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Comments 126401 to 126450:

126401. 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.
126402. 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 OK, then I would say that Newtonian ethics is much more outdated than Newtonian mechanics :-) The political impact will be much bigger, but mostly short term.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.
126403. 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.
126404. 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.
126405. 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?
126406. 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.
126407. 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?
126408. 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 :-)
126409. 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.
126410. 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.
126411. 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, :)
126412. 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!)
126413. 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.
126414. 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.
126415. 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.
126416. 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 :-)
126417. 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.
126418. 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.
126419. 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."
126420. 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.
126421. 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).
126422. 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!!
126423. 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
126424. 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.
126425. 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.
126426. 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.
126427. 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 ...
126428. 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.
126429. 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?
126430. 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.
126431. 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.
126432. 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.
126433. 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?
126434. Albatross at 04:51 AM on 21 November 2009
        Record high temperatures versus record lows
        SeveL, thanks. You described what I was picturing, although has the tail for the max. temps not also become longer? Maybe someone who has the raw data could generate the PDF for the temperature data. I could try to do so, but don't know where to source the data.
126435. Riccardo at 04:48 AM on 21 November 2009
        The albedo effect
        Henry Pool, given that you think that absorption is a confusing word and that the missing intensity at some wavelgths at the earth surface are an indication of higher reflectivity, belive me, i can't anticipate what your conclusions might be.
126436. Henry Pool at 03:33 AM on 21 November 2009
        The albedo effect
        Riccardo, you have fallen in my trap. If you know the answers coming from my experiment, and if you say that the earth is a greenhouse then......what is my conclusion????
126437. Steve L at 03:05 AM on 21 November 2009
        Record high temperatures versus record lows
        I think I can picture the probability function changes described by the study (based on 24 hour periods, each standardized to the mean for that day of the year) -- the tail toward lower temperatures has shortened while the tail toward higher temperatures has stayed the same [affecting the kurtosis] and the bulk of the data have shifted slightly toward higher temperatures [affecting the skew of the distribution]. I don't know if this is what you (@19) mean. You write "rather than each day being +2C warmer" suggests that you might be talking about variance among days of the year rather than changes on a given day of the year. That would be quite a different way of looking at the data.
126438. Riccardo at 01:11 AM on 21 November 2009
        The albedo effect
        Tyndall in 1859 did this kind of eeperiment for the first time. Since then it has been reproduced by many other. If each time we have to repeate two centuries of science, we'd be stuck at Galielo and Newton or maybe even Archimedes.
126439. Henry Pool at 00:27 AM on 21 November 2009
        The albedo effect
        Really, we are going around in circles. Why not first answer me on 127? If I look at those graphs then there is really only a very small corner of earth radiation cut off by the CO2 at 14 um. It is not the surface area of the absorptions that is important, it is the width in um of the waveband lengths where absorption takes place (even the slightest absorption). This is where reflection (or scattering) takes place. Anyway; I have thought of the following simple experiment to settle this matter. Do you think it would work? If not, why not? Experiment 1 We have a glass vessel, about 1000 liters, flushed and filled with 80% nitrogen and 20% oxygen, representing the earth and its atmosphere at the beginning. We have a probe on the side, in the middle, connected to a thermocouple and a temperature recorder. We have a large heating element in the middle of the vessel. The vessel is closed from the outside. The outside temperature and humidity is kept constant, at all times. A measured amount of energy is released into the vessel. The resulting increase of the temperature in the vessel is recorded until it falls back to the base line. The area below the curve is measured. The measurements are repeated until a constant result can be reported. (A) We now double the amount of energy released into the vessel, this increase representing the doubling of energy released by human activity on earth from 3.5 billion people in 1960 to 7 billion people in 2009. The area below the curve is measured. The measurements are repeated until a constant result can be reported. (B) In the case of this first experiment, the result is predictable i.e. if you double the amount of energy released in a vessel you should find close to a doubling of the area under your graph. This already proves that Henry’s theory rather than a 25% increase in carbon dioxide may have some bearing on global warming. (For the time being Henry’s theory is still that global warming is caused by people releasing energy when flying, moving, cooking or just wanting to stay warm or cold) Experiment 2 Experiment 2 is exactly the same as experiment 1, but now the vessel is filled with air, which includes all 350 ppm or so carbon dioxide currently available in 2009 air. The results are C en D. What would be interesting for me to know is the difference between A and C and between B and D – in other words: if we release similar amounts of energy into the vessel, what effects, if any, does the carbon dioxide and the other gases present in air have on temperature retention inside the vessel?
126440. Albatross at 16:33 PM on 20 November 2009
        Record high temperatures versus record lows
        Interesting study, got Anthony Watts all steamed up. I have not looked into the specifics, but I was wondering if anyone has determined whether or not there has been a statistically significant shift in the probablility distribution function/s (PDF)for the min. and max. temperatures? It is my recollection that AGW is going to manifest itself (or rather already has) in the shift of the PDF of temperatures, especially the tails, rather than each day being +2C warmer, for example, as many people tend to think. Anyhow, a PDF analysis might be more robust and insightful than the data contained the figures here.
