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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

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Comments 102251 to 102300:

  1. Renewable Baseload Energy
    I need to research quokka's comments of nuclear load following. I think he's conflating two different things. The fundamental principle with nuclear is that it's either on or off (as I understand it). You can't just stop the reaction and have very limited capacity to alter the rate of the reaction in the chamber. That is not to say the plant itself can not adjust the rate they are generating electricity. But you are, none-the-less, burning nuclear fuel even if the turbines are off.
  2. The human fingerprint in the seasons
    RSVP @85, the most important flaw with your caclulation is that forcing does not rise linearly with increased concentration, but rather with the log of increased concentration. By best current scientific estimate, the change in forcing in watts per square meter is expected to be 5.35 x the natural log of the current concentration divided by the initial concentration. Doing the maths, we then expect a no feedback temperature rise of 0.5 degrees c with an increase of CO2 from 280 to 380 ppm, and a rise of 1.25 degrees c after fast feebacks, once equilibrium is achieved. Given that it takes up to 30 years to achieve the equilibrium responce, the 0.9 degree rise in temperature since 1850 shown in the graph directly above your post seems well within expectations.
  3. 2nd law of thermodynamics contradicts greenhouse theory
    Thanks for digging up damorbel's rap sheet. I'm going to ignore him or her from now on.
  4. Newcomers, Start Here
    Thank you John Cook for the site and the starter series. My background is not science - it is political science. Became interested in BOINC a few years ago and now I contribute millions of CPU cycles to Climate Prediction. The BBC Climate Prediction effort is the largest grid computing project of its kind anywhere. Their purpose is to make climate prediction models more accurate and useful. Are these efforts helpful in actually advancing your science? I have blogged about this a lot. Gypsy Chief Blog Thanks.
  5. A Cloudy Outlook for Low Climate Sensitivity
    Dana, Great post and thanks for covering this important topic. I was hoping SS was going to cover the Lauer et al. (2010) paper and you did not disappoint. Could the "skeptics" please tell us when this supposed (and mysterious) significant negative cloud feedback is going to kick in? It has not kicked in, and the only reliable, coherent data and studies argue against a significant negative feedback. The long term warming continues in the 0.15 to 0.20 C per decade range, as per RSS data and as per Hansen et al's latest paper.
  6. A basic overview of Antarctic ice
    Philippe said: "What is the point of such manipulations?" You misunderstand. Those are not manipulations those are roughly the actual numbers. As Albatross did in post #74 he found significant negative ice in the Arctic in 3 of 5 solstice months he tested. And he found significant positive ice in the Antarctic in 1 of 5. So all the paragraph is an estimate of how the combined polar ice, since they are of opposite signs, ends up with ratios similar to the antarctic instead of the arctic (still negative but a negative ratio similar to the antarctic ratio). The percentages when you multiply them show that to be roughly the case. Thus it is likely that mathematically the change in global sea ice is not statistically significant even though it is in some cases regionally.
  7. 2nd law of thermodynamics contradicts greenhouse theory
    Tom, I came to that conclusion about damorbel many posts ago. If you believe that your own version of physics is right and all textbooks are wrong and you determine not to learn otherwise, then noone can teach you. We are wasting time. I sure hope the person that taught him physics isnt still in a job.
  8. The human fingerprint in the seasons
    84 (muoncounter), I'm not sure you can do that. It's bootstrapping. More specifically, you are trying to prove that there is a unique GHG signature to warming by adopting the premise that warming prior to 1979 was a result of increased TSI (an unsupported premise, but lets skip that), and warming after 1979 was a result of CO2 (GHG). Having thus proved that GHG warming has a different signature (using the premise that warming after 1979 was a result of CO2), you then want to prove that warming after 1979 was a result of CO2, because it has a different signature. That said, I would be interested to hear a climate scientist's take on the fact that all warming of any sort should include substantial GHG feedbacks, and yet the signature warmer winters for GHG are only present after CO2 warming kicked in. This would seem to me to argue against a strong H2O/CO2 feedback. It implies that there was no GHG component at all to warming prior to 1979, and you can't have it both ways, you can't have a climate sensitivity with positive feedbacks that only kick in for CO2 but not for other forcings. Given this, it therefore implies a lower climate sensitivity across the board (which hardly seems to be the case, given the preponderance of other evidence to the contrary).
