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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 67651 to 67700:

  1. Medieval project gone wrong
    Thanks CB! #41. Makes perfect sense with the pair of maps (MWP and today compared with baseline temps of 1960-1990) and the difference is dramatic! Still wondering about the source (hence accuracy) of the MWP data (ie, Tropical Pacific? Central Asia?, North America? ), and still wondering what could cause such a 'roving' temperature aberration.
  2. A thoughtful conservative perspective on climate
    I have to disagree with the moderators. Because American politics is so polarised due to fear of the media and big corporations, then writing an article about a conservative politicians views about climate science makes the article political. But the problem isn't with the article, the problem is with American politics and that is why the article is justified. Statistically there should be more American conservatives that agree with AGW, the fact that there isn't suggests that more than just facts are distorting the stats.
  3. UAH Misrepresentation Anniversary, Part 1 - Overconfidence
    victull, I agree very much with Tom's summary above. I also don't have a problem with Dessler's statement. As Tom says the measurement of tropospheric temperature trends using satellite MSU (or weather balloons) is difficult, and there are subjective choices to be made in merging satellite records, correcting for extraneous contributions to apparent temperature etc. It's perfectly acceptable to be skeptical of these measures. They are useful though. Largely (but not exclusively) through the efforts of the RSS team we can conclude that apparent tropospheric warming is so far not inconsistent with expectations from physical understanding of the earth response to radiative forcing. That's a very important conclusion, and unfortunately one that Christy/Spencer seem determined to misrepresent. In fact scientists generally love finding apparent incompatibilities between predicted and observational phenomena (in this case between apparent tropospheric temperatures and physics-based expectations); we know there's science to be done and discoveries to be made in resolving these. Most scientists use them productively to focus efforts that advance our knowledge/methodologies; very few use them as S/C to pursue non-scientific aims. This is apparent by looking at the published work of the UAH and RSS teams. The RSS work simply inspires confidence that bright minds are focussing on resolving the issues productively. That doesn't mean that the RSS data is necessarily "correct". But their analyses are supported by scientifically justifiable choices, with careful consideration of errors and so on. That hasn't happened with the UAH duo who have continued a 20-year assertion that their (ever-changing) analyses are correct and demonstrate a fundamental incompatibility with physical understanding. They have shown little interest in addressing the apparent inconsistencies which turn out to a very large part to be due to errors in the very analyses they have asserted to be "precise". As for Dessler, it would be interesting to know the context in which he said the statement you copied. (One of) Dessler's expertises is in analysis of tropospheric water vapour and how this responds to greenhouse forcing to provide climate feedbacks. We know that tropospheric water vapour has increased (itself an independent confirmation of a warming tropsophere), and while the water vapour feedback largely arises from changes in water vapour in the upper troposphere, Dessler's work would be made a whole lot easier if the vertical structure of tropospheric temperature, and its response to greenhouse forcing, was known more accurately. Then the relationship between absolute and relative humidity, and the strength of the water vapour feedback, etc., could be determined rather more accurately. So I expect Dessler's statement may be related to a frustration with the continuing uncertainty in these measures in that they directly impinge on his work. In Dessler's papers I've read that address water vapour feedbacks in response to surface warming he doesn't use satellite MSU temperature data...
  4. littlerobbergirl at 22:57 PM on 29 December 2011
    A thoughtful conservative perspective on climate
    CBD - i know a few other 'exceptions to the rule', not 'neocons' but hard core free market conservatives. one is actually taking his company into renewable energy where he sees a big business opportunity. nice subversive use of the 'al gore' dog whistle in the excerpt; talking to them in their own language!
  5. Medieval project gone wrong
    markx, the answers to your questions and more information about the map can be found in the article it came from; MWP article
  6. A thoughtful conservative perspective on climate
    A neo-conservative who accepts basic scientific facts and makes rational suggestions? Suddenly I think I understand how AGW deniers must feel when confronted with proof that their understanding of 'reality' is flawed in some way. I've gotten too used to these people being 'wrong' about everything... science, economics, foreign policy, social issues (though those are more in the realm of opinion). The last time I really agreed with something they did was when W Bush spoke out against anti-muslim bigotry in the US... and I couldn't believe he was on the right side of that either. That said, I think I'm on solid ground saying this guy is the exception rather than the rule. The idea that rational scientific discussion about AGW, evolution, anything environmentally related, et cetera could flourish in any major branch of US 'conservatism' (as much a misnomer as 'skeptics' IMO) seems more than far-fetched.
  7. Medieval project gone wrong
    Thanks Tom #37. I'm not quite sure what the map is showing? It is titled "Temperature Pattern for the Medieval Warm Period" but you state underneath "...represents the global average increase in temperature from the 1960-1990 baseline to current temperatures...." I gather this map/chart is a three century mean of the MWP 'time'? The rise is then compared with which period? Given the doubts on the data we do have for that period, is all this information really available? (Sorry for all the questions, and I made some assumptions to keep the questioning to one post). Thanks Rob #30. Nothing being argued at all. Just commenting on perhaps the very reason the main topic of the article is of such interest to many, and why it will probably become more so as more such reports come out.
