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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 101501 to 101550:

  1. The human fingerprint in the seasons
    Moderator, Thank you for the links to the Arctic. I visit Sea Ice on a regualar basis. I couldn't find current Arctic anomalies in the search engine. Just gave me past data. I put both in my favorites and can check them out to keep up-to-date.
    Moderator Response: [Daniel Bailey] Did a little more digging. Try this site: http://data.giss.nasa.gov/gistemp/maps/. Be sure to set the projection type to polar to then get the polar anomalies you seek.
  2. The human fingerprint in the seasons
    HumanityRules wrote:
    Muon when has the earth warmed and part of that trend did not include the effect of a GHG? To make it easier I'll give you any time in the past several hundred million years.
    So you are contesting with "since when have greenhouse gases haven't caused a greenhouse effect", aren't you? What is the purpose of your question and what has it to do with the seasonal trend? Are you implying that "all warming processes are made equal"? Certainly Physics doesn't change, but you know what are we really talking about.
  3. Ice data made cooler
    @RSVP As you were told, refrain for speculating if you don't know the subject. The figures were already given. If you want to have it correct you must research partial pressures and revise the simple arithmetic chain behind, as your "which means the ppm CO2 goes down, not up" shows you lost it at some point. Reading your paragraphs suggests that you suppressed some important information needed in the arithmetic chain and jumped to a conclusion. Research the web looking for that info, I won't offer that. @rest of the members I suggest not to provide basic information to those who, lacking the fundamental background and discipline, go fishing fundamental concepts using made-up assertions as bait. Please answer "you have ABC wrong, I suggest you revise DEF". It will suffice.
  4. The 2nd law of thermodynamics and the greenhouse effect
    Re #143 KR you write:- "Greenhouse gases absorb some of the outgoing surface IR" This leads to question 1/ Do GHGs emit out going radiation? question 2/ Do GHGs absorb radiation emitted by GHGs? question 3/ What calculation of emission and absorption by GHGs do you use to decide whether the temperature of a particular quantity of gas will increase or deacrease?
  5. How do we know CO2 is causing warming?
    scaddenp the basic physics is the laws thermodynamics plus the absorpotion spectrum of CO2. All very well understood already. The point I'm trying to make is that you can't experimentally measure greenhouse heating - you need the water vapour and temperature profile of the relatmosphere to do that, and that's experimentally impossible. Hence those demonised computer models.
  6. The human fingerprint in the seasons
    155 Muon "if greenhouse gases are causing global warming, we expect to see winters warming faster than summer". Muon when has the earth warmed and part of that trend did not include the effect of a GHG? To make it easier I'll give you any time in the past several hundred million years.
  7. Ice data made cooler
    Michael sweet #22 "releasing the same amount of both gases would substantially raise CO2 while leaving O2 essentially unaffected." CO2 solubility is around 4x that of O2. O2 in the atmosphere percentage-wise is around 500x that of CO2. For a 1 degree increase in water temperature you should have 125x the amount of O2 released. This means for every CO2 molecule you have 125 O2 molecules, which means the ppm CO2 goes down, not up.
  8. A Cloudy Outlook for Low Climate Sensitivity
    @Camburn: "There are 30 year cycles to climate." Really? I'm skeptical. Do you have any evidence to back this claim up?
  9. The Climate Show #3: Cancun and cooling
    Re: Bibliovermis I actually thought he was making a funny...
  10. The Climate Show #3: Cancun and cooling
    Umm... so? Is there a basis for that claim? If it is valid, why is it relevant? Please answer on a different page. There is a better area on this site for discussing the topic "it's cold somewhere."
