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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 104201 to 104250:

  1. Are ice sheet losses overestimated?
    Agnostic (#8), IDK, but IMHO... Rising sea levels will result in property loss and in some areas mass migrations, and this will take place over many decades to centuries. In contrast, shifts in temperature and rainfall patterns, and ocean acidification will affect, and almost certainly in a negative way, where, and how much, food can be grown. The latter changes are taking place now and can change in just a few decades, or even less if a tipping point is reached; personally, I see the latter as a larger threat. I should probably defer any follow-up to the topic of climate change costs.
  2. Naomi Oreskes' Merchants of Doubt Australian tour
    @ John Harrington #32 Some personal perspective... There is an old truism that holds that academic debates can get as vitriolic as they do precisely because there is so LITTLE at stake. I can imagine that in certain corners of certain fields there can be a bit of bullying primarily because the outcome concerns very few people and bullying pays. The same scenario is possible in any walk of life with similar paramters(although it doesn't really occur often if you think about it). That said, in my 25 years in science I have never seen anything on the scale you describe. I have certainly seen personal biases and conflicting personalities play a role in scientific exchanges (some much more unjustifiably aggressive than evident in those darn climategate emails) - but in the end it is the intellectual/empirical side that eventually holds the field in those exchanges. That's what matters. That result is possible because in my science, as in climate science, it is impossible for one person to gain much control over opinion precisely because there are a reasonable number of peers working in the field. Scientists hate despots more than most people -- scientists are usually fierce individualists, and the abuse of power conflicts with the free flow of scientific ideas. I also know that if I work on a problem or an approach that is outside the mainstream, I have to work a bit harder to gain acceptance. I don't complain about it -- that is as it should be given that scientists should be critical. But, in the few times I have followed that less trodden path in the past, I have never once felt that I have been blackballed or censored for my positions. Not once. It is very hard to get any consensus in science on anything without overwhelming evidence in one direction or the other. Those who claim that there is some conspiracy among scientists regarding AGW (by which I mean CO2 effects on climate) have no clue how the process works or how fiercely independent scientists are in general (or they depend on others not knowing).
  3. Are ice sheet losses overestimated?
    Oh, maybe it is the case that previous studies have larger estimates for isostatic rebound than Wu, et al, 2010.
  4. Are ice sheet losses overestimated?
    I'm having a problem at the conceptual level with all this; maybe someone can help. Let's say you assume no isostatic rebound and you measure a certain loss of ice mass, I, using GRACE. Under this assumption, Total loss = I. If the mantle is rebounding, some of the ice mass lost is being replaced by mantle mass; let's call the mantle mass M. Under this assumption, T = I - M. That is, the total measured mass loss is whatever is lost in ice, minus whatever has been replaced by rock. If the mantle mass rebounded perfectly with the ice mass lost, there would be zero measured mass lost. Changing the formula around trivially, you can say, I = T+M. The data regarding mass loss from GRACE (T) hasn't changed; so, I don't yet understand how introducing a rebound effect can reduce the estimate of how much ice has been lost.
  5. How significance tests are misused in climate science
    In Schmidt and Manns response to Mcshane and Wyner, Schmidt and Mann calculate a 99% probability of the last decade being the warmest in the record using the Lasso stastical technique from MW. They then discount that probability to likely (66-90%) claiming unidentified measurement uncertainty and possible systematic errors (page 3). When they discount their statistics that much, does the difference between Bayesian and Frequentist really amount to anything? If climate scientists use frequentist statistics and then discount the result to account for unknown errors they will still have conservative estimates of the actual effects.
  6. Naomi Oreskes' Merchants of Doubt Australian tour
    @David Horton, I had meant to make clear, but apparently didn't, that the conversation happened in the course of discussing global warming. No, I certainly don't intend to imply that that's what is happening with global warming science. That was her implication, not mine. I'm not a denialist of any kind. I accept the science, and always have. I came here because, as I said, I wanted to hear from practicing scientists who could offer their experience to counter the claims of my scientist-manque acquaintance. I wanted this because a friend was present who was taken in by her description of "modern science" and I'd like to offer him another perspective.