  8. UAH Misrepresentation Anniversary, Part 1 - Overconfidence
    jmorpuss @17, the book is a university level text book on remote sensing using microwaves that does not deal explicitly with temperature sensing directly. Specifically, the Microwave Sensing Unit and the Advanced Microwave Sensing Unit are not discussed even when missions with those instruments where discussed. The author is a member of the Russian Academy of Sciences, and the book appears to be well respected. Consequently it would be a very useful resource for anybody seeking detailed background knowledge to understand issues that effect detection of air temperatures using satellites, especially if they are familiar with calculus. (It would be heavy going if you are not.) Clearly, therefore, it is a relevant resource for the topic of the main post. What is not on topic here is your usual rambling expositions of your crackpot theory of global warming based on physics that you clearly do not understand.
  9. UAH Misrepresentation Anniversary, Part 1 - Overconfidence
    Tom Curtis Do you think this book on remote sensing is worth reading or is it not welcome hear. It's explains alot of interesting things regarding the electromagnetic processes and interactions http://www.iki.rssi.ru/asp/pub_sha1/pub_sha1.htm
  10. A thoughtful conservative perspective on climate
    Pertinax's distraction actually summed up the response problem perfectly. Stupidity is intimidated by the nature and foundation of the problem. They don't 'get it', but they do understand 'lefties', 'the menace of socialism', and 'ivory tower parasites'. This is 'their time'. If anyone knows a way to demonstrate to them the consequences of their stupidity policies, yesterday would be an excellent time to lay it out.
  11. A thoughtful conservative perspective on climate
    Jimspy, I think those promoting promoting policies that fly in the face of both the scientific and economic majorities are practicing deception, plain and simple. Hence: Decepticon.
  12. A thoughtful conservative perspective on climate
    It's been moved and seconded that a new way be found to distinguish neo-cons or other intellectually honest conservatives from those who deny science. Apparently the word "agnatology" means "anti-science." I propose that a new term such as "agna-con" or some such commingling of "agnatology" and "conservative" be coined to make this distinction. Less frivolously, I think some way should be found to place a premium on robust dialog with the realistic brand of conservatives - inviting them to the table, relishing the conversation, agreeing to disagree politely where appropriate, and generally making it clear that such discourse is the order of the day. In other words, MARGINALIZE the agna-cons and send the message that, until they've "read the memo" and signed on to the idea that Yes, Virginia, There IS Global Warming, they are the skunks at the garden party.
  13. A thoughtful conservative perspective on climate
    It is an election year. The Democrats will use anything including climate change to pursue their political aims and the Republicans will oppose what ever they say. It is far easier for conservatives to just deny AGW than to try and fight all the increasing spending, taxing regulations and subsidies to Democrat causes that will be proposed in its name. So they will do it. { - off topic political statements snipped -}
    Moderator Response: [muoncounter] Please restrict your comments to the topic of the post. This is not about politics; it is about a conservative response to climate change science.
  14. UAH Misrepresentation Anniversary, Part 1 - Overconfidence
    victull @14, I would support Dessler's claim. The simple fact is that measuring tropospheric temperatures by satellite is very complex. This is made more difficult because more recent instruments use a slightly different frequency than did earlier instruments, and hence weight different altitudes differently. In addition to complexities involved in correlating measurements from different instruments on different satellites, you must compensate for orbital drift, diurnal drift and changing altitude. You must do so over a great range of atmospheric conditions, with corrections over the tropics not necessarily appropriate in the sub-arctic due to different altitudes of the tropopause and humidity levels. On top of that you are relying on instruments that sample a significant proportion of the stratosphere (which has an opposite temperature trend to the troposphere) and which have different weights for low altitudes over ocean and over land due to the different reflectivity of land and water to microwaves. These difficulties all apply to the TMT channel which is based on a single instrument (in each satellite). The TLT temperature series is derived from the TMT channel by various ad hoc adjustments, based on either the difference between data from vertical and lateral views (UAH), on microwave radiation models (RSS). It is no wonder then, that the four teams measuring TMT (channel 2) trends obtain four different results. (Note, by my reading V&G measure the trend of Channel 2, ie, TMT; not TLT as shown in table 1 above. Further, Fu et al measure a hybrid channel of their own devising which does not strictly correspond to either TMT or TLT.) Nor is it any surprise that the two teams measuring TLT trends also come up with different results. This situation represents a stark contrast to the measurement of surface trends. The different methodological choices of the various measurements of surface trends are known,and can be easily compensated for. When that is done so that we have apples to apples comparisons, the resulting trends are almost identical, and well within error. Therefore we can be very confident that the surface trend is very close to that obtained by GIStemp. (Not HadCRU as it does not have global coverage.) With satellites, however, we know UAH is under estimating the trend with a high degree of confidence. However, we do not know that RSS is correct, or that it itself does not also underestimate the trend.
