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CoalGeologist at 01:48 AM on 7 May 2010Kung-fu Climate
I am of mixed feelings as to whether a comment such as Poptech @#70 adds anything of value to a discussion such as this, but finally decided that it's worth including as an example of a logical fallacy variously referred to as "Moving Goalpost" or "Impossible Standards", etc. Despite an extensive discussion of how the HadCRUT temperature data are verified and corroborated by numerous other data sets, a "litmus test" was set forth by which the entire data is to be discarded as "worthless". In empirical sciences (such as geology and climate science, for example) we are frequently obliged to use data sets that are flawed in some manner, inadequately documented, etc. It's very tempting to just throw them away, which can leave us nowhere. The greater value is to use the data to their maximum advantage. This is what all the surface temperature data sets have been obliged to do (e.g. NOAA's GHCN) I have little doubt that the growing trend toward "transparency" in the global climate data will be continue to evolve, in response pressure from skeptics, particularly at the CRU. The challenge is not to fall down the "slippery slope" from skepticism to denialism in the meantime. By the way, if you are really keen on working with raw data, you might find what you are looking for at Rimfrost -
Ned at 01:43 AM on 7 May 2010Kung-fu Climate
skywatcher writes: Yep that's 0.3C/century difference, not, thank goodness, 0.3C/year! (before anyone quibbles, Ned's done the same thing and I'm sure he means +1.6 to +1.7C/century. Hahahaha, you're right. I can't believe I did that literally right after carrot eater had corrected you for the same slip-up. -
carrot eater at 01:36 AM on 7 May 2010Kung-fu Climate
Poptech: This is a pointless red herring. CRU and GISS match so far as the purposes here go, so it simply doesn't matter for the discussion here. If you want CRU to be as user-friendly as GISS - it simply isn't, at the moment. And it won't be, for some time - in some cases, CRU never even had the raw data; they have sometimes accepted homogenised date from the source countries (NOAA and thus GISS do not). Nor do they seem very organised in knowing which data they're allowed to publicly release. Nor does CRU have a simple computer program like GISS (and soon, NOAA) that reads in a file of raw data and spits out the answers. Some of CRU's homogenisations were done by hand, not computer algorithm. The way CRU has built it is fine for a normal research project. However, it's less optimal for a public resource used by many workers. So it's good that there are parallel efforts like GISS that give the same results anyway. So with the exception of the 1850-1880 period, it simply does not matter whether you use GISS or CRU here. Continuing to harp on it is not constructive in this context. The context is in discussing Loehle, not bookkeeping issues with CRU which are not relevant to Loehle. -
Jeff Freymueller at 01:29 AM on 7 May 2010Kung-fu Climate
#41 Humanity Rules, thanks for linking to the list for MBH98. I was under the impression that there were more proxy records from ice cores, corals, and other non-tree-ring sources available today. I don't have a list of those handy, though. -
Chris G at 01:28 AM on 7 May 2010Kung-fu Climate
FWIW, here is my perspective from watching the Kung Fu battles from my blimp. Temperature proxy studies in general: Useful as an independent measure of how much humans are affecting climate. Divergence of current patterns from previous patterns in baseline, variance, and rate of change can be estimated. These estimates can be useful for checking estimates derived from the physical properties of GHGs, insolation, changes in albedo, etc. But hey, they are proxies about temperature and don't touch what we know about absorption spectra of gases, Stefan-Boltzman, etc. Basic physics tells us that adding more GHG to the atmosphere, other factors remaining more or less constant, will raise the temperature at the surface; the questions are only by how much and how quickly. (And basic chemistry says that the pH of the oceans will change when CO2 levels change, but that is another topic.) Tree ring studies to determine past temperature: To be honest, these is kind of a 'meh' for me. The reason for this is that the rate of growth of a tree is a complicated function where the slopes for each factor don't always go in the same direction. That is, there are 'sweet spots' for any plant on any factor, a little less or a little more and the rate of growth declines. Last year was excellent temperature-wise for my cedars, but half my trees nearly died because it was too wet. My understanding is that Mann and the others tried to pick trees in locations where the limiting factor to growth was temperature, but climate change is not just temperature; it's also patterns of precipitation. I don't know how you look at a tree ring and tell how much water it got that year, and if the temperature gets above the comfort zone for the tree, you get the same decline in growth as if it were below. I don't know how you tell the difference. Mostly what you can tell from a thick growth ring was that all factors were not too far from the ideal for that species. Bottom line: temperature is a factor in tree growth; so, I'm sure there is a correlation and these studies are useful, but I'm not going to get overly excited about divergences between tree studies or tree studies and temperature records. If I'm missing something, please fill me in. -
Ned at 01:27 AM on 7 May 2010Kung-fu Climate
Poptech writes: So all that and still no raw data and methods for CRU. Why the obfuscation? I didn't ask for GISS, UAH or RSS, yet you provide me with what I did not ask for, fascinating. "Obfuscation"? I was trying to be helpful. It's not anyone's job here to "provide you with what you ask for." As far as I know, nobody here works for CRU, so posting demands here is unlikely to be an efficient way to get what you want. Nonetheless, I always try to be helpful, so here is a set of links to the CRUTEMP source code and data. If you have further questions about that, you should probably contact CRU directly. -
