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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 110701 to 110750:

  1. Pielke Sr and scientific equivocation: don't beat around the bush, Roger
    HR@1- "Given the choice is now between Willis and Trenberth who's expert opinion should we trust?" Hey, everybody makes mistakes, but now that you bring up this very issue, in your appeal to authority: Correcting Ocean Cooling "That February evening, Willis says, he was updating maps and graphs with the data that had become available since the 2006 ocean cooling paper was published. He was preparing for a talk he had been invited to give at the National Center for Atmospheric Research in Boulder, Colorado. The topic was “Ocean cooling and its implications for understanding recent sea level trends" He was looking at a map of global ocean temperatures measured by a flotilla of autonomous, underwater robots that patrol the world’s oceans. The devices—Argo floats—sink to depths of up to 2,000 meters, drift with the currents, and then bob up to the surface, taking the temperature of the water as they ascend. When they reach the surface, they transmit observations to a satellite. According to the float data on his computer screen, almost the entire Atlantic Ocean had gone cold. Unless you believe The Day After Tomorrow, Willis jokes, impossibly cold." “Oh, no,” he remembers saying. “What’s wrong?” his wife asked. “I think ocean cooling isn’t real.”
  2. Pielke Sr and scientific equivocation: don't beat around the bush, Roger
    SN Ratio @ 4: BP hasn't even posted a comment yet (and may or may not want to) and you say a priori that you won't take him seriously. Sorry, guys, but 'superstition' kind of also fails the civility test. I really don't want to see this thread degenerate and drag this site down to the lowest common denominator (pun intended :-) ). Graham, whether Pielke Sr is right or wrong is one issue. However, he returned fire with fire. I also don't think it's fair to suggest HR is 'studiously avoiding the issues.' He's addressed them pretty clearly and directly as best as I can tell. Whether he's right or wrong is again a separate issue. But let's not get caught up in a ****fight. For what little it's worth,I actually think you do owe Pielke Sr an apology. I don't think you really need to agonise about it - all of us sometimes have to do it. You also need to be charitable to those with whom you disagree. Labels dehumanise and impute bad intentions where sometimes none exist.
  3. Pielke Sr and scientific equivocation: don't beat around the bush, Roger
    I read the article that Pielke snr linked to in his reply: http://pielkeclimatesci.files.wordpress.com/2009/10/r-334.pdf He is skeptical about the IPCC for its emphasis on CO2 and long range computer modelling and some of the findings of James Hansen and associates. This is based on ocean heat measurements by Joshua Willis over a 4 year limited time frame. He is saying that ocean heat is the most reliable measure we have of global warming because the ocean is the largest reservoir of heat change. Hence, ocean heat change measured in joules is a superior measure to average surface temperature. He concedes that 4 years is a narrow time frame. All he claims in that article is that it raises issues about our level of understanding. He raises other points about other contributors to climate change and prefers to take a regional approach rather than rely on unreliable global average metrics. These are the sort of points that scientists ought to be discussing about this issue. He asserts that: "Humans are significantly altering the global climate ..."
  4. Pielke Sr and scientific equivocation: don't beat around the bush, Roger
    I tend to agree about the need for weighing words in characterizations better. But, at the same time, it is really hard to take Pielke, HR (plus BP here) quite seriously. Looking at the historical data, there is clearly a rather low signal-to-noise ratio here, which means that heat content may be suddenly "increasing" (like after 2000), only to "decrease" slightly for several years thereafter. And both Pielke and HR simply fail to draw the only sensible conslusion from the data: Avoid talking about short-time trends when the inherent variance renders such measures wildly variable. Necessitating longer observation periods. In the case of OHC, we also have a rather simple giant-scale thermometer in sea level, and that has turned out to be a much better indicator of warming than most direct temerature estimates. Any claims about warming or not warming must be checked against the basic set of indicators. Failure to do so, in my view qualifies for "denialist" or "warmist" characterizations. And in particular, to qualify as a skeptic, I have to always be on the conservative side in quality and precision assessments. Thus, for example, rather go with well established long time trends, and give up on catching eventual trend shifts early on. Drawing wide-ranging conclusions from sparse and rather crude data, looks more like superstition to me - I really can't see what that has to do with skepticism.
