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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 106651 to 106700:

  1. Common graphical tricks and the Medieval Warm Period
    Mark, Great post, it would be nice to include the deception used on page 34 of the (perhaps soon to be withdrawn) Wegman Report. Reference http://rabett.blogspot.com/2010/10/dummys-guide-to-strange-scholarship-in_17.html
  2. Do critics of the hockey stick realise what they're arguing for?
    Sordnay #25: "Just wondering, on your first graph, is CRUTemp NH, but what is exactly this serie? a 12 month mean of CRUTempNH does not rise more than 0.657" You're looking at anomalies calculated from different baselines. Same data, different 'zero point'. "Anyway, looking again to the first figure, the recent temperature anom. would be about the same as the drop estimated from around 1480-1550 (eyeballing) without a net forcing and in time period somewhat similar to recent anom, a bit higher. What is the reason for this drop?" Cherry picking. You've looked at the noise and picked out the highest peak and lowest drop. Shifting 20 years earlier or later yields radically different results (indeed, the temperature INcreases). Judging by figure 2 the ~1550 drop appears to have been caused by volcanism. The ~1480 peak could have been due to any number of weather factors... like the large up and down swings between them which invalidate the entire premise that this was some sort of trend comparable to the current warming.
  3. It's not bad
    hi jmurphy I have already said I know they are not mutually exclusive. That is really not what i am saying. What I am saying is the sea runing out of fish by overfishing may be a more pressing issue than AGW/CC as it may affect humans more and first. Don't you think this is equally as big an issue? Do you think overfishing receives less coverage even though it is just as important as AGW/CC. Maybe it is more important. Do you know? Does anyone know? Has this been raised before on this site - does this mean it is being overshadowed?
  4. Throwing Stones at the Greenhouse Effect
    #75 "The difference between direct radiation into space and radiation that eventually reaches the same place having bounced around our atmosphere a bit first is the measure of that delay." We experience delays in communication systems daily. These may last two seconds at the most. Are you trying to say that two more seconds of lingering heat after the Sun sets is causing global warming?
  5. Throwing Stones at the Greenhouse Effect
    doug_bostrom #76 "Would you mind naming just one element, compound or mineral found on Earth that is not capable of emitting IR?" My reference to "materials that do not emit IR" is like speaking about people with no brains, or as you say, the "slow-witted". Since you have read my earlier posts, you know very well I was referring to the relatively lower emissivities of N2 and O2. At any rate, to answer the question, IR is can only be emitted from the surface of things, all else is incapable of this, which just happens to make up about 99.99999% of the Earth's material. Hope this helps.
  6. Roger A. Wehage at 22:08 PM on 20 October 2010
    Record snowfall disproves global warming
    Below is a scatter plot of the monthly snowfall in Houghton, Michigan by year prior to 2010 as given here.
    From Climate Change
    The data shows a relatively uniform amount of snowfall in the months of October and November across the 120 year span. In these months the lake would generally be warmer and not frozen over, so evaporative moisture would be available, but temperatures more likely to be too warm for snow. Then in December, January, and February the monthly snowfall steadily increases as the years get closer to 2010, but only up to a point. These would be the months of colder temperatures and partially to fully frozen lake surface. As John pointed out, less snow tends to fall in extremely cold temperatures, and in this case, less snow also falls when the lake is frozen over. So in the far out years both extremely cold temperatures and frozen lake were likely to have occurred more often. In intermediate years of higher snowfall, the temperatures started to moderate and the lake froze over later, allowing more evaporation and more opportunity for substantial snowfalls. Then the plot shows significant declines in monthly snowfall in these months from around 1980 to present. Most significant are the months of January and February. My guess for this is that the lake had little ice in December, allowing more evaporation, and the temperatures were periodically cold enough to allow substantial snow and other times rain. Then the lake partially froze over in January and February, reducing the evaporation rate, and the temperatures were sometimes ideal for snow and at other times for rain. The trends for March and April snowfall are less clear over the 120 year span. However, both months do appear to have a peak around the 1980 timeframe where the total annual snowfall peaked. These snowfalls were probably less associated with lake effect than with ideal snow conditions. In those years when the lake had significant ice, melting probably didn't start until May.