  11. The human fingerprint in the seasons
    #151 muoncounter, From the article you linked me to. "The emergence of strong ice–temperature positive feedbacks increases the likelihood of future rapid Arctic warming and sea ice decline." In the next few years we will be able to determine if this theory is the correct one for the Arctic amplification. I will pay close attention to see if the sea ice extent goes below 2007 in the coming years. Hopefully it is not too late to make changes after a 5 year investigation period. Others are predicting a cooling phase that will lower temps until 2030. Do you know the webpage for current Arctic temp anomalies? When I look at this page most the Arctic (Canada, Alaska, Europe, and Russia look fairly cold). When I do a few spot temp checks like Yakutsk Russia or Yellowknife Canada they all seem below normal. Here is a link I look to daily to try and get a grasp of Global Temps in a quick view (unfortunately not anomalies though). Quick look at Global Temps.
    Moderator Response: [Daniel Bailey] This is a great resource for Arctic temperature info and trends. This is another great resource as well.
  12. The Scientific Guide to Global Warming Skepticism
    Superb work John, thankyou for this excellent resource. I'd perhaps have added a mention to Tyndall and Fourier, highlighting the depth of time that we have understood CO2 causing warming, but that is a trivial point in an otherwise lovely readable and informative resource. I'd like to secong Phil's request for an article on the "Warm Arctic, cold continents" weather pattern. Cold weather is rapidly becoming the latest denier meme in the UK as we face our second (or third, depending on your location) really severe winter in a row. There are some interesting research articles around on WACCo (like the acronym Phil!) and on the hypothesis of reduced autumnal sea ice causing cold mid-latitude winter conditions, see for example the Arctric Report Card 2009 - Atmosphere or Petoukhov and Semenov 2010. But additionally some suggest that the remarkably low solar activity may be the cause, e.g. Lockwood et al 2010, at least for Europe. Given the Russian winter of 2005-06 (a focus of the Petoukhov paper) and the widespread nature of the 2009-2010 cold, maybe the Lockwood example doesn't work hemispherically? I know it seems strange to ask an Aussie about Pommie weather, especially during the Ashes :), but this is the best site on the Web for resources linked to debunking false skeptic arguments, or providing links to the good science.
    Response: You had to bring up the Ashes, didn't you? As an Aussie and a (very) passionate cricket fan, that's an intenseful painful subject right now. If we win the 3rd Test in Perth, I may consider including WACCo in the next edition of the Guide.
  13. We're heading into an ice age
    Re: 180 Right next to the pictures of farmland and skyscrapers...
  14. The Climate Show #3: Cancun and cooling
    Well, at least Cancun seems to be cooling.
  15. Stratospheric Cooling and Tropospheric Warming
    mars at 09:40 AM says "When convection takes place the work is done by expanding the air parcel in the first phase of warming until this happens the air parcel will not ascend." Yes, the same as a cylinder compressing air, you apply work to the piston, squishing the air, the energy applied to the piston, is now contained in the air, as well as the prior existing energy is now more tightly compressed... now the rise... pushing up the piston, putting the energy applied by the piston back into the piston, until the air is back at equilibrium, with the same amount of energy contained in the volume of air prior to the compression. The same applies to the atmosphere, work is done, by energy being added to a parcel of air, the air rises, displacing the air above it(the piston) expanding, with the energy from the work being used to displace the air above, redistributing it into this, until it is at equilibrium with its surroundings... If the air didnt have more energy in it than the adiabatic rate dictated, it wouldn't rise, or less it wouldn't sink... So work goes both ways, it takes work to apply pressure/add energy... when it expands, it releases this energy, work is done, until it is at equilibrium. otherwise it would never stop rising, it would always contain more energy than the adiabatic rate dictates.
  16. We're heading into an ice age
    #179: I would say cool, but somehow that doesn't seem right. Did you notice they have an 'Ice Museum'? As in a place where someday children will go to see pictures of ice?
  17. We're heading into an ice age
    Re: muoncounter (175) Check out the video I linked in your comment. The Yooper
  18. The human fingerprint in the seasons
    Re: TOP
    "Yes, look at the graphs."
     OK, what should I be seeing?
    "Towards the end of November from 2008 on the temps are below normal till March or so the next year."
