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Comments 69401 to 69450:

  1. Schmittner et al. (2011) on Climate Sensitivity - the Good, the Bad, and the Ugly
    RealClimate has not posted an article on Schmittner et al. As always, it is well worth reading. I found particularly interesting the perspective given on Schmittner et al's result taken at face value in the last paragraph:
    "It bears noting that even if the SEA mean estimate were correct, it still lies well above the ever-more implausible estimates of those that wish the climate sensitivity were negligible. And that means that the implications for policy remain the same as they always were. Indeed, if one accepts a very liberal risk level of 50% for mean global warming of 2°C (the guiderail widely adopted) since the start of the industrial age, then under midrange IPCC climate sensitivity estimates, then we have around 30 years before the risk level is exceeded. Specifically, to reach that probability level, we can burn a total of about one trillion metric tonnes of carbon. That gives us about 24 years at current growth rates (about 3%/year). Since warming is proportional to cumulative carbon, if the climate sensitivity were really as low as Schmittner et al. estimate, then another 500 GT would take us to the same risk level, some 11 years later."
    Of course that extra 11 years would be extended if we started reducing CO2 emissions, and if the response to temperature change was not proportionate to the climate sensitivity (see The Ugly News above), would give as a welcome buffer in which to overcome the current political paralysis on global warming. Overall, the RC article makes a useful complement to Dana's article above, discussing as it does some issues not raised by Dana.
  2. Schmittner et al. (2011) on Climate Sensitivity - the Good, the Bad, and the Ugly
    @ skywatcher I find the key words in that phrase to be "imminent" and "extreme". The skeptic community is fond of "soft" words of varying definitions, depending upon the Humpty-Dumpty-like usage they favor (not to imply the authors of the paper in question do that). Thus "imminent" and "extreme" can be defined by the viewpoint of the reader.
  3. Economic Growth and Climate Change Part 2 - Sustainable Growth - An Economic Oxymoron?
    A few comments: 1) The economic growth indicated by the chart is a factor of 2.4257 by 2035, or approximately equal to an annual growth rate of 3.2% (1.032^28 ~= 2.42). The total annual average growth rate for OECD nations from 1990 to 2006 was 2.7%. There is no reason to think that will significantly decline in the future, although the ongoing effects of the global financial crisis will reduce that growth in the short term. In the meantime, China (10%) and India (11%), between them representing 36% of the worlds population will probably have double digit, or close to double digit growth rates for some time. This suggests the growth represented on the chart is more likely to be conservative rather than optimistic. 2) Maintaining zero growth for OECD nations while spending 1% of GDP per annum on conversion to low emissions technology represents a declining income over time. That is a political impossibility to sell, and of dubious merit in any event. 3) Economic growth, all else being equal, is a good thing. Of course, all else is not equal, but you would need very substantive reasons to not pursue economic growth. 4) In a world with rapid technological innovation, and hence frequent adjustments to employment patterns, significant economic growth is needed to provide an underlying demand for labour to employ those people who are made redundant by new technologies. Therefore zero economic growth is neither desirable, nor achievable while we pursue and achieve rapid technological innovation. 5) Large scale global trade is a prerequisite for maintaining a high standard of living in OECD nations, and for increasing the standard of living to OECD levels in nonOECD nations. However, much of that trade is driven by (and drives) economic growth. The ripple effect of OECD nations pursuing zero economic growth will be to significantly slow the rate at which non-OECD nations grow their economies. With average luck, it would trigger a major recession. 6) Clearly I disagree with perseus' main conclusion. That is in large part (as indicated above) I believe the cure could be as bad in human terms as the disease. Global warming is not going to drive humans to extinction. It is going to significantly decrease our standard of living and (in the worst cases, population). However, freezing global growth carries exactly the same risks. Perseus is not actually advocating freezing global growth per se, but freezing OECD growth with other nations allowed to play cachup will be almost as bad as freezing global growth (if effective), and barely limit economic growth if ineffective. Rather than advocating the freezing of economic growth, we should welcome economic growth that helps better fund the conversion to low emissions technology. A 0.5% economic growth that helps fund a 1% reduction in emissions intensity is a net gain in terms of reducing emissions, and should be welcomed. On the other hand, economic gains which are not coupled with reductions in emissions intensity are counter-productive. The obvious answer is to use government levers to direct growth into channels that reduce emissions intensity, rather than to set zero growth as a policy.