  15. UAH Misrepresentation Anniversary, Part 1 - Overconfidence
    Good stuff (but feel free to delete after seen) Minor suggestions: in the tables, can you get the decimal points to line up? That helps, visually. Alternatively, albeit at hint of unwarranted precision, make them all 3 decimals. Also, you might want to link to: http://tamino.wordpress.com/2011/12/06/the-real-global-warming-signal/
  16. UAH Misrepresentation Anniversary, Part 1 - Overconfidence
    Chris & Tom Thanks for the detailed information. In summary, Spencer and Christy have made errors in the UAH analysis which they subsequently corrected but not as much as other scientists in the field identified (ie RSS analysing the same data). Spencer and Christy then distorted their results in statements which were inaccurate and tended to mislead. Well clearly Spencer and Christy are not babes in the woods and therefore some intent is evident. In rightly criticizing Spencer & Christy, I fail to see why Dessler's statement was used. Dessler cast doubt on the value of satellite atmospheric temperature measurements in general (including RSS) which I expect dana, Tom and Chris would not support.
  17. A thoughtful conservative perspective on climate
    Tom: though I consider myself a conservative (I grew up in tar sand land, Alberta), I'm not an expert on conservative thought. Wikipedia is probably better. Having spent a lot of time reading Antiwar.com (libertarian site) in the run-up and prosecution of the Iraq War, I think it's fair to say that a significant fraction of conservatives hate neocons. I think most conservatives are distrustful of big government projects; they are wary of spending money in far away places outside the oversight of their democracy. War is a big government project of the sort that should challenge conservative values, yet neocons support it enthusiastically. Other international interventionism (climate treaty emission targets, trading schemes, and foreign offsets) will I think find more resistance among typically isolationist conservatives than among neocons (who seem to weigh international opportunities and risks differently). Engagement of paleocons in addressing AGW is likely further away, and possibly on a different road, than engagement of neocons. That's my oversimple opinion, if it's of any help.
  18. A thoughtful conservative perspective on climate
    @4 John H. -- Good point re: many Republicans. It's worth another post. @7 VoxRat re: Inglis. Inglis did not lose "because he acknowledged the reality of AGW," at least according to those closest to the race. According to Bob Jones U poli Sci prof Linda Abrams, "it was a sequence of things'...over four years." Which of his many breaks with conservative orthodoxy cost him the most? The article concludes: "The answer may well be "D, all of the above," plus a general sense that he wasn't reflecting voters' mood along with the option of a credible candidate that hadn't appeared before, Abrams said."
  19. A thoughtful conservative perspective on climate
    @9 Steve L & @10 Thanks for catching the bad link. It's now repaired. :) BW, in addition to Tobin's challenge, be sure to check out Wehner's excellent response, both linked at this follow-up post to the one above: A thoughtful conservative -- challenged @3 Steve L Good point about not lumping all neo-cons, conservatives and Republicans together. What would you suggest as a more accurate way to characterize Wehner and neo-cons vis-a-vis conservatives?
  20. A thoughtful conservative perspective on climate
    JohnH: Ironic though, that Nixon established the EPA and passed the Clean Air Act; his ideological descendants would eliminate both (among other things - like funding for NOAA and NWS).
  21. Renewable energy is too expensive
    Also of interest, this IPCC SRREN 2011 figure : range in recent levelized cost of energy for selected commercially available RE technologies in comparison to recent non-renewable energy costs. It must be precised that this is the cost for producing electricity (or heat, or fuel) from RE local units, but a global energy transition will require additional costs : to transform the infrastructure of distribution (grid) and to electrify many final uses (for example public transport). That's why this transition must begin now and be as progressive as possible. As your article put it, the true cost of fossil sources is underestimated because externalities (climatic and non-climatic) are ignored by market. A pigovian tax on carbon would restore intergenerational equity and real price of carbon. Many economists agree on that point and it is unfortunate that policymakers delay their decision. All the more so that the actual dependency to fossil ressources threatens economy in case of high volatility. Climate-energy policy should be rational, cooperative and bipartisan.
  22. A thoughtful conservative perspective on climate
    @9 Steve L, no it's a bad link. It should be http://www.commentarymagazine.com/2011/12/23/climate-change-conservatives/
  23. Medieval project gone wrong
    Something interesting I just now noticed. If you compare that CO2Science interactive map with the IPCC MWP map that Tom just posted... it looks very much like the Idso's cherry picked their way around the large areas of cooler MWP. I haven't done a detailed look into it but it sure looks like the skip over most of the Baltic region and into Siberia. They skip that swath across central Africa. They skip western Canada and the north slope of Alaska. The IPCC map makes it look like there IS data for those regions that the Idso's are not showing.