     Um, you mean the parts not in the middle of the range or warmer than the range? OK, just the colder, cherry-flavored parts, check. (To make this exercise easier, I've stitched the winter months of 2008-2009 into one graph, below) So, a laser-focus on the parts of the winter temps that you want to see (the tasty, cherry-filled parts) shows a portion of the winter was below the long-term variation. Check. Ignoring, of course, the unpalatable part of the winter in the normal range of variation and the very unsavory part warmer than the long-term variation. (Similarly, here's the winter of 2009-2010, below) Needless to say, most of this winter was simply too bitterly warm to eat. Good thing that jet stream was there to keep us cold, right?
    "Such anomalies can be just a few feet deep as anyone who swims in inland lakes can attest to."
     TOP, few "swim" in Lake Superior. Even the locals. Even at the height of summer it's simply too cold (those balmy top 6" rarely top 50 degrees or so). The fact that one can do a full-body immersion (I'm 6'-3") for hours at a time now is simply without comparison (twenty years ago I would not have dreamed of attempting this ever in my lifetime). That's why we locals usually swim in the inland lakes or where the streams meet Lake Superior (we know where the tide rips are; the "fudgies"/tourists don't, sadly and we lose a few every year).
    "I don't know if there is anything like Argo in Lake Superior, but the full depth is what needs to be looked at, not just the top few feet."
     Yikes! You mean all 1,332 feet deep? Valuable stuff will get frozen off... Seriously, TOP, that's why we use baselines and anomalies. To measure the deltas. Which show this area is warming. Including Lake Superior. If you want to find correlations that actually exist, look at the droughts of the past few years relative to the long-term records or run the local temperature record for the past few winters and correlate it with the Arctic Oscillation. You'll find local weather here is colder during the negative phase. OK, fun's wearing off now. Lemme know if you find a statistical correlation on that AO thingy. The Yooper
  19. A Cloudy Outlook for Low Climate Sensitivity
    dana1981: I look forward to discussing Dessler's paper. dhogaza: There are 30 year cycles to climate. 1/2 of that cycle is 15 years. That is why the 15 year temp criteria. The reason for the 95% is that is the significance level of HadCrut temp data. That is stated in the literature. I did not pull that out of thin air. Back to clouds again. No comment on Sun's paper at all?
    Moderator Response: [Daniel Bailey] If you are going to respond to archiesteel at 133 below with links to sources, per the Comments Policy, please provide a summary of what you think the linked reference means in support of your position. Thank you!
  20. It hasn't warmed since 1998
    The new images here should remove any doubt that those still clinging to the 'it hasn't warmed since 1998' mantra are truly in deep denial. The above is temperature anomaly for the period 2000-2009. The clincher is the companion image, both available full scale here, which represents 1970-1979, when things were a lot bluer. Be sure to check the color scale.
  21. It's cooling
    82: "Iris effect" Good catch, Yooper! Now that's one I hadn't heard of. So off to the google machine: I suppose NASA's Revisiting the iris effect is old hat, but it does offer up a great one line come-back to the pretenses of the cherry-picker: “You cannot make a scientific judgment,” Wong said, “until you’ve done the complete analysis.
  22. Stratospheric Cooling and Tropospheric Warming
    Joe Blog at 22 Re Para 3 When convection takes place the work is done by expanding the air parcel in the first phase of warming until this happens the air parcel will not ascend. The air parcel once it starts to rise continues to do so because it is less dense than the surrounding air mass but as it rises the external pressure is lower and therefore it expands. The process is adiabatic that means no heat is added or taken away from the system during the ascent phase. To put it another way the same amount of heat in a large space translates to a lower temperature. Physically due to gravity the heavier air parcels fall to the bottom of the atmosphere and the lighter rise. The colder air having been displaced downwards is now at a higher pressure and therefore its temperature is higher but again this process is adiabatic so no work is done, and yes heat does accumulates at higher levels during the day but of course it is lost again during the night. The bit I am not sure about is whether this is agreement with Joe or Tom.