  7. It's not bad
    hapivibe wrote : "I have no data. I am telling you what i see but i hope you will allow me to write what i see as it doesn't say all comments must be backed up by data anywhere on this site, does it?" Of course you don't need data for everything you write but you did come on here suggesting that there was an obsession with data and AGW, to the detriment of those other causes you mentioned. Now, it would appear that you don't actually have any proof of that - it is just your observation of this site and what you see in the real world ? Well, we can all use our own experiences to come up with our own opinions (especially with regard to AGW, over-fishing, the destruction of the rainforests, etc.) but those opinions are more credible and reliable when they are based on some form of fact, evidence, data, etc. I don't need to directly experience any of those to generally accept that the problems exist and need to be faced sooner rather than later. Anyway, have you looked at the Intermediate version of this thread ? There are more linkages (and links) given there between AGW and all the causes you mention, showing that they are not seen in isolation or as mutually exclusive and separate. There is also more at Can animals and plants adapt to global warming?, and Comparing what the IPCC and peer-reviewed science say about Amazonian forests
  8. It's not bad
    Hapivibe - I should have further explained what a sea urchin barren is - when the sea urchin populations increase to such an extent they strip the shallow coastal waters of kelp and other seaweeds - hence a barren seascape.
  9. It's not bad
    Hapivibe - that's true - let me expand. what i mean is we can't see into the sea to see it's health or how depleted it is - it's pretty mysterious as we only see the surface I'm now in my 4th decade of diving. I live in New Zealand. I can tell you the sea life is diminishing. Overfishing is responsible for the spread of sea urchin barrens here, because the main predator, crayfish (spiny lobster) and snapper, populations have plummeted. The effects of nutrient run-off (nitrates & phosphates predominately) and siltation are also apparent in inner harbor waters. New Zealand is often trundled out as a poster child for sustainable fisheries management. I shudder to think what is happening in other parts of the world.
  10. Throwing Stones at the Greenhouse Effect
    One of the ways you can see the greenhouse effect at home is simple. Take a remote temperature sensor (IR) and point it skyward on a clear day or night and on a cloudy day or night. The clear sky (absolutely no visible clouds) will register -50F or lower. The cloudy sky will register in the 30F range. The same sensor pointed at the sun will not register much different. This is why you have dew fall at night and ice on the windshield in the morning when the air temps are above freezing. At least in my area the really hot weather (hot and humid) comes in the summer when hot, humid air from the GOM blows in. The heat in this air is imported from the Gulf by horizontal convection (wind) and remains hot day and night. Much of Europe would be much colder if it wasn't for heat transfer by way of horizontal convection in water (Gulf Stream) and then wind blowing that heat to cover the land. This is the general picture of the greenhouse effect, not to be confused with the particular picture the OP is saying skeptics hold, that the greenhouse effect due to CO2 doesn't exist.
  11. Throwing Stones at the Greenhouse Effect
    Miraculously, even though temperatures during the year can get far below zero, somehow due to this process energy is mysteriously accumulating. A miracle to the slow-witted, perhaps, but not for those who understand that temperature is expressed on a continuum, not as a binary state, that while a thing may still be said to be cold, it may yet be warmer than in times past. If so, it can only be doing so in the materials that do not emit IR, not in those that do. Would you mind naming just one element, compound or mineral found on Earth that is not capable of emitting IR? If you can't, will you promise to always listen carefully? AGW depends on this pin ball machine model where the IR is bouncing around as if lost and unable to escape. Amazing how close you can get to surrendering and admitting you understand this process, while still eluding the final moment of capture. For this I must be burned at the stake for "throwing stones". No fear, not only does nobody see you as a fitting candidate for martyrdom, all you need do is wish different physics into being and you'll be entirely impossible to ignite.
  12. It's not bad
    that's true - let me expand. what i mean is we can't see into the sea to see it's health or how depleted it is - it's pretty mysterious as we only see the surface. not sure why i said we don't live near the sea, that was a mistake. i meant we are not close to the drift nets, for example that plunder it. we don't see that. re. rainforest i really mean amazon rainforest. is the rainforest close to you reducing in size or is it protected?
  13. It's not bad
    i propose that the rainforest and the sea are far away from westerners who comment on this site. Illustrating the hazards of assumptions, we live about 5 miles as the crow flies from the sea, about 40 miles from a temperate rain forest.
