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chris at 10:34 AM on 11 July 2010Hotties vs Frosties?
Berényi Péter at 08:21 AM on 11 July, 2010 The evidence surely supports the conclusion that "global warming is still happening", doesn't it Peter? Sea levels continue to rise at a rate that is larger than can be accounted for by the apparent mass increase (indicating continuing heat uptake), and the measures of ocean heat uptake although seemingly reduced during the period between around 2003-7/8 are positive if one includes estimates of ocean heat at depths [Murphy et al. 2009 and other direct measures of deeper ocean heat uptake (e.g. [*])]. The land ocean temperature index indicates that the Earth surface is warmer during the last 12 months than any previous 12 months in the record. So global warming is still occurring, even if there has been a short time period during which the apparent uptake of heat into the oceans may have been reduced somewhat. It might be preferable to state "The evidence supports the conclusion that global warming is still happening although there is some uncertainty in balancing the heat and sea level budget during the period 2004-2008." And there's also the rather philosophical problem relating to the progression of events (with inherent variability) into the present and future! After what period of time are we justified in stating that global warming is or isn't continuing? At the end of 2008 when there had been a short downturn in surface temperature and sea level could we conclude that "global warming is not still happening"? Not really, even though you attempted someting like that in a previous post with your fit of a truncated sea level dataset to a quadratic to infer a deceleration; 18 months later the surface temperature is near a high record, the sea level rise has recovered such that it's pretty much smack on the decadal trend, and the quadratic fit of the full record is more or less equivalent to a linear fit. So obviously we need to be careful not to jump to conclusions based on events occuring during short time periods. P.S. In a post above you asked: "Even better, show us references to the peer reviewed literature where the problem is discussed." It's discussed in Cazenave (2009) and Leuliette and Miller (2009) cited below, as well as in these papers [**](amongst others). [*] e.g. Cazenave A et al. 2009. Sea level budget over 2003–2008: A reevaluation from GRACE space gravimetry, satellite altimetry and Argo. Glob. Planet. Change 65:83–88 who estimate a 0.37 (+/- 0.1) mm.yr-1 heat uptake contribution to sea level rise during 2003-2008 based on ARGO data down to 900 metres. see also Leuliette E, Miller L. 2009. Closing the sea level rise budget with altimetry, Argo and GRACE. Geophys. Res. Lett. 36:L04608 who estimate a 0.8 (+/- 0.8) mm.yr-1 heat uptake contribution to sea level rise during 2003-2007 from ARGO data. see also papers from Johnson et al who find significant recent heat uptake in the deep oceans: Johnson GC et al. (2006) Recent western South Atlantic bottom water warming Geophys. Res. Lett. 33, L14614 Johnson GC et al. (2007) Recent bottom water warming in the Pacific Ocean J. Climate 20, 5365-5375. Johnson GC (2008) Warming and Freshening in the Abyssal Southeastern Indian Ocean J. Climate 21, 5351-5363. Johnson GC et al. (2009) Deep Caribbean Sea warming Deep Sea Research. 1 –Oceanograph. Res. 56, 827-834. [**] A. Cazenave and W. Llovel (2010) Contemporary Sea Level Rise Annu. Rev. Mar. Sci. 2010. 2,145–73 K.E Trenberth (2009) An imperative for climate change planning: tracking Earth’s global energy Curr. Op. Environ. Sustain. 1, 19–27 K. E. Trenberth and J.T. Fasullo (2010) Tracking Earth’s Energy Science 328, 316-317. -
johnd at 10:22 AM on 11 July 2010Tai Chi Temperature Reconstructions
Peter Hogarth at 10:06 AM, it's not actual numbers that is important within itself, but whether or not those numbers are representative of the whole environment under study. Hovering around 50% selection as a start is hardly representative, especially when further attrition can be found as the processing continues. As the quality and quantity of data collection advances, any modelling for reconstructions of earlier periods must be validated against the most recent data. Having done that, the earlier reconstruction data cannot then be used as validation of the later data. It's the cat chasing it's own tail. -
Philippe Chantreau at 10:15 AM on 11 July 2010Hotties vs Frosties?
BP you have already proven in the ocean acidification thread that you are looking for certain things in the data, that you will find them even if they are not there and that you will share with all your emotional response to what is not there. You're doing it again now with the "rather weird" and other comments. Yet, once again, you have only taken a superficial look, and fall far, far short of the standards to which you are willing to hold everybody else. I'm not impressed with you claiming some sort of high ground while systematically suggesting ill intentions in every piece of science that you dislike. Especially when such suggestions are based on nothing more than a biased, cursory look. Drop the accusations if you can't back them up with something really solid. -
Peter Hogarth at 10:06 AM on 11 July 2010Tai Chi Temperature Reconstructions
johnd at 09:39 AM on 11 July, 2010 That’s some back yard John!
How many trees over what sort of area would you find to be a convincing sample? I think these researchers have used sufficient numbers. Their methodology is fully explained and makes sense. Why would they use later data to validate anything when they are specifically looking for DP or late 20th century effects in the later set? surely they would use earlier (presumably less affected) data as reference?
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johnd at 09:39 AM on 11 July 2010Tai Chi Temperature Reconstructions
Peter Hogarth at 08:21 AM, I think it is very clear that the term "site" can only refer to a collection of individual trees, trees which in this case had been predetermined as being able to reflect temperature changes. As for the number of trees per site, the average number of larch trees in a site appears to be 50, and the average number of spruce trees appears to be 26. That is not many trees nor likely a very big area. In fact my back yard would have more fully grown trees than the average spruce site and possibly the average larch site as well. However given that only about half the available sites were selected seems to indicate that there was only an 50/50 chance that the trees would adequately reflect the correlation required, so that opens up the possibility that something other than the trees has a deciding influence, perhaps something related to the site conditions rather than the tree species itself, perhaps even the divergence problem was evident at those sites not selected. Can Buntgen legitimately claim a greater than 50% confidence, a toss of a coin, in their findings based on their selection process? They should at least explain why the high rejection rate. Another factor that reduces the number of effective trees under study is their age. Using larch as an example, the trees ranged in age from 65 to 447 years, the average 210 years. Given the total period of the study was 1864-2003, 139 years, a certain proportion could only be tracked for a reduced portion of the study period. However that is diverging away from why my confidence was perhaps not as inspired as yours. It seems to me that given one set of data covered the period 1864–1933 and the other 1934–2003, it should be that the latest set of data should be what is used to validate the earlier set, not the other way around as was done in the Buntgen 2008 study. -
Rob Painting at 09:32 AM on 11 July 2010Hotties vs Frosties?