  5. Pielke Sr and scientific equivocation: don't beat around the bush, Roger
    Scientists like Pielke have a responsibility not to put dangerous myths into the hands of those whose interests are very different from that of the majority. As do journalists :-)
  6. Pielke Sr and scientific equivocation: don't beat around the bush, Roger
    Well, you did accuse him of 'denialist spin,' which in most circles would pass as an ad hominem comment. You say you're just a journalist writing about science. And I'm just a psychiatrist looking at a human interaction played out in the blogosphere. While Pielke Sr's intense reaction is a backhanded compliment to the influence of this site, it's also a reminder that we need to observe basic civility in our dealings with folks. On this occasion, I'm afraid your presentation would have got anybody's back up. I'll let HR tackle you on the science - he's better at it than I am :-)
    Moderator Response: [Graham] I agonised over this during the last 24 hours. Should I remove the remark and apologise in a footnote? Was it really lacking in civility? I made my decision. My remark stands because I don't think it is uncivil, I think it's calling a spade a spade (and compared to Joe Romm, I'm almost a fan of Pielke's). I also find the indignity expressed on this issue - what you call 'an intense reaction' - reminds me of the standard diversionary tactics I see all the time in debates like this. And in no circles would a remark about denialist spin pass as an ad hom unless it stood without any substantiation. I've now written over 3000 words on this issue, of which that remark was a single line. My remark is not an ad hom - it is an ideological association based on Pielke's record.
  7. Pielke Sr and scientific equivocation: don't beat around the bush, Roger
    gpwayne "indignant" really? You should reread his post and your post and note how many times each of you refer to the other authors emotional state, ideological outlook or ulterior motives, it should be obvious who's taking this personally. The NODC near realtime update of OHC shows that the oceans haven't been warming since 2004ish. This is based on the best data available to us. It's less than perfact but the best we've got. We have to make the most of that. Kevin Trenberth can't believe the ARGO data because he is unwilling to question the quality of his own data. It's a common fault with all flavours of scientists. It doesn't mean he's wrong but it does mean we have to take this good scientists word with a pinch of salt. Josh Willis also took part in the email exchange published on Pielkes website, He looks like the real expert on ARGO to me. Instead of simply critising the data he has been willing to accept errors in the ARGO data and actively sort to correct them. His feelings now on the data is that it's now robust and unlikely to see any future large corrections. Given the choice is now between Willis and Trenberth who's expert opinion should we trust? You haven't dealt with Pielkes main reason for being interested in this subject. The fact that good quality OHC data would be a far better metric for measuring global warming than air temperature. It seems he makes that point over and over again not because the short term trend suits his outlook but because of specific features of the climate system. If you truely want to have a scientific discussion with Pielke snr you should try addressing that issue.
    Moderator Response: [Graham] It seems to me that you are studiously avoiding the issues being discussed. You keep trying to move the debate towards something else - the validity of various metrics or the emotional nature of certain remarks - and away from the following: Pielke says the ice wasn't melting, the oceans were not heating and the sea has not been rising. And building on this array of claims for which there is plenty of evidence to the contrary (or insufficient evidence to make any claims at all), he makes the statement that global warming stopped during this period. It is these claims, the unequivocal nature of them, and the lack of rigour inherent in such assertions, that is under discussion, not issues surrounding measurements or analysis.
  8. Climate and chaos
    thingadonta - can I suggest you move this "models arent reliable". The source code for models are public domain; a massive literature covers them. What you state is valueless FUD without some evidence to back your assertion of bias unconscious or otherwise in the models. Actually I do think there is one bias in the models - that they accurately reflect known physics.
  9. Climate and chaos
    No, thingadonta, mathematicians did not redefine the concept of chaos based on their own field's "assumptions." Researchers discovered a phenomenon that exists in nature, and reused a common English word as its label, but in doing so they clearly specified its precise meaning in that technical usage. The opposite frequently happens as well--clearly defined scientific terms often become lay terms with much less clearly defined meanings.
  10. A detailed look at climate sensitivity
    crunz246, in addition to the links scaddenp provided that directly answer your questions, you should also see the more general post CO2 Is Not the Only Driver of Climate.