skywatcher at 01:18 AM on 7 May 2010Kung-fu Climate
Yep that's 0.3C/century difference, not, thank goodness, 0.3C/year! (before anyone quibbles, Ned's done the same thing and I'm sure he means +1.6 to +1.7C/century. Poptech, you're wasting everyone's time here. If you want the data and methods, go get the source data from the national met offices and use the methods outlined in the literature. If you can't/won't do that, then you're not in a position to quibble the data. You can generate an independent serioes from available online data as described here for GISS (gives essentially the same result), but I doubt you're interested in that either. -
KR at 01:09 AM on 7 May 2010Kung-fu Climate
Side note: Tree ring dating studies These get mentioned a lot, and I've seen some questions on how this is done. Understand that I'm not a tree ring dating specialist. However, I work with people who date tree rings, fish scale growth rings, etc., using software I write, and have some background as a result. Tree ring growth patterns can be strung together over generations of trees by normalizing growth rates. Early rings are thick (saplings grow fast), while later in their life rings thin out - they're larger, and even a larger mass increase is distributed around a bigger circumference. However, you can take a simple exponential fit to these and normalize the growth rates. You then match patterns of relatively thick or thin rings (good and bad years) to older trees, establishing how their lifetimes overlapped. Repeat as far as you can/as far as you have tree trunks, and you can extend the growth rate data out for centuries. The next step is trying to relate these relative growth rings to local conditions. That's a bit more of a stretch; different trees may have had different local sun/water/fertilizer conditions. But given data about how individual species perform under different conditions of temperature, you can estimate temperatures with sufficient tree data to average other local variations over the area your trees came from. I haven't seen much about correcting growth rates for other large region variations, such as CO2 level; can anyone comment on whether that variable is accounted for in tree ring data? Perhaps that (recent CO2 change) has an effect on the recent divergence of tree ring proxies from the temperature record? -
Alexandre at 00:52 AM on 7 May 2010Kung-fu Climate
Mann's Hockey Stick also has a no-treering (no-dendro) version that yiels pretty much the same results as far back as some 600 a.D. Here, graph b on page 13. -
KR at 00:40 AM on 7 May 2010Where is global warming going?
suibhne, if you fully read the link I provided, the journal policy states: "One unique feature of this journal is its review section which contains articles with permanent research value besides the state-of-the-art research work in the relevant subject areas. To ensure top quality, review articles are by invitation only and all research papers undergo stringent refereeing." (emphasis added) Note the difference between review papers, invited by the editors, and research papers that undergo refereeing. G&T was a review paper, invited by the editors, and not peer-reviewed. Note the difference. G&T claim that the last 100 years of climate research, GHG heat retention, and radiation thermodynamics are wrong. They are sadly mistaken, and their 150+ page polemic does nothing to support their position except push a bunch of incorrect jargon. (Seriously - if you have something to say in science you can usually state it in under 30 pages or so!) I do not agree with you about the photon selection issue, incidentally - that's quite a misread of what I said; I clarified my statements in #78. Heat engines cannot work without a temperature gradient, but photon excitation/emission events certainly occur. The energy flows in each direction are easily detected; you can't extract work from them in a case of radiative equilibrium because the net energy flow is zero. That's the basis of radiative equilibrium, a link you apparently haven't followed yet. Your statements in #83 about "all high energy levels being full" are complete nonsense. See an excellent description of heat radiation here. Ned, well put in #90. -
carrot eater at 00:32 AM on 7 May 2010Kung-fu Climate
Ned: Since RSS and UAH are not measuring the surface but an altitude range we might call lower troposphere, one wouldn't necessarily expect an exact match to the surface records. It'll be something similar, though, and should correlate pretty well. But yes, UAH has a shaky history, for whatever that's worth in assessing current discrepancies. -
robert way at 00:10 AM on 7 May 2010Antarctica is gaining ice
Cryosat-2 does have a better radar altimeter in comparison with previous radar methods (ERS and so on)therefore it hopefully will eliminate some of the resolution issues with previous methods of radar altimetry and can make up for the issues with icesat. (I'm thinking extremely small coverage area by comparison) -
Ned at 00:05 AM on 7 May 2010Kung-fu Climate
It's not surprising that all the different surface temperature analyses converge on +1.6 to +1.7C/year, since they're using basically the same data. There are some useful things that can be learned from comparisons among them: * There don't seem to be any significant problems with the code used by GISS or CRU, since other analyses give the exact same result. * The decline in numbers of high-latitude, high-altitude, and rural stations doesn't seem to affect the trend (or, if anything, it leads to a slight underestimate of the warming trend). * The reported surface trend is not an artifact of the "adjustment" process, since the trend is found using both raw and the adjusted data. The very close match between the surface trend and the RSS trend is more interesting, since they are based on completely different data and methods. Occam's razor suggests to me that if RSS and all the surface analyses agree exactly, and UAH is a bit lower, it's more likely that UAH is wrong than that UAH is right and the others happen to coincidentally hit on the same wrong result. Plus, of course, UAH has a history of substantial errors in the past. -