  14. It's not bad
    cool doug and dappled. i feel better that it's not just words xx ahhh!!!please, no kisses on this site, it's for proper scientists don't you know! scientists need love too : - ) ?
  15. It's not bad
    Well, hapivibe, to me "would have thought" sounds kind of like "assume." We all know what "assume" means. I can tell you that in my case we have a bit of computer gear here that necessarily runs all the time, having to do w/offsite backup. Problem, eh? Especially it's a problem because while the local climate means that a little less than 90% of our juice comes from hydro, the same climate means that photovoltaic systems are not affordable for much more than crosswalk flashers and things on that scale. What does work here is domestic hot water preheat via solar collectors, so I installed a system that eliminates a substantial amount of electrical input for hot water heating, thus indirectly eliminating about twice the electricity consumed by the 24/7 computer hardware. What's great about the DHW thing is the knock-on, catalytic effect it had on some of our other behaviors around the house. The absolute consumption (~1000kWh/year) of the computer hardware versus the DHW output reminded us of how just a few extra things turned off add up over time. In my mind, turning off unnecessary load sort of equates to more sunlight on the solar collectors. Strange, but that's psychology. Meanwhile, this next couple of years will be most interesting because we've got two automobiles that are arguably ready for retirement. They've reached 20+ years of age and while they're in good repair and don't have the lousiest gas consumption, we're finally at the point where buying an electric vehicle is no longer going to be a technology application experiment folded into day-to-day living. Given our typical requirements for driving, this means we'll shortly no longer have to purchase gasoline except in those rare instances when we decide to rent a IC car for road trips. A big win there. That leaves as usual the problem of air travel, the huge, airy elephant in the room. This is a nice example of how we're embedded in context and the dilemmas that can pose. While many of my relatives in the U.K. are dead, some are not. They are sort of a case of an "endangered species" but all the same I have qualms about visits. We go over that way about every 3 years on average, which is definitely not sustainable when we generalize and consider the hundreds of millions of aging aunts and the like pining for visits from nephews, grandchildren, etc. That's a toughie, it's an inheritance and difficult to just turn off.
  16. It's not bad
    hi jurphy thanks for getting back to me and thanks for your interest: i think the smoking analogy has gone off topic a bit so i wont reply directly to that i propose that the rainforest and the sea are far away from westerners who comment on this site. species extinction does not affect us directly nor are we told when we are consuming more than our fair share and it is sadly only a minority of people take direct action to change things. global warming is a more frightening concept as it may affect all of us indiscriminately and therefore is has captured the imagination of people as an issue and it may get more media coverage due to this pscychological aspect than the other issues i proposed. I have no data. I am telling you what i see but i hope you will allow me to write what i see as it doesn't say all comments must be backed up by data anywhere on this site, does it?
  17. It's not bad
    Hapivibe @ 44 - Also, if fossil fuels are running out, does this timing coincide nicely with the need to reduce the use of fossil fuels? Easily accessible oil may be running out, but there's plenty of coal, tar sands and shale left. Enough perhaps, to turn the Earth into a rather different looking planet. Finally, I would love an assurance that the people on this site putting masses of effort into collating data and facts actually live in a sustainable way ie. you practice what you profess Yup, but by no means an "eco-saint". It's a very long list of practices my wife and I undertake to reduce our carbon output, but I don't judge others badly because they don't put in the same effort. Hopefully we'll all get there in the end (fingers crossed!)
  18. Roger A. Wehage at 20:36 PM on 20 October 2010
    Record snowfall disproves global warming
    I believe that here is an excellent example of what John is describing related to temperature effects on snowfall. Below is a plot of the annual snowfall in Houghton, Michigan listed in tabular form on the above website.
    From Climate Change
    Houghton's snowfall is primarily influenced by moisture from the lake (lake-effect snow) and temperature. The graph clearly shows three trends, a relatively constant annual snowfall from 1890 to around 1935, an increasing annual snowfall from around 1935 to around 1980, and decreasing annual snowfall from around 1980 to 2010. I don't have access to average annual winter temperatures, but it is likely that average winter temperatures were colder between 1890 through the 1930s and have been rising steadily until today. Assuming the above, then during the colder years from 1890 to the 1930s the lake likely froze over earlier and thawed later, allowing less moisture to evaporate into the air and reducing lake-effect snow. From the 1930s to around 1980, as winter temperatures increased, the lake started to freeze over later and thaw earlier, allowing more moisture to evaporate, which increased lake-effect snowfall. After around 1980, as temperatures continued to rise, more of the moisture was likely falling as rain, so the average annual snowfall started decreasing again.