"Furthermore, there is the (not well advertised) issue of different adjustment procedures being applied to US data and the rest of the world." - BP And what exactly would that be?. -
Berényi Péter at 09:02 AM on 11 July 2010Hotties vs Frosties?
#25 carrot eater at 22:40 PM on 9 July, 2010 Anybody can take the existing data sets and analyse them in their spare time, with no funding at all I am doing just that. Downloaded GHCN v 2.0 data, selected USHCN stations, and analysed adjustments done in v2.mean_adj.Z (relative to v2.mean.Z). The result looks like this:
The adjustment pattern is rather weird. Middle line (red) is average adjustment for each month, upper (yellow) and lower (blue) lines are 1 sigma error limits.
We can see a rather smooth adjustment trend (and two discontinuities around 1918 and 1950) with an upward slope which accounts for a good portion of 20th century warming in the US. Also, the dispersion of adjustments is huge compared to the trend. And there is a large seasonal signal of smoothly varying strength. Beyond April 2006 adjustment is zero.
With no further explanation it does not increase one's confidence in surface temperature reconstructions done by professionals.
Legitimate adjustments necessitated by instrumental bias simply can't look like this.
Furthermore, there is the (not well advertised) issue of different adjustment procedures being applied to US data and the rest of the world.
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KR at 08:47 AM on 11 July 2010Sea level rise is exaggerated
Daniel - Something you haven't really addressed (at all, and I don't count your ad hominem statements) is that the paleo data indicates sea level, not sea level rise rate. The rise rate is extrapolated by looking at multiple measurements of sea level. I've said it before, but it didn't seem to register - if a major upswing like the currently observed 2.4 mm/yr SLR occurred in the 1300-1850 period, the paleo data points of sea level couldn't fall anywhere close to the linear fit line for the 1.0+/-0.2 mm/year SLR trend. If there was a brief 100-150 year rise at 2.4 (as currently observed) there would be a step change in the observed paleo sea levels. That is not shown in the data. The only way a rise at those rates could occur and still fit the data (including the error bars) would be if the SLR went negative (or close to it) long enough for the long term sea levels to still average 1.0+/-0.2 mm/yr. If you have a physical process for something like that, I would love to see it. If this was measuring rate of rise, there are a lot more degrees of freedom. But these measurements are of sea level, and the long term historic rate is clearly about half the current rate. That's why I said "reversible", and why I don't feel your hypothesis of high variability and equally high rise rates in the past can hold, unless you also postulate extremely low SLR levels. The current rate of 2.4mm/yr is well established by tide gauge data, Donnelly submits evidence for ~1.0mm/yr for the 1300-1850 era - and your graph fit falls within his error bars for that rate. Sparse data or not, if a high SLR rate occurred in that period, it would have to be matched by a low SLR rate for the long term trend in sea level to still be ~1mm/yr. If you don't get that, well, end of discussion for me. I'm not going to waste my time yelling at the deaf. -
CBDunkerson at 08:33 AM on 11 July 2010Hotties vs Frosties?
gallopingcamel #55 wrote, "You folks are mostly with the IPCC that predicts a warming as high as +4.0 Kevin per doubling of CO2 concentration. IMHO +0.5 Kelvin is a much more likely figure." Radiative physics suggests a figure of just under 1 C from the CO2 alone without considering any feedbacks. Thus, to get to a 0.5 Kelvin/Celsius result we'd have to assume significant negative feedbacks. However, measured results show a very different story. We passed +0.5 Kelvin a couple of decades ago and still aren't anywhere near a doubling of CO2. Ergo, your "much more likely figure" has already been exceeded by the measured warming... which indeed is now nearly double that amount. This suggests positive feedbacks and leads to the '2 C minimum / 3 C most likely / 4.5 C possible' values now being projected. -
chris at 08:30 AM on 11 July 2010Hotties vs Frosties?
Berényi Péter at 05:43 AM on 11 July 2010 #8 perseus at 19:06 PM on 9 July, 2010 "Despite Kuhn’s theories, the peer review procedure, a dedication to the truth, and sometimes quite fierce competition amongst scientists should prevent ‘Warmists’ becoming over-partisan." I think there is some truth in that, although it would be more realistic to broaden the peer-review procedure to include all of the pre-publication peer assessment that involves (i) presentation of one’s work at group seminars; presentation at departmental seminars, (iii) presentation at scientific meetings. Published work of any importance has usually gone through an extensive peer review process of this sort before a paper is submitted, and work of any merit is generally submitted in the expectation that it will be published. Berényi Péter at 05:43 AM on 11 July 2010 "There was also a secret motive, to compensate for declining willingness of people to take personal responsibility and increasing reluctance of society to accept responsibility and conscience as assurances." I’m not sure there’s much evidence for that Peter. Peer review in its modern form is largely a means of spreading the burden of quality assurance away from journal editors in the light of a huge increase in scientific publication, and establishing a more reliable and systematic means of maintaining the quality of published work. One of the often forgotten things in these dreary times where everything is subject to “politicisation”, is that peer review is simply a good way of improving the quality of published work. It’s blindingly obvious that those with expertise in a subject are best suited to addressing real or potential flaws, inconsistencies or confusions, and generally to improve the presentation and to offer thoughts and suggestions. In my experience that’s a major element of peer review (‘though it doesn’t always work so nicely). More significantly, Perseus’s comments about “dedication to the truth”, and yours on “declining willingness of people to take personal responsibility”, are the diametrically opposed idealistic (perseus) and cynical (Peter) views of science and scientists. I believe perseus is far closer to the reality. The large majority of scientists are motivated by doing good work, finding out stuff, hopefully something quite important occasionally, and making a productive contribution to their field. It’s the inherent integrity (their “willingness to take personal responsibility”) of the large majority that make scientific publishing (and the peer review part of this) rather successful. I would say scientists recognise that they have an individual and collective responsibility to get things as right as they are able. Likewise scientists interact with a natural world that has an inherent reality (there are philosophical viewpoints that dispute that!), and their work and interpretations are constrained by that reality. Despite many efforts by pseudoscience misrepresenters it is simply not possible to maintain the deceit, for example, that smoking cigarettes doesn’t increase the risk of cancer, or that oil can’t form naturally since it’s seemingly impossible for “low chemical potential biological detritus to high chemical potential hydrocarbons with no external free energy source” (false premise)... and so on. The inherent reality of the natural world can be considered a fundamental element of peer review. Your example of the journal “Homeopathy” is another example of unnecessary cynicism. If one wishes to trash a process (like peer review) one may wish to root around for the dismal examples with which to flay the entire process. But science, and scientific publishing will survive “Homeopathy”! Much like “Energy and Environment” we can recognise it for what it very likely is. I’m not going to comment further on “Homeopathy” since I haven’t looked at the journal in detail. However it’s unlikely to be an important element of the progression of scientific knowledge since no one seems to cite the papers there (it has an Impact Factor of around 1). So not a great problem really, 'though it might be wasting rather a lot of money and effort to little effect. -
Berényi Péter at 08:21 AM on 11 July 2010Hotties vs Frosties?