  11. Climate and chaos
    re 9 Tom Dayton I'll try and keep out assertions of ill intent. However, researcher bias is well-known, its not necessarily deliberate or conscious, its largely unconscious/assmumptive, and it includes experiments/models being affected by the researchers themselves not only in selection and design, but also as the experiment/model proceeds. "The key aspect of chaos is that minor changes in the starting conditions cause big changes in the local/near-term trajectory of the system" I always thought chaos was deined as a system in continual instability/flux, not just at the starting point, but ongoing, at the 'edge of chaos' so to speak. Such is also the argment for tipping points as a system proceeds. I fail to see why it should only apply at initial conditions. I had just writte the above when I checked and found that wiki actually states that mathematicians only define chaos are dependant on initial conditions (http://en.wikipedia.org/wiki/Chaos). Ah, those mathematicians are at it again-re-defining concepts based on the own field's assumptions; but wiki does mention, in passing, that this definition is done "ignoring the effects of the uncertainty principle"-which most scientists know is pervasive, ongoing over a the course of time or model or experiment, and can't actually be 'ignored' to suit assumptions in a model.
  12. A detailed look at climate sensitivity
    crunz246 - see Climate's changed before Intermediate version. You are probably also interested in CO2 lags Temperature In short - CO2 isnt the only forcing in town - its just the one causing the current warming.
  13. A detailed look at climate sensitivity
    And could someone please explain to me one time why in all the ice core data we never see temperature continue to rise when CO2 "catches up" with it on a chart. I mean logic would tell you that if the feedback thing was so true that our peak temperatures in all cycles would FOLLOW the peak of CO2. It never happens that way tough.
  14. A detailed look at climate sensitivity
    Could anyone explain how it got almost 3C warmer than now prior to the last Ice age with lower CO2 levels?
  15. A detailed look at climate sensitivity
    "A common misconception is that the climate sensitivity and temperature change in response to increasing CO2 differs from the sensitivity to other radiative forcings, such as a change in solar irradiance. This, however, is not the case. The surface temperature change is proportional to the sensitivity and radiative forcing (in W m-2), regardless of the source of the energy imbalance. " The problem with this statement is that it assumes that variation doesn't exist between different sets of climate couplings/forcings-ie the idea that negative feedback can act on one parametre and not another. Eg: lets say we increase sunlight, which for sake of argument, reduces cloud cover in temperate regions, producing a positive feedback. T rises higer than it would from solar output alone. Eg2: lets say we increase c02, which warms the tropics, which, for the sake of argument, produces more low cloud cover (more water held by air in warmer temperatures) which increases endothermic cooling due to more coulds/precipitation (same mechasim as our bodies sweating-which is also probably ocuring now with increased in rainfall in tropics with La Nina). A negative feedback from a rise in C02. In the 2 above examples, one is a strong climate senstivity with regards to the sun, the other a low climate senstivity with regards to c02. Why do the 2 sensitivities have to always be the same?? (sun/c02)? If you argue that the sun would also produce more clouds in teh tropics from the same sort of warming this isnt necassarily so, because the increase in solar output is logarithmic between the tropics and the arctic due to variation in angle of incidence, whereas c02 would be more uniform from tropics to arctic. So not only is there possibly variations in feedbacks between c02/sun, but also variations in feedbacks between various focrings between the tropics and arctic. Even if the above examples are mistaken, I just dont see how all climates sensitivities have to be the same- ie all high climate sensitivity, or all low climate sensitivity. ?? (Moreovoer the 1.2 degrees with C02 regardless of feedback isnt assured either, due to much the same sort of issues).
  16. A detailed look at climate sensitivity
    Question. At what temperature does an Interglacial Period begin in Figure 1 and at what temperature does it end?
  17. A detailed look at climate sensitivity
    The line from RealClimate is the most telling, it amazes me that people can ignore its impact: "... warmer than it has been in millions of years, ... longer than the history of huan agriculture". It amazes me that anyone believes we can cause that great a change so quickly and not expect drastic and unpleasant changes as a consequence.
  18. Climate and chaos
    Wow, HR @10, that's an amazingly biased reading of two very conservative, patient articles explaining weather and climate variability. I'd be thrilled if the people in the news media read and understood those two articles, because if they did, climate reporting would be much more level-headed, even, and accurate. If anyone is interested, NOAA has a nice interactive graphic on how arctic ice retreat can affect winter weather in eastern North America and eastern Asia. It should definitely be linked to in some of this site's responses -- like the "gee, it's cold in X today, where's the global warming?" response.