  23. The Scientific Guide to Global Warming Skepticism
    I LOVE it! Very useful. And... has anyone worked out a daily-life example for the statistical probability that all these ominous numbers are random, perhaps in terms of poker? Such a thing could be a vwonderful grand finale for your list. For example, see Larry Gonick and Woollcott Smith's immortal book, The Cartoon Guide to Statistics? They open the chapter on testing hypotheses with a legal example about racial bias... I'm skipping the calculations here... in which the cartoon lawyer concludes triumphantly that the chances of getting an 80-person jury panel with only 4 African Americans work out to about .0000000000000000014. "Is that a small number or a big number?" says the judge. The lawyer explains, It's less than the chances of getting three consecutive royal flushes in poker. So the judge rejects the hypothesis of random selection, confiding to the reader, "If I was in that poker game, I'd a started shootin' after the second royal flush..." Yeah. Keep up the good work. Elise
  24. The human fingerprint in the seasons
    @107 Daniel Bailey Yes, look at the graphs. Towards the end of November from 2008 on the temps are below normal till March or so the next year. This is about the time the jet stream moves south cutting off the flow of warm air from the south. Warm air comes up from the South to warm even the UP. Current NWS climate summary CF6: [TEMPERATURE DATA] AVERAGE MONTHLY: 17.4 DPTR FM NORMAL: -3.8 HIGHEST: 29 ON 1 LOWEST: -3 ON 9 And the record high was a surface temperature in August, not in December. The article states, "highest average surface temperature ever, a balmy 68.3°F." Such anomalies can be just a few feet deep as anyone who swims in inland lakes can attest to. I don't know if there is anything like Argo in Lake Superior, but the full depth is what needs to be looked at, not just the top few feet.
  25. It's cooling
    Yup, still happening: NASA: Hottest November on record, 2010 likely hottest year on record globally — despite deepest solar minimum in a century And the zonal means plot showing the polar amplification: Zonal Means Plot for November 2010 Don't know about you, hoss, but this cowpoke says the heat is on... ...but I still feel significantly lucky! Iris effect, anyone? Bueller? The Yooper
  26. How do we know CO2 is causing warming?
    VTG - to demostrate the basic physics of the greenhouse effect, no it doesnt. For the real atmosphere, you can just measure the effect directly but most people dont have access to satellites or appropriate instruments. Henry - it can be harder than you think to get this right. What wavelength really is that warming lamp emitting cf to the spectral sensitivities that you want? Water will mask the CO2 effect. Better to use two bottles and do simultaneously (otherwise you might be just measuring a difference in conduction heating between your two times). Have bottoms of bottle black and irradiate with normal sunlight or strong lamp. Need to think very carefully about your setup to eliminate conductive effects.
  27. A Cloudy Outlook for Low Climate Sensitivity
    dhogaza #129 - Yes, Dessler discussed the well-established water vapor feedback in his paper, as opposed to the much more uncertain cloud feedback. We'll discuss that in the blog post on his paper. Besides which, there is a large body of empirical evidence that climate sensitivity is 2 to 4.5°C for 2xCO2. I agree, the speculation that there will miraculously appear a negative feedback just in time to prevent dangerous warming levels is wishful thinking.
  28. A Cloudy Outlook for Low Climate Sensitivity
    Camburn: "Thank you dana1981. If 2010 ends with temps of statistical importance, I will agree. It is pretty plain and simple." What, in your mind, makes 1995 as a starting point more meaningful than 1994? Other than the fact that cherry-picking 1995 allows for the claim that since that date, significance onlyr reaches 93% rather than 95%. So, what's your non-cherry picking scientific reason for picking that date? Also, 95% significance for publication etc has been more or less picked out of a hat by statisticians, there's no theoretical basis for that number, and indeed some fields typically accept less significance, while others require much higher significance. Statistics are a tool, and the 95% level is a guideline, nothing more. Fisher (the Godfather) talked about this quite a bit, he'd be the last in the world to insist that >=95% confidence means "true" while <95% means "false". Such claims are just bullshit.
  29. A Cloudy Outlook for Low Climate Sensitivity
    "The cloud issue seems to be the most mysterious of all the factors. No clouds or water vapor feedback and a doubling of CO2 gives a 1.2 C warmup." However the water vapor feedback is well-established, with solid observational data from space backing it up. There's nothing going on with temp trends to make one believe that we're observing a significant negative feedback today from clouds, and the arguments that we will magically see such a negative feedback kick in at just the right time to stop further warming, based on dubious speculation, seems like wishful thinking to me.