#68 chris at 08:03 AM on 11 July, 2010 Who said anything about "proof" Peter? What an odd thought! You are right, it is never proof, it is picture. Is global warming still happening? "Combined with the results of Murphy 2009, we now see a picture of continued global warming" -
Peter Hogarth at 08:21 AM on 11 July 2010Tai Chi Temperature Reconstructions
johnd at 10:01 AM on 10 July, 2010 John, you may be confusing selection of sites with selection of individual trees when you state: “It relies not only the selection of species, but the selection of individual trees whose growth is considered to faithfully represent a robust relationship between growth and temperature” and you then quote a section from the abstract which refers to selecting numbers of sites? Reading past the abstract, “A dataset of 3069 larch and 1600 spruce TRW series from 124 sites (62 per species) distributed across the European Alps was compiled” We then see that 64 sites are selected from the network of 124 sites, but this is spread over a wide geographical area and each site may contain hundreds of individual trees. The methodology for site selection is discussed. I would hope this increases your confidence? I suggest you will find the later references from Esper and Buntgen very interesting, it is not that the DP has been disproven or dismissed, just found to be more prevalent at sites of high latitude or elevation (for example), and not as widespread as previously assumed. From Buntgen 2009 “Therefore, the DP should not be thought of as an endemic large-scale phenomenon with one overriding cause, but rather a local- to regional-scale phenomenon of tree-growth responses to changing environmental factors including multiple sources and species-specific modification” -
Berényi Péter at 08:11 AM on 11 July 2010Hotties vs Frosties?
#37 Lou Grinzo at 23:56 PM on 9 July, 2010 I don't see how anyone can escape the conclusion that further delay in reducing our CO2 emissions would put us on an almost unimaginably bad path Are you advocating quick development and en masse deployment of either uranium or thorium based breeder reactors? If carbon dioxide is such an evil thing, there is no other commercially viable alternative. Just do the math. Am . J. Phys. 51(1), Jan. 1983 Breeder reactors: A renewable energy source Bernard L. Cohen Department of Physics. University of Pittsburgh, Pittsburgh, Pennsylvania 15260 -
chris at 08:03 AM on 11 July 2010Hotties vs Frosties?
Berényi Péter at 07:41 AM on 11 July 2010 "Until that time stop citing this paper as proof of warming...." Who said anything about "proof" Peter? What an odd thought! Is there a problem with Murphy 2009 and Levitus 2009 etc? Well yes, they're very unlikely to be fully correct are they? That's the nature of science in the delightful areas of uncertainties. In this particular arena there are some confusing uncertainties especially during a rather short period where the apparent OHC is seemingly incompatible with TOA radiative imbalance and the sea level rise doesn't quite match the apparent independently determined thermal and mass contributions. So it's a little bit of a mess right now wouldn't you say? But what is to be gained by continually pointing this out and prodding it like a sore tooth? Why not simply embrace this little uncertainty, and wait for the interesting developments that are sure to shed light on it in due course. However much one redisplays the graphs and fiddles around with the numbers we're probably not going to come with the answers on this blog. Of course you might come up with some interesting theories, and that can be quite entertaining. Otherwise I would suggest avoiding using uncertainties in sub-issues (however delicious these often are) to support dubious brutalist deductive "logic" whereby one chooses one's conclusions and then rummages around in the uncertainties to construct premises that support these. It isn't very scientific. -
Berényi Péter at 07:53 AM on 11 July 2010Hotties vs Frosties?
#48 e at 02:36 AM on 10 July, 2010 This is a blog, we aren't performing the scientific method here I see. -
Berényi Péter at 07:49 AM on 11 July 2010Hotties vs Frosties?
#52 kdkd at 09:00 AM on 10 July, 2010 The only people who claim that pure reductionism is a valid approach for studying complex systems are those who have not had to think deeply about the problem. I have done my share of work in studying complex systems. And no, I am not advocating a pure reductionist approach here. But the fact you may have emergent phenomena in complex systems does not justify a sloppy approach. It is imperative to have all the basics right. -
Peter Hogarth at 07:48 AM on 11 July 2010Sea level rise is exaggerated
daniel at 14:18 PM on 10 July, 2010 To summarise: The original paper provides evidence used to suggest a relatively recent acceleration in sea level rise. The recent trend is taken from tide gauge data. This is accurate and errors small. We can take this as the "real" local relative sea level rise since 1856. The question is, what was the local sea level doing before 1856? Several data points derived from peat sediments are given where the dating of the sediment has uncertainties. Two more points are derived from heavy metal polution and pollen. A linear trend is fitted to these points which is less than half of the tide gauge trend, hence, acceleration. You argue that the longer term trend fitted to the sparser points may be hiding short term variations and other possible periods of acceleration. I argue that any variation is constrained by the error envelope of the points and the physical processes which might cause fast variations. I have provided a considerable body of evidence which supports this, but you have still focused on this data from this paper and provided a simple chart (but without any statistical analysis). I'll see about a chart with the actual tide data etc. -
Berényi Péter at 07:41 AM on 11 July 2010Hotties vs Frosties?
#43 chris at 02:00 AM on 10 July, 2010 there is a limit to how much we can productively "gnaw over" these [OHC issues] on a blog such as this Why? I have already shown you there is a problem with Murphy 2009.
It is inconsistent with the NODC OHC history reconstruction.