  7. Berényi Péter at 01:59 AM on 17 November 2010
    How significance tests are misused in climate science
    Maarten, statistics is never used in natural sciences in a way you put it. That is, it simply does not make sense to talk about the probability of hypotheses being true (or false). It's either true or false. Of course it is entirely possible we are ignorant about its truth value; in that case one should say I do not know (a perfectly legitimate scientific stance), but it surely has a truth value, even if no one was able to determine it so far (provided of course the hypothesis makes sense in the first place). The Bayesian method you describe could only serve as a heuristic device, but only if we had clear (quantifiable!) picture of prior probabilities regarding our own ignorance. That's almost never the case. If we knew how ignorant we were (having a reliable structural model of our own ignorance), most of the job required to overcome this ignorance would already be completed. However, when heuristics is most needed, we are at the edge of utter darkness, just feeling our way around, not even equipped to make educated guesses about Bayesian priors of our own state of mind regarding the subject matter. In cases like that almost any fractional understanding is better than fake formal methods to arrive at a reasonable conclusion regarding the way forward. It may be different for decision makers (like politicians or business people) who rely on expert advice in certain matters, but are not equipped to actually understand and evaluate the detailed reasoning behind those expert opinions (they only digest the executive summary, anyway). They may well wonder how likely it is the experts have got it right, and in complicated cases it makes perfect sense for them to seek a quantified description of uncertainty. To ask an independent group of experts to give an estimate of prior probabilities and build a Bayesian model to evaluate reliability of expert propositions may be a way forward. However, in practice extra rounds like that are seldom better than honest expert meta-opinion, expressed in plain language. There is a more restricted domain where statistics can (and do) come into play in natural sciences. That's measurement laden with noise. However, in this case there is no room for theoretical ambiguity. We should know pretty much everything how the signal we are looking for is supposed to look like along with the statistical properties of noise behind which it is hiding. This knowledge should take the form of a bunch of true propositions about the phenomenon under scrutiny, neither of which has a dubious truth value expressible in a probabilistic form. If this knowledge is given, we should be able to build an adequate statistical model which enables us to recover the signal from noise as much as possible. Of course the first thing to do is not to rely on statistical speculations, but to improve the signal to noise ratio of measurement whenever it is practicable. Unfortunately in climate studies most of the noise is not from the measurement procedure itself, but it is weather noise, that is, an inherent property of the system itself. There is no way to get rid of it during the measurement phase. Weather is an open thermodynamic system, and as such it works on the edge of chaos, in other words it is always in critical state (by way of SOC - Self Organized Criticality). Systems like this are characterized by system variables with pink noise characteristics (the noise has random phase and the same power in each octave). Pink noise is scale invariant with no lower cutoff frequency, therefore system variables like this do not make a natural distinction between weather and climate, no matter how long is the averaging window used (how low the upper cutoff). Pink noise is never stationary, it has an arbitrarily long autocorrelation scale. This is why it is a bit tricky to look for trend (as signal) in a climate variable laden with weather noise. A simple model of a linear trend plus some stationary noise would surely not do (even if mainstream climate science is almost always guilty of using such simplistic models). Pink noise can have spontaneous excursions on all scales, including extremely low frequency ones (well in the supposed climate range of 30+ years). You say "A standard answer [to the question if temperatures are rising or not] is to calculate a temperature trend from data and then ask whether this temperature trend is “significantly” upward; many scientists would then use a so-called significance test to answer this question. But it turns out that this is precisely the wrong thing to do." Yes, but it is not wrong just because the result of an otherwise correctly applied significance test is misused, but in most cases people also apply the wrong significance test (that fails to take into account the very long autocorrelation timescale). The above statements on weather (or climate) noise, critical state, self-organized criticality, pink noise, etc. are simply true statements with no further qualification whatsoever. It is not likely they are true, not even 100% sure, they are simply adequate descriptions of certain aspects of the behavior of open thermodynamic systems with many degrees of freedom. Still, they are entirely missing from IPCC reports, prepared by experts for decision makers. Phrases like "pink noise" (or "1/f noise") are not even mentioned under http://ipcc.ch. Funny.
  8. A detailed look at galactic cosmic rays
    On the issue of GCR Cloud Seeding You seem to have completely ignored the body of work by Harrison and others who have made in situ cloud observations which "are consistent with enhanced production of large cloud droplets from charging at layer cloud edges." There's an example of their work below but also many more from what I can see in literature searches. Harrison and Maarten 2009
  9. Naomi Oreskes' Merchants of Doubt Australian tour
    @John Harrington #32 (BTW I am not a practicing scientist, I am an engineer and speaking from my point of view) In view of all technological progress made in the last centuries, I would say in general the scientific process seems to work pretty well. If we only look back 100 years, we can see how much our world has changed thanks to the new insights developed by the scientific community. This is not so much due to individual scientists – although of course talented scientists can have a big impact – but it is mainly due to the scientific process, that validates, connects and consolidates knowledge. Many things we take for granted nowadays wouldn’t be around without this scientific process. For instance: cars, airplanes, spaceships, television, cell phones, computers, robots, all sorts of electronics, medicines, operating equipment, power plants, … Non-scientists generally don’t have a clue as to what tremendous combined effort in various disciplines has been necessary to develop these products. I am thinking of materials science, crystallography, astronomy, mechanics, electronics, information theory, electromagnetism, quantum mechanics, thermodynamics, chemistry, biochemistry, chaos theory, etc. If it were true that "science is about dominant factions of science bullying those who disagree" you would never see this kind of progress. Actually, you would see no progress at all. I rest my case.