Riccardo at 23:58 PM on 6 May 2010Two attempts to blame global warming on volcanoes
tinsol, strong volcanism has a cooling influence, no doubt. But i'd not call it "a mechanism to cool down the Earth if it is getting to hot". Volcanism follows its own rules, unrelated to surface temperature. It can not "react" to warming or cooling. Underwater volcanism could in principle produce a warming of the oceans, but hypothesis need to be confronted with reality. Up to now no one could find any evidence for it, either direct (the known underwater volcanoes) or indirect (more warming at depth). -
carrot eater at 23:47 PM on 6 May 2010Kung-fu Climate
skywatcher: That's 0.3 C/century, not 0.3 C/year, if that's what we're after. Big difference. -
skywatcher at 23:45 PM on 6 May 2010Kung-fu Climate
My bad, Ned and Poptech, I mistook the 0.3C difference in anomaly as being what Poptech referred to, rather than the 0.3C per year difference in the trend (because Poptach referred to a value rather than a rate, and 0.3C is the difference in the anomaly values on the graph that was linked to). As your numbers show Ned, the trend in all measures is still significantly positive, which is the important point. -
carrot eater at 23:40 PM on 6 May 2010Kung-fu Climate
PopTech: "UAH trends 0.3C cooler" When discussing trends, you need units appropriate for trends - temperature/time. GISS gives something like 0.16-0.17 C/decade; UAH gives 0.13-0.14 C/decade. How you get "0.3 C" is beyond me. In any case, for the limited purposes here, GISS and CRU are essentially identical. But CRU goes back to 1850 instead of just 1880. Given that Loehle's work only extends to 1935 (1949, really), the extra years of overlap would be helpful in properly grafting on the instrumental record. *** I erred in my description at Part 4; they indeed used a fixed baseline. -
robert way at 23:40 PM on 6 May 2010Kung-fu Climate
The one thing that the author of this article did wrong was use the 700 papers site. They put papers on there that aren't even skeptical like André E. Viau et al. 2002. I've taken courses with that guy, and read all his papers, there's no way he's a skeptic. -
Ned at 23:39 PM on 6 May 2010Kung-fu Climate
CoalGeologist writes: That said, the presumption that there has to be some other explanation than AGW, because AGW couldn't be true, is what distinguishes denialism from skepticism. That's very well put. I would just add that skepticism implies critical examination of claims from all sides, whereas denialism is assymetrical in its view (disputing even the most robust claims from one side while credulously accepting nonsense from the other). All scientists should be skeptical (to an appropriate degree, of course). -
tinsol at 23:36 PM on 6 May 2010Two attempts to blame global warming on volcanoes
- maybe we dont have to worry about climate change because the Earth uses Volcanoes as a mechanism to cool down the Earth if it is getting to hot. We like to think we are more important than we are. We think it must be caused by humans because this global warming trend has happened in a relatively short period compared to other climate change historically. Its really hard to take into account all the possible variables like solar or lunar events, or anything natural that we are unable or haven't yet studied. There is a hysteria about this current media fad and that makes me suspicious. It doesn't sound scientific and the facts are Never fully released just the conclusions. Scientists are not the most biased people I know. They have careers to protect as well as ego. Also one study has shown that CO2 emissions on land have no bearing on climate change and that it is actually sea temperatures rising that is causing the changes on land. Therefore underwater volcanoes could be one of the causes of the rise in sea temperature or other natural causes. I am sure there are other studies out there. -
Ned at 23:29 PM on 6 May 2010Kung-fu Climate
skywatcher, there actually is about a 0.3C per century difference between the UAH trend and all the other trends. Here are the trends, 1979-present for the various temperature data sets (in degrees C/century): Satellite troposphere: UAH +1.3 RSS +1.6 Surface (land/ocean combined): HADCRU: +1.6 GISSTEMP: +1.6 NOAA NCDC: +1.6 Independent analyses (land/ocean combined): Nick Stokes: +1.7 Clear Climate Code: +1.6 Zeke Hausfather: +1.6 Of course, this is all a bit off-topic for this thread... -
carrot eater at 23:28 PM on 6 May 2010Kung-fu Climate
CBD: No, there is no attempt in Loehle to consider the spatial distribution of the proxies. Loehle's method is as bare-bones and simple as can be imagined. Loehle's method: 1. Take proxies with published calibrations. Assume the calibration was OK as given, and that the proxy was temperature-sensitive the whole time. Note to PopTech: at least some of the authors of the individual proxies probably calibrated against HadCru, so even Loehle's original work has CRU influence in it. 2. Interpolate low res series to annual basis (hopefully they did this in some reasonable way) 3. Smooth with 29-year moving average 4. Subtract from each series its mean (they didn't use a common baseline period? that seems like a mistake) 5. Take a simple mean There is no attempt to calibrate/validate the overall reconstruction, no attempt to consider the spatial distribution. -
suibhne at 23:18 PM on 6 May 2010Where is global warming going?