  24. A thoughtful conservative perspective on climate
    Am I the only one who gets a weird 403 Forbidden when clicking on the link to Tobin's 'Environmentalist Hysteria' article?
  25. A thoughtful conservative perspective on climate
    I don't know whether to be encouraged or dismayed. I am actually counting on the continued denial of conservatives coupled with the increasingly undeniable evidence of the truth to eventually break the backs of the conservatives. And case in point of the inability of people to separate "is it happening?" from "what should we do?": The editor argues against an article saying that warming is happening by saying but warming may be good.
  26. A thoughtful conservative perspective on climate
    Congressman Bob Inglis (with impeccable conservative credentials) lost his bid for re-election, apparently because he acknowledged the reality of anthropogenic global warming. National Public Radio has an interview with him here: http://www.npr.org/2011/12/24/144231819/ousted-by-tea-party-rep-inglis-looks-back
  27. A thoughtful conservative perspective on climate
    There will always be a sizable group of those that are "skeptical" for whatever reason. But, I'm more hopeful that empirical reality will eventually trump political expediency, and that conservatives and republicans as a whole will begin to see the societal and political costs of holding positions that ignore empirical reality. I'm just not sure of the time frame - and there is the rub.
  28. Foster and Rahmstorf Measure the Global Warming Signal
    #90 Albatross : of course we can agree on your last point. (But very frankly, such careful analysis of press releases is not my cup of tea, because press releases have no scientific value.) #88 Tom (sorry I miss your message when answering to others). a) Don't understand your point. Long term solar influence (in the sense of #89) is not particularly related to the 11 yr cycle variation, but to multicycle trend (if any). And spectral change may be more complex than we thought, there is a current debate (for example SIM-SORCE and VIRGO-SOHO do not find the same UV versus total variation in recent cycle 23). b) Point already discussed, but not relevant for the question (precision of GHG attribution) as a removal of ENSO (from MEI data) cannot be seriously described as a "precise" analysis of forced and unforced multidecadal variability. c) Spencer's vague assertions on his blog are not mine. (As I said to Albatross, afterthoughts of UAH team are not exactly an intellectual challenge IMO!) I don't know for Christy, but I recall that Spencer have written on his blog he believes GW comes fron "Mother Nature". I think this is a false belief, and I observe that when Spencer tried with Braswell to advance more scientific arguments, he was contradicted by Dressler. Sufficient to build my (provisional) opinion about the importance of his Mother Nature hypothesis, when compared to dozens of convergent articles on observation, detection or attribution.
  29. A thoughtful conservative perspective on climate
    Man, great effort but convincing science skeptics (many times all sort of science) is a steep uphill battle. The science is getting more solid by the day, but the problem is that it will require sth. spectacular to happen.
  30. A thoughtful conservative perspective on climate
    Contrary to popular opinion, not all of the members of the Republican Party are anti-environment and anti-AGW. You can see for yourself by checking out the website of the Republicans for Environmental Protection (RFP). In fact, a link to SkS’s own, “The Scientific Guide to Global Warming Skepticism” is prominently displayed on the front page of the RFP’s website.
  31. Foster and Rahmstorf Measure the Global Warming Signal
    skept.fr @89, "Please, recall the precise background. The very last part of the discussion here is related to the SkS paper on Christy and UAH." Please note that I am, of course, very well aware of the background and context.Please note too the objective of the post; specifically note too that it is not meant to be an overview of attribution papers. Dana merely cited two recent examples of papers in the literature that challenge Spencer's ridiculous (and unsubstantiated) assertion/rhetoric. I agree with you that of the two papers, HK11 is the attribution study. But again, it is a moot point, because neither FR11 nor SkS claimed that RF11 was an attribution paper. We also seem to be in agreement that Spencer and Christy are (probably) knowingly engaging in rhetoric and making unsubstantiated and misleading claims-- those are the key issues. I hope we can agree that that is very troubling and not at all consistent with the actions of reputable scientists. No?
  32. UAH Misrepresentation Anniversary, Part 2 - Of Cherries and Volcanoes
    dana#30: "El Chichon pulled the temperature down below where it would have otherwise been (which is moving upwards due to the El Nino)." Agreed. If you download the data from FR2011 and graph UAH/RSS and the three externals (MEI, AOD and TSI; each lagged appropriately), that picture is clear. Without el Chicon, the el Nino warming of 1983 would have been much larger. That's only a 'cooling effect' in the strictest sense of the word - and that could mislead a reader to conclude that the apparent coolings on either side of 1983 were primarily due to the volcano. This further reinforces the fact that Christy's 'two volcanic eruptions tilted the trend' is incorrect: 1985's cooling is better described as the tail end of the volcanic aerosols coupled with a negative MEI.
