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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 113251 to 113300:

  1. Visually depicting the disconnect between climate scientists, media and the public
    RealClimate have censored my comments... I have no interest in improving their worthless paper because you can't, it is flawed by design. If I squint at that really hard, I get some clue as to what the problem may be with you having your remarks appear at RealClimate. They're pretty slack but everybody has limits.
  2. Confidence in climate forecasts
    My previous comment lost a little at the end so I repost the last bit. I respectfully suggest that you re-read what I quoted but try doing so a little more slowly and you may see my point about uncertainty more clearly. Of course there is a possibility that you don’t wish to recognise that significant uncertainty exists about global climate processes and drivers. Some people stick to their beliefs no matter what the evidence.
  3. What do you get when you put 100 climate scientists in a room?
    poptech #156 This really is tiresome. As the methodology is systematic it is quite reproducible, although I agree that (as with much social research) they may not have explained every part of the data collection process -a problem relating to space constraints in journals . Anyway, another fixed that for you: "I think I have irrefutably demonstrated ..." Again, it seems that the level of discussion, and your 'legend in his own mind' approach suggests that its really not worth engaging you in discussion.
  4. Confidence in climate forecasts
    Chris, if you don’t find my comment interesting then you don’t have to read them, do you? I wholeheartedly agree with you that “evidence is always preferable to opinion”. If there was convincing evidence I don’t see why von Storch would have considered it necessary to say “I have to admit that I may be wrong with that assessment”. I respectfully suggest that you re-read what I quoted but try doing so a little more slowly and you may see my point about uncertainty more cl
  5. Confidence in climate forecasts
    In my comment #74 I inadvertently said in the penultimate paragraph “Gelman then goes on to say .. ”. This should have been “Roberts then ….”. Sorry if I misled anyone. Doug, ref. comment #76, thanks for that link to a very interesting poll of Americans. The most important point about that poll, as for any, is the original questions. I did consider responding to those questions in the way that I think I would have if I’d been included and leave it to you to place me in the appropriate category but this is not the forum. My guess is that I’d be placed in the “concerned” category. If you want to follow this up then let me know via this one and I’ll start a thread on my Global Political Shenanigans blog. I’m puzzled as to why you, despite your acknowledged lack of expertise in the subject (comment #68), “ .. should be equally amenable to the notion that today's weather in Russia is confirmation of climate change .. .”. I would expect you to be aware that abnormal weather events occurring in parts of the world, such as hot spells in central Russia give no indication of global climate change (the topic of this blog I believe). After all, the Russians were experiencing similar conditions “ .. in 1919, 1920, 1936, 1938 and 1972 .. ” (Note 1) so they’ve seen it all before – that’s weather for you. If you have a particular interest in global weather conditions then you may be interested in looking at the Cola Weather and Climate Data site (Note 2). “As you can see, the temperature outlook for the next two weeks for the areas just north and east of the Black Sea is bad to say the least” (Note 3) . but I do like the official disclaimer. “COLA and IGES make no guarantees about and bear no responsibility or liability concerning the accuracy or timeliness of the images being published on these web pages. .. The underlying data are the direct product of the various operational forecast models run by the National Centers for Environmental Prediction, National Weather Service, NOAA and are supplied without interpretation or correction” – and that’s just about forecasting weather, never mind climate change forecasts (don’t forget that the UK Met Office uses the same model for both). We can all expect the cost of a loaf of bread to rocket as a consequence of this weather event. Of course, Yahoo Green has a different take on this (Note 4). Peter (Hogarth) “envisaging possible future climate” is significantly different to predicting them. NOTES: 1) see http://www.kyivpost.com/news/russia/detail/73341/ 2) see http://wxmaps.org/ 3) see http://www.thepoultrysite.com/poultrynews/20637/cme-russian-heatwave-may-spark-wheat-crisis 4) see http://news.yahoo.com/s/time/20100802/wl_time/08599200808100 Best regards, Pete Ridley
  6. Three new studies illustrate significant risks and complications with geoengineering climate
    LewisC, I come from a country that is known to have the cleanest fresh lakes, soil and air in Europe. Despite this forests was dieing and lakes life was wiped out due to acid rains. Since the 70ties chalk has been dumped in lakes and forest has been spray from the air with chalk powder to combat acid rains and prevent forest and lakes from dying. All this in the cleanest country of Europe – imagine the rest... This and this is what happen. Historical architecture was literally falling apart in front of our very eyes due to acid air pollutions. However, the air in Europe has now been cleaned up to such extent that cupper plated roofs now turn black instead of green, I think I can live with out the greenish cupper plated roofs. We do not need to know more about acid rains than the already known effects to dismiss such an idea as futile.
  7. Waste heat vs greenhouse warming
    Well, that certainly confirms my impressions RSVP. Thanks for the additional insight.
  8. Waste heat vs greenhouse warming
    doug_bostrom 202 If you think I am beating a dead horse, thirteen days (July 27 to Aug 8) is nothing. In 1976, I did a paper in High School about whether the Earth was warming or going into an ice age. (I remember including things about CO2 monitoring in Hawaii, and questions about the Earth's albedo changing, and if I am not mistaken the question of cooling or warming was still open. I had never heard the name Al Gore.)