Ned Steve McIntyre is very good with numbers as the Hockey Stick man has found out. He is a mathematician not a Physicist. I think he was suggesting that people go to a site where Physics was the main thread. Perhaps he felt uncomfortable in a discussion where his own expertise was not central -
CoalGeologist at 23:06 PM on 6 May 2010Kung-fu Climate
In reply to HumanityRules @#27, I didn't mean to imply that the study of paleoclimate is not relevant to our understanding of contemporary climate change. It is important, and geologists have much to contribute in this regard, but we must remain cognizant of both similarities and differences in looking at paleo-analogs. At present, I'm persuaded by Penn State Professor Richard Alley's interpretation that variations in CO2 plays a (the?) predominant role in controlling surface temperature. Similarly, it is not just the right, but the duty of true skeptics to continue to search for alternative explanations for contemporary climate change and to "fine tune" our understanding of the 'biggest control knob(s)'. That said, the presumption that there has to be some other explanation than AGW, because AGW couldn't be true, is what distinguishes denialism from skepticism. -
skywatcher at 23:03 PM on 6 May 2010Kung-fu Climate
Unfortunately science doesn't work by demanding data, Poptech. To reproduce the results you should follow the methods of the researchers, which in this case would be to ask the relevant national meteorological organisations for their data, then following the relevant published methods. As GISS' methods and data are available, you can do just that, as Tamino and others have independently done in order to debunk D'Aleo and Watts. There's nothing in the paper you link to in (56) that questions Harries et al (2001) at all. Not a shred. Actually, Raschke's paper reads as a rather weak review that comes to few definitive conclusions. Another Tamino link to educate you on trends. 0.3C is not a trend. The baseline for UAH is higher than that of GISS, which is the reason that the anomalies for UAH are lower values than those of GISS, hence the 0.3C difference. The trend is the same, and is that of the anthropogenic warming. Looks like Ned got there before me - good post Ned! -
Ned at 22:59 PM on 6 May 2010Kung-fu Climate
Poptech writes: Could you please provide the Raw non-homogenized data and methods for HADCRU, thanks. If this is unavailable then I cannot scientifically reproduce this data and consider it worthless. If you don't trust the CRU global temperature data set, use the one from GISS. It's based entirely on publicly available data, the software is all public, and it's been exactly replicated by an independent team (see the Clear Climate Code project). Many other people have now found similar results using the same data but different programming methods, most though not all of which are open-source. Off the top of my head, these include Tamino, Zeke Hausfather, Ron Broberg, Residual Analysis, RomanM, Nick Stokes, and probably others as well. In fact, despite your complaints about HadCRU, Ron Broberg used the CRU gridding algorithms with the regular, publicly available GHCN data, and got basically the same results. There's a comparison of a few of these different analyses here:
Note that the HadCRU record, which you apparently don't trust, is essentially identical to the open-source one from GISS, and the one from NCDC, and the ones from independent bloggers (Zeke and Nick). And again, you can download and test out the code yourself for many of these analyses (GISS, Clear Climate Code, Nick Stokes's TempLS code, etc.)
Of course, if for some reason you don't trust any of those people, and you're not up for actually reading their code or writing your own, you could ignore the land surface temperature record entirely, and just consider sea surface temperature trends, which presumably don't have any Urban Heat Island effects. Kelly O'Day has a nice set of R scripts for downloading and processing climate data, including one for the long-term global SST trend, which -- surprise! -- also shows increasing temperatures:
.
Then again, if you don't trust sea surface temperatures, you could look at satellite measurements of temperatures in the lower troposphere, which also show an increase over the past three decades. (UAH's analysis has a slightly lower trend, but RSS's trend is a very close match for all the land surface temperature trend analyses).