  9. Eric (skeptic) at 09:45 AM on 6 December 2010
    A Cloudy Outlook for Low Climate Sensitivity
    archiesteel, TSI is not a very useful measurement. UV and other components are more useful since UV modulates blocking and blocking modulates sensitivity. By damping I meant that about 1/2 of man's contribution of CO2 to the atmosphere is absorbed by nature. Since I can't predict solar and GCR, I can't say whether it will mitigate or worsen AGW. Dana, thanks for addressing my assertions, hopefully I can clarify and maybe some are still wrong after I do. I definitely consider CO2 as a forcing, but it has also been considered a feedback in various threads including the paleo sensitivity threads where it is (IMO incorrectly) considered to be the primary feedback, so that's why I mentioned that. The recent warming (2C per century peak rate) has had many short term fluctuations, hardly representative of the long term sensitivity. I agree with your third point, but it consists of a modest warming effect from GHG before considering sensitivity. Methane varies greatly in the short term and no long term sensitivity conclusions can be made. I agree with your fifth point because water vapor will increase on average with evenness being the big unknown. My argument is a little different Lindzen and Spencer as I see a greater effect from external factors, not in their models and not in their critics models, on clouds. You previously dismissed GCR in the thread I linked to only by hypothesizing it as the only factor, comparing the linear trend with linear temperature trend and seeing no correlation. But the only possible conclusion is that GCR did not exceed other factors in the last 30 years, not that GCR has no influence. It clearly has a substantial influence on clouds, but those cloud changes do not directly control temperature but mostly weather. In the past 30 years, other factors, both terrestrial and not, have had a larger influence on weather. The reaction of weather to these factors is what sensitivity is.
  10. 2nd law of thermodynamics contradicts greenhouse theory
    Tom Dayton wrote : "Do you really believe you are the lone genius on Earth who truly understands the second law of thermodynamics?" I think the answer to this, in damorbel's mind, is 'yes'. I'm not being insulting but I think everyone should look at this Wikipedia page, which seems to be the same damorbel going through the same arguments, with others attempting what you are all trying to explain here. What is the point and why should anyone be allowed to do this here ?
  11. 2nd law of thermodynamics contradicts greenhouse theory
    damorbel, you completely missed the point archiesteel made. He was countering your claim that reflection of radiation incoming to the Earth must be matched by reflection of radiation outgoing from the Earth. A large part of the reflection of the incoming radiation is by things on the ground. Since the radiation outgoing from the Earth is headed away from things on the ground, the things on the ground cannot reflect it. So the reflection of outgoing cannot automatically be the same as the reflection of incoming, since the reflectors in the two cases are different.
  12. 2nd law of thermodynamics contradicts greenhouse theory
    @damorbel: it is averaged to obtain the entire planet's albedo, sure, but that doesn't mean this accurately describes the actual reflection at any given location on the globe. Anyway, that's besides the point. You seem not to understand the fact that we are talking about two different types of radiation, i.e. short-wave (visible light, ultraviolet, etc.) and long-wave radiation (infrared). CO2 and greenhouse gases absorb and re-emit the latter, not the former. That is the so-called greenhouse effect. A higher albedo means less of the energy is converted from short-wave to long-wave by the surface, i.e. the latter's temperature doesn't increase as much; therefore a higher albedo value usually means colder temperature.
  13. 2nd law of thermodynamics contradicts greenhouse theory
    damorbel, multilayer insulation works even when its surfaces are not coated with reflective material. Read that article again--carefully this time. Oh, wait, you've now decided the article you yourself first pointed to as support is wrong, now that we have forced you to actually read it. In fact, you believe everyone on the planet but you is wrong--everything that everyone has told you, and everything that we've told you to read, and now something that you told the rest of us to read. Do you really believe you are the lone genius on Earth who truly understands the second law of thermodynamics?
  14. 2nd law of thermodynamics contradicts greenhouse theory
    Re #302 archiesteel you wrote:- "You seem to believe that albedo is solely determined by atmospheric (i.e. "above-ground") conditions, but a lot of the actual albedo is determined by the actual reflectiveness of the Earth's surface (water, rock, vegetation, deserts, polar caps, etc.)." The albedo is the radiation reflected by an object in space, it is the average over the surface.