  33. Foster and Rahmstorf Measure the Global Warming Signal
    #84 dana : "Given that TSI has not increased significantly for the past 60 years, unless there is a 60+ year lag effect" Solar forcing is still in "low level of understanding" in IPCC terminology, and we cannot be sure that TSI is the correct metric for estimating all solar influences on climate. See this very complete review by Gray et al 2010 for all the mechanisms that are currently studied by solar or climate scientists. (I'm not such a scientist, so I ignore if muoncounter is correct when he says : "(UV) is a weak hypothesis at best".) For a more than 60 yrs lag, I see no real basis for excluding this hypothesis. Ocean time response takes decades to millenias – that's why GHGs will influence climate on very long term, even if we stop rapidly their emissions. I suppose the same is true for solar forcing, so any change in TSI (or relevant metric) from Maunder to present (for example) could have a weak but real influence on present climate. For me, it would give a bad impression of "settled science" to go beyond the IPCC conclusion and to state that we are virtually certain there is no residual influence (which would imply a "high level of understanding"). I underscore "residual" because the point we're discussing here is not the Sun as a major driver for 1979-2010 T trend (denialist fantasy), but the Sun as a possible cause of a (very small if any) part of the trend. For the aerosol point, OK, but of course the cause of change in surface temperature is not the same, as it implies SW radiation for aerosols and LW radiation for GHGs. You can perfectly have a 30 yrs warming trend with no change in GHGs, just because aerosols decrease in the period. #85 muoncounter : don't understand why you insist on such details, my initial point (in Christy discussion) was that "FR2011 is not an attribution study", and de facto, it is not. As I added : "AOGCMs simulations, which are in charge of such attribution, suggest the 0,16 K/dec signal FR2011 have separated from natural noise very likely emerges from GHG forcing", there is no matter for debate here. Your quote from IPCC is clear : there is no "demonstration" in FR2011 because it is a statistical paper on (some) noise and not a physical paper on the origin of the signal (the very definition of an attribution). And you miss other quotes in 9.1.2, for example : Both detection and attribution require knowledge of the internal climate variability on the time scales considered, usually decades or longer. The residual variability that remains in instrumental observations after the estimated effects of external forcing have been removed is sometimes used to estimate internal variability. However, these estimates are uncertain because the instrumental record is too short to give a well-constrained estimate of internal variability, and because of uncertainties in the forcings and the estimated responses. Thus, internal climate variability is usually estimated from long control simulations from coupled climate models. #86 Albatross : "What you state is exactly what is being done. Scientists and SkS are not pinning everything on FR11" Please, recall the precise background. The very last part of the discussion here is related to the SkS paper on Christy and UAH . In this paper, SkS relies mainly on FR2011 and HK2011 to contradict a point in press release. I suggested it is not the beter choice, because FR2011 will not answer to the Christy's point. (I also suggested Christy's point was pure rhetoric and probably choose to be so, that is formally exact but physically uninteresting).
  34. Foster and Rahmstorf Measure the Global Warming Signal
    skept.fr @83: a) As noted above, any solar effect correlated (including negatively correlated) with TSI would contribute to the TSI signal component as detected by purely statistical means. Ergo any solar effect not accounted for must not correlate with TSI, ie, it must not show an 11 year cycle. To my knowledge, no such solar mechanism has been proposed. b) As discussed elsewhere, because the temperature signal minus the influences of AOD, MEI and TSI is very close to linear, the sum of remaining forcings must also be very close to linear. As no major oceanic oscillation has been close to linear over the period 1979-2010, they are thereby shown to have a minor effect on global temperatures, if any. c) It is true that we do not know how much changes in tropospheric aerosols have influenced the temperature. However what we do know because of the near linear increase in temperature is that the net forcing of GHG plus aerosols has not varied greatly from a linear increase. (Due to thermal lag, "greatly" is here a very relative term.) I note that Spencer has said in his blog in defense of his press release that:
    "In my opinion, the supposed “fingerprint” evidence of human-caused warming continues to be one of the great pseudo-scientific frauds of the global warming debate. There is no way to distinguish warming caused by increasing carbon dioxide from warming caused by a more humid atmosphere responding to (say) naturally warming oceans responding to a slight decrease in maritime cloud cover..."
    This is frankly inconsistent with any attempt to interpret his claims in his press release as being "...about a precise quantification of GHGs signal ...". Spencer is making a very bold claim. More specifically, the precise context of the quote from Dana's article is as follows:
    "Christy and other UAHuntsville scientists have calculated the cooling effect caused by the eruptions of Mexico’s El Chichon volcano in 1982 and the Mt. Pinatubo volcano in the Philippines in 1991. When that cooling is subtracted, the long-term warming effect is reduced to 0.09 C (0.16° F) per decade, well below computer model estimates of how much global warming should have occurred. Although volcanoes are a natural force, eruptions powerful enough to affect global climate are rare and their timing is random. Since that timing has a significant impact on the long-term climate trend (almost as much as the cooling itself), it makes sense to take their chaotic effect out of the calculations so the underlying climate trend can be more reliably estimated. What it doesn’t do is tell scientists how much of the remaining warming is due to natural climate cycles (not including volcanoes) versus humanity’s carbon dioxide emissions enhancing Earth’s natural greenhouse effect. “That is the Holy Grail of climatology,” said Roy Spencer, a principal research scientist in the ESSC, a former NASA scientist and Christy’s partner in the satellite thermometer project for more than 20 years. “How much of that underlying trend is due to greenhouse gases? While many scientists believe it is almost entirely due to humans, that view cannot be proved scientifically.”
