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Comments 108451 to 108500:

  1. New temperature reconstruction vindicates ...
    johnd... I think I'm going to leave this one alone. It would be off topic for this thread and an issue that has long been put to rest as well. If you wish to rehash this one I would suggest this thread.
  2. New temperature reconstruction vindicates ...
    Rob Honeycutt at 06:49 AM, yes, those based on tree ring proxies being a prime example. Perhaps you can identify those reconstructions that are tracking recent instrumental records to date.
  3. New temperature reconstruction vindicates ...
    Rob @56, I think he may be trying to make a straw man argument about the divergence problem in some of the dendro chronologies from 1960 onwards.
  4. The Phony War: Lies, Damn Lies and the IPCC
    "Of course not. Your severe bias agaisnt AGW theory won't allow you to believe otherwise." "bias agaisnt AGW theory"? I haven't written anything about radiative forcing. All I'm doing is pointing out that the extent of a warming rate is low as declared by the IPCC and by daily, annual, and millenial scales of change, not particularly significant. I would gladly like to see any evidence you can provide otherwise.
  5. New temperature reconstruction vindicates ...
    Could someone direct me to an image that shows temps from 0-2100 i.e reconstruction plus IPCC estimates.
  6. New temperature reconstruction vindicates ...
    johnd... Are you suggesting the reconstructions don't track the instrumental record?
  7. Blog review of scientific coherence
    @Argus, post 25 You are missing the point here. Nowhere in the article the claim is made that a coherent theory is automatically a correct theory. Of course a coherent theory CAN be wrong. What the article states however is that an incoherent theory cannot be correct. This is not an article about the correctness of AGW, it is an article about how skeptic theories can be proved to be wrong, if they are internally incoherent.
  8. Positive feedback means runaway warming
    It illustrates a mathematical fact that is irrelevant to the action of the fast feedbacks, which are what the introduction suggests the article is about. So what's the point?
  9. New temperature reconstruction vindicates ...
    kdkd@54, Maybe this will help KL out (and these data only go till 2009). I have posted before, but some people seem to choose to ignore the facts: An updated figure (Fig. 21a), can be found here (pg. 48).
  10. New temperature reconstruction vindicates ...
    KL #43: Oh, and all the temp charts in this thread seem to stop at year 2000 - missing the last 10 years of flattening at a time when claimed AGW forcing is 'the highest decade in history'. In a sense I can't believe that you're still peddling this misinformation. Can you explain how the fact that the decade 2000-2010 is the warmest decade on record is consistent with your assertion please? In fact, I think I've asked you that question before; you've never provided a satisfactory answer (you may have repeatedly ignored the question), and yet still wheel out the same old poorly thought out repetitive rubbish without justification.
  11. Blog review of scientific coherence
    HR, your post @19 is OT, and so is this. Just for balance, here is their entire abstract. Pay close attention to the last sentence of their abstract: "While the IMP [internal multidecadal pattern] can contribute significantly to trends for periods of 30 years or less, it cannot account for the 0.8°C warming trend that has been observed in the twentieth century spatially averaged SST." So, internal variability can explain some of the changes in global SSTs on a short-time scale, but not the underlying long-term warming trend. Nothing new there, researchers are well aware of the role of internal climate modes in modulating global temperatures. And SS does not attribute all of the observed warming to higher GHGs as you state HR. Instead of arm waving please provide a link to where this is stated, or better still go and argue on a relevant thread. I can't wait to see how WUWT "presents" these results.
  12. Blog review of scientific coherence
    Philippe Chantreau It's nice for a skeptic to acknowldedge the existence of that acceleration, when so many are saying that it's cooling, = = = = = = = = = = = = = = = = There are many skeptics who acknowledge this, especialy among the luke warmers.
  13. New temperature reconstruction vindicates ...
    Rob Honeycutt at 05:40 AM, on the other hand, unless the reconstructions track the instrumental data, then the assumptions made to enable the reconstruction have not been validated. The whole purpose I believe is that recent data should validate the proxy data.