  15. Positive feedback means runaway warming
    Here's a quote from a 2008 paper, posted on the National Energy Technology Lab website, that uses the Tough +/Hydrate computer code for simulating methane hydrate dissociation. MODELING OF OCEANIC GAS HYDRATE INSTABILITY AND METHANE RELEASE IN RESPONSE TO CLIMATE CHANGE
    Two of the most recent studies, each accounting for the coupled contribution of organic matter decomposition and mass transport, have produced drastically different results. Klauda and Sandler [8] provide an upper estimate of 74,400 Gt of methane carbon in hydrate form (27,300 Gt along continental margins, while Buffett and Archer [9] used both compaction and advection in a 1-D methanogenesis/hydrate formation model to reach an estimate of 3,000 Gt of methane in hydrate and 2,000 Gt of gaseous methane existing in a stable state under current climate conditions.
    This paper seems to show increased levels of hydrate release for shallow hydrate deposits with less than a one degree C temperature increase. There are chemical reactions that oxidize the methane or transform it into bicarbonate that I was not aware of until recently. Still, the bigger the reservoir, the smaller the percentage that has to dissociate to cause the climate serious or catastrophic harm.
  16. A Cloudy Outlook for Low Climate Sensitivity
    Eric #50, you've made a number of incorrect statements. Firstly, that CO2 has been a slow feedback at times in the past does not mean it must always be a slow feedback - that's a basic logical fallacy. Besides which, it's not currently a feedback, it's a forcing. Secondly, the planet is already warming at nearly 2°C per century, so it's already not acting slowly. Third, while future changes in solar and other natural factors are hard to predict, that's not really relevant. Maybe the Sun will be a positive forcing, maybe a negative one, maybe a neutral one. What we do know is that greenhouse gases are a large positive forcing which will continue to have a warming effect. Fourth, permafrost is already melting and releasing methane, thus you're once again contradicting empirical observations by claiming this feedback will take centuries. Fifth, there's not much question that water vapor will be a positive feedback, the only real question is how strong that feedback will be. Sixth, it's the argument of Lindzen and Spencer etc. that a negative cloud feedback will prevent significant warming. I didn't make it up - I was addressing their argument. And seventh, the galactic cosmic ray influence on the global climate has been demonstrated to be minimal.
  17. 2nd law of thermodynamics contradicts greenhouse theory
    Re #303 Tom Dayton you wrote:- "apparently you really did not read the article you linked to. Go read it. Really, read it. Notice the explanation of the non-reflective mechanism by which it operates." You are right. But the article, which says :- "the principle behind MLI is radiation balance. To see why it works, start with a concrete example - imagine a square meter of a surface in outer space, at 300 K, with an emissivity of 1, facing away from the sun or other heat sources. From the Stefan-Boltzmann law, this surface will radiate 460 watts. Now imagine we place a thin (but opaque) layer 1 cm away from the plate, thermally insulated from it, and also with an emissivity of 1. This new layer will cool until it is radiating 230 watts from each side, at which point everything is in balance." is wrong; it says (5lines down) "and also with an emissivity of 1. This new layer will cool until it is radiating 230 watts." The whole principle of reflective insulation is using material with low emissivity. Initially satellites used gold plating as a barier against heat tranfer. Gold has an emissivity <0.05, depending on the finish. Also the well known silver teapot (emissivity = 0.02 - 0.03) has only one emitting surface, it keeps the tea hot better than any other material. Further, the vacuum flask the vacuum flask has only two layers and achieves far greater insulation than the explanation given in the 'Multi Layer article. When you write :- "Notice the explanation of the non-reflective mechanism by which it operates." I do not know what you mean. These materials work best in a vacuum which is the case for Sun/Earth heat transfer. In #304 you write:- "reflection (scattering) does depend on frequency. That's why the sky is blue." This wavelength dependence of scattering has no effect on total transfer of heat when at the equilibrium temperature, if it did there could be no equilibrium.
  18. The human fingerprint in the seasons
    actually thoughfull (way back @74 on molecules being interviewed) No this was not what I was suggesting :-) The point was that if there was a solar forcing causing increased WV in the atmosphere, then wouldn't the concentration of WV in the atmosphere (and hence the feedback) follow the forcing as it moved from hemisphere to hemisphere because of the differing temperatures of the atmosphere over the summer and winter locations. In contrast a CO2 forcing would not have a seasonal fluctuation and so the seasonal feedback (WV) variation would be less. If this were true then HR's objection to the original article is invalid: even with WV feedback, a Solar forcing would still result in summers warming faster than winters. Any clearer ?
