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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 102301 to 102350:

  1. 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.
  2. 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?
  3. A Cloudy Outlook for Low Climate Sensitivity
    Great post. Very useful, clear and authoritative. Many thanks.
  4. 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.
  5. 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.
  6. 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.
  7. 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?
  8. 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
  9. 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.
  10. 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.
  11. Ocean acidification isn't serious
    I remain curious as to why coral are so temperature sensitive, considering that they have evolved during millions of years of the glacial cycle? As of 1950, we were still 4.5C short of the temperature high achieved during the previous warming phase. The glacial cycle causes large climate changes. Why have coral not evolved to be more flexible about temperature? Chris Shaker
  12. Ocean acidification isn't serious
    Muoncounter: you might want to read replies from Rob Painting. Coral is a symbiotic organism, basically an algae inside the animal. The algae provides energy for the coral from photosynthesis. Chris Shaker
  13. A Cloudy Outlook for Low Climate Sensitivity
    Re: Camburn Once upon a time, warmer seems to have been better. Let's look at that graphically, shall we? But with what we know of the radiative forcing of CO2 and its status as the Chief Control Knob of Temperatures, consider this graph carefully: At some point we may have to update the top graph with an arrow with this legend:
    "Agriculture ends"
     Let the good times roll... The Yooper
  14. A Cloudy Outlook for Low Climate Sensitivity
    Camburn #39 Possibly warmer might be better in the long run once the climate has settled down to the new equilibrium but there might be horrendous instabilities in the interim period. Do you feel lucky?
  15. A Cloudy Outlook for Low Climate Sensitivity
    dhogaza@36: Past temp proxies and the advancement of mankind indicate that warmer is better. The Golden Age of the Holocene happened at the optimum. Back to clouds tho.
  16. A Cloudy Outlook for Low Climate Sensitivity
    I don't know enough about the physics of clouds to be certain, so I might sound a bit naive by saying the following. Isn't the Lindzen/Spencer scenario that the small increase in planetary average temperature from increasing CO2 will cause the relative humidity to increase, primarily in the troposphere - extra water vapour will be present and will lead to the formation of larger, or more numerous, clouds, which will reflect back sunlight thus cooling us back down in a negative feedback? Where I might be naive is that, as a hang glider pilot, I know, because I have felt it (we're right out in the air flow) that in the gaps between the clouds there is plenty of water vapour too. If Lindzen et al speculate that the feedback from increasing water vapour is negative because of the increase in planetary albedo due to more clouds, have they fully taken into account the increased greenhouse effect from the un-condensed water vapour in the space between the clouds, the area of which is usually much greater than that of the clouds themselves... Comments?
  17. A Cloudy Outlook for Low Climate Sensitivity
    dana1981@34 Thank you. I am thinking on a global scale in regard to studies. 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. I agree. Uncertainty goes both ways. I acknowledge the upper end and the lower end when reading.
  18. A Cloudy Outlook for Low Climate Sensitivity
    "And of course there's always the 'warmer is better' mentality - I'm not sure if the Lindzens and Spencers subscribe to that, but many skeptics do." I don't know about Spencer, but his co-worker and co-religionist John Christy has definitely argued that warmer will be advantageous anyway.
  19. Extreme weather isn't caused by global warming
    #9: "Overall, I bet the so-called skeptics are drooling at the possibility of this coming to pass," JMurphy, you called it. Little did we know just how much drooling is going on. Here is RC reporting this story was a fraud: Coldest Winter in 1000 Years Cometh – not This claim circulates in the internet and in many mainstream media as well: Scientists have allegedly predicted the coldest winter in 1,000 years for Europe. What is behind it? Nothing – no scientist has predicted anything like it. A Polish tabloid made up the story. ... The “climate sceptics” website WUWT, noted for their false reports, takes up the RT piece, presents it together with The Voice of Russia and mentions „Mikhail Kovalevski“. Watts seems to be the bridge for the story´s crossing into the western media. And the stampede was led by the drooler-in-chief. Makes you wonder about just how the so-called 'Climategate' propagated so quickly, too.