  9. Visually depicting the disconnect between climate scientists, media and the public
    Poptech, did you notice that Anderegg et al are actually paying attention to the RealClimate thread? Forgetting for a moment that you're apparently the only person carrying the "can't use google scholar torch," why are you over here endlessly repeating yourself when your chance to have your concerns addressed is over at RealClimate? If you're actually concerned about improving things, jump on over to RealClimate and have at it. You've got your golden opportunity, use it. Failing that, readers here are going to be left with only the conclusion that you're trying to create and preserve an impression without bothering to exploit a rare opportunity for dialog, for whatever reason.
  10. It's cooling
    Doug: Thank you for the von Schuckmann paper.
  11. What do you get when you put 100 climate scientists in a room?
    FTFY: I have produced a subjective and fairly poorly thought out attempted rebuttal of the PNAS paper by Andresson. It looks to me that because their methodology was systematic, and designed to generate a sample of data, it's fine. You're demanding a census which is really not possible without a good deal of resources. Anyway, if they were to use ISI web of science, which has less inclusive indexing criteria, this would be unacceptable to you as well, due to poorly thought out reasons that you have inflicted on us previously ;).
  12. 10 Indicators of a Human Fingerprint on Climate Change
    "We," AlanR? Superficially speaking "we" have some hints that you are sufficiently motivated as to register here and ask questions in a way that suggests you are familiar with this topic but at the same time insufficiently curious to make an effort to find answers on your own, a seeming paradox. Or perhaps you are not curious, it's hard to say exactly without more data. Now you appear to be departing from the world of facts, presumably imagining "cooling" or the like in the face of overwhelming evidence to the contrary as well as sliding into the fuzzy world of semantics and rhetoric, which helps to confirm that further discussion of science with you is probably pointless. I could be wrong, of course.
  13. michael sweet at 10:22 AM on 8 August 2010
    Confidence in climate forecasts
    Joohnd at 67: The specific prediction of an El Nino (or La Nina) is weather and not related to long term climate forcasting. The climate modelers do not claim the ability to forcast these reliably. You need to produce an example of a long range climate model in action, not a weather model.
  14. 10 Indicators of a Human Fingerprint on Climate Change
    Why Doug, the warming effects we noted at #47. ACO2 is CO2. I think so too. The IPCC models treat them differently. Easy yes. Mystery no.
  15. Visually depicting the disconnect between climate scientists, media and the public
    For what it's worth, any possibly substantial quibbles with the Anderegg paper are much narrower than what poptech mentions. There's an interesting and informative thread at RealClimate on Anderegg's limitations: Expert Credibility in Climate Change – Responses to Comments on the topic. A fellow going by the handle of "RomanM" appears to bring up the sole possibly serious issue. There's no agreement on whether his point is truly valid, though it would be interesting to see the analysis redone using his suggestions. It's also fairly clear that a redo using RomanM's take won't change the results much. I personally find it really interesting see how vigorously the notion of lack of consensus is defended by contrarians. They've highlighted and even could be said to have synthesized this matter and now when the concept comes under serious attack they're amazingly keen to defend their construction. The time could be better spent doing science on the core issue as opposed to meta-science, but contrarians did insist, after all. Expect more on the topic, creating an entire subdomain of contrarianism as we appear to see emerging even now.
  16. Has Global Warming Stopped?
    #61: "are the temp observations during that period representing a rise in temperature or are they random?" Temperatures can't be random. If its hot now, its more likely to be hot a short while from now. Physical properties of water and air limit instantaneous rates of temperature change. Unless we know the underlying physics, how can we presume to say that any specific power function is any more than a mechanical fit through data points? How do we know quadratic is bad and quartic is good? Without an underlying model, all we can do is be descriptive of what's going on in the data. As an example from a prior post, The linear fit is virtually meaningless, but its the number everybody quotes as 'trend'. I'd be tempted to try an even power (concave up), but even that is meaningless -- as it would keep going up faster and faster forever. Even the most ardent warmist wouldn't make that claim! I've learned to prefer LOESS, an adaptive smoothing process, which produces results that are very similar in appearance to moving averages. If a rate of change is needed, a symmetric difference quotient of the smoothed values works wonders. From this graph, is it not reasonable to conclude that temperatures are rising faster during the last 50 years? And that's a conclusion that might just shed some light on where to look for an explanation.
  17. It's cooling
    Full text of von Schuckman here (pdf).
  18. 10 Indicators of a Human Fingerprint on Climate Change
    Damped the effect, AlanR? What effect are you speaking of? C02 is C02, excepting isotope markers which don't affect P-chem. If you have a system that has been cycling C02 in a rough state of equilibrium and you dump a large additional amount into that system, you'll see a bulge of unprocessed C02, failing the emergence of increased processing power. The IPCC refers to the lack of excess capacity in the existing system. In this case, once enough time has passed we'll see the bulge eventually diminish, ironically in part because of increased temperature in the system. If the system had previously had -excess- capacity we'd have seen a trend of decreasing C02 prior to the C02 glut we've imposed on the system, if the trend were short enough to have allowed us to develop the capacity to make such measurements. Easy enough. The remaining mystery is, was that actually a mystery?