  4. The Debunking Handbook: now freely available for download
    If McIntyre has valuable points to make, then why doesnt he publish them?
  5. Schmittner et al. (2011) on Climate Sensitivity - the Good, the Bad, and the Ugly
    Dr Schmittner, very nice to see you commenting here. I don't suppose this will turn into a question-answer session, but if you have the time I would be very interested in your take on the last line of your abstract, and your grounds for it. Many in the mainstream media took it as cause for optimism, and I would be interested to know why:
    "[with caveat] ... these results imply lower probability of imminent extreme climatic change than previously thought."
    In relation to the "ugly" part of the post above, I'm not sure how this conclusion follows from your results? Your model uses a smaller temperature change from glacial-interglacial than other models that have generated higher climate sensitivities. This means that each degree of warming we experience now has a correspondingly larger impact and will, in your model, take us much closer to a massive climate change on the scale of a deglaciation, as Dana shows above. Regardless of whether ECS is 2C or 3C, if our warming of ~0.2C/decade gets us to the scale of a glacial-interglacial climate change sooner, then surely that will qualify as "imminent extreme climate change"? Essentially, on reading your paper, I feel I have less cause for optimism than I had before, as I would have put "higher" where you put "lower" in your abstract. Maybe I am missing something, and I'd love to be shown to be wrong!
  6. Greenhouse Gas Concentrations Continue Climbing
    It took me a while to get my head around as a non-climatologist, but the NOAA page linked to in the release helped me to understand what's going on. http://www.esrl.noaa.gov/gmd/aggi/ Yes, the answer is down to using pre-industrial levels as a reference. 350 to 390 ppm (about 10%) at first seemed too small to give a 39% increase (for CO2 alone), but it's from a pre-industrial 280 ppm, so it's more like a 57% increase. This is also sufficient to show that it is the radiative forcing that primarily contributes to the non-linearity as you were saying, OPatrick. Plug the numbers into the equations on the page and everything makes sense.
  7. The Debunking Handbook: now freely available for download
    skept.fr: "... why not consider the McIntyre's obscure and technical considerations on proxy series as a legitimate argument in a discusion of paleoclimate?" Many have considered McIntyre's arguments, and found then to be wrong in nearly (granted, not quite all) every way. McIntyre's results were deliberately inflated by himself and even more by others, yet when you dig and understand exactly what he did, you don't see an accurate argument. That he still goes on about the hockey stick nearly a decade on, after it's been independently verified many times speaks strongly of his approach to science, and does not argue for his points being either relevant or accurate, or worthy of interest.
  8. The Debunking Handbook: now freely available for download
    Well I would agree that Tamino's blog is by means in the same class as peer-reviewed paper. However, Tamino does do a good job of explaining the technicalities in the data analysis in debunking a lot disinformation. If you can follow the technical detail, then it makes Tamino a valuable resource.
  9. Economic Growth and Climate Change Part 2 - Sustainable Growth - An Economic Oxymoron?
    As a matter of luck, The oil covert that issue recently. http://www.theoildrum.com/node/8615#more In short, there is no gain in the world energy intensity since 2000.
  10. The Debunking Handbook Part 5: Filling the gap with an alternative explanation
    This series is very good. It lays out explanations about discussing that make explicit things I have sensed in discussions on various global warming threads. This site is very useful for the caulk that fills in those gaps. Often I can read a paragraph with a "mini" gish gallop, refute and fill in the gaps with a quick confirmation of my response back here. Many thanks to all involved...
  11. The Debunking Handbook Part 4: The Worldview Backfire Effect
    Steve L, on humiliation: I've never seen that work well, but I have seen "gentle teasing" work to some extent. Especially some folks who are way over the top conspiracy theorists - good hearted teasing may get you into an interesting conversation that would not occur with humiliation...