    Clearly Spencer is talking very much about the sort of natural climate cycles (ENSO, volcanoes, the solar cycle) that F&R2011 explicitly deal with. It is absurd to suggest that it is legitimate for Spencer to talk about the trend introduced by volcanoes, but to consider irrelevant a paper that explicitly shows that trend, and that it is cancelled by negative trends introduced by other "natural cycles". Finally, I have learnt from long experience debating both creationists and fake skeptics of global warming (not to mention few "911 troothers", a geocentrist or two, and a couple of Apollo fraudsters) that there is no such thing as "blameless". No matter how impeccably precise you are they will find a way to distort what you say as a means of attack. As they would find reason to blame even a saint, the goal is simply to be clear and to have integrity. Reasonable people will recognize both qualities and not be distracted by denier nitpicking. (And in this case it is nitpicking, though not by deniers.)
  35. Medieval project gone wrong
    Markx - "With all this media attention on alarming weather stories, you surely can scarcely be surprised if the first question is, “ Has this ever happened before?” You are confused. A warming Earth doesn't mean we will see only unprecedented weather events, but rather that they are likely to become much worse. You appear to be arguing a strawman. Note that any further comments in this vein should be made on one of the extreme weather threads. It is off-topic here.
  36. A thoughtful conservative perspective on climate
    This is very nice -- good to see cracks where facts have a chance to squeeze into the 'conversation'. I would warn about the characterization of NeoCons here, however, because conservatives don't generally see the NeoCons this way. Most conservatives are more influenced by libertarian ideology. Many of these PaleoCons see NeoCons as opportunistic sell-outs who are more than willing to lie to achieve a hidden goal. It's still good to see these Commentary articles, but let's make sure they are characterized correctly.
  37. A thoughtful conservative perspective on climate
    For anyone who hasn't already seen it, Scott Denning's presentation at the ICCC (on youtube) is a direct appeal to conservatives who are stuggling to overcome thier cognitive biases and accept what the science is unequivocally telling us.
  38. Foster and Rahmstorf Measure the Global Warming Signal
    DaneelOlivaw @82, I have seen ENSO cited as the cause of the warming numerous times by deniers, and infamously, McLean, De Freitas and Carter have argued that ENSO is the major cause of the warming trend in the peer reviewed literature. Volcanoes cannot cause global warming, but their absence can. Notably both the strong warming in the early twentieth century and the Medieval Warm Period are attributed at least in part to a relative absence of large volcanic eruptions. Indeed, F&R2011 find that the lack of large eruptions since 1995 has contributed positively to the trend on all indices, although the net contribution is small and overwhelmed by other factors. Finally, TSI is declining but warming has been attributed to other solar related factors. Because F&R2011 use a statistical approach rather than a physical (model based) approach, any solar effects in addition to variations in TSI are also captured by their approach, so long as those effects are significantly correlated with the solar cycle. Therefore they rebut any putative increasing non-TSI solar forcing (so long as it is correlated with TSI) as well as TSI forcing as a cause of the long term trend. You state that:
    "In my view what they tried to do is to, knowing that global warming is primarily anthropogenic, remove the noise produced by other factors in order to see that anthropogenic signal more clearly."
    That is my view as well. However, that does not preclude their paper from having larger implications. One such implication is that, by identifying the temperature signal associated with each "forcing" signal, ie, the MEI, AOD, and TSI they reduce the uncertainty regarding the anthropogenic contribution to the rise in temperatures. A second is that by constructing a temperature signal free of identifiable noise, they produce a clear temperature signal which can be compared with putative causes of that signal. As indicated elsewhere, that comparison refutes most major alternatives to anthropogenic forcing as a cause of the temperature increase. Neither of these points is made in the paper - but they follow from it.
  39. Foster and Rahmstorf Measure the Global Warming Signal
    skept.fr @80 and KR @79, "So, you need a complex array of evidences – not just a paper grossly detrending for 3 factors on 3 decades or another running with an EMIC – to produce a correct assessment in detection-attribution. " Please, there is a whole body of science and literature out there on attribution. What you state is exactly what is being done. Scientists and SkS are not pinning everything on FR11-- with respect, you seem to be trying to argue a strawman. There is a compelling body of observational evidence out there that humans are causing the warming and and that includes research into estimating how much of that warming we are probably responsible for. RF11 is just part of a much bigger pyramid of knowledge. For the record, as far as I can determine, FR11 do not claim their paper is an attribution paper, nor does SkS.