  20. The human fingerprint in the seasons
    Oops. Here is the working link to the Kiehl/Trenberth paper.
  21. Renewable Baseload Energy
    @quokka: don't take the expression "sales pitch" negatively. You *are* engaged in pro-nuclear advocacy, so it fact you are selling nuclear energy to this audience. Also, you don't get to determine if you are right or not. That's not the nature of a debate - otherwise everyone would be right, as no one would claim to be incorrect. So you didn't "set the record straight," you argued for your position. Nothing less, nothing more. The "wasteful" arugment simply means you are using a finite resource (radioactive material) when not needed, while neither wind nor solar is finite (at least not for billions of years). Sure, some radioactive elements may be plentiful, but they still require a very complex (and thus expensive) process before they can be used (mining, refining, trasport, security, etc.). All of this adds up. Again, you fall in the same rhetorical trap as Peter Lang: by arguing that Nuclear is the *only* solution, you actually make it harder to sell. Think about it.
  22. A Cloudy Outlook for Low Climate Sensitivity
    Tim the Toolman #11 Er Tim, the stakes are our future. If clouds will save us, a lot of scientists will have egg on their faces. If clouds don't save us then vaya con Dios civilisation. Do you feel lucky?
  23. A Cloudy Outlook for Low Climate Sensitivity
    Camburn - you need to be more careful with your terminology. You said in comment #13 "There is really no evidence one way or another as of yet as to cloud feedback". That is flat-out wrong. In this article alone I discussed 4 studies providing evidence for a positive cloud feedback. You may not be convinced by this evidence, and I'm sure there have been a couple of studies providing some evidence for a small positive or negative cloud feedback, but there is most certainly evidence. And nobody is claiming the issue is settled. As Pete noted in comment #19, the article ends by saying "...much more research of the cloud-climate feedback is needed..." And of course a problem with the "don't regulate CO2 because the uncertainty is too large" argument is that uncertainty goes both ways. There's just as much likelihood that AGW will be majorly catastrophic as there is that it will be benign. Is it possible that a negative cloud feedback will save us from catastrophic warming in the near-term? Certainly. But it's also possible that a positive cloud feedback will drive us toward catastrophic warming in the near-term. Failing to act on the possibility of the latter in the hope that the former is true is extremely poor risk management. It's like driving around without auto insurance because you don't think you'll get into a car accident. Uncertainty is not the friend of the skeptic. The only reason not to act to reduce CO2 emissions would be if we are certain that their effects will be benign. As you clearly agree, we don't have that certainty.
  24. The human fingerprint in the seasons
    @RSVP: By their percentage contribution to the greenhouse effect on Earth the four major gases are: water vapor, 36–70% carbon dioxide, 9–26% methane, 4–9% ozone, 3–7% Sources: Earth’s Annual Global Mean Energy Budget Water vapour: feedback or forcing?
  25. The human fingerprint in the seasons
    66 (muoncounter), You seem to have tangled everything in knots as artfully as the most adept "skeptic." I suspect I introduced some of the confusion by using the phrase "initial forcing," which is redundant, and implies that a forcing is like a quick push. It's not. My intent was merely to distinguish the forcing from the feedback. A forcing is any change that alters the steady state of the system, changing (in this case raising) the equilibrium temperature. A feedback is a change to the system which results from the change in equilibrium temperature, but itself changes the temperature. A positive feedback is a feedback which enhances the initial change (i.e. changes the temperature in the same direction as the forcing). A negative feedback is a feedback which counteracts the initial change (i.e. changes the temperature in the opposite direction of the forcing). Our understanding of the climate system is that regardless of the forcing, there will be positive albedo, CO2 and H2O feedbacks. There may or may not also be cloud feedbacks, which could be positive or negative (we don't know yet). For a solar forcing to raise temperatures, TSI from the sun would need to have increased, and remain increased, just as CO2 levels must increase and remain increased. In no situation is there an "event" or "switch" or "restart" involved. The problem is merely, given a forcing, any forcing which is continuous and as such elevates temperatures, that forcing will be accompanied by strong GHG feedbacks (CO2, H2O) which will carry with them the same signature as a GHG forcing, and those feedbacks are roughly double the size of the initial forcing. This makes the statement that "a TSI forcing would not exhibit warmer winters and nights" false. That's all I'm saying. It doesn't prove or disprove anything. It's just not a valid argument.