  19. 10 Indicators of a Human Fingerprint on Climate Change
    Yes. Hard to say what has damped the CO2 and vapour effect for the last fifteen years. I'm not sure if ACO2 behaves itself either. Unlike natural CO2, of course. The oceans cheerfully exchange 90 gigatons natural CO2 each year though they appear to miss half the ACO2. IPCC: In current models, the uptake of anthropogenic CO2 is controlled mainly by physical transport and surface carbon chemistry, whereas the natural carbon cycle is controlled by physical,chemical and biological processes.
  20. It's cooling
    Susan Wijffels presentation for OceanObs 2009 had a slide that she credited to Palmer 2007 that compared eight different analyses down to 700 m. They all disagreed but had visibly the same shape, and averaged 0.3 W/m**2 over about 50 years. The von Schuckman 2009 paper obviously took advantage of the Argo network, went down to 2000 m, but estimated power at 0.77W/m**2. Furthermore, the 700m analyses had about four times as much accumulated heat. Either von Schuckman has discovered something new and exciting, or the Argo system still has a few bugs. In either case, the world is going to be full of papers which are going to examine the Argo data in detail, and compare it to predecessor data. It might be a real good idea to let the dust settle before using the data.
  21. Confidence in climate forecasts
    Pete Ridley at 06:59 AM on 8 August, 2010 "Doug (Bostrom) hit the nail right on the head with his "that's my inexpert advice". Most of us here are offering our inexpert opinions and advice for free and there is a saying “Free advice is worth what you pay for it”." Doug is showing a certain amount of humility. In truth Doug is both rather well informed and more importantly (we've learned from our experience here) honest and informative. There are many posters here with strong backgrounds in the physical sciences that can address the scientific evidence with insight and understanding and are able to communicate this. So this site is a very good forum for gaining understanding of the science (if one chooses to be informed of course). Careful not to make the mistake of thinking that any old stuff one posts is of equal value (the pretence that everything might be dragged down to a low "common denominator" can be a conceit for those with deficient arguments!). I expect pretty much everyone that reads these threads is able to recognise honest attempts to present relevant evidence, summarise the science, perhaps to question this, and engage in an informed exchange of ideas....
  22. Waste heat vs greenhouse warming
  23. What do you get when you put 100 climate scientists in a room?
    gallopingcamel, I think that you misunderstood my comment about nuclear power being viable for private transport. I wasn’t referring to electric cars, which do have a use, for example as you say for commuting. I see their drawback being their expensive batteries (life-cycle costing) and low energy capacity compared with petrol/diesel engines. Few of us even in the developed economies can afford to have one car for commuting or short distance journeys and another for long-distance. The millions of aspiring car owners in developing economies, e.g. in Asia, have their eyes on one low-cost vehicle suitable for carrying a large family long distances. Perhaps the hybrid is the answer. As for Barry Brook leading us anywhere – not for me thanks. Best regards, Pete Ridley.
  24. Peter Hogarth at 07:34 AM on 8 August 2010
    Confidence in climate forecasts
    Pete Ridley at 06:59 AM on 8 August, 2010 It is indeed interesting to re-read von Storch. JMurphy and Chris have already highlighted some pertinent quotes from this article elsewhere, but here's another which may give you pause for thought on your comments on climate modeling: “in popular debates sometimes the argument is voiced that since it is impossible to predict the weather of the next season it would be impossible to assess changes in a few years or even decades of years. All attempts to predict climate would therefore be doomed. However, these attempts are not doomed, –contemporary climate models are indeed capable of envisaging possible future climate”. Of course there are caveats, models give us possible scenarios, worst case/best case. Von Storch does not seem optimistic about our ability to achieve best case.
  25. Confidence in climate forecasts
    Pete Ridley at 06:59 AM on 8 August, 2010 Since the evidence for skill of climate models is an extant fact (see e.g. Doug's post above and the link to Julia Hargreaves article), one isn't impressed by poorly-informed assertion ("The climate models are structured from scientific hypotheses that are based upon dubious statistical manipulations, unsound...."). A useful approach to science involves a rational and honest consideration of the evidence. Your he said this...he said that construction to support your opinion isn't very interesting. You select one element from von Storch's article that you like but dismiss the fact that von Storch presents strong arguments for the nature of anthropogenic global warming, and expresses concerns about future consequences (he obviously doesn't consider anthropogenic global warming a "hypothesis"). We're left wonder at what point your apparent reliance on expert sources starts and finishes...in the end it seems like you make dainty selctions based on your opinion! evidence is always preferable to opinion Pete!
  26. Waste heat vs greenhouse warming
    KR 200 "You put 0.028 W/m^2 out via AHF. Perhaps it takes a while to get into the environment" A cars engine "warms up" around 90 C. With the car not moving, the air temperature around the radiator begins to approach this same temperature, and it gets there in no time. With the car moving, air cooling the engine does not get so hot, but instead there is more air affected. In either case, the point is the atmosphere takes up this energy instantaneously. Then problem after that is how long it takes to leave the environment. AGW is based on the idea that non GHG have almost zero emissivity. Divide CO2 emissivity by nearly zero and multiply by .028 and you get global warming for real. "Nah, not an issue" ????????????
  27. Confidence in climate forecasts
    By the way, that's a interesting continuum from expertise to dilettante you cite there, Peter. I thought you were keen to rely on experts but here we rattle to a conclusion based on purloined emails and something that turned out to be a fake, synthetic scandal? Hardly a strong scientific case for exaggerating uncertainty, all in all.