At least if both accounts are considered to be roughly correct, it follows between 1977 and 1990 about 4×1022 J of heat was sequestered in the deep ocean (below 700 m) without ever touching the upper layer. Then this process was interrupted, after that date all heat kept staying up.
In the meantime, as documented in Marsch 2000 Fig. 12. (a). there was no any abrupt change in total ocean overturning. The whole thing looks next to impossible.
The reason I keep gnawing over this issue is Google shows 152 references to this paper at the moment at skepticalscience.com. Therefore it must be pretty important from your point of view.
But until the strange discrepancy is explained, either Murphy 2009 or Levitus 2009 should be considered wrong (or both).
I do not want you to solve this particular problem, it is, as you say, a blog after all. Just acknowledge the problem exists. Even better, show us references to the peer reviewed literature where the problem is discussed. Or explain why is it ignored.
Until that time stop citing this paper as proof of warming, because with no further details supplied, the most probable explanation is that prior to mid 2003 (large scale deployment of ARGO) global OHC measurement is simply unreliable.
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John Russell at 06:44 AM on 11 July 2010How Jo Nova doesn't get past climate change
I looked at the comments on Jo Nova's site and got fed up after a few minutes of all the repetitive -- and meaningless -- "good on ya' Jo, you really showed them scientists a thing or too!" (or similar). I note that they have a voting system. If enough people give a comment the thumbs down, it's automatically removed. It's a great system -- for Jo -- it means virtually every comment in the thread is in support of her viewpoint. And it completely overwhelms any criticism. -
muoncounter at 06:27 AM on 11 July 2010Hotties vs Frosties?
"The hotties look at the data in the light of their models, and see something different. The point of difference is not that they see different things, it is the presence or absence of an underlying model of what they see." Unfortunately, the discussion often devolves into stylistic debates. There seem to be some who want to find models that fit data and others who suggest that models should tell data where to go. As an easy example -- Model: everyone knows human activity can't be causing global warming; Conclusion: any data that shows warming is invalid. But what happens when the discussion is merely "your data doesn't look like I think it should"? Or more insidiously, "your data doesn't look like my model results say it should"? I'm with Conan-Doyle on this: "It is a capital mistake to theorize before one has data. Insensibly, one begins to twist facts to suit theories, rather than theories to suit facts." -
Berényi Péter at 05:43 AM on 11 July 2010Hotties vs Frosties?
#8 perseus at 19:06 PM on 9 July, 2010 Despite Kuhn’s theories, the peer review procedure, a dedication to the truth, and sometimes quite fierce competition amongst scientists should prevent ‘Warmists’ becoming over-partisan Come on. There is a peer reviewed journal of Homeopathy on ScienceDirect. Does it make homeopathy a valid branch of science? Do you think those folks do not insist on being dedicated to truth? Is there no fierce competition in that field? The anonymous peer review process as it is practiced recently is an invention introduced after WWII in America then spread like wildfire all over the world. It was to ensure taxpayer's money went into sound research, not crap and also to keep up the prestige of popular journals. There was also a secret motive, to compensate for declining willingness of people to take personal responsibility and increasing reluctance of society to accept responsibility and conscience as assurances. Read some more on the subject. Michael Nielsen Three myths about scientific peer review January 8, 2009 at 2:18 pm · Filed under The future of science The New York Times THE DOCTOR'S WORLD When Peer Review Produces Unsound Science By LAWRENCE K. ALTMAN, M.D. Published: June 11, 2002 Unfortunately people all too often mix up the very different concepts being dedicated to truth vs. to a noble cause. -
Riccardo at 04:34 AM on 11 July 2010Sea level rise is exaggerated
daniel, i see your point, but you're comparing the values of sea level with sea level rise, i.e. the trend. It doesn't matter if the recent "high" resolution sea level data fall within the uncertainty of the sedimentary trend, what matters for Donnelly conclusions is that the two trends are significantly different. -
JMurphy at 04:31 AM on 11 July 2010Hotties vs Frosties?
johnd wrote : I wonder what odds Mr. Annan would consider a fair bet? Well, let's see : If Lindzen believes the earth will be cooling over the next 20 years (from 2005) and Annan believes it will continue to warm, then it's a straight bet of one man's money against the other's. Who needs odds...unless you're not confident of winning and want to put the other person off ? -
chris at 03:27 AM on 11 July 2010Hotties vs Frosties?
gallopingcamel at 15:21 PM on 10 July, 2010 "It is clear that increasing levels of CO2 in the atmosphere will cause warming. You folks are mostly with the IPCC that predicts a warming as high as +4.0 Kevin per doubling of CO2 concentration. IMHO +0.5 Kelvin is a much more likely figure. It is a shame that nobody is likely to be able to measure this quantity with any accuracy in my lifetime." That's an odd set of comments if you don't mind me saying so gallopingcamel. What evidence lends you to believe that climate sensitivty is so low? On the contrary, there seems to be a very large amount of evidence that supports a climate sensitivity between 2 - 4.5 oC (per doubling of [CO2]), which is quite well constrained at the low end (little likelihood of climate sensitivity below 2 oC[*]), but poorly constrained at the high end (scientifically poor basis for rejecting higher climate sensitivities). See for example Knutti and Hegerl’s recent review. R. Knutti and G. C. Hegerl (2008) The equilibrium sensitivity of the Earth's temperature to radiation changes Nature Geoscience 1, 735-743 [*] In fact it's increasingly difficult to see how climate sensitivity could be below around 2 oC (per doubling of [CO2]. For example, the Earth has warmed by around 0.8-0.9 oC since the middle of the 19th century, while [CO2] has risen from around 286 ppm then to 386 ppm now. A climate sensitivity of 2 oC should then give an equilibrium warming of: ln(386/286)*2/ln(2) = 0.85 oC We know that the Earth can't come instantly to equilibrium with the enhanced greenhouse forcing: we have a significant amount of warming to come from the greenhouse gas levels already attained. Likewise we know that some of the warming from the existing greenhouse gas levels has been offset by enhanced anthropogenic aerosols which are counteracting greenhouse induced warming. On the other hand some of the warming is due to non-CO2 sources (man-made methane, nitrous oxides, tropospheric ozone, black carbon). Non greenhouse gas contributions to this warming (solar, volcanic) are known to be small [**]. Overall if we've already had the warming expected from a 2 oC climate sensitivity, and we still have some warming still to come, and some of the warming has been offset by atmospheric aerosols, the likelihood of a climate sensitivty below 2 oC is really rather small (something extremely large must be missing from the known physics). What's your explanation gallopingcamel? [**] see for example: Knutti and Hegerl (see above), Murphy et al. (2009), Rind and Lean, 2008, Hansen et al (2005), etc. -
Sean A at 02:24 AM on 11 July 2010Hotties vs Frosties?
