Is the PDO elephant knocking at the door again ?

NASA has just drawn our attention to their interesting map of the PDO (Pacific Decadal Oscillation) anomaly for April 14–21. As NASA says, “…while the La Niña was weakening, the Pacific Decadal Oscillation—a larger-scale, slower-cycling ocean pattern—had shifted to its cool phase.”
Annual PDO

This issue is important to the “greenhouse” debate and arguments over the causes of “global warming” because the ~1976 PDO shift to more positive anomalies can be seen clearly as a warming jump in many long term temperature data. A warming jump that looks unlikely to be caused by small steady increases in the trace gas, atmospheric carbon dioxide.

Much is written on the PDO and just 2 other pages include “The Pacific Decadal Oscillation (PDO)” with a long term graphic of monthly anomalies and, “A Pacific interdecadal climate oscillation with impacts on salmon production”

3 comments to Is the PDO elephant knocking at the door again ?

  • Bob Tisdale

    Warwick: There’s also the shift in the AMO in the mid-seventies to add to the natural causes of warming over the past 30 years. The solar cycle (SC20) preceding the mid 70s was also low in amplitude. The AGW crowd timed their blitz well, but it sounds as though time is working against them now.

    If you haven’t run across the following yet, please take a look. Any thoughts on why global temperature anomaly correlates with a cumulative NINO3.4 curve would be appreciated.


  • WSH

    The PDO in April 08 has dropped further to -1.52. I have also scanned an interesting 1992 short paper in Science Vol 255, 20 Mar 1992, by Richard Kerr, “Unmasking a Shifty Climate System”, which describes the multiple effects of the PDO, some years before the PDO was actually named.
    Kerr 1992 page 2
    Kerr 1992 page 3

  • Peterb

    Thanks Warwick,
    It is possible that the PDO was responsible but around 1975 was also the time of reduction in the number of sites used by GISS and CRU for computer model’s calculation global average temperatures. If PDO was a cause should not the temperatures have gone down by the same amount as the sudden jump?
    Kerr’s paper makes reference to Trenberth who is caught up in the Climategate emails and files showing data manipulation. I think Trenberth’s Global Energy Budget (Kehl&Trenberth 1997 and Trenberth et al 2009) is very biased towards AGW. In the latter, Trenberth has references to the infamous Jones and Hansen. I think the radiation balance by A Maurellis (Physics World May 2003 makes much more sense.
    Using an equation (from Prof Hotel at MIT) to determine overall absorptivity of CO2 in the atmosphere involving partial pressures, temperatures, beam length and the wavelength absorptivity spectrum I calculate that CO2 makes a negligible contribution to incoming or outgoing radiation fluxes.