  30. Renewable Baseload Energy
    Actually thoughtful, Thanks for the information. We get a mixture of sun and clouds in the summer. From what you say it sounds like systems are being developed. We will have to see how economic they turn out to be. I have heard a lot about GSHP.
  31. Ice data made cooler
    TOP: Yes. Units are not optional. My next version will address a variety of needed display features that you and others have pointed out. Great suggestion on albedo. When I was adding the Methane graph, I thought I should scale it according to it's added greenhouse effect, and then do the same with CO2. I didn't get around to it, but your suggestion on albedo brings the issue to the front. I should try to show a variety of feedbacks. Any one know of a data set with this type of information? One clarification: Do you mean, where albedo is low, more solar radiation is absorbed and reradiated at infrared; and with high albedo, more solar radiation is reflected back into space? jg
  32. A Cloudy Outlook for Low Climate Sensitivity
    Thank you dana1981. If 2010 ends with temps of statistical importance, I will agree. It is pretty plain and simple. Good question as to what causes cloud cover to change during the ENSO cycles. There is no question that it does. Finding the cause is more difficult. Has anyone read Sun's paper?
  33. actually thoughtful at 05:23 AM on 11 December 2010
    Renewable Baseload Energy
    Michael Sweet - I would like to know the insolation levels during the summer - does the heat come with notable cloud cover? Here is an overview of the idea: http://en.wikipedia.org/wiki/Solar_air_conditioning#Solar_thermal_cooling (also look at the desiccant bit higher on the Wikipedia page). One possibility I would examine is a ground source heat pump (GSHP) and PV to balance out the solar load (in other words, after the GSHP reduces the load by ~75%, use PV to supply the electricity to run that GSHP compressor). You can't put enough PV on a rooftop to natively provide AC or heating (too much load). But once you apply a renewable strategy to eviscerate the load, you can use PV or residential wind to mop it up. Note this strategy relies on "grid banking" - putting more in than you use for 6 months of the year, balance for 3, and withdraw for high summer. If your house is well insulated, you might over-cool the house during peak solar (9-5 (summer)) and let it slowly warm through the evening (this is only to match PV output to AC load - it doesn't serve any other function, and may not be desirable when you look at the whole picture - I am keeping us relevant to the original post...). The cheapest "solar cooling" is evaporative cooling - little application in FL, but huge in the southwest (although it ought go hand-in-hand with rainwater harvesting so as to not stress water supplies).
  34. Ice data made cooler
    JG I would like to see units. Just something my profs drove into me from day one. There is insolation and there is albedo. Where the albedo is extremely low the energy will be retained at the surface and not re-radiated. Where the albedo is moderate to high the insolation energy will try to get back out by radiation. Is there some way you can show albedo at various latitudes over time?
  35. A Cloudy Outlook for Low Climate Sensitivity
    I think it's a waste of time arguing with Camburn over the statistics here. He's clearly demonstrably wrong in many ways, and he's clearly not going to admit that he's wrong. I know we try to avoid the term on this site, but I'm sorry, that's denial. It's not relevant to this article anyway, so I suggest we just let Camburn have his denial and move on. For the record though, Chris G is correct that the generally accepted confidence level of 95% is quite arbitrary, not that it matters since the temperature trend is statistically significant at this level, whether Camburn will admit it or not. Spencer's hypothesis seems rather bizarre to me. Cloud cover is what controls ENSO cycles, yet ENSO cycles generally happen on a pretty regular basis. So what then is causing cloud cover to change on this regular basis? Wait, let me guess - 'natural cycles'?