  10. How significance tests are misused in climate science
    Thanks for the insights Maarten. I searched your work on Web of Science. It looks like you'd have heaps to contribute if you felt so inclined. The cloud ionisation work with Harrison caught my eye. The most recent article on SkepticalScience about GCRs seems to have neglected the insights from Harrison's work. (Apologies for going OT)
  11. Are ice sheet losses overestimated?
    Cryosat-2 *should* be able to help very much although it will still have its downfalls like the other methods. Ultimately what you will see is that Cryosat-2 data will be probably the most important dataset in the future for ice sheet change detection. That being said, I could never see radar interferometry not being useful as it is the only method that can actually detect and measure when flow increases from outlet glaciers. The problem with radar interferometry though is that you can measure the outputs, but knowing the thickness of glaciers and how much snow comes in, is more difficult. All in all, cryosat-2 is going to be a great tool but there will probably be hiccups initially.
  12. Are ice sheet losses overestimated?
    Re: oamoe (9) Yes. Cryosat-2's primary mission:
    "ESA’s Earth Explorer CryoSat mission, launched on 8 April 2010, is dedicated to precise monitoring of the changes in the thickness of marine ice floating in the polar oceans and variations in the thickness of the vast ice sheets that overlie Greenland and Antarctica."
     The calibration phase should be complete and full-service data collection begun. The Yooper
  13. Are ice sheet losses overestimated?
    Will Cryosat be able to clarify this situation?
  14. Climate cherry pickers: cooling oceans
    "What we do know, and have measured, are not absolute TSI's and forcings, but rather time-resolved points of deltas in forcings; when they have changed to some extent." Even our knowledge of TSI has been based on significant and invalid assumption. Haigh et al. using the new SIM data show that where we thought a decrease in "TSI" should mean decreased radiation reaching the surface, the makeup of the TSI matters and is non-intuitive and not previously measured. This new knowledge could have significant ramifications to climate science.
  15. Climate cherry pickers: cooling oceans
    KR #35 & kdkd #36 Had a look at the ACRIM and PMOD satellite TSI series. It is a somewhat confused picture with ACRIM Composite being written up as the best of the ACRIM 1,2,3 satellite reconstructions compared with PMOD which is somehow model based. Even then ACRIM produced a positive trend over the last 30 years equal to about +0.1W/sq.m (0.04%)solar radiation at the surface, whereas PMOD seems a negative or no trend. My main point was that none of these reconstruction uses SORCE TIMS or can explain the -4.5W/sq.m absolute difference in TSI. In fact the SORCE people produced their own Earth's energy flux balance chart (a la Dr Trenberth's famous chart) based on a TSI of 1361.5 W/sq.m rather than 1366 W/sq.m. Apparently it was crap according to a leading climate scientist. Your point about differences and deltas being the important determinant of trends is correct, provided we know what is happening at start time T1 with the particular forcing we are examining. Overriding this is BP's point that when you look at the satellite TOA imbalance data for the 2002-04 period there is no significant delta at all, see here: http://www.skepticalscience.com/news.php?p=2&t=107&&n=178#12580 when OHC content charts quoted above show a big leap. That is why high precision (month-month or year-year with same instrument) but low accuracy satellite data must be looked on as much more reliable than transitional XBT-Argo data measuring OHC. kdkd makes an interesting point. Clearly we have to try and pick winners here. Sort which data is crap and which might be close to correct. When there is conflicting data - the method is to look at its nature and try to find logical reasons why one might be good enough to be useful and the other not so. Satellite deltas verses XBT to Argo transition is a no brainer I would have thought.
  16. Naomi Oreskes' Merchants of Doubt Australian tour
    The message of the book is that these people that do things for their (weird) ideological reasons. These people are good enough for the special interests. In fact, any denier voice is good enough for the special interests. The special interests are not in for the science. They just want to keep polluting and getting away with it.
  17. Climate cherry pickers: cooling oceans
    KL #34 You can't have your cake and eat it you know. Making (correct) claims that particular measurements are too imprecise to be terribly useful is one thing. Following on from that your argument then assumes that these measurements have a very high degree of precision (or at least we can ignore the uncertainty). This by itself invalidates your argument. There may be a useful contribution you can make here, but at present it appears to be through (like BP) being a useful case study of the faulty reasoning of so-called climate sceptics.