  12. What's Happening To Tuvalu Sea Level?
    victull - "That could be said of any averaged point on planet Earth's oceans, and is an essential piece of evidence for global warming." No, again you haven't been paying attention. See figure 2 - note the west coast of Madagascar and the Northern Territory & western coast of far north Queensland in Australia - sea level has fallen there. "Forgive me if I am a bit obtuse, but I don't see the point in focussing on Tuvalu as an example." No worries, let me explain. Tuvalu is a low-lying coral atoll that will be one of the first nations in the world to be submerged by rising sea level. It therefore is a poster-child of sea level rise, and consequently is attacked by "skeptics" who claim Tuvalu is not being affected. See this nasty little article from Pat Michaels for instance. "Local variations on tiny dots in the Pacific would be irrelevant I would think" How very Pat Michaels of you. That you care little for the suffering of others is simply an indictment of skewed moral values. When do we start caring? When Florida starts to be submerged? Just to be clear, I live in New Zealand, the Pacific Island capital of the world. Many of my friends and former work colleagues are Pacific Islanders. They are important, and what happens to them matters. "There is a danger that skeptics will take such emphasis on places like Tuvalu as alarmism by the global warming fraternity" It is alarming. That is simply a fact. The fantasists and wishful thinkers will no doubt resort to blimp-pointing in an attempt to distract readers. It will be a futile exercise on their part.
  13. The Debunking Handbook Part 4: The Worldview Backfire Effect
    How do we get and maintain a world view.... New report exposes massive opinion industry in China. http://elgan.us1.list-manage.com/track/click?u=38b5dc26a4d87952a5ca1675f&id=515275ef09&e=3836c8cfe5
  14. Congressional Climate Briefing - The End of Climate Skepticism?
    Standout Republican Jon Huntsman -- who ranks lowest in the polls -- may have summed up the differences best when he tweeted earlier this year: "To be clear, I believe in evolution and trust scientists on global warming. Call me crazy." Indeed, many have. Seeking to drum up conservative support, the other Republican candidates have championed their doubts about human-caused climate change in recent debates just as vigorously as they have called for the return of waterboarding for terror suspects. The entire nation is divided on the issue, according to the latest Gallup poll which shows 53 percent of Americans see global warming as a very or somewhat serious threat, down 10 percent from two years earlier. "We have got a big problem, domestically, in terms of climate reality," said Alden Meyer, director of strategy and policy at the Union of Concerned Scientists. When lawmakers cannot agree that climate change is a problem for which solutions must be sought, gridlock ensues, according to Democratic lawmaker Henry Waxman. "During this Congress, the Republican-controlled House has voted 21 times to block actions to address climate change," he said at a hearing this month. "History will look back on this science denial with profound regret." Source: “Climate change denial still runs strong in US” AFP, Nov 28, 2011 Click here to access the entire article.
  15. The Debunking Handbook: now freely available for download
    skept.fr in any case the Global Warming with the Schmittner preliminary outcome is still unacceptably too high. And really we still have to start addressing emissions reduction even it that were the sensitivity. And we also still have to address the risk factor of higher sensitivities. The this is an interesting perspective ... if the temp sensitivity is low then we are seeing a high climate change sensitivity to that small change. So it would mean things would be worse than expected. That is the risk aspect that we have to take in to account which deniers and avoiders ignore. A human trait and short coming. Media Misleads On Flawed Climate Sensitivity Study: Avoiding “Drastic Changes Over Land” Requires Emissions Cuts ASAP http://thinkprogress.org/romm/2011/11/27/376197/media-flawed-study-climate-sensitivity/
  16. Schmittner et al. (2011) on Climate Sensitivity - the Good, the Bad, and the Ugly
    Suggested reading: “How Much Will the Earth Warm Up?”, New York Times Nov 24, 2011 The focus of this article is the Schmittner et al paper and includes comments by Gavin Schmidt, Richard Alley, and David Lee. To access the article, click here.