GC provides an example of the denialist tactics: exaggerate, spin, and disregard evidence. There is good evidence that indicate climate sensitivity for doubling CO2 is at least 1.5 and at most 5 degrees C, so 2 to 4 is a good estimate. This is a reasonable conclusion from looking at all the science that's been done on the subject (which is what IPCC does). Yet here Mr. GC says all us warmers believe it's on the high end (we don't), while he asserts (with no evidence) that the value is much lower than the low end of the reasonable estimate. Because even 2°C is not good news for human society. Yet somehow pure wishful thinking is supposed to trump what the accumulation of scientific evidence is telling us. As usual, Real Climate provides excellent guidance on this subject: The certainty of uncertainty "The bottom line is that climate sensitivity is uncertain, but we can pretty much rule out low values that would imply there is nothing to worry about. The possibility of high values will be much harder to rule out." -
daniel at 22:53 PM on 10 July 2010Sea level rise is exaggerated
Sorry Riccardo, to answer your question more directly, I don't think this particular comparison is valid at all. You also say that the tide gauge data has more deviation than 0.2mm/yr. Could you explain what you mean by that? Donnelly believes his long term trend may deviate overall by 0.2mm/yr over a ~550 year period. You can't compare that to the deviations in the tide gauge data and say that the tide gauge data is more noisy. There are no error limits placed on the short term linear trends discussed by Donnelly for the tide gauge data. You cannot compare visual non-quantified scatter to statistically determined error limits of a linear trend. Even if there were error limits on the proposed short term trends you should be able to see that I have shown that the tide gauge data can lie on a shallow long term trend of paleo data (samples 1-11) with a rate (1.2mm/yr) within the error limits proposed by Donnelly (1.0 +/- 0.2mm/yr).. -
DarkSkywise at 21:42 PM on 10 July 2010Hotties vs Frosties?
johnd #58: "That means he doesn't believe that warming is virtually certain to use IPCC terminology." Why? Somebody who's only prepared to put up £200 if you're willling to pay $10,000 is deliberately making the stakes too high, so the other will back down. "I'm sure, you're sure, but I'll let you run all the risks." I'm not a betting person, but even if I was, I wouldn't bet against somebody who wouldn't be willing to run any risks himself. ;) -
johnd at 19:40 PM on 10 July 2010Hotties vs Frosties?
John Russell at 18:35 PM, it is telling that Dr. Annan wasn't prepared to accept odds of 50-1. That means he doesn't believe that warming is virtually certain to use IPCC terminology. Based on IPCC defined likelihood of an outcome, the betting odds should be as follows:- "Virtually certainty" of warming occurring would roughly equate to odds of 100-1. "Extremely likely" of warming occurring, probability > 95%, would roughly equate to odds of 20-1. "Very likely", probability > 90% equates to roughly 10-1. I wonder what odds Mr. Annan would consider a fair bet? IPCC REPORT DEFINITIONS Likelihood of an outcome or result Virtually certain > 99% probability of occurrence Extremely likely > 95% Very likely > 90% Likely > 66% More likely than not > 50% Very unlikely < 10% Extremely unlikely < 5%. -
daniel at 19:26 PM on 10 July 2010Sea level rise is exaggerated
Riccardo, you have been absent from the discussion and it may pay for you to back track a little. I do not dispute any of the trends discussed or proposed by anyone I only dispute the argument made against me that significant deviations from the long term trend are impossible, highly unlikely or have been shown to not exist at Barn Island. Such short term deviant trends in the paleo data set would undermine any conclusiom of an unusual modern uptrend. I also have gone so far as to say that this is a good example of poor science swallowed by people who should know better but are blinded by fear of impending doom. -
CBDunkerson at 19:19 PM on 10 July 2010Hotties vs Frosties?
Baa Humbug #29, can you even NAME a scientist who says that AGW does not exist? Not that it might not be as bad as projected, but that it actually is not happening. I've seen a few, but in each case they've been pushing COMPLETE nonsense which flies in the face of basic physics (e.g. 'infrared radiation is magically prevented from traveling from a colder atmosphere down to a warmer planet'), mathematics (e.g. 'If we take a derivative to factor out the ongoing rise in temperatures then they correlate to natural process XYZ - ergo there is no ongoing rise'), and/or logic (e.g. 'CO2 levels go up and down all the time because 70 year old records taken outside factory districts show wild fluctuations'). Thus, if you think there ARE rational scientists who claim AGW is not happening at all I'd love to see their work. If not, then why can't we be done with a claim which NO ONE can provide support for and concentrate on the question of degree? Yes, I believe even there 'sceptics' are out on a VERY long limb, but they've still got SOME rational foundation for doubt. The biggest problem I see with their position is that IF they were right about all of the negative feedbacks in the climate system we ought to have seen those effects showing up by now. Yet MEASURED warming is on pace with 3 C per doubling of CO2 projections. -
John Russell at 18:35 PM on 10 July 2010Hotties vs Frosties?
Galloping Camel says, "...we could make some wagers." This is the crunch. If we 'warmists' are willing to take on the deniers directly by asking them to bet on outcomes, I think the reality would strike very quickly. And I can assure everyone it's a great way to shut someone up. The following is from an article in the Guardian "The bet is the latest in an increasingly popular field of scientific wagers, and comes after a string of climate change sceptics have refused challenges to back their controversial ideas with cash. Dr Annan first challenged Richard Lindzen, a meteorologist at the Massachusetts Institute of Technology who is dubious about the extent of human activity influencing the climate. Professor Lindzen had been willing to bet that global temperatures would drop over the next 20 years. No bet was agreed on that; Dr Annan said Prof Lindzen wanted odds of 50-1 against falling temperatures, so would win $10,000 if the Earth cooled but pay out only £200 if it warmed. Seven other prominent climate change sceptics also failed to agree betting terms. In May, during BBC Radio 4's Today programme, the environmental activist and Guardian columnist George Monbiot challenged Myron Ebell, a climate sceptic at the Competitive Enterprise Institute, in Washington DC, to a £5,000 bet. Mr Ebell declined, saying he had four children to put through university and did not want to take risks." So are we going to set up a really big fund to take on the deniers, with a handsome payout if they're proved right? I tell you; you won't see them for dust! -
Riccardo at 18:25 PM on 10 July 2010Sea level rise is exaggerated
daniel, the paper shows two data sets and draw conclusions explicitly based on both. It really does not matter who actually collected the data. The large error in the sedimentary data does not imply an equivalent large error in the trend. Indeed, the latter is 0.2 mm/yr and assuming a comparable error for the tide gauges data the difference in the trends is still significant. Or do you think it's not possible to compare two different data sets? -
gallopingcamel at 15:21 PM on 10 July 2010Hotties vs Frosties?
