcings, but variable. There's where the correlation you mentioned kicks in, the relationship between CO2 and temperature is "non-deterministic". And while we may estimate the forcings with some certainty, actual feedbacks depend on a lot of factors that we may never know for the distant past. Without knowing more about details, I think it may be difficult to use the known record for refutations of the type: "X amount of forcing did not result in Y amount of glaciation, therefore the theory is disproved". We may have rather delicate balances here, think of a dynamic system with more than one attractor. Just my speculation :-)
126484. pdt at 04:13 AM on 22 November 2009
        What do the hacked CRU emails tell us?
        This just reconfirms that scientists are human beings. No surprise there I hope.
126485. ejo60 at 04:00 AM on 22 November 2009
        What do the hacked CRU emails tell us?
        @Philippe: Scientists do often fight like little children, it is well known and unfortunately now also publicly exposed. What does matter is, is the physics right, and can somebody who is not involved in the discussion come to the same conclusion within the same boundary conditions of course. If that is not the case then all bells and whistles should go off, but I don't expect this to happen with the Hockey stick, because Mann's finding was independently confirmed already.
126486. Philippe Chantreau at 03:34 AM on 22 November 2009
        What do the hacked CRU emails tell us?
        This is pathetic. "Skeptics" have declared that anything goes. It would be of course equally low to hack McIntyre or Watts' personal e-mails, and those of the think tanks and industries hostile to action. Yet I can't help to think it would only be equitable to have all their dirt posted on the internet as well. Just to see who's really more dishonest in the whole "debate."
126487. Tom Dayton at 03:33 AM on 22 November 2009
        The albedo effect
        Henry Pool, your prediction about the outcome of your proposed experiments--that the amount of CO2 in the vessel will make no difference--is not a result of your experiment. Science requires actual measurement, not merely thought experiments. Your prediction is incorrect, as has been measured (not merely imagined) since the 1800s. As Riccardo informed you already, Tyndall did it in the 1800s, and it has been repeated thousands of times since, with the same result, though with increasing precision and accuracy. It's even done by students 11 to 14 years old! Here is one set of instructions with photos and a graph of results. Here is another. And here is a worksheet from a different country, with better diagrams to help students set up and run the experiment. You can easily do this experiment in your kitchen so you have empirical results instead of your guesses. The Physics Forum thread "Need Help: Can You Model CO2 as a Greenhouse Gas?" has descriptions, and links to other descriptions, of several versions that use plastic soda bottles or bags instead of glass flasks. That same discussion thread discusses solutions to problems you might encounter in running your experiment. That thread addresses this topic only until page 4, then drifts away for a while, but comes back to the topic on page 9 but no further than page 9. Of course, scientists have not done such crude versions of the experiment since the 1800s. Instead they have done far more sophisticated experiments. Those are done by college students and graduate students hundreds of times every year, always with the same result of CO2 slowing the escape of infrared radiation. The most recent experiments done by professional scientists rather than students are published in the peer-reviewed scientific literature. Some of the most recent examples of those are listed in the AGW Observer's site: Measurements in laboratories are listed in one section, and measurements in the atmosphere are listed in another section.
126488. ejo60 at 03:29 AM on 22 November 2009
        What do the hacked CRU emails tell us?
        @realclimate I left the following message: It is true that hackers are a problem nowadays, my linux box reports many break in attempts, but to the best of my knowledge nobody ever passed the defense lines. The stolen CRU data which is now publicly made available causes quite some trolling on the internet. But so far I’ve not seen anything coming close to disclosing global warming as a scam or whatever is claimed by the trolls and the global warming deniers. Meanwhile the consequences of global warming continue to become available and they have absolutely nothing in common with the CRU data center. Greenland is for instance showing accelerated melting, it is picked up as a gravity feature, as shown last week in Science. And such results will fill the peer-reviewed journals for the next coming years. Let me add: The interesting point we will hopefully learn is whether there is a bias in science research, which is a fundamental problem not resolved by peer review. One of my students suggested an improvement therefore to the peer review system, he said, lets make the system double blind, meaning that a reviewer doesn't know who the author is and the other way around also, that authors don't know who reviewers are (which is actually my default mode as reviewer).
126489. HumanityRules at 02:10 AM on 22 November 2009
        What do the hacked CRU emails tell us?
        Scientists are as cynical as the rest of us so you can't read too much into personnel emails ......but....... ouch. you may think I'm a climate skeptic but really what I am is critical of individuals making too much of their research and more importantly media and politicians blowing situations out of proportion. Nobody wants to see science smeared by careerists. There's popcorn downstairs I better go and get it!!
126490. John Cross at 01:51 AM on 22 November 2009
        What do the hacked CRU emails tell us?