  19. A Cloudy Outlook for Low Climate Sensitivity
    @Eric (skeptic): you are exaggerating the impact of TSI and galactic cosmic rays. Also, what do you mean by "obviously nature is damping man's additional CO2"? The problem with your theory is that it is not confirmed by oservation. There is no indication that external factors such as TSI or GCR could overcome AGW. Until you have actual evidence supporting your theory, we'll have to continue assuming it is very unlikely.
  20. A Cloudy Outlook for Low Climate Sensitivity
    @Camburn: "The temperature trend for the past 15 years has been flat." No, it isn't. Please acknowledge you are wrong about this. Thanks.
  21. The human fingerprint in the seasons
    @RSVP: why don't you tell me right away where you're trying to go with this, so we save some tiem? The resl question is, why not take the middle value, i.e. 17.5%? That gives us 1.365C. So, what about it? You seem to be missing the point I already demonstrated how your "equation" was wrong. The fact you avoided responding to my counter-arguments is all we really need to know. Thanks for playing.
  22. Eric (skeptic) at 08:28 AM on 6 December 2010
    A Cloudy Outlook for Low Climate Sensitivity
    #25 archiesteel "....with a possible increase over [CO2 warming] due to increased solar activity." and #26 muoncounter "We can all play 'what if' ... if you like." Thank you for your responses. The sensitivity to CO2 warming is by definition a 'what if' game because sensitivity is modulated by external factors (solar and celestial) which are not predictable, they can go either way. A paleo-based calculation of sensitivity has to consider variations in external factors, solar or not (e.g. GCR) which are not adequately represented in the paleo record. When GCRs increase or decrease due to some celestial cause (modulated by the sun), both the paleo temperatures decrease or increase in response and CO2 follows. We see that happen in centuries or longer (not to mention that's all the resolution that we have in ice core and other proxies). So CO2 feedback is a minor and slow feedback factor; paleo or present day (obviously nature is damping man's additional CO2, not amplifying it). Thus the CAGW hypothesis depends on water vapor amplification of CO2 warming. Talking about methane is likewise not convincing since it will take centuries for enough permafrost to melt to get methane feedback. Water vapor is partly covered in the cloud discussion above and partly not. The non-cloud portion of the water vapor feedback depends on the distribution of water vapor (the evenness) which in turn is somewhat dependent on clouds, but also winds, precipitation, soil moisture, etc. The claim that the major uncertainty in sensitivity can be adequately covered by examining a handful of modeled and measured cloud types and a few parameters (optical depth and albedo) is not correct. The amplification of CO2 warming by water vapor is determined by planet-worth of weather such as the oft-trumpeted claim of more numerous storms (a negative feedback). Numerous water vapor modulations must be considered and, more importantly, the external factors like GCR can scramble the entire equation. Thus predictions are by definition a what-if game but those external factors also modulate sensitivity and are not considered at all in the models referenced above.
  23. A Cloudy Outlook for Low Climate Sensitivity
    "Yet, they ignore the warmth of the early and mid 20th century." Camburn, this is patently false. Why dont you read the IPCC WG1 to see how false. "AGW" is not so much a theory as an outcome of the theory of climate - which basically says that climate will respond to whatever is the net value of the forcings present. Funnily enough the forcings (solar, aerosol, GHG) have all varied the last century and climate change has followed our best estimates for what those net forcing were - not just in terms of temperature but also in terms of the fingerprint (summer/winter temps etc) expected. Ignored my foot. Its covered in depth in the published science.
  24. 2nd law of thermodynamics contradicts greenhouse theory
    damorbel, reflection (scattering) does depend on frequency. That's why the sky is blue.
  25. A Cloudy Outlook for Low Climate Sensitivity
    Camburn, again this isn't the place to argue about temperature trends, but here is the exact same data you plotted, but with a linear trend added. As you can see, it is not flat - not even close, aside from the fact that HadCRUT shows less warming than data sets which account for the Arctic. But back to the subject at hand, while it's true that these are regional studies, they are of a very critical region. As I quoted from the Stowasser 2006 study, "In terms of the sensitivity of the global-mean surface temperature, almost all the differences among the models could be attributed to differences in the shortwave cloud feedbacks in the tropical and subtropical regions." And climate sensitivity studies do not ignore previous warm (or cold) periods. Quite the opposite.