What a simple question. How could anyone be other than a "Hottie"? Thanks to the brainwashing I get on this site, you can count me as a "Hottie" even though my wife might disagree. It is clear that increasing levels of CO2 in the atmosphere will cause warming. You folks are mostly with the IPCC that predicts a warming as high as +4.0 Kevin per doubling of CO2 concentration. IMHO +0.5 Kelvin is a much more likely figure. It is a shame that nobody is likely to be able to measure this quantity with any accuracy in my lifetime. Otherwise we could make some wagers. -
Sean A at 14:43 PM on 10 July 2010Hotties vs Frosties?
What a ridiculous, naive post. Of course the fervent hotties will say, "But we've already done all the necessary work, and the weight of evidence is overwhelming." And the fervent frosties will say, "They haven't proved anything. They have failed to address this and this and this. Their results are meaningless". And there is validity to both of these points of view. The heart of the ridiculousness is in that paragraph. The denialists are arguing in good faith! Ha! The fallacy of false equivalence -
daniel at 14:18 PM on 10 July 2010Sea level rise is exaggerated
Peter Hogarth at 06:10 AM on 10 July, 2010 Pete I can't quite tell if this comment was supposed to be taken as a backdown on Donnelly 2004 or if you intend to argue further with a graph of your own. If a backdown I acknowledge that it would be of this paper and this paper alone. I cannot then use this to say that all of Donnelly's work is invalid. But I do have some personal doubts and I feel that this discussion should prompt those reading on to look again with a more critical eye as to what is published in both in climate literature and other disciplines. -
daniel at 14:06 PM on 10 July 2010Sea level rise is exaggerated
Riccardo at 02:19 AM on 10 July, 2010 "The behaviour of the data should be clear and we should also come to the same conclusions reported in Donnelly paper," Yes it's clear, a simple linear regression of the box centres shows that the ~1mm/yr trend extends up to 2000AD. Donnelly implies that the tide gauge data is unusually high compared to 1300-1850 AD. But it clearly isn't since we use the same methods to obtain a "modern" paleo sample and find no significant uptrend in the data. Donnelly's rate error limits are 0.8-1.2mm/yr over 1300-1850. The simple linear fit of all the paleo data up to 2000AD has a rate within these limits (no detail as to how the limits are acieved in the first place). Are you going to go on again and say that a significant uptrend has been detected by the tide gauge when there is no high certainty paleo data to compare it to? Please save your breathe (fingers). "Indeed, you (and Donnelly) get a statistically significant trend of 1.0 mm/yr before about 1850." Well actually I don't know what statistical analysis Donnelly has performed on his trendline since it's not mentioned. I have simply tried to reconstruct it using visual markers. Linear regression of the centres of sample boxes 4-11 gives a rate of ~1.1mm/yr. Donnelly was trying to marry up the earliest tide gauge trends with a proposed linear trend through 1300-1850. ".... including it rises the rate at 1.2 mm/yr but both R and chi2 decrease." Can you do some calculations to show this please and by how much they decrease? I won't have time over the next couple of days. You then go on to say that you agree the paleo data doesn't support a recent acceleration and that nobody was claiming otherwise or at least not the paleo data alone. But they were claiming samples 4-11 did and I am showing that inclusion of sample 1 undermines that conclusion. The short term tide gauge data compared to the much less certain, long term paleo data is invalid and I believe I have shown by inclusion of sample 1 in a simple linear regression that short term variance is easily achievable amongst samples 4-11. After agreeing with me on the insufficiency of the paleodata you then say that the conclusion is solid. (Throws hands up in air as a sign of frustration). I didn't make an error by claiming "by this paper" Donnelly only provides sedimentary data. Do you think he collected the tide gauge data? Do you still think the conclusion drawn from the comparison between the two data sets is valid? -
daniel at 11:35 AM on 10 July 2010Sea level rise is exaggerated
KR at 02:02 AM on 10 July, 2010 "You have the 11 paleo proxies with a slope of 1.023mm/year, the recent tide data with a slope of 2.4 or 2.8mm/year. And you then fit all the data with a slope of 1.2mm/year?" Please read the graph and post carefully. Samples 4-11 (that's 8 count em... 8, have you read the paper KR?) have the Donnelly linear fit (psst... it's not a least squares fit) of 1.023mm/yr. I used visual indicators/markers from the Donnelly graph (fig 2.) to construct it, it rounds to 1.0mm/yr. The dashed portion is extrapolated for comparisons to the other fitted lines etc. The least squares I have fitted to all paleo data produces a 1.2mm/yr average long term trend over the entire 700 years (thats a slope just inside Donnelly's error bars.... pennies dropping yet?) "Modern levels of SLR are KNOWN to be ~2.4 mm/year." That's nice..... "Donnelly's fit of ~1 +/- 0.2 mm/year average over the 1300/1900 period still holds." It holds to 2000AD....... look at the graph KR "Perhaps, just perhaps, there were major swings in SLR between the Donnelly sample points" I am suggesting short term swings that lie within the error bars. They are easily there, as I keep asking you.... read paper.... look at graph. The fact that a shallow linear trend extends up until 2000AD with tide gauge data that deviates from it but remains within the large error estimates of the most recent paleo sample is more than enough evidence to support my critique of this paper. Such deviations could have easily existed "(although as Peter Hogarth points out, lots of other data indicate that this is not the case, filling in the spaces between these linear fit samples)" He tried using Donnelly 2006 and failed miserably, sure there are other papers and I need to find time to read them but my first impression was not a good one. "There are certainly no physical phenomena that we know of that could cause reversible SLR changes on that order." I don't know what you mean by "reversible" (probably some exaggerated claim about the short term trends I'm suggesting involving unicorn plasmas). There seems to be alot that the climate science community doesn't fully understand about the hugely complex system known as planet earth. I don't really care if you have or haven't found drivers for ancient SLR swings. You can't claim they didn't exist from an amateur non least squares line fit! I'm not saying that recent SLR can't be 2.4mm/yr or that the long term trend isnt ~1mm/yr +/- 0.2mm/yr. Actually KR.... if you read carefully.... I'm saying its 1.2mm/yr..... :0 ..... wha!!!??? "And - if we had a 150 year change in SLR of this magnitude in the previous 1000 years, the paleo data points wouldn't all be on the fit line!" I am moved to laugh... You mean like the centres of sample boxes 8, 11 and 10? "I suspect Peter will have something to say about this as well..." Yes that's right KR, if it wasn't for him we'd barely have a discussion. Why don't you let him do the talkin while you do some readin, not skimming. -