Or, you could ignore all of that, and just assume that the climate science community doesn't make any of its data or software available so it's all a big hoax.
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Ken Lambert at 22:52 PM on 6 May 2010Tracking the energy from global warming
chris #106 The point is that the Sun is only doing 0.25W/sq.m from top to bottom of the 11 year cycle. You cannot argue that this accounts for the postulated 0.9W/sq.m imbalance in forcing. What the real Solar imbalance is underneath the 11 year cycle nobody knows. To know that - you need to know the pre-industrial equilibrium TSI - of which there is only proxy measurement. That assumes that the Earth was ever in equilibrium from Solar forcing which it probably never has been. The TIMS TSI is still 4.5W/sq.m lower than earlier satellite TSI readings - low accuracy but high precision. The average ocean depth is 3700m and we are covering the top 700-900m with Argo of unproven accuracy. The other approx 3000m is largely unknown and no real mechanism is known to get the heat down there in months to years time frames. Lots more accurate measurement is needed to find out what is really happening here. -
Steinadler at 22:18 PM on 6 May 2010Kung-fu Climate
Steinadler wrote: It seems to me that the "MWP" does, in a sense, rather tend to confirm the gravity of our predicament. It doesn't really matter if present conditions are slightly warmer or about as warm as one of the very few equally warm periods over the last few thousand years. Either way, the warming effect of anthropogenic CO2 emissions will be adding to an already quite unusually high temperature as far as the history of humanity goes, and the resulting temperature may, from what I've understood, be without precedent for the entire lineage of the hominidiae. HumanityRules wrote: Your approach suggests to me that you presuppose that the climate’s sensitivity to CO2 is equivalent to society’s sensitivity to climate. It suggests a belief in the impotence of modern society, not something I'd buy into. ___ I don't see much of any such suggestions in the little text I posted, though from your reading I'll have to accept that such an interpretation is evidently possible . And I try not to hold any belief, one way or the other. Surely, modern societies consist of more or less enlightened people, and the question is, then, who will prevail. The outcome will of course depend on whether a number of societies will be able to face up to the scope and size of the challenge, as suggested by science. -
Ned at 22:15 PM on 6 May 2010Where is global warming going?
suibhne writes: However being a practical man [...] With all due respect, an actual "practical man" knows that when he's in a hole it's time to stop digging. There are many less nonsensical arguments against the IPCC consensus than the one you've chosen to make your stand on. I'm not going to speculate about what motivates you to be so persistent and vocal in defense of obvious error, but practicality pretty clearly has nothing to do with it. Steve McIntyre is a very practical man. You don't see him posting about G&T on his blog (in fact, he's banned discussion of it because he knows that hosting that kind of nonsense would damage his site's credibility). There's a lesson there. -
CBDunkerson at 21:50 PM on 6 May 2010Kung-fu Climate
Poptech, look at that quotation from Loehle you posted again. Yes, it says that the MWP was 0.07 C warmer than the 'end of the 20th century'... but it also sets the 'end of the 20th century' at 1992. Thus, in one sense 'both sides' here are right. Loehle's statement is correct for an 'end of the 20th century' as he defined it (i.e. 1992) and with his other data and assumptions. However, if we set the end of the 20th century at the year 2000, as most people would have it, then the modern temperatures are higher... even using all Loehle's data sources, methodologies, and other assumptions. That said, I think there is a very fundamental flaw in Loehle's approach. As I understand it he makes no attempt to weight the different proxy readings geographically. So... the 15 proxies from the Northern Hemisphere actually have 67% more impact on his recreation of >Southern< hemisphere temperatures than the 3 proxies actually FROM that hemisphere do (15/18 - 3/18 = 12/18 = 67%). An extreme example of the flaw to this approach would be to take 5000 samples all from Canton, Ohio, average them, and then say that result is a valid proxy for average global temperatures with a huge sample size. It only works if we assume that temperatures change uniformly across the globe... which even Loehle's 18 proxies show not to be the case. Thus, knowing that temperature changes are NOT uniform geographically, the logical course would seem to be to apply the data we have from each region.... the most simplistic example would be to use the average of the 15 NH temps to get a NH result and the 3 SH temps for the SH and then average those two numbers together. Since most data now shows the MWP to have been a NH phenomenon this would decrease its apparent impact on a global scale... and thus yield results more in line with the other studies. It is only by over-representing northern hemisphere data as the primary determinant for the entire planet that Loehle gets his MWP anywhere near modern temperatures. -
oamoe at 21:34 PM on 6 May 2010Kung-fu Climate
Since the UAH and RSS calculations of average global temperature anomolies from microwave satellite data are in almost perfect lockstep agreement with the direct surface measurements (Hadley, GISS) since 1978, why should we not have complete faith in the Hadley dataset? -
skywatcher at 21:18 PM on 6 May 2010Kung-fu Climate