  28. Confidence in climate forecasts
    See this as an example, Peter, w/methods properly explained. There's a pretty large gulf between simple opinion polling and carefully constructed elicitation. I'd suggest if you see a trend in skepticism, you should be equally amenable to the notion that today's weather in Russia is confirmation of climate change. :-)
  29. 10 Indicators of a Human Fingerprint on Climate Change
    Well, so far clouds don't seem to be doing the job for us. I hope water vapor makes up its mind soon whether or not to condense and where, heh! Thinking on clouds seems to have converged on the notion that altitude counts for a lot, w/high altitude clouds being a net positive forcing agent versus low altitude clouds, and that longwave vs. shortwave cloud forcing works in opposition, w/net effects sometimes canceling and sometimes not. Optical depth is important. Here are a few papers on the topic: The Influence of the 1998 El Niño upon Cloud-Radiative Forcing over the Pacific Warm Pool Cloud Radiative Forcing of the Arctic Surface: The Influence of Cloud Properties, Surface Albedo, and Solar Zenith Angle Altitude dependence of surface radiation fluxes and cloud forcing in the alps: results from the alpine surface radiation budget network Sea Surface Temperature and Large-Scale Circulation Influences on Tropical Greenhouse Effect and Cloud Radiative Forcing Interestingly, altitude effects are sufficient that aircraft contrails become an matter for examination w/regard to minimizing their formation: The impact of cruise altitude on contrails and related radiative forcing
  30. Confidence in climate forecasts
    Argus, in my inexpert opinion the reason that the media prefers scare stories to reality is that it attracts more of the available audience, hence more funding for the most scary media release. I also opine that the politicians and others who promote the most scary projections of those models do so not out of concern for global climate change but for other vested interests but this is not the forum for such debate. You may be interested in taking a look at my “Global political Shenanigans” blog (http://globalpoliticalshenanigans.blogspot.com/). Doug, I’d be interested to know which “ .. scientifically conducted research into public opinion .. ” you are depending upon to support your view that Argus’s perceptions put him “ .. in a small minority of persons .. ”. The public opinion polls that I have seen recently show a clear trend toward scepticism among the general public about The Hypothesis. Best regards, Pete Ridley
  31. Confidence in climate forecasts
    Doug (Bostrom) hit the nail right on the head with his "that's my inexpert advice". Most of us here are offering our inexpert opinions and advice for free and there is a saying “Free advice is worth what you pay for it”. The climate models are structured from scientific hypotheses that are based upon dubious statistical manipulations, unsound assumptions and estimates used as a poor substitutes for a proper understanding about global climate processes and drivers. Rather than paying much attention to inexpert opinions I prefer to listen to the advice of those with some expertise in the subject, such as Professor Hans von Storch, of the University of Hamburg’s Meteorological Institute. Although he is a supporter of The (significant human-made global climate change) Hypothesis, he is honest about the scientific uncertainty upon which it is based. In his 2009 paper “On Adaptation – a secondary concern?” (Note 1) von Storch says such thing as:- “.. How fast can climate change when only natural causes are operating? This rate may be described by a probability distribution .. (which) .. must be estimated from the limited evidence provided by the observational data base of the past 150 years and by indirect “proxy data”. It is not possible to prove that the estimation is “right”; we can only show that it is consistent with the little knowledge we have. I personally believe that our estimates are approximately correct – but I have to admit that I may be wrong with that assessment”. “Commonly accepted knowledge is that no more than one third of the warming of the past hundred years can be explained by increased solar output; the remaining two thirds can be explained only by the effect of elevated greenhouse gas concentrations, i.e., the anthropogenic greenhouse effect. There is a caveat, .. the quality of estimating the magnitude of naturally caused variability is a key issue in this exercise. This magnitude is not known but must be estimated. Accepting its estimated value is a matter of trust. If somebody believes that the estimate is inadequate because of the limited data base, then I can not disprove this assertion. The same is true for my belief that the data base is good enough to allow a reasonable educated guess of this quantity – possible opponents are not able to prove that I am wrong. This controversy has nothing to do with incapable scientists but with the fact that the data available to us are limited. The problem can be solved only by either waiting for a long period of extra time .. or by accepting claims such as realism of contemporary climate models”. I shouldn’t need to explain the significance of those comments but for any who need a hint, look for words like “limited evidence”, “belief”, “may be wrong”, Contributors here may find his blog Die Klimazwiebel (Note 2) enlightening but it will only help those with an open mind. I wonder who will be the first one here to cast doubts about Professor Storch’s pedigree. Andrew Gelman, Professor of Statistics and Political Science and Director of the Applied Statistics Center at Columbia University, uses that “Free advice .. ” as the title of one of his threads. Following up on this led me to an associate of his, Seth Roberts, professor emeritus of psychology at UC Berkeley. In his article “Physicists Disagree about Climate Change” (Note 3) he quotes opposing opinions on The Hypothesis from two physicist friends. Gelman then goes on to say “At risk of sounding v smug, my views have changed only a little. I already thought the consensus was more fragile than it appeared. That’s just a general truth about modern science. I was already skeptical of climate models because I knew how easily modellers fool themselves. I began to believe the consensus was not just fragile but wrong when I heard the story of the Yamal tree ring data — the long refusal to supply the raw data and, when the researcher’s hand was forced and the data finally supplied, the way it contradicted the claims that had been made. Climategate didn’t vastly change what I thought; it provided more evidence for ideas I already had .. ”. I love that bit about modellers fooling themselves. – enjoy. NOTES: 1) see http://coast.gkss.de/staff/storch/pdf/BadHonnef_0805-adaptation.pdf 2) see http://klimazwiebel.blogspot.com/2010/08/sustainable-science.html 3) see http://www.wellsphere.com/general-medicine-article/physicists-disagree-about-climate-change/909357 Best regards, Pete Ridley
  32. Confidence in climate forecasts
    johnd wrote : "Personally I believe the experimental coupled GCM from SINTEX JMA of Japan is the most accurate, more so then the combined results of the ensembles. About 3 years ago it went completely against ALL other models that were predicting an imminent and large La-Nina and was the only one to have gotten it right." johnd, the link you provided was for June 2010, showing the SINTEX JMA agreeing with most of the other models. Do you have a link to the result three years ago, which you were so impressed by ?
