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Gergis et. al 2012: The Latest Broken Hockey Stick http://www.envirolink.org/forum/viewtopic.php?f=3&t=18778 |
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Author: | Ockham [ Tue Oct 23, 2012 12:25 am ] |
Post subject: | Re: Gergis et. al 2012: The Latest Broken Hockey Stick |
"Quote: This video actually shows the interpretation of a graph by CO2 Science in some detail: "Why would anyone want to use proxy measurements instead of direct measurements when the direct measurements are available?" How did your BS meter miss that? Maybe you could defend the CO2 Science interpretations since Snowy clearly gas not been willing to attempt to do so." Wayne, I see we crossed posts. You tactfully avoid the question. The video shows a number of different reconstructions with thermometer data pasted on the end of the reconstructions. I interpret that as more for illustrative purposes. But, please do explain, in your own words, how that has any validity in drawing the conclusion that the CWP is warmer than the MWP? You say, 'Why would anyone want to use proxy measurements if direct measurements are available?' The reconstructions start with proxy data and should end with proxy data. If we had thermometer data 1000 years ago, I'm sure we would compare it to thermometer data today. But we don't, so please explain to me why anybody would compare apples to oranges and be taken seriously? These are different data sets with different precision and granularity, but presented and interpreted as one. As a scientist, you should know better and you wouldn't accept such sloppy arguments from skeptics. Will I have to ask you again? Ock |
Author: | Iowanic [ Tue Oct 23, 2012 2:48 am ] |
Post subject: | Re: Gergis et. al 2012: The Latest Broken Hockey Stick |
http://wottsupwiththat.com/ I've kept tabs on the wattsup site for some monthes. I take everything brought up there with about 5 pounds of salt. The wottsupwiththat grants some insight into what's going on there for those who are wondering... |
Author: | warmair [ Tue Oct 23, 2012 2:57 am ] |
Post subject: | Re: Gergis et. al 2012: The Latest Broken Hockey Stick |
Ock The question is is can we prove that globally the MWP was warmer than CWP ? You appear to be claiming that lack of proof means that it must have been warmer during the MWP by invoking the null hypothesis. It is probable that today is globally warmer than the MWP (dark blue 1000-1991): P.D. Jones, K.R. Briffa, T.P. Barnett, and S.F.B. Tett (1998). "High-resolution Palaeoclimatic Records for the last Millennium: Interpretation, Integration and Comparison with General Circulation Model Control-run Temperatures". The Holocene 8: 455-471. doi:10.1191/095968398667194956 (blue 1000-1980): M.E. Mann, R.S. Bradley, and M.K. Hughes (1999). "Northern Hemisphere Temperatures During the Past Millennium: Inferences, Uncertainties, and Limitations". Geophysical Research Letters 26 (6): 759-762. (light blue 1000-1965): Crowley and Lowery (2000). "Northern Hemisphere Temperature Reconstruction". Ambio 29: 51-54. Modified as published in Crowley (2000). "Causes of Climate Change Over the Past 1000 Years". Science 289: 270-277. doi:10.1126/science.289.5477.270 (lightest blue 1402-1960): K.R. Briffa, T.J. Osborn, F.H. Schweingruber, I.C. Harris, P.D. Jones, S.G. Shiyatov, S.G. and E.A. Vaganov (2001). "Low-frequency temperature variations from a northern tree-ring density network". J. Geophys. Res. 106: 2929-2941. (light turquoise 831-1992): J. Esper, E.R. Cook, and F.H. Schweingruber (2002). "Low-Frequency Signals in Long Tree-Ring Chronologies for Reconstructing Past Temperature Variability". Science 295 (5563): 2250-2253. doi:10.1126/science.1066208. (green 200-1980): M.E. Mann and P.D. Jones (2003). "Global Surface Temperatures over the Past Two Millennia". Geophysical Research Letters 30 (15): 1820. doi:10.1029/2003GL017814. (yellow 200-1995): P.D. Jones and M.E. Mann (2004). "Climate Over Past Millennia". Reviews of Geophysics 42: RG2002. doi:10.1029/2003RG000143 (orange 1500-1980): S. Huang (2004). "Merging Information from Different Resources for New Insights into Climate Change in the Past and Future". Geophys. Res Lett. 31: L13205. doi:10.1029/2004GL019781 (red 1-1979): A. Moberg, D.M. Sonechkin, K. Holmgren, N.M. Datsenko and W. Karlén (2005). "Highly variable Northern Hemisphere temperatures reconstructed from low- and high-resolution proxy data". nature 443: 613-617. doi:10.1038/nature03265 (dark red 1600-1990): J.H. Oerlemans (2005). "Extracting a Climate Signal from 169 Glacier Records". Science 308: 675-677. doi:10.1126/science.1107046 (black 1856-2004): Instrumental data was jointly compiled by the w:Climatic Research Unit and the UK Meteorological Office Hadley Centre. Global Annual Average data set TaveGL2v [2] was used. |