  18. How significance tests are misused in climate science
    Dear Eric L., In my opinion you are making too much of the frequentist vs Bayesian discussion. I think it is not that central to whether you think significance tests are useful or not. Also a frequentist would agree with the statement that the p-value does not contain enough information to calculate the probability of the truth of a hypothesis, or the null hypothesis (such statements can be perfectly well framed in frequentist terms). Regarding the dendrochronologist, this is an example that is very interesting. Equation 6 in my paper states how to view this. It is simply Bayes equation written in terms of prior and posterior odds: posterior odds = prior odds x p(M| not N) / p(M|N) where I used the notation as in the post above (note the p(M|N) is the p-value). So whether your confidence in the global warming hypothesis has been increased by your tree work depends on whether the p-value is smaller than the probability to see your measurement in situations that we know there is global warming. This statement is independent of the prior odds; the actual posterior odds of course do depend on the prior odds. In other words, every single measurement increases our knowledge (changes our confidence in a hypothesis) in the same way; this is independent of whether you were a "believer" or not to start with. This discussion is getting quite long now. I will probably write another post with some of this stuff in sometime soon where I can also comment on the suggestion by HumanityRules. I think John Cook agreed that I could send in another guest post about this subject anyway. Best wishes to all and thank you very much for your interest in this post and for an interesting discussion, Maarten Ambaum
  19. Ice-Free Arctic
    muoncounter you should distinguish between BC absorption in the atmosphere and on the ice surface. I was referring to the latter which directly influences the ice melting.
  20. Naomi Oreskes' Merchants of Doubt Australian tour
    Oh and John Harrington at #32 - why, I wonder, would you repeat an anonymous anecdote like that, and, what's more, to use it as an example of "how science works" in general? It couldn't be, could it, that you are intending the reader to say "Oo yes, that must be what is happening with global warming, all the honest skeptics are being bullied, so the truth can't come out." That wouldn't be the intention would it John? I have been a scientist for over 40 years - the scenario you suggest is nonsense.
  21. Naomi Oreskes' Merchants of Doubt Australian tour
    The list of things attacked don't just have in common the people doing the attacking (eg Singer), and the methods used (down to a fine art, or what?), but also the nature of the argument. In every case these people are determined that (a) nothing will get in the way of business and (b) that nothing humans do can possibly damage the planet (or themselves). There is no doubt that the opposition is ideological, and business-related, nor any doubt that the techniques used, and the motives for using them, are found on blogs all over the world, including, not least, this one.
  22. Economic Impacts of Carbon Pricing
    I’m agnostic about which method should be used but I lean towards Cap & Trade if it’s done right. Part of right is a meaningful cap and no (or few) free allocations handed out at start-up. I worry somewhat about the trading mechanism (will we have CO2 derivatives?) but I think the biggest issue is measuring the emissions of all the players to see that they actually stay within the allocations they purchase. It’s workable when the number of players is relatively small, as was the case for sulphur emissions by power plants to combat acid rain. I don’t have the expertise to assess whether society can monitor GHG emissions with the necessary resolution – player by player – though I think so for the larger players. And I don’t know that the idea of returning C&T revenues to the public coffers to reduce taxes is really productive, as some have suggested be done. That just removes the capital from the innovation process that will find new low emission means of energy production, manufacturing, etc. and the subsequent updating to use that new technology. It just prolongs the problem. Can others fill in some of the blanks?
  23. Climate cherry pickers: cooling oceans
    Ken Lambert - Actually, there is considerable and ongoing effort in merging together and cross-calibrating TSI series, as I have referred you to previously. See here and here. Those are the top two results from googling "satellite TSI", hardly difficult to find. Your statement (that TSI measurements aren't being merged) is simply not correct. On your other argument, regarding time integrated TOA imbalances - I consider the closed loop integration you have been pushing to be overvaluing the accuracy of the various measurements over the last 150 years. You don't seem (IMO) to be treating the TSI, TOA infrared, and various forcings with the caution needed given the accuracy of our knowledge, and interpolate from 1750 on assuming perfect accuracy. That's simply not supportable. What we do know, and have measured, are not absolute TSI's and forcings, but rather time-resolved points of deltas in forcings; when they have changed to some extent. And we can correlate those with multiply-supported temperature changes to determine the dominant forcings and responses over time. Your black-box integration from 1750 on (assuming perfect knowledge) leads to contradictions with deltas, orders of magnitude, and observed responses. You are simply too focused on what you see as absolute values.
  24. Economic Impacts of Carbon Pricing
    SoundOff@36 & Composer99 @ 37 The main advantage of market solutions such as C&T and carbon tax is that it internalise external costs into the cost of the polluting process. For that reason, this approach for dealing with externalities is preferred by most (neo-classical) economists over the regulatory approach. Businesses on the other hand tend to prefer regulations as they generally have the lobbying power to influence the design and implementation of regulation and make it as "toothless" as possible. Pricing carbon on the other hand (either through a carbon tax or using C & T) means that the cost of polluting has to be met and passed on. This is one of the reason why conservative political parties (eg the opposition in Australia) favour regulation and resist the adoption of a C & T scheme. They prefer calling it a "carbon tax" as this sounds very "evil" when it is actually a market based solution.
  25. The Skeptical Chymist at 15:54 PM on 16 November 2010
    Naomi Oreskes' Merchants of Doubt Australian tour
    John Harrington 11.42 AM While it is true that genuine areas of scientific debate/disagreement can get heated and divisive, the story you relate seems very outlandish. I would also disagree with her view of "modern science". Getting papers through peer review can be hard and the system doesn't work perfectly, but it's neither a sham nor corrupt.