  33. Why I care about climate change
    Pete Ridley at 05:54 AM on 8 August, 2010 Your propagandist approach to this isn't that interesting ("The Hypothesis" indeed!), and it might help you to take a more balanced approach if you would read the von Storch article you recommend. von Storch certainly doesn't consider "significant human-made global climate change" a "hypothesis", and no one who is in any way informed on this subject would do so (climate scientist, scientist, or otherwise informed individual): here's von Storch quoting from page 10 and 11 of the document you provide a link to:
    "…anthropogenic climate change is ongoing now; it can not be stopped; all what we can do is to limit climate change. The foreseeable future will hardly see any reduction of global emissions – but merely reductions of global emission growth.5 If we continue with business-as-usual and if no deus-ex-machina technological fit surprisingly emerges, we may well end up with a tripling or maybe even quadrupling of greenhouse gas concentrations in the atmosphere at the end of the current century. Such levels will have severe implications. Making serious attempts to reduce emissions, we may be able to limit the increase in the greenhouse gas concentrations to a doubling of pre-industrial levels.6 “Doubling” is to be considered an achievement; a successful limitation. But also a doubling will have serious implications. Therefore we have to consider adaptation to climate change, not instead of, but parallel to mitigation of climate change. The goal is to limit the accumulation of greenhouse gases to “only” a doubling (or any other achievable significant reduction) and to prepare societies and ecosystems to adapt to unavoidable future changes."
    We have to be rather more rational about the realities of mitigation and adaption. There's no question that we will take steps to mitigate the problem (as von Storch says) and of course there's no question that we will be forced to take adaption responses to the effects that will develop from anthropogenic global warming throughout the current century (and beyond no doubt) which we will be unable to mitigate against. Mitigation is always preferable since it allows us to take a degree of control of future events and will minimize the possibilities of the potentially dramatic consequences that lie on the "nasty" side of the uncertainties inherent in any projection that is only bounded by ranges of probabilities.
  34. Why I care about climate change
    Pete Ridley wrote : "I anticipate many global benefits from a few degrees of global warming and regard the warnings of climate catastrophe as a consequence of our use of fossil fuels to be nothing more than propaganda from political and environmental organisations like the UN, Greenpeace and WWF." Can you list those 'global benefits' and give the scientific backing for them ? Could you also show the evidence that reveals that 'propaganda' ? Pete Ridley also wrote : "John says of his acceptance of The (significant hiuman-made global climate change) Hypothesis that he “ .. wouldn't characterise it as 'belief', this is not a matter of faith ..” but he is no more an expert in this subject than you or I or any others subscribing to his blog. It is worthwhile looking at what Professor Hans von Storch, of the University of Hamburg’s Meteorological Institute, a scientist with real expertise in the subject has to say about it (Note 1)." From your link : In order to avoid misunderstanding, I am declaring already now: I am convinced that humankind can change climate, and I am equally convinced that humankind is presently changing climate. So, von Storch agrees with John's acceptance of AGW. I still find it very odd the way you write about AGW as "The (significant hiuman-made global climate change) Hypothesis" but think you will find that you are the only one who believes in such a strange, convoluted term which obviously helps you to accept whatever beliefs you have made up for yourself about climate and man's influence on it.
  35. Confidence in climate forecasts
    Another retrospective of Hansen's model of 22 years ago, and some expert remarks on the utility of models in general: Skill and uncertainty in climate models From the abstract of the paper analyzing Hansen's model: Analyses of skill are widely used for assessing weather predictions, but the time scale and lack of validation data mean that it is not generally possible to investigate the predictive skill of today's climate models on the multidecadal time scale. The predictions made with early climate models can, however, be analyzed, and here we show that one such forecast did have skill. It seems reasonable to expect that predictions based on today's more advanced models will be at least as skillful. In general, assessments of predictions based on today's climate models should use Bayesian methods, in which the inevitable subjective decisions are made explicit. For the AR4, the Intergovernmental Panel on Climate Change (IPCC) recommended the Bayesian paradigm for making estimates of uncertainty and probabilistic statements, and here we analyze the way in which uncertainty was actually addressed in the report. Analysis of the ensemble of general circulation models (GCMs) used in the last IPCC report suggests there is little evidence to support the popular notion that the multimodel ensemble is underdispersive, which would imply that the spread of the ensemble may be a reasonable starting point for estimating uncertainty. It is important that the field of uncertainty estimation is developed in order that the best use is made of current scientific knowledge in making predictions of future climate. At the same time, it is only by better understanding the processes and inclusion of these processes in the models, the best estimates of future climate will be closer to the truth. Here's how Hansen's model looks in retrospective tested against the null hypothesis: Forecast of Hansen et al.2 (blue line) evaluated against observational data (black). Twenty-year trends of forecast and observations are indicated with thick lines, as is the null hypothesis of zero trend (red). So we see that 22 years ago it was possible to construct a model that would predict behavior of the the Earth climate system w/some fidelity, no need for backwards-looking tweaking or the like. 12 years later, from 2000, we have another sample including more model runs to look at: From Intercomparison of Present and Future Climates Simulated by Coupled Ocean-Atmosphere GCMs As Hargreaves remarks, it's hard to imagine models are becoming worse over time. It's also possible to see that so-called "wide variances" between different models and different model instantiations don't have much to tell us about the fundamental utility of models because while such variances do indeed emerge decades into various model runs those models still tell us the same basic story, the planet will continue warming up. "Just models," of course, but observational evidence seems to largely coincide w/model output as we can see from Hansen's very early example. Quibble over wiggles, we can still do that of course.