  14. Blog review of scientific coherence
    Stephan, the use of the sheep analogy is a very very poor choice, though it may appeal to some, and that in itself may be telling. Those who are aware of how free markets work will say that in fact the person who offered that advice quite conceivably could be someone in touch with the real world. It could have been advice profferred on any commodity, even gold, or shares, and whilst the bean counters sit at their desks making all manners of predictions about future price directions, more often than not it is the contrarian who buys when others are selling or vice versa, or the those who have practical experience in the real world and can see the subtle signs of change that all others cannot, that offer the best advice. The apples example could perhaps be a valid analogy, but only for those who are susceptible to attracting such advice, whilst the bloke offering the sheep advice may well have his feet firmly on the ground, but unfortunately his advice may well be rejected by those without the practical knowledge of how markets work in the real world.
  15. New temperature reconstruction vindicates ...
    fydijkstra @ 39... "The red curves in the reconstruction graphs should be omitted, because the instrumental data are not comparable to the proxy records" Wouldn't that be a case of "hiding the incline?" The whole purpose, as I understand it, to looking at these reconstructions is to compare them to current warming.
  16. Philippe Chantreau at 05:39 AM on 30 September 2010
    Blog review of scientific coherence
    HR says "that the acceleration in warming during 1977-2008 is a consequence of natural variability." It's nice for a skeptic to acknowldedge the existence of that acceleration, when so many are saying that it's cooling, one of the most common skeptic arguments that this site addresses.
  17. The Phony War: Lies, Damn Lies and the IPCC
    @CW: "That is certainly not true for the Arctic or even the Northern Hemisphere, probably not true for the globe." By "overall" I clearly meant global averages. "Look at the noise in the whole Holocene ( plus or minus 1 degree C ). We haven't even exceeded that." It's not very useful to look at the proxy noise to determine averages were higher during the HCO than today. This is like looking at individual temperatures today and claiming such snapshots accurately reflect global temperatures (you know, what some deniers have done because it snowed a lot in their backyard last winter?) "And as I pointed out, the mean can be meaningless, as the seasonal variation was more extreme in the HCO." Not in the Mesopotamian settlements. The difference would have been barely noticeable at 30 degrees. "Extreme weather is caused by increased gradients." Define "gradient" in this context, I'm not sure I follow. Do you simply mean a higher difference between minima and maxima? My argument is that increasing global temps will disrupt long-phase natural fluctuations, and thus likely cause more extreme weather events. "To the extent that CO2 forcing is significant, as modeled it should REDUCE gradients and thus REDUCE storminess." Please provide some sort of science for these affirmations, and that "gradients" are a bigger factor in determining storminess than global temperature increases and the disruption to natural cycles this causes. You have yet to make that case. "I don't think it's that significant." Of course not. Your severe bias agaisnt AGW theory won't allow you to believe otherwise. "There have been weather disasters through out human history in 'warm periods' and 'cool periods'." True, but completely irrelevant.
  18. Hockey stick is broken
    gallopingcamel has kindly moved the discussion of Loehle and Ljungqvist over to the new thread, but I just want to make sure this doesn't remain here un-amended: gallopingcamel wrote This 2000 year reconstruction (Loehle 2008) shows temperature excursions greater than 1 degree Kelvin and Medieval temperatures higher than 2010. It does show a >1K temperature difference between the peak of the MWP and the bottom of the LIA. It does not, however, show Medieval temperatures higher than 2010. In fact, the warmest decades in Loehle's MWP are 0.5K cooler than 2010. Loehle's reconstruction is centered on its own 2000-year mean, and the final datum is from around 1930. In order to compare Loehle's MWP to current temperatures, it is necessary to re-center Loehle's reconstruction to match some other temperature series (e.g., the instrumental record) that actually shows the current temperature. An example of this is included in the update to this post.
  19. New temperature reconstruction vindicates ...
    KR: Yeah, it lacks context. Lots of people conveniently assume that the final point on Loehle's reconstruction is indicative of current temperature. Nope! The quote that Albatross cites a few comments back is rather illuminating. Loehle writes: my own reconstruction is set to a zero baseline for the entire 2000 yrs, so it is only possible to compare to other series that are centered likewise To be technically precise, it would only be possible to directly compare Loehle to other series that are centered on the 2000-year mean of Loehle's own reconstruction. That, of course, is probably the null set. If you want to see whether Loehle's MWP is warmer or cooler than the present, you need to re-center Loehle to match some other series that includes present-day temperatures. This is what we do in the update to the post (above).