  17. The Debunking Handbook: now freely available for download
    #16, 17 : I think you will not convince me either by extreme counter-examples (Tom) or by assessment of blog quality without clear standard (muoncounter). In fact, this is a very personal judgement: I've a limited trust in any argument based on a blog article, whatever the blog, or on grey literature, and I conversely trust science because of its high standard of evaluation for publication and its openness for comments or responses with the same standards (even if this process is not infallible, it is the best we have). Same is true for IPCC WG1 rules of publications, notably if they include IAC recommendations as IPCC staff engaged to do. Your judgements on this point are different from mine: no problem. Trust is not something we can reduced to an absolutely objective foundation, at least we must be coherent for what we trust or not. Anyway the blog question was not the principal matter of my #4 point. You correctly explained me the editorial reasons for which Schmittner 2011 deserves a more attentive treatment than others publications about sensitivity. I agree with these explanations. You also show that the canonical 2-4,5 K range is the usueal reference for sensitivity on SkS. Idem. Case closed for me.
  18. What's Happening To Tuvalu Sea Level?
    victull, presumably Tuvalu is focused on because it has one of the lowest elevations above sea level on the planet and thus would be amongst the first locations to be impacted by rising sea levels. Would it somehow make sense to study the impact of sea level rise on Mount Everest instead?
  19. Economic Growth and Climate Change Part 2 - Sustainable Growth - An Economic Oxymoron?
    One first technical point, on a detail : there is frequently a certain confusion around concentration in carbon dioxide equivalent (CO2eq) and carbon dioxide alone (CO2). The first includes all GHGs and integrates their relative global warming potential . The second deals with CO2 only considered as the main driver of warming on long term. But CO2eq is the good metric, because what is important is the total positive forcing, whatever its source. What is more complex, as Real Climate explained some years ago, is that me must also include the negative forcings when we adress the anthropogenic effect on climate. For example in RC article (2007, numbers slightly changed since this date), all GHGs forcings give approximatively 460 ppm CO2eq – already more that would be necessary for a 2K stabilization. But if you include aerosols and other negatives forcings, we’re at 375 ppm CO2 eq. The Cancun agreement supported ‘a view to reducing global greenhouse gas emissions so as to hold the increase in global average temperature below 2 °C above preindustrial levels’, but I didn’t find in the document a clear reference to 450 ppm CO2eq limit. Any information about this fact ? In the Stern report, CO2eq includes of course all GHGs (see chapter 8).
  20. Greenhouse Gas Concentrations Continue Climbing
    OPatrick @28. Indeed. Measurement is usually taken from pre-industrial times ie 1750. Forcing from the LLGHGs by that measure stood at 2.8 W/m^2 in 2010 which is a rise of 29% over the previous 20 years. The WMO bulletin linked in the first paragraph of this story is not long (4 pages inc pictures & info boxes) and quite readable.
  21. The Debunking Handbook: now freely available for download
    skept.fr: #13: "an unbalanced 'over-criticizing' of some works they unduly exploit (Schmittner is not Spencer!). " I'm sorry, but I cannot determine what you mean by this phrase. #15: "Tamino is not a climate scientist. If you don't scotch to this editorial rule, why not consider the McIntyre's" Another false equivalence. If you are suggesting that 'all climate blogs are created equal,' you are severely mistaken. If you think that tamino = McIntyre, why not tamino = WUWT? Why not use authoritative sources whose work stands up to inspection? Why equate said sources with those whose work fails inspection?
  22. Of Averages and Anomalies - Part 1B. How the Surface Temperature records are built
    The description of the reference station method in this blog post is a little different than the original description by Hansen and Lebedeff. The blog post writes: "The average for each pair of stations (T1, T2), (T1, T3), etc. is calculated over the common reference period using the data series for each station T1(t), T2(t), etc., where "t" is the time of the temperature reading" Below figure 5 in the article (inserted in the blog post) the description is: The value dT is computed from the averages of Tl(t) and T2(t) over the common years of record" The wording in the blog post suggests (at least to me) that dT is estimated only over the reference period, which for GISTEMP is 1951-1980. While the article emphasizes that dT is estimated using all data in the overlapping periods.