  36. It's not us
    Continuing a reply to a comment here. "if one presupposes that human activity in some way affects the temperature of the Earth" Let's think of some things that human activity affects that we might agree on. I won't bother to provide citations for these things; you can find them quite easily if you want: a. ozone - remember that 'hole' that we could close by restricting CFC use? b. smog - air pollution controls have successfully reduced smog problems (caused in part by auto exhaust) in Los Angeles. Look also at successful pollution controls in central Europe put in place in the early 90s. c. acid rain - caused by SO2 emissions from industrial activity, reduced by scrubbers. d. dust clouds/storms - over farming in the US dust bowl; coal-fired power plants and urban pollution in Asia. e. CO2 -- there are a lot of studies measuring 'urban CO2 domes' that are directly tied to daily, weekly and seasonal traffic patterns. Of course, there is all that annual CO2 input from fossil fuel consumption. f. clouds - we know how to 'seed' clouds and make rain, at least in limited areas. How many of these human activities 'affect the temperature of the Earth' in some way? Some might say they all do. Here's what the experts say (I've quoted this a number of times and will continue quoting it wherever necessary until John says enough): Weather in a given region occurs in such a complex and unstable environment, driven by such a multitude of factors, that no single weather event can be pinned solely on climate change. In that sense, it's correct to say that the Moscow heat wave was not caused by climate change. However, if one frames the question slightly differently: "Would an event like the Moscow heat wave have occurred if carbon dioxide levels had remained at pre-industrial levels," the answer, Hansen asserts, is clear: "Almost certainly not." The frequency of extreme warm anomalies increases disproportionately as global temperature rises. "Were global temperature not increasing, the chance of an extreme heat wave such as the one Moscow experienced, though not impossible, would be small," Hansen says.
  37. We're heading into an ice age
    #174: "I'm not the one expecting that warming should be linear." Great! That means you admit there is warming going on, which promotes you out of the 'four legs good, two legs bad' 'no, its not' crowd. "if one presupposes that human activity in some way affects the temperature of the Earth." I'll go out on a limb and guess that you don't. There are many threads that more appropriate; you should look at them and see how well your opinion holds up. I'll continue this comment here.
  38. A Cloudy Outlook for Low Climate Sensitivity
    Camburn... Please inform us as to what 93% does not cut it and why? I mean, if you're going to cut down the data set to present a conclusion that falls just short of statistical significance you need to back that up with a meaningful reason why you do so. If there is no specific reason for choosing the 1995 to present data set then, since is falls short of statistical significance for either warming or cooling, then you need to pull back and add data to the set. Pull back until you get a statistically significant data set. Back to say, 1990. Then what do you find? If you absolutely must have 95% confidence or better then you need to use enough data to get to that confidence level. Do this and you absolutely will find unequivocal warming.
  39. There is no consensus
    @NQoA: what's your point, exactly? That we should trust experts on a particular matter because there's relatively few of them? I know deniers usually aren't motivated by logic, but you sir take the cake.
  40. We're heading into an ice age
    @NQoA: I think your point is that you're going to disbelieve the science, whatever it says, as long as it does not conform to your preconceived notions about the reality of AGW. "I'm not the one expecting that warming should be linear." Nor is anyone who understands the science, despite what you seem to be insinuating. Stop trying to set up that strawman argument, no one's buying it. "I didn't miss anything, I was pointing out that the AGW team - up until recently, promoted the expectation that the ice sheets and glaciers would continue to recede" They have, when you look at it globally. Of course, when you engage in such cherry-picking as you've demonstrated, that doesn't really matter, does it? Is that what skeptics have been reduced to? I remember when we had quality opponents, such as BP - not amateurs such as NQoA who still try to say it's not warming...
  41. Renewable Baseload Energy
    Actually Thoughtful, I live in Florida. It is about 94F every day in summer and about 80F at night. Can solar be used to cool the home in these conditions?