  19. What do you get when you put a climate scientist and 52 skeptics in a room?
    This is amazing
  20. Climate and chaos
    Science says extreme event will become more common, Trenberth notes that dealing with an extreme event may make the Russians realise that all in not a bed of roses with global warming. What he is not saying is that heat wave was caused by global warming. Only - get used to them because they are going to become more common.
  21. What do you get when you put a climate scientist and 52 skeptics in a room?
    We will have to live with the knowledge that most people (including me) don't have the time, energy or expertise to fully understand the situation. We are, in effect, cheerleaders on the side lines. My belief that the "difficult to convince" brigade are wrong is based less on the science than it is on their tactics. Try to get the "skeptics" to tell you which parts of the AGW argument they agree with, and they won't answer. They want to keep all avenues open, so that if the situation demands it they can argue that we are not responsible for the increased CO2 in the atmosphere, or that the CO2 makes no difference anyway, or that more is good, or whatever. The last thing they want is to agree on everything except (say) the nature and magnitude of feedbacks. Because then, if it turns out they are wrong on feedbacks, they have to accept AGW in its entirety. This actually provides a way of separating genuine skeptics from denialists. The genuine skeptic will tell you where their understanding differs from the climate scientists. The denialists won't. So to me it looks like Roy Spencer is ok. Because he is very firm on what he does believe.
  22. Climate and chaos
    Sorry, where in the NASA GISS piece does it say that the extreme events were caused by global warming? Record temperatures and extreme event are CONSISTENT with global warming but its drawing a long bow to suggest that this is propaganda not facts. I don't think the NOAA article is clear that events have nothing to do with climate change. Its pointing out that cold spells aren't inconsistent with climate change. However, I don't think we actually know a warming planet will affect the patterns responsible for those weather events yet. Papers to contrary welcome. It seems hardly surprising to me that you get more precipitation in places in a warmer world, and that if temperatures drop below zero, then it will fall as snow.
  23. Climate and chaos
    Or what about these quotes from Kevin Trenberth in a Reuters article. This is science from the scientists via the media. Don't forget the fear mongering 'War on Terror' quote from the senior scientist at the end of the piece. All good science!
  24. What do you get when you put a climate scientist and 52 skeptics in a room?
    John... You're right. That was the other thing I really took away from the piece. I couldn't help feeling like most of what Stephen was saying was going right over the heads of most of the audience. How many of those people understood what a bell curve is? Even the guy who was a doctor couldn't grasp the idea that we are accumulating CO2 over time. Or, the guy who just couldn't seem to get over the fact that 380 ppm is such a tiny number. Even the informed ones really had a long way to go to really understand what Stephen was actually saying. Scientists have to lower their sights while not sounding like they are talking down to people. That's a really tough job. Whereas it's profoundly easy for a Lord Monckton to trumpet misinformation and make people feel as though they're somehow a little smarter. I did learn something I didn't know before as well. The uncertainties regarding clouds were new to me. I've heard this information in passing before but not read or heard anything. I thought Stephen did a really good job of explaining it. This should be an ongoing series. And longer shows. People want to understand this better. Even the skeptics. I'd be all for roping each IPCC contributing author into doing a minimum of two hours of shows exactly like this.
  25. Climate and chaos
    "I suggest you get your science from scientists. " scaddenp most people don't get their science from scientists but filtered through the news. If a scientist or science institute put out a press release suggesting the Moscow and Pakistan events are tasters of whats to come from climate change it's impossible not to think that the two things are not going to become linked. In this article NOAA have been very clear in their explanation that the recent winter snows in the US are related to two weather events coming together in a rare conjugation and equally clear that these events have nothing to do with climate change. NASA GISS discuss Moscows summer events under the headline "What Global Warming Looks Like". It's actually possible to be equally clear about the Pakistan and Moscow events being linked to very specific weather conditions. These were driven by changes in the jet stream. Leading to heavy monsoon rains falling in the mountainous catchments of Pakistans rivers rather than lower down on the plains. This paved the way for the terrible flood surges. The jet stream shift also allowed hotter weather to move north over Moscow. It's very easy to be as clear that these events are unrelated to climate change but NASA GISS choose not to do this. I see why NOAA are so clear about the cold winter, some were using it to suggest the end of global warming. Without resorting to bias and underhand tactics I can't explain why NASA GISS can't be equally clear about this summers events. This scaddenp is propapanda dressed up as science.