        As I posted earlier on another site, let me know when they find the e-mails that show our understanding of the physics is wrong. Until then this is just dirt. However it is amusing to see what is being quoted as the "smoking gun". For example this:

        “Since the IPCC makes it quite clear that there are substantial grounds for concern about climate change, is it not partially the responsibility of climate science to make sure only satisfactorily peer-reviewed science appears in scientific publications? – and to refute any inadequately reviewed and wrong articles that do make their way through the peer review process?”

        is being offered as "Evidence of an organized subversion of the peer review process". Also Soon (2003) is being dragged up as evidence of blacklisting of scientific journals. I would have though they would have wanted Soon 2003 to remain buried as long as possible. My recommendation, sit back, grab some popcorn and watch as this unfolds. Regards, John
126491. DrMike at 01:32 AM on 22 November 2009
        High CO2 in the past, Part 2
        Thanks, I'll take a look. However, could someone address the specific questions I ask about the seemingly inconsistent forcing numbers at which glaciation initiates. If the forcing numbers are correct (I'll look deeper at the basic idea), then how does one explain the initiation of glaciation at both high and low forcing values. Also, no glaciation at the minimum of the forcing value? If the forcing calculations were reliable, It don't think anyone would have to explain away 10s of thousands of years in the permian period, where the forcing clearly strikes a minimum value, without coincident glaciation. Also no explanation regarding "thresholds" would be required for the initiation and perpetuation of a glaciation near the end of the Paleogene period, when the estimated forcing was near a local maximum above +4. Threshold reasoning often creates a thin argument, in my experience. My doubt in the basis of the forcing argument clearly does not come from my skepticism of basic physics, in which I have faith, rather my doubt stems from the lack of clear and consistent evidence showing that the estimated forcing numbers lead to glaciation and de-glaciation (or melting). Thanks for the response.
126492. Riccardo at 22:59 PM on 21 November 2009
        Is Pacific Decadal Oscillation the Smoking Gun?
        Marcus, PDO and ENSO share a surprising similar sea surface temperature and surface wind field patterns in the Pacific Ocean. Being independent in the respective cycles, this fact seems to point to a common general response to different forcing or variability; but neither one controls climate, the reverse might be true.
126493. SNRatio at 21:39 PM on 21 November 2009
        High CO2 in the past, Part 2
        #21 DrMike, you may want to read up on the basic physics here, as the problem you perceive completely disappears upon analysis. Chris Colose has an excellent introduction: http://chriscolose.wordpress.com/2009/10/08/re-visiting-cff/ Maybe you can come back here after having penetrated the subject a bit. The paleoclimatic record seems to confirm that the basic physics concepts are, basically, correct. If you can show that the theory does not fit with the data, that would be very interesting - but you have to apply the theory correctly to do that. Just a hint: CO2 radiative forcing goes with the logarithm of the concentration ratios, so ln(5600/280)=ln(20)=3. With no positive feedback, the first order approximation to the temperature rise from 56 vs 280 ppm CO2 is 3*5.35*0.27=4.3 deg C. Feedbacks will in most circumstances make the effects larger, but that is counterbalanced by a far weaker sun than today.
126494. Riccardo at 19:30 PM on 21 November 2009
        The albedo effect
        Henry Pool, i don't see any proof of whatever but just what you immagine would happen. It's offtpic in this post on albedo talking on attribution of global warming, but anyways, whenever you immagine a possible cause you should quantify it to confirm that you get reasonable numbers. Anyone could say to not have a swim because the ocean would warm ...
126495. Marcus at 18:41 PM on 21 November 2009
        Is Pacific Decadal Oscillation the Smoking Gun?
        Here's the thing I keep coming back to-Decadal Oscillations have been going on since time out of mind, yet we're supposed to believe that *suddenly* they're generating a 60-year long warming trend. If so, what has changed in the DO's to make them do this? The oceans might store & distribute heat but, last I checked, they couldn't create that heat out of nothing. Isn't it possible that atmospheric warming is driving changes in the Decadal Oscillations, rather than the other way around? At days end, over the last 60 years, we've been seeing the fastest rise in global temperatures in more than 12,000 years-& the only thing which has changed significantly in the same period of time is the atmospheric concentration of greenhouse gases. Perhaps that's a coincidence, but Occam's Razor suggests otherwise.