  42. A Cloudy Outlook for Low Climate Sensitivity
    Camburn, In addition to what others have posted, if you are going to use statistics, you might as well try to understand what they mean. A 93% confidence means that there is a 93% chance that the observed pattern is 0.93 likely to have not been caused by the inherent variation of the data. That leaves 0.07 for the chance that it is, which in this case, means that at the time the test was made, your statement that "we have not warmed for the past 15 years" had a chance of being correct of 0.07. So, if you are not willing to choose a course of action based on a 0.93 chance of warming, I don't see why you would expect anyone to choose a course of action based on a 0.07 chance of no warming. Yet, that is what you are proposing. Why is that? Nevermind that in the larger context, the window of time that you have chosen to take a stand on is only a fraction of the time for which we have plentiful information about, and the rest of it supports the 0.93 probability position. Lastly, the 5% rule is not really golden; its pretty arbitrary.
  43. Guest post: scrutinising the 31,000 scientists in the OISM Petition Project
    Re: NQ/A (108) That depends. If you are asking me to prove the non-existence of something (which would be a silly request), then I could not do that. Scientists follow the Scientific Method:
    1. Define the question 2. Gather information and resources (observe) 3. Form hypothesis 4. Perform experiment and collect data 5. Analyze data 6. Interpret data and draw conclusions that serve as a starting point for new hypothesis 7. Publish results 8. Retest (frequently done by other scientists)
     The hypothesis that is best supported by all of the data is the one that gains eventual acceptance by other scientists. Over time, an accepted hypothesis can be verified sufficiently to become a theory. That is where the field of global warming is: Theory. Per the National Academy of Science in their publication Advancing the Science of Climate Change:
    "A strong, credible body of scientific evidence shows that climate change is occurring, is caused largely by human activities, and poses significant risks for a broad range of human and natural systems…. Some scientific conclusions or theories have been so thoroughly examined and tested, and supported by so many independent observations and results, that their likelihood of subsequently being found to be wrong is vanishingly small. Such conclusions and theories are then regarded as settled facts. This is the case for the conclusions that the Earth system is warming and that much of this warming is very likely due to human activities."
     “Very likely” means a greater than 90% likelihood of probability. I.e., pretty certain. So, in order to overturn the anthropogenic attribution of global warming, what must a scientist do? Find a viable physics-based alternative to one of the points in this chain:
    1. Increasing the level of a greenhouse gas in a planet’s atmosphere, all else being equal, will raise that planet’s surface temperature. 2. CO2 is a greenhouse gas. 3. CO2 is rising. 4. Therefore (given 1-3 above) the Earth should be warming. 5. From multiple converging lines of evidence, we know the Earth is warming. 6. The warming is moving in close correlation with the carbon dioxide. 7. The new CO2 (as shown by its isotopic signature) is mainly from burning fossil fuels. 8. Therefore the global warming currently occurring is anthropogenic (caused by mankind).
    Plenty have espoused alternative theories on blogs, but none have been able to survive scrutiny in a peer-reviewed publication. So have any scientists, using all of the data, been able to break the above chain? None that I'm aware of. Fossil fuel interests spend hundreds of millions of dollars in the US every year to lobby against any controls on fossil fuels and CO2 emissions. Vast riche$ await anyone who can scientifically break the chain of evidence & show the AGW is a non-worry (I'd chip in a couple of hundred myself). Spencer is probably the closest to a competent scientist among the denialarati. Per the Dessler/Spencer emails, Spencer believes clouds cause ENSO... So the real question is: have you found any scientist that claims to have overturned AGW? If so, who was it? In what peer-reviewed publication was their work published? Have they presented their proof to those meeting in Cancun yet? I have no wish at all for AGW to be real. You have no idea the amount of sleep I've lost over the years because of it. The thought of the world I bequeath to my young children and their children... NQ/A, with the caveat that this is a hypothetical question for thought purposes alone and answering will not constitute an admission of belief in AGW, if AGW is real and all of the predictions come true, what will you say to your grandchildren when they come to you and ask you what you did to try and stop it? Just curious. The Yooper
  44. A Cloudy Outlook for Low Climate Sensitivity
    Norman the disagreement is specifically on ENSO, not generally on warm/cold ocean less/more clouds. It's stated explicitly by both Spencer and Dessler, it's ENSO that causes less clouds or less clouds that produce ENSO? The former mechanism is straightforward, the latter is really misterious and not even guessed by Spencer himself.
