date: Thu Jul 15 16:25:46 2004 from: Phil Jones subject: Paleo data to: hegerl@duke.edu Dear All, Gabi, I was answering one of the skeptics yesterday. The answer is below. To see the original there is a pdf link near the end. No need to read, but Tom might like to see it. Susan Solomon was here on Tuesday getting an honorary degree. She says we will have to deal with all these crackpots in the IPCC ! There will be a number in the atmos obs, paleo and in your chapter I suspect - will likely be the hardest bits to write. Still awaiting from you a revised draft to comment for IDAG. As for your email, there was some press activity related to this skeptic below, but managed to talk the BBC out of doing anything. The Moscow meeting sounds to have been really bad. I would have guessed as much. As for your question, perhaps you can put it to me with some more text as I don't understand it fully. Do you have a diagram? Do you scale by simple multiplying or by regression (with a constant) and over what period? Not sure I see the distinction of variance and amplitude you and Myles are working on. Maybe show me what both methods do the paleo series. I reckon that Hans' long run has too big a volcanic signal. All models do. There should be a seasonal cycle in the response, but I've never seen one in a model. I guess I'm saying that assuming a model is the answer may not be entirely the right way to go. I'm not going to Paris. Susan was asking me why I've not been to any IPCC meeting yet. I said I didn't know why I ought to go. The Paris one is the first I've really thought about, but even there I've not done much in the area. Cheers Phil Dear Timo, I can fully understand why Mike Mann doesn't have email contact with you. I have read David Legates' piece on the NCPA web site and there is so much wrong with it, I don't know whether I should attempt to respond. I will, but I'll be brief. I don't want it to seem like nitpicking, but David should get his facts right. He should have read the papers properly and noted their dates and years. He should put up an apology and he should back up his text with some facts/details and not just statements saying the record is unreliable and can't be reproduced. I will go through a few points and will not respond any more unless David issues an apology. Surely, if you want people to believe your point of view you should get the facts right. Keynes changed his opinion when the facts changed, but I'm sure he first checked that the facts were right ! 1. The Figure is from the IPCC Report of 2001. Fact. 2. The GRL paper by Mann and Jones was written in 2003. Fact 3. The GRL paper was not an update of what IPCC reported, nor was it an update of what IPCC used in 2001 (namely the Mann et al papers in 1998/1999). Fact 4. The GRL paper had a clearly different intention as stated in the paper. Fact 5. So, the curve from the GRL 2003 paper was not used in the 2001 IPCC report. Fact - it couldn't have been. 6. The McIntyre and McKittrick paper in 2003 in Energy and Environment didn't contend that Mann and Jones unjustifiably truncated and extrapolated trends or data. Fact - it couldn't have because it was printed before the Mann and Jones 2003 paper in GRL came out. 7. The Mann and Jones 2003 paper didn't unjustifiably truncate or extrapolate trends or data in any of the series used. Fact - I have all the series. 8. The Mann and Jones 2003 paper uses series from 2 ice boreholes in Greenland. Fact - we digitized the series from the original papers. 9. Land borehole data are not used in Mann and Jones 2003. Fact - we stated in the paper we wanted to only use series that correlate with instrumental records. If someone can tell me how to correlate a series with two values (one for 2000 and one for 1900) then please do. The 2003 paper's aim was to develop an annual-timescale series. Borehole series are not amenable for this. There is a paper by Huang (2004) in a recent GRL where a combination is attempted, but an assumption is made that boreholes give one timescale, conventional another. 10. Esper et al (2004) argue that our tree-ring series are over standardised and have lost low frequency. The techniques Esper et al use were developed here at CRU (by my colleague Keith Briffa). Fact - Jan Esper often seems to forget this. If you note the series Mann and Jones (2003) use, you will see we were very careful with standardization. All the discussion about trees and the loss of low-frequency variation began in CRU. Fact. 11. None of the series we use are based on too few trees. A more relevant fact is that many of Esper et al are in the earliest years. It is necessary to go back and read the papers, back to the first in the early 1990s. 12. We do not correlate temperature trends with tree age. Fact - this just shows how ridiculous some of the sentences in the Legates' piece are. Why would we want to do this. 13. The borehole retraction by Mann and Rutherford is about 0.1 deg C. Fact - read the retraction. 14. The trend over the 20th century in the Figure and in the instrumental data. IPCC quotes 0.6 deg C over the 1901-2000 period. Fact - but Legates is eyeballing the curve to get 0.95 deg C. A figure isn't given in Mann and Jones (2003). Take it from me the trend is about the same as the instrumental record. 15. The series in Mann and Jones (2003) is a simple average of all the constituent series. Fact. Averaging is straightforward, we also experimented with various weights. I wouldn't call averaging a statistical technique, but I suppose a weighted mean could be referred to as a statistic. Throughout the whole piece though Legates appears to me be referring back to Mann et al paper in 1998. I may be wrong here, and I apologize if I am. I only read continued reference to Mann and Jones (2003). 