  20. New temperature reconstruction vindicates ...
    Nice figure @ 50 Ned. It seems that now matter how you slice and dice the data (i.e., which baseline one uses), Loehle is the outlier. I agree the amplitude of anomalies the Loehle reconstruction are clearly too high for the excellent reason that you provided. If anything, going by that Figure @ 50, Ljungvist agrees best with Mann08, not Loehle08. WUWT should have a post saying that Mann08 has (yet again) been vindicated...not going to happen of course. Anyhow, IMHO, the important observation here is that current warm temperatures in the N. hemisphere are very likely to be unprecedented over the last 1500 years. Exactly how much is difficult to say, but I do not think that one can simply say "we can't be sure today's N. Hemisphere temperatures are warmer than those in the MWP". Zeke has demonstrated that current N. Hemi. temperatures are almost certainly warmer than those observed during the MWP, so has Tamino, apeescape, Ned and Alden......a nice coherent picture. The only incoherence that I can see is in the scrambling and weaseling going on by the "skeptics" and "lukewarmers".
  21. New temperature reconstruction vindicates ...
    OK, I've updated the post (see the "update" above). I particularly like the comparison of LIA and MWP in the various reconstructions, after recentering them all to match the instrumental record as closely as possible during the overlap period: Figure 4. Warmest decades of the Medieval Warm Period, and coolest decades of the Little Ice Age, after re-centering each reconstruction to match the instrumental temperature record during the period of overlap. Moberg is a bit on the cool side overall -- which might just mean it was anomalously warm during the calibration period used for centering. Mann and Ljungqvist agree very closely on the Medieval Warm Period, though Mann's Little Ice Age is not as cold. Loehle manages to be both too warm and too early on the Medieval Warm Period and on the cool side during the Little Ice Age. This difference would not be all that noteworthy, except for the fact that Loehle 2008 is supposed to be a global reconstruction ... and the magnitude of the MWP-LIA difference should almost certainly be smaller for a global reconstruction than for a Northern Hemisphere one. The other obvious point is that when we compare these to the current instrumental temperature record, the Medieval Warm Period seems to be about 0.7 degrees C cooler than the 2000-2010 mean temperature.
  22. Blog review of scientific coherence
    One the one had I like to call the gulliable belief in anything but AGW, the ABCers (anything but CO2). But to put a devils advocate hat on, it is possible to explore alternative ideas without endorsing them. There is a defence of being 'open minded'. It is even possible within science to have to remain open to contradicory ideas while the evidence is built up on which is right. But I think in the cases of the more prominent ABCer blogs this defence fails with the tabloidesque enthusism each idea is greeted with and the lack coherent narrative do weaken such a defence.
  23. Does Climate Change Really Matter?
    Another way of asking, "does climate change really matter?" Just another coincidence in the weather, surely. Graph from this article, which makes today's coverage of the Powell-Mead system in the NY Times look optimistic.
  24. A detailed look at the Little Ice Age
    As I understand it, Milankovitch forcing would strongly indicate that the past 300 years should have been the coolest period of the past 6000.
  25. The Phony War: Lies, Damn Lies and the IPCC
    "you're still missing the point that overall temperatures were lower than today." That is certainly not true for the Arctic or even the Northern Hemisphere, probably not true for the globe. Look at the noise in the whole Holocene ( plus or minus 1 degree C ). We haven't even exceeded that. And as I pointed out, the mean can be meaningless, as the seasonal variation was more extreme in the HCO. Extreme weather is caused by increased gradients. To the extent that CO2 forcing is significant, as modeled it should REDUCE gradients and thus REDUCE storminess. I don't think it's that significant. There have been weather disasters through out human history in 'warm periods' and 'cool periods'. http://www.disastercenter.com/disaster/TOP100K.html
  26. Is Greenland losing ice? (psst, the answer is yes, at an accelerating rate)
    Roger, Do you think that the gulf stream is the exact same thing as the AMOC?