  26. Economic Impacts of Carbon Pricing
    Might I add that government/international regulation of pollutants (either a cap and trade on sulphur emissions or the phase-out of CFCs has been succesful in the past. As such, there is no a priori reason why some effort to regulate carbon emissions in a similar manner is destined to fail. Further to SoundOff's comment #36, airport security is as bad as it is because governments perceive the need to be seen doing something immediately. This leads to such wonderful ideas as full-body scans. Personally, I'd prefer that they take steps now, carefully and rationally, to do something about greenhouse gas emissions instead of trying to be seen doing something about them in a panic in 10-15 years.
  27. Naomi Oreskes' Merchants of Doubt Australian tour
    sout: There is a huge amount of 'value added' by meeting people in person and having hundreds of people come together to listen and discuss face to face. Agreed, and I think this is especially true of Q&A segments. That's often the most important part of these events, and it's much harder to connect with audience members — undecided ones, especially - through videoconferencing. It's very important to do presentations like this one in person, IMO (and to make the footage widely available online, during and after).
  28. Naomi Oreskes' Merchants of Doubt Australian tour
    johnd: Phila at 10:51 AM, the point I was making is that perhaps there are other problems that may reach a crisis point well before any climate change realistically impacts to any great extent, and priorities and attention be adjusted accordingly. So I gathered. Regardless, it's a false dichotomy, not least because some of these problems have the same root causes or ideological obstacles, and the same people counseling inaction and complacency (or recommending that we shift our attention to "real" problems, a la Bjorn Lomborg). If people need to feel better being described as "needing to address" Since my comment had nothing to do with how people "need to feel," this reply is puzzling. My suggestion was more for your benefit than anyone else's, and was less about making other people feel better than helping them (possibly) to take your statements a little more seriously.
  29. Miriam O'Brien (Sou) at 14:21 PM on 16 November 2010
    Naomi Oreskes' Merchants of Doubt Australian tour
    In response to comments about a webcast or similar being preferable to a tour, I have to say the Oreskes is getting a large amount of publicity here that she would not have garnered from a webcast; including on national radio and television. I agree (and promote the use of) video conferencing - eg for meetings of national and international groups - for dealing with ongoing matters. But only if there are also regular (if less frequent, eg annual) face to face meetings. There is a huge amount of 'value added' by meeting people in person and having hundreds of people come together to listen and discuss face to face.
  30. Climate cherry pickers: cooling oceans
    BP #26 Some knockout points BP. I am indebted to you for opening my eyes to the OHC story and the impossible jumps and bumps in the von Schukmann graph and the critical point that OHC increase must be the integral of the TOA forcing imbalance wrt time to be consistent with the first law. The impossible jumps OHC in the 2003-04 period can only be explained by dud Argo measurements OR as an offset - an artifact of the transition. My contention is that Argo is also not perfect and the 'gold standard' is a tethered buoy system measuring the same tile of ocean at the same referenced time T1 and again at T2 all over the planet as the only accurate way of measuring OHC differences over the T2 - T1 period. How close Argo comes to that 'gold standard' no-one seems to know. The SLR graphs showing TOPEX spliced to Jason also are candidates for offsets at the transition where the SLR slope has reduced with Jason compared with TOPEX. Strenuous effort has been made by AGW protagonists to claim that these transitions are calibrated to be seamless, however the point is made that the latest satellite instruments must be more accurate and repeatable than earlier instruments with diferent gains and inferior technology. Also no-one is seeming to splice TSI measuring satellites together into a continuous record probably due to a -4.5W/sq.m unresolved difference in the latest SORCE TIMS satellites and prior measurements by earlier satellites. That is one helluva offset.
  31. Economic Impacts of Carbon Pricing
    Some believe any government intervention puts us on slippery slope to world socialism. If they admit climate change or warming is occurring and has human causes, then they also admit the need for government intervention. They won’t do that. The irony is that the more they delay political and economic action to correct this problem, the greater the crisis will become and eventually much more radical government interference will be needed than if we had started addressing the problem earlier. Imagine, perhaps, CO2 rationing. We only need to look at airport security today to understand how much governments will spend when they perceive a matter to be urgent, and the freedom we will lose in the process.