  26. A Cloudy Outlook for Low Climate Sensitivity
    @Camburn: "Yes Pete. And since then we still havne't figured out clouds." Look at it this way: clouds may or may not lessen the impact of CO2 on warming. This does not put into dispute the actual CO2 impact, which is well-known. In other words, the uncertainty here is whether or not clouds will mitigate the warming, not if the warming will take place. To take a gamble on clouds that way isn't a rational position, it's wishful thinking (especially when the science tends to indicate they won't). To take my russian roulette example again, betting that clouds *might* mitigate AGW is like hoping that the gun should jam if you pull the trigger and get the bullet.
  27. A Cloudy Outlook for Low Climate Sensitivity
    @Camburn: "I am not possessed with uncertainty." Your posts tell a different story. To you, "uncertainty" seems to be reason for you to think the science is immature. It isn't, and uncertainty wouldn't be a sign it is either. "Does co2 play a factor in climate. Yes, to a small extent." Actually, CO2 is the main control knob of climate. There is ample evidence suggesting this is the case, and very little evidence supporting the idea that CO2 only has a small effect on climate. Or, to put it in a way you will understand, there is much greater uncertainty about CO2 having only a small effect than to the contrary. "Should we use CAGW as the reason to stop burning fossil fuels? Naw....the error bars with the models etc are not up to snuff to do so." That is your opinion, but it is not supported by the overwhelming evidence in favor of AGW. "I look at the science for what is has shown. I see the AGW science as infant and subject to an enormous amount of factors, some known, a lot to be learned. That is why you don't see the public engaged." Actually, the science is far from being in infancy, and the majority of factors are known. Again, you exaggerate how much we don't know. Furthermore, that is not why the public is not engaged. Mostly, the propaganda efforts of Big Oil, who tries to either deny the science, or muddy the issue so much it confuses people about the actual state of the science. As for the Carbon Tax, I think you are confusing this with Cap and Trade. The two are very different. Please explain to me how Goldman Sachs would make money with a Carbon Tax? At least you agree that we should transition away from fossil fuels, but that doesn't mean you are right about the state of the science. It's pretty clear to me that you're not.
  28. A Cloudy Outlook for Low Climate Sensitivity
    Yes Pete. And since then we still havne't figured out clouds.
  29. Pete Dunkelberg at 04:39 AM on 6 December 2010
    A Cloudy Outlook for Low Climate Sensitivity
    Camburn # 27 You found a 1997 paper: Zender, C. S., B. Bush, S. K. Pope, A. Bucholtz, W. D. Collins, J. T. Kiehl, F. P. J. Valero, and J. Vitko, Jr. 1997. "This article contributed by NASA's Distributed Active Archive Centers (DAACs.)"
  30. A Cloudy Outlook for Low Climate Sensitivity
    Archiesteel@24: I am not possessed with uncertainty. I read the papers for what they propose. This is a bit on and a bit off topic now: 1. Does co2 play a factor in climate. Yes, to a small extent. 2. Do we need to stop burning fossil fuels? Yes, emphatically. They are a finite resource that can't be replaced. 3. Should we use CAGW as the reason to stop burning fossil fuels? Naw....the error bars with the models etc are not up to snuff to do so. Should we use our heads and stop because fossil fuels are finite?.....YES....it is very easy to see that to any person with an ounce of brains. I look at the science for what is has shown. I see the AGW science as infant and subject to an enormous amount of factors, some known, a lot to be learned. That is why you don't see the public engaged. I have found this forum to be an interesting forum. I also see that some refuse to acknowledge how much we do NOT know. Just as the link I posted from NASA shows. Forget the carbon tax, that is foolish. Even Mr. Hansen thinks that is foolish. Investigate the origin of that idea. Goldman Sachs should come to mind. A money tree for them. There are solutions with proven tech to stop using so much fossil fuels. It is time to impliment them for the right reason: Fossil fuel is finite!