126496. Henry Pool at 18:40 PM on 21 November 2009
        The albedo effect
        To make it even more interesting you could do a third experiment at the CO2 concentration as it was 50 years ago, i.e. 280 ppm. But let's face it. I don't expect either the odd 280 nor the current 350 ppm's CO2 to make any difference on the heat retention inside that vessel. Maybe if you filled the vessel up to 50 or 100% CO2 would you see some influence on the heat retention. But that has been my point from the beginning: you must do your testing in the relevant concentration range. So what is my conclusion? I have clearly proven to you with my experiment no.1 that global warming is most probably caused by the increase in energy released in the atmosphere due to human activties. Think of all the warfare in the past,explosions of atomic boms in the Indian ocean, oil and gas fields burning, etc. Also, living in Africa, I would say that people living without electricity do not necessarily cause less energy to be released. To cook and to stay warm they just burn anything that they can find, and you cannot blame them. If global warming is indeed not caused by carbon dioxide you may feel a little less guilty about driving your car. But don’t open the champagne bottles just yet. The fight against global warming might in fact get more difficult. If global warming = us, we would have to reduce the total energy output per person. We have to steal energy from nature. (Wind, gravity, tides, solar etc.). Carbon emissions would not be green. Nuclear energy would not be green. Hydrogen and oxygen combustion (rocket fuel) would also not be green. In fact, in that case we will have to re-visit the whole global warming debate, for example in the case of sending rockets out to space: will the burden of all that energy released in the atmosphere by placing that satellite in orbit, result in similar savings in energy on earth?
126497. Marcus at 18:27 PM on 21 November 2009
        Is Pacific Decadal Oscillation the Smoking Gun?
        The only reason the UAH data diverges from all the rest is because the UAH was relying on Diurnal (day & night) data-which resulted in a lower temperature anomaly. Other researchers have corrected for this error, & the resulting data set is now virtually identical to that of GISS, RSS & HadCRU datasets.
126498. DrMike at 17:45 PM on 21 November 2009
        High CO2 in the past, Part 2
        Of all the discussions on this website, I think this one deserves the most attention. I think it is the thinnest defense for the climate guys, and the most powerful argument for the skeptics. What I mean to say is that if there were no explanation for why CO2 could be in the thousands of PPM with no concomitant substantial temperature rise, it would be game over for the climate guys. My initial inclination when I look at the plot in Figure 2 is to sarcastically say "How Convenient" it is that the radiative forcing numbers work out to be what is presented. I'll hold that jab for a moment though. The burden of proof is clearly on the climate guys on this one. I have some questions. 1. Why do glaciations initiate at both ends of the radiative forcing timeline(+4 at the end of the Paleogene, and -4 in the middle of the caroniferous timeframes)? 2. Why is there no glaciation at the minimum in the forcing timeline (middle permian)? As far as I can tell, the concept of radiative forcing is really just a mathematical fit of the correlation between T and CO2, without substantive quantitative causal evidence. There is certainly reason to believe in a qualitative causal relationship between CO2 and T, but to quantify the causal relationship based on a correlation and physical inference is a leap.
126499. DrMike at 17:14 PM on 21 November 2009
        Working out climate sensitivity
        I'm trying to get this all straight. So, we look back at T and CO2 correlations over time. Using the correlation relationships, recognizing that the correlations are confounded by obvious additional factors, we build probability distributions to estimate the likely correlation between just CO2 and T. I'm OK with that. Seems pretty straight forward. But stay with me here. Now, in a separate conversation we look into some principles from basic physics describing how CO2 molecules interact with IR. For instance, we know that CO2 absorbs well at characteristic frequencies, like most similar molecules. I'm OK with that too, straight forward stuff. But stay with me here. So there is a correlation between T and CO2, we can describe it with some set of probability distributions, AND, we know that CO2 interacts with IR radiation, or heat, which is also correlated with temperature. So, here is where I get lost. All of a sudden, because we know that Temperature is a covariate of IR radiation, and that Temperature is also a covariate of atmospheric CO2 concentration, we somehow get causality or "Forcing". Transitive causality in atomospheric science. Maybe for some it's "common sense", but with the myriad complex variables comprising atomospheric events, "common sense" doesn't cut it. In addition, the concept that there is a single "forcing" number contained within the probability distributions is offensive to my sensibilities as a scientist. IF..., and this is a big IF in my interpretation, this so-called CO2 forcing does occur, isn't it highly likely that it would vary in a more complex manner than a simple logarithmic function. I am new to this topic in the last year or so, and only recently have I begun to read the foundational work in detail. I am finding it really hard to swallow.
126500. Steve L at 05:33 AM on 21 November 2009
        Record high temperatures versus record lows
        I don't have the data, but I'm guessing "no, the upper tail is getting shorter relative to the mean" from the fact that new record highs aren't yet exceeding the null expectation. Perhaps the distribution will continue to get less leptokurtic, but it's because the bulk of the temperatures is creeping up and eventually we'll see red dots higher than the line more and more often. I think this is interesting because the expectation of "more extreme weather" that comes with AGW might be interpreted as a flattening of the density function. I would be curious to learn whether or not the data as summarized above are actually relevant to the notion that weather will become more extreme. Is there a contradiction or, if not, what is the disconnect?

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