  19. Throwing Stones at the Greenhouse Effect
    Graham... "greenhouse effect slows down the radiative transfer through GHGs re-radiating LWR" IR travels at the "speed of light", some 3 x 10E8 meter per second. Maybe you can explain where the delay is coming from? More relevant to what you mention, you can model the spinning Earth as getting hit with a heat pulse. Temperature rises and falls. Your CO2 affecting the droop, such that it doesnt get as low with less CO2. Miraculously, even though temperatures during the year can get far below zero, somehow due to this process energy is mysteriously accumulating. If so, it can only be doing so in the materials that do not emit IR, not in those that do. AGW depends on this pin ball machine model where the IR is bouncing around as if lost and unable to escape. I believe warming is happening, but I do not believe it is happening for the reasons you do. For this I must be burned at the stake for "throwing stones".
    Moderator Response: The delay is simple to explain, so simple that I believe you already understand it but refuse to stop digging. However, for the sake of completeness, the delay is the same as in any journey - if you take a detour or backtrack, the journey takes longer. The difference between direct radiation into space and radiation that eventually reaches the same place having bounced around our atmosphere a bit first is the measure of that delay. The rest of your post is of a standard consistent with your first, and I decline to indulge your contrarianism any further.
  20. It's not bad
    hapivibe wrote : "I know the issues are not mutually exclusive - I am proposing that they get overshadowed." And what is the basis for your proposal ? In what way do you think those issues are being overshadowed ? Is money, effort, etc. being taken away from those issues in some quantifiable way ? What's your evidence ? By the way, my previous analogy of the doctor telling you about cancer or the health-damaging effects of smoking (while being a smoker him/herself) did not involve HIM/HER having lung cancer - it involved them telling you about the detrimental effects on your life from smoking, especially if it had caused YOU to develop cancer. Would you ignore/disregard that doctor's opinion or diagnosis just because that doctor was doing something that he/she is advising you not to (anymore) ?
  21. It's not bad
    Hi dappled water I know the issues are not mutually exclusive - I am proposing that they get overshadowed.
  22. It's not bad
    Hapivibe @ 44 - Destruction of the rainforest which is needed for species diversity Destruction of the rainforests will also negatively impact the climate. The Amazon alone has between 86 to 93 billion tonnes of carbon locked up in it's vegetation and soils. Our oceans are being overfished And acidified too, from the combustions of fossil fuels. Which will affect fish populations at some point. So, as you can see, these issues aren't mutually exclusive.
  23. It's not bad
    Hi to JMurphy: I would be pretty miffed if my doctor had lung cancer and continued to smoke. to doug_bostrom the amount of activity this site has means that people are really bothered by this issue(s) and I would have thought that people would want to take further, bigger action towards sustainablility than just writing on web site and I am wondering if this is the case.
  24. It's not bad
    Witnessing myriad discussions focusing on whatever shreds of countervailing evidence are available as alternative explanations for what is at root a fairly simple, bulky and ultimately powerful process leaves me completely unsurprised that you find discussions here dominated by minutiae, hapivibe. Bloating the importance of little things by employing large rhetoric is the sharpest tool in the kit of people who for whatever reason wish to ignore the CO2 problem. You're absolutely right that we're imposing a heavy load on the systems we depend on. Getting a grip on the CO2 problem is a key part of not further exacerbating our failure to account for our impact on the planet. More, there's little reason to believe that solutions to the problems you mention are somehow mutually exclusive, rather it's probably reasonable to suggest that integrated approaches would be more beneficial. As you suggest, apathy is our enemy, an old human failing seemingly only overcome in moments of crisis. Looking at the various graphs of depressing facts, what's the largest contributor to fossil fuel GHG emissions? Coal is the most abundant and presently active feedstock for CO2. There's plenty of coal and we're burning more of it than ever. We're not going to run out of coal fast enough to rely on depletion of fossil fuels as a solution to CO2 emissions. There's no data so far indicating we're going to stop burning coal. Depletion as a solution to CO2 emissions on the timescale of concern here seems a dead-end. Your demand for assurances about sustainable living is of course impossible to answer affirmatively, either for "the people on this site" in general or you yourself. In communicating via this site you and I and the rest of the gang here are employing a myriad of devices and systems that are not presently built or operated in a sustainable way. What some of us may be able to say is that we try to be mindful of those occasions as are available-- in the context we find ourselves living-- which afford choices regarding making more or less of a mess. Come to think of it, your demand for pledges of sustainability is rather curious. What is it that you think "people on this site" profess? I'm wondering, do you believe that subscribing to mainstream physics and the scientific method in general is some sort of statement of moral superiority? Perhaps I misunderstand, though.