  31. Renewable Baseload Energy
    360 archiesteel I will repeat what I said above - If I think an argument is nonsense I will say so. If you think that is a "sales pitch" that's up to you.
  32. A Cloudy Outlook for Low Climate Sensitivity
    archiesteel@24: I hit the wrong key...it should have been: CAGW. Catastrophic AGW.
  33. A Cloudy Outlook for Low Climate Sensitivity
    We can play "what if" to our hearts content. I have stated that we don't know a lot about clouds. NASA seems to agree. http://earthobservatory.nasa.gov/Features/BlanketClouds/
  34. Ocean acidification isn't serious
    #24: "Coral bleaching is a vivid sign of corals responding to stress," Let's walk down your stress list point by point: a. increased (most commonly), or reduced water temperatures -- emphasis added b. increased solar irradiance (photosynthetically active radiation and ultraviolet band light) -- not happening, unless you live under an ozone hole c. changes in water chemistry (in particular acidification) -- yes, that happens when CO2 concentration increases and is the point of this thread c. starvation caused by a decline in zooplankton -- do they die due to lowered pH? d. increased sedimentation (due to silt runoff) -- local effects only e. pathogen infections -- chicken and egg here, increased stress leads to greater susceptibility to infection f. changes in salinity -- most likely local (we'd notice it globally) g. wind -- random, at best h. low tide air exposure -- sea level is rising i. cyanide fishing -- whatever that means So the winner is ... most commonly temperature, acidification "CO2 appears to be essential for coral photosynthesis?" Corals are Cnidaria ... (animals). We don't do photosynthesis.
  35. The human fingerprint in the seasons
    muoncounter #76 "Presumably you exclude heat that would otherwise be radiated " CO2 at best translates (skyward) the location of heat departure, but does not "retain" any more heat than its specific heat capacity allows. Here, two links to compare these values. http://www.engineeringtoolbox.com/carbon-dioxide-d_974.html http://www.engineeringtoolbox.com/water-thermal-properties-d_162.html Given that water vapor has double the heat capacity of CO2, and abounds in excess of 100 times the anthropogenic contribution in CO2, this retained "energy" you are talking about represents at most 0.5% of the total ambient. I suppose that is energy, but it doesnt seem like much.
  36. The human fingerprint in the seasons
    #77: "HR's point is... " If this: "either a solar or CO2 initial forcing will be accompanied by a strong H2O GHG positive feedback" was HR's point, it remains irrelevant until someone can explain the objections raised in #66. You cannot claim a point is valid if that point depends on a mechanism that is nonsensical.
  37. A Cloudy Outlook for Low Climate Sensitivity
    #22: "GCRs always reverse. But what if they don't?" GCR occurrence on earth is moderated by the interplanetary magnetic field; to a lesser degree by the earth's magnetic field. Thus the frequency of GCRs observed on earth is a 'magnetic field proxy,' which can be correlated with solar intensity. GCR intensity ended 2009 at a record setting peak and "early in 2010 the intensity decreased to 1997-1998 levels," where it remains through October 2010 (date of the report cited). The moral of that story: a solar min corresponds with a GCR max. We measure these things. For GCRs not to reverse (whatever that means) suggests that the sun will no longer cycle? And yet there are already signs of such a 'reverse'. "But if the solar factors align differently in the next 30 years," We can all play 'what if' ... if you like.