Poptech, I would suggest you look at John Cook's: http://www.skepticalscience.com/human-fingerprint-in-global-warming.html The evidence is not based on models, as you imply. The CO2 warming effect was predicted over a century ago, and CO2's warming has been directly observed by Harries et al (2001) and a number of subsequent papers. These are direct observations, not models. As for datasets, you can see the sources, methods and code of the GISS dataset, and the raw data is available for HADCRU if you go get it yourself. Seeing as these datasets independently match each other, and also correlate with the satellite records, all showing the warming of the last three decades, faith is not required when identifying the warming trend of Earth. -
skywatcher at 20:42 PM on 6 May 2010Kung-fu Climate
I was going to make a comment about the hockey stick and climate sensitivity, but robhon you beat me to it (excellent article by the way). What's the value of the 'hockey stick'? 1) A crucial foundation pillar of AGW theory, without which the whole thing crumbles into dust? 2) An interesting byproduct of palaeoclimate analyses that informs us on climate sensitivity, but tells us little about whether humans are driving global warming? 3) A visually arresting image that appears to show that humans are driving warming, good for showing politicians and the general populace? These are interesting questions as skeptics, such as Arkadiusz would have you believe (1), but would utterly ignore the implications of (2). (3) is almost a red herring for both sides, precisely because (1) is incorrect and (2) is correct. The most important point is this: "What if Loehle (and similar arguers) was right?" What are the implications for present/future climate change? The implications are that the Earth in it's present configuration is much more sensitive to changes in radiative forcing than we currently think. Meaning that the future changes in response to our forcing would be truly catastrophic, many times what the IPCC suggest. Do "skeptics" really want that? Skeptics really ought to hope that Mann was right (I think he is as regarding regional variation and global significance), that the Earth's sensitivity is lower to radiative forcing change! But because of the political element in (3), skeptics could not bring themselves to say that Mann is right... Of course that does not change the political element as embodied by (3), that the hockey stick is a stunning visual indicator of our impact on global climate. The stick, and distant palaeoclimate, does not inform us on the mechanisms, as excellently pointed out by CoalGeologist because the driving mechanisms and elements of the system are not the same now as they were. -
johnd at 20:39 PM on 6 May 2010Kung-fu Climate
Can someone clarify at what point, and the process by which, the data collected for these temperature reconstructions becomes an indicator for global temperatures. I assume that whatever the chosen indicator is from which measurements are collected, lets says tree rings, at some point the measurements taken will have been matched to actual temperatures recorded for the corresponding period. These temperatures should by rights be the temperatures recorded at the location where the chosen proxy was measured, it makes no sense to match them to a temperature recorded at some location remote from, or unrelated to the site that the measurements were drawn from. When the historic temperature record is then reconstructed, it also will then obviously be valid only for that specific location. How do those reconstructions then become indicators of global temperatures? -
ProfMandia at 20:03 PM on 6 May 2010Kung-fu Climate
For those of you interested in the Hockey Stick debate, here is a good link: A Layman's Guide to the Science and Controversy: 5. Temperature Reconstructions Scott A. Mandia, Professor of Physical Sciences Selden, NY Global Warming: Man or Myth? My Global Warming Blog Twitter: AGW_Prof "Global Warming Fact of the Day" Facebook Group -
Arkadiusz Semczyszak at 19:23 PM on 6 May 2010Kung-fu Climate
a propos: "... appropriate statistical tests that link the proxy records to observational data ..." - I propose this paper: Esper J, Frank DC, Büntgen U, Verstege A, Hantemirov RM, Kirdyanov AV (2010) Trends and uncertainties in Siberian indicators of 20th century warming. Global Change Biology 16, 386-398. -
HumanityRules at 19:22 PM on 6 May 2010Kung-fu Climate
42.Steinadler Your approach suggests to me that you presuppose that the climate’s sensitivity to CO2 is equivalent to society’s sensitivity to climate. It suggests a belief in the impotence of modern society, not something I'd buy into. -
Arkadiusz Semczyszak at 19:00 PM on 6 May 2010Kung-fu Climate
# 2 Spencer Weart "The MWP may therefore not have been a global phenomenon, and indeed this is what Mann's most recent work tells us." Treydte et al., 2009 ? Well, yes. Kung-fu. "Scientific War". There is, however, is described (mostly) the methodology to create the reconstruction of temperatures. And some of them should disappear (do not create unnecessary noise) because that is defective (very flawed) methodology. Only Loehle? For example, Gerd Bürger of Berlin's Institute for Meteorology, he writes about one of the reconstruction: - "Osborn and Briffa did not apply the appropriate statistical tests that link the proxy records to observational data, and as such, Osborn and Briffa did not properly quantify the statistical UNCERTAINTIES in their analyses.", "As a result, the ‘highly significant’ occurrences of positive anomalies during the 20th century DISAPPEAR.", "The 95th percentile is exceeded mostly in the early 20th century, but also about the year 1000. [...]" It would be worth Loehle used the latest scientific description proxies (particularly the work of the last three years), covering the end of the twentieth century (perhaps it does?). Appeared here at least a dozen works, including some very clearly show the MWP on SH (most interesting for me - already cited - is: von Gunten, L. et al. 2009. A quantitative high-resolution summer temperature reconstruction based on sedimentary pigments from Laguna Aculeo, central