  26. What do you get when you put a climate scientist and 52 skeptics in a room?
    I found the whole process fascinating and most interesting was the range of reactions. Even in my own household, Schneider would give an answer and I would comment "good answer" and my wife would say "what? I didn't understand what he was talking about at all". Then she would proceed to explain how she would've answered it (and I have to say in the case of the question of ocean pH, her answer was actually better IMHO).
  27. Climate and chaos
    thingadonta, your comment probably will be deleted because of its assertion of researchers intentionally biasing their results in the direction they want. You could just as well have written your comment without that attribution of ill intent. But to your complaint that items other than the starting points are not varied: Please notice that this particular post is about chaos. The key aspect of chaos is that minor changes in the starting conditions cause big changes in the local/near-term trajectory of the system. That is why changes in starting conditions are mentioned in this post. Other aspects of climate models are not relevant to this particular topic of chaos. Please stay on topic.
  28. Climate and chaos
    "This is, incidentally, a technique used by mathematicians to study the Lorenz functions." Mathematicians were the ones who invented collatorised debt obligations, which is a fancy way of saying 'passing the buck whilst at the same time generating fees'. "Models often run a simulation multiple times with different starting conditions, and the ensemble of results are examined for common properties". Strange that they you don't mention the key issue, that the value of the components of the simulations (not starting points) aren't varied because that would produce an outcome not suited to the researcher. You only mention the starting conditions can be changed/variable. So you are willing to assume initial conditions can vary, but none of the model factors/conditions/inputs vary over time, or could be wrong, or the values themselves could themselves be subject to initial conditions. Very telling.
  29. Ocean cooling: skeptic arguments drowned by data
    All I know is the comparative heat map of the oceans displayed on www.globalboiling.com at Seatemps clearly show much hotter sea surface temperature readings every night from the nightly satellite than even the year of Katrina which had been the hottest readings. (except when a hurricane has recently cut a path through the heat and taken some away) and today's radar measurement of the north pole ice shows far less ice than even the least ice ever measured previously right here at nightly radar measurement of polar ice Those are nightly current satellite measurements and are not "subject to interpretation". They are there for everyone to see each day.
  30. Ocean cooling: skeptic arguments drowned by data
    Note to Pielke Snr. Please read Lyman et al. (2010) and Trenberth's article in the same issue. Also, like temperature, surely you must know that in climate science one is interested in long-term trends, and not cherry-picked short-term trends. Global temperatures have not increased much since 2004, so what? The long term (and statistically) significant trend in global SATs and OHC are both up. So you referring to changes over short windows as with OHC (and global sea levels) IS misleading and misinformation, so please do not throw stones in glass houses. Also, why are no comments allowed on your blog? This does not facilitate constructive dialogue. Note to John Cook and GPWayne: He won't admit it, but Pielek Snr's language and commentary on AGW routinely come across as being those of someone who is a "skeptic". That said, I do not think it accurate to conflate/associate Pielke Snr's comments with misinformation tactics used by those in denial of AGW. Perhaps some rewording is required to reflect his actual position. We want to get the facts correct, right? Anyhow, hopefully this can be solved amicably.
  31. Climate change: Water vapor makes for a wet argument
    Johnd- on more try. The surface process. Surface is heated by solar (168) and atmosphere (324). As a result of the heating, it losses some energy to convection (24) and evaporation (78). For the energy to balance however, the surface temperature must rise till it radiates the balance of the energy (390). Note that surface radiation is inputs minus non-radiative losses. It is DEPENDENT on the other processes. The amount of energy that can be lost due to convection and evaporation are physically limited so radiation must do what they cannot.
  32. Climate and chaos
    Dan Olner (#4), Tamino has tried this: http://tamino.wordpress.com/2010/08/12/red-hot/
  33. Climate and chaos
    TOP - "everybody"??? The science position is that warming results in more energy and more water in the atmosphere so extreme events will become more common. This is a statement about trends not events. I suggest you get your science from scientists.