  23. The Debunking Handbook: now freely available for download
    skept.fr @15, although Tamino is a mathematician rather than a climate scientist, he has published in the peer reviewed literature on climate science. I believe he currently has another article soon to be published that arose from discussions on his blog. So your claim that "Furthermore, Tamino is not a climate scientist." while technically correct is not relevant. Further, comparison of Tamino's site to McIntyre's as an uncalled for insult to Tamino. McIntyre has been repeatedly shown to not be lead by evidence. His posts typically obscure relevant facts, rather than lay them bare (IMO). Further, your council in this case makes the perfect the enemy of the good. Like it or not, denier misrepresentations are often so fundamentally flawed that you will not find peer reviewed literature discussing the relevant facts, and or debunking argument. Claims by one prominent Australian denier that CO2 actually cools the Earth's surface relative to what it would be with no greenhouse gases in the atmosphere fall under this category. In other instances, flaws in denier papers are picked out and highlighted long before any peer reviewed literature will discuss them, simply because of the slow turn around time on peer reviewed literature. In both cases, clear and compelling discussion of the issues can be found on several blogs. The suggestion that SkS should either discuss the issues without reference to those other discussions (thereby pretending that while other blog discussions are suspect because they are blog discussions) or not discuss them at all because we do not have peer reviewed literature addressing the issue are both unwise. The simple fact is that Tamino, or RC, or Science of Doom will often have clear and accurate analysis on particular issues that are (in many instances) better than we can produce ourselves. In that instance, we serve our readers best by drawing attention to those discussions.
  24. SkS Weekly Digest #26
    3 - KR "the confusion between the homonyms ... is something of an inside joke for English." and even that can be take too far http://www.youtube.com/watch?v=qu9MptWyCB8.
  25. Greenhouse Gas Concentrations Continue Climbing
    Ah yes, I see the IPCC definition of radiative forcing is relative to pre-industrial levels: "Radiative forcing is a measure of the influence a factor has in altering the balance of incoming and outgoing energy in the Earth-atmosphere system and is an index of the importance of the factor as a potential climate change mechanism. In this report radiative forcing values are for changes relative to preindustrial conditions defined at 1750 and are expressed in watts per square meter (W/m2)." Is that the generally accepted usage?
  26. SkS Weekly Digest #26
    Alexandre - "To" is a function word, as in "Travel to the south", while "Too" refers to amounts, an excessive level, as in "Too much". The mispronunciation "stoopid", on the other hand, is a linguistic joke/accent indicating that the speaker is, indeed, not of peak intelligence. I would have to agree that this particular cartoon doesn't make too much sense to non-native speakers - the confusion between the homonyms "To, Too, Two" is something of an inside joke for English.
  27. SkS Weekly Digest #26
    1 - Alexander. I think 'to stupid' should be 'too stupid' but someone who says 'stoopid' sounds stupid.
  28. Greenhouse Gas Concentrations Continue Climbing
    OPatrick it's 29% from pre-industrial not from an atmosphere witout greenhouse effect.
  29. The Debunking Handbook: now freely available for download
    #14 Tom : well, it's hard to re-discuss Schmittner here because it becomes... off-topic! For Tamino, it seems that a) Schmittner et al used UVic model, an EMIC, different from CCCMa models, full AOGCM (if it is true, the reference to Tamino's critic of CCCMa is simply unfounded in the discussion) ; b) would the model be CCCMa and not UVic, I consider it is legitimate to analyse Schmittner 2011 from peer-reviewed works on the same subject (either LGM temperature/forcing or the quality of their model assessed by other modellers), but not to refer blogs. That's a general rule for me, even the better blogs animated by climate scientists are just blogs, nothing more. And furthermore, Tamino is not a climate scientist. If you don't scotch to this editorial rule, why not consider the McIntyre's obscure and technical considerations on proxy series as a legitimate argument in a discusion of paleoclimate? In my sense, low criteria of rigor in the sources of our argument opens the door to confusion between real climate science and unchekced / approximative considerations – a confusion in which denialists are specialists! (In comments by laymen, as I am, it is unescapable to be imprecise and it may be useful to indicate blogs for animating the discussion, but I refer to main article from SkS, not their comments). Of course, I don't consider that SkS is in the same category that Joe Romm's website.
  30. What's Happening To Tuvalu Sea Level?
    Rob Painting "The long-term sea level trend at Tuvalu (over 1950-2009) is due to thermal expansion of the oceans, the addition of water volume to the global oceans by melting land ice....." That could be said of any averaged point on planet Earth's oceans, and is an essential piece of evidence for global warming. Forgive me if I am a bit obtuse, but I don't see the point in focussing on Tuvalu as an example. Local variations on tiny dots in the Pacific would be irrelevant I would think. There is a danger that skeptics will take such emphasis on places like Tuvalu as alarmism by the global warming fraternity, which diminishes the general point about evidence of global sea level rise.
