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Comments 51 to 55 out of 55:

51. scaddenp at 11:08 AM on 3 April, 2012
    Note by the way, that in Realclimate's "doing it yourself" article, it pointed to M&W excellent collection of code and data which allows you to run "no Tiljander", or "no tree ring" etc runs yourself. I'm lost to see Brandon's point about these being key to signal. Gavin notes "it's worth pointing out that validation for the no-dendro/no-Tilj is quite sensitive to the required significance, for EIV NH Land+Ocean it goes back to 1500 for 95%, but 1300 for 94% and 1100 AD for 90% "
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52. Tom Curtis at 14:58 PM on 3 April, 2012
    shoyemore @49, based on your example, the controversial part of Lu et al's finding should have been stated as:

    "Our most recent crystals suggest a warming relative to the LIA in the last century, possibly as part of the regional recent rapid warming, but this climatic signature is not yet as extreme in nature as the MWPMCA . The resolution of our record is insufficient to constrain the ages of these climatic oscillationsvariations in the Southern hemisphere relative to their expression in the Northern hemisphere, but our ikaite record builds the case that the oscillationsimpacts of the MWPMCA and LIA are global in their extent and their impact reaches as far South ashad temperature variations had the same sign in the Antarctic Peninsula as in Europe, while prior studies in the AP region have had mixed results."

    (deletions struck through, additions in bold, quoted from WUWT) The point here is that as originally written, whether intended or not, the amended passage carried the implication of increased warmth in all regions in the MCA relative to the early 20th century. That implication just cannot be sustained by the evidence presented. Eleven temperature datums at just one location cannot establish the prima facie case for global warmth that would be needed for that statement to be valid without severe qualification. (Note: if anybody thinks I am contradicting my earlier claims, they need to revise their understanding of just how weak is the relationship, "is evidence of".) To see this clearly, consider the actual evidence presented in the paper: The ikaite proxies are the eleven dots shown against climate proxies from the nearby region, two from the eastern Antarctic Peninsular, one from the western Antarctic Peninsula, and one from East Antarctica. Note that the temperature equivalence is inverted for part (a) compared to the other three. The original caption reads:

    "Fig. 6. δ18Ohydra profile (in green) plotted with other climate records, assuming sedimentation rate of 0.96 cm/yr and ikaite formation depth of 3.04±0.57 m. δ18Ohydra variability among different crystals found at the same depth is about±0.33‰. A–B: Magnetic susceptibility and TOC of JPC2 are plotted against age. C: SST at Palmer Deep, the line represents a five-point moving average (Shevenell et al., 2011). D: δ18OEPICA data are smoothed by a ten-point moving average. E: Timing of climatic events summarized for the AP region and citations (1 — Pudsey and Evans (2001); 2 — Jones et al. (2000); 3 — Brachfeld et al. (2003); 4 — Khim et al. (2002); 5 — Hall et al. (2010); 6 — Domack et al. (1995); 7 — Liu et al. (2005))."

    (quoted from WUWT) The dates of the eleven samples are approximately: Modern Era: 1920, 1885, LIA: 1630, MCA: 1465, 1325, 1150, Other: 855, 770, 665, 370, 215 All dates are plus or minus 60 years. Further, I have assumed the "present" is 2010 for calculating years before present. By convention it is often 1950, but may be as late as 2012. In any event, it is very clear that "our most recent crystals" whose "climactic signature is not yet as extreme in nature as the MWP actually comes from the late 19th century to middle twentieth century, and is not representative of late twentieth century temperatures. So the evidence in the study neither supports nor contradicts the claim that Antarctic Peninsular temperatures in the MCA where greater than they are in the late 20th and early 21st century. It has no comparable temperature proxy in that period to make the comparison.
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    Moderator Response: [DB] Note that the strike hash tag command is currently not operative.
53. Tom Curtis at 15:00 PM on 3 April, 2012
    scaddenp @51, but didn't you know? A significance of 94% means the evidence does not exist, and even supports the contrary hypothesis if you don't like what the evidence appears to say. Deniers are quite aware of this fundamental principle, and use it all the time. / sarc
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54. muoncounter at 09:52 AM on 12 April, 2012
    Update from Syracuse available here: “It is difficult for the lay public to make informed decisions about contentious issues — particularly those concerning climate change, conservation and preservation — which require objective, scientific research and discovery when news reporters fail in their duty to write accurately about the science behind the issues.” Failure to write accurately about science is a job requirement in some camps.
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55. Alex The Seal at 21:28 PM on 10 May, 2012
    Excellent study on the European MWP Here "A gridded reconstruction of spring-summer temperature was produced for Europe based on tree-rings, documentaries, pollen assemblages and ice cores. The majority of proxy series have an annual resolution. For a better inference of long-term climate variation, they were completed by low-resolution data (decadal or more), mostly on pollen and ice-core data." Using a number of different proxies they mapped temperature anomalies giving a detailed regional view of the warming.
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