  27. New temperature reconstruction vindicates ...
    Hi Ned, Thanks. That is what I understand reading this (I was trying not to "lead" you). But Loehle seems to be invoking the above quote as evidence that when done his way, his reconstruction is vindicated. Worse still, some are now using that quote above to suggest that people who are trying to realistically compare Loehle's reconstruction with Ljungqvist's are not being honest. But what the heck does one do when Loehle's poor methodology has made it almost impossible to properly compare his reconstruction with those from other paleo groups? IMO, people are nevertheless sincerely trying (despite all the hurdles). Besides why should we take Loehle's word for it? That is how scientists test/validate their colleagues work/hypotheses. Scientists "A" (Loehele) makes an assertion, and others then test said assertion. Well, going by the evidence submitted here and elsewhere Loehle's assertion/hypothesis fails horribly.
  28. Blog review of scientific coherence
    I like where you are going with this but as a non-scientist working to understand it all there is some phrasing that grates a little bit on these American ears. Part of it might be eased by using synonyms in a couple places for "coherence" and "incoherent". I would especially add a short synonymic phrase after this sentence to add emphasis. "Your kids’ future, and the future of their kids, very much depends on logical coherence"... And a suggestion for the last ..instead of "That" use This is the science knowledge that is coherent, backed by peer-reviewed science, and endorsed by all major scientific organizations in the world.
  29. Does Climate Change Really Matter?
    The present Tory UK Foreign Secretary delivers reasons why climate change matters, from a foreign policy perspective: I will first argue that an effective response to climate change underpins our security and prosperity. Second, our response should be to strive for a binding global deal, whatever the setbacks. And third, I will set out why effective deployment of foreign policy assets is crucial to mobilising the political will needed if we are to shape an effective response. To learn more about what a usefully functional conservative grounded in reality sounds like when confronted with facts, click the link.
  30. New temperature reconstruction vindicates ...
    Albatross, my take on that is that there's no direct and uniquely correct way to compare Loehle's reconstruction to anything else (other reconstructions, instrumental temperatures, anything). It's just centered on a value of 0. To compare it to anything else, you have to pick a period of time and assume that both Loehle and whatever-it-is should have the same mean during that period of time, then recenter Loehle's reconstruction to match that mean. Loehle chooses to assume that his reconstruction and Ljungqvist's have the same mean over the entire 2000-year period (I basically did the same in Fig. 2). Alden Griffith's very nice graphic here is based on the assumption that Loehle should have the same mean as the instrumental data during their period of overlap. Both of these are probably defensible choices but it's important to understand the differences. If you're most interested in comparison to the instrumental record, it's probably best to recenter Loehle's reconstruction to match that. Unfortunately, the period of overlap is only 80 years, since Loehle ends so early (1930s).
  31. The Phony War: Lies, Damn Lies and the IPCC
    @CW: you're still missing the point that overall temperatures were lower than today. Sure, humans and polar bears survived the HCO. That's besides the point - what we're seeing today is different than the HCO, it's happening faster, and it's already reached higher global temperatures. As for climate being more extreme, I'm not sure you can be that categorical. I believe a high rate of decadal increase throughout the world (i.e. the current situation) is going to cause more extreme weather events than the relatively stable system in place during the long (even if seasonal minima/maxima were higher in the NH).
  32. The Phony War: Lies, Damn Lies and the IPCC
    scaddenp and archiesteel, The climate was more extreme because the annual variation was greater. (hotter summers, colder winters as discussed) This meant a more extreme seasonal transition. This also meant a greater pole to equator gradient. It is the meridional gradient which is the basis of the thermal wind ( jet stream ). The HCO is NOT an analog of what CO2 is theorized to do. CO2 is theorized to warm some in summer, slightly more in winter. CO2 then is modeled to slightly DECREASE thermal gradient and transitions. However, the HCO IS an important comparison. Greenland, the polar bears, and humans all survived the HCO, and human civilization, as exemplified by the Mesopotamian era, flourished during the HCO. archiesteel, I stand corrected with respect to Absolute Zero. Better stated, the point should read were winters a hundred degrees cooler and summers a hundred degrees warmer, the mean would be zero, which would appear benign, but not at all reflect the extremes.
    Moderator Response: In the interest of readability, please tame whatever device you're using for text input so as to better exploit the white space available for comments. Thank you!
  33. New temperature reconstruction vindicates ...
    Ned, apeescape, Zeke and Alden, First, thanks for your valuable contributions here. There is some squirming going on at AirVent, where Loehle has said this: "but I eventually have remembered that my own reconstruction is set to a zero baseline for the entire 2000 yrs, so it is only possible to compare to other series that are centered likewise." How might doing this affect the comparisons?