  25. It's not bad
    hapivibe wrote : "Finally, I would love an assurance that the people on this site putting masses of effort into collating data and facts actually live in a sustainable way ie. you practice what you profess." Why ? Would you disregard the opinion or diagnosis of a doctor who smokes, especially if you were being told that your cancer was caused by smoking ? Or if you were told to give up smoking because it is badly affecting your health ?
  26. It's not bad
    The amount of debate an attention to minutiae is unbelievable on this site. It is good in a way but I am curious as to why the issues on this site evoke more discussion than almost anything else I can think of. The possible downsides to this arguing about AGW/climate change are that it overshadows other very important issues that affect people and planet. Other issues that are important irrespective of AGW are: Destruction of the rainforest which is needed for species diversity Our oceans are being overfished We use too much of the world's resources on average per person Species extinction Political apathy resulting in necessary change not happening quickly enough Also, if fossil fuels are running out, does this timing coincide nicely with the need to reduce the use of fossil fuels? Finally, I would love an assurance that the people on this site putting masses of effort into collating data and facts actually live in a sustainable way ie. you practice what you profess.
  27. Do critics of the hockey stick realise what they're arguing for?
    51.dana1981 Thanks for the condescending reply but at least it directed me to some useful info which was what I really wanted. http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter2.pdf So this basically confirms what I said was correct. From section 2.8.5.3 (Efficacy and Effective Radiative Forcing - Solar) "These studies have only examined solar RF from total solar irradiance change; any indirect solar effects (see Section 2.7.1.3) are not included in this efficacy estimate." Section 2.7.1.3 rates the scientific understanding of some of these possible indirect effects as low and very low. Let's not mention what the Haigh paper might do to all this. The incorrect statement here is your suggestion that we can't have it both ways. Having it both ways is still an option until we fill the gaps in our knowledge. Which is all I've been arguing here. I thought the concluding statement about volcanic RF in section 2.7.2.2 was also enlightening. "Because of its episodic and transitory nature, it is difficult to give a best estimate for the volcanic RF, unlike the other agents. Neither a best estimate nor a level of scientific understanding was given in the TAR. For the well-documented case of the explosive 1991 Mt. Pinatubo eruption, there is a good scientific understanding. However, the limited knowledge of the RF associated with prior episodic, explosive events indicates a low level of scientific understanding" I wonder just how many bold staements one can make on this subject.
  28. Throwing Stones at the Greenhouse Effect
    gpwayne #72 "no interest in" (facts) Would you be just a little concerned if the fan on your CPU died? Why isnt radiation sufficient to cool that big chip? Or if you happen to burn you finger, why not just point it skyward? No, you put it in water because the fact is, convection provides a faster channel to dump energy. Our lives are governed by facts, even if we are successful living off of hype.
    Moderator Response: [Graham] Your straw argument does not pertain to climate change or the planet's energy budget, primarily because it is the current speed with which equilibrium is reached that determines the acceptible limits of our climate (acceptible being what we are used to, what we humans have come to depend on, what we know sustains our agriculture etc). The absence of convection does not preclude heat transfer by radiation, in the same way the absence of water vapour does not inhibit the movement of LWR through a gaseous medium such as a mixture of oxygen and nitrogen. The speed of the transfer is, in fact, the point at issue, because the greenhouse effect slows down the radiative transfer through GHGs re-radiating LWR at specific wavelengths in random directions, thus impeding the direct transfer of heat back to space.
  29. Do critics of the hockey stick realise what they're arguing for?
    chriscanaris #56 The risk is that if we make unwarranted assumptions that a number is large and negative, if it's small, or positive then we will end up basing policy on a false premise. If you don't want to be seen to be trotting out unsupported climate sceptic talking points, then you need to be more careful in the way that you express yourself ;).