  31. SkS Weekly Digest #26
    Could anyone explain the "two O's" line to a non-native English speaker, please?
  32. Economic Growth and Climate Change Part 1 - Factors Influencing CO2 Emissions
    #26, #44 Concerning demographic transition, there is a negative correlation of total fertility rate with human development index... up to a certain threshold after what it seems to reverse ( Myrskyla et al 2009 ). Female education / autonomy (part of the HDI) is considered as one the multiple factors for this transition. But more detailed analysis are certainly welcome. For example, this gender-based paper from Maria E. Cosio-Zavala examines some local trajectories to understand what kind of men-women relationships (and cultural representations of women's authority) could influence the fertility rate.
  33. SkS public talks in Canada and AGU, San Francisco
    So close, yet so far -- I hope to see an East-Coast trip at some point :-D
  34. Greenhouse Gas Concentrations Continue Climbing
    Riccardo, the 9C comes from 29% of the 33C of temperature ususally assigned to greenhouse gases. I know that we wouldn't be expecting 9c of warming, but at a superficial reading I that is what is implied by "there was a 29% increase in radiative forcing - the warming effect on our climate system - from greenhouse gases". I think I understand your explanation, though I'm not sure, but I definitely don't think it's clear from the WMO report.
  35. The Debunking Handbook: now freely available for download
    skept.fr @13, I believe you are being too harsh regarding actually thoughtfull's comment. If we are going to make a careful analysis of a paper, as dana did with Schmittner et al, we should not only identify potential problems identified by the author, but also other reasonable grounds for critique. We cannot rely on a scholarly response for that, for no published critique of Schmittner et al is available. Therefore it is quite appropriate to draw on rigorous critiques from the better blogs, of which Tamino's Open Mind is one of the best. With regard to your response to muoncounter, I do not think SkS is guilty of unbalanced "over-criticizing" of some works. It you want to see an unbalanced over-criticizing, compare Dana's post on Schmittner et al to that by Joe Romm, who calls Schmittner et al "a new deeply flawed study". That is, of course, a load of nonsense. I am not aware of any flaws in Schmittner et al. They applied a valid technique to the best proxy set of LGM temperatures they could find. To the extent that they are wrong about climate sensitivity, it will be because the best proxy set is neither accurate nor extensive enough, and because due to computational limitations they used only one mid-level climate model. Both limitations are not flaws but simply the constraints of real science, which must work with the data available, and within a budget.
  36. Greenhouse Gas Concentrations Continue Climbing
    OPatrick I don't know where your 9 °C comes from. A 29% increase in forcing from 1990 to 2010 means that the equilibrium temperature anomaly would be 29% higher. If we take, for example, the equilibrium anomaly relative to 1990 forcing as 1 °C, the one relative to 2010 forcing would be 1.29 °C.
  37. Schmittner et al. (2011) on Climate Sensitivity - the Good, the Bad, and the Ugly
    Pauls @15, thankyou for the link to Sutton et al. The key claim is that:
    "These experiments are in equilibrium, and yet the warming ratio remains significantly above unity for all the available models (range 1.18 – 1.58; mean 1.33; standard deviation 0.13.)."
    I note that the highest value is an outlier, with the next highest values being approx. 1.46. Indeed 5 out of 9 models group in the range of 1.18-1.3. This suggests to me that the high values are aberrant, and that refinements of the warming ratio will probably reduce the mean by reducing the top end of the range. Regardless, I must base my beliefs on the evidence before me, not on how I expect the evidence to develop in future. On that basis I have under estimated the equilibrium difference between land and ocean temperatures. That being said, Schmittner et al show a warming ratio 1.76 (if adjusted for sea level) or 1.65 (if not adjusted). Both values lie considerably outside the range we would expect based on Sutton et al. Therefore, although the difference between sensitivity estimates based on land, or ocean data only does not need as much explanation as I thought @1 above, it still indicates problems with the overall sensitivity estimate.