  40. Foster and Rahmstorf Measure the Global Warming Signal
    DOlivaw#82: "one does not even need to apply much scrutiny at all to tell they are bunk." Unfortunately, we need to apply such scrutiny or the pseudos make it seem like they're going unanswered. Read the Pielke threads for a demonstration of that effect. But my question was rhetorical; a means to point out the failure of the pseudo skeptic to be skeptical of his or her own belief system (the belief in ABC - anything but CO2). skept.fr#83: "The better way to convince your reader is to be blameless." No, the better way is to be relentless in pointing out the failures of many, if not all, of the arguments positing ABC. Your point a. (UV) is a weak hypothesis at best. Your point b. (other oscillations) was shown to be moot in prior commentary. Your requirement of a model as a standard for attribution is novel, as it is not part of the definition of attribution in 9.1.2 quoted above. Do you read the word 'demonstration' to mean 'model'? Such models (showing GHG forcing as the dominant cause of the warming signal) exist; why do you require FR to reinvent this wheel?
  41. A thoughtful conservative perspective on climate
    For now, and at least the immediate future, it appears that accepting AGW theory results in losing all of one's conservative credentials in the US. AGW theory and this site were primarily responsbile for my own realignment. I suspect Mr. Wehner and others like him understand that any future political platform that denies AGW outright can't be sustained.
  42. Soares finds lack of correlation between CO2 and temperature
    Next up in our 'skeptic evidence' series: 'New study finds that Summer is warmer than Winter, and daytime warmer than night time... WITHOUT corresponding changes in CO2 levels!!! How will the enviro-commie AGW alarmists explain THAT!'
  43. Foster and Rahmstorf Measure the Global Warming Signal
    skept @83 - I disagree with a couple of your points. First, FR11 did quantify the climate response times to each exogeneous effect (it was 0-1 month for TSI). Given that TSI has not increased significantly for the past 60 years, unless there is a 60+ year lag effect - which I do no find physically plausible in the least, and none has been proposed - I don't think that's a valid concern with regards to the FR11 results. Second, the excluded aerosol effect is an anthropogenic one, and thus is part of the leftover (mainly) anthropogenic trend. The claim is not that the leftover trend is from GHGs, it's that it's anthropogenic. I have revised the text in UAH part 2 slightly to note that the remaining trend is *almost entirely* anthropogenic, as opposed to being totally anthropogenic, which may not be true.
  44. UAH Misrepresentation Anniversary, Part 2 - Of Cherries and Volcanoes
    Yes I think it's important to bear in mind that Christy is exclusively filtering out impacts from volcanic eruptions. It's true that those two volcanic eruptions produced a short-term cooling effect towards the first half of the record. It would be more accurate to say that El Chichon pulled the temperature down below where it would have otherwise been (which is moving upwards due to the El Nino). That's the problem with cherrypicking one short-term effect to filter out while ignoring other similar effects. It's a very poor analysis by Christy.
  45. Medieval project gone wrong
    markx @36, very briefly, you are still treating regional temperature proxies as though they where at least hemispheric proxies. Below is a reconstruction of the geographical distribution of MWP warmth: Orange on the map represents the global average increase in temperature from the 1960-1990 baseline to current temperatures. In the actual case, some areas of the globe have warmed more, and some less than that. It should also be noted that a three century mean is not strictly comparable to the decadal means we can compare current temperatures to. Never-the-less you can see that regional warmth is no indication of global or hemispheric warmth. In particular the unusual warmth of New Zealand and the Tibetan Plateau both show up on the map, but as isolated regions in otherwise cold areas. This map is not, of course, the end of the science on the MWP. But until the anthropogenic global warming skeptics start publishing reconstructions like this in the peer reviewed literature, their denial of the validity of these reconstructions rings hollow. The best currently available science shows the MWP was probably cooler than current temperatures. There are those who deny this, but they conspicuously are unwilling to produce any science to back up their denials.
  46. UAH Misrepresentation Anniversary, Part 2 - Of Cherries and Volcanoes
    muoncounter @28, I think your point is well made. However, rather than say there was not two volcanic coolings (there where) I would say that Christy is doubly inconsistent in ignoring ENSO effects as he needs to ignore ENSO effects to find his first cooling.