  26. The human fingerprint in the seasons
    archisteel #87 "I'd also like to point out that *you* picked the higher value for the relative participation of CO2 to the greenhouse effect... " So taking the low value instead, "we" get 0.09 x 0.25 = 0.0225 x 30 = .68 degree"s" C, which apparently accounts for all the world's glaciers to be receding and observed ice melt acceleration in Greenland. Do you believe this?
  27. A Cloudy Outlook for Low Climate Sensitivity
    I am not a good poster but hopefully this will work: http://woodfortrees.org/plot/hadcrut3vgl/from:1995/to:2010 The temperature trend for the past 15 years has been flat. That should be a start for "small extent". And this temp chart brings us back to co2 and climate sensativity as a whole. People will want to point to warming since 1970 as evidence of AGW. Yet, they ignore the warmth of the early and mid 20th century. http://woodfortrees.org/plot/hadcrut3vgl/from:1850/to:2010 It took until the early 1980's to recover to levels exibited in the 1870's and 1940's. And this is getting so far off topic. Look at the temperature graphs. I used hadcrut3 gloabal. Hope that is acceptable.
  28. 2nd law of thermodynamics contradicts greenhouse theory
    No, damorbel, multilayer thermal blankets do not operate solely by reflection. Apparently you really did not read the article you linked to. Go read it. Really, read it. Notice the explanation of the non-reflective mechanism by which it operates.
  29. A Cloudy Outlook for Low Climate Sensitivity
    Camburn wrote : "Show me this evidence that is verifiable and not modeled, but observed." So, I have pointed you towards some observational studies, and the lead article has more, but then you move onto : "Again, I will state that the level of certainty in the models concerning clouds is not there." But what about the observations, then ? You also quickly moved onto : I am thinking on a global scale in regard to studies after first stating : A small area of the world is a start, but we all know regional variances do NOT make climate. What is it, exactly, that you are trying to argue for ? And why do you imagine that "regional variances" have no effect on regional climates ? Camburn wrote : "After all, GAGW is still in the hypothosis stage and has not advanced to theory stage." G(or C)AGW, whatever either of them mean (each so-called skeptic has their own personal views of what they believe AGW means and what they think the 'C' bit means - means nothing to the rest of us) is a strawman. AGW is a theory, as strong as any other theories, e.g. Evolution. Look up the difference between Theory and Hypothesis. Camburn wrote : "Does co2 play a factor in climate. Yes, to a small extent." Can you reveal your sources for that "small extent" ?
  30. The human fingerprint in the seasons
    @AT: I was referring to the study that showed increased heat where it wasn't expected, i.e. the deep oceans. The story about deep lake showing warming is another example of this. I don't have links handy, but I'm sure a quick search on this site would bring the study up.
  31. Renewable Baseload Energy
    Michael sweet, I am aware that reference is pro-nuclear but it had the advantage of other comparisons in that it had numbers for other generation that match what I know to be correct. Do you have a source for nuclear costs that you think has better estimates from an independent authority? Getting subsidy-free, unbiased numbers is really difficult - far more difficult than it should be. As David MacKay has pointed out, you cant have a debate without it being informed by accurate numbers.
  32. A Cloudy Outlook for Low Climate Sensitivity
    @Camburn: temperatures are already at similar levels to that of the Holocene (if you look at the entire globe). "I have read papers that go both plus and minus as far as sensativity. With that in mind, I have to think that the sensativity issue is still wide open." The fact that there exists two points of view on the same issue does not mean the two points of view are equally valid. The fact is that a preponderance of papers argue for high sensitivity, and are supported by evidence, does count. It's not enough to read papers, you also have to understand them and be able to evaluate their merit. The fact you feel the issue is still "wide open" is a clear sign this isn't what you're doing.
  33. 2nd law of thermodynamics contradicts greenhouse theory
    @damorbel: "The Earth reflects back 30% of the radiation coming from the Sun, isn't 30% of the radiation coming from the Earth going to get reflected back in the same way?" You seem to believe that albedo is solely determined by atmospheric (i.e. "above-ground") conditions, but a lot of the actual albedo is determined by the actual reflectiveness of the Earth's surface (water, rock, vegetation, deserts, polar caps, etc.). In that sense, a significant portion of the energy reflected to space cannot be reflected back to the ground, because the ground itself is what's reflecting it.
  34. Ocean acidification isn't serious
    I responds to this over on #148 of "we're heading into an ice age".