  34. Climate change: Water vapor makes for a wet argument
    johnd - "-390 plus 324 = -66 " WHY are you only using two numbers and concluding there is a deficit? Why do you think you can do maths on only those two? If we can get to bottom of your thinking on that we might finally make some sense.
  35. What do you get when you put a climate scientist and 52 skeptics in a room?
    I agree with what Tony O (#5) said. I'm in awe with the patience that Dr Schneider showed in the face of those long lasted but often equally long debunked sceptic arguments. He mostly kept his calm and reasoning although sometimes I thought to could see irritation flicker over his face and body language. The knowledge he showed and translated to the level his audience could understand...he did it even without the SkepticalScience iPhone app! :p Robhon (#17), indeed there were moments I thought: "Oh, don't say it like that!" and you'd hear the audience disagree instantly. That's where he could do better, but he adapted quickly.
  36. Plain english rebuttal to 'Global warming isn't happening' argument
    Re: ResqDogz (13) A short version of the CO2 is caused by us thread: Due to its isotopic signature, the 40% extra CO2 above background interglacial levels is due to us. WE are the problem. The Yooper
  37. Plain english rebuttal to 'Global warming isn't happening' argument
    Wonderfully simplistic explanation.. but the problem remains: How to convince those obstinate skeptics that mankind CONTRIBUTES to - and exacerbates - global warming? I'm way past tired of hearing "oh, it's naturally cyclical (warming) - and we [mankind] have but a miniscule contribution.. if at all".... What simplistic retort might you have for THEM (other than my first urge to string a few expletives together... you know - something they're SURE to comprehend!)???
    Response: The question of mankind contributing to global warming is indeed the main subject of this website. We have a basic version that looks briefly at 10 human fingerprints on climate change. There's a more in-depth version that takes you through the logical progression of evidence for human caused global warming. Then if you're a glutton for punishment, there's the 'Advanced version' that looks in detail at a number of human fingerprints on climate change.
  38. Human CO2 is a tiny % of CO2 emissions
    Re: John Ballam (58) Mostly. Consider, though, that we now have CO2 levels approximately 40% higher than "normal" interglacial highs... Something to chew on. The Yooper
  39. Human CO2 is a tiny % of CO2 emissions
    Thank you for those answers. So, it's the RATE of addition of CO2 that is the problem. A 3% increase over thousands of years would be largely taken up by the various sinks and could indeed be called "tiny", but 3% in a few decades is unprecedented and too much for the system to bear. Getting there?
  40. What do you get when you put a climate scientist and 52 skeptics in a room?
    Great Stephen Schneider!
  41. What do you get when you put a climate scientist and 52 skeptics in a room?
    Really, a brilliant format for a discussion. It was really good. The deniers in the audience were very on top of the issues they have with climate change. You could tell a lot from the moments where you could hear the whole audience groan at something Stephen said. Climate scientists should take note of those moments and formulate clear answers for those. I hope that some other climate scientists take up this example that Stephen set. I'd love to see Richard Alley do a similar program. I'm sure there are some other climate scientists out there who are also good communicators who could do the same. Trenberth should be up there.
  42. Human CO2 is a tiny % of CO2 emissions
    John Ballam, I second Tom Dayton's remark that this is a good question. Something to keep in mind is that if natural sources and sinks weren't approximately in balance, Earth would quickly become inhospitable for life as we know it. Thus, the fact that our species and our civilization exist (and we are able to ask questions about these things) necessarily implies that we must live on a planet where natural sinks and sources are more or less balanced. Over the long term, however, sources and sinks do fluctuate slowly, as Tom Dayton points out. Thus, there are time periods when CO2 is higher or lower. Note, e.g., the Pleistocene glacial/interglacial cycle, when CO2 naturally fluctuated by around 100 ppm: Figure 1: CO2 concentration over the past 800,000 years from ice cores at Dome C, Vostok, Taylor Dome, and Law Dome. However, as seen on the far right side of that figure, we're currently raising CO2 much more rapidly, and to much higher levels, than anything seen during those glacial/interglacial cycles.