  30. Do critics of the hockey stick realise what they're arguing for?
    kdkd: 'Your strategy suggesting that we should account for this unobserved large negative feedback mechanism would seem unnecessarily risky...' What's the risk? '...assuming that it might provide a get out of jail free card seems unwarranted.' Who said it was get out of gaol free card? Not me.
  31. Throwing Stones at the Greenhouse Effect
    KR at 15:06 PM on 20 October, 2010 Yes, it is proof of a transition, not of the greenhouse effect itself. Im a believer in accuracy in these things is all. Its not my call end o the day. But it seems a simple alteration, to: evidence of an enhanced greenhouse is etc... as e said. But ill say no more on the matter ;-)
    Moderator Response: [Graham] Joe - I too think your point is valid and accurate, but it does seem to me a rather arcane point for the basic version. I always struggle with these posts, trying to walk the fine line between brevity and over-simplicity. In this case, since the distinction is clearly addressed in the intermediate version and I can't figure out how to qualify my remark without expanding into more explanations (and qualifications) I've elected to leave it as it is. I do acknowledge your comment however, and agree you are strictly correct.
  32. Jeff Freymueller at 17:31 PM on 20 October 2010
    Increasing southern sea ice: a basic rebuttal
    #8 HumanityRules, for starters, refer to Is Antarctica losing or gaining ice? at another page on this site. And then remember that the Wingham et al paper figures are for ice in the interior 72% of the ice sheet and not at the coastline, which is where by far most of the mass loss occurs (from the second page of the paper: "we extend an earlier survey (Wingham et al. 1998) in space to within, on average, 26 km of the ice sheet margin"). So the "throw away line" is correct, and your position reflects where things stood some years ago, not today.
  33. Throwing Stones at the Greenhouse Effect
    Well, The Inconvenient Skeptic expressed some dismay at the entire thrust of the rebuttal, saying "I am not aware of anyone saying there is no greenhouse effect... This article seems intentionally written to insult people that disagree with the theory that the currently increasing CO2 is going to significantly alter the Earth's climate." So I am obliged to RSVP for providing evidence that, far from this being some kind of intentional - and fictitious - slight aimed at skeptics, even on this site we are obliged to address posters who don't understand the greenhouse effect, energy budgets, radiation, heat transfer or the role of GHGs - while these same posters feel they are able to take issue with the scientific complexities of AGW. Thanks also to those more patient than myself, who took the time to explain some basic facts to a poster I suspect has no interest in them (to judge by the amount of time he spends here, and how little he has absorbed while doing so).
  34. Increasing southern sea ice: a basic rebuttal
    I know this is mainly about sea ice but the throw away line about land ice has to be countered. Wingham et al in 2006 found the land ice mass balance increasing 1992-2003. http://www.cpom.org/research/djw-ptrsa364.pdf In fairness my own position would be that antarctic data is so short term, sparse and difficult to interpret that it seems foolhardy to make any sort of definitive comment about antarctic land ice trends. This 2007 Science review by the same authors is well worth a read if you want to get some perspective. http://www.ucl.ac.uk/es/department/news/2007/wingham-science.pdf
  35. Do critics of the hockey stick realise what they're arguing for?
    so there's clearly a good reason to study the role of clouds in forcing feedback, but assuming that it might provide a get out of jail free card seems unwarranted. That is all.
  36. Do critics of the hockey stick realise what they're arguing for?
    chriscanaris #52 All I'm saying is that making strong conclusions about cloud feedbacks, and climate risks is unwarranted from that paper. Meanwhile the bulk of the information available to us suggests that any negative feedback from clouds won't be big enough to remove the anthropogenic forcings. Your strategy suggesting that we should account for this unobserved large negative feedback mechanism would seem unnecessarily risky
  37. Do critics of the hockey stick realise what they're arguing for?
    Phila @ 50: I'm not saying, 'Things won't be that bad.' I'm saying, 'There are many things we don't know which we really need to know.' I certainly think what we know is sufficient to warrant action and I have said so often enough. In my professional life, I'm no stranger to the need for decisive action in the face of major uncertainty. I have to explain this uncertainty to people - indeed, if I failed to do so, I would expose myself to a malpractice suit. Moreover, I prefer being honest with my clientele (it actually feels better doing things that way). At the same time, I certainly want to know more whether it's in my professional life or in an area of interest.