Chile, back to AD 850.). Supporters of such phenomena as localness MWP, LIA, even applying the most exquisite Kung-fu (Treydte et al., 2009), can not pass by when such works as (my favorite - interesting references): Selvaraj et al. 2008, Holocene weak summer East Asian monsoon intervals in subtropical Taiwan and their GLOBAL SYNCHRONICITY". Interesting are also: Licciardi et al., 2009, Holocene Glacier Fluctuations in the Peruvian Andes Indicate Northern Climate Linkages - "The results bring us one step closer to understanding GLOBAL-SCALE PATTERNS of glacier activity and climate during the Little Ice Age," said Licciardi; Trouet et al., 2009, Persistent Positive North Atlantic Oscillation Mode Dominated the Medieval Climate Anomaly, - "... MCA-LIA climate transition that probably was coupled to prevailing La Niña–like conditions amplified by an intensified Atlantic meridional overturning circulation during the MCA." If this is all true ... - La Niña is a global phenomenon - MWP-MCA - simply CAN NOT BE local. -
suibhne at 18:59 PM on 6 May 2010Where is global warming going?
doug_bostrom ...What do photons emitted from a cool body do when they encounter a warmer body? ....... Think of the basic physical reality of the situation. 1. The mass of the Earth against the mass of atmospheric CO2 2. The ability of the Earths surface to radiate at all wavelengths within its spectrum centred around 15c. 3. The restriction that CO2 can only emit at a few wavelengths. The energy envelope of CO2 centred around -10c Would the tiny number of low energy photons from CO2 make any difference to the massive number of higher energy photons leaving the Earth. I don't think that even the most sensitive measuring device could detect any effect in the Earth surface temperature. However being a practical man if you can produce a realistic device that does work from the "backradiation" I will find your viewpoint much more convincing -
Mythago at 18:39 PM on 6 May 2010Kung-fu Climate
Rob, Excellent article. I agree with what Professor Scott Mandia said early in the comments. You have explained it all very well and made it easier to understand for the laymen and women out here. The first thing that struck me was that the fig 3 graph with all the data sets on it looked like they were all the same and all going in the same direction. All of them look like 'hockey sticks' so what I said previously still stands. We know its happening so we need to stop arguing over trivial data points and get down to basics. The need now is to stop doing what we are doing that's causing the problem and change course before we hit the rocks, or in aviation terms when heading towards a mountain side pull up quick before we reach the point of no-return. I know its not exactly a point that falls easily into this discussion forum but I really do get heartily sick of wasting my time with sceptics who will not change their opinion even when the truth hits them square between the eye's. I hope that I am not seen as stating the bleeding obvious but instead showing support for your efforts. I do use your site as a source to educate those who are genuinely interested in knowing what is happening. Many thanks. Kev C Part-time OU Student, UK. -
suibhne at 18:35 PM on 6 May 2010Where is global warming going?
scaddenp Thanks for the link. Read Terry Oldbergs comments in the Tread he puts the case for G&T much better than I can. -
Steinadler at 18:25 PM on 6 May 2010Kung-fu Climate
@CoalGeologist It seems to me that the "MWP" does, in a sense, rather tend to confirm the gravity of our predicament. It doesn't really matter if present conditions are slightly warmer or about as warm as one of the very few equally warm periods over the last few thousand years. Either way, the warming effect of anthropogenic CO2 emissions will be adding to an already quite unusually high temperature as far as the history of humanity goes, and the resulting temperature may, from what I've understood, be without precedent for the entire lineage of the hominidiae. -
HumanityRules at 18:00 PM on 6 May 2010Kung-fu Climate
38.Jeff Freymueller Here's a list of Mann's proxy's. I don't fully understand it but does Mann only use 18 non-tree proxies as well? -
roundton at 18:00 PM on 6 May 2010Kung-fu Climate
Thanks, Rob, for this post, which contrasts with the somewhat dreary and predictable tone that tends to characterises this blog. There's obviously scope for more work to be done on recent (i.e. during the present interglacial) paleoclimate, as I'm sure both Loehle and Mann would agree. When we've done with the MWP, then there's the (possibly even warmer) R (Roman) WP to consider. Climate varies, and has always done so. A source of plentiful references to literature on the MWP is the climate sceptic site www.co2science.org In the end paleoclimatology still leaves us with the question as to what has been happening to the earth’s climate during the last 150 years or so. There is a whole range of potential climate forcings which on theoretical grounds one might expect to have influenced, and in some cases raised, surface temperatures. Many of these forcings are anthropogenic. The net effect of all the known and unknown influences appears to have been a fluctuating upwards trend in surface temperatures. Disentangling the various forcings, in particular the anthropogenic ones, is not going to be a simple task. However a start on this task has been made by the group of workers associated with Colorado meteorologist Roger A. Pielke Snr. Pielke is not a climate sceptic - he believes in an anthropogenic influence on climate. He and his co-workers have an impressive list of peer-reviewed articles to their names, although there is little or no consideration of their work in the IPCC WG1 reports of 2001 or 2007 However this literature is referenced at Pielke’s blog www.pielkeclimatesci.wordpress.com -
RSVP at 17:53 PM on 6 May 2010Rain in the Canadian High Arctic in April?