  36. 10 Indicators of a Human Fingerprint on Climate Change
    Doug I think you are right. It would be good to see the cloud issue settled before high confidence is declared. IPCC. Clouds, which cover about 60% of the Earth’s surface, are responsible for up to two-thirds of the planetary albedo, which is about 30%. An albedo decrease of only 1%, bringing the Earth’s albedo from 30% to 29%, would cause an increase in the black-body radiative equilibrium temperature of about 1°C, a highly significant value, roughly equivalent to the direct radiative effect of a doubling of the atmospheric CO2 concentration
  37. Why I care about climate change
    Gallopingcamel, I mainly agree with your comments (#111) but suggest that mitigation is not about controlling global climate changes but about living with the impacts of them, wherever it might occur and whatever might be the cause. This is something that humans have done since the beginning. I anticipate many global benefits from a few degrees of global warming and regard the warnings of climate catastrophe as a consequence of our use of fossil fuels to be nothing more than propaganda from political and environmental organisations like the UN, Greenpeace and WWF. John says of his acceptance of The (significant hiuman-made global climate change) Hypothesis that he “ .. wouldn't characterise it as 'belief', this is not a matter of faith ..” but he is no more an expert in this subject than you or I or any others subscribing to his blog. It is worthwhile looking at what Professor Hans von Storch, of the University of Hamburg’s Meteorological Institute, a scientist with real expertise in the subject has to say about it (Note 1). Please see my comment today on the “Confidence in climate forecasts” thread. I do not believe that the Asian countries mentioned support The Hypothesis. It seems to me that their efforts on reducing the emissions of pollutants from their coal-fired electricity generation stations (is that one a month or one a week that the Chinese are installing?) is nothing to do with reducing emissions of that essential life-supporting substance CO2. The objective is to reduce to acceptable levels the real pollutants listed by The Union of Concerned Scientists (Note 2). These are (annual figure for a typical power station) - particles (500 tons), CO (700 tons), SO2 (10k tons), NOx (10k tons), VOCs (200 tons), Hg (170 pounds), As (200 pounds), Pb (10 pouinds), Cd, etc. Excluding the CO2 that the UCS includes in its list, the rest do need to (and can) be reduced to reasonable levels using the latest “clean coal” technology, as the Chinese are doing. Interest in the development of alternatives, including renewables, is for economic reasons, not as a means of global climate control. NOTES: 1) see http://coast.gkss.de/staff/storch/pdf/BadHonnef_0805-adaptation.pdf 2) see http://www.ucsusa.org/clean_energy/coalvswind/c02c.html Best regards, Pete Ridley
  38. michael sweet at 05:20 AM on 8 August 2010
    Grappling With Change: London and the River Thames
    Doug, Your link at 16 was an interesting read. Unfortunately it seems that the real pain will not be for several decades. If that is the case and people wait for their thousand cuts to start before taking action it may be a late start. While this was more up to date than the Tampa plan, they still estimate only a maximum of 0.65 meters by 2080. IPCC estimates for the next report will likely be up to 2 meters by 2100, more than double 0.65 m by 2080. GC, I have not seen the Dutch dunes, although I believe you that they are impressive. I do not think that Florida can copy them. The area to be protected is too big. Are you going to build the levies on our tourist beaches? Even if you were able to protect the cities, how would you protect the roads and get fresh water to drink? Holland has water run in from higher land while Florida gets salt intrusion now. There are only 6 or 8 million people threatened in Florida, we can all move to South Dakota.