  38. The human fingerprint in the seasons
    65 (Actually thoughtful)
    we KNOW there is no notable solar input
    This is very true, but beside the point. The question is whether or not this particular argument is further evidence of a lack of solar input, and it's not. 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). The fact that part of the warming could come from a non-GHG forcing will only be evident in relative degrees of these effects, and there's no way to break it down (without a few hundred earths on which to experiment). HR's point is valid. It doesn't disprove AGW, but this particular argument for proving GHG forced warming fails.
  39. A Cloudy Outlook for Low Climate Sensitivity
    @Eric: GCRs aren't caused by the sun. You make a lot of long-term suppositions, which is fine, however we have to rely on the current data we have in order to speculate about the future, and the current data doesn't suggest anything but continued warming due to human activity, with a possible increase over that due to increased solar activity. I think skeptics are beggining to grasp at straws. That's the feeling I get reading these comment sections, anyway.
  40. A Cloudy Outlook for Low Climate Sensitivity
    @Camburn: why are you obsessed with uncertainty? The fact uncertainty exists is no reason for complacency. Say you are playing russian roulette: there is a lot of uncertainty as to whether or not the next shot will be the bullet. Does that diminish the risk in any way? The whole insurace industry is built on managing risk and uncertainty. The life of a professional poker player as well. You have to realize that uncertainty is no reason to dismiss the threat posed by AGW. (Oh, and by the way, what does GAGW stand for? It doesn't seem to be a popular acronym, as I couldn't find much when I googled it. Did you invent it?)
  41. Renewable Baseload Energy
    @quokka: "You can discount whatever you wish. That's your problem not mine." Actually, it's your problem, as you are the one engaged in advocacy. If people challenge your sales pitch, you have to take it into account, otherwise I and others who believe nuclear should be part of the solution are bound to re-evaluate their position. Your problem is the same as Peter Lang's (minus the insults, thanks for that): in your rush to dismiss renewables in favor of nuclear, you are actually doing a disservice to the latter.
  42. Stratospheric Cooling and Tropospheric Warming
    It's interesting to note but I did a search on a forum that I am a member of and now realize that I have been fighting this problem for almost four months. The thread is here: Original Thread But don't bother reading it. It's not necessary. Bob
  43. Pete Dunkelberg at 02:28 AM on 6 December 2010
    A Cloudy Outlook for Low Climate Sensitivity
    Denialism has been mentioned, and the "deny harder" response noted. But often and by no means only here, I get the impression that people in the climate area think of it largely in 19th century terms. To grasp this modern world one must be acutely aware of denialism as a set of rhetorical tactics. If you bring your concept of denialism up to date it becomes easier to see that we are dealing with industrial strength denialism.
  44. Eric (skeptic) at 02:26 AM on 6 December 2010
    A Cloudy Outlook for Low Climate Sensitivity
    In the Clement et al abstract: "This observational analysis further indicated that clouds act as a positive feedback in this region on decadal time scales." The observational analysis they refer to is a link from clouds to temperature and changes in large scale circulation. If we call the latter, X, it is obvious that X controls clouds which control temperature over the short run. In Lauer et al, they say "iRAM simulates mean clouds and interannual cloud variations that are quite similar to those observed in this region." How similar is "quite similar"? What about diurnal? And like the other paper, they are not considering X as a control on clouds which control SSTs and temperature in general. To be clear, my statements are about the short run, theirs are about the long run. But if the short run causation is circulation -> clouds -> temperature, then I don't think that a different causation is supported over the long run either. In a-detailed-look-at-galactic-cosmic-rays.html, Dana shows a "minor" influence of GCR on clouds, but shows that GCR doesn't explain warming, both correct conclusions for recent warming. The problem is that GCR can also have a major effect on the clouds in the short run which is always reversed because GCRs always reverse. But what if they don't? Obviously other long term factors can compensate, one of which is GHG. In How-we-know-the-sun-isnt-causing-global-warming.html Dana takes a "divide and conquer" approach to solar influences. That works for recent 30 years or so for which we have good data, but doesn't help for example for explaining the MWP. In short, a variety of natural factors plus CO2 warming explains the past 30 years. But if the solar factors align differently in the next 30 years, we could be looking at a situation in which a combination of solar factors negates or overtakes the GHG warming (e.g. increased GCR causing increased clouds, decreased UV causing more blocking, etc).