  38. The Debunking Handbook: now freely available for download
    #12 Tom: OK, this is a good point, like #6 and #7 but more clear. I totally agree that the cherry-picking one particular sensitivity is a misinformation for public, because it misrepresents climate science diversity of results on this question. (IPCC AR4 best estimate is rather 3,2 K for doubling, but a detail). #11 actually thought: yes but it seems to me there was some particular efforts to go beyond the author reservation (typically, to refer a tamino non peer reviewed critic suggesting the model is incorrect: climate science is not done on blogs! Even if I appreciate and read tamino). I myself suggest in commentaries some critics that went to be wrong, see for example Dr Schmittner's recent precisions about the proxies data (better than Shakun 2010). #10 muoncounter : of course denialists are trumpeting politically-biased and fanciful 'victories' on 'mainstream conspiracy'. My worry is that the counter-argument of denialists' myths translate in an unbalanced 'over-criticizing' of some works they unduly exploit (Schmittner is not Spencer!).
  39. Economic Growth and Climate Change Part 1 - Factors Influencing CO2 Emissions
    adelady @26 Last week I made this very point to a group whose arguments on population were degenerating along racist lines. I was the only male arguing that education and womens rights were the key to population control, a surreal experience! This was broadly encompassed under the term 'family planning and cultural changes' in the text. Perhaps it would have been best to mention female education and rights more explicitly! Sir David Attenborough recently covered these issues in the documentary 'How Many People can Live on Planet Earth' http://topdocumentaryfilms.com/how-many-people-can-live-on-planet-earth/
  40. Greenhouse Gas Concentrations Continue Climbing
    Moderator Response: [DB] CO2 increases do not cause linear increases in temperatures. Yes, but my naive understanding was that *radiative forcing* does cause linear increases in temperature (e.g. from AR4 "Radiative forcing can be related through a linear relationship to the global mean equilibrium temperature change at the surface" http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch2s2-2.html) I thought the nonlinearity part was between CO2 increase and resulting radiative forcing.
  41. Schmittner et al. (2011) on Climate Sensitivity - the Good, the Bad, and the Ugly
    As a layman it is very hard to comprehend the plausibility of the Schmittner et al paper using the paleo record as an indicator of the planet's sensitivity to a doubling of CO2 without more clarity on just what factors are excluded from their analysis. Such factors might include: 1/- Disparities in the initial conditions due to other impacts, including: planetary tree cover - of which about a third has been lost in the last few centuries; and oceanic plankton stocks - of which perhaps 40% have been lost in the last century, and soil fertility - of which a substantial fraction has been lost in recent millenia, and the presence of rather large holes in the ozone layer over both poles; etc. 2/- The influence of the pace of initial CO2 release and its warming on the consequent additional warming from the several major carbon banks' destabilization - both in terms of changes in the rate of output and of the ratio of CO2 to CH4 released, and of the short residence period of airborne methane being extended wherever its concentration became sufficient to swamp other elements required for its normal reaction rate. 3/- The presence of substantial airborne volumes of additional GHGs, including anthro-methane, anthro-Nitrogen Oxide and fluro-carbons this early in the curve of warming that must affect the rate of warming, thus exacerbating item 2/- above. A further point of obscurity is the rationale for describing the positive feedbacks in just two classes, "fast and slow." This appears both to overlook the relevance of potential scale (allowing potentially large acceleration) and to oversimplify pace. If they were instead described respectively as "large, medium or small," and "fast, moderate or slow" then nine distinct classes of feedback would need to be assessed for their potential influence, along with some feedbacks' transitions from one class to another. This would be less arbitrary but is surely more problematic than simply assessing their potentials individually and iteratively ? In sum, I'd ask whether it is possible to use the paleo record to propose a scientifically credible figure for the extent of warming at equilibrium with a doubled airborne CO2 - without first identifying the consequences of the rate of the warming our society imposes ? Plainly, as dana makes clear, Schmittner et al's analysis is not comparing apples and apples, but to what extent do they attempt to compare bananas and next Wednesday ? Regards, Lewis
  42. Climategate 2.0: Denialists Serve Up Two-Year-Old Turkey
    #93 Scaddenp, I read that post and (-snip-)
    Response:

    [DB] Please put your reply to that post on that post.  Not here, where it is OT (OT portion snipped).