  47. Foster and Rahmstorf Measure the Global Warming Signal
    #81 muoncounter : Why is this level of scrutiny - and semantic precision - not applied to the pseudo-skeptics who routinely make unsupported claims? It is, and notably here on SkS. The better way to convince your reader is to be blameless. Concerning FR2011, here are some supplementary suggestions for understanding why it is not an attribution study: a) The solar forcing is reduced to TSI signal, but we know there are other factors influencing climate (for example spectral changes in UV, not correlated to total irradiance, and their effect on stratosphere-troposphere coupling). Furthermore, we don't know the precise time response of climate (mainly oceans) to solar forcing. So the T trend 1979-2011 may contain noise from past forcing from solar origin. Only a physical model can tell us. b) The unforced variability is ignored except for ENSO. See our long discussion above about all others modes of variability, and the possibility that coupling / decoupling of these modes create multidecadal variability, not just year-to-year change. Again, only a physical model can answer, see my reference to GEOMAR as an example of such model. c) the tropospheric aerosols (mainly from anthropogenic source) is ignored, so on the 32 yrs, we don't know what part of the signal is due to changes in aerosols inside the period and what part to changes in GHGs. Here too, a physical model would use estimation of aerosol emissions and fully calculate their direct/indirect effects so as to bring a clearer picture. The Christy point (other discussion) was about a precise quantification of GHGs signal - not about its existence, not even about its first order importance (even if Christy is skeptic about that, the press release is cautious). So the reference to FR2011 cannot answer to this level of precision.
  48. Medieval project gone wrong
    I appreciate the replies. (and I did read the original article: I hope you will forgive me or even commend me for not immediately accepting all I read. Hence the questions). Good points re Lamb 1995, thanks. The CET is discussed in Judith Curry’s page (a very interesting read, if somewhat rambling - that perhaps a function of apparently being collected as snippets over many months) http://judithcurry.com/2011/12/01/the-long-slow-thaw/ Re the MWP: Increased solar radiation and less volcanic activity are hypothesised as a likely cause of the MWP, but what is the explanation for the variations in the timing of this warming? It does seem strange. It is still interesting to me that these warming occurrences apparently did happen also in the southern hemisphere.
    MWP sensu lato in New Zealand adds an important new datum to the debate concerning its large-scale occurrence and supports Broecker’s [2001] argument that it was indeed global.
    SE bars on both the Tasmanian and New Zealand data both indicate the possibility of many ‘as high’ or higher temperature peaks over that recent 1000 year period
    ….it is apparent that the current warming trend over Tasmania is still a significant event when viewed in the context of multi-decadal variability covering the past 2000 years. In that period it remains the warmest event to a marginal degree, although a much longer warm period is indicated in the AD 900±1500 interval. The early 1900s period likewise remains a significant cold event, …………. little indication for a ``Little Ice Age'' period of unusual cold in the post-1500 period. Rather, the AD 1500±1900 period is mainly characterized by reduced multi-decadal variability.
    Indeed, the Tibetan data too shows several possible “much higher than normal” temperature peaks in “their” MWP of about 700 to 1100 AD. And I’m sure at least some of these would have made it onto the ‘extreme weather’ stories of recent times! With all this media attention on alarming weather stories, you surely can scarcely be surprised if the first question is, “ Has this ever happened before?”.
  49. UAH Misrepresentation Anniversary, Part 2 - Of Cherries and Volcanoes
    Tom C#25: There's a problem with the el Chicon eruption (1982): Because of the simultaneous eruption and El Niino, the climatic system felt the impacts of both, and it was difficult to separate their effects on temperature. Normally a large eruption like this would cool the global climate, especially in the summer, but during the first year after the El Chich´on eruption, no large cooling was observed, as the El Ni˜no produced large compensating warming. That's very well illustrated in FR Fig 6, which shows AOD with a calculated effect of -0.2 to -0.3C vs. MEI with +0.3 to +0.4C for the period immediately after the el Chicon eruption. If you look at the raw data (FR fig 1), the bulk of the cooling on UAH and RSS doesn't occur until 1985, a full 3 years after the eruption. That's not the volcano. The UAH graph shows a large cooling (-0.25 C) centered around 1985 with a 3-4 year duration, yet this is not labeled by UAH as 'el Chicon cooling'; the 1993 cooling is clearly labeled 'Mt. Pinatubo'. So Christy's contention that there are two volcanic coolings 'early in the record' is not correct.
  50. Foster and Rahmstorf Measure the Global Warming Signal
    muoncounter, relax. This level of scrutiny is applied to fake sceptics. Although, since their claims are for the most part so deattached from reality, one does not even need to apply much scrutiny at all to tell they are bunk. "A valid step towards establishing the most likely causes is to eliminate less likely factors from consideration. " Yeah, but... were volcanic aerosols or ENSO really "likely causes" of global warming? Volcanic aerosols have actually a cooling effect so they are excluded from the get go. ENSO is cyclical and cannot increase the energy in the earth system that is documented and that the ocean surface is hotter than the deeps. And we know that solar activity is actually decreasing while temperatures are on the rise. So I don't think that what FR2011 set to do was to eliminate those factors as causes of global warming. If that were the case, it would be a boring and redundant paper. In my view what they tried to do is to, knowing that global warming is primarily anthropogenic, remove the noise produced by other factors in order to see that anthropogenic signal more clearly. This is a subtle point, I understand that!

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