  32. Ice-Free Arctic
    #73: "doesn't tell much about the causality between the two." Hopper et al 1994 reiterate my point in #71 ... hourly black carbon data exhibited considerable episodic behaviour over periods of a few days to a week. These elevated concentrations of black carbon were most often correlated with increases in carbon dioxide and methane concentrations. Such correlations can arise from several causes, but transport of a polluted air mass from industrialized regions to the high Arctic would account for the simultaneous increases in numerous monitored constituents, and is consistent with previous studies of Arctic Haze. Black carbon is apparently a valid 'tracer' for carbon dioxide. BP in his considerable wisdom now strengthens the link between Arctic melt and atmospheric CO2. To take this one step further, black carbon transport is apparently affected by ocean oscillations. From Sharma et al 2006: The results revealed that EBC concentrations were 40% higher during the positive phase of the North Atlantic Oscillation than during the negative phase. The source contributions at the two sites were determined by using trajectory analysis techniques, which revealed that Alert came under the influence of Siberia/Europe transport while Barrow showed influence from Siberian and Pacific/Asian transport. This suggests the end of the 'its all because of ocean oscillations' tripe. The varying wind and weather associated with ocean oscillations are merely the agents that modify the transport of GHGs from anthropogenic sources to the Arctic.
  33. Naomi Oreskes' Merchants of Doubt Australian tour
    Phila at 10:51 AM, the point I was making is that perhaps there are other problems that may reach a crisis point well before any climate change realistically impacts to any great extent, and priorities and attention be adjusted accordingly. If people need to feel better being described as "needing to address" rather than agonising over many of the issues whilst little is being achieved, or wringing of their hands, then perhaps that is the most telling point of all with regards to being able to set priorities.
  34. Naomi Oreskes' Merchants of Doubt Australian tour
    JohnHarrington. That sounds less like "how science works" than how any workplace can go wrong. How many people do you hear grumbling about dopey or biased or bullying management in any activity? Quite often there's something in it. Two things to consider. One, it may be true, but not nearly as often as unsuccessful people blaming others for their own failures. Two, the fact that one person / manager / senior scientist is a pain in the neck or any other part of the anatomy says more about that person than it does about the field of endeavour. What this woman said might, possibly, be true about the person she was dealing with or about that particular sub-specialty. It says nothing about the larger field of science generally and it certainly does not lead to conclusions about greed or Nazism or Lysenkoism or corruption or any of the other general criticisms of science. (My personal view is that anyone who plays the Nazi card automatically deals themselves out of the game.)
  35. Naomi Oreskes' Merchants of Doubt Australian tour
    Excuse me if this is too off the topic. I really don't know where else I might post this. I was debating someone at a party recently who opined that "science is about dominant factions of science bullying those who disagree". The person saying this claimed to have a PhD in archeology and to have escaped the field in part because a rival scientist got her in trouble with a foreign government, which caused passport trouble, simply because she disagreed with this scientist's hypothesis about horse domestication. She went on to compare "modern science" to science done in Nazi Germany and to suggest that peer review was a sham, made venal by government monies in science. I'm not a scientist, as I was forced to admit, and this made her seem like the authority who was giving me the truth about how "science really works". I wonder if any practicing scientists posting here could comment on this view of "modern science".
  36. Are ice sheet losses overestimated?
    One thing is clear from this excellent summary. Ice loss in polar regions is occurring and getting faster. No surprise to anyone. It also focuses attention to the fact that we need (and presumably will get) more information, particularly on the extent to which ice loss is now and will in the future contribute to the most dangerous aspect of global warming – rising sea levels.
  37. How significance tests are misused in climate science
    Dikran (@37), Perhaps I just need to see an example of Bayesian significance testing done right to understand the way you and Dr Anbaum think this should be done. "one of the most important benefits of the Bayesian approach is that it gives mechanism to properly incorporate the fact that you know you don't know something, by assigning a non- or minimally-informative prior on it and marginalising it out of the analysis" Does a Bayesian analysis with a minimally informative prior often lead to a different result than a frequentist approach? I must confess that my knowledge of Bayesian statistics comes entirely from studying data mining/machine learning, so there may be a side to this I'm missing from not having studied more stats. In that class one thing we were taught is that if you don't really know the prior the most common thing to do is assume it's 50/50. Is that the sort of thing you mean by minimally informative prior? "Bayesian conclusions are only as strong as the priors used, if you could show the priors were unreasonable then you could reject the result of the test (and the paper). If you can't question the prior, you are logically forced to accept the result of the test." It still seems to me to be a question of what the point of the work you're doing is and what you can add to the body of knowledge. Let's assume I am an expert in dendrochronology, and I core a few trees in my backyard. Now I need to calculate a prior probability for observing warming in that data set. One way I might do that is by looking at the evidence from atmospheric physics and other areas outside my expertise and decide how likely this should be, but why would I be the one to do this when that really isn't my field and I'm likely to screw it up, I just know all there is to know about tree rings? Or are you suggesting I use a non-informative prior? Let's say I did the full analysis and found that with 99% confidence given changes in various forcings and our range of sensitivity estimates the data should show an upward trend of .15 degree/decade or more. And then I did some calculations on my little data set that any frequentist would sneer at and calculated a posterior probability of 99% for my hypothesis. Have I used my knowledge as a dendrochronologist to contribute anything to the state of our knowledge about climate? My result comes from my prior calculation, the part of my work I'm least qualified to do, meanwhile the actual data I've collected is superfluous (and I should have collected more of it, as a frequentist statistical significance test would have told me). I do think a Bayesian analysis by someone who was an expert in such things that combined varous lines of evidence from many subfields of climate research and tried to establish probabilities for various climate related hypothesis would be an interesting work, but it's not reasonable or useful to expect every researcher to do this in the process of establishing their result, and indeed Dr. Anbaum's research shows pretty conclusively that most would not be competent to do it. If on the other hand you want most scientists to replace frequentist significance tests with Bayesian tests with non-informative priors to show they've learned at least that much about stats and know what their confidence values mean, I guess I'm okay with that, but I doubt it would change anyone's results much beyond changing the confidence values by a small amount. I do think scientists should not put their confidence values front and center as if they are the results, better to focus on estimating the magnitudes of effects, but do some kind of confidence calculation just to keep yourself honest and make yourself less likely to publish garbage. But if you think that's the main value that comes from confidence calculations in science (and I do) rather than determining whether we should be 96% certain or 99.3%, then a frequentist approach will generally work okay and if the result is your paper leads people to believe that climate sensitivity is 3.2 when you really do have good reason to believe it is 3.2, then your paper isn't particularly misleading just because there may be a better way you could have done your confidence calculation.