  43. Human CO2 is a tiny % of CO2 emissions
    Good question, John Ballam. Your last paragraph is part of the answer. But since humans continue to add CO2, that new future equilibrium point keeps moving. The other, more subtle, part of the answer is that there is no one special equilibrium temperature for the Earth. The temperature and climate stability of the last few thousand years has allowed human civilization to flourish, but in previous eras the climate was quite different due to different degrees of the various forcings and feedbacks. Except for sudden events such as meteor and comet impacts, changes in the past mostly have been gradual in terms of human lifetime and even human civilizations. So the climate never really reaches an equilibrium, because some forcing or feedback always is changing. But for humans' practical purposes, slow changes are close enough to equilibrium for coping. The human release of massive amounts of CO2 is so fast that the resulting climate changes will be too fast that coping will be tremendously difficult, expensive, and painful.
  44. What do you get when you put a climate scientist and 52 skeptics in a room?
    Yes, Schneider had a wonderful balance of immense knowledge, oratory skills and PR skills. He will be sorely missed. IMHO, this is what more climate scientists need to start doing-- outreach and public education are key. I hope this program gets aired widely.
  45. Human CO2 is a tiny % of CO2 emissions
    Can you answer what I think is a more sophisticated version of the “too small to matter” argument? It is often said that natural sources and sinks are in balance, but human emissions throw this balance out and positive feedback sets in. This is in danger of sounding like Gaia-based woo woo. My question is this; why is there a balance in the first place? In other words, why is the equilibrium stable without human activity but unstable with human activity? And in writing that, I think I might have figured out the answer to my own question, though I have never seen this written down. Is it that for *any* CO2 concentration, there is an equilibrium temperature, which the Earth will reach eventually. Human emissions have shifted that equilibrium position higher. We wiould eventually get to a stable point at current CO2 levels, but it will be much higher than today’s temperature. Is that it? John
  46. What do you get when you put a climate scientist and 52 skeptics in a room?
    I also learned a lot from this discussion, one of them being that "denialists" are mostly confused people who had fastened onto convincing but poor arguments that Schneider was able to refute. Schneider is a great loss. Possibly only someone of his stature and breadth of knowledge could deal with so many arguments in the same session. We don't have many of his calibre to replace him.
  47. Ocean cooling: skeptic arguments drowned by data
    Obviously, there is a lot less ice than there used to be (on both land & sea) and the energy used to melt that ice had to come from somewhere. So yes, that would tend to reduce the apparent warming of the ocean and atmosphere. But the magnitude of that latent heat is pretty small, even if PIOMAS were severely underestimating ice melt. Melting all the normal Sept. sea ice in the Arctic (~13400 km3) would take around 6.7 * 10^20 J. For comparison, the units in the graph of "Upper Ocean Heat Content Anomaly" are 10^22 J, two orders of magnitude larger. I made a typing error (though not a calculation error) in my previous comment up-thread. Melting one gigaton of ice is 3.3355 * 10^17 J, not 333.55. The calculations in that comment were done using the correct number; I just wrote the wrong one when transcribing it here. Sorry!
  48. Ocean cooling: skeptic arguments drowned by data
    macwithoutfries, the difference between the PIOMAS and ICESat results on the graph you show is actually fairly small... and if 10,000 km^3 of Arctic sea ice had been lost since 2005 the total would now be negative. :] We should see how well PIOMAS has done when Cryosat II data starts getting released in the next couple of months. BTW, PIOMAS just updated earlier today with results through 8/31. Looks like the anomaly is at about -9,500 km^3. Given that's against a baseline of ~14,000 km^3 that puts the total volume around 4,500 km^3. The previous record minimum (last September) was 5,800 km^3... and we haven't hit the minimum for this year yet.
  49. macwithoutfries at 04:32 AM on 8 September 2010
    Ocean cooling: skeptic arguments drowned by data
    Ned #29 Could it be that (at least since around 2005) the model behind PIOMAS might be way too conservative ? - see ICESat and the end on this graph If the actual volume lost from 2005 to 2010 would be in the range of 10000 km3 things already start looking a little different ...
  50. Climate and chaos
    Dan, that's an interesting comment about determining probabilities for extreme weather events. For instance, the Russian heat wave and wildfires... this is a weather event which has never happened before in recorded history. As I see it that means either it wasn't possible under previous climate conditions or it would have required such a rare combination of factors that it just never happened until now. If it were possible to put numbers to that it'd go a long way towards putting the whole 'no single weather event can be directly attributed to global warming' bit into proper perspective.

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