  39. Confidence in climate forecasts
    Argus at 02:58 AM on 7 August, 2010 ”So you really believe that a climate model is just a "working replica of the earth" - only it is made from "mathematical equations" instead of "rock and water and other materials"?... No, of course not. A climate model is designed to simulate energy flows within the climate system. It doesn’t have to simulate “rock and water and other materials”. On the other hand a model could include rock weathering by parameterizing a huge amount of physics and chemistry on silicate weathering, and the relevant properties of water (ocean thermocline; mixing between ocean layers and other aspects of ocean heat transport; ocean surface evaporation; latent heat transfer and so on) can all be parameterized according to empirical physics. ”In the post How reliable are climate models? a big deal is made out of the fact that the models "successfully reproduce the past". Of course they do. That is what they were made to do. But predicting the future is another matter.” There is an element of the Monty Python “what did the Romans ever do for us” about your complaint! “Wot ‘ave models ever predicted...... except (i) the moistening of the troposphere at a time when at least one prominent “skeptic” was asserting that the upper troposphere would dry in a warming world; (ii) tropospheric warming during a long period when erroneous tropospheric measures were indicating the opposite (models predicted correctly again); (iii) northern polar amplification of global warming including a significantly delayed Antarctic response (model predictions from the 1980’s); the extent of warming in response to enhanced greenhouse forcing (models from the 1890’s; from 1975 and Hansen’s projection from the 1980’s discussed earlier); that tropospheric warming would be accompanied by stratospheric cooling and the increased altitude of the tropopause (models from 1980s); enhanced nighttime warming over daytime warming and enhanced winter warming over summer warming (Arrhenius predicted this in the 1890’s!); etc. etc. …..apart from that wot ‘ave models ever predicted!” The reason that models have been rather successful in predicting the Earth response to enhanced greenhouse forcing is that the issue is largely one of addressing the amount and distribution of energy in the climate system. There is a massive amount of well-characterized physics with which to parameterize models (the blackbody Earth temperature, the Earth’s albedo, the origin and magnitude of the greenhouse effect, and the fact that the earth temperature response linearly to logarithmic changes in [CO2] were already known and understood in the 19th century). And as I’ve said before there is a wealth of empirical and theoretical data that informs us that the Earth responds with a surface warming between 2 and 4.5 oC per doubling of [CO2]. In effect this can be considered a highly predictive (all else being equal!) model for projecting future temperatures in response to various CO2 emission scenarios. Global circulation models might be considered to be continuous embellishments of this basic energy relationship. They don’t actually have to be that complicated! It’s not obvious that they actually give us much more info about global warming per se than can be gleaned from the climate sensitivity, but of course (as I’ve said before too!) they allow testing of future projections and a focus on differences between model predictions and real world measurements [which so far have largely been settled in favour of the models (see my Monty Python sketch just above)]. ”I imagine it would be almost as hard as making a model of how the human race will evolve during the next million years.” (referring to how hard it might be to make an accurate climate model of the Earth). I wouldn't say so Argus. Physical models parameterized with well-characterized physics can do a good job of simulating relevant elements of physical systems. Since evolution is fundamentally based on stochastic variability (random mutations in heritable DNA), coupled with interactions at the somatic scale (e.g. mate-selection) under the influence of environmental “natural”-selection, buffeted by non-predictable stochastic (car accidents; fatal illnesses; non-reproduction) and contingent events (war, famine, tsunami’s, volcanic eruptions, earthquakes, floods and all the other nasties that can decimate populations unfairly), evolution is inherently non-predictable. ..weather's difficult too...climate not so difficult broadly speaking. n.b. be sure to click on the Monty Python sketch link!
  40. Waste heat vs greenhouse warming
    RSVP - slow distribution vs. fast distribution? Nah, not an issue. You put 0.028 W/m^2 out via AHF. Perhaps it takes a while to get into the environment - a long slow pipe via a river to the ocean and finally heating the atmosphere. Perhaps it goes out quickly - a short pipe directly via convection in a radiator, which only later heats the ocean by conduction/convection. But you have 0.028 W/m^2 going into the 'pipe' - and you have 0.028 W/m^2 coming out of the pipe. You still have 0.028 joules/sec/m^2 added to the environment. The length of the 'pipe' doesn't matter one bit - the rate of energy deposited in the Earth/air/water system does. On your two-barrel analogy - that would have been better put as looking at a single barrel with alternative filters. The 2 barrels really sounded like your previous arguments that there were two different heat stores, which is simply not the case. Keep in mind, though, that it's a very large barrel, and never gets empty, the Earth won't reach absolute zero.
  41. 10 Indicators of a Human Fingerprint on Climate Change
    There are many results indicating statistically significant temperature change, Alan. Global observed changes in daily climate extremes of temperature and precipitation Global Trends of Measured Surface Air Temperature Global rural temperature trends Maximum and Minimum Temperature Trends for the Globe Global temperature change and its uncertainties since 1861 Trends in global temperature Global temperature change Global Warming Trend of Mean Tropospheric Temperature Observed by Satellites Quite a few not mentioned. What's interesting is how old many of these findings are yet a lot of people are not aware of them, even so-called skeptics who ought to be the first to go find out what the facts are. A well-armed skeptic should look at everything before making assertions.
  42. Confidence in climate forecasts
    Thanks, Argus. It's notable that your post w/the remarks about "purpose" was discussing scientific research but as you further describe your feelings it turns out your concerns are about what you see as a tone problem in popular media and what you believe is an agenda pursued by the media to drive political action. That's not an argument about science. Your conclusions about popular opinion are also quite interesting. If you look around for scientifically conducted research into public opinion, you'll find that your perceptions put you in a small minority of persons that while varying by year in proportionality appears to show little if any trend.