johnd at 10:01 AM on 10 July 2010Tai Chi Temperature Reconstructions
Peter Hogarth at 05:45 AM, tree growth, indeed any plant growth, is subject to a number of different conditions all being in place, the final result depending on how well balanced the combination is at any given period of time. Temperature is but one of those conditions. I think that once all the other factors have been adequately accounted for, then what is left over could reasonably be attributed to temperature. However the understanding of all the other factors is far from complete, the science is not settled, the understanding for some of the factors it is almost certainly less than adequate. It is difficult enough in controlled circumstances such as occurs in agriculture or in plantation forestry where soil and tissue testing and ongoing monitoring of local conditions is possible, let alone in some remote natural environment, even in real time. Trying then to establish how that combination of factors all came together at some distant point in time requires a lot more information then merely the width of the growth rings, information, some of which I am not convinced is even available. The fertilisation effects of CO2 have been known for over a century, trials in more recent times show that the effect is not uniform across all species, and is subject to other local contributing factors. Thus this contributing, and perhaps significant factor can only be adequately allowed for once it has been studied on the trees that are being used to correlate growth with temperature. This is vitally important because both CO2 and temperature are claimed to be directly related and thus it is necessary to separate and allocate each of the inputs. Much the same applies to all other inputs be they positive or negative factors. One additional factor that I have become aware during my reading on the subject of tree ring growth temperature relationship, is that the selection of trees to measure is far from random. It relies not only the selection of species, but the selection of individual trees whose growth is considered to faithfully represent a robust relationship between growth and temperature. This is referred to in Buntgen 2008. "Tree-ring width chronologies from 40 larch and 24 spruce sites were selected based on their correlation with early (1864–1933) instrumental temperatures to assess their ability of tracking recent (1934–2003) temperature variations." That may inspire confidence in some, but does the opposite for me. To sum up, I have always understood that temperature is an influence on all forms of plant, and animal, growth. However I have also been equally aware of all the other essential factors, thus once temperature reconstructions using tree growth rings started to be given prominence, I began having reservations as there didn't appear to be adequate understanding of the all the other factors. The emergence of the divergence problem was, and still is justification for such reservations. If it cannot be accounted for during recent times with all the access to high quality data and the ability to study the contributing factors in real time, what faith can one have that the same factors have been allowed for in the historical reconstructions. It is our individual acceptance of that which I think puts us at cross purposes, if we are that is, on the matter of the divergence problem. -
DarkSkywise at 09:58 AM on 10 July 2010Hotties vs Frosties?
villabolo #51: Online polls... humbug! (Not you, Baa Humbug. You aren't a poll.) :P We've recently had elections in the Netherlands and there were online polls showing 70-80% of the votes going to the anti-immigrant Freedom Party (who also believe AGW is a conspiracy to raise taxes, globally orchestrated by the dutch Labour Party - no, I'm not making this up), with even people vehemenly believing those figures. Of course, in the end, it didn't happen quite that way. Online polls really just show one thing only: people voting on online polls. Which, fortunately, is not the same as "our side slipping". ;) -
kdkd at 09:00 AM on 10 July 2010Hotties vs Frosties?
BP #40 Your argument is rather weird. You appear to be claiming that reductionism is the only valid approach to scientific method. As you can see here reductionism becomes much less useful in situations with "higher amounts of complexity, including culture, neural networks, ecosystems, and other systems formed from assemblies of large numbers of interacting components". You'll find a large literature refuting your implied assertion that reductionism is the only valid approach if you look for it. The only people who claim that pure reductionism is a valid approach for studying complex systems are those who have not had to think deeply about the problem. -
villabolo at 08:24 AM on 10 July 2010Hotties vs Frosties?
John, I beg to differ with you. I have observed and posted on WUWT and one of my first experiences was to have a poster say that if I could not correctly spell the name of another poster (Anna vs Ana) then I wasn't likely to have any understanding on the subject matter. While this was the worse example, there were plenty others who were nasty in proportion to the civil ones. Also the major difference between the rudeness of "Skeptic" vs "AGW's" can be very easily spotted on the commentary section of any site that has an article on GW or even You Tube. In other sites or in You Tube, whenever a video is posted on either side of the issue, the "Skeptics" come out in full force, overwhelming the number on "AGW's". And the majority of them range from rude to extremely rude. Take a look John, and you'll find that there is NO EQUIVALENCY whatsoever. By the way, MSNBC is taking a poll of people asking for their opinion on whether the British Panel's exoneration of scientists on "Climate Gate". Anthony Watts is on the warpath asking his readers to vote. Our side has been steadily slipping. From 42% in our favor and 58% against, yesterday to 39.1%<60.9% as of this moment. Some of you may want to put in your two cents worth. Sorry for the long link. http://msnbc.newsvine.com/_question/2010/07/07/4630892-are-you-satisfied-with-the-british-panels-conclusion-that-while-climategate-scientists-were-not-always-forthcoming-their-science-was-sound?pc=20&sp=180&threadId=1004983&commentId=15443603#c15443603 -
Peter Hogarth at 06:10 AM on 10 July 2010Sea level rise is exaggerated
daniel at 19:25 PM on 9 July, 2010 Daniel, thanks for the chart. It would take me a little longer to enter the data and do one with error envelopes and the tide gauge data, but I think we now get a better explanation of why this misunderstanding has rolled on... -
KR at 05:56 AM on 10 July 2010Sea level rise is exaggerated
johnd - sorry about that; I really need to get off this cold medicine! That should be a reference to daniel. -
NickD at 05:54 AM on 10 July 2010Hotties vs Frosties?