  34. Tarcisio José D at 01:14 AM on 30 September 2010
    Blog review of scientific coherence
    Sr Moderador. O argumento de que o vapor de água é o mais importante dos gases de efeito estufa é furado. Quem disse isto pela primeira vez foi John Tyndall nos idos de 1858. Mas com o desenvolvimento da termodinamica da atmosfera, a partir de 1884 quando H. Hertz criou o diagrama denominado "EMAGRAM" pôs em evidencia o mecanismo de convecção vertical que é responçavel por elevar as parcelas de ar aquecido para a alta atmosfera, onde o efeito estufa age ao contrario aumentando a perda de energia para o espaço. Os ceticos não enchergaram isto ??? O vapor de água esquenta como todo o motor que produz trabalho. Mas o trabalho por ele executado deixa um saldo muito positivo para o clima. Mr. Moderator. The argument that water vapor is the most important greenhouse gases are stuck. Who said this first was John Tyndall back in 1858. But with the development of thermodynamics of the atmosphere, since 1884 when H. Hertz has created a diagram called "EMAGRAM" put in evidence the mechanism is vertical convection responçavel for raising portions of heated air into the upper atmosphere, where the greenhouse effect acts contrary to the increasing energy loss to space. Skeptics do not spotting it?? The steam heats the water as any engine that produces work. But the work he does leaves a positive impression for the climate.(google transl)
    Moderator Response: What I meant in my previous comment to you is that you should: 1) Read the post on water vapor. 2) Put your comments about water vapor on that page, not this one.
  35. Blog review of scientific coherence
    Argus, whenever someone refers to Galileo and mainstream dismissal in regards to their theories, I am reminded of a very relevant quote: "But the fact that some geniuses were laughed at does not imply that all who are laughed at are geniuses. They laughed at Columbus, they laughed at Fulton, they laughed at the Wright Brothers. But they also laughed at Bozo the Clown." - Carl Sagan Heliocentric ideas didn't take root until there were (a) reliable measurements contradicting prior theories and (b) newer theories that made some sense, supplying predictive power. AGW skeptics have not satisfied either requirement.
  36. A detailed look at the Little Ice Age
    @Arkadiusz: what is your point? Simply putting quotes without an argument is pretty meaningless, especially since those quotes do not concern the past 50 years, but the period before 1860.
  37. Blog review of scientific coherence
    @Argus: "For a long period in human history, mainstream science agreed that the earth is in the centre of the universe, and that the sun and the planets all revolved around us." I don't think you can talk about "mainstream science" when the scientific method wasn't articulated. You seem to think that, because an idea garners a consensus amongst the learned, then it must be wrong - at least that's what you're suggesting with your cliche of a parable. A more faithful retelling of this story would note it was actual scientists (i.e. who used the scientific method, even though they might not know about it) who figured out the truth, while learned non-scientists thought otherwise. Today, the same kind of people following the scientific method have figured out the current warming is due to anthropogenic CO2, while the same kind of sycophants (this time towards oil companies rather than the clergy and the royalty of Europe) are denying this reality.
  38. New temperature reconstruction vindicates ...
    Ken Lambert writes: Oh, and all the temp charts in this thread seem to stop at year 2000 The data in Ljungqvist 2010 run through the 1990s (they are decadal means). The instrumental data shown in Figure 1 and Figure 2 run through 2010, though it's not particularly relevant at this scale. And; can anybody out there tell me what is the 'equilibrium TSI' and 'equilibrium surface and cloud refection' of the pre-industrial Earth? Without those numbers - an accurate calculation of Solar forcing cannot be made and the relative proportions of CO2GHG and Solar forcing determined over time. Climate forcings can be defined relative to any base period. I don't know why you have this obsession with trying to pin down "equilibrium" conditions, but you shouldn't assume that others here will share that obsession.