  35. We're heading into an ice age
    cjshaker - Note that 100,000 year cycle isnt the main player in glacial cycle - are you seriously suggesting that you dont think the Milankovich cycles are the primary forcing? Modelling of ice age on the whole is fairly crude - running models that are used for predicting the next 100 years over a million years isnt feasible with current computer power, so yes, its still active research. You have competing explanations for the relative importance of various feedbacks in reproducing the cycle and so far no clear winner. For discussion of research and pointers to the papers on the models, then you cant go past Chp 6 of IPCC WG1.
  36. actually thoughtful at 06:45 AM on 6 December 2010
    The human fingerprint in the seasons
    archiesteel - OHC is the last great unknown regarding AGW - do you have recent data or papers which inform your comment "Add to this the fact that oceans are apparently soaking up more heat than we previously thought (even in the deeper layers of the ocean)." I read last week that deep lakes were showing warming (sorry to say I don't have a link).
  37. The human fingerprint in the seasons
    @muoncounter wins the thread, IMHO.
  38. The human fingerprint in the seasons
    I'd also like to point out that *you* picked the higher value for the relative participation of CO2 to the greenhouse effect...
  39. The human fingerprint in the seasons
    @RSVP: there are some issues with your math. First, most of the anthropogenic CO2 rise happened in the last few decades. Second, warming due to CO2 doesn't take place immediately, unlike what your reasoning implies. Combine the two point, and it becomes clear we haven't experienced the full impact of the warming for the *current* CO2 concentration (nevermind from increased CO2 in the future). Add to this the fact that oceans are apparently soaking up more heat than we previously thought (even in the deeper layers of the ocean), and you've got a pretty good explanation why temperatures have only risen by 1C so far. Nice try, though.
  40. 2nd law of thermodynamics contradicts greenhouse theory
    Re #299 Ned you wrote:- "Damorbel, did you ever read the last paragraph of this comment? Did you understand it?" Is this from your paragraph:- "If the albedo of the earth increased, it will receive less short-wavelength radiation (visible, near-infrared). But this doesn't imply an immediate, corresponding reduction in outgoing long-wavelength radiation"? How so? Isn't the outgoing radiation scattered by the same material that scatters the incoming radiation to give the albedo? And further you wrote:- "I'd also note that damorbel has still not explained why he/she approvingly cites an explanation at wikipedia that explicitly relies on the exact same mechanism that he/she thinks violates the 2nd law of thermodynamics." Which is just a multilayer metalised thermal blanket. Thermal blankets don't break any laws of themodynamics because it doesn't matter which way the radiation comes or on its wavelength. They work by reflecting radiation in both directions; a metalised themal blanket doesn't have to be 100% opaque, it could be 30%; reflecting just 30%, same as the Earth. The Earth reflects back 30% of the radiation coming from the Sun, isn't 30% of the radiation coming from the Earth going to get reflected back in the same way? The Earth is not equipped with a one-way mirror that reflects 30% of the Sunlight but transmits its own radiation 100% (making it behave like a black body); no way does that happen in real physics.
  41. A Cloudy Outlook for Low Climate Sensitivity
    As Camburn notes, this really isn't the place to argue whether warmer is better. Nevertheless since the issue has been raised, I will make one comment on the subject. There is quite obviously a point at which warmer is no longer better, otherwise we could live on Venus. I think Daniel Bailey's first graphic in comment #41 illustrates quite nicely that we can no longer use past human civilizations to assess whether "warmer is better" because we're about to move well outside the range of temperatures experienced during those civilizations. "Warmer is better" is a huge oversimplification.
    Moderator Response: Everybody please comment on whether warming is bad on the thread...wait for it...It’s not bad.
  42. The human fingerprint in the seasons
    archiesteel #81 It is my understanding that anthropogenic CO2 comprises 100 ppm of the 380 ppm, which is 26 percent of the 26% you have cited (taking the larger value)... .26 x .26 = 0.068. If greenhouse gases in sum have raised temperatures 30 degrees C, it would appear that the Earth has warmed 30 x .068 = 2.028 C since 1850 or so. Is this the case?
  43. A Cloudy Outlook for Low Climate Sensitivity
    Great post. Very useful, clear and authoritative. Many thanks.