  38. Naomi Oreskes' Merchants of Doubt Australian tour
    quokka... This is exactly my point as well. We would all love it if we could jump on a jet airplane that was burning algae based bio-fuel that was being produced at a cost comparable to current jet fuel. I'm sure Al Gore would be the first to book limousine service from a company who had an all electric fleet. We are not there. (We don't have the vegetables for our veggie diet.) We need people like Oreskes flying around doing these tours to promote her book. We need politicians flying to Copenhagen for such events. To stop - or even slow this process down - is to stop the process of addressing this issue.
  39. Naomi Oreskes' Merchants of Doubt Australian tour
    johnd: That is the real problem coming that people should be wringing their hands over. This seems like a false dichotomy. Acknowledging the problems you mention does not require us to see AGW, or any other problem, as less than "real." Also, "wringing their hands" has a rather contemptuous sound. Saying something like "a problem people also need to address" might be a bit more constructive.
  40. Naomi Oreskes' Merchants of Doubt Australian tour
    #16 KeenOn350 There is a carbon cost on just about any activity - from eating your lunch to building wind turbines or nuclear power stations. The point surely is to spend that carbon wisely. As far as I am concerned, the trivial carbon costs associated with Oreskes tour is a very wise expenditure of carbon indeed. If Oreskes, Hansen and other outstanding individuals want to fly around the world 100 times a year in the political fight against AGW deniers and that activity can bring forward an organized collective effort to reduce emissions by even a tiny amount, then that carbon cost would be repaid by orders of magnitude. Youtube videos are no substitute for physical presence. Why do people like live music? Why do we still have teachers in classrooms?
  41. Economic Impacts of Carbon Pricing
    Eric (34), if you are a "skeptic" about government spending, then you should equally advocate a cap-and-trade bill or a carbon tax while demanding tax cuts, not just scrapping economic action against climate change altogether. "Government wastes money" is a poor excuse and just amounts to a simplist libertarian pirouette against taking action against global warming just because the Gov't is involved. Reasonable libertarian-leaning economists support cap-and-trade (for example, Tyler Cowen). There are even some cap-and-dividend proposals which involve directly handing over the money to the citizens, therefore deflecting your critique. One small remark: "> The IGEM model is an outlier because it assumes when the price of energy (and other goods and services) rises, people will respond by choosing to work less than they otherwise would (EDF 2008). This is a counter-intuitive and illogical assumption, since increasing costs generally result in people working more to increase income correspondingly" Actually, this is a bit more complex. Economic theory says that price changes have _both_ a "substitution effect" (if working is less useful, people work less) and an "income effect" (if work "pays less", people will try to work more in order to "offset" its effects). Both effects do exist in the real world, and which effect is stronger depends on a lot of things and it is an empirical question rather than a theoretical one. AFAIK some economists find a significant substitution effect in the economy as a whole (Prescott) while others report a smaller one. I don't know in depth what does the literature say, but I wouldn't go so far as to declare substitution effects "illogical" or "counter-intuitive". They're just as real as income effects, the real question is whether they are big or small. This is relevant for a number of reasons beyond climate change (tax policy, for example).