  39. Tarcisio José D at 00:04 AM on 30 September 2010
    Blog review of scientific coherence
    Por que a ciencia está equivocada ? Porque não existe equipamento para medir a evaporação real de agua do solo, apenas a evaporação potencial, Como os "modeladores do clima" dependem do indice de umidade do ar, eles estão sendo enganados com os dados de precipitação menos evaporação potencial e em consequencia não põe em evidencia o feedback negativo proporcionado pelo vapor de água , a verdadeira locomotiva do clima. E os ceticos não percebem este bug. Why science is wrong? Because there is no equipment to measure actual evaporation of water from the soil, only the potential evaporation, as the "climate modellers" depend on the moisture index of air, they are being deceived with the data of precipitation less evaporation potential and in consequence not puts in evidence the negative feedback provided by water vapor, the real engine of climate. And the skeptics do not realize this bug.(google tranl.) www.atmos.washington.edu/~stoeling/WH-Ch03.pdf (thermodinamics)
    Moderator Response: See the post Water vapor is the most powerful greenhouse gas.
  40. Arkadiusz Semczyszak at 23:56 PM on 29 September 2010
    A detailed look at the Little Ice Age
    “However, it [the Sun activity] cannot explain the accelerated warming over the past 50 years.” “The variability of the climate during the last millennium is partly forced by changes in total solar irradiance (TSI).: “ Nevertheless, the amplitude of these TSI changes is very small ...” “... the low frequency variability of this mean hemispheric temperature is found to be correlated at 0.74 with the solar forcing for the period 1001–1860.” “... and find a significant relationship between the low frequency TSI forcing and the NAO with a time lag of more than 40 years for the response of the NAO.”
  41. A detailed look at galactic cosmic rays
    #21: Solar cosmic rays are produced by solar wind ions (protons mainly) striking gas nuclei in the upper atmosphere. The flux to the upper atmosphere is thus a product of solar activity (CMEs and flares), observed for several years now by NASA's ACE satellite. The flux at the surface, measured for many years by an international network of neutron monitors and more recently by a network of 'muon counters', varies on a scale of hours, days, months for different types of solar events. These are typically low energy particles, moving at relativistic speeds. The earth's magnetic field (as distinct from the solar or interplanetary magnetic field) is a strong modulator of solar cosmic ray flux. That's why auroral displays (the interaction of charged particles in the earth's magnetic field) are mainly visible in the high latitudes. GCR flux, even in times of the lowest solar magnetic field intensity, is much smaller than solar cosmic ray flux. The key point about GCRs is that they are much higher energy than solar cosmic ray particles.
  42. New temperature reconstruction vindicates ...
    Ned #42 I used to get all excited about these temperature reconstructions too, until I started to understand the forcing imbalance components and the significance of the total energy gain or loss of the earth system over time in explaining warming or cooling of a massive body of land, ice, atmosphere and ocean. Oh, and all the temp charts in this thread seem to stop at year 2000 - missing the last 10 years of flattening at a time when claimed AGW forcing is 'the highest decade in history'. And; can anybody out there tell me what is the 'equilibrium TSI' and 'equilibrium surface and cloud refection' of the pre-industrial Earth? Without those numbers - an accurate calculation of Solar forcing cannot be made and the relative proportions of CO2GHG and Solar forcing determined over time.
    Moderator Response: Depending on exactly what feature of solar behavior you believe may exist alongside GHG forcing, there are treatments of "It's the sun" here, here, here, here, here and here. Note that not all of these are mutually compatible issues.
  43. Is Greenland losing ice? (psst, the answer is yes, at an accelerating rate)
    Ned@28: "Roger, I don't think you have this quite right." Stand corrected.
  44. Blog review of scientific coherence
    Argus, "skeptics" are fond of comparing themselves to Copernicus, Newton, Galileo, and Einstein. But that doesn't mean the analogy is apt. IMHO, your analogy works better the other way around. For a long time, popular belief held that [the Earth was the center of the Universe / humans cannot modify the climate]. Gradually, however, scientists began to realize that this was not the case. Among scientists, this previous worldview was replaced by the idea that [the Earth revolves around the Sun / anthropogenic greenhouse gas emissions can warm the climate]. For a number of reasons -- political, ideological, and personal -- this conclusion was resisted by powerful institutions outside of science, and scientists who supported the new worldview [Galileo / climate scientists today] were harassed by those institutions. Eventually, however, the evidence became overwhelming and those who had previously resisted the new paradigm were no longer able to resist the ever increasing mountain of evidence in support of the new scientific consensus....