  44. Ocean acidification isn't serious
    Rob I've been reading about dramatic temperature changes in the recent past, documented from temperature proxy data retrieved from the ice cores. http://www.scientificamerican.com/article.cfm?id=ice-core-reveals-how-quickly-climate-can-change "Following this abrupt shift, as much as 20 degrees Fahrenheit (10 degrees Celsius) of warming occurred over the subsequent decades—a change that ultimately resulted in at least 33 feet (10 meters) of sea-level rise as the ice melted on Greenland." http://www.sciencedaily.com/releases/2008/06/080619142112.htm "The ice core showed the Northern Hemisphere briefly emerged from the last ice age some 14,700 years ago with a 22-degree-Fahrenheit spike in just 50 years, then plunged back into icy conditions before abruptly warming again about 11,700 years ago. Startlingly, the Greenland ice core evidence showed that a massive "reorganization" of atmospheric circulation in the Northern Hemisphere coincided with each temperature spurt, with each reorganization taking just one or two years, said the study authors." These seem like pretty massive and rapid climate changes to me. Chris Shaker
    Moderator Response: This discussion has drifted off the topic of this thread. Everybody please start commenting on the appropriate threads.
  45. The human fingerprint in the seasons
    #80: "tangled everything in knots as artfully as the most adept "skeptic."" Ouch. Hardly my intent; most definitely not my meaning. "This makes the statement that "a TSI forcing would not exhibit warmer winters and nights" false." Let's test this idea. Here is a well-known TSI reconstruction: Surely we can agree that this graph shows the period of 1910-1945 or so had a fairly consistent run-up in TSI, what one might call a 'solar forcing'. Now for a temperature anomaly graph, attempting to show summer (green) and winter (red) in the NH, with a sunspot curve (blue) filtered to mimic the shape of the TSI graph. The sunspot curve is normalized to fit on the page and shifted down for clarity. The temp anomalies during this early 20th century TSI forcing have summers (green) warming faster than winters (red). The temp anomalies during the recent warming (which some feel is due to increased GHG concentration) have winters (red) warming faster than summers (green). Hence, a TSI forcing does not exhibit the same signature as a GHG warming.
  46. A Cloudy Outlook for Low Climate Sensitivity
    Nick@40. I feel very lucky. Yooper@41. Ag isn't going to end. This is the end of my off topic additions. We shall save those for threads that talk about the subjects raised that were off topic. Thank you.
  47. actually thoughtful at 06:05 AM on 6 December 2010
    The human fingerprint in the seasons
    Sphaerica @77, Thanks for presenting these points. You said "Any warming, of any sort, will be accompanied by roughly 2C of GHG positive feedback in addition to the initial forcing. That means that any warming will have these same signatures (although to differing degrees)." And then @ 80 "This makes the statement that "a TSI forcing would not exhibit warmer winters and nights" false." These are very interesting points, if true. Elsewhere on this site, based on published papers, the following point is made, which seems to completely contradict your point: "If an increased greenhouse effect was causing warming, we would expect nights to warm faster than days. This is because the greenhouse effect operates day and night. Conversely, if global warming was caused by the sun, we would expect the warming trend to be greatest in daytime temperatures. What we observe is a decrease in cold nights greater than the decrease in cold days, and an increase in warm nights greater than the increase in warm days (Alexander 2006, Fan 2010). This is consistent with greenhouse warming." http://www.skepticalscience.com/its-not-us-intermediate.htm If you can counter that argument, would you post it there, but leave a bread trail here that you did so?
  48. We're heading into an ice age
    Muoncounter: yes, and they talked about tweaking the model to get it to reflect the 100,000 year cycles. I found the whole idea of the ice-sheet bedrock uplift fascinating. I have not yet found newer studies which attempt to model and predict the glacial cycle. Is it still an active area of research? Chris Shaker
  49. Ocean acidification isn't serious
    I remain curious as to why coral are so temperature sensitive Chris, were the Earth (and sea temperatures) not warming so rapidly, it's likely that coral would be able to adapt, by acquiring less temperature sensitive photo-symbionts. Like other changes in the Earth system, it's the speed of change that is the problem.
  50. Ocean acidification isn't serious
    Muoncounter - We don't do photosynthesis. The corals in shallow water reefs are a symbiosis between the coral polyp and photosynthesizing algae. The algae provide nutrients to the polyp via photosynthesis and in exchange get shelter and protection. Typically too warm waters (above the photo-symbiont's tolerance) leads to a shut down in photosynthesis and because they are no longer getting food, the polyps expel the algae, hence the "bleaching" of colours which the algae produce. So although the polyp may not photosynthesize, it is certainly dependent on it for survival.

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