Perhaps that could be a new skeptical argument... "too much data", or "too much new data". -
HumanityRules at 17:14 PM on 6 May 2010Kung-fu Climate
34.scaddenp Can you get estimates of forcings based on changes in atmospheric temperature? An El Nino can raise the global temperature by releasing more energy from the ocean without any change in radiative forcing. Ocean circulation can work on time scales of upto 1000years, can changes in energy release from the ocean work on these scales? Again Trenberths "missing energy" has one explanation in novel ocean processes that bring the deep ocean into play. To what extent can we rule out changes in ocean energy exchange rather than (or in combination with) changes in radiative forcing to explain changes in atmospheric temperature? The discussion of energy budgets in an earlier posting got me thinking of the atmosphere more as a conduit for energy transfer between the oceans and space. I think the variation of energy coming into the earth from the sun (or lack of it) has been well discussed on this website. And alot of time is spent on the transfer of energy through the atmosphere. But I haven't seen alot about the role of the oceans and the processes of energy transfer back to the atmosphere. Maybe this is just the wrong way to think about things and completely irrelevant to this discussion but it's something I've been puzzlinmg since the Trenberth / Pielke discussion. -
Jeff Freymueller at 17:01 PM on 6 May 2010Kung-fu Climate
Nice work, Rob. Two questions come to mind. The first is that there must be far more than 18 non-tree proxies available, right? So how did Loehle select the 18 that he used? The second is how many of the proxies shown in the final figure are independent -- based on totally different data? If some are independent, they could be averaged to reduce random errors -- by eye an average of any two or more of the curves would tend to look more like a ... hockey stick. On the point of noise and averaging, one obvious drawback of using only a few records is that you can't average down noise. In the presence of noise (or non-climate variation), you would expect that a reconstruction based on fewer records will show more variability simply because of noise. What did Loehle give for the error bars on his reconstruction? Only with the error bars on the plots can you tell whether the variations are likely to mean anything. This is the biggest reason I prefer the IPCC's version of this kind of figure: they show the error bars through a shaded region. -
mothincarnate at 17:00 PM on 6 May 2010Kung-fu Climate
Great write up, as always. I've recently ended up in a fight with an economist from NZ which has ended in a stalemate position with the science only reflected on one side of the debate. For very much the same reason as you summed up at the end of the piece, that's why I am where I am. I have a 10yo son and thinking about him I often find myself wondering why are we watching a fight which doesn't seem to address the point, when regardless of the slope, we are obliged to do our best to leave the place better than we found it. Nothing would be worse than watching him enter the workforce having to address issues that I was aware of and did nothing to mitigate in any way. As with this debate I found myself getting wrapped up in; focusing on such a fight itself induces a form lethargy instead of action. Anyway, cheers for putting the fighter in the same ring together so we can get a good look at what the fight is truly about! Tim -
nautilus_mr at 15:15 PM on 6 May 2010Kung-fu Climate
The Hockey stick is far from discredited -and certainly not by McIntyre and McKitrick. Readers interested in reading what the 'smartest guys in the room' have written about M&M should look at RealClimate's guide to the Hockey stick. NASA's Gavin Schmidt uncovers the failings of M&M 2007 in detail here. -
Doug Bostrom at 15:11 PM on 6 May 2010Kung-fu Climate
So no specific complaint about the Hadley data Poptech was griping about. In any case, fortunately science does not work by having researchers slavishly following scripts produced by earlier workers, so even if there were a problem there we'd have already seen it. In fact, the "problem" Poptech is worried about turns out not be any problem at all but rather an advantage. Thanks for helping to clear that up, Poptech.
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