126441. ejo60 at 14:16 PM on 20 November 2009
        Why is Greenland's ice loss accelerating?
        @RSVP: The mixing of a fresh water pulse is described in a paper written by Detlef Stammer last year in JGR. To summarize, it takes a while before it is mixed and it mixes globally, not locally at suggested here. We are talking about time scales of 100 years or so.
126442. iskepticaluser at 13:33 PM on 20 November 2009
        Increasing CO2 has little to no effect
        re comment 1 (HumanityRules), referring to apparent increases in radiation in the 800-1000 part of the spectrum in the Harries paper (the full version of which you can find through Google Scholar): on page two, 2nd column, that paper does indeed offer a potential explanation, viz. incompletely-cleared artifacts in the data (due to ice-cloud absorption). Considering the study is the first of its kind, its finding of reduced radiation precisely in the wavelengths associated with increased GHG concentrations remains remains highly suggestive, no?
126443. Alexandre at 10:21 AM on 20 November 2009
        Record high temperatures versus record lows
        One detail I noticed on the UCAR page: there´s a special box for journalists. This is great. Communication of scientists with the press shoul be smoothed as much as possible.
126444. Riccardo at 08:25 AM on 20 November 2009
        The albedo effect
        Henry Pool, it's not me that's eventually wrong, it's two hundreds years of physics of radiation. Instead, for you it's correct that the radiation missing at the earth surface does not show up in the reflected spectrum and it's not absorbed (absorption, for you, is the word that confuses people). Then not even energy is conserved in the process ...
126445. Tom Dayton at 06:57 AM on 20 November 2009
        The albedo effect
        Henry, you wrote "I did try to look at that paper but it is something to do with testing in high pressures and high CO2 concentrations which cannot be related to what we are talking about here." Henry, you need to actually read the posts, not just skim them. I pointed you to not just that article, but I went to the trouble to tell you specifically which figure to look at in that article, and I explained specifically how it relates to "what we are talking about here." CO2's Raleigh scattering is inconsequentially small at its partial pressure in Earth's atmosphere, and more importantly any increases in its partial pressure (concentration) in the range of even the most horribly tremendous human-or-natural-caused releases would leave its Raleigh scattering still inconsequential. Look at that figure in that article.
126446. Steve L at 03:36 AM on 20 November 2009
        Record high temperatures versus record lows
        RSVP: 1, actually there are probably fewer blue dots in the summer too (the news release attributes the pattern to warmer nighttime temperatures). 3, agreed, but I think self-interest is only one of several factors involved (religiosity, propensity to listen to talk radio, generally being set in one's ways, etc). Nobody has either agreed or disagreed with me regarding whether ratios or percentages are a better way to summarize the information. I'm surprised because I thought that might be the most substantive thing I've written in a while.
126447. cbrock at 03:25 AM on 20 November 2009
        Record high temperatures versus record lows
        John @15, to stay sidetracked (sorry John C.), my father is in the "extractive industries" field--a professor of petroleum accounting at a Texas university, but having a physics background--and is constantly bombarded with the usual Fred Singer quotes from his colleagues. The SkepticalScience site has really been great at supplying him with ready responses to these sorts of comments. He's learned a lot and has a much deeper understanding of the issues. So great thanks to John Cook for taking all the time and energy to sort through the science and distill complex findings into clear and succinct summaries that the general public can understand. And for maintaining a site that is free of political ranting! I've not found a better site for this, and I've looked quite a bit.
126448. Mizimi at 02:33 AM on 20 November 2009
        What does past climate change tell us?
        Chris# I think you may have typo'd here... "and the Greenland ice cap is likely committed to melt at atmospheric CO2 equivalents above around 280 ppm" or are you really letting us off the hook?
126449. Henry Pool at 02:25 AM on 20 November 2009
        The albedo effect
        @Tom on 44, I did try to look at that paper but it is something to do with testing in high pressures and high CO2 concentrations which cannot be related to what we are talking about here. I think Riccardo is wrong, he does not understand what the gases are doing in the atmosphere when you see the sun's radiation on top of earth (before the atmosphere) and at sea level (below the atmosphere). This has been measured many times. Look at your own doc. Surely that difference (the radiation reflected), is what makes the bulk of earth's albedo? If you look at the sun's solar radiation spectrum then you can see that a bulk of UV is cut off, especially where the sun's curve is the biggest.
126450. Tom Dayton at 01:49 AM on 20 November 2009
        The albedo effect
        Henry, when water snow falls it traps air in between the snowflakes. Accumulating weight of the snow on top compresses the flakes but does not squeeze out all the air. So the ice cores contain lots of trapped air, including CO2.

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