Author: | Wayne Stollings [ Tue Oct 23, 2012 11:39 am ] |
Post subject: | Re: Gergis et. al 2012: The Latest Broken Hockey Stick |
Author: | Wayne Stollings [ Tue Oct 23, 2012 11:55 am ] |
Post subject: | Re: Gergis et. al 2012: The Latest Broken Hockey Stick |
Author: | Snowy123 [ Sat Nov 03, 2012 7:48 pm ] |
Post subject: | Re: Gergis et. al 2012: The Latest Broken Hockey Stick |
Author: | Snowy123 [ Sat Nov 03, 2012 7:49 pm ] |
Post subject: | Re: Gergis et. al 2012: The Latest Broken Hockey Stick |
By the way, the Gergis et al. paper has been retracted because of errors found within the dataset by skeptics. Kudos to McIntyre and skepticism in general. |
Author: | Snowy123 [ Sat Nov 03, 2012 7:50 pm ] |
Post subject: | Re: Gergis et. al 2012: The Latest Broken Hockey Stick |
Author: | Wayne Stollings [ Sat Nov 03, 2012 8:22 pm ] |
Post subject: | Re: Gergis et. al 2012: The Latest Broken Hockey Stick |
Author: | Wayne Stollings [ Sat Nov 03, 2012 8:26 pm ] |
Post subject: | Re: Gergis et. al 2012: The Latest Broken Hockey Stick |
Author: | Snowy123 [ Sun Nov 04, 2012 9:59 am ] |
Post subject: | Re: Gergis et. al 2012: The Latest Broken Hockey Stick |
Author: | Snowy123 [ Sun Nov 04, 2012 10:02 am ] |
Post subject: | Re: Gergis et. al 2012: The Latest Broken Hockey Stick |
I disagree that the data doesn't line up with each other. The MWP is showing up at around 1000 AD on one of your charts, wheras on another it has shown up from 1050 AD-1300 AD. Assuming that there is room for error with these proxies (which there always is) then they don't disagree with each other as much as you claim they do. |
Author: | Johhny Electriglide [ Sun Nov 04, 2012 1:23 pm ] |
Post subject: | Re: Gergis et. al 2012: The Latest Broken Hockey Stick |
Author: | Wayne Stollings [ Sun Nov 04, 2012 2:34 pm ] |
Post subject: | Re: Gergis et. al 2012: The Latest Broken Hockey Stick |
Author: | Wayne Stollings [ Sun Nov 04, 2012 2:48 pm ] |
Post subject: | Re: Gergis et. al 2012: The Latest Broken Hockey Stick |
http://www.clim-past.net/8/765/2012/cp-8-765-2012.pdf The corresponding 95% confidence intervals have widths of 0.6 (two millennia long reconstruction) and 0.4 C (500-yr long reconstruction) for 50-yr smoothed values, thereby showing that the residual noise-variance is relatively small compared to the reconstructed low-frequency signal. Our main conclusions are as follows. – Our reconstructions indicate – in agreement with the results of Moberg et al. (2005); Ljungqvist (2010), and Loehle and McCulloch (2008) – that the first millennium AD was generally significantly warmer than the second millennium AD. The 17th century was the coldest century during the last two millennia and most of the LIA seems to have been colder than during the Dark Age Cold Period ca. 300–800 AD. In general, our LOC reconstructions show larger low-frequency variability than previous reconstructions. – Our two-millennia long reconstruction has a well defined peak in the period 950–1050AD with a maximum temperature anomaly of 0.6 C. The timing of the peak of the MWP in our reconstruction is in agreement with the reconstructions of Esper et al. (2002a) and Ljungqvist (2010). The reconstructions of Mann et al. (2008, 2009) show a longer peak warming covering the whole period 950–1100 AD, and the reconstruction of Moberg et al. (2005) shows a somewhat later as well as longer peak MWP warming than in the present paper. The level of warmth during the peak of the MWP in the second half of the 10th century, equalling or slightly exceeding the mid-20th century warming, is in agreement with the results from other more recent large-scale multi-proxy temperature reconstructions by Moberg et al. (2005), Mann et al. (2008, 2009), Ljungqvist (2010), and Ljungqvist et al. (2012). |
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