  45. Pete Dunkelberg at 02:17 AM on 6 December 2010
    A Cloudy Outlook for Low Climate Sensitivity
    Some people underestimate what climate models can do. But check comment 20 here.
  46. A Cloudy Outlook for Low Climate Sensitivity
    J Murphy@18: Thank you for the link. Again, I will state that the level of certainty in the models concerning clouds is not there. If you want to read papers that agree with your ideas as gospel, even tho the papers are 100% honest in their assesment of what has been learned, that is your perogative. After all, GAGW is still in the hypothosis stage and has not advanced to theory stage. There is a huge amount to learn about how clouds act/interact. On a global scale, there is nothing deffinitive as of yet.
  47. Pete Dunkelberg at 02:02 AM on 6 December 2010
    A Cloudy Outlook for Low Climate Sensitivity
    TimTheToolMan, This is a Model Intercomparison study, linked as usual to the appropriate data.
    Figure 1: Annual average TOA shortwave cloud forcing for present-day conditions from 16 IPCC AR4 models and iRAM (bottom center) compared with CERES satellite observations (bottom right)
    and not presented as definitive. Look at the last line:
    ...while much more research of the cloud-climate feedback is needed, he evidence is stacking up against those who argue that climate sensitivity is low due to a strongly negative cloud feedback.
    No study indicating sensitivity somewhat above 3 rather than below is a LOL unless you just don't care about the next generation, and Model Intercomparison Projects (MIPs) seriously contribute to our understanding of climate. These studies lead the various modeling teams to dig into the internals of their models and keep improving their physics of one climate process after another. I don't see any LOL in this picture.
  48. A Cloudy Outlook for Low Climate Sensitivity
    Camburn wrote : "There is really no evidence one way or another as of yet as to cloud feedback. There are suggestions going in both directions." Except there is far more evidence going one way than the other, as you can see at AGW OBSERVER : Papers on Cloud Feedback observations Papers on the Iris Hypothesis of Lindzen Anti-AGW papers debunked (including Spencer) But so-called skeptics prefer to stick with the lone voices, don't they ? Why IS that ?
  49. A Cloudy Outlook for Low Climate Sensitivity
    Daniel Bailey@15: 1. We all know that GCMs do not handle the h20 cycle well at all. 2. When I read a paper, I read the error bars and the certainty of the paper. 3. There are papers on both sides of the cloud sensativity scenerio. Non of the papers show, with a credible certainty, that clouds are well modeled yet. Hence the results are uncertain. Show me this evidence that is verifiable and not modeled, but observed. A small area of the world is a start, but we all know regional variances do NOT make climate.
  50. Renewable Baseload Energy
    356 michael sweet You can discount whatever you wish. That's your problem not mine. It is a fact that "nuclear does not do load following" myth crops up frequently. What I said was technically correct and setting the record straight. I also pointed out that grid specific modeling would be needed to determine at what proportion of total capacity nuclear would become uneconomic. It is clearly not minimum system demand. What is your problem with this? How come wind is less 'wasteful' than nuclear (whatever 'wasteful' means)? If wind has excess capacity that cannot be utilized because there is insufficient demand when the wind happens to be blowing, then without subsidy it is in exactly the same position as nuclear run at a low capacity factor - high capital investment being under utilized. Except that nuclear has the outstanding advantage of being dispatchable and reliable and able to perform the very important role of stabilizing the grid. As I said the 'wasteful' argument makes no sense to me and seems to be based on assumptions about how demand can be manipulated to match unreliable supply. You could make exactly the same arguments for reliable supply where demand is managed to a limited extent by off peak rates. I make no apology for the word 'bamboozled'. If I think an argument is nonsense, I will say so.

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