  43. Peter Hogarth at 03:38 AM on 8 August 2010
    1934 - hottest year on record
    Broadlands at 01:38 AM on 8 August, 2010 Hopefully looking at the latest USHCN chart and data for US annual temperatures might be helpful and answer some of your questions: It ranks 1934 as 3rd highest temperature after 1998 and 2006. As you know this data set has been analysed by researchers (and critics) over many years, and contains a number of corrections and updates, most significantly (from the point of view of older data), “time of observation” adjustments. The corrections are described quite well for version 1 and most recently for version 2 which is used for the chart. The data, fully corrected, time of observation only corrected, and raw, can be downloaded from here
  44. Confidence in climate forecasts
    doug_bostrom (at 04:32 AM on 7 August, 2010): "What purpose do you believe that to be, Argus?" First, let me say that I am skeptic towards climate models for the same reasons as the signatures Pete Ridley (at 02:23 AM on 7 August, 2010) and johnd (at 11:35 AM on 7 August, 2010), as manifested in their recent comments. They are just expressing themselves far better than I am. "These models make correct predictions because they are based on general scientific principles", Kevin Judd claims about weather modelling programs. Correct predictions - that is quite a statement! And he seems to imply that climate models are just as correct, because "otherwise microwave ovens wouldn't work, aircraft wouldn't fly". He is obviously trying to inject 'confidence in climate forecasts' into the listeners to FM 92.1 (and the readers of this post), by making climate models seem as simple and reliable as "model stream-trains". -- Is it working out? Not for me, but according to doug_bostrom this is only because I am "harboring some misunderstandings about models". As for the question about purpose, I will first give a few examples. Whenever the future of our climate is presented in media, there is too often a tendency to exaggerate: '... warned the world that non-linearities in the ocean-atmosphere system could lead to a whopping 5 meter or more sea level rise over this century' - 'a 5 degree to 8 degree rise in global temperature in the next 100 years, expected by many scientists …' - '… the likelihood of [the glaciers in the Himalaya] disappearing by the year 2035 and perhaps sooner is very high'. I think the purpose behind the use of exaggerated news, is to wake up the masses, alert them so that they will start living more ecologically, and possibly influence their politicians to act sooner (and more forcibly). The alarming predictions are usually based on well chosen climate models, so I think they are influenced by the same purpose. A model that over-predicts global temperatures a bit, or shows a steeper curve, is more useful in this context. Unfortunately, alarming figures and exaggerated predictions do not work well anymore, I think. The public is becoming more skeptic for each new alarming report. I doubt that the purpose of informing the people (which is a good purpose) is served best in this way. New proselytes could possibly be won over more effectively with other methods than serving them half-truths.
  45. 10 Indicators of a Human Fingerprint on Climate Change
    So CO2 continues to rise and water vapour rises to magnify the warming. Unless there's a cloud on the horizon, it can't be long before temperatures rise to statistically significant levels.
  46. gallopingcamel at 01:56 AM on 8 August 2010
    Why I care about climate change
    kdkd (#112) I was not advocating an approach to energy policy as this web site is not into "solutions". My intent was to point out how difficult it is to change energy policies in the countries that are having the greatest impact on carbon emissions.
  47. 1934 - hottest year on record
    DOUG... "Given long enough these changes will work their way up through decimal places and emerge. That's exactly what we see in the global record, variability gradually moving upward."
 But, IS that what we are really seeing, long-term... at least since ~1880? Before 1975 the highest northern hemisphere temperatures occurred in the late 30s, around 1938. Look at Fig. A.6 in the 1976 NAS report "Understanding Climate Change". In 1975 the "normal" zero reference temperature was 14.9°C; the 1938 anomaly was about +0.6. This makes the 1938 NH absolute temperature ~15.5°C (59.9°F). Compare the NAS Fig. A.6 with this chart based on similar data: http://revolution2.us/content/docs/global_cooling/614-615.html Even though 1975 is centered in the current 1961-1990 "normal" base period, the northern hemisphere reference "normal" today is lower by 0.3°C at 14.6°C (58.3°F). With the 2009 NH anomaly around +0.5°C this makes the 2009 NH average only 15.1°C (59.2°F). That is 0.4°C BELOW the measured 1938 highs. Looks like in the ~50 years from 1885 to 1938 temperatures gradually rose, and then they gradually declined back to "normal" in the mid-70s before starting another gradual climb. It looks much more cyclical than the long, gradual upward climb depicted in current charts. [BTW, 59.2°F for the NH in 2009 is more than SIX degrees warmer than the US in 2009 (52.9°F)]. Maybe Tom is right that the US record doesn't matter.]
  48. 10 key climate indicators all point to the same finding: global warming is unmistakable
    (Oops, I hit Submit instead of Preview. Anymoo, the question is still the same.)
  49. 10 key climate indicators all point to the same finding: global warming is unmistakable
    OK, so I really have NO idea where to post this, but since it's the exact opposite of what this thread is about: Reecntly, I was asked (well, gently bullied would be closer to the truth :D) to do a guest blog about climate after providing a couple of answers I stoled from SkS. Since there are already quite excellent articles / sites about "10 most used skeptic arguments" or "10 myths about climate change", my idea was something like "10 key skeptic peer-reviewed studies surviving longer than a few months before being totally trashed". So far I have Friis-Christensen (1991), which isn't really close to 10 yet. Any suggestions? PS @ John & other mods: if you know a better thread to post this, please tell. I really won't mind. :)
  50. Three new studies illustrate significant risks and complications with geoengineering climate
    Figure 3 has been corrected.

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