16. Isn't it a good idea to base the use of proxy records on how they match instrumental records ! Am I missing something here? When did anyone decide that proxy records could be assumed to match something else? They are proxy records - past climate proxies, in this case for temperature. If a record is a proxy for temperature, then to my mind it should have some agreement with an instrumental record. This is a basic fundamental of paleoclimatology. 17. The instrumental record has not been considered up to now - although you accepted the IPCC warming of 0.6 deg C earlier. I could go into more detail here but won't as it is another issue. 18. Mann and Jones (2003) had a method for estimating uncertainty back in time. When I say we had a method, I mean we used numbers to estimate it. Legates says based on his preliminary analysis it is twice as large - based on what? Clearly based on someone who believed we were wrong to base our use of proxy records solely on how well they matched instrumental temperature data ! 19. Mann and Jones (2003) make no such claim that all change over the last 2000 years occurred in the 20th century. Fact, we don't. We have stated in other articles that the MWP and LIA are simplistic interpretations of the past and all paleoclimatologists would be better referring to the past using calendar dates. If the widely accepted MWP and LIA were as clear as Legates seems to think, why are paleoclimatologists bothering to collect more data? 20. We do claim that the late-20th century is the warmest period of the millennium. Fact. We also claim that the 1990s are the warmest decade and that 1998 is the warmest year. We don't make those claims in the 2003 paper. As I said at the beginning I could go into more detail. I have only done to put the record straight, not to enter into any debate. Regards Phil At 11:43 14/07/2004 +0300, Timo Hämeranta wrote: Dear Phil Jones, for years we have discussed and debated with scientific courtesy, and agreed to disagree when disagreed. Now, Id like to learn your comments on the following brief analysis Legates, David R., 2004. Breaking the Hockey StickNational Center for Policy Analysis Brief Analysis No. 478, July 12, 2004, online <[1]http://www.ncpa.org/pub/ba/ba478/> and pfd <[2]http://www.ncpa.org/pub/ba/ba478/ba478.pdf> In the straightforward American way David ends his analysis as follows: The Hockey Stick is Broken. Mann wrote the part of the IPCC Third Assessment Report (2001) that proclaims that nearly all of the climate change seen during the last two millennia occurred during the 20th century and that it is due to human activities. The report contends that industrialization put carbon dioxide and other greenhouse gases into the atmosphere, leading to increasing global air temperatures. Furthermore, it claims that the 1990s were the warmest decade of the last two millennia and 1998 was the warmest year. But a review of the data shows that these claims are untenable. Manns research is clearly the outlier and does not fit with the overwhelming evidence of widespread global warming and cooling within the previous two millennia. Consider that if 1) the amount of uncertainty is doubled (an appropriate representation of the sheath), 2) appropriate 20th century increases in observed air temperature are applied (a correct representation of the blade), or 3) the period from A.D. 200 to 1900 correctly reproduces millennial-scale variability (a reliable representation of the shaft), then one can have no confidence in the claim that the 1990s are the warmest decade of the last two millennia. The assertions of Mann and his colleagues and, consequently, the IPCC are open to question if even one component of their temperature reconstruction is in error, let alone all three! Further, one very important concern (to us all, I do hope!) is that David also is unable to reproduce the results you received. We have already e.g. McIntyre & McKitrick on MBM98 and Soon on IPCC TAR. David correctly states that reproducibility is a hallmark of scientific inquiry. Unfortunately, Michael E. Mann refuses to communicate. Dear Phil, your comments are again greatly appreciated. All the best Timo xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Timo Hämeranta, LL.M. Moderator, Climatesceptics Martinlaaksontie 42 B 9 01620 Vantaa Finland, Member State of the European Union Moderator: timohame@yahoo.co.uk Private: timo.hameranta@pp.inet.fi Home page: [3]http://personal.inet.fi/koti/hameranta/climate.htm Moderator of the discussion group "Sceptical Climate Science" [4]http://groups.yahoo.com/group/climatesceptics "To dwell only on horror scenarios of the future shows only a lack of imagination". (Kari Enqvist) "If the facts change, I'll change my opinion. What do you do, Sir" (John Maynard Keynes) "As long as we are unable to explain the evident inconsistencies that fly in the face of climate alarmism, attempts to associate scientific scepticism with Holocaust denial can only be regarded as political incitement." (Benny J. Peiser, CCNet January 30, 2003) xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Prof. Phil Jones Climatic Research Unit Telephone +44 (0) 1603 592090 School of Environmental Sciences Fax +44 (0) 1603 507784 University of East Anglia Norwich Email p.jones@uea.ac.uk NR4 7TJ UK ---------------------------------------------------------------------------- Prof. Phil Jones Climatic Research Unit Telephone +44 (0) 1603 592090 School of Environmental Sciences Fax +44 (0) 1603 507784 University of East Anglia Norwich Email p.jones@uea.ac.uk NR4 7TJ UK ----------------------------------------------------------------------------