  43. Greenhouse Gas Concentrations Continue Climbing
    (Not any more!)
  44. Greenhouse Gas Concentrations Continue Climbing
    "Between 1990 and 2010, according to the report, there was a 29% increase in radiative forcing - the warming effect on our climate system - from greenhouse gases." Could someone contextualise this - a naive interpretation could be that there should have been a 29% increase in temperature due to greenhouse gases, or about 9C of warming. (I'm also getting reduced font size.)
    Moderator Response: [DB] CO2 increases do not cause linear increases in temperatures.  The accepted sensitivity of the climate is about 3 degrees C per doubling of CO2 concentrations.  And there is about a 40-year delay in temperature response of the climate due to the thermal inertia of the oceans. 

    Thus, the temperature rise we see today is largely attributable to the CO2 emissions from the 1970s.

  45. Schmittner et al. (2011) on Climate Sensitivity - the Good, the Bad, and the Ugly
    Thanks for your comments, Dr. Schmittner. We went back and forth a few times trying to figure out which would be the correct temperature to use for an apples-to-apples comparison. It's possible we chose the wrong value, but as you note, it's difficult to ascertain whether the 5°C value refers to SAT only, or air and ocean surface combined.
  46. Greenhouse Gas Concentrations Continue Climbing
    Yep, subscript fix worked... (a few versions behind on Firefox here at work, hence the discrepancy).
  47. Greenhouse Gas Concentrations Continue Climbing
    Getting the font issue here as well, on Firefox. Looks to me like the subscript at the end of comment 4 wasn't closed (i.e. the subscripted 2 in CO2).
    Moderator Response: [DB] That was it; congrats (no prize tho).  Still looks the same on my screen (Firefox 8.0).
  48. AndreasSchmittner at 16:06 PM on 28 November 2011
    Schmittner et al. (2011) on Climate Sensitivity - the Good, the Bad, and the Ugly
    Sorry, your -2.6 K quote was, in fact, correct. But you didn't specify what it means. This number refers to the SST change over the ocean and SAT over land. Note that it is different from the global mean SAT change of -3 K. I don't know what Hansen and Sato refer to because they just talk about temperature change. The distinction between sea surface temperatures and surface air temperatures is important if you want to avoid comparing apples with oranges. Andreas Schmittner
  49. AndreasSchmittner at 15:46 PM on 28 November 2011
    Schmittner et al. (2011) on Climate Sensitivity - the Good, the Bad, and the Ugly
    The Hansen and Sato (2011) paper refers to the dataset from Shakun & Carlson (2010) for the 5 deg C LGM SAT cooling. This dataset is a subset of our LGM temperature reconstruction. Please note that our dataset includes much more data (435 grid points) than the Shakun & Carlson dataset (~54 grid points). It remains to be seen if there are inconsistencies between the different datasets. This will be an important task to study in the future. But for now I would claim that because we use a much more extensive dataset our LGM cooling estimate is more reliable than the one used by Hansen and Sato. Your quoting incorrectly that our global mean cooling for the LGM is -2.6 K. Also I recommend to specify what exactly you mean by cooling. The -2.2 K number you quote from our paper is the global mean of SSTs over the ocean and SAT over land. This number is dominated by the ocean because (a) there's more data and (b) the land grid boxes are 2x2 degrees and the ocean boxes are 5x5 degrees. (Note that this is not our choice, but we adopted it from the MARGO and Bartlein papers). This leads to the surface area covered by land points to be only 1/10 of that covered by ocean points. Therefore the area weighted global mean is very close to the ocean global mean of -1.9 K. Our best estimate for the global mean surface air temperature change is -3.0 K. Andreas Schmittner
  50. Greenhouse Gas Concentrations Continue Climbing
    @mods - something's happened to the formatting around the start of comment 5 - the font size is smaller from then on. Also affects the 'recent comments 'page'. And a brief correction to the first sentence that introduces the post - it's World Meteorological Organization, not Association. Will have to let the Americanised spelling slide as the WMO go for that!
    Moderator Response: [DB] Sky, the fonts look OK on my screen (both locations). Will fix the other bit, thanks.

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