  42. Naomi Oreskes' Merchants of Doubt Australian tour
    Argus wrote : "Is there any follow-up report available yet?" Well, to stop going further off-topic, I can start you off and you can then find out further information for yourself hopefully : Brick Kilns
  43. Naomi Oreskes' Merchants of Doubt Australian tour
    Re: CBDunkerson (8:05 am) I like to think that there will be a future civilization, when global population has been stabilized at around 1.5 - 2 billion, and most energy is green, and lifestyles are equitable globally (i.e. most residents of future Africa, India, etc., have a lifestyle comparable to most residents of the future USA), and that those lifestyles for all will be, in many ways, similar to those of today. I like to think that in the very near future, we will take some control of our destiny in a more rational fashion, to deal realistically with the crises we face (of which climate disruption is only one). I like to think that we may have a rough landing, but it won't be a crash. But meantime - planet Earth, we have a problem. The scale is greater than that of WW II, the threat may be greater than (or may include) WW III. In WW II, people accepted the need to constrain their lifestyles and consumption habits to address their problem. (They also accepted a lot of government controls - voluntarily, understanding the need.) I see no way that we can address our multiple problems effectively without accepting similar constraints for the near future, given that we have wasted 40 years or so. Had we started to address the two major problems of clean energy and population growth effectively in the early 1970's ( when both problems were already in evidence), then I would be more inclined to agree with you. Given where we are today, and what seems to be in the international plans for the near future (not much!), lifestyle changes will be coming. As John Holdren has said - "We basically have three choices: mitigation, adaptation and suffering. We're going to do some of each. The question is what the mix is going to be. The more mitigation we do, the less adaptation will be required and the less suffering there will be." Right now we seem to be opting for the suffering - i.e., a serious and forced change in lifestyles, which will, before long, affect those of us in the USA and Canada, as it is now affecting many in other parts of the world.
  44. Naomi Oreskes' Merchants of Doubt Australian tour
    JMurphy (#23): "To ensure the conference will be climate neutral, the Danish Government, ..." That is good news, thank you, I did not know about those plans. I hope they went through with the programme, and that it worked out as it was planned a year ago. Is there any follow-up report available yet?
  45. Ice-Free Arctic
    Berényi Péter comparing summer ice extend to visibility in Hong Kong doesn't tell much about the causality between the two. Probably there's not. More relevant could be meaurements BC concentration in ice cores. It's in Central Greenland, not over the arctic ocean, but it clearly shows (fig 2a) that BC deposition there went through a quite large peak around 1910 and then declined. In the last decades, though, it's slowly increasing again, but still well below the peak.
  46. Are ice sheet losses overestimated?
    Stephen@5. I doubt we can 'protect' science, scientists or their individual publications from misuse or attack. I'm afraid it's really for us and the scientific community to support wherever possible. When we're stuck walking in the rain, we share the umbrellas, we keep trudging on and we make maximum use of every little bit of dry shelter with gratitude. And we keep each other's spirits up.
  47. Naomi Oreskes' Merchants of Doubt Australian tour
    CBDunkerson at 08:05 AM, whilst some may feel content to continue existing lifestyles if energy production changes to low CO2 alternatives, what goes hand in hand with energy usage in lifestyles is that other form of energy, namely food. This is perhaps the real problem that should be addressed as so far, unlike the nuclear option for power generation, there is no alternative for the essential nutrients that are stripped from the soil to produce the food, be it meat or vegetables. So there should be no thought of being able to continue an existing lifestyle by phasing out fossil fuels if half the food that leaves the farm gate is going to be continued to be wasted by an indulgent lifestyle that is partly reflected by increasing obesity in the developed, mainly western world. That is the real problem coming that people should be wringing their hands over.
  48. Naomi Oreskes' Merchants of Doubt Australian tour
    KeenOn350 wrote: "This is precisely the question - who will begin to implement and to demonstrate the lifestyle changes we need? And when?" You are proceeding from a first assumption, that we must make significant lifestyle changes, which I do not agree with. In reality that is only one theoretical option, and in my opinion not a very plausible one. It seems far more likely that we will convert most of our energy production to low carbon emitting alternatives and continue with our current lifestyle largely unchanged.
  49. Are ice sheet losses overestimated?
    Great post, Robert. This is a really handy summary of where things stand right now.
  50. Naomi Oreskes' Merchants of Doubt Australian tour
    Argus wrote : "Another example of mixed messages was the Copenhagen meeting a year ago." It isn't perfect, and shouldn't be used as an excuse by anyone to do nothing at all (a la "Gore flies everywhere and burns loads of electricity in his mansion(s), so why should I do anything ?" - um, why should we judge anything by what he, or any other individual, does ?), especially because of the following : An initial estimate of overall emissions result in a figure of 40,500 tonnes of carbon dioxide. To ensure the conference will be climate neutral, the Danish Government, in partnership with Bangladesh and the World Bank, has decided to replace outdated brick kilns in Dhaka. It will see the heavily polluting, existing kilns replaced by 20 new energy efficient ones, which the Danish Energy Agency calculates will cut more than 50,000 tonnes of CO2 emissions each year and improve air quality in one of the world’s most polluted cities. The Danish government has set aside 0.7 million euro as part of this year’s state budget for this purpose. Fact sheet: Minimising the Copenhagen carbon footprint

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