  45. A Cloudy Outlook for Low Climate Sensitivity
    #115 syphax, I went to the link you posted (RealClimate). I read the posts below and it is the same I read everywhere including this site. Many questions and a lot of opinions but still no real solid undebatable answers. CO2 will produce warming of the Earth. How much is the big unknown. The cloud issue seems to be the most mysterious of all the factors. No clouds or water vapor feedback and a doubling of CO2 gives a 1.2 C warmup. That is about the only number I see given that most agree to (both camps). On the cloud issue I believe Spencer's view has a logical basis. The observation is less clouds and a warmer ocean. One conclusion feels a warmer ocean produces less clouds, another feels that the fewer clouds warm the ocean (more direct solar radiation gets absorbed). If not for clouds the Earth's total albedo would be around 0.15 and the Earth would be much warmer (The albedo calcualtor indicates about 20F). With clouds the Earth's albedo is 0.3. So some types of clouds may warm the Earth depending upon the thickness, the location and the time of cloud development (night clouds keep the night from cooling as much, thick day clouds in the summer greatly reduce the high temperature, anyone can get this information from personal observations), but overall clouds must cool the earth because of their overall effect on albedo.
  46. How do we know CO2 is causing warming?
    henry justice @226 Problem is, the bottle would need to be as tall as the atmosphere, in order to mimic the pressure gradient. And be perfectly insulated. And be wide enough to allow convection without wall effects. And be connected to a series of other bottles to mimic heat transport through the atmosphere to different latitudes. etc. Let us know how you get on with that one.
  47. Stratospheric Cooling and Tropospheric Warming
    Oh and tom, there is a thread over at Science of Doom about this stuff.
  48. Stratospheric Cooling and Tropospheric Warming
    Tom Curtis at 13:23 says "Specifically, while it only takes a few hours to restore thermodynamic equilibrium in the atmosphere by conduction, it can take as much as 50 days to do the same by radiation." Again, the reason for this, is the opacity, radiation, is an inefficient mover of energy in the lower layers of the atmosphere, where it is opaque, because what is radiated, is absorbed in a very short distance. As the atmosphere thins with altitude, the path length shortens, radiation travels further before it is absorbed. When air convects, it looses its energy, performing work, displacing the air above it, this energy is put into the air it is displacing, this is why it cools... Now if radiation wasn't moving this energy, out of the upper layers of the troposphere at the rate convection was carrying it there, the energy would accumulate. And because energy is still coming into the system, it would lead to a build up of energy in the system, raising the T at all layers. And it would continue to do this, until it had heated the higher layers(shorter path length) up enough until they were radiating the energy away. Convection, cannot take energy out of the system, it does not work in a vacuum. And energy cannot be created or destroyed, it can only come into the system, via radiation, and leave via radiation. If more is coming in, than what is being radiated away, the system will accumulate energy, until it can radiate the incoming away. You are violating, the first law of thermodynamics. For your second point, the same applies, it dosnt matter that at the surface, it is warmer and radiating more, because the energy is simply swapping between molecules, This is why convection occurs, energy accumulates... In the tropics, it receives a lot more energy from the sun than at the poles, there is vastly more water vapor in the atmosphere, to much higher levels(due to convection)... again making the atmosphere opaque to radiation, inhibiting it. Causing convection to much higher altitudes, until the energy can be lost via radiation. The bottom line is, if convection was moving more energy up to the tropopause, than what was being radiated away, it would heat, moving the tropopause up, until it got to a level, that it could radiate the energy away. You have to be able to explain, where your energy is? It doesn't vanish. Now if there was no solar absorption in the upper atmosphere, we would have a T gradient, starting from the surface T, and decreasing until the outer layer at 2.7K The back ground T o space.
  49. Guest post: scrutinising the 31,000 scientists in the OISM Petition Project
    Daniel - I'm curious, in your opinion, are there any "competent scientists" that do not believe in AGW?
  50. We're heading into an ice age
    muoncounter - I'm just wondering, what do you think my point was?

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