"...would these green folks advocate going against Nature to artificially cool the Earth?" So if I reduce the amount of fossil fuels I use,and granting your hypothetical to be true, how exactly am I "artificially" cooling the Earth? Also, if I have an iced latte, am I helping getting rid of the waste heat? -
Peter Hogarth at 05:45 AM on 10 July 2010Tai Chi Temperature Reconstructions
johnd at 03:43 AM on 10 July, 2010 John, I think we are at cross purposes on Divergance Problem. I have not missed the purpose of this paper or the others, I'm fairly familiar with them. I have not denied the DP exists, just tried to point out that it is an an effect most likely unrelated to temperature, ie the validity of tree rings as temperature proxies, away from significant SO2 influence and where other factors such as moisture are accounted for, is solid, as in your comment 51, as in Buntgen. Are we agreeing on this? The correlation of growth with instrumental temperature records for the Buntgen and other studies I referenced in my first comment is compelling and credible (or I think so). The correlation with CO2 less so, though again this is a recognised factor, and I have papers on this also. Have a look at the ones supplied so far, they contain a lot of pertinent information. Your suggestion of competing SO2 and CO2 is opinion. I don't dismiss it, but without evidence, I take it as such. The seasonal and year to year growth patterns and seasonal temperature are relevant evidence here, as correlation is seen at this level. In terms of Sulphur absorption you should read the references I supplied. The tree ring growth, measured SO2 atmospheric levels, and sulphur levels in the woody growth itself are direct evidence concerning your "extended residence time" suggestion. SO2 is one potential explanation for DP, based on the data available, the references I cited cover this, and Buntgen does (briefly). One other specific factor mentioned is decreasing moisture (climatic). It may well be combinations of several factors which are challenging to disentangle, but the experts would not "dismiss" any of them, and I don't either. -
johnd at 03:59 AM on 10 July 2010Sea level rise is exaggerated
KR at 02:02 AM on 10 July, 2010 johnd - Thank you for the chart. - ????????????????????????? -
johnd at 03:43 AM on 10 July 2010Tai Chi Temperature Reconstructions
Peter Hogarth at 22:01 PM on 9 July, 2010, I think you missed the overall findings of Buntgen 2008 by focusing on certain aspects only. First the study acknowledges that the DP exists right at the beginning:- "Abstract Evidence for reduced sensitivity of tree growth to temperature has been reported from multiple forests along the high northern latitudes. This alleged circumpolar phenomenon described the apparent inability of temperature-sensitive tree-ring width and density chronologies to parallel increasing instrumental temperature measurements since the mid-20th century." Secondly they acknowledged the concerns such evidence brings:- "If DP is widespread and the result of climatic forcing, the overall reliability of tree-ring-based temperature reconstructions should be questioned." It appears to me that what the study set out to achieve was to determine whether the DP is climate related or not. My understanding of the results is that from the data they analysed, they found that there was no DP evident in the trees they studied. Thus my interpretation of their conclusions is not that the DP is non-existent, but that it most likely is not climate related. Whether or not it is widespread cannot be determined simply by what has been the case at one study site, but it certainly has been found at a number of sites as mentioned in the abstract, thus I believe it is real. However, it appears that the Buntgen 2008 study didn't consider one possibility, that being that the consistent growth they found may be the nett result of two opposing factors, namely CO2 and SO2. It didn't even mention what the growth response to rising CO2 levels was to be expected from the trees under study. These are matters that I believe have to be accounted for before any such study can be seen as complete. Thus I don't believe that Buntgen 2008 has really advanced the understanding of the DP at all, hence my comment of it being of limited use. Therefore what causes the DP? Something obviously does, and apparently that something still hasn't been identified. I suggested SO2. You appear to both acknowledge the effects of SO2 and dismiss it because it is short lived. What you are missing is that once the SO2 has been absorbed by the vegetation, the sulphur so released is deposited to the soil below where it remains. Where "acid rain" occurred in farming areas, the sulphur was stripped from the soil along with the other nutrients that were taken up by the plants and animals that were being farmed and initially the extra sulphur was actually beneficial. When SO2 emissions were reduced, farmers were forced to add additional sulphur to their land in order to maintain production. Such stripping of sulphur from the forests does not occur unless logging takes place, and thus if the sulphur has built up to the extent it has effected tree growth, it will remain there for an extended time. I think any study that tries to tie tree growth to any climatic indicator must firstly reference any research that examines how the trees under study respond to changing CO2 levels, especially to levels less than the current ambient where historical growth patterns are being analysed, and secondly other relevant "pollutants" both from anthropogenic and natural sources especially where there may be an accumulation over time. -
RSVP at 03:17 AM on 10 July 2010Hotties vs Frosties?
According to this article, Hotties are green. But if global warming (hypothetically) proved to be due to Nature, would these green folks advocate going against Nature to artificially cool the Earth? Meanwhile, all those lattes are generating waste heat which of course has nothing to do with global warming.Response: If global warming proved to be due to nature, then all our CO2 emissions are not causing warming. Set aside for the moment the question of how all the trapped heat directly observed by satellites and surface measurements is not causing warming. If we believe CO2 is not causing warming, then reducing our CO2 emissions will have a minimal effect. You can't say adding CO2 has no effect but not adding it will have an effect. -
Hotties vs Frosties?
BP, This is a blog, we aren't performing the scientific method here, that's for practicing scientists out in the field producing peer-reviewed research. We are reviewing the evidence that is produced by that science to gain a broad understanding of our world and where we are headed. This is inherently a "big picture" approach. To abandon this approach is to say that science can make no broad statements about how the world works; it is reduced to a meaningless excercise in data collection. -
apeescape at 02:33 AM on 10 July 2010Hotties vs Frosties?
We need to find a label for the people who average out the opinions of the frosties and hotties. Is "air conditioneries" apropos? :) "The frosties look at the data without any underlying model, and see no trend. The hotties look at the data in the light of their models, and see something different. The point of difference is not that they see different things, it is the presence or absence of an underlying model of what they see." This passage could be taken as: frosties are unbiased, or frosties are unscientific. I think most people that get serious about this issue has a model in their heads. I'm not sure why the hotties (or the frosties) are assumed to not look at "the other side."
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