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The new climate hockeystick

  1. Sep 7, 2008 #1
    The new hockeystick is http://www.pnas.org/content/early/2008/09/02/0805721105.full.pdf

    the abstract:

    They use two methods of reconstruction:

    About those methods they observe:

    So looking at this reconstruction we see the EIV showing a distinct medieval warm period and what also bugs a bit is the addition of the instrumental records, showing a increase of about 1.3 degrees over the last century. It should be noted that the normal temperature increase for the last century used to be about 0.6 degrees per century (for instance http://www.geog.ox.ac.uk/~mnew/teaching/Online_Articles/folland_et_al_temp_uncertainties_GRL_2001.PDF [Broken]).

    What also seems to be strange is the increasing deviation between those temperature records and the reconstruction, staying clearly behind in the last part of the graph.

    Now see what happens if we remove those recorded temperatures.

    See that the temperature range of the reconstructions are indeed close to 0.6 degrees in the last century. So it would be interesting to see where that 1.3 range comes from. Note also that the reconstructions without those instrumental records would not support the claim:

    Last edited by a moderator: May 3, 2017
  2. jcsd
  3. Sep 7, 2008 #2


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    I wonder how the present would be interpreted from historical data, (if records were lost),
    Would we be able to say: A 160sq mile section of the Wilkins ice sheet broke away, or if volcanoes on the sea floor near Fiji (Dugong and Lobster), were active, it seems we know more about the surface of Mars than we do about Earths seafloor.
    I think there are to many butterflies to ever sort out an accurate reason for historical climate.
    Last edited: Sep 7, 2008
  4. Sep 8, 2008 #3


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    I thought one of the more highly criticized points in the original hockey stick was the cut and paste job w/ proxy methods and modern instrument data. Yet it is still in there and as Andre shows it is still misleading to co-join the two. Is there at least some new proposed rational for trying this again, or is the methodology somehow different and I've missed it?
  5. Sep 9, 2008 #4
    It is not only there, it has doubled in size.

    Here some ideas about the last centuries warming:

    See how the inflation starts:



    http://ambio.allenpress.com/perlserv/?request=get-abstract&doi=10.1639%2F0044-7447(2001)030%5B0072%3ACCWATL%5D2.0.CO%3B2&ct=1 [Broken]

    But still not 1.3 degrees.
    Last edited by a moderator: May 3, 2017
  6. Sep 9, 2008 #5


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    Kudos for Andre! Keep up the good work ! :approve:
  7. Sep 10, 2008 #6
    Thanks Vanesch

    Wondering how such a 100% deviation slipped through peer review, when it catches the eye of those who are not qualified to judge immediately. Makes one wonder what else may have slipped through.

    Perhaps it has to do with standards?

    http://muller.lbl.gov/TRessays/23-Medievalglobalwarming.html [Broken]

    Last edited by a moderator: May 3, 2017
  8. Sep 11, 2008 #7
    Andre has initiated a very important discussion with his citation of a PNAS report by a group of meteorologist-environmentalists. The earlier hockey stick data was strongly influenced by urban values while the new treatment uses other sources in its analysis. It also recognizes the regional nature of the problem and introduces this concept in its approach, an important improvement. But any inclusion of urban data must be challenged. Cities have become the major users of human-produced energy as well as growing concentrations of heat-generating human beings. Their size is incredibly larger than in any past age. As shown in the appendix of Michael Crichton’s 2004 book, State of Fear, cities of growing size characteristically show rising temperatures. Direct and indirect temperature readings must systematically exclude urban sources to be considered reliable. Failure to exclude their data will characteristically lead to a hockey-stick result. I have elsewhere cited the rapidly rising energy production catalogued by EIA-DOE https://www.physicsforums.com/showthread.php?t=247597 This is expended heavily in cities and has contributed as much as 20% to the temperature rise seen since 1978.
  9. Sep 14, 2008 #8

    Not really, the previous hockey stick from the third IPCC assessment report was a game of principle components, strongly enlarging the effect of a http://www.eman-rese.ca/eman/reports/publications/Forest/images/page16.gif [Broken] which showed abnormal growth likely related to the damage. The debunking was endorsed by the http://www.climateaudit.org/pdf/others/07142006_Wegman_Report.pdf [Broken] which seems to have vanished mysteriously from the governmental pages.

    Anyway, Mann et al 2008 implicitely accept that there were some issues using tree rings:

    What this seem to mean is that the interpretation of records as indirect indicators for climate records suffers from the affirming the consequent fallacy (A then B, B hence A), which seems to be worst with tree rings. As a token thereof, Turbo can tell about how the bad cool and wet summer produced an extreme load of peaches, breaking the branches. Growth of trees is primarily a function of moisture and only secondary temperature.

    It's this logical fallacy that ultimately determines climate policies.

    Hint use the search feature of PF with key word "wegman".
    Last edited by a moderator: May 3, 2017
  10. Sep 19, 2008 #9
    Andre added a new dimension to the hockey-stick problem for me by calling attention to the Wegman report, specifically critical of this group and its data handling practices. I had been focused on the CRU East Anglia and HAD Hadley data used in the report to show the hockey-stick effect in figure 3. I was previously familiar with the use of tree ring data in support of the Maunder minimum sunspot near absence model. http://en.wikipedia.org/wiki/Maunder_minimum http://www.stsci.edu/stsci/meetings/lisa3/beckmanj.html (note the astrophysical extension of magnetic behavior and “global warming” comments)
    Here the main distinction is the support by rising 14C levels to the tree ring narrowing. http://books.google.com/books?id=mK...&hl=en&sa=X&oi=book_result&resnum=9&ct=result
    The 14C rise has never entered the more commonly discussed Little Ice Age model and has, of course, been falling since the last atmospheric atomic tests. 14C production-dilution fluctuation complicates its use in the past event time dating process.

    Wegman asserts the use of a very small number of bristlecone pines from a small area as the data source of a prior report. My knowledge of bristlecone pine growth habits and habitat terrain indicates they are a poor choice for thermal surrogates. I am unable to assign species, sites and numbers to this report at this time (see their figure 1) but will look further and add commentary if I am successful. If you can help me, please do.

    In the meantime, if I am correct about the East Anglia and Hadley data. I hope that you will join me in pointing out the prejudice toward hockey-stick patterns that their inclusion generates. Another kind of Mann et al. artifact seems to be the main point of the red noise studies cited in the Wegman report.
    Last edited by a moderator: Apr 23, 2017
  11. Feb 11, 2009 #10
    RE: the Wegmon report, when all was said and done the effect was a mere ~0.05C in the final reconstruction and did not alter the overall conclusions.
    If you have a problem with the data here is contact information.
    http://www.cru.uea.ac.uk/cru/data/temperature/nhshgl.gif [Broken]

    Their reconstruction is consistent with the CRU data used. And it is very similar what we see in http://en.wikipedia.org/wiki/File:Hockey_stick_chart_ipcc_large.jpg" [Broken]
    Last edited by a moderator: May 4, 2017
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