  45. New temperature reconstruction vindicates ...
    Alexandre: Loehle´s reconstruction deserves less attention than the unpretentious reconstruction Peter Hogarth did here some time ago. Seconded. That was an extremely nice analysis; the comparison between proxies and instruments 1850- was especially intriguing.
  46. Is Greenland losing ice? (psst, the answer is yes, at an accelerating rate)
    Roger@27: Sorry, I meant to say, "temporary reprieve from global warming," not "temporary respite from global warming." Well, either may be applicable...
  47. Blog review of scientific coherence
    For a long period in human history, mainstream science agreed that the earth is in the centre of the universe, and that the sun and the planets all revolved around us. It seemed to fit common sense and current scientific knowledge. Just take a look at the sky! Refined subtheories were invented to explain certain mysterious behaviour of the planets (as epicycles). Everything was coherent and nice. Of course there were also some "skeptics" or "denialists" in those times, who refused to believe the obvious truth: that earth is the centre. Unfortunately they did not all agree with each other, which is very suspicious to start with. Some of them advocated a rival theory that we now call heliocentric. During 2000 years, from Yajnavalkya and Heraclides, via Aryabhata and Martianus Capella, to Copernicus and Galilei, there were many thinkers who doubted the official theory, and made various attempts to put the sun in the centre. They were often, consequently, ridiculed (or worse). The sum total of so-called "skeptic" arguments against the geocentric model was an "incoherent muddle of contradictions". In spite of the incoherency, science finally moved forward to heliocentrism and further on to our present beliefs.
    Response: Don't count your chickens... www.galileowaswrong.com
  48. Is Greenland losing ice? (psst, the answer is yes, at an accelerating rate)
    Roger, I don't think you have this quite right. The driving factor in North Atlantic deepwater formation is salinity, and the presence of a lens of fresh water on the surface will reduce the vertical flux. From Ganopolski and Rahmstorf 2001: For a large freshwater input (such as a large release of icebergs), the model's deep water formation is temporarily switched off ... From Hu et al. 2009: Since Greenland is close to ocean deep convection sites associated with the oceanic meridional overturning circulation (MOC), the discharge of the melting ice sheet water could potentially stabilize the upper ocean at these sites and lead to significantly weakened deep convection there. Presently, some modelling studies indicate a dramatic weakening of the MOC in a future warmer climate after the melting is taken into account ... From Jungclaus et al. 2006: Climate projections for the 21st century indicate a gradual decrease of the Atlantic Meridional Overturning Circulation (AMOC). The weakening could be accelerated substantially by meltwater input from the Greenland Ice Sheet (GIS). Here we repeat recent experiments conducted for the Intergovernmental Panel of Climate Change, providing an idealized additional source of freshwater along Greenland's coast. For conservative and high melting estimates, the AMOC reduction is 35% and 42%, respectively, compared to a weakening of 30% for the original A1B scenario. Even for the high meltwater estimate the AMOC recovers in the 22nd century. and so forth. The conventional description of this is clearly that a reduction in surface salinity caused by inputs of meltwater from decaying ice caps will reduce the vertical flux in deepwater formation zones and lead to a slowdown in the MOC. I have never read an explanation that matches your description of this process, so if you've got a reference to a study showing this, I'd be very interested in reading it. That's not to say that meltwater from the Greenland ice sheet would cause some kind of "Day After Tomorrow" catastrophe. But the general effect is to reduce rather than increase the meridional overturning circulation; RSVP did indeed have this backwards.
  49. New temperature reconstruction vindicates ...
    IMHO, Loehle´s reconstruction deserves less attention than the unpretentious reconstruction Peter Hogarth did here some time ago. Loehle did his best to exaggerate the MWP, LIA and -for added effect- cut off the last 70 years or so, effectively "hiding the rise". To be a denier is a good way of getting attention.
  50. Blog review of scientific coherence
    Stephan Lewandowsky at 21:13 PM on 29 September, 2010 Mythago, would prefer for this to remain limited in circulation till reposting of final version next week (Wednesday, together with podcast on RTR at the same time). SL Got the message and will wait until then to share the good news as it were (with your permission of course)?
    Moderator Response: Sure thing, once posted it's public and feel free to circulate. SL

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