  38. Throwing Stones at the Greenhouse Effect
    If some skeptics were right in claiming the greenhouse effect had indeed been falsified, then that would apply to the greenhouse effects of water vapour and methane as well as CO2. Sorry to point out the obvious, but any high school kid can demonstrate the greenhouse effect of water vapour simply by correlating overnight minimum temperatures with cloud cover. An example of this simple exercise is provided on my web site (www.climatechangeanswers.org/science/homedemo.htm). (My apologies to the better informed skeptics, but outright denial of the greenhouse effect has to dealt with forcefully)
  39. Do critics of the hockey stick realise what they're arguing for?
    kdkd: Wide error bars arise because of limited information. Do you prefer making decisions based on limited information by artificial foreclosure or would you prefer informed decision making in the context of acknowledgement of uncertainties? Would you rather everyone decided to treat clouds as an inconvenient distraction or would you prefer to see climatologists striving to understand their role better? Eyeballing the AR4 graphic, the cumulative aerosol and cloud albedo effect even *without* the error bars actually approaches the CO2 effect. This is not trivial. The size of the error bars in this context highlights the urgency of the need for better data and better understanding.
  40. Do critics of the hockey stick realise what they're arguing for?
    Humanity Rules #40 - I suggest you do some reading on efficacies of different forcings. The aforementioned (and linked) climate sensitivity rebuttal is a good starting point.
  41. Throwing Stones at the Greenhouse Effect
    In your rebuttal it might be worth adding that, as Tyndall and others have proved in the laboratory that CO2 absorbs infrared radiation, the onus is well and truly on the skeptics to prove that CO2 behaves differently in the atmosphere. This is how I worded it on 22 Sep 2010 in my article Climate Change: The 40 Year Delay Between Cause and Effect: "There should be no dissent that CO2 absorbs infrared radiation, because that too has been demonstrated in the laboratory. In fact, it was first measured 150 years ago by John Tyndall using a spectrophotometer. In line with the scientific method, his results have been confirmed and more precisely quantified by Herzberg in 1953, Burch in 1962 and 1970, and others since then. Given that the radiative properties of CO2 have been proven in the laboratory, you would expect them to be same in the atmosphere, given that they are dependent on CO2’s unchanging molecular structure. You would think that the onus would be on the climate skeptics to demonstrate that CO2 behaves differently in the atmosphere than it does in the laboratory. Of course they have not done so."
  42. Throwing Stones at the Greenhouse Effect
    @DSL Very good point. "Seriously, take a little time off and study radiative transfer and what happens to incoming solar radiation when it hits the various surfaces of the earth system." The albedo of the ocean is microscopic when compared to the land or clouds. In other words the ocean absorbs almost all the radiation that hits it. So what keeps it so cool? Water is the ultimate greenhouse liquid. There are minor forcings to this effect like plankton, wind and the angle of the sun's rays. Most likely it is not radiation back into space, it is evaporation (phase change) and convection. The heat is re-radiated into space from the upper levels of the atmosphere when the water vapor changes phase back to water. That's why you can see the tracks of hurricanes in the ocean surface temperatures for a time after a hurricane passes. Mess with evaporation and you really do have a problem.
  43. Do critics of the hockey stick realise what they're arguing for?
    chriscanaris: I'm not into bargaining (and by implication, denial). I'm getting weary of repeating that I believe rising CO2 very likely heralds warming and that our society should aim to decarbonise. Bargaining doesn't imply denial, as I see it. It implies a preliminary acceptance of a situation, coupled with an unwillingness to face the full implications of that situation. My impression is that you keep saying, in effect, "maybe things won't be all that bad," without offering much in the way of a cogent defense for that position. Again, uncertainty in itself does not provide rational grounds for optimism. Furthermore, I suspect that the scientists who are counseling immediate action actually have a far better grasp of the relevant uncertainties than dilettantes like you or me. Recognizing what we don't know is important, granted. But recognizing what we do know is important, too. Waiting for the science to get "better" is a pretty irresponsible gamble, IMO, especially given that the plausibility of AGW being much less serious than we think seems to rise in inverse proportion to one's actual expertise.
  44. Throwing Stones at the Greenhouse Effect
    Joe Blog - Actually, having less energy leaving than arriving is exactly what is happening. The various feedbacks and systems (ocean temperatures, in particular) have a time lag to changes in forcings, and are still approaching equilibrium. While that is occurring, there will be a net imbalance at the top of the atmosphere. The climate doesn't react instantly - there's always a lag to respond to forcing changes. And positive feedback doesn't indicate a runaway situation unless the gain is >1, as has been repeated discussed here.
  45. Do critics of the hockey stick realise what they're arguing for?
    Chris #47 For prudence, one should take the midpoint of a value between error bars for your estimated parameter value, unless there's good evidence to suggest that the error bars are somehow wrong. In which case the error bars should be revised to be narrower. Unless there's assessment of greater uncertainty. As a good guess, one should take ±1SD of the error bars as being 66% likely and ±2sd as being 95% likely, with ±3 SD as being 99.8% likely. Attempting to draw strong conclusions by assuming that the true value is between -3 and -2 SD (approx. 17% likely = (99.8-66/2) ) is a fools errand. This appears to be what you're doing. The paper you referred to was merely indicating that the current estimate of the size of the error bars is very wide, which is an entirely different proposition.
  46. Do critics of the hockey stick realise what they're arguing for?
    An excellent article, John. Confronting skeptics (who won’t listen) and the general public (who may listen) with the logical consequences of skeptics’ claims is potentially an effective alternate line of rebuttal. I don’t think you need to complicate the article by discussing the evidence for a global or local MWP. The global temperature reconstructions in Ned’s article posted on 28 Sep 2010 are broadly in line with the reconstruction you have used here, so your argument still holds. The climate sensitivity to a particular greenhouse gas (CO2, CH4 or whatever) is the temperature rise resulting from a doubling in concentration of that greenhouse gas. The value of the radiative forcing corresponding to the doubling is not part of the definition. Your wording: Technically, climate sensitivity is defined as the change in global temperature if the planet experiences a climate forcing of 3.7 Watts/m2 (which is how much climate forcing you get from a doubling of CO2). Suggested alternate wording: Technically, climate sensitivity is defined as the rise in average global temperature resulting from a doubling of atmospheric CO2. (The added radiative forcing from such a doubling is 3.7 Watts/m2.) The text “then current climate change must also also natural” should read ““then current climate change must also be natural”.
  47. Throwing Stones at the Greenhouse Effect
    Joe, I think you make a valid point, but consider that this post is meant as a "basic" version of the argument. Technically speaking, the short term decrease in outgoing radiation is evidence of an enhanced greenhouse effect, not a greenhouse effect in general. It's an important distinction to make, but I think it's a bit too pedantic for a basic version of the post. If you take a look at the intermediate version of this post, you will notice that this distinction is spelled out more explicitly.
  48. Do critics of the hockey stick realise what they're arguing for?
    kdkd: The whole point of the paper is that there is a lot we don't know and a lot we need to find out. Recognising the limitations of our knowledge is the sine qua non for progress in science. AR4 however does provide an estimate of cloud and aerosol feedbacks relative to other forcings including an estimate of uncertainties for both cloud, aerosol, and CO2 forcings. While I don't regard AR4 as the Holy Grail of climate science (there is no such thing in any science), I think it's a reasonable starting point.
  49. Increasing southern sea ice: a basic rebuttal
    This might belong under the intermediate version, but thinking of the complexity... It's pretty clear that less ice in the winter, (as mentioned in the article), when it's dark, would have negligible warming effect because albedo doesn't play a factor when it's dark. However, to add to what GT just wrote, if there is more ice at the beginning of the melt season, I'm thinking that will be a negative feedback to regional warming. I'm not saying it will be stronger than the other effects; I'm just thinking it will exist and wondering how it will all add up.
  50. Do critics of the hockey stick realise what they're arguing for?
    chriscanaris #45 Without wading through the detail of the Stephens 2005 paper, it doesn't seem to be offering any information on the order of cloud feedbacks relative to other climate forcings. As a result the paper quite rightly does not offer strong conclusions about the sign and magnitude of climate sensitivity itself, but defers this to other literature. From looking at the paper, it does not offer